JP2014023018A - Base station, terminal, communication system, communication method and integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a base station to efficiently notify a terminal of control information in a radio communication system in which the base station and the terminal communicate with each other.SOLUTION: A base station comprises a second control channel generating unit for generating a second control channel different from a first control channel. The second control channel uses one or more E-CCEs associated with a prescribed E-REG. The E-REG is associated with a prescribed resource element in each of a first resource block and a second resource block. The resource element associated with the E-REG in an OFDM symbol cyclically shifts to the frequency direction with the use of a prescribed shift number as the OFDM progresses to the time direction in a prescribed number of the resource blocks in the frequency direction.

Description

  The present invention relates to a base station, a terminal, a communication system, a communication method, and an integrated circuit.

  3GPP (Third Generation Partnership Project) WCDMA (Wideband Code Division Multiple Access), LTE (Long Term Evolution), LTE-A (LTE-Advanced) and IEEE (The Institute of Electrical and Electronics engineers) Wireless LAN, WiMAX (Worldwide) In a wireless communication system such as Interoperability for Microwave Access, there are a plurality of base stations (cells, transmitting stations, transmitting apparatuses, eNodeBs) and terminals (mobile terminals, receiving stations, mobile stations, receiving apparatuses, UEs (User Equipment)). The transmission / reception antennas are respectively provided, and by using MIMO (Multi Input Multi Output) technology, data signals are spatially multiplexed to realize high-speed data communication.

  In such a wireless communication system, when a base station transmits downlink data (a transport block for a downlink shared channel (DL-SCH)) to a terminal, between the base station and the terminal. 1 multiplexes and transmits a demodulation reference signal (also referred to as DMRS; also referred to as Demodulation Reference Signals), which is a known signal. Here, the demodulation reference signal is also referred to as a user equipment specific reference signal (UE-specific RS, terminal-specific (specific) RS). Hereinafter, the demodulation reference signal is also simply referred to as a reference signal.

  For example, the reference signal is multiplexed with downlink data before the precoding process is applied. Therefore, the terminal can measure the equalization channel including the applied precoding process and transmission path state by using the reference signal. That is, the terminal can demodulate the downlink data without being notified of the precoding process applied by the base station.

  Here, the downlink data is mapped to a physical downlink shared channel (PDSCH; Physical Downlink Shared Channel). That is, the reference signal is used for demodulation of PDSCH. Further, for example, the reference signal is transmitted only in a resource block (also referred to as a physical resource block or a resource) to which the corresponding PDSCH is mapped.

  Here, a wireless communication system using a heterogeneous network deployment (HetNet; Heterogeneous Network deployment) such as a macro base station with a wide coverage and an RRH (Remote Radio Head) with a narrower coverage than the macro base station is being studied. . FIG. 18 is a schematic diagram of a wireless communication system using a heterogeneous network arrangement. As illustrated in FIG. 18, for example, the heterogeneous network includes macro base stations 1801, RRH 1802, and RRH 1803.

  In FIG. 18, the macro base station 1801 constructs a coverage 1805, and the RRH 1802 and RRH 1803 construct a coverage 1806 and a coverage 1807, respectively. Further, the macro base station 1801 is connected to the RRH 1802 via the line 1808 and is connected to the RRH 1803 via the line 1809. Thereby, the macro base station 1801 can transmit and receive data signals and control signals (control information) to and from the RRH 1802 and the RRH 1803. Here, for example, a wired line such as an optical fiber or a wireless line using a relay technique is used for the line 1808 and the line 1809. At this time, a part or all of the macro base stations 1801, RRH 1802, and RRH 1803 use the same resource, so that the overall frequency use efficiency (transmission capacity) in the area of the coverage 1805 can be improved.

  In addition, when the terminal 1804 is located in the coverage 1806, the terminal 1804 can perform single cell communication with the RRH 1802. Further, when the terminal 1804 is located near the edge (cell edge) of the coverage 1806, a countermeasure against interference of the same channel from the macro base station 1801 is required. Here, as multi-cell communication (cooperative communication) between the macro base station 1801 and the RRH 1802, a method of reducing or suppressing interference with the terminal 1804 in the cell edge region by performing inter-base station cooperative communication between adjacent base stations. Is being considered. For example, as a method for reducing or suppressing interference by inter-base station cooperative communication, a CoMP (Cooperative Multipoint) transmission method or the like has been studied (Non-patent Document 1).

3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Coordinated multi-point operation for LTE physical layer aspects (Release 11), September 2011, 3GPP TR 36.819 V11.0.0 (2011-09).

  However, when a conventional method is used as a control information notification method from a base station to a terminal in a heterogeneous network arrangement and / or a CoMP transmission method, there is a problem of capacity in a control information notification area. As a result, control information for the terminal cannot be efficiently notified from the base station, which hinders improvement in transmission efficiency in communication between the base station and the terminal.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a base station and a terminal capable of efficiently reporting control information for the terminal in the communication system in which the base station and the terminal communicate. A communication system, a communication method, and an integrated circuit are provided.

  (1) The present invention has been made to solve the above-described problem, and a base station according to an aspect of the present invention includes a resource element including an OFDM symbol and a subcarrier, and a predetermined number of the resource elements. A base station that communicates with a terminal using a resource block that is configured and a resource block pair that is composed of a first resource block and a second resource block that are two resource blocks that are continuous in the time direction. A second control channel generating unit configured to generate a second control channel to be transmitted using a reference signal of an antenna port different from the first control channel, wherein the second control channel is a predetermined signal Transmitted to the terminal using one or more E-CCEs associated with the E-REG, wherein the E-REG is the first resource; In each of the lock and the second resource block, the resource element associated with the predetermined resource element and associated with the E-REG in the OFDM symbol is the OFDM symbol in the predetermined number of resource blocks in the frequency direction. As the signal advances in the time direction, it shifts cyclically in the frequency direction using a predetermined number of shifts.

  (2) In addition, a base station according to an aspect of the present invention is the base station described above, and is used for transmission of the second control channel when the second control channel is transmitted using local mapping. When the E-CCE is associated with a plurality of the E-REGs in one resource block pair and the second control channel is transmitted using distributed mapping, the E-CCE is used for transmission of the second control channel. The E-CCE to be associated is associated with the plurality of E-REGs in the plurality of resource block pairs.

  (3) A base station according to an aspect of the present invention is the base station described above, wherein the predetermined number of E-REGs associated with the first resource block and the second resource block are associated with the second resource block. It is equal to the predetermined number of E-REGs.

  (4) In addition, a terminal according to an aspect of the present invention includes a resource element configured with an OFDM symbol and a subcarrier, a resource block configured with a predetermined number of the resource elements, and the two continuous in the time direction. A terminal that communicates with a base station using a resource block pair composed of a first resource block and a second resource block, which are resource blocks, and refers to an antenna port different from the first control channel A control channel processing unit for detecting a second control channel using a signal, wherein the second control channel uses one or more E-CCEs associated with a predetermined E-REG, and The E-REG is transmitted from the station, and the E-REG is predetermined in each of the first resource block and the second resource block. The resource element associated with the resource element and associated with the E-REG in the OFDM symbol uses a predetermined number of shifts as the OFDM symbol progresses in the time direction in the predetermined number of resource blocks in the frequency direction. Shifts cyclically in the frequency direction.

  (5) A terminal according to an aspect of the present invention is the terminal described above, and when the second control channel is transmitted using local mapping, the E used for transmission of the second control channel. -CCE is associated with a plurality of the E-REGs in one resource block pair, and when the second control channel is transmitted using distributed mapping, the CCE is used for transmission of the second control channel The E-CCE is associated with the plurality of E-REGs in the plurality of resource block pairs.

  (6) A terminal according to an aspect of the present invention is the terminal described above, wherein the predetermined number of E-REGs associated with the first resource block and the E- associated with the second resource block. It is equal to the predetermined number of REGs.

  (7) Further, a communication system according to an aspect of the present invention includes a resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, A communication system in which a terminal and a base station communicate with each other using a resource block pair composed of a first resource block and a second resource block that are the resource blocks, wherein the base station A second control channel generation unit that generates a second control channel to be transmitted using a reference signal of an antenna port different from the control channel of the control channel, wherein the terminal detects the second control channel And a second control channel using one or more E-CCEs associated with a predetermined E-REG. The E-REG is transmitted from the base station to the terminal, and the E-REG is associated with the predetermined resource element in each of the first resource block and the second resource block, and is transmitted to the E-REG in the OFDM symbol. The resource elements to be associated cyclically shift in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction.

  (8) A communication system according to an aspect of the present invention is the communication system described above, and is used for transmission of the second control channel when the second control channel is transmitted using local mapping. When the E-CCE is associated with a plurality of the E-REGs in one resource block pair and the second control channel is transmitted using distributed mapping, the E-CCE is used for transmission of the second control channel. The E-CCE to be associated is associated with a plurality of the E-REGs in the plurality of resource block pairs.

  (9) A communication system according to an aspect of the present invention is the communication system described above, wherein the predetermined number of the E-REGs associated with the first resource block and the second resource block are associated with the second resource block. It is equal to the predetermined number of E-REGs.

  (10) In addition, a communication method according to an aspect of the present invention includes a resource element configured with an OFDM symbol and a subcarrier, a resource block configured with a predetermined number of the resource elements, and two continuous in the time direction. A communication method of a base station that communicates with a terminal using a resource block pair composed of a first resource block and a second resource block that are the resource blocks, and is different from the first control channel Generating a second control channel to be transmitted using an antenna port reference signal, wherein the second control channel uses one or more E-CCEs associated with a predetermined E-REG. And the E-REG is transmitted to each of the first resource block and the second resource block. The resource element associated with the predetermined resource element and associated with the E-REG in the OFDM symbol has a predetermined number as the OFDM symbol advances in the time direction in a predetermined number of resource blocks in the frequency direction. It shifts cyclically in the frequency direction using the number of shifts.

  (11) In addition, a communication method according to an aspect of the present invention includes a resource element including an OFDM symbol and a subcarrier, a resource block including a predetermined number of the resource elements, A communication method for a terminal that communicates with a base station using a resource block pair composed of a first resource block and a second resource block, which are the resource blocks, and is different from the first control channel Using a reference signal of the antenna port to detect a second control channel, the second control channel using one or more E-CCEs associated with a predetermined E-REG; Transmitted from the base station, and the E-REG is transmitted in each of the first resource block and the second resource block. The resource element associated with the predetermined resource element and associated with the E-REG in the OFDM symbol has a predetermined number of shifts as the OFDM symbol advances in the time direction in the predetermined number of resource blocks in the frequency direction. To cyclically shift in the frequency direction.

  (12) An integrated circuit according to an aspect of the present invention includes a resource element including an OFDM symbol and a subcarrier, a resource block including a predetermined number of the resource elements, and two continuous time elements An integrated circuit of a base station that communicates with a terminal using a resource block pair constituted by a first resource block and a second resource block, which are the resource blocks, and is different from the first control channel A function for generating a second control channel to be transmitted using a reference signal of an antenna port is realized, and the second control channel uses one or more E-CCEs associated with a predetermined E-REG. And the E-REG is transmitted in each of the first resource block and the second resource block. The resource element associated with the predetermined resource element and associated with the E-REG in the OFDM symbol has a predetermined shift as the OFDM symbol proceeds in the time direction in a predetermined number of the resource blocks in the frequency direction. The number is used to cyclically shift in the frequency direction.

  (13) In addition, an integrated circuit according to an aspect of the present invention includes a resource element including an OFDM symbol and a subcarrier, a resource block including a predetermined number of the resource elements, and two continuous resources in the time direction. An integrated circuit of a terminal that communicates with a base station using a resource block pair composed of a first resource block and a second resource block, which are the resource blocks, and is different from the first control channel A function of detecting a second control channel using a reference signal of an antenna port is realized, and the second control channel uses one or more E-CCEs associated with a predetermined E-REG, The E-REG is transmitted from the base station, and the E-REG is in each of the first resource block and the second resource block. The resource element associated with the fixed resource element and associated with the E-REG in the OFDM symbol has a predetermined number of shifts as the OFDM symbol advances in the time direction in the predetermined number of resource blocks in the frequency direction. To cyclically shift in the frequency direction.

  According to the present invention, in a wireless communication system in which a base station and a terminal communicate, the base station can efficiently notify control information for the terminal.

It is a schematic block diagram which shows the structure of the base station 100 which concerns on the 1st Embodiment of this invention. It is a schematic block diagram which shows the structure of the terminal 200 which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the sub-frame which the base station 100 transmits. It is a figure which shows an example of one resource block pair which the base station 100 maps. It is a figure which shows an example in case the number of E-REG comprised by one RB is 16, and E-PDCCH is distributed-mapped. It is a figure which shows an example in case the number of E-REG comprised by one RB is 16, and E-PDCCH is mapped locally. It is a figure which shows an example in case the number of E-REG comprised by one RB is 8, and E-PDCCH is distributed-mapped. It is a figure which shows an example in case the number of E-REG comprised by one RB is 8, and E-PDCCH is locally mapped. It is a figure which shows an example of a structure of E-REG. It is a figure which shows an example of a structure of E-REG. It is an example of the numerical formula from which the E-REG number and E-CCE number in the RB pair used as the second control channel region are obtained. It is an example of the numerical formula from which the E-REG number and E-CCE number in the RB pair used as the second control channel region are obtained. It is a figure which shows an example of a structure of E-REG. It is a figure which shows an example of a structure of E-REG. It is an example of the numerical formula from which the E-REG number in the RB pair used as the second control channel region is obtained. It is an example of the E-CCE structure in local mapping. It is a figure which shows an example of the numerical formula for associating the resource element and E-CCE in local mapping. 1 is a schematic diagram of a wireless communication system using a heterogeneous network arrangement.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described. The communication system according to the first embodiment includes a base station (transmitting device, cell, transmission point, transmitting antenna group, transmitting antenna port group, component carrier, eNodeB) and terminal (terminal device, mobile terminal, receiving point, receiving terminal). , Receiving device, receiving antenna group, receiving antenna port group, UE).

  In the communication system of the present invention, the base station 100 transmits control information and information data through the downlink in order to perform data communication with the terminal 200.

  Here, the control information is subjected to error detection coding processing and the like, and is mapped to the control channel. The control channel (PDCCH; Physical Downlink Control Channel) is subjected to error correction coding processing and modulation processing, and is different from the first control channel (first physical control channel) region or the first control channel region. Transmission / reception is performed via two control channel (second physical control channel) regions. However, the physical control channel referred to here is a kind of physical channel and is a control channel defined on a physical frame. Hereinafter, a control channel mapped to the first control channel region is also referred to as a first control channel, and a control channel mapped to the second control channel region is also referred to as a second control channel. The first control channel is also referred to as PDCCH, and the second control channel is also referred to as E-PDCCH (Enhanced PDCCH).

  From one viewpoint, the first control channel is a physical control channel that uses the same transmission port (antenna port) as the cell-specific reference signal. The second control channel is a physical control channel that uses the same transmission port as the terminal-specific reference signal. The terminal 200 demodulates the first control channel using the cell-specific reference signal, and demodulates the second control channel using the terminal-specific reference signal. The cell-specific reference signal is a reference signal common to all terminals in the cell, and is a reference signal that can be used by any terminal because it is inserted into almost all resources. Therefore, any terminal can demodulate the first control channel. On the other hand, the terminal-specific reference signal is a reference signal inserted only in the allocated resource, and can perform adaptively a precoding process and a beamforming process like data. In this case, the control channel arranged in the second control channel region can obtain adaptive precoding, beamforming gain, and frequency scheduling gain. In addition, the terminal-specific reference signal can be shared by a plurality of terminals. For example, when the control channel arranged in the second control channel region is notified by being distributed to a plurality of resources (for example, resource blocks), the terminal-specific reference signal in the second control channel region is a plurality of Can be served by the terminal. In this case, the control channel arranged in the second control channel region can obtain frequency diversity gain.

  From a different point of view, the control channel (first control channel) mapped to the first control channel region is a physical control channel on the OFDM symbol (symbol) located in the front part of the physical subframe. , Can be arranged over the entire system bandwidth (component carrier (CC)) on these OFDM symbols. In addition, the control channel (second control channel) mapped to the second control channel region is a physical control channel on the OFDM symbol located behind the first control channel of the physical subframe, and these It may be arranged in a part of the system bandwidth on the OFDM symbol. Since the first control channel is arranged on the OFDM symbol dedicated to the control channel located in the front of the physical subframe, it can be received and demodulated before the rear OFDM symbol for the physical data channel. A terminal that monitors only the OFDM symbol dedicated to the control channel can also be received. Moreover, since it can be spread and arranged throughout the CC, inter-cell interference can be randomized. In addition, the first control channel region is a region that is set unique to the base station 100 and is a region that is common to all terminals connected to the base station 100. On the other hand, the second control channel is arranged on the rear OFDM symbol for the shared channel (physical data channel) normally received by the communicating terminal. Further, by performing frequency division multiplexing, the second control channels or the second control channel and the physical data channel can be orthogonally multiplexed (multiplexing without interference). In addition, the second control channel region is a region set for each terminal 200 and is set for each terminal connected to the base station 100. Note that the base station 100 can set the second control channel region to be shared by a plurality of terminals. Further, the first control channel region and the second control channel region are arranged in the same physical subframe. Here, the OFDM symbol is a unit in the time direction for mapping bits of each channel.

  From a different point of view, the first control channel is a cell-specific physical control channel, and is a physical channel that can be acquired (detected) by both the idle terminal and the connected terminal. The second control channel is a terminal-specific physical control channel, and is a physical channel that can be acquired only by a connected terminal. Here, the idle state refers to a state in which the base station does not accumulate RRC (Radio Resource Control) information (RRC_IDLE state), a state in which the mobile station is performing intermittent reception (DRX), etc. This is a state where no operation is performed. On the other hand, the connected state is a state in which data can be immediately transmitted / received, such as a state in which the terminal holds network information (RRC_CONNECTED state) or a state in which the mobile station is not performing intermittent reception (DRX). is there. The first control channel is a channel that can be received by the terminal without depending on terminal-specific RRC signaling. The second control channel is a channel set by terminal-specific RRC signaling, and is a channel that can be received by the terminal by terminal-specific RRC signaling. That is, the first control channel is a channel that can be received by any terminal with a setting limited in advance, and the second control channel is a channel that is easy to change the setting unique to the terminal.

  FIG. 1 is a schematic block diagram showing the configuration of the base station 100 according to the first embodiment of the present invention. In FIG. 1, the base station 100 includes an upper layer 101, a data channel generation unit 102, a second control channel generation unit 103, a terminal-specific reference signal multiplexing unit 104, a precoding unit 105, a first control channel generation unit 106, A cell-specific reference signal multiplexing unit 107, a transmission signal generation unit 108, and a transmission unit 109 are provided.

  Upper layer 101 generates information data (transport block, codeword) for terminal 200 and outputs the information data to data channel region allocation section 102. Here, the information data can be a unit for performing error correction coding processing. The information data can be a unit for performing retransmission control such as HARQ (Hybrid Automatic Repeat reQuest). In addition, the base station 100 can transmit a plurality of information data to the terminal 200.

  A data channel generation unit (data channel region allocation unit, data channel mapping unit, shared channel generation unit) 102 performs adaptive control on the information data output by the upper layer 101 and performs data channel (shared channel, A shared channel, PDSCH (Physical Downlink Shared Channel) is generated. Specifically, the adaptive control in the data channel generation unit 102 uses an encoding process for performing error correction encoding, a scramble process for applying a scramble code unique to the terminal 200, a multi-level modulation method, and the like. A layer mapping process for performing spatial multiplexing such as modulation processing and MIMO is performed. Here, the layer mapping process in the data channel generation unit 102 maps to one or more layers (streams) based on the number of ranks set for the terminal 200.

  The second control channel generation unit (second control channel region allocation unit, second control channel mapping unit, terminal-specific control channel generation unit) 103 is configured so that the base station 100 uses the second control channel region (terminal-specific control channel). When the control information for the terminal 200 is transmitted via the region), a control channel to be transmitted via the second control channel region is generated. Here, when the second control channel region is set to the shared channel region, the data channel generation unit 102 and the second control channel generation unit 103 are also referred to as a shared channel region allocation unit. The data channel and / or the second control channel is also referred to as a shared channel. The second control channel is also referred to as E-PDCCH (Enhanced PDCCH) or terminal-specific control channel.

  Terminal-specific reference signal multiplexing section (terminal-specific reference signal generation section, terminal-specific control channel demodulation reference signal multiplexing section, terminal-specific control channel demodulation reference signal generation section) 104 is a terminal-specific reference signal (data Channel demodulation reference signal, second control channel demodulation reference signal, shared channel demodulation reference signal, terminal-specific control channel demodulation reference signal, DM-RS (Demodulation Reference Signal), DRS (Dedicated Reference Signal), Precoded RS UE-specific RS) and multiplex the terminal-specific reference signal in the shared channel region. Terminal specific reference signal multiplexing section 104 receives an initial value for generating a scramble code constituting the terminal specific reference signal. The terminal-specific reference signal multiplexing unit 104 generates a terminal-specific reference signal based on the input initial value of the scramble code. Here, the terminal-specific reference signal is set based on the data channel or the second control channel to be multiplexed, and multiplexed on each layer (antenna port) of the data channel or the second control channel. Note that the terminal-specific reference signal is preferably orthogonal and / or quasi-orthogonal between layers. Note that the terminal-specific reference signal multiplexing unit 104 may generate a terminal-specific reference signal and multiplex it in the transmission signal generation unit 108 described later.

  Precoding section 105 performs precoding processing on the data channel, second control channel and / or terminal specific reference signal output from terminal specific reference signal multiplexing section 104. Here, the precoding process may be different depending on whether the terminal-specific reference signal is used by a plurality of terminals or the terminal-specific reference signal is used by one terminal. When the precoding process is used by the terminal 200, it is preferable to perform phase rotation and / or amplitude control on the input signal so that the terminal 200 can efficiently receive the precoding process. For example, the precoding process is preferably performed so that the reception power of terminal 200 is maximized, interference from the adjacent cell is reduced, or interference to the adjacent cell is reduced. Also, processing by a predetermined precoding matrix, CDD (Cyclic Delay Diversity), transmission diversity (SFBC (Spatial Frequency Block Code), STBC (Spatial Time Block Code), TSTD (Time Switched Transmission Diversity), FSTD (Frequency Switched) Transmission Diversity) etc. can be used, but is not limited to this. Further, when the terminal-specific reference signal is used by a plurality of terminals, the precoding process preferably uses a process based on a precoding matrix determined in advance, CDD, and transmission diversity. Here, when the base station 100 feeds back a plurality of types of PMI (Precoding Matrix Indicator), which is feedback information related to precoding processing, from the terminal 200, the base station 100 Precoding processing can be performed based on the result of performing arithmetic operations such as multiplication on a plurality of PMIs.

  Here, the terminal-specific reference signal is a signal known to the base station 100 and the terminal 200. Here, when the precoding unit 105 performs precoding processing specific to the terminal 200, when the terminal 200 demodulates the data channel and / or the second control channel, the terminal-specific reference signals are the base station 100 and the terminal 200, respectively. The channel condition in the downlink between and the precoding weight equalization channel by the precoding unit 105 can be estimated. That is, base station 100 does not need to notify terminal 200 of the precoding weight by precoding section 105, and can demodulate the precoded signal.

  The first control channel generation unit (first control channel region allocation unit, first control channel mapping unit, cell specific control channel generation unit) 106 is configured so that the base station 100 can control the first control channel region (cell specific control channel). When transmitting control information for the terminal 200 via a region), a control channel to be transmitted via the first control channel region is generated. Here, the control channel transmitted through the first control channel region is also referred to as a first control channel. The first control channel is also referred to as a cell-specific control channel.

  A cell-specific reference signal multiplexing unit (cell-specific reference signal generation unit) 107 is a cell known by the base station 100 and the terminal 200 in order to measure a downlink transmission path condition between the base station 100 and the terminal 200. A unique reference signal (reference signal for transmission path condition measurement, CRS (Common RS), Cell-specific RS, Non-precoded RS, cell-specific control channel demodulation reference signal, first control channel demodulation reference signal) is generated. . The generated cell-specific reference signal is multiplexed with the signal output by the first control channel generation unit 106. Note that the cell-specific reference signal multiplexing unit 107 may generate a cell-specific reference signal and multiplex it in the transmission signal generation unit 108 described later.

  Here, as the cell-specific reference signal, any signal (sequence) can be used as long as both the base station 100 and the terminal 200 are known signals. For example, a random number or a pseudo noise sequence based on parameters assigned in advance such as a number (cell ID) unique to the base station 100 can be used. In addition, as a method of orthogonalizing between antenna ports, a method in which resource elements for mapping cell-specific reference signals are mutually null (zero) between antenna ports, a method of code division multiplexing using a pseudo-noise sequence, or a combination thereof The method etc. can be used. Note that the cell-specific reference signal may not be multiplexed in all subframes, and may be multiplexed only in some subframes.

  The cell-specific reference signal is a reference signal that is multiplexed after the precoding process by the precoding unit 105. Therefore, terminal 200 can measure a downlink transmission path condition between base station 100 and terminal 200 using a cell-specific reference signal, and a signal that has not been subjected to precoding processing by precoding section 105. Can be demodulated. For example, the first control channel can be demodulated by the cell-specific reference signal. The first control channel can be demodulated by CRS.

  The transmission signal generation unit (channel mapping unit) 108 performs mapping processing on the signal output from the cell-specific reference signal multiplexing unit 107 to the resource element of each antenna port. Specifically, the transmission signal generation unit 108 maps the data channel to the data channel region of the shared channel region, and maps the second control channel to the second control channel region of the shared channel region. Furthermore, the transmission signal generation unit 108 maps the first control channel to a first control channel region different from the second control channel region. Here, the base station 100 can map control channels addressed to a plurality of terminals in the first control channel region and / or the second control channel region. Note that the base station 100 may map the data channel to the second control channel region. For example, when the second control channel is not mapped to the second control channel region set in the terminal 200 by the base station 100, the data channel may be mapped to the second control channel region.

  Here, the first control channel and the second control channel are a control channel to be transmitted through different resources and / or a control channel to be demodulated using different reference signals, and / or the terminal 200, respectively. This is a control channel that can be transmitted according to different RRC states. Each control channel can map control information of any format. A format of control information that can be mapped can be defined for each control channel. For example, the first control channel can map control information of all formats, and the second control channel can map control information of some formats. For example, the first control channel can map control information of all formats, and the second control channel maps control information of a format including data channel allocation information using a terminal-specific reference signal. Can do.

  Here, the PDCCH or ePDCCH is used for notifying (designating) downlink control information (DCI) to the terminal. For example, the downlink control information includes information related to PDSCH resource allocation, information related to MCS (Modulation and Coding scheme), information related to scrambling identity (also referred to as scrambling link identifier), reference signal sequence identity (base sequence identity, Information on the base sequence identifier and the base sequence index).

  A plurality of formats are defined for downlink control information transmitted on PDCCH or ePDCCH. Here, the format of the downlink control information is also referred to as a DCI format. That is, a field for each uplink control information is defined in the DCI format.

  For example, DCI format 1 and DCI format 1A used for scheduling one PDSCH (one PDSCH codeword, one downlink transport block transmission) in one cell are defined as DCI formats for the downlink. The That is, DCI format 1 and DCI format 1A are used for transmission on PDSCH using one transmission antenna port. The DCI format 1 and the DCI format 1A are also used for transmission on the PDSCH by transmission diversity (TxD; Transmission Diversity) using a plurality of transmission antenna ports.

  Further, as DCI formats for downlink, DCI format 2 and DCI format used for scheduling one PDSCH (up to two PDSCH codewords, up to two downlink transport transmissions) in one cell. 2A and DCI format 2B and DCI format 2C are defined. That is, DCI format 2, DCI format 2A, DCI format 2B, and DCI format 2C are used for transmission on a MIMO SDM (Multiple Input Multiple Domain Multiplexing) PDSCH using a plurality of transmission antenna ports.

  Here, the format of the control information is defined in advance. For example, the control information can be defined according to the purpose of the base station 100 notifying the terminal 200. Specifically, the control information includes downlink data channel allocation information for terminal 200, uplink data channel (PUSCH: Physical Uplink Shared Channel) and control channel (PUCCH: Physical Uplink Control Channel) allocation for terminal 200. Information, information for controlling transmission power for the terminal 200, and the like can be defined. Therefore, for example, when the base station 100 transmits downlink information data to the terminal 200, the control channel to which control information including downlink data channel allocation information for the terminal 200 is mapped, and its control A data channel to which information data assigned based on the information is mapped is transmitted. Further, for example, when allocating an uplink data channel to the terminal 200, the base station 100 transmits a control channel to which control information including uplink data channel allocation information for the terminal 200 is mapped. In addition, the base station 100 can transmit a plurality of different control information or the same control information to the same terminal 200 in the same subframe in different formats or the same format. Note that, when the base station 100 transmits downlink information data to the terminal 200, the subframe that transmits the control channel to which control information including the allocation information of the downlink data channel for the terminal 200 is mapped. It is also possible to transmit downlink data channels in different subframes.

  Here, since the first control channel region is a region unique to the base station 100, it is also referred to as a cell-specific control channel region. Further, the second control channel region is a region specific to terminal 200 set from base station 100 through RRC signaling, and is also referred to as a terminal-specific control channel region. The second control channel region is set in units of resource block pairs. Here, the resource block pair is an area in which two resource blocks (RB: Resource Block) configured by a predetermined frequency direction area and a predetermined time direction area are continuously arranged in the time direction. In the resource block pair, the first half resource block in the time direction is also referred to as a first resource block, and the second half resource block in the time direction is also referred to as a second resource block.

  Also, the base station 100 and the terminal 200 transmit and receive signals in an upper layer (Higher layer). For example, the base station and the terminal are also called a radio resource control signal (RRC signaling; Radio Resource Control signal, RRC message; Radio Resource Control message, RRC information; Radio Resource Control information) in the RRC layer (Layer 3). Send and receive. Here, in the RRC layer, a dedicated signal transmitted to a certain terminal by the base station is also referred to as a dedicated signal. That is, the setting (information) notified by the base station using the dedicated signal is a setting specific to a certain terminal.

  Further, the base station and the terminal transmit and receive MAC control elements in a MAC (Media Access Control) layer (layer 2). Here, the RRC signaling and / or MAC control element is also referred to as an upper layer signal (Higher layer signaling).

  The transmission unit 109 performs inverse fast Fourier transform (IFFT), addition of a guard interval, conversion processing to a radio frequency, etc., and then the number of one or more transmission antennas (number of transmission antenna ports). Transmit from the transmitting antenna.

  FIG. 2 is a schematic block diagram showing the configuration of the terminal 200 according to the first embodiment of the present invention. In FIG. 2, terminal 200 includes reception section 201, reception signal processing section 202, propagation path estimation section 203, control channel processing section 204, data channel processing section 205, and higher layer 206.

  The receiving unit 201 receives a signal transmitted from the base station 100 by one or a plurality of receiving antennas (the number of receiving antenna ports), performs a conversion process from a radio frequency to a baseband signal, and an added guard. Time frequency conversion processing such as interval removal and fast Fourier transform (FFT) is performed.

  The received signal processing unit 202 demaps (separates) the signal mapped by the base station 100. Specifically, received signal processing section 202 demaps the first control channel and / or the second control channel and / or data channel, and outputs the result to control channel processing section 204. Also, received signal processing section 202 demaps the multiplexed cell-specific reference signal and / or terminal-specific reference signal and outputs the result to propagation path estimation section 203.

  The propagation path estimation unit 203 performs propagation path estimation for the resources of the first control channel and / or the second control channel and / or the data channel based on the cell-specific reference signal and / or the terminal-specific reference signal. The propagation path estimation unit 203 outputs the estimation result of the propagation path estimation to the control channel processing unit 204 and / or the data channel processing unit 205. Based on the terminal-specific reference signal multiplexed on the data channel and / or the second control channel, the propagation path estimation unit 203 varies the amplitude and phase in each resource element for each reception antenna port of each transmission antenna port. (Frequency response, transfer function) is estimated (propagation channel estimation), and a channel estimation value is obtained. Here, the initial value of the scramble code constituting the terminal-specific reference signal is input to the propagation path estimation unit 203, and the terminal-specific reference signal is determined based on the initial value and the like. Further, the propagation path estimation unit 203 estimates amplitude and phase fluctuations in each resource element for each reception antenna port of each transmission antenna port based on the cell-specific reference signal multiplexed on the first control channel. Then, a propagation path estimation value is obtained.

  The control channel processing unit 204 searches for a control channel addressed to the terminal 200 mapped to the first control channel region and / or the second control channel region. Here, the control channel processing unit 204 sets a first control channel region and / or a second control channel region as a control channel region for searching for a control channel. The setting of the second control channel region is performed through higher layer control information (for example, RRC (Radio Resource Control) signaling) that the base station 100 notifies the terminal 200 of. For example, the setting of the second control channel region is control information for setting the second control channel as the terminal-specific setting information of the second control channel, and is setting information specific to the terminal 100. Details of the setting of the second control channel region will be described later.

  For example, when the terminal-specific setting information of the second control channel is notified by the base station 100 and the second control channel region is set, the control channel processing unit 204 is mapped to the second control channel region A control channel addressed to terminal 200 is searched. In this case, the control channel processing unit 204 may also search for a partial region in the first control channel region. For example, the control channel processing unit 204 may also search for a cell-specific search region in the first control channel region. In addition, when the base station 100 does not notify the terminal-specific setting information of the second control channel and the second control channel region is not set, the control channel processing unit 204 is mapped to the first control channel region. A control channel addressed to terminal 200 is searched.

  Here, when searching for a control channel addressed to the terminal 200 mapped to the second control channel region, the control channel processing unit 204 uses a terminal-specific reference signal to demodulate a possible control channel. In addition, when searching for a control channel addressed to the terminal 200 mapped to the first control channel region, the control channel processing unit 204 uses a cell-specific reference signal to demodulate a possible control channel.

  Specifically, the control channel processing unit 204 demodulates and controls all or part of the control channel candidates obtained based on the type of control information, the location of the mapped resource, the size of the mapped resource, and the like. A decoding process is performed to search sequentially. The control channel processing unit 204 uses an error detection code (for example, CRC (Cyclic Redundancy Check) code) added to the control information as a method for determining whether or not the control information is addressed to the terminal 200. Such a search method is also called blind decoding.

  Further, when the control channel processing unit 204 detects a control channel addressed to the terminal 200, the control channel processing unit 204 identifies control information mapped to the detected control channel, and is shared by the entire terminal 200 (including higher layers), and is downlinked. It is used for various controls in terminal 200 such as data channel reception processing, uplink data channel and control channel transmission processing, and uplink transmission power control.

  When control information including downlink data channel allocation information is mapped to the detected control channel, the control channel processing unit 204 sends the data channel demapped by the received signal processing unit 202 to the data channel processing unit 205. Output.

  The data channel processing unit 205 performs channel compensation processing (filter processing), layer demapping using the channel estimation result input from the channel estimation unit 203 on the data channel input from the control channel processing unit 204. Processing, demodulation processing, descrambling processing, error correction decoding processing, and the like are performed and output to the upper layer 206. Note that a resource element to which no terminal-specific reference signal is mapped performs channel estimation by performing interpolation or averaging in the frequency direction and the time direction based on the resource element to which the terminal-specific reference signal is mapped. In the propagation path compensation processing, propagation path compensation is performed on the input data channel using the estimated propagation path estimation value, and a signal for each layer based on the information data is detected (restored). As the detection method, equalization of ZF (Zero Forcing) norm and MMSE (Minimum Mean Square Error) norm, turbo equalization, interference removal, etc. can be used. In the layer demapping process, the demapping process is performed on the signal for each layer to the respective information data. The subsequent processing is performed for each information data. In the demodulation process, demodulation is performed based on the modulation method used. In the descrambling process, the descrambling process is performed based on the used scramble code. In the decoding process, an error correction decoding process is performed based on the applied encoding method.

  FIG. 3 is a diagram illustrating an example of a subframe transmitted by the base station 100. In this example, one subframe having a system bandwidth composed of 12 physical resource block pairs (PRBs) is shown. In the following description, the resource block pair is also described simply as a resource block, PRB or RB. That is, in the following description, a resource block, PRB or RB includes a resource block pair. In the subframe, the first zero or more OFDM symbols are the first control channel region. The number of OFDM symbols in the first control channel region is notified to the terminal. For example, in the first control channel region, a dedicated notification region can be set for the first OFDM symbol, and notification can be dynamically made for each subframe. In addition, the first control channel region can be notified semi-statically using the control information of the upper layer. An area other than the first control channel area is a shared channel area. The shared channel region includes a data channel region and / or a second control channel region. In the example of FIG. 3, PRB3, PRB4, PRB9, and PRB11 are the second control channel regions.

  Here, the base station 100 notifies (sets) the second control channel region to the terminal 200 through higher layer control information. For example, the control information for setting the second control channel region is control information set for each PRB pair or each group of PRB pairs. In the example of FIG. 3, PRB3, PRB4, PRB9, and PRB11 are set as the second control channel region. Further, the second control channel region is assigned in units of a predetermined number of PRBs. For example, the predetermined number of PRBs can be 4. In that case, the base station 100 sets a multiple of 4 PRBs in the terminal 200 as the second control channel region.

  FIG. 4 is a diagram illustrating an example of one resource block pair mapped by the base station 100. One resource block is composed of a predetermined frequency direction region and a predetermined time direction region. In one resource block pair, two resource blocks are continuously arranged in the time direction. In the resource block pair, the first half resource block in the time direction is also referred to as a first resource block, and the second half resource block in the time direction is also referred to as a second resource block. FIG. 4 shows one resource block pair, and one resource block is composed of 12 subcarriers in the frequency direction and 7 OFDM symbols in the time direction. A resource composed of one OFDM symbol and one subcarrier is called a resource element. Resource block pairs are arranged in the frequency direction, and the number of resource block pairs can be set for each base station. For example, the number of resource block pairs can be set to 6 to 110. The width in the frequency direction at that time is called a system bandwidth. The time direction of the resource block pair is called a subframe. Of each subframe, the seven OFDM symbols before and after in the time direction are also called slots. In the following description, a resource block pair is also simply referred to as a resource block.

  In FIG. 4, among the shaded resource elements, R0 to R3 indicate cell-specific reference signals of antenna ports 0 to 3, respectively. Hereinafter, the cell-specific reference signals of the antenna ports 0 to 3 are also referred to as CRS (Common Reference Signal). Here, although the CRS shown in FIG. 4 is a case of four antenna ports, the number can be changed, for example, CRS of one antenna port or two antenna ports can be mapped.

  In FIG. 4, the cell-specific reference signals of the antenna ports 15 to 22 can be mapped as cell-specific reference signals different from the cell-specific reference signals of the antenna ports 0 to 3. Hereinafter, the cell-specific reference signals of the antenna ports 15 to 22 are also referred to as channel state information reference signals (CSI-RS). In FIG. 4, among the shaded resource elements, C <b> 1 to C <b> 4 indicate transmission path condition measurement reference signals of CDM (Code Division Multiplexing) group 1 to CDM group 4, respectively. The channel state measurement reference signal is first mapped with an orthogonal code using a Walsh code, and then a scramble code using a Gold code is superimposed thereon. Further, the transmission path condition measurement reference signal is code-division multiplexed by orthogonal codes such as Walsh codes in the CDM group. Further, the transmission path condition measurement reference signals are frequency division multiplexed (FDM) between CDM groups. Further, the transmission path condition measurement reference signal of the antenna ports 15 and 16 is mapped to C1, the transmission path condition measurement reference signal of the antenna ports 17 and 18 is mapped to C2, and the transmission path condition measurement of the antenna ports 19 and 20 is performed. The reference signal for mapping is mapped to C3, and the reference signal for transmission path condition measurement of the antenna ports 21 and 22 is mapped to C4. Also, the transmission path condition measurement reference signal can be set as reference signals corresponding to the eight antenna ports of the antenna ports 15 to 22. Also, the transmission path condition measurement reference signals can be set as reference signals corresponding to the four antenna ports of the antenna ports 15 to 18. Also, the transmission path condition measurement reference signal can be set as a reference signal corresponding to the two antenna ports of the antenna ports 15 to 16. Also, the transmission path condition measurement reference signal can be set as a reference signal corresponding to one antenna port of the antenna port 15. Also, the channel state measurement reference signal can be mapped to some subframes, for example, can be mapped for each of a plurality of subframes. Further, the resource element for mapping the transmission path condition measurement reference signal may be different from the resource element shown in FIG. Further, a plurality of patterns may be defined in advance as the mapping pattern for the resource element of the transmission path condition measurement reference signal. Further, the base station 100 can set a plurality of transmission path condition measurement reference signals for the terminal 200. Further, the transmission power of the reference signal for channel condition measurement can be further set, for example, the transmission power can be made zero. Base station 100 sets a reference signal for transmission path status measurement as terminal-specific control information for terminal 200 through RRC signaling. Based on the setting from base station 100, terminal 200 generates feedback information using a CRS and / or a transmission path condition measurement reference signal.

  In FIG. 4, among the shaded resource elements, D1 to D2 indicate terminal-specific reference signals (DM-RSs) of CDM (Code Division Multiplexing) group 1 to CDM group 2, respectively. The terminal-specific reference signal is first mapped with an orthogonal code using a Walsh code, and then a pseudo-random sequence using a Gold code is superimposed as a scrambled sequence. Also, the terminal-specific reference signal is code division multiplexed by orthogonal codes such as Walsh codes in the CDM group. Also, the terminal-specific reference signals are FDM between CDM groups. Here, the terminal-specific reference signal can be mapped to a maximum of 8 ranks using 8 antenna ports (antenna ports 7 to 14) according to the control channel and data channel mapped to the resource block pair. . Further, the terminal-specific reference signal can change the CDM spreading code length and the number of mapped resource elements according to the number of ranks to be mapped.

  For example, the terminal-specific reference signal in the case where the rank number is 1 to 2 is configured with the spreading code length of 2 chips as the antenna ports 7 to 8 and mapped to the CDM group 1. The terminal-specific reference signal in the case where the number of ranks is 3 to 4, in addition to the antenna ports 7 to 8, is configured as the antenna ports 9 to 10 with a spread code length of 2 chips, and is further mapped to the CDM group 2. The terminal-specific reference signals when the rank number is 5 to 8 are configured as antenna ports 7 to 14 with a spreading code length of 4 chips and mapped to CDM group 1 and CDM group 2.

  Here, the terminal-specific reference signals may have different antenna port numbers and configurations depending on the channels (signals) associated therewith. For example, antenna ports 7 to 14 can be used as the antenna port number of the terminal-specific reference signal associated with the shared channel (PDSCH). The antenna ports 107 to 114 can be used as the antenna port number of the terminal-specific reference signal associated with the second control channel (ePDCCH). Note that antenna ports 107 to 110 may be used as the antenna port of the terminal-specific reference signal associated with the second control channel (ePDCCH). Here, the antenna ports 107 to 114 are configured similarly to the antenna ports 7 to 14. Further, the terminal-specific reference signals of antenna ports 107 to 114 may be configured to be partially different from the terminal-specific reference signals of antenna ports 7 to 14. For example, the scramble sequence of terminal-specific reference signals used in antenna ports 107 to 114 may be different from the scramble sequence of terminal-specific reference signals used in antenna ports 7 to 14.

  A resource element filled with white indicates an area (shared channel area) where the shared channel and / or the second control channel is arranged. The shared channel region is mapped to an OFDM symbol that is different from the rear OFDM symbol in the subframe, that is, the OFDM symbol in which the first control channel in the subframe is arranged, and a predetermined number of OFDM symbols are set for each subframe. can do. Note that all or part of the shared channel region can be mapped to a fixed OFDM symbol regardless of the first control channel region in the subframe. In addition, the area where the shared channel is arranged can be set for each resource block pair. Further, the second control channel region may be composed of all OFDM symbols regardless of the number of OFDM symbols in the first control channel region.

  Here, the number of resource blocks can be changed according to the frequency bandwidth (system bandwidth) used by the communication system. For example, 6 to 110 resource blocks can be used, and the unit is also called a component carrier. Further, the base station can set a plurality of component carriers for the terminal by frequency aggregation. For example, the base station configures one component carrier at 20 MHz with respect to the terminal, sets five component carriers continuously and / or discontinuously in the frequency direction, and can be used by the communication system. The bandwidth can be 100 MHz.

  Here, in the radio communication system according to the present embodiment, aggregation of a plurality of serving cells (also simply referred to as cells) is supported in the downlink and uplink (referred to as carrier aggregation). For example, in each serving cell, a transmission bandwidth of up to 110 resource blocks can be used. In carrier aggregation, one serving cell is defined as a primary cell (Pcell). In carrier aggregation, a serving cell other than the primary cell is defined as a secondary cell (Scell; Secondary Cell).

  Furthermore, a carrier corresponding to a serving cell in the downlink is defined as a downlink component carrier (DLCC). Also, a carrier corresponding to a primary cell in the downlink is defined as a downlink primary component carrier (DLPCC; Downlink Primary Component Carrier). A carrier corresponding to a secondary cell in the downlink is defined as a downlink secondary component carrier (DLSCC).

  Furthermore, a carrier corresponding to a serving cell in the uplink is defined as an uplink component carrier (ULCC). Further, a carrier corresponding to a primary cell in the uplink is defined as an uplink primary component carrier (ULPCC; Uplink Primary Component Carrier). Also, a carrier corresponding to a secondary cell in the uplink is defined as an uplink secondary component carrier (ULSCCC).

  That is, in carrier aggregation, a plurality of component carriers are aggregated to support a wide transmission bandwidth. Here, for example, the primary base station can be regarded as a primary cell, and the secondary base station can be regarded as a secondary cell (the base station sets the terminal) (also referred to as HetNet deployment with a carrier aggregation).

  Below, the detail of a structure of PDCCH is demonstrated. The PDCCH is composed of a plurality of control channel elements (CCEs). The number of CCEs used in each downlink component carrier is a downlink cell-specific reference according to the downlink component carrier bandwidth, the number of OFDM symbols constituting the PDCCH, and the number of transmission antennas of the base station 100 used for communication. Depends on the number of signal transmission antenna ports. The CCE is configured by a plurality of downlink resource elements (resources defined by one OFDM symbol and one subcarrier).

  A number for identifying the CCE is assigned to the CCE used between the base station 100 and the terminal 200. The CCE numbering is performed based on a predetermined rule. Here, CCE_t indicates the CCE of CCE number t. The PDCCH is configured by a set (CCE aggregation) including a plurality of CCEs. The number of CCEs constituting this set is referred to as “CCE aggregation level” (CCE aggregation level). The CCE aggregation level constituting the PDCCH is set in the base station according to the coding rate set in the PDCCH and the number of bits of DCI included in the PDCCH. Note that combinations of CCE aggregation levels that may be used for terminals are determined in advance. A set of n CCEs is referred to as “CCE set level n”.

  One resource element group (REG) is composed of four adjacent downlink resource elements in the frequency domain. Furthermore, one CCE is composed of nine different resource element groups distributed in the frequency domain and the time domain. Specifically, for the entire downlink component carrier, all numbered resource element groups are interleaved in resource element group units using a block interleaver, and nine consecutive numbers after interleaving are performed. One CCE is configured by the resource element group.

  In each terminal, an area SS (Search Space) for searching for PDCCH is set. The SS is composed of a plurality of CCEs. The SS is composed of a plurality of CCEs having consecutive numbers starting from the smallest CCE, and the number of CCEs having consecutive numbers is determined in advance. Each CCE aggregation level SS is composed of an aggregation of a plurality of PDCCH candidates. The SS is classified into a CSS (Cell-specific SS) whose number is common in the cell from the smallest CCE and a USS (UE-specific SS) whose number is unique to the terminal from the smallest CCE. CSS is assigned PDCCH to which control information read by a plurality of terminals such as system information or information related to paging is assigned, or a downlink / uplink grant indicating a fallback to a lower transmission scheme or a random access instruction. PDCCH can be arranged.

  The base station transmits the PDCCH using one or more CCEs in the SS set in the terminal 200. Terminal 200 decodes the received signal using one or more CCEs in the SS, and performs processing for detecting the PDCCH addressed to itself (referred to as blind decoding). The terminal 200 sets a different SS for each CCE aggregation level. Thereafter, terminal 200 performs blind decoding using a predetermined combination of CCEs in different SSs for each CCE aggregation level. In other words, terminal 200 performs blind decoding on each PDCCH candidate in a different SS for each CCE aggregation level. This series of processing in terminal 200 is called PDCCH monitoring.

  The second control channel (E-PDCCH, PDCCH on PDSCH, Enhanced PDCCH) is mapped to the second control channel region. When the base station 100 notifies the terminal 200 of the control channel through the second control channel region, the base station 100 sets monitoring of the second control channel for the terminal 200, and sets the second control channel region in the second control channel region. The control channel for terminal 200 is mapped. Further, when the base station 100 notifies the terminal 200 of the control channel through the first control channel region, the base station 100 notifies the terminal 200 of the first control channel regardless of the second control channel monitoring setting. A control channel for terminal 200 may be mapped to the control channel region. Further, when the base station 100 notifies the terminal 200 of the control channel through the first control channel region, the first control is performed when the base station 100 does not set the monitoring of the second control channel for the terminal 200. The control channel for terminal 200 may be mapped to the channel region.

  On the other hand, when the monitoring of the second control channel is set by the base station 100, the terminal 200 is addressed to the control channel addressed to the terminal 200 in the first control channel region and / or addressed to the terminal 200 in the second control channel region. Blind decoding the control channel. In addition, when the monitoring of the second control channel is not set by the base station 100, the terminal 200 does not blind-decode the control channel addressed to the terminal 200 in the first control channel.

  Hereinafter, details of the control channel (E-PDCCH) mapped to the second control channel region will be described.

  The base station 100 sets a second control channel region (potential E-PDCCH) in the terminal 200. The second control channel region is configured by one or more RB pairs. That is, the second control channel region can be set in units of RB pairs. Here, the number of RB pairs constituting the second control channel region can be a multiple of a predetermined value. For example, the number of RB pairs constituting the second control channel region can be a multiple of four. That is, the second control channel region is set in units of RB pairs in which the number of RB pairs is a multiple of four. In addition, for example, the number of RB pairs constituting the second control channel region can be a multiple of two. That is, the second control channel region is set in units of RB pairs in which the number of RB pairs is a multiple of two. Further, the base station 100 can set a search area (search space) in the second control channel area set in the terminal 200. Here, the search area of the second control channel area can be set in units of RB pairs that are multiples of a predetermined value. For example, the unit of the RB pair that sets the search area of the second control channel area can be a multiple of 4. That is, the search area of the second control channel area is set in units of RB pairs in which the number of RB pairs is a multiple of four. Further, for example, the unit of the RB pair that sets the search area of the second control channel area can be a multiple of 2. That is, the search area of the second control channel area is set in units of RB pairs in which the number of RB pairs is a multiple of two.

  Base station 100 maps E-PDCCH for terminal 200 to the set search area of the second control channel area. Moreover, the base station 100 can share all or part of the second control channel region and / or the search region for a plurality of terminals. That is, a plurality of E-PDCCHs for a plurality of terminals can be multiplexed within the second control channel region. Here, the E-PDCCH is configured by a plurality of extended control channel elements (E-CCE; Enhanced CCE) and / or extended resource element groups (E-REG; Enhanced REG). Here, E-CCE is a unit constituting a control channel, and is composed of one or more resource elements or E-REG. The E-REG is composed of one or more resource elements. E-CCE is also referred to as eCCE. E-REG is also called eREG. The E-PDCCH is also referred to as ePDCCH.

  The second control channel region is composed of a plurality of E-CCEs. The number of E-CCEs in the second control channel region is defined by a predetermined value. In addition, the number of E-CCEs in the second control channel region may be implicitly determined according to control information related to the second control channel set by the base station 100. For example, the number of E-CCEs in the second control channel region may be determined by the number of PRB pairs in the second control channel region set by the base station 100. In addition, the number of E-CCEs in the second control channel region may be explicitly determined by control information regarding the second control channel set by the base station 100.

  Moreover, E-CCE is comprised by one or more E-REG (Enhanced Resource Element Group). Here, E-REG is used to define a resource that maps a control channel to a resource element. The E-REG is composed of one or more resource elements in one RB pair. Note that the E-REG may be configured with a plurality of resource elements across a plurality of RB pairs. For example, the E-REG may be configured with a plurality of resource elements in a plurality of RB pairs in the second control channel region. For example, E-REG may be comprised by the some resource element in the some RB pair which comprises E-CCE. A predetermined value is used as the number of E-REGs constituting one E-CCE. In addition, the number of E-REGs constituting one E-CCE may be determined implicitly by control information regarding the second control channel set by the base station 100. For example, the number of E-REGs constituting one E-CCE may be determined by a second control channel region mapping method (for example, local mapping or distributed mapping) set by the base station 100. Further, for example, the number of E-REGs constituting one E-CCE is the mapping method of E-CCE and terminal-specific reference signal set by the base station 100 (mapping (association between E-CCE and antenna port). ) Method). In addition, the number of E-REGs constituting one E-CCE may be explicitly determined by control information regarding the second control channel set by the base station 100.

  Here, in the RB pair, a plurality of mapping rules (mapping method, association) between E-REG and E-CCE are defined. One mapping method between E-REG and E-CCE is distributed mapping (distributed mapping rule). In the distributed mapping rule, mapping can be performed so as to be distributed to a plurality of RB pairs. In the case of distributed mapping, part or all of the E-REGs constituting each E-CCE can be mapped to E-REGs in a plurality of RB pairs. In the case of distributed mapping, part or all of the E-REGs constituting the RB pair can be mapped from E-REGs in a plurality of E-CCEs. Moreover, one of the mapping methods of E-REG which comprises RB pair, and E-REG which comprises E-CCE is localized mapping (local mapping rule). In the local mapping rule, each E-CCE can be locally mapped to one RB pair or a plurality of RB pairs arranged consecutively in the frequency direction. In the case of local mapping, all of the E-REGs constituting the E-CCE can be mapped to the E-REGs in one RB pair. In the case of local mapping, part or all of the E-REGs constituting the RB pair can be mapped from all of the E-REGs in a plurality of RB pairs that are continuously arranged in the frequency direction. In the local mapping and / or distributed mapping, a case where each E-CCE is composed of one or more E-REGs will be described. However, E-REG is not defined and each E-CCE is one. The same applies to the case of the above RB pair.

  In addition, the number of E-REGs constituting one RB pair is defined by a predetermined value. In addition, the number of E-REGs constituting one RB pair may be determined implicitly by control information regarding the second control channel set by the base station 100. For example, the number of E-REGs constituting one RB pair may be determined by a second control channel region mapping method (for example, local mapping or distributed mapping) set by the base station 100. Further, for example, the number of E-REGs constituting one RB pair depends on a mapping method between E-CCE and terminal-specific reference signal set by base station 100 (a mapping method between E-CCE and antenna port). It may be determined. In addition, the number of E-REGs constituting one E-CCE may be explicitly determined by control information regarding the second control channel set by the base station 100.

  From the above, the method for mapping the E-PDCCH to the PRB pair for the terminal 200 by the base station 100 is as follows. First, the E-PDCCH is mapped to one or more E-CCEs. Next, in the case of distributed mapping, a plurality of E-REGs constituting the E-CCE are mapped to E-REGs in a plurality of RB pairs. In the case of local mapping, a plurality of E-REGs constituting an E-CCE are mapped to E-REGs in one RB pair or a plurality of RB pairs arranged continuously in the frequency direction. Next, the plurality of RB pairs to which the E-REG is mapped are mapped to a part or all of the plurality of PRB pairs constituting the second control channel region.

  Here, for the numbering of the RB pairs used as the second control channel region, various methods can be used. The numbering of the RB pairs used as the second control channel region is performed according to a predetermined rule. For example, the number of the RB pair used as the second control channel region may be set in order from the lowest frequency.

  On the other hand, an E-CCE recognition method for detecting the E-PDCCH notified from the base station 100 by the terminal 200 is as follows. First, terminal 200 recognizes the PRB pair in the second control channel region set from base station 100 as an RB pair used as the second control channel region. Next, terminal 200 recognizes an E-REG or resource element constituting the E-CCE in each of the RB pairs used as the second control channel region. Next, terminal 200 recognizes E-CCE based on the recognized E-REG or resource element depending on whether the E-PDCCH is subjected to local mapping or distributed mapping. Further, terminal 200 performs E-PDCCH detection processing (blind decoding) based on the recognized E-CCE. As a method of E-PDCCH detection processing, a method described later is used.

  Hereinafter, the association (mapping) between the RB pair used as the second control channel region and the E-CCE will be described.

  FIG. 5 is a diagram illustrating an example in which the number of E-REGs configured by one RB pair is 16, and E-PDCCH is distributed mapped. In this example, the number of RB pairs in the second control channel region is four. The number of E-REGs constituting one E-CCE is four. In that case, the total number of E-REGs in the second control channel region is 64. The total number of E-CCEs in the second control channel region is 16. Further, each E-REG constituting one E-CCE is associated with an E-REG in a different RB pair. Specifically, E-REG1-1, E-REG1-2, E-REG1-3, and E-REG1-4 configuring E-CCE1 are associated with RB1, RB2, RB3, and RB4, respectively. On the other hand, each E-REG configured in one RB pair is associated from an E-REG in a different E-CCE. Specifically, the 16 E-REGs configured in RB1 are E-REG1-1, E-REG2-1, E-REG3-1, E-REG4-1, and E-CCE1-16. E-REG5-1, E-REG6-1, E-REG7-1, E-REG8-1, E-REG9-1, E-REG10-1, E-REG11-1, E-REG12-1, E- REG13-1, E-REG14-1, E-REG15-1, and E-REG16-1.

  FIG. 6 is a diagram illustrating an example in which the number of E-REGs configured by one RB pair is 16, and the E-PDCCH is locally mapped. In this example, the number of RB pairs in the second control channel region is four. The number of E-REGs constituting one E-CCE is four. In that case, the total number of E-REGs in the second control channel region is 64. The total number of E-CCEs in the second control channel region is 16. Further, all E-REGs constituting one E-CCE are associated with the E-REGs in the same RB pair. Specifically, E-REG1-1, E-REG1-2, E-REG1-3, and E-REG1-4 configuring E-CCE1 are associated with RB1. On the other hand, an E-REG composed of one RB pair is associated with the E-REGs constituting a plurality of E-CCEs. Specifically, the 16 E-REGs constituting RB1 are E-REG1-1, E-REG1-2, E-REG1-3, E-REG1-4, E, constituting E-CCE1-4. -REG2-1, E-REG2-2, E-REG2-3, E-REG2-4, E-REG3-1, E-REG3-2, E-REG3-3, E-REG3-4, E-REG4 -1, E-REG4-2, E-REG4-3, E-REG4-4.

  FIG. 7 is a diagram illustrating an example in which the number of E-REGs configured by one RB pair is 8, and E-PDCCH is distributed mapped. In this example, the number of RB pairs in the second control channel region is two. The number of E-REGs constituting one E-CCE is two. In that case, the total number of E-REGs in the second control channel region is 16. The total number of E-CCEs in the second control channel region is 8. Further, each E-REG constituting one E-CCE is associated with an E-REG in a different RB pair. Specifically, E-REG1-1 and E-REG1-2 configuring E-CCE1 are associated with RB1 and RB2, respectively. On the other hand, each E-REG configured in one RB pair is associated from an E-REG in a different E-CCE. Specifically, the eight E-REGs configured in RB1 are E-REG1-1, E-REG2-1, E-REG3-1, E-REG4-1, and E-CCE1-8. It is related from E-REG5-1, E-REG6-1, E-REG7-1, and E-REG8-1. In FIG. 7, the case where the number of RB pairs used as the second control channel region is two has been described. For example, when the number of RB pairs used as the second control channel region is 4, the second control is performed so that E-PDCCH having an aggregation level of 2 or more is distributed and mapped to the four RB pairs. An association between the E-REG in the RB pair used as the channel region and the E-REG for the E-CCE can be defined.

  FIG. 8 is a diagram illustrating an example in which the number of E-REGs configured by one RB pair is 8 and E-PDCCH is locally mapped. In this example, the number of RB pairs in the second control channel region is two. The number of E-REGs constituting one E-CCE is two. In that case, the total number of E-REGs in the second control channel region is 16. The total number of E-CCEs in the second control channel region is 8. Further, all E-REGs constituting one E-CCE are associated with the E-REGs in the same RB pair. Specifically, E-REG1-1 and E-REG1-2 configuring E-CCE1 are associated with RB1. On the other hand, an E-REG composed of one RB pair is associated with the E-REGs constituting a plurality of E-CCEs. Specifically, the eight E-REGs constituting RB1 are E-REG1-1, E-REG2-1, E-REG3-1, E-REG4-1, E, constituting E-CCE1-4. -Associated with REG1-2, E-REG2-2, E-REG3-2, E-REG4-2.

  Next, details of the configuration of the E-REG configured with one RB pair will be described. The E-REG used between the base station 100 and the terminal 200 is assigned a number for identifying the E-REG. E-REG numbering is performed based on a predetermined rule. Various methods can be used for the rules used for E-REG numbering. Further, the numbered E-REG numbers are associated with the E-REGs constituting the RB pair described in FIGS. Moreover, the E-REG number which comprises one RB pair can be used in common by distributed mapping and local mapping. Moreover, it is preferable that the E-REG numbering is performed in consideration of each of the distributed mapping and the local mapping. In the following, the E-REG numbering rule for one RB pair will be described, but it can also be applied to E-REG numbering performed across a plurality of RB pairs.

  Here, in E-REG numbering, resource elements to which terminal-specific reference signals, cell-specific reference signals, transmission path condition measurement reference signals and / or broadcast channels are mapped are numbered as they are (punctured). May be performed. That is, E-REG numbering is performed over the entire resource elements in the RB pair without depending on the signal mapped to the resource elements. Terminal 200 recognizes that a control channel is not mapped to a resource element to which a terminal-specific reference signal, a cell-specific reference signal, a transmission path condition measurement reference signal, and / or a broadcast channel are mapped. Thereby, since the definition of E-REG is determined without depending on the signal mapped to the resource element, the processing and storage capacity in the base station 100 and the terminal 200 can be reduced.

  Here, in E-REG numbering, a resource element to which a cell-specific reference signal, a transmission path condition measurement reference signal, and / or a broadcast channel are mapped may be numbered as it is (punctured). . Also, E-REG numbering is performed considering only resource elements to which terminal-specific reference signals are mapped. For example, E-REG numbering is performed by skipping only resource elements to which terminal-specific reference signals are mapped (rate matching). That is, E-REG numbering is performed over the entire resource elements in the RB pair without depending on signals mapped to the resource elements, except for terminal-specific reference signals. Terminal 200 recognizes that a control channel is not mapped to a resource element to which a terminal-specific reference signal, a cell-specific reference signal, a transmission path condition measurement reference signal, and / or a broadcast channel are mapped. Thereby, since the definition of E-REG is determined without depending on the signal mapped to the resource element except for the terminal-specific reference signal, the processing and storage capacity in the base station 100 and the terminal 200 can be reduced. . Further, when the second control channel is demodulated using the terminal-specific reference signal, the terminal-specific reference signal is mapped to the RB pair to which the second control channel is mapped. Therefore, the second control channel can be mapped in consideration of resource overhead due to the terminal-specific reference signal.

  Here, in E-REG numbering, resource elements to which terminal-specific reference signals, cell-specific reference signals, transmission path condition measurement reference signals and / or broadcast channels are mapped are skipped (rate-matched) numbers. You may do it. That is, E-REG numbering is applied to all resource elements in an RB pair, except for resource elements to which terminal-specific reference signals, cell-specific reference signals, transmission path condition measurement reference signals and / or broadcast channels are mapped. Done across. Thereby, the second control channel can be mapped in consideration of the resource overhead due to the terminal-specific reference signal, the cell-specific reference signal, the transmission path condition measurement reference signal, and / or the broadcast channel.

FIG. 9 is a diagram illustrating an example of the configuration of the E-REG. This figure shows four RB pairs (n _RB = 1, 2, 3, 4) used as the second control channel region when the number of E-REGs constituting one RB pair is 16. Yes. Further, the RB pair shown in FIG. 9 is associated with the RB pair shown in FIGS. In each RB pair, the first half slot 0 and the second half slot 1 are each composed of seven OFDM symbols with OFDM symbol numbers 0 to 6. In each RB pair, 16 E-REGs are defined. In each RB pair, a set of resource elements indicated by 0 to 15 constitutes an independent E-REG. For example, a set of resource elements indicated by 0 in RB1, a set of resource elements indicated by 0 in RB2, a set of resource elements indicated by 0 in RB3, and a set of resource elements indicated by 0 in RB4 These are independent E-REGs. Further, the number indicated in each resource element may be an E-REG number. That is, E-REG0 to E-REG15 are shown in each RB. Here, since the E-REG number is added for the following explanation, another number may be added. For example, as shown in FIG. 9, numbering may be performed using a method other than numbering 0 to 15 in each RB pair. For example, E-REG numbers may be added differently through RB pairs used as the second control channel region. Further, the order of the RB pairs used as the second control channel region can be made arbitrary with respect to the frequency direction. Further, even when the number of RB pairs used as the second control channel region exceeds 4, each RB pair can similarly use the E-REG configuration, but the E-REG associated with one E-CCE. Can use four RBs as a unit.

FIG. 10 is a diagram illustrating an example of the configuration of the E-REG. This figure shows four RB pairs (n _RB = 1, 2) used as the second control channel region when the number of E-REGs constituting one RB pair is eight. Further, the RB pair shown in FIG. 10 is associated with the RB pair shown in FIGS. In each RB pair, the first half slot 0 and the second half slot 1 are each composed of seven OFDM symbols with OFDM symbol numbers 0 to 6. In each RB pair, 8 E-REGs are defined. In each RB pair, a set of resource elements indicated by 0 to 7 constitutes an independent E-REG. For example, the set of resource elements indicated by 0 in RB1 and the set of resource elements indicated by 0 in RB2 are independent E-REGs. Further, the number indicated in each resource element may be an E-REG number. That is, E-REG0 to E-REG7 are shown in each RB. Here, since the E-REG number is added for the following explanation, another number may be added. For example, as shown in FIG. 10, numbering may be performed using a method other than numbering 0 to 7 in each RB pair. For example, E-REG numbers may be added differently through RB pairs used as the second control channel region. Further, the order of the RB pairs used as the second control channel region can be made arbitrary with respect to the frequency direction. Further, even when the number of RB pairs used as the second control channel region exceeds 2, each RB pair can similarly use the E-REG configuration, but the E-REG associated with one E-CCE. Can use two RBs as a unit.

  Here, in each RB pair, a set of resource elements represented by subcarrier numbers 0 to 5 and OFDM symbol numbers 0 to 6 in slot 0 is RE set A, and subcarrier numbers 6 to 11 and OFDM in slot 0 are set. A set of resource elements represented by symbol numbers 0 to 6 is RE set B, a set of resource elements represented by subcarrier numbers 0 to 5 and OFDM symbol numbers 0 to 6 in slot 1 is RE set C, and A set of resource elements represented by carrier numbers 6 to 11 and OFDM symbol numbers 0 to 6 in slot 1 is referred to as RE set D.

  In the E-REG configuration shown in FIG. 9, the E-REG configuration in RE set A of RB1 is the same as the E-REG configuration in RE set D of RB2. The E-REG configuration in the RB1 RE set B is the same as the E-REG configuration in the RB2 RE set C. Further, the E-REG configuration in RE set C of RB1 is the same as the E-REG configuration in RE set B of RB2. The E-REG configuration in the RB1 RE set D is the same as the E-REG configuration in the RB2 RE set A. The E-REG configuration in the RB3 RE set A is the same as the E-REG configuration in the RB4 RE set D. The E-REG configuration in RE set B of RB3 is the same as the E-REG configuration in RE set C of RB4. The E-REG configuration in RE set C of RB3 is the same as the E-REG configuration in RE set B of RB4. The E-REG configuration in the RB3 RE set D is the same as the E-REG configuration in the RB4 RE set A.

  In the E-REG configuration shown in FIG. 10, the E-REG configuration in RE set A of RB1 is the same as the E-REG configuration in RE set D of RB2. The E-REG configuration in the RB1 RE set B is the same as the E-REG configuration in the RB2 RE set C. Further, the E-REG configuration in RE set C of RB1 is the same as the E-REG configuration in RE set B of RB2. The E-REG configuration in the RB1 RE set D is the same as the E-REG configuration in the RB2 RE set A.

FIG. 11 is an example of a mathematical formula for obtaining the E-REG number and the E-CCE number in the RB pair used as the second control channel region. FIG. 11 illustrates a case where an E-REG number is associated with each RB pair illustrated in FIGS. 9 and 10. n E-REG number n _eREG ^(nRB) in resource element (k, l) of n _RB , E-CCE number n _{eCCE_D} in the second control channel region based on n _eREG ^(nRB ), n _{eCCE_L} (in case of local mapping) is indicated.

However, N _sc ^RB is the number of subcarriers in one RB. For example, in the examples of FIGS. 9 and 10, N _sc ^RB is 12. N _eREG ^RB is the number of E- _{REGs in} one RB. For example, in the example of FIG. 9, N _eREG ^RB is 16 and in the example of FIG. 10, N _eREG ^RB is 8. N _{eCCE_L} ^RB is the number of E-CCEs in one RB in the local mapping. For example, in the example of FIG. 9 and FIG. 10, 4 is used for _{NeCCE_L} ^RB . n _s indicates a slot number, which is a number (n _s = 0, 1,..., 19) in a radio frame composed of 10 subframes (20 slots). That is, the even-numbered slot number slot corresponds to a slot composed of the first seven OFDM symbols in the subframe, and corresponds to slot 0 shown in FIGS. The slot with an odd slot number corresponds to a slot composed of the last seven OFDM symbols in the subframe, and corresponds to slot 1 shown in FIGS. mod (x, y) indicates the remainder of dividing x by y. floor (x) indicates the maximum natural number not exceeding x. n _any is any natural number. Further, the E-REG number may be configured to shift with respect to the subcarrier number as the OFDM symbol number increases. n _shift indicates the number of shifts. For example, by setting n _shift to 1 and n _any to 0, an E-REG configuration as shown in FIGS. 9 and 10 can be obtained.

FIG. 12 is an example of a mathematical formula for obtaining an E-REG number and an E-CCE number in an RB pair used as the second control channel region. FIG. 12 illustrates a case where different E-REG numbers are associated with each other over RB pairs used as the second control channel region. and E-REG numbers n _eREG in resource elements _{n RB (k, l),} ( for distributed mapping) E-CCE number n _{ECCE_D} in the second control channel region based on the _{n eREG,} n eCCE_L (For localized mapping ) And is shown.

  Hereinafter, in each RB, the resource element indicated by the kth subcarrier and the lth OFDM symbol is represented as (k, l). Further, a set of resource elements constituting one E-REG is indicated by <(k, l)>. In FIG. 9 and FIG. 10, an index (l = 0, 1,..., 6) is assigned to each OFDM symbol in the time direction with respect to 7 OFDM symbols in each slot of each RB pair. The 9 and 10, an index (k = 0, 1,..., 11) is assigned to each subcarrier in the frequency direction with respect to 12 subcarriers in each RB pair.

  Here, the E-REG shown in FIG. 9 will be described in detail. Note that the E-REG number described below is an E-REG number when given for each RB pair, but the E-REG number when given differently for the RB pair used as the second control channel region. The same applies to the -REG number. As shown in FIG. 9, in each RB pair, one slot may be configured with E-REG numbers 0-7, and the other slot may be configured with E-REG numbers 8-15. Of the four RB pairs, two RB pairs (RB1 and RB3 in the example of FIG. 9) are configured such that slot 0 includes E-REG numbers 0 to 7, and slot 1 includes E-REG numbers 8 to 15. May consist of: Of the four RB pairs, two RB pairs (RB2 and RB4 in the example of FIG. 9) are configured such that slot 1 is configured with E-REG numbers 0 to 7, and slot 0 is configured with E-REG numbers 8 to 15. May be.

Further, as shown in FIG. 9, in each OFDM symbol, an arbitrary E-REG number is an RB pair (in the example of FIG. 9) used as an E-REG associated with one E-CCE in the case of distributed mapping. , RB1 to RB4), which may be the same number. In each OFDM symbol, it may be preferable that each E-REG number is the same number of RB pairs used as the second control channel region. Further, in each OFDM symbol, the number of resource elements of each E-REG number is the number of RB pairs (RB1 in the example of FIG. 9) used as an E-REG associated with one E-CCE in the case of distributed mapping. ~ RB4), it may be 4 * N _sc ^RB / N _eREG ^RB . For example, in the example of FIG. 9, in RB1 to RB4, E-REGs 0 to 15 in OFDM symbol number 0 of slot 0 are associated with three resource elements, respectively.

Also, as shown in FIG. 9, the configuration (order, sequence, arrangement) of E-REG in an arbitrary OFDM symbol is cyclically in units of subcarriers in the frequency direction between one or more RB pairs. It may shift (cyclic shift). For example, in the example of FIG. 9, in RB1 and RB3 of slot 0, the E-REG configuration configured by E-REG0 to 7 is cyclically shifted in the frequency direction in units of subcarriers. In each slot, the configuration of E-REG in an arbitrary OFDM symbol may be cyclically shifted by an arbitrary number of shifts as the OFDM symbol number increases. That is, an arbitrary E-REG number may be cyclically shifted by an arbitrary number of shifts as the OFDM symbol number increases. Here, the number of shifts for the OFDM symbol corresponds to n _shift in FIGS. For example, in the example of FIG. 9, in each slot, the configuration of E-REG in an arbitrary OFDM symbol is cyclically shifted by one shift number as the OFDM symbol number increases. That is, an arbitrary E-REG number is cyclically shifted by a shift number of 1 in the direction in which the subcarrier number increases as the OFDM symbol number increases. Also, any natural number can be used as the number of shifts for this OFDM symbol. For example, if the shift number for the OFDM symbol is a positive value, an arbitrary E-REG number may be cyclically shifted in a direction in which the subcarrier number increases as the OFDM symbol number increases. For example, if the shift number for the OFDM symbol is a negative value, an arbitrary E-REG number may be cyclically shifted in a direction in which the subcarrier number decreases as the OFDM symbol number increases. For example, if the number of shifts for the OFDM symbol is 0, the E-REG number for each subcarrier may be one.

Also, as shown in FIG. 9, in each RB pair, the E-REG numbers of arbitrary resource elements (k, l) may all be the same. For example, the remainder when the E-REG numbers at (0,0) of ^RB1 to _RB4 are divided by _NeCCE ^RB is all zero. Further, as shown in FIG. 9, in each subcarrier, the remainder when the E-REG number of the last OFDM symbol of slot 0 (OFDM symbol number 6 in slot 0) is divided by _NeCCE ^RB , and slot 1 The remainder when the E-REG number of the first OFDM symbol (OFDM symbol number 1 in slot 1) is divided by _NeCCE ^RB may be the same. That is, for an arbitrary subcarrier number k, the remainder when (k, 6) E-REG number in slot 0 is divided by _NeCCE ^RB and the E-REG number of (k, 0) in slot 1 The remainder when divided by _eCCE ^RB may all be the same.

For example, as shown in FIG. 9, the resource elements of E-REG0 ( _neREG = 0) in each RB are associated as follows. E-REG0 in RB1 (n _RB = 1) is a set of 11 resource elements in Slot0 <(0,0), (1,1), (2,2), (3,3), (4, 4), (5,5), (6,6), (8,0), (9,1), (10,2), (11,3)>. E-REG0 in RB2 (n _RB = 2) is a set of 11 resource elements in Slot1 <(0,6), (2,0), (3,1), (4,2), (5, 3), (6,0), (7,1), (8,2), (9,3), (10,4), (11,5)>. E-REG0 in RB3 (n _RB = 3) is a set of 10 resource elements in Slot0 <(0,4), (1,5), (2,6), (4,0), (5, 1), (6,2), (7,3), (8,4), (9,5), (10,6)>. E-REG0 in RB4 (n _RB = 4) is a set of 10 resource elements in Slot1 <(0,2), (1,3), (2,4), (3,5), (4, 6), (6,4), (7,5), (8,6), (10,0), (11,1)>.

  Here, the E-REG shown in FIG. 10 will be described in detail. Note that the E-REG number described below is an E-REG number when given for each RB pair, but the E-REG number when given differently for the RB pair used as the second control channel region. The same applies to the -REG number. As shown in FIG. 10, in each RB pair, one slot may be configured with E-REG numbers 0 to 3 and the other slot may be configured with E-REG numbers 4 to 7. Of the two RB pairs, one RB pair (RB1 in the example of FIG. 10) has slot 0 configured with E-REG numbers 0 to 3, and slot 1 configured with E-REG numbers 4 to 7. May be. Of the two RB pairs, in the other RB pair (RB2 in the example of FIG. 10), slot 1 is configured with E-REG numbers 0 to 3, and slot 0 is configured with E-REG numbers 4 to 7. It may be.

Also, as shown in FIG. 10, in each OFDM symbol, an arbitrary E-REG number is an RB pair used as an E-REG associated with one E-CCE in the case of distributed mapping (in the example of FIG. 10). , RB1 to RB2), which may be the same number. In each OFDM symbol, it may be preferable that each E-REG number is the same number of RB pairs used as the second control channel region. In each OFDM symbol, the number of resource elements of each E-REG number is the number of RB pairs (RB1 in the example of FIG. 10) used as an E-REG associated with one E-CCE in the case of distributed mapping. ~ RB2), it may be 4 * N _sc ^RB / N _eREG ^RB . For example, in the example of FIG. 10, in RB1 to RB2, E-REGs 0 to 7 in OFDM symbol number 0 of slot 0 are each associated with three resource elements.

Also, as shown in FIG. 10, the configuration (order, sequence, arrangement) of E-REG in an arbitrary OFDM symbol is cyclically in units of subcarriers in the frequency direction between one or more RB pairs. It may shift (cyclic shift). For example, in the example of FIG. 10, in RB1 of slot 0, the E-REG configuration composed of E-REG0 to 3 is cyclically shifted in units of subcarriers in the frequency direction. In each slot, the configuration of E-REG in an arbitrary OFDM symbol may be cyclically shifted by an arbitrary number of shifts as the OFDM symbol number increases. That is, an arbitrary E-REG number may be cyclically shifted by an arbitrary number of shifts as the OFDM symbol number increases. Here, the number of shifts for the OFDM symbol corresponds to n _shift in FIGS. For example, in the example of FIG. 10, in each slot, the E-REG configuration in an arbitrary OFDM symbol is cyclically shifted by a shift number of 1 as the OFDM symbol number increases. That is, an arbitrary E-REG number is cyclically shifted by a shift number of 1 in the direction in which the subcarrier number increases as the OFDM symbol number increases. Also, any natural number can be used as the number of shifts for this OFDM symbol. For example, if the shift number for the OFDM symbol is a positive value, an arbitrary E-REG number may be cyclically shifted in a direction in which the subcarrier number increases as the OFDM symbol number increases. For example, if the shift number for the OFDM symbol is a negative value, an arbitrary E-REG number may be cyclically shifted in a direction in which the subcarrier number decreases as the OFDM symbol number increases. For example, if the number of shifts for the OFDM symbol is 0, the E-REG number for each subcarrier may be one.

Also, as shown in FIG. 10, in each RB pair, the E-REG numbers of arbitrary resource elements (k, l) may all be the same. For example, the remainder when the E-REG numbers at (0,0) of _{RB1 and} ^RB2 are divided by _NeCCE ^RB is all zero. Also, as shown in FIG. 10, in each subcarrier, the remainder when the E-REG number of the last OFDM symbol in slot 0 (OFDM symbol number 6 in slot 0) is divided by _NeCCE ^RB , and slot 1 The remainder when the E-REG number of the first OFDM symbol (OFDM symbol number 1 in slot 1) is divided by _NeCCE ^RB may be the same. That is, for an arbitrary subcarrier number k, the remainder when (k, 6) E-REG number in slot 0 is divided by _NeCCE ^RB and the E-REG number of (k, 0) in slot 1 The remainder when divided by _eCCE ^RB may all be the same.

For example, as shown in FIG. 10, the resource elements of E-REG0 ( _neREG = 0) in each RB are associated as follows. E-REG0 in RB1 (n _RB = 1) is a set of 21 resource elements in Slot0 <(0,0), (4,0), (8,0), (1,1), (5, 1), (9,1), (2,2), (6,2), (10,2), (3,3), (7,3), (11,3), (0,4) , (4,4), (8,4), (1,5), (5,5), (9,5), (2,6), (6,6), (10,6)> Associated. E-REG0 in RB2 (n _RB = 2) is a set of 21 resource elements in Slot1 <(2,0), (6,0), (10,0), (3,1), (7, 1), (11,1), (0,2), (4,2), (8,2), (1,3), (5,3), (9,3), (2,4) , (6,4), (10,4), (3,5), (7,5), (11,5), (0,6), (4,6), (8,6)> Associated.

  The E-REG configuration shown in FIGS. 9 and 10 is an example, and the present invention is not limited to this. For example, the E-REG number is increased and cyclically shifted as the subcarrier number increases, but the E-REG number is decreased and cyclically shifted as the subcarrier number increases. It may be configured as follows. That is, in the formulas for obtaining the E-REG numbers in FIG. 10 and FIG. 11, k may be replaced with k ″, and the formula of k ″ = − 1 * (k−11) may be further added. Note that the present invention can be similarly applied to an E-REG configuration or an E-CCE configuration described below.

11 and 12, the case where the subcarrier number given for each RB pair is used has been described. However, the present invention is not limited to this. For example, the subcarrier number may be given differently over the system bandwidth (component carrier). Specifically, it can be realized by further adding k = mod (k ″, N _sc ^RB ) to the mathematical formulas for obtaining the E-REG numbers shown in FIGS. Here, k ″ is a subcarrier number given differently over the system bandwidth. Note that the present invention can be similarly applied to an E-REG configuration or an E-CCE configuration described below.

  The E-REGs shown in FIG. 9 are associated with the E-REGs constituting the RB pair shown in FIGS. For example, when using distributed mapping, E-REG0 to E-REG15 shown in FIG. 9 are respectively E-REG1-1, E-REG2-1, E-REG3-1, E-REG4-1 shown in FIG. E-REG5-1, E-REG6-1, E-REG7-1, E-REG8-1, E-REG9-1, E-REG10-1, E-REG11-1, E-REG12-1, E- It is associated with REG13-1, E-REG14-1, E-REG15-1, E-REG16-1. When using local mapping, E-REG0 to E-REG15 shown in FIG. 9 are respectively E-REG1-1, E-REG2-1, E-REG3-1, E-REG4-1 shown in FIG. E-REG1-2, E-REG2-2, E-REG3-2, E-REG4-2, E-REG1-3, E-REG2-3, E-REG3-3, E-REG4-3, E- It is associated with REG1-4, E-REG2-4, E-REG3-4, E-REG4-4.

  The E-REGs shown in FIG. 10 are respectively associated with the E-REGs that make up the RB pair shown in FIGS. For example, when using distributed mapping, E-REG0 to E-REG7 shown in FIG. 10 are respectively E-REG1-1, E-REG2-1, E-REG3-1, E-REG4-1 shown in FIG. It is associated with E-REG5-1, E-REG6-1, E-REG7-1, and E-REG8-1. When local mapping is used, E-REG0 to E-REG7 shown in FIG. 10 are respectively E-REG1-1, E-REG2-1, E-REG3-1, E-REG4-1 shown in FIG. It is associated with E-REG1-2, E-REG2-2, E-REG3-2, and E-REG4-2.

As shown in FIGS. 5 and 7, the E-REGs constituting the E-CCE are distributed and mapped to a plurality of RB pairs. As shown in FIGS. 6 and 8, the E-REGs constituting the E-CCE are locally mapped to one RB pair. Here, the E-REG configuration shown in FIGS. 9 and 10 can be commonly used in distributed mapping and local mapping. Further, as shown in FIGS. 11 and 12, E-CCE number n _{ECCE_L} in E-CCE number n _{ECCE_D} and localized mapping in a distributed mapping may respectively be obtained on the basis of the E-REG numbers.

When the E-REG number is associated with each RB pair, the E-CCE in the distributed mapping is associated with a plurality of E-REGs having the same E-REG number as illustrated in FIG. For example, for example, as shown in FIG. 10, when N _eREG ^RB is 8, E-CCE0 (n _{eCCE_D} = 0) in distributed mapping is two E-REGs (E-REG0 in RB1, RB2) E-REG0).

Further, over the RB pair to be used as the second control channel region, when the different E-REG numbers associated, the E-CCE in a distributed mapping, as shown in FIG. 12, N _eREG the E-REG numbers It is associated with a plurality of E-REGs that have the same remainder when divided by ^RB . For example, when N _eREG ^RB is 16 as shown in FIG. 9, E-CCE0 ( _{neCCE_D} = 0) in distributed mapping is four E-REGs (E-REG0 in RB1, E-REG16 in RB2, E-REG32 in RB3 and E-REG48 in RB4). Further, for example, as shown in FIG. 10, when N _eREG ^RB is 8, E-CCE0 (n _{eCCE_D} = 0) in distributed mapping is two E-REGs (E-REG0 in RB1 and E-REG in RB2). REG16).

FIG. 13 is a diagram illustrating an example of the configuration of the E-REG. This figure shows an RB pair used as the second control channel region when the number of E-REGs constituting one RB pair is 16. Further, the E-REG configuration shown in FIG. 13 is used in all RB pairs used as the second control channel region. Here, as an example, it is assumed that four RB pairs (n _RB = 1, 2, 3, 4) used as the second control channel region are used. Further, the RB pair shown in FIG. 13 is associated with the RB pair shown in FIGS. In each RB pair, the first half slot 0 and the second half slot 1 are each composed of seven OFDM symbols with OFDM symbol numbers 0 to 6. In each RB pair, 16 E-REGs are defined. In each RB pair, the set of resource elements indicated by 1 to 16 constitutes an independent E-REG. For example, a set of resource elements indicated by 0 in RB1, a set of resource elements indicated by 0 in RB2, a set of resource elements indicated by 0 in RB3, and a set of resource elements indicated by 0 in RB4 These are independent E-REGs. Further, the number indicated in each resource element may be an E-REG number. That is, E-REG0 to E-REG15 are shown in each RB. Here, since the E-REG number is added for the following explanation, another number may be added. For example, as shown in FIG. 13, numbering may be performed using a method other than numbering 0 to 15 in each RB pair. For example, E-REG numbers may be added differently through RB pairs used as the second control channel region. Further, the order of the RB pairs used as the second control channel region can be made arbitrary with respect to the frequency direction. Further, even when the number of RB pairs used as the second control channel region exceeds 4, each RB pair can similarly use the E-REG configuration, but the E-REG associated with one E-CCE. Can use four RBs as a unit.

  Here, the E-REG configuration shown in FIG. 13 will be described. A part of E-REG0 to E-REG15 is associated with the resource element of each OFDM symbol. Furthermore, as the OFDM symbol number increases, the E-REG number associated with the frequency direction shifts cyclically. The number of shifts that cyclically shift can be constant with respect to the OFDM symbol number. Moreover, E-REG comprised by the cyclic shift can be comprised independently in each slot. The E-REG number of the last OFDM symbol in slot 0 (OFDM symbol number 6 in slot 0) and the E-REG number of the first OFDM symbol in slot 1 (OFDM symbol number 0 in slot 1) are respectively Can be the same in the subcarriers.

  For example, as an example of the E-REG configuration, as shown in FIG. 13, E-REG0 to E-REG15 are associated with each RB pair. E-REG0 is a set of resource elements in slot 0 <(0,0), (1,1), (2,2), (3,3), (4,4), (5,5), ( 6,6)> and the set of resource elements in slot 1 <(6,0), (7,1), (8,2), (9,3), (10,4), (11,5) Associated with>. E-REG1 is a set of resource elements in slot 0 <(1,0), (2,1), (3,2), (4,3), (5,4), (6,5), ( 7,6)> and the resource element set <(7,0), (8,1), (9,2), (10,3), (11,4)> in slot 1. E-REG2 is a set of resource elements in slot 0 <(2,0), (3,1), (4,2), (5,3), (6,4), (7,5), ( 8,6)> and the resource element set <(8,0), (9,1), (10,2), (11,3)> in slot 1. E-REG3 is a set of resource elements in slot 0 <(3,0), (4,1), (5,2), (6,3), (7,4), (8,5), ( 9,6)> and the resource element set <(9,0), (10,1), (11,2)> in slot 1. E-REG4 is a set of resource elements in slot 0 <(4,0), (5,1), (6,2), (7,3), (8,4), (9,5), ( 10,6)> and the resource element set <(10,0), (11,1), (0,6)> in slot 1. E-REG5 is a set of resource elements in slot 0 <(5,0), (6,1), (7,2), (8,3), (9,4), (10,5), ( 11,6)> and the resource element set <(11,0), (0,5), (1,6)> in slot 1. E-REG6 is a set of resource elements in slot 0 <(6,0), (7,1), (8,2), (9,3), (10,4), (11,5)> , Associated with the set of resource elements <(0,4), (1,5), (2,6)> in slot 1. E-REG 7 is a set of resource elements in slot 0 <(7,0), (8,1), (9,2), (10,3), (11,4)> and resource elements in slot 1 Associated with the set <(0,3), (1,4), (2,5), (3,6)>. E-REG 8 includes a set of resource elements <(8,0), (9,1), (10,2), (11,3)> in slot 0 and a set of resource elements <(0, 2), (1,3), (2,4), (3,5), (4,6)>. The E-REG 9 includes a set of resource elements <(9,0), (10,1), (11,2)> in slot 0 and a set of resource elements <(0,1), (1, 2), (2,3), (3,4), (4,5), (5,6)>. The E-REG 10 includes a set of resource elements <(10,0), (11,1), (0,6)> in slot 0 and a set of resource elements <(0,0), (1, 1), (2,2), (3,3), (4,4), (5,5), (6,6)>. The E-REG 11 includes a set of resource elements in slot 0 <(11,0), (0,5), (1,6)> and a set of resource elements in slot 1 <(1,0), (2, 1), (3,2), (4,3), (5,4), (6,5), (7,6)>. The E-REG 12 includes a set of resource elements <(0,4), (1,5), (2,6)> in slot 0 and a set of resource elements <(2,0), (3, 1), (4,2), (5,3), (6,4), (7,5), (8,6)>. The E-REG 13 includes a set of resource elements <(0,3), (1,4), (2,5), (3,6)> in slot 0 and a set of resource elements in slot 1 <(3, 0), (4,1), (5,2), (6,3), (7,4), (8,5), (9,6)>. The E-REG 14 is a set of resource elements <(0,2), (1,3), (2,4), (3,5), (4,6)> in slot 0 and resource elements in slot 1 Is associated with the set <(4,0), (5,1), (6,2), (7,3), (8,4), (9,5), (10,6)>. E-REG 15 is a set of resource elements in slot 0 <(0,1), (1,2), (2,3), (3,4), (4,5), (5,6)> and , Set of resource elements in slot 1 <(5,0), (6,1), (7,2), (8,3), (9,4), (10,5), (11,6) Associated with>.

FIG. 14 is a diagram illustrating an example of the configuration of the E-REG. This figure shows an RB pair used as the second control channel region when the number of E-REGs constituting one RB pair is eight. Further, the E-REG configuration shown in FIG. 14 is used in all RB pairs used as the second control channel region. Here, as an example, it is assumed that two RB pairs (n _RB = 1, 2) used as the second control channel region are used. Further, the RB pair shown in FIG. 14 is associated with the RB pair shown in FIGS. In each RB pair, the first half slot 0 and the second half slot 1 are each composed of seven OFDM symbols with OFDM symbol numbers 0 to 6. In each RB pair, 8 E-REGs are defined. In each RB pair, a set of resource elements indicated by 0 to 7 constitutes an independent E-REG. For example, the set of resource elements indicated by 0 in RB1 and the set of resource elements indicated by 0 in RB2 are independent E-REGs. Further, the number indicated in each resource element may be an E-REG number. That is, E-REG0 to E-REG7 are shown in each RB. Here, since the E-REG number is added for the following explanation, another number may be added. For example, as shown in FIG. 14, numbering may be performed using a method other than numbering 0 to 7 in each RB pair. For example, E-REG numbers may be added differently through RB pairs used as the second control channel region. Further, the order of the RB pairs used as the second control channel region can be made arbitrary with respect to the frequency direction. Further, even when the number of RB pairs used as the second control channel region exceeds 2, each RB pair can similarly use the E-REG configuration, but the E-REG associated with one E-CCE. Can use two RBs as a unit.

  Here, the E-REG configuration shown in FIG. 14 will be described. E-REG0 to E-REG7 are associated with the resource elements of the respective OFDM symbols. Furthermore, as the OFDM symbol number increases, the E-REG number associated with the frequency direction shifts cyclically. The number of shifts that cyclically shift can be constant with respect to the OFDM symbol number. Moreover, E-REG comprised by the cyclic shift can be comprised independently in each slot. The E-REG number of the last OFDM symbol in slot 0 (OFDM symbol number 6 in slot 0) and the E-REG number of the first OFDM symbol in slot 1 (OFDM symbol number 0 in slot 1) are respectively Can be the same in the subcarriers.

  For example, as shown in FIG. 14, in an example of the E-REG configuration, E-REG0 to E-REG7 are associated with each RB pair. E-REG0 is a set of resource elements in slot 0 <(0,0), (1,1), (2,2), (3,3), (4,4), (5,5), ( 6,6), (8,0), (9,1), (10,2), (11,3)> and the set of resource elements in slot 1 <(0,2), (1,3) , (2,4), (3,5), (4,6), (6,0), (7,1), (8,2), (9,3), (10,4), ( 11,5)>. E-REG1 is a set of resource elements in slot 0 <(1,0), (2,1), (3,2), (4,3), (5,4), (6,5), ( 7,6), (9,0), (10,1), (11,2)> and the set of resource elements in slot 1 <(0,1), (1,2), (2,3) , (3,4), (4,5), (5,6), (7,0), (8,1), (9,2), (10,3), (11,4)> Associated. E-REG2 is a set of resource elements in slot 0 <(0,6), (2,0), (3,1), (4,2), (5,3), (6,4), ( 7,5), (8,6), (10,0), (11,1)> and the set of resource elements in slot 1 <(0,0), (1,1), (2,2) , (3,3), (4,4), (5,5), (6,6), (8,0), (9,1), (10,2), (11,3)> Associated. E-REG3 is a set of resource elements in slot 0 <(0,5), (1,6), (3,0), (4,1), (5,2), (6,3), ( 7,4), (8,5), (9,6), (11,0)> and the set of resource elements in slot 1 <(0,1), (1,2), (2,3) , (3,4), (4,5), (5,6), (7,0), (8,1), (9,2), (10,3), (11,4)> Associated. E-REG4 is a set of resource elements in slot 0 <(0,4), (1,5), (2,6), (4,0), (5,1), (6,2), ( 7,3), (8,4), (9,5), (10,6)> and the set of resource elements in slot 1 <(0,6), (2,0), (3,1) , (4,2), (5,3), (6,4), (7,5), (8,6), (10,0), (11,1)>. E-REG5 is a set of resource elements in slot 0 <(0,3), (1,4), (2,5), (3,6), (5,0), (6,1), ( 7,2), (8,3), (9,4), (10,5), (11,6)> and the set of resource elements in slot 1 <(0,5), (1,6) , (3,0), (4,1), (5,2), (6,3), (7,4), (8,5), (9,6), (11,0)> Associated. E-REG6 is a set of resource elements in slot 0 <(0,2), (1,3), (2,4), (3,5), (4,6), (6,0), ( 7,1), (8,2), (9,3), (10,4), (11,5)> and the set of resource elements in slot 1 <(0,4), (1,5) , (2,6), (4,0), (5,1), (6,2), (7,3), (8,4), (9,5), (10,6)> Associated. E-REG7 is a set of resource elements in slot 0 <(0,1), (1,2), (2,3), (3,4), (4,5), (5,6), ( 7,0), (8,1), (9,2), (10,3), (11,4)> and the set of resource elements in slot 1 <(0,3), (1,4) , (2,5), (3,6), (5,0), (6,1), (7,2), (8,3), (9,4), (10,5), ( 11,6)>.

FIG. 15 is an example of a mathematical formula for obtaining the E-REG number in the RB pair used as the second control channel region. FIG. 15 illustrates a case where an E-REG number is associated with each RB pair illustrated in FIGS. 13 and 14. Although the value of m-- ₁ is 0 in slot 0 and 10 in slot 1, it is not limited to this. For example, if m- ₁ in slot 0 is s, m-1 in slot ₁ is 4 * t + 2 + s. However, s and t are arbitrary natural numbers.

  The E-REG configuration shown in FIGS. 13 and 14 is an example, and the present invention is not limited to this. For example, the E-REG number is increased and cyclically shifted as the subcarrier number increases, but the E-REG number is decreased and cyclically shifted as the subcarrier number increases. It may be configured as follows. In other words, in the expression for obtaining the E-REG number of FIG. 15, k may be replaced with k ″, and an expression of k ″ = − 1 * (k−11) may be further added. Note that the present invention can be similarly applied to an E-REG configuration or an E-CCE configuration described below.

Note that, in the mathematical formulas shown in FIGS. 13 and 14, the case where the subcarrier number given for each RB pair is used has been described, but the present invention is not limited to this. For example, the subcarrier number may be given differently over the system bandwidth (component carrier). Specifically, this can be realized by further adding k = mod (k ″, N _sc ^RB ) to the mathematical formula for obtaining the E-REG number shown in FIG. Here, k ″ is a subcarrier number given differently over the system bandwidth. Note that the present invention can be similarly applied to an E-REG configuration or an E-CCE configuration described below.

Next, association with the E-CCE when the E-REG configuration shown in FIGS. 13 and 14 is used will be described. For both local and distributed mapping, the E-REG numbers associated with one E-CCE can be the same. For example, E- _REGs having the same remainder when an E-REG number is divided by _{NeCCE_L} ^RB can be associated with one E-CCE. However, in the case of local mapping, one E-CCE is associated with multiple E-REGs in one RB pair. For distributed mapping, one E-CCE is associated with multiple E-REGs in multiple RB pairs.

  For example, as shown in FIG. 13, when the number of E-REGs constituting one RB pair is 16, one E-CCE of local mapping is used in the RB pair used as the second control channel region. , Associated with E-REG0, E-REG4, E-REG8 and E-REG12 in the same RB pair. Also, for example, as shown in FIG. 13, when the number of E-REGs constituting one RB pair is 16, one E-CCE of distributed mapping is an RB used as the second control channel region. In the pair, it is associated with E-REG0, E-REG4, E-REG8 and E-REG12 in different RB pairs. For example, as shown in FIG. 14, when the number of E-REGs constituting one RB pair is 8, one E-CCE of local mapping is an RB used as the second control channel region. In the pair, it is associated with E-REG0 and E-REG4 in the same RB pair. Also, for example, as shown in FIG. 14, when the number of E-REGs constituting one RB pair is 8, one E-CCE of distributed mapping is an RB used as the second control channel region. Each pair is associated with E-REG0 and E-REG4 in different RB pairs.

In the E-REG configuration shown in FIGS. 13 and 14, the E-REG number in each RB pair used as the second control channel region is the same as the E-REG number shown in FIGS. Then, a remainder obtained by dividing a N _eREG ^RB by adding a multiple of a predetermined _{NeCCE_L} ^RB may be used. For example, E-REG numbers of the RB pair n _RB, to the E-REG numbers shown in FIGS. 13 and 14, by adding a material obtained by multiplying the n _RB and N _{ECCE_L} ^RB, the N _eREG ^RB You may use the remainder when dividing.

FIG. 16 is an example of an E-CCE configuration in local mapping. The E-CCEs in the local mapping are related as shown in FIG. The E-CCE in the local mapping is associated based on a plurality of E- _REGs having the same remainder when the E-REG number is divided by _{NeCCE_L} ^RB . For example, when N _eREG ^RB is 16 as shown in FIG. 9, E-CCE0 ( _{neCCE_L} = 0) in local mapping is four E-REGs (E-REG0 in RB1, E-REG4 in RB1, E-REG8 in RB1 and E-REG12 in RB1). For example, when N _eREG ^RB is 8 as shown in FIG. 10, E-CCE0 ( _{neCCE_L} = 0) in local mapping is two E-REGs (E-REG0 in RB1 and E-REG4 in RB1). Associated with By associating in this way, variations in the number of resource elements between E-CCEs described later can be suppressed.

  In addition, although the case where the E-CCE configuration in the local mapping is associated based on the E-REG has been described, the present invention is not limited to this, and the E-CCE configuration in the local mapping does not use the E-REG. Can be associated as a set of resource elements.

  FIG. 17 is a diagram illustrating an example of a mathematical expression for associating a resource element and E-CCE in local mapping. In FIG. 17, in the local mapping, a mathematical expression for associating an E-CCE number with respect to a resource element (k, l) of each RB pair and a resource element (k, l) with respect to the E-CCE number in each RB pair A formula for associating is shown. The formula for associating resource elements (k, l) for E-CCE numbers in each RB pair gives a set of resource elements associated with any E-CCE number.

  In addition, the E-REG configurations shown in FIGS. 9, 10, 13 and 14 can be arbitrarily exchanged in units of a predetermined set of resource elements in each RB pair. For example, in each RB pair, a predetermined subcarrier can be arbitrarily replaced as a unit. For example, in each RB pair, it is possible to arbitrarily replace each resource element set composed of three subcarriers from the lowest frequency as a unit. Specifically, in each RB pair, a set of resource elements composed of subcarrier numbers 0 to 2, a set of resource elements composed of subcarrier numbers 3 to 5, and subcarrier numbers 6 to 8 The set of configured resource elements and the set of resource elements configured with subcarrier numbers 9 to 11 can be arbitrarily switched. In addition, the arbitrary exchange may be performed in the same manner in all of the RB pairs used as the second control channel.

Further, the E-REG configuration shown in FIGS. 9, 10, 13, and 14 can use a plurality of patterns. The E-REG configuration in which a plurality of patterns are used can be switched based on predetermined parameters and configurations. For example, an E-REG configuration using a plurality of patterns can be used differently for each transmission point (base station, cell). For example, a plurality of patterns in the E-REG configuration can be switched based on n _shift and / or n _any shown in FIGS. 11, 12, and 15. In addition, for example, the plurality of patterns in the E-REG configuration can be switched based on the replacement pattern for arbitrarily replacing a predetermined set of resource elements in each RB pair already described. In addition, parameters for switching (determining, selecting, and setting) an E-REG configuration pattern such as n _shift , n _any , replacement pattern, and the like are transmitted from the base station to the terminal using RRC signaling or PDCCH signaling. You can be notified explicitly through. Also, parameters for switching (determining, selecting, setting) the pattern of the E-REG configuration such as n _shift , n _any , replacement pattern, etc. are implicitly determined based on other parameters and configurations. Can. As described above, since the E-REG configuration having a plurality of patterns is used, white noise is generated between the E-REGs having different patterns, thereby improving the transmission characteristics of the E-PDCCH.

  Next, effects of the E-REG configuration and / or E-CCE configuration described above will be described. In the E-REG configuration obtained by the mathematical expressions shown in FIG. 11, FIG. 12, and FIG. 15, the resource element of the RB pair used as the second control channel region is the first control channel described in FIG. Reference signals, transmission path condition measurement reference signals, terminal-specific reference signals, broadcast channels, synchronization signals, and the like may be mapped (multiplexed). In particular, when the terminal-specific reference signal is used to demodulate the second control channel, part or all of the terminal-specific reference signals of the antenna ports 107 to 110 are transmitted to the RB pair to which the second control channel is mapped. , Mapping (multiplexing). Note that the resource elements of the RB pair used as the second control channel region do not have to be mapped to the first control channel, the cell-specific reference signal, the transmission path condition measurement reference signal, the broadcast channel, and the synchronization signal. In addition, when the terminal-specific reference signals of CDM group 1 and CDM group 2 are used as shown in FIG. 4 in one RB pair to which the second control channel is mapped, resources that can map the second control channel The number of elements is 144 except for the resource elements to which the terminal-specific reference signal is mapped.

  In the E-REG configuration shown in FIGS. 9 and 13, when only the terminal-specific reference signals of CDM group 1 and CDM group 2 are mapped, the number of resource elements associated with each E-REG is about 9. . In the E-REG configuration shown in FIGS. 10 and 14, when only the terminal-specific reference signals of CDM group 1 and CDM group 2 are mapped, the number of resource elements associated with each E-REG is about 18 It is. Further, in the E-CCE configuration obtained based on the E-REG configuration shown in FIG. 9, FIG. 10, FIG. 13 and FIG. 14, when only the terminal-specific reference signals of CDM group 1 and CDM group 2 are mapped, The total number of resource elements associated with each E-CCE is 36. Here, the number of resource elements associated with the CCE used for the first control channel is 36. The number of resource elements associated with the E-CCE used for the second control channel is the same as the number of resource elements associated with the CCE used for the first control channel. For this reason, the transmission method, reception method, signal processing, and the like of the second control channel can be the same as those of the first control channel.

  In addition, when the first control channel and / or the cell-specific reference signal is mapped in the RB pair to which the second control channel is mapped, the number of resource elements to which the second control channel can be mapped decreases. Here, the variation in the number of resource elements between E-CCEs obtained based on the E-REG configuration of the present invention when the number of resource elements to which the second control channel can be mapped will be described. First, when the number of antenna ports of the cell-specific reference signal is 1 (antenna port 0), the maximum value of the number of resource elements between E-CCEs regardless of the number of first control channels (0 to 3) The difference from the minimum value is 1. In addition, when the number of antenna ports of the cell-specific reference signal is 2 (antenna ports 0 and 1), the maximum number of resource elements between E-CCEs regardless of the number of first control channels (0 to 3). The difference between the value and the minimum value is 0, and there is no variation in the number of resource elements between E-CCEs. Further, when the number of antenna ports of the cell-specific reference signal is 4 (antenna ports 0 to 3), the maximum number of resource elements between E-CCEs regardless of the number of first control channels (0 to 3). The difference between the value and the minimum value is 0, and there is no variation in the number of resource elements between E-CCEs. That is, by using the E-REG configuration of the present invention, variation in the number of resource elements between E-CCEs obtained based on the E-REG configuration is suppressed. Therefore, the size of the resource is hardly changed by E-CCE used for transmission of the second control channel. That is, the difference in transmission characteristics due to the coding gain for the second control channel is small depending on the E-CCE used for transmission of the second control channel. Thereby, the load of the scheduling process when the base station transmits the second control channel to the terminal can be significantly reduced.

  In addition, when the number of antenna ports of the cell-specific reference signal is 1 (antenna port 0), the RB pair to which the second control channel is mapped has 2 antenna ports of the cell-specific reference signal (antenna ports 0 and 1). ). That is, when the number of antenna ports of the cell-specific reference signal transmitted by the base station is 1 (antenna port 0), the base station transmits the second control channel to the terminal. Assuming that the number of antenna ports is 2 (antenna ports 0 and 1), the second control channel is mapped. When the number of antenna ports of the cell-specific reference signal transmitted by the base station is 1 (antenna port 0), the terminal detects the second control channel transmitted from the base station, Assuming that the number of antenna ports is 2 (antenna ports 0 and 1), the second control channel is demapped.

  In the above description, a case has been described in which the E-REG number associated with the RB pair is cyclically shifted in units of subcarriers in the frequency direction. The same can be explained from the viewpoint of the time direction. That is, the configuration (order, sequence, arrangement) of E-REGs in an arbitrary subcarrier may be cyclically shifted (cyclic shift) in units of OFDM symbols in the time direction between RBs or slots. Absent. For example, in each RB or slot, the configuration of E-REG on any subcarrier may be cyclically shifted with respect to the OFDM symbol. Further, as the subcarrier number increases, the E-REG configuration may be cyclically shifted by an arbitrary number of shifts. That is, an arbitrary E-REG number may be cyclically shifted by an arbitrary shift number as the subcarrier number increases. Also, any natural number can be used as the shift number for this subcarrier.

  Below, the detail of E-PDCCH is demonstrated. The control channel (E-PDCCH) mapped to the second control channel region is processed for each control information for one or a plurality of terminals, and, similar to the data channel, scramble processing, modulation processing, layer mapping processing, Recording processing and the like are performed. Also, precoding processing is performed on the control channel mapped to the second control channel region together with the terminal-specific reference signal.

  Hereinafter, SS (Search Space), which is an area for searching (searching, blind decoding) for the second control channel in terminal 200, will be described. The terminal 200 has the second control channel region set by the base station 100 and recognizes a plurality of E-CCEs in the second control channel region. In addition, the SS is set by the base station 100 for the terminal 200. For example, the terminal 200 is set with an E-CCE number recognized as SS by the base station 100. For example, the terminal 200 is set with one E-CCE number to be a start E-CCE number (reference E-CCE number) for the base station 100 to recognize as SS. The terminal 200 recognizes the SS unique to the terminal 200 based on the start E-CCE number and a predetermined rule. Here, the start E-CCE number is set by control information that is uniquely notified from base station 100 to terminal 200. In addition, the start E-CCE number may be determined based on an RNTI that is uniquely set from the base station 100 to the terminal 200. In addition, the start E-CCE number may be determined based on control information that is uniquely notified from base station 100 to terminal 200 and RNTI that is uniquely set from base station 100 to terminal 200. Further, the start E-CCE number may be determined based on a subframe number numbered for each subframe or a slot number numbered for each slot. As a result, the start E-CCE number is unique to terminal 200 and becomes unique information for each subframe or slot. Therefore, the SS of terminal 200 can be set differently for each subframe or slot. Various rules can be used for the rule for recognizing the SS from the start E-CCE number.

  The SS for searching for the second control channel in the terminal 200 can be configured from one or more E-CCEs. That is, it is configured by a set of one or more E-CCEs (E-CCE Aggregation) with the E-CCE in the region set as the second control channel region as a unit. The number of E-CCEs constituting this set is referred to as an “E-CCE aggregation level” (E-CCE aggregation level). The smallest E-CCE is composed of a plurality of E-CCEs having consecutive numbers, and the number of one or more E-CCEs having consecutive numbers is predetermined. Each SS of each E-CCE aggregation level is configured by an aggregation of a plurality of second control channel candidates. Further, the number of candidates for the second control channel may be defined for each E-CCE aggregation level. SS may be set for each E-CCE aggregation level. For example, the start E-CCE for setting the SS may be set for each E-CCE aggregation level.

  Base station 100 transmits the second control channel using one or more E-CCEs within the E-CCE set in terminal 200. Terminal 200 decodes the received signal using one or more E-CCEs in the SS, and performs a process for detecting the second control channel addressed to itself (blind decoding). The terminal 200 sets a different SS for each E-CCE aggregation level. Thereafter, terminal 200 performs blind decoding using a predetermined combination of E-CCEs in different SSs for each E-CCE aggregation level. In other words, terminal 200 performs blind decoding on each second control channel candidate in a different SS for each E-CCE aggregation level (monitors E-PDCCH).

  An example of SS for searching for the second control channel in terminal 200 will be described. The number of E-CCEs in the second control channel region is 16. The start E-CCE number is E-CCE12. The SS shifts from the start E-CCE number in the direction in which the E-CCE number increases. In SS, when the E-CCE number becomes the largest E-CCE number among the E-CCEs in the second control channel region, the E-CCE number to be shifted next is the E-CCE number in the second control channel region. -The smallest E-CCE number among the CCEs. That is, when the number of E-CCEs in the second control channel region is N and the start E-CCE number is X, the E-CCE number shifted to the m-th is mod (X + m, N). Here, mod (A, B) indicates a remainder obtained by dividing A by B. That is, SS is cyclically set within E-CCE in the second control channel region. For example, in the case of E-CCE aggregation level 4, the number of E-PDCCH candidates is two. The first E-PDCCH candidate is configured by E-CCE12, E-CCE13, E-CCE14, and E-CCE15. The second candidate for E-PDCCH is configured by E-CCE16, E-CCE1, E-CCE2, and E-CCE3. Accordingly, as described with reference to FIGS. 5 to 8, the second control channel region is set in units of predetermined RBs, whereby the E-PDCCH can be mapped in the predetermined RBs. That is, resources for mapping E-PDCCH can be set efficiently.

  Also, another example of SS for searching for the second control channel in terminal 200 will be described. Differences from the SS example already described are as follows. An E-CCE configured by one E-PDCCH is cyclically set within a predetermined E-CCE smaller than the E-CCE in the second control channel region. For example, among 16 E-CCEs, a resource for each of the four E-CCEs from the smallest E-CCE number is set as a unit for mapping one E-PDCCH. For example, in the case of E-CCE aggregation level 2, the number of E-PDCCH candidates is six. In addition, each E-PDCCH candidate is set (defined) so as to be mapped to as many units as possible in a unit for mapping one E-PDCCH. For example, the first E-PDCCH candidate is configured by E-CCE 12 and E-CCE 9. The second E-PDCCH candidate is configured by E-CCE16 and E-CCE13. The third E-PDCCH candidate is configured by E-CCE4 and E-CCE1. The fourth E-PDCCH candidate is configured by E-CCE8 and E-CCE5. The fifth E-PDCCH candidate is configured by E-CCE10 and E-CCE11. The sixth E-PDCCH candidate is configured by E-CCE14 and E-CCE15. Accordingly, as described with reference to FIGS. 5 to 8, the second control channel region is set in units of predetermined RBs, whereby the E-PDCCH can be mapped in the predetermined RBs. That is, resources for mapping E-PDCCH can be set efficiently. Further, in local mapping, when one RB is configured with a predetermined E-CCE, one E-PDCCH can be mapped to only one RB. Note that the E-PDCCH in the case of E-CCE aggregation level 8 is mapped to two RBs. Therefore, when the terminal-specific precoding process is performed on the E-PDCCH, a gain by the precoding process can be efficiently obtained. Also, terminal 200 can recognize a candidate for detecting such mapped E-PDCCH.

  In the above description, the entire E-CCE obtained from the RB pair set as the second control channel region is set as the SS setting range, but the present invention is not limited to this. For example, the E-CCE obtained from a part of the RB pair set as the second control channel region may be a range for setting the SS. That is, the RB pair or E-CCE set as the second control channel region may be different from the RB pair or E-CCE set as the SS. Even in such a case, it is preferable that the RB pair set as SS has a unit of a predetermined multiple. For example, when the number of RB pairs set as the second control channel region is 16, and the RB numbers in the second control channel region are RB1 to RB16, the E-CCE set as SS is RB5 It can be E-CCE obtained from RB8 and RB13 to RB16. Further, the resource set as SS may be an E-CCE in units of multiples of a predetermined number. When the E-CCE obtained from a part of the PRB set as the second control channel region is a range for setting the SS, the base station 100 sets the RB pair to be set as the second control channel region to the terminal 200. The information indicating and the information indicating the range to be set as SS from among them are notified through RRC signaling.

  In addition, although the case where the E-CCE aggregation levels are 1, 2, 4, and 8 has been described, the present invention is not limited to this. Other E-CCE aggregation levels may be used to change the predetermined reception quality of E-PDCCH or the overhead due to E-PDCCH.

  Hereinafter, the association between E-PDCCH (E-CCE, E-REG) and the antenna port of the terminal-specific reference signal will be described. A rule defined in advance is used for associating the E-PDCCH with the antenna port of the terminal-specific reference signal. Further, a plurality of association rules can be defined. When a plurality of associations between the E-PDCCH and the antenna port of the terminal-specific reference signal are defined, information indicating either one is explicitly or implicitly notified from the plurality of association rules. The notification method can be set by notifying information indicating any one of the plurality of association rules by RRC signaling. Further, when another notification method is associated with the control information included in the control information regarding the second control channel notified from the base station 100, the terminal 200 can identify one of the plurality of association rules. For example, one of a plurality of association rules may be notified indirectly from information indicating distributed mapping or local mapping notified by RRC signaling. Information indicating any one of a plurality of association rules may be set for each terminal. Information indicating any one of a plurality of association rules may be set for each second control channel region to be set. Therefore, when a plurality of second control channel regions are set, terminal 200 may set any one of a plurality of association rules independently.

  An example of a rule for associating an E-PDCCH with an antenna port of a terminal-specific reference signal is a terminal-specific precoding antenna port rule. In the terminal-specific precoding antenna port rule, precoding processing specific to the terminal transmitting the E-PDCCH can be performed. One RB is divided into a predetermined number of resources. The divided resources are associated with different antenna ports of terminal-specific reference signals. For example, one RB is divided into four resources. The four divided resources are associated with antenna ports 107 to 110, respectively. Each divided resource (divided resource) can be associated with E-CCE in local mapping. That is, each E-CCE in the local mapping is associated with a different antenna port. Further, when the E-CCE aggregation level is 2 or more, each E-PDCCH can be transmitted using any of the antenna ports associated with the divided resources to be mapped. Terminal 200 determines an antenna port of a terminal-specific reference signal for demodulation processing according to resources in E-PDCCH candidates for blind decoding. Also, terminal 200 may be notified from base station 100 of an antenna port of a terminal-specific reference signal for an E-PDCCH candidate for blind decoding. The terminal-specific precoding antenna port rule is preferably used when performing local mapping. The terminal-specific precoding antenna port rule may be used when distributed mapping is performed.

  Another example of the rule for associating the E-PDCCH with the antenna port of the terminal-specific reference signal is a shared antenna port rule. In the shared antenna port rule, a plurality of E-PDCCHs share an antenna port of a predetermined terminal-specific reference signal. In the shared antenna port rule, each terminal performs E-PDCCH demodulation processing using an antenna port of a predetermined terminal-specific reference signal. The terminal-specific reference signal of the antenna port is transmitted between a plurality of terminals. Shared by. In the second control channel region where the shared antenna port rule is used, part or all of the terminal-specific reference signals of the antenna ports 107 to 110 are used for E-PDCCH demodulation processing. Specifically, in the E-PDCCH mapped to the second control channel region where the shared antenna port rule is used, each of the E-REG or E-CCE to which the E-PDCCH is mapped is the antenna port 107 to 110. That is, in the second control channel region where the shared antenna port rule is used, the antenna port of the terminal-specific reference signal used in E-REG or E-CCE is selected based on the E-REG number or E-CCE number. (Decision) may be made. Also, the antenna port of the terminal-specific reference signal used in E-REG or E-CCE may be selected based on RNTI. The shared antenna port rule is preferably used when performing distributed mapping. The shared antenna port rule may be used when performing local mapping.

  In the above description, the mapping method between the RB and the E-CCE configuring the second control channel region has been described by the distributed mapping and the local mapping. However, the present invention is not limited to this. For example, the mapping method between the RB and the E-CCE constituting the second control channel region may be defined by a rule for associating the E-PDCCH with the antenna port of the terminal-specific reference signal. A mapping method between RBs and E-CCEs constituting the second control channel region may be defined by terminal-specific precoding antenna port rules and shared antenna port rules. For example, the distributed mapping in the above description may be a mapping when a shared antenna port rule is used. Further, the local mapping in the above description may be a mapping when the terminal-specific precoding antenna port rule is used.

  In the following, a second control channel setting method (second control channel region setting method / second control channel monitoring setting method) for base station 100 to terminal 200 will be described. As an example, the setting of the second control channel region and the setting of the transmission mode implicitly indicate the setting of monitoring of the second control channel. The base station 100 sets the second control channel by notifying the terminal 200 of terminal-specific setting information (RadioResourceConfigDedicated) for the radio resource through higher layer control information (RRC signaling). The terminal-specific setting information for radio resources is control information used for setting / changing / releasing resource blocks, terminal-specific settings for physical channels, and the like.

  Base station 100 notifies terminal 200 of terminal-specific setting information for radio resources. Terminal 200 performs terminal-specific settings for radio resources based on terminal-specific setting information for radio resources from base station 100, and notifies base station 100 of the completion of setting of terminal-specific setting information for radio resources.

  The terminal-specific setting information for the radio resource is configured to include terminal-specific setting information (PhysicalConfigDedicated) for the physical channel. The terminal-specific setting information for the physical channel is control information that defines terminal-specific settings for the physical channel. The terminal-specific setting information for the physical channel includes transmission path status report setting information (CQI-ReportConfig), terminal information for antenna information (AntennaInfoDedicated), and terminal-specific setting information for the second control channel (EPDCCH-ConfigDedicated). Consists of. The setting information of the transmission path status report is used to define setting information for reporting the transmission path status in the downlink. The terminal-specific setting information of the antenna information is used to define terminal-specific antenna information in the base station 100. The terminal-specific setting information for the second control channel is used to define terminal-specific setting information for the second control channel. In addition, since the terminal-specific setting information of the second control channel is notified and set as control information specific to terminal 200, the second control channel area to be set is set as an area specific to terminal 200. The

  The setting information of the transmission path status report is configured to include setting information (cqi-ReportModeAperiodic) of the aperiodic transmission path status report and setting information (CQI-ReportPeriodic) of the periodic transmission path status report. The setting information for the aperiodic transmission path status report is setting information for aperiodically reporting the transmission path status in the downlink 103 through an uplink shared channel (PUSCH). The setting information of the periodic transmission path status report is setting information for periodically reporting the transmission path status in the downlink through an uplink control channel (PUCCH).

  The terminal-specific setting information of the antenna information includes a transmission mode (transmission Mode). The transmission mode is information indicating a transmission method in which the base station 100 communicates with the terminal 200. For example, the transmission mode is defined in advance as transmission modes 1 to 10. Transmission mode 1 is a transmission mode using a single antenna port transmission method using antenna port 0. Transmission mode 2 is a transmission mode using a transmission diversity method. Transmission mode 3 is a transmission mode that uses a cyclic delay diversity scheme. Transmission mode 4 is a transmission mode that uses a closed-loop spatial multiplexing scheme. Transmission mode 5 is a transmission mode that uses a multi-user MIMO scheme. Transmission mode 6 is a transmission mode that uses a closed-loop spatial multiplexing scheme that uses a single antenna port. The transmission mode 7 is a transmission mode using a single antenna port transmission method using the antenna port 5. Transmission mode 8 is a transmission mode that uses a closed-loop spatial multiplexing scheme that uses antenna ports 7 to 8. Transmission mode 9 is a transmission mode that uses a closed-loop spatial multiplexing scheme that uses antenna ports 7 to 14. Transmission modes 1 to 9 are also referred to as a first transmission mode.

  The transmission mode 10 is defined as a transmission mode different from the transmission modes 1 to 9. For example, the transmission mode 10 can be a transmission mode using a CoMP scheme. Here, the expansion due to the introduction of the CoMP method includes optimization of the transmission path status report and improvement of accuracy (for example, introduction of precoding information suitable for CoMP communication, phase difference information between base stations, etc.) and the like. Also, the transmission mode 10 can be a transmission mode that uses a communication method that is an extension (sophistication) of the multi-user MIMO method that can be realized by the communication methods shown in the transmission modes 1 to 9. Here, the extension of the multi-user MIMO scheme is optimized for transmission path condition reports and accuracy improvement (for example, introduction of CQI (Channel Quality Indicator) information suitable for multi-user MIMO communication) and multiplexed on the same resource. Including improvement of orthogonality between terminals. The transmission mode 10 can be a transmission mode in which the second control channel region can be set. Further, the transmission mode 10 can be a transmission mode using a CoMP scheme and / or an extended multi-user MIMO scheme in addition to all or part of the communication schemes shown in the transmission modes 1 to 9. For example, the transmission mode 10 can be a transmission mode that uses a CoMP scheme and / or an extended multi-user MIMO scheme in addition to the communication scheme shown in the transmission mode 9. Also, the transmission mode 10 can be a transmission mode in which a plurality of reference signals (CSI-RS; Channel State Information-RS) for channel state measurement can be set. The transmission mode 10 is also called a second transmission mode.

  Note that the base station 100 does not notify the terminal set to the transmission mode 10 that can use a plurality of transmission schemes that one of the plurality of transmission schemes is used when transmitting the data channel. Can also communicate. That is, even if the terminal 200 is set to the transmission mode 10 that can use a plurality of transmission schemes, the terminal 200 can communicate without receiving any notification of using one of the plurality of transmission schemes when receiving a data channel. it can.

  Here, the second transmission mode is a transmission mode in which the second control channel can be set. That is, when the base station 100 is set to the first transmission mode for the terminal 200, the base station 100 maps the control channel for the terminal 200 to the first control channel region. Further, when the base station 100 is set to the second transmission mode for the terminal 200, the base station 100 maps the control channel for the terminal 200 to the first control channel region and / or the second control channel region. On the other hand, when the base station 100 sets the first transmission mode, the terminal 200 performs blind decoding on the first control channel. Furthermore, when the base station 100 sets the second transmission mode, the terminal 200 performs blind decoding on the first control channel and / or the second control channel.

  Also, terminal 200 sets a control channel for blind decoding based on whether terminal-specific setting information of the second control channel is set by base station 100 regardless of the transmission mode. That is, when the terminal-specific setting information of the second control channel is not set for terminal 200, base station 100 maps the control channel for terminal 200 to the first control channel region. Further, when the terminal-specific setting information of the second control channel is set for terminal 200, base station 100 sets the control channel for terminal 200 to the first control channel region and / or the second control channel region. Map. On the other hand, when the terminal-specific setting information of the second control channel is set by the base station 100, the terminal 200 performs blind decoding on the first control channel and / or the second control channel. In addition, when the terminal-specific setting information of the second control channel is not set by the base station 100, the terminal 200 performs blind decoding on the first control channel.

  The terminal-specific setting information of the second control channel includes subframe setting information (EPDCCH-SubframeConfig-r11) of the second control channel. The subframe setting information of the second control channel is used for defining subframe information for setting the second control channel. The subframe setting information of the second control channel is configured to include a subframe setting pattern (subframeConfigPattern-r11) and second control channel setting information (epdcch-Config-r11).

  The subframe setting pattern is information indicating a subframe for setting the second control channel. For example, the subframe setting pattern is n-bit bitmap format information. The information shown in each bit indicates whether or not the subframe is set as the second control channel. That is, the subframe setting pattern can set n subframes as a cycle. At that time, a predetermined subframe to which a synchronization signal, a broadcast channel, and the like are mapped can be excluded. Specifically, the remainder obtained by dividing the subframe number defined for each subframe by n corresponds to each bit of the subframe setting pattern. For example, n is defined in advance as a value such as 8 or 40. When the information for a subframe having a subframe setting pattern is “1”, the subframe is set as the second control channel. When information on a subframe having a subframe setting pattern is “0”, the subframe is not set as the second control channel. In addition, a predetermined subframe to which a synchronization signal for the terminal 200 to synchronize with the base station 100, a broadcast channel for broadcasting the control information of the base station 100, and the like is mapped is not set as a second control channel in advance. can do. In another example of the subframe setting pattern, the subframe pattern set as the second control channel is indexed in advance, and information indicating the index is defined as the subframe setting pattern.

  The terminal-specific setting information of the second control channel includes resource allocation information (resourceBlockAssignment-r11). The resource allocation information is information for designating a resource block to be set as the second control channel. For example, the second control channel region can be set in units of one RB pair.

  As described above, when setting the second control channel for the terminal 200, the base station 100 includes the terminal-specific setting information of the second control channel in the terminal-specific setting information for the radio resource by RRC signaling. To notify. Further, when the base station 100 changes the second control channel set for the terminal 200, the radio resource including the terminal-specific setting information of the second control channel whose parameter has been changed similarly by RRC signaling. Notify terminal-specific setting information for. Further, when releasing (releasing) the set second control channel, the base station 100 similarly notifies the terminal 200 by RRC signaling. For example, the terminal specific setting information for the radio resource not including the terminal specific setting information of the second control channel is notified. Also, control information for releasing the terminal-specific setting information of the second control channel may be notified.

  In each of the embodiments described above, resource elements and resource blocks are used as data channel, control channel, PDSCH, PDCCH and reference signal mapping units, and subframes and radio frames are used as time direction transmission units. This is not a limitation. The same effect can be obtained even if a region and a time unit composed of an arbitrary frequency and time are used instead.

  In each of the above embodiments, the extended physical downlink control channel 103 arranged in the PDSCH region is referred to as E-PDCCH, and the distinction from the conventional physical downlink control channel (PDCCH) has been clarified. However, it is not limited to this. Even if both are referred to as PDCCH, if the extended physical downlink control channel arranged in the PDSCH region and the conventional physical downlink control channel arranged in the PDCCH region perform different operations, the E-PDCCH And PDCCH are substantially the same as the embodiments described above.

  When the terminal starts communication with the base station, information (terminal capability information or function group information) indicating whether the functions described in the above embodiments can be used for the base station By notifying the station, the base station can determine whether or not the functions described in the above embodiments can be used. More specifically, when the function described in each of the above embodiments can be used, information indicating it is included in the terminal capability information, and when the function described in each of the above embodiments is not usable, Information related to this function may not be included in the terminal capability information. Alternatively, when the function described in each of the above embodiments can be used, 1 is set in the predetermined bit field of the function group information, and when the function described in each of the above embodiments is not usable, the function group information The predetermined bit field may be set to 0.

  In each of the embodiments described above, resource elements and resource blocks are used as data channel, control channel, PDSCH, PDCCH and reference signal mapping units, and subframes and radio frames are used as time direction transmission units. This is not a limitation. The same effect can be obtained even if a region and a time unit composed of an arbitrary frequency and time are used instead. In each of the above embodiments, the case of demodulating using a precoded RS is described, and the port corresponding to the precoded RS is described using a port equivalent to the MIMO layer. However, it is not limited to this. In addition, the same effect can be obtained by applying the present invention to ports corresponding to different reference signals. For example, Unprecoded RS is used instead of Precoded RS, and a port equivalent to an output end after precoding processing or a port equivalent to a physical antenna (or a combination of physical antennas) can be used as a port.

  The program that operates in the base station 100 and the terminal 200 related to the present invention is a program that controls a CPU or the like (a program that causes a computer to function) so as to realize the functions of the above-described embodiments related to the present invention. Information handled by these devices is temporarily stored in the RAM at the time of processing, then stored in various ROMs and HDDs, read out by the CPU, and corrected and written as necessary. As a recording medium for storing the program, a semiconductor medium (for example, ROM, nonvolatile memory card, etc.), an optical recording medium (for example, DVD, MO, MD, CD, BD, etc.), a magnetic recording medium (for example, magnetic tape, Any of a flexible disk etc. may be sufficient. In addition, by executing the loaded program, not only the functions of the above-described embodiment are realized, but also based on the instructions of the program, the processing is performed in cooperation with the operating system or other application programs. The functions of the invention may be realized.

  In the case of distribution in the market, the program can be stored and distributed in a portable recording medium, or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer is also included in the present invention. Further, part or all of the base station 100 and the terminal 200 in the above-described embodiment may be realized as an LSI that is typically an integrated circuit. Each functional block of base station 100 and terminal 200 may be individually chipped, or a part or all of them may be integrated into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention. The present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention. It is. Moreover, it is the element described in each said embodiment, and the structure which substituted the element which has the same effect is also contained.

  The present invention is suitable for use in a radio base station apparatus, a radio terminal apparatus, a radio communication system, and a radio communication method.

100 Base station 101, 206 Upper layer 102 Data channel generation unit 103 Second control channel generation unit 104 Terminal specific reference signal multiplexing unit 105 Precoding unit 106 First control channel generation unit 107 Cell specific reference signal multiplexing unit 108 Transmission signal Generation unit 109 Transmission unit 200, 1104 Terminal 201 Reception unit 202 Reception signal processing unit 203 Propagation path estimation unit 204 Control channel processing unit 205 Data channel processing unit 1801 Macro base stations 1802, 1803 RRH
1808, 1809 Lines 1805, 1806, 1807 Coverage

Claims (13)

A resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, and a first resource block and a second resource that are two resource blocks continuous in the time direction A base station that communicates with a terminal using a resource block pair composed of blocks,
A second control channel generation unit that generates a second control channel to be transmitted using a reference signal of an antenna port different from the first control channel;
The second control channel is transmitted to the terminal using one or more E-CCEs associated with a predetermined E-REG;
The E-REG is associated with a predetermined resource element in each of the first resource block and the second resource block,
The resource element associated with the E-REG in the OFDM symbol is cyclic in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction. Shift to the base station. When the second control channel is transmitted using local mapping, the E-CCE used for transmission of the second control channel is associated with a plurality of the E-REGs in one resource block pair. ,
When the second control channel is transmitted using distributed mapping, the E-CCE used for transmission of the second control channel is associated with the plurality of E-REGs in the plurality of resource block pairs. The base station according to claim 1.   The base station according to claim 1 or 2, wherein the predetermined number of the E-REGs associated with the first resource block is equal to the predetermined number of the E-REGs associated with the second resource block. A resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, and a first resource block and a second resource that are two resource blocks continuous in the time direction A terminal that communicates with a base station using a resource block pair composed of blocks,
A control channel processing unit that detects a second control channel using a reference signal of an antenna port different from the first control channel;
The second control channel is transmitted from the base station using one or more E-CCEs associated with a predetermined E-REG,
The E-REG is associated with a predetermined resource element in each of the first resource block and the second resource block,
The resource element associated with the E-REG in the OFDM symbol is cyclic in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction. Shift to the terminal. When the second control channel is transmitted using local mapping, the E-CCE used for transmission of the second control channel is associated with a plurality of the E-REGs in one resource block pair. ,
When the second control channel is transmitted using distributed mapping, the E-CCE used for transmission of the second control channel is associated with the plurality of E-REGs in the plurality of resource block pairs. The terminal according to claim 4.   The terminal according to claim 4 or 5, wherein the predetermined number of the E-REGs associated with the first resource block is equal to the predetermined number of the E-REGs associated with the second resource block. A resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, and a first resource block and a second resource that are two resource blocks continuous in the time direction A communication system in which a terminal and a base station communicate with each other using a resource block pair composed of blocks,
The base station
A second control channel generation unit that generates a second control channel to be transmitted using a reference signal of an antenna port different from the first control channel;
The terminal
A control channel processing unit for detecting the second control channel;
The second control channel is transmitted from the base station to the terminal using one or more E-CCEs associated with a predetermined E-REG,
The E-REG is associated with a predetermined resource element in each of the first resource block and the second resource block,
The resource element associated with the E-REG in the OFDM symbol is cyclic in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction. Shift to a communication system. When the second control channel is transmitted using local mapping, the E-CCE used for transmission of the second control channel is associated with a plurality of the E-REGs in one resource block pair. ,
When the second control channel is transmitted using distributed mapping, the E-CCE used for transmission of the second control channel is associated with the plurality of E-REGs in the plurality of resource block pairs. The communication system according to claim 7.   The communication system according to claim 7 or 8, wherein the predetermined number of the E-REGs associated with the first resource block is equal to the predetermined number of the E-REGs associated with the second resource block. A resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, and a first resource block and a second resource that are two resource blocks continuous in the time direction A communication method of a base station that communicates with a terminal using a resource block pair composed of blocks,
Generating a second control channel to be transmitted using a reference signal of an antenna port different from the first control channel;
The second control channel is transmitted to the terminal using one or more E-CCEs associated with a predetermined E-REG;
The E-REG is associated with a predetermined resource element in each of the first resource block and the second resource block,
The resource element associated with the E-REG in the OFDM symbol is cyclic in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction. Shift to the communication method. A resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, and a first resource block and a second resource that are two resource blocks continuous in the time direction A communication method of a terminal that communicates with a base station using a resource block pair composed of blocks,
Detecting a second control channel using a reference signal of an antenna port different from the first control channel;
The second control channel is transmitted from the base station using one or more E-CCEs associated with a predetermined E-REG,
The E-REG is associated with a predetermined resource element in each of the first resource block and the second resource block,
The resource element associated with the E-REG in the OFDM symbol is cyclic in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction. Shift to the communication method. A resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, and a first resource block and a second resource that are two resource blocks continuous in the time direction An integrated circuit of a base station that communicates with a terminal using a resource block pair composed of blocks,
Realizing a function of generating a second control channel transmitted using a reference signal of an antenna port different from the first control channel;
The second control channel is transmitted to the terminal using one or more E-CCEs associated with a predetermined E-REG;
The E-REG is associated with a predetermined resource element in each of the first resource block and the second resource block,
The resource element associated with the E-REG in the OFDM symbol is cyclic in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction. Integrated circuit to shift to. A resource element composed of an OFDM symbol and a subcarrier, a resource block composed of a predetermined number of the resource elements, and a first resource block and a second resource that are two resource blocks continuous in the time direction An integrated circuit of a terminal that communicates with a base station using a resource block pair composed of blocks,
A function for detecting the second control channel by using a reference signal of an antenna port different from the first control channel is realized.
The second control channel is transmitted from the base station using one or more E-CCEs associated with a predetermined E-REG,
The E-REG is associated with a predetermined resource element in each of the first resource block and the second resource block,
The resource element associated with the E-REG in the OFDM symbol is cyclic in the frequency direction using a predetermined number of shifts as the OFDM symbol advances in the time direction in a predetermined number of the resource blocks in the frequency direction. Integrated circuit to shift to.