WO2018030736A1 - Method for transmitting/receiving data in wireless communication system and apparatus supporting same - Google Patents

Abstract

The present invention relates to a method for transmitting data by a transmission apparatus in a wireless communication system and an apparatus therefor. The present invention may provide a method and an apparatus therefor, the method comprising: dividing a transport block into one or more code blocks; performing a channel coding on each of the one or more code blocks; concatenating the one or more code blocks, wherein the one or more code blocks are interleaved in a predetermined bit unit; scrambling the one or more concatenated code blocks; and modulating the one or more scrambled code blocks.

Description

Method for transmitting and receiving data in a wireless communication system and apparatus supporting the same

The present invention relates to a method for transmitting and receiving data by a transmitting device in a wireless communication system, and more particularly, to a method for generating and transmitting data through an interleaving method and an apparatus for supporting the same.

Mobile communication systems have been developed to provide voice services while ensuring user activity. However, the mobile communication system has expanded not only voice but also data service.As a result of the explosive increase in traffic, a shortage of resources and users are demanding higher speed services, a more advanced mobile communication system is required. have.

The requirements of the next generation of mobile communication systems are to support the massive explosive data traffic, the dramatic increase in the data rate per user, the large increase in the number of connected devices, the very low end-to-end latency, and the high energy efficiency. It should be possible. Dual Connectivity, Massive Multiple Input Multiple Output (MIMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), Super Wideband Various technologies such as wideband support and device networking have been studied.

An object of the present invention is to provide a method and apparatus for transmitting and receiving data.

Another object of the present invention is to provide a data transmission method and apparatus for compensating for an impairment caused by phase noise occurring during data transmission and reception.

Another object of the present invention is to provide a method and apparatus for transmitting data through interleaving in order to compensate for obstacles caused by phase noise.

Another object of the present invention is to provide a method and apparatus for transmitting a reference signal for demodulating data in order to compensate for a disturbance caused by phase noise.

Another object of the present invention is to provide an interleaving method and apparatus for improving the decoding speed of data.

The technical problems to be achieved in the present specification are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

The present invention provides a method and apparatus for transmitting data in a wireless communication system in order to solve the above problems.

Specifically, the random access method of the terminal according to an embodiment of the present invention, splitting the transport block into one or a plurality of code blocks; Performing channel coding on each of the one or multiple code blocks; Concatenating the one or more code blocks, interleaving the one or more code blocks by a specific bit unit; Scrambling the concatenated one or more code blocks; And modulating the scrambled one or multiple code blocks.

Further, in the present invention, the one or more code blocks are grouped into a certain number of groups and interleaved by groups.

The present invention may further include attaching a cyclic redundancy check (CRC) to each of the specific number of groups.

The present invention may further include interleaving the concatenated one or more code blocks in a specific bit unit.

Also, in the present invention, the interleaving may include: grouping the concatenated one or a plurality of code blocks into a specific number of groups; And interleaving the grouped one or more code blocks by group.

The present invention may further include interleaving the modulated one or more code blocks in a specific symbol unit.

Further, in the present invention, the interleaving may include: grouping the multiplexed one or more code blocks into a specific number of groups; And interleaving the grouped one or more code blocks by group.

The present invention may further include transmitting control information indicating whether the one or more code blocks are interleaved to a receiving device.

The present invention also provides a method comprising: transmitting control information indicating whether a reference signal for demodulating the data is transmitted according to whether one or more code blocks are interleaved; And if the control information indicates transmission of the reference signal, transmitting the reference signal to a receiving device.

In addition, the present invention comprises the steps of: mapping the multiplexed one or more code blocks to at least one layer; Precoding the one or more code blocks mapped to the at least one layer; And mapping the precoded one or more code blocks to a transmission resource using a time priority mapping technique or a frequency priority mapping technique.

In addition, the present invention, the communication unit for transmitting and receiving a wireless signal with the outside; And a processor operatively coupled to the communication unit, wherein the processor divides the transport block into one or a plurality of code blocks, performs channel coding on each of the one or a plurality of code blocks, and Concatenation of one or more code blocks, interleaving the one or more code blocks by a specific bit unit, scrambling the concatenated one or more code blocks, and scrambled Provided is a transmission apparatus for modulating one or multiple code blocks.

According to the present invention, interleaving is performed to generate data, thereby making it possible to compensate for impairment due to phase noise.

In addition, the present invention generates data by interleaving the entire code blocks during concatenation of segmented code blocks, so that the entire data is not damaged even if an error occurs in a specific symbol.

In addition, by interleaving the concatenated code blocks by bit unit or symbol unit, the present invention has an effect of compensating for impairment due to phase noise generated during data transmission and reception.

In addition, the present invention has the effect of improving the speed of data decoding by interleaving code blocks according to groups.

In addition, the present invention has an effect that can compensate for the impairment (phase pair) caused by the phase noise (phase noise) generated during data transmission and reception by transmitting a reference signal for data demodulation.

In addition, the present invention has the effect of efficiently compensating for the impairment (phase pair) caused by the phase noise (transmission noise) generated during data transmission and reception by producing data through interleaving, and transmitting a reference signal for demodulation of data. .

Effects obtained in the present specification are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, included as part of the detailed description in order to provide a thorough understanding of the present invention, provide embodiments of the present invention and together with the description, describe the technical features of the present invention.

1 illustrates a structure of a radio frame in a wireless communication system to which the present invention can be applied.

2 is a diagram illustrating a resource grid for one downlink slot in a wireless communication system to which the present invention can be applied.

3 shows a structure of a downlink subframe in a wireless communication system to which the present invention can be applied.

4 shows a structure of an uplink subframe in a wireless communication system to which the present invention can be applied.

5 shows an example of a signal processing procedure of an uplink shared channel which is a transport channel in a wireless communication system to which the present invention can be applied.

FIG. 6 shows an example of a signal processing procedure of a downlink shared channel which is a transport channel in a wireless communication system to which the present invention can be applied.

7 shows an example of a resource element mapping method to which the present invention can be applied.

8 illustrates a reference signal pattern mapped to a downlink resource block pair in a wireless communication system to which the present invention can be applied.

9 shows an example of a power spectral density of an oscillator.

10 and 11 illustrate an example of an interleaving method in a concatenation step to which the invention can be applied.

12 and 13 illustrate another example of an interleaving method in a concatenation step to which the present invention can be applied.

14 shows an example of a method of adding a CRC to a code block to which the present invention can be applied.

15 and 16 illustrate an example of an interleaving method of concatenated code blocks to which the present invention can be applied.

17 and 18 show an example of an interleaving method of modulated code blocks to which the present invention can be applied.

19 illustrates an example of a reference signal defined for each layer to which the present invention can be applied.

20 is a flowchart illustrating an example of a method for transmitting data by a transmitting apparatus to which the present invention can be applied.

21 illustrates a block diagram of a wireless communication device to which the present invention can be applied.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention.

In this specification, a base station has a meaning as a terminal node of a network that directly communicates with a terminal. The specific operation described as performed by the base station in this document may be performed by an upper node of the base station in some cases. That is, it is obvious that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A 'base station (BS)' may be replaced by terms such as a fixed station, a Node B, an evolved-NodeB (eNB), a base transceiver system (BTS), an access point (AP), and the like. . In addition, a 'terminal' may be fixed or mobile, and may include a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), and an AMS ( Advanced Mobile Station (WT), Wireless Terminal (WT), Machine-Type Communication (MTC) Device, Machine-to-Machine (M2M) Device, Device-to-Device (D2D) Device, etc.

Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal and a receiver may be part of a base station.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention.

The following techniques are code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and NOMA It can be used in various radio access systems such as non-orthogonal multiple access. CDMA may be implemented by a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA). UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA, and employs OFDMA in downlink and SC-FDMA in uplink. LTE-A (advanced) is the evolution of 3GPP LTE.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document.

For clarity, the following description focuses on 3GPP LTE / LTE-A, but the technical features of the present invention are not limited thereto.

General wireless communication system to which the present invention can be applied

1 illustrates a structure of a radio frame in a wireless communication system to which the present invention can be applied.

3GPP LTE / LTE-A supports a type 1 radio frame structure applicable to frequency division duplex (FDD) and a type 2 radio frame structure applicable to time division duplex (TDD).

In FIG. 1, the size of the radio frame in the time domain is expressed as a multiple of a time unit of T_s = 1 / (15000 * 2048). Downlink and uplink transmission consists of a radio frame having a period of T_f = 307200 * T_s = 10ms.

1A illustrates the structure of a type 1 radio frame. Type 1 radio frames may be applied to both full duplex and half duplex FDD.

A radio frame consists of 10 subframes. One radio frame is composed of 20 slots having a length of T_slot = 15360 * T_s = 0.5ms, and each slot is assigned an index of 0 to 19. One subframe consists of two consecutive slots in the time domain, and subframe i consists of slot 2i and slot 2i + 1. The time taken to transmit one subframe is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms and one slot may have a length of 0.5 ms.

In FDD, uplink transmission and downlink transmission are distinguished in the frequency domain. While there is no restriction on full-duplex FDD, the terminal cannot simultaneously transmit and receive in half-duplex FDD operation.

One slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. Since 3GPP LTE uses OFDMA in downlink, the OFDM symbol is for representing one symbol period. The OFDM symbol may be referred to as one SC-FDMA symbol or symbol period. A resource block is a resource allocation unit and includes a plurality of consecutive subcarriers in one slot.

FIG. 1B illustrates a frame structure type 2. FIG.

Type 2 radio frames consist of two half frames each 153600 * T_s = 5 ms in length. Each half frame consists of five subframes of 30720 * T_s = 1ms in length.

In a type 2 frame structure of a TDD system, an uplink-downlink configuration is a rule indicating whether uplink and downlink are allocated (or reserved) for all subframes.

Table 1 shows an uplink-downlink configuration.

Referring to Table 1, for each subframe of a radio frame, 'D' represents a subframe for downlink transmission, 'U' represents a subframe for uplink transmission, and 'S' represents a downlink pilot. A special subframe consisting of three fields: a time slot, a guard period (GP), and an uplink pilot time slot (UpPTS).

DwPTS is used for initial cell search, synchronization or channel estimation at the terminal. UpPTS is used for channel estimation at the base station and synchronization of uplink transmission of the terminal. GP is a section for removing interference caused in the uplink due to the multipath delay of the downlink signal between the uplink and the downlink.

Each subframe i is composed of slots 2i and slots 2i + 1 each having a length of T_slot = 15360 * T_s = 0.5ms.

The uplink-downlink configuration can be classified into seven types, and the location and / or number of downlink subframes, special subframes, and uplink subframes are different for each configuration.

The time point when the downlink is changed from the uplink or the time point when the uplink is switched to the downlink is called a switching point. Switch-point periodicity refers to a period in which an uplink subframe and a downlink subframe are repeatedly switched in the same manner, and both 5ms or 10ms are supported. In case of having a period of 5ms downlink-uplink switching time, the special subframe S exists every half-frame, and in case of having a period of 5ms downlink-uplink switching time, it exists only in the first half-frame.

In all configurations, subframes 0 and 5 and DwPTS are sections for downlink transmission only. The subframe immediately following the UpPTS and the subframe subframe is always an interval for uplink transmission.

The uplink-downlink configuration may be known to both the base station and the terminal as system information. When the uplink-downlink configuration information is changed, the base station may notify the terminal of the change of the uplink-downlink allocation state of the radio frame by transmitting only an index of the configuration information. In addition, the configuration information is a kind of downlink control information, which may be transmitted through a physical downlink control channel (PDCCH) like other scheduling information, and is commonly transmitted to all terminals in a cell through a broadcast channel as broadcast information. May be

Table 2 shows the configuration of the special subframe (length of DwPTS / GP / UpPTS).

The structure of a radio frame according to the example of FIG. 1 is just one example, and the number of subcarriers included in the radio frame or the number of slots included in the subframe and the number of OFDM symbols included in the slot may vary. Can be.

2 is a diagram illustrating a resource grid for one downlink slot in a wireless communication system to which the present invention can be applied.

Referring to FIG. 2, one downlink slot includes a plurality of OFDM symbols in the time domain. Here, one downlink slot includes seven OFDM symbols, and one resource block includes 12 subcarriers in a frequency domain, but is not limited thereto.

Each element on the resource grid is a resource element, and one resource block (RB) includes 12 × 7 resource elements. The number N ^ DL of resource blocks included in the downlink slot depends on the downlink transmission bandwidth.

The structure of the uplink slot may be the same as the structure of the downlink slot.

3 shows a structure of a downlink subframe in a wireless communication system to which the present invention can be applied.

Referring to FIG. 3, up to three OFDM symbols in the first slot in a subframe are control regions to which control channels are allocated, and the remaining OFDM symbols are data regions to which PDSCH (Physical Downlink Shared Channel) is allocated. data region). An example of a downlink control channel used in 3GPP LTE includes a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), a physical hybrid-ARQ indicator channel (PHICH), and the like.

The PCFICH is transmitted in the first OFDM symbol of a subframe and carries information about the number of OFDM symbols (ie, the size of the control region) used for transmission of control channels within the subframe. The PHICH is a response channel for the uplink and carries an ACK (Acknowledgement) / NACK (Not-Acknowledgement) signal for a hybrid automatic repeat request (HARQ). Control information transmitted through the PDCCH is called downlink control information (DCI). The downlink control information includes uplink resource allocation information, downlink resource allocation information or an uplink transmission (Tx) power control command for a certain terminal group.

The PDCCH is a resource allocation and transmission format of DL-SCH (Downlink Shared Channel) (also referred to as a downlink grant), resource allocation information of UL-SCH (Uplink Shared Channel) (also called an uplink grant), and PCH ( Paging information in paging channel, system information in DL-SCH, resource allocation for upper-layer control message such as random access response transmitted in PDSCH, arbitrary terminal It may carry a set of transmission power control commands for the individual terminals in the group, activation of Voice over IP (VoIP), and the like. The plurality of PDCCHs may be transmitted in the control region, and the terminal may monitor the plurality of PDCCHs. The PDCCH consists of a set of one or a plurality of consecutive CCEs. CCE is a logical allocation unit used to provide a PDCCH with a coding rate according to the state of a radio channel. The CCE corresponds to a plurality of resource element groups. The format of the PDCCH and the number of available PDCCH bits are determined according to the correlation between the number of CCEs and the coding rate provided by the CCEs.

The base station determines the PDCCH format according to the DCI to be transmitted to the terminal, and attaches a CRC (Cyclic Redundancy Check) to the control information. The CRC is masked with a unique identifier (referred to as RNTI (Radio Network Temporary Identifier)) according to the owner or purpose of the PDCCH. If the PDCCH for a specific terminal, a unique identifier of the terminal, for example, a C-RNTI (Cell-RNTI) may be masked to the CRC. Alternatively, if the PDCCH is for a paging message, a paging indication identifier, for example, P-RNTI (P-RNTI) may be masked to the CRC. If the system information, more specifically, the PDCCH for the system information block (SIB), the system information identifier and the system information RNTI (SI-RNTI) may be masked to the CRC. In order to indicate a random access response that is a response to the transmission of the random access preamble of the UE, a random access-RNTI (RA-RNTI) may be masked to the CRC.

4 shows a structure of an uplink subframe in a wireless communication system to which the present invention can be applied.

Referring to FIG. 4, an uplink subframe may be divided into a control region and a data region in the frequency domain. A physical uplink control channel (PUCCH) carrying uplink control information is allocated to the control region. The data region is allocated a Physical Uplink Shared Channel (PUSCH) that carries user data. In order to maintain a single carrier characteristic, one UE does not simultaneously transmit a PUCCH and a PUSCH.

A PUCCH for one UE is allocated a resource block (RB) pair in a subframe. RBs belonging to the RB pair occupy different subcarriers in each of the two slots. This RB pair allocated to the PUCCH is said to be frequency hopping at the slot boundary (slot boundary).

5 illustrates an example of a signal processing procedure of an uplink shared channel which is a transport channel in a wireless communication system to which the present invention can be applied.

Hereinafter, a signal processing procedure of an uplink shared channel (hereinafter, referred to as 'UL-SCH') may be applied to one or more transport channels or control information types.

Referring to FIG. 5, the UL-SCH transmits data to a coding unit in the form of a transport block (TB) once every transmission time interval (TTI).

CRC parity bits p ₀ , p ₁ , p ₂ , p ₃ , in bits a ₀ , a ₁ , a ₂ , a ₃ , ..., a _{A -1} of the transport block received from the upper layer. .., p _{L - 1} is attached (S5010). In this case, A is the size of the transport block, L is the number of parity bits. The input bits with the CRC appended are b ₀ , b ₁ , b ₂ , b ₃ , ..., b _B-1 . In this case, B represents the number of bits of the transport block including the CRC.

b ₀ , b ₁ , b ₂ , b ₃ , ..., b _{B - 1} is segmented into several code blocks (CBs) according to TB size, and CRC is divided into several divided CBs. Is attached (S5020). After code block division and CRC attachment, the bits are _equal to c ₀ , c ₁ , c ₂ , c ₃ , ..., c _{r (Kr-1)} . Where r is the number of code blocks (r = 0, ..., C-1), and Kr is the number of bits according to code block r. In addition, C represents the total number of code blocks.

Subsequently, channel coding is performed (S5030). The output bit after channel coding is

Same as In this case, i is an encoded stream index and may have a value of 0, 1, or 2. Dr represents the number of bits of the i th coded stream for the code block r. r is a code block number (r = 0, ..., C-1), and C represents the total number of code blocks. Each code block may be encoded by turbo coding, respectively.

Next, rate matching is performed (S5040). Bits after rate matching

Same as In this case, r is the number of code blocks (r = 0, ..., C-1), and C represents the total number of code blocks. Er represents the number of rate matched bits of the r th code block.

Subsequently, concatenation between code blocks is performed again (S5050). The bits after the concatenation of the code blocks are performed are equal to f ₀ , f ₁ , f ₂ , f ₃ , ..., f _{G -1} . In this case, G represents the total number of encoded bits for transmission, and when the control information is multiplexed with the UL-SCH transmission, the number of bits used for transmission of the control information is not included.

On the other hand, when control information is transmitted in the PUSCH, channel coding is independently performed for the control information CQI / PMI, RI, and ACK / NACK (S5060, S5070, and S5080). Since different coded symbols are allocated for transmission of each control information, each control information has a different coding rate.

In the time division duplex (TDD), two modes of ACK / NACK feedback mode and ACK / NACK bundling and ACK / NACK multiplexing are supported by higher layer configuration. For ACK / NACK bundling, the ACK / NACK information bit is composed of 1 bit or 2 bits, and for ACK / NACK multiplexing, the ACK / NACK information bit is composed of 1 to 4 bits.

After the step of combining between code blocks in step S5050, the coded bits f ₀ , f ₁ , f ₂ , f ₃ , ..., f _{G - 1} of the UL-SCH data and the coded bits of CQI / PMI

Multiplexing is performed (S5090). The multiplexed result of the data and CQI / PMI

Same as At this time,

Denotes a column vector having a length (Q _m N _L ).

ego,

to be.

N _L represents the number of layers to which the UL-SCH transport block is mapped, and H represents the total number of encoded bits allocated for UL-SCH data and CQI / PMI information to the N _L transport layers to which the transport block is mapped. Indicates.

Subsequently, the multiplexed data, CQI / PMI, separately channel-coded RI, and ACK / NACK are channel interleaved to generate an output signal (S5100).

FIG. 6 shows an example of a signal processing procedure of a downlink shared channel which is a transport channel in a wireless communication system to which the present invention can be applied.

Hereinafter, a signal processing process of a downlink shared channel (hereinafter, referred to as 'DL-SCH') may be applied to one or more transport channels or control information types.

First, since steps S6010 to S6050 are the same as those of steps S5010 to S5050 of FIG. 5, description thereof will be omitted.

The combined code blocks are encoded and encoded according to a coding scheme determined by an encoder. The coded data is called a codeword, and codeword b may be expressed as in Equation 1.

In Equation 1, q is a codeword index,

Is the number of bits of the q codeword.

Thereafter, the codeword is scrambling by the scrambling sequence (S6060). The scrambled codeword may be expressed as Equation 2 below.

The codeword is modulated by a modulator into a symbol representing a position on a signal constellation (S6070). The modulation scheme is not limited and may be m-Phase Shift Keying (m-PSK) or m-Quadrature Amplitude Modulation (m-QAM). For example, m-PSK may be BPSK, QPSK or 8-PSK. m-QAM may be 16-QAM, 64-QAM or 256-QAM.

A codeword modulated by a symbol on the signal constellation may be expressed as in Equation 3.

In equation (3)

Is the number of symbols in the codeword.

Modulation symbols for each code word are mapped to one or more layers (S6080).

A layer is defined as an information path input to a precoder. The symbol x input to the path of each antenna may be expressed as in Equation 4.

In equation (4)

to be. v means number of layers,

Denotes the number of modulation symbols per layer.

In a single antenna transmission, a single layer v = 1 is used, and a mapping for a single layer is defined as in Equation 5 below.

At this time,

to be.

For spatial multiplexing, codewords may be hierarchically mapped according to Table 3 below.

For transmit diversity, codewords may be layer mapped according to Table 4 below.

In this case, one codeword is used, and the layer number v is equal to the number P of antennas used for transmission of the physical channel.

Thereafter, the codeword is precoded by the precoder (S6090).

Specifically, the information path before the precoder may be referred to as a virtual antenna or a layer. The precoder processes input symbols in a MIMO scheme according to multiple transmit antennas. For example, the precoder may use codebook based precoding. The precoder distributes antenna specific symbols to the subcarrier mapper of the path of the antenna. Each information path sent by a precoder to one antenna through one subcarrier mapper is called a stream. This may be referred to as a physical antenna.

The signal y ^(p) (i) sent to each antenna port p may be expressed by Equation 6 below.

The subcarrier mapper assigns input symbols to the appropriate subcarriers and multiplexes them according to the user. Thereafter, an OFDM signal is transmitted through each antenna port through a procedure of mapping to resource elements (S6100).

That is, the OFDM signal generator outputs an OFDM symbol by modulating the input symbol by the OFDM scheme. The OFDM signal generator may perform an inverse fast fourier transform (IFFT) on the input symbol, and a cyclic prefix (CP) may be inserted into the time domain symbol on which the IFFT is performed. OFDM symbols are transmitted through each transmit antenna.

In a MIMO system, the transmitter can operate in two modes. One is SCW mode and the other is MCW mode. In the SCW mode, transmission signals transmitted through the MIMO channel have the same data rate. In the MCW mode, data transmitted through the MIMO channel may be independently encoded, so that transmission signals may have different transmission rates. The MCW mode operates when the rank is two or more.

When data is generated and transmitted using the above method, modulation is performed in the order of code blocks, and since the corresponding symbols are sequentially mapped to resource elements according to the mapping method, bits between code blocks cannot obtain channel coding gains. .

In this case, when the number of OFDM symbols occupied by one code block decreases due to an increase in traffic RB, if a large number of errors occur in a specific OFDM symbol, an appropriate coding gain may not be obtained, thereby degrading overall performance (for example, BLER). There is a problem.

In order to solve this problem, the present invention proposes a method of interleaving a code block bit by bit when generating data.

7 shows an example of a resource element mapping method to which the present invention can be applied.

Referring to FIG. 7, the OFDM system may be classified into (a) frequency-first mapping and (b) time-first mapping according to an order of mapping transmission bits to resource elements.

Each of these two mapping methods has advantages and disadvantages. First, in the case of the frequency-first mapping illustrated in FIG. 7A, since the mapping is performed first in the frequency domain, the decoding is faster than the time-first mapping for the same code block size.

However, when a large performance degradation occurs in a specific OFDM symbol in the time domain, since the gain of channel coding for the time domain is reduced, an error occurs in a specific code block, thereby degrading the overall BLER performance.

In the case of the time-first mapping shown in FIG. 7B, since the mapping is performed first in the time domain, the above performance deterioration can be overcome. However, since decoding is possible after receiving the entire subframe, decoding is relatively It has the disadvantage of being slow.

Reference signal ( RS : Referen ce Signal)

Since data is transmitted over a wireless channel in a wireless communication system, the signal may be distorted during transmission. In order to correctly receive the distorted signal at the receiving end, the distortion of the received signal must be corrected using the channel information. In order to detect channel information, a signal transmission method known to both a transmitting side and a receiving side and a method of detecting channel information using a distorted degree when a signal is transmitted through a channel are mainly used. The above-mentioned signal is called a pilot signal or a reference signal (RS).

In addition, in recent years, when transmitting a packet in most mobile communication systems, a method of improving transmission / reception data efficiency by adopting a multiplexing antenna and a multiplexing antenna is avoided from using one transmitting antenna and one receiving antenna. use. When transmitting and receiving data using multiple input / output antennas, a channel state between a transmitting antenna and a receiving antenna must be detected in order to receive a signal accurately. Therefore, each transmit antenna must have a separate reference signal.

In a mobile communication system, RS can be classified into two types according to its purpose. There are RSs for channel information acquisition and RSs used for data demodulation. Since the former has a purpose for the UE to acquire channel information on the downlink, it should be transmitted over a wide band, and a UE that does not receive downlink data in a specific subframe should be able to receive and measure its RS. It is also used for measurements such as handover. The latter is an RS that the base station sends along with the corresponding resource when the base station transmits the downlink, and the UE can estimate the channel by receiving the RS, and thus can demodulate the data. This RS should be transmitted in the area where data is transmitted.

The downlink reference signal is one common reference signal (CRS: common RS) for acquiring information on channel states shared by all terminals in a cell, measurement of handover, etc. and a dedicated reference used for data demodulation only for a specific terminal. There is a signal (DRS: dedicated RS). Such reference signals may be used to provide information for demodulation and channel measurement. That is, DRS is used only for data demodulation and CRS is used for both purposes of channel information acquisition and data demodulation.

The receiving side (i.e., the terminal) measures the channel state from the CRS and transmits an indicator related to the channel quality such as the channel quality indicator (CQI), precoding matrix index (PMI) and / or rank indicator (RI). Feedback to the base station). CRS is also referred to as cell-specific RS. On the other hand, a reference signal related to feedback of channel state information (CSI) may be defined as CSI-RS.

The DRS may be transmitted through resource elements when data demodulation on the PDSCH is needed. The UE may receive the presence or absence of a DRS through a higher layer and is valid only when a corresponding PDSCH is mapped. The DRS may be referred to as a UE-specific RS or a demodulation RS (DMRS).

8 illustrates a reference signal pattern mapped to a downlink resource block pair in a wireless communication system to which the present invention can be applied.

Referring to FIG. 8, a downlink resource block pair may be represented by 12 subcarriers in one subframe x frequency domain in a time domain in which a reference signal is mapped. That is, one resource block pair on the time axis (x-axis) has a length of 14 OFDM symbols in case of normal cyclic prefix (normal CP) (in case of FIG. 5 (a)), and an extended cyclic prefix ( extended CP: Extended Cyclic Prefix) has a length of 12 OFDM symbols (in case of FIG. 5 (b)). The resource elements (REs) described as '0', '1', '2' and '3' in the resource block grid are determined by the CRS of the antenna port indexes '0', '1', '2' and '3', respectively. The location of the resource element described as 'D' means the location of the DRS.

Hereinafter, the CRS will be described in more detail. The CRS is used to estimate a channel of a physical antenna and is distributed in the entire frequency band as a reference signal that can be commonly received to all terminals located in a cell. That is, this CRS is a cell-specific signal and is transmitted every subframe for the wideband. In addition, the CRS may be used for channel quality information (CSI) and data demodulation.

CRS is defined in various formats depending on the antenna arrangement at the transmitting side (base station). In a 3GPP LTE system (eg, Release-8), RS for up to four antenna ports is transmitted according to the number of transmit antennas of a base station. The downlink signal transmitting side has three types of antenna arrangements such as a single transmit antenna, two transmit antennas, and four transmit antennas. For example, if the number of transmitting antennas of the base station is two, CRSs for antenna ports 0 and 1 are transmitted, and if four, CRSs for antenna ports 0 to 3 are transmitted.

If the base station uses a single transmit antenna, the reference signal for the single antenna port is arranged.

When the base station uses two transmit antennas, the reference signals for the two transmit antenna ports are arranged using time division multiplexing (TDM) and / or FDM frequency division multiplexing (FDM) scheme. That is, the reference signals for the two antenna ports are assigned different time resources and / or different frequency resources so that each is distinguished.

In addition, when the base station uses four transmit antennas, reference signals for the four transmit antenna ports are arranged using the TDM and / or FDM scheme. The channel information measured by the receiving side (terminal) of the downlink signal may be transmitted by a single transmit antenna, transmit diversity, closed-loop spatial multiplexing, open-loop spatial multiplexing, or It may be used to demodulate data transmitted using a transmission scheme such as a multi-user MIMO.

When a multiple input / output antenna is supported, when a reference signal is transmitted from a specific antenna port, the reference signal is transmitted to a location of resource elements specified according to a pattern of the reference signal, and the location of resource elements specified for another antenna port. Is not sent to. That is, reference signals between different antennas do not overlap each other.

The rules for mapping CRSs to resource blocks are defined as follows.

In Equation 1, k and l represent a subcarrier index and a symbol index, respectively, and p represents an antenna port.

Denotes the number of OFDM symbols in one downlink slot,

Denotes the number of OFDM symbols in one downlink slot,

Represents a cell ID. mod stands for modulo operation. The position of the reference signal depends on the v _shift value in the frequency domain. Since v _shift is dependent on the cell ID, the position of the reference signal has various frequency shift values according to the cell.

More specifically, the position of the CRS may be shifted in the frequency domain according to the cell in order to improve channel estimation performance through the CRS. For example, when reference signals are located at intervals of three subcarriers, reference signals in one cell are allocated to the 3k th subcarrier, and reference signals in another cell are allocated to the 3k + 1 th subcarrier. In terms of one antenna port, the reference signals are arranged at six resource element intervals in the frequency domain, and are separated at three resource element intervals from the reference signal allocated to another antenna port.

In the time domain, reference signals are arranged at constant intervals starting from symbol index 0 of each slot. The time interval is defined differently depending on the cyclic prefix length. In the case of the normal cyclic prefix, the reference signal is located at symbol indexes 0 and 4 of the slot, and in the case of the extended cyclic prefix, the reference signal is located at symbol indexes 0 and 3 of the slot. The reference signal for the antenna port having the maximum value of two antenna ports is defined in one OFDM symbol. Thus, for four transmit antenna transmissions, the reference signals for reference signal antenna ports 0 and 1 are located at symbol indices 0 and 4 ( symbol indices 0 and 3 for extended cyclic prefix) of slots, The reference signal for is located at symbol index 1 of the slot. The positions in the frequency domain of the reference signal for antenna ports 2 and 3 are swapped with each other in the second slot.

In more detail with respect to DRS, DRS is used to demodulate data. Precoding weights used for a specific terminal in multiple I / O antenna transmission are used without change to estimate the corresponding channel by combining with the transmission channel transmitted from each transmission antenna when the terminal receives the reference signal.

The 3GPP LTE system (eg, Release-8) supports up to four transmit antennas and a DRS for rank 1 beamforming is defined. The DRS for rank 1 beamforming also indicates a reference signal for antenna port index 5.

The rules for mapping DRS to resource blocks are defined as follows. Equation 8 shows a case of a general cyclic prefix, and Equation 9 shows a case of an extended cyclic prefix.

In Equations 2 and 3, k and l represent subcarrier indexes and symbol indexes, respectively, and p represents an antenna port.

Denotes the resource block size in the frequency domain and is expressed as the number of subcarriers. n _PRB represents the number of physical resource blocks.

Denotes a frequency band of a resource block for PDSCH transmission. ns represents the slot index,

Represents a cell ID. mod stands for modulo operation. The position of the reference signal depends on the v _shift value in the frequency domain. Since v _shift is dependent on the cell ID, the position of the reference signal has various frequency shift values according to the cell.

LTE system evolution In the advanced LTE-A system, it should be designed to support up to eight transmit antennas in the downlink of the base station. Therefore, RS for up to eight transmit antennas must also be supported. Since the downlink RS in the LTE system defines only RSs for up to four antenna ports, when the base station has four or more up to eight downlink transmit antennas in the LTE-A system, RSs for these antenna ports are additionally defined. Must be designed. RS for up to eight transmit antenna ports must be designed for both the RS for channel measurement and the RS for data demodulation described above.

One of the important considerations in designing the LTE-A system is backward compatibility, that is, the LTE terminal must work well in the LTE-A system, and the system must also support it. From an RS transmission point of view, an RS for an additional up to eight transmit antenna ports should be additionally defined in the time-frequency domain in which CRS defined in LTE is transmitted every subframe over the entire band. In the LTE-A system, when RS patterns of up to eight transmit antennas are added to all bands in every subframe in the same manner as the CRS of the existing LTE, the RS overhead becomes excessively large.

Accordingly, the newly designed RS in the LTE-A system is divided into two categories, RS for channel measurement purpose (CSI-RS: Channel State Information-RS, Channel State Indication-RS, etc.) for selection of MCS, PMI, etc. And RS (Data Demodulation? RS) for data demodulation transmitted through 8 transmit antennas.

CSI-RS for the purpose of channel measurement has a feature that is designed for channel measurement-oriented purposes, unlike the conventional CRS is used for data demodulation at the same time as the channel measurement, handover, and the like. Of course, this may also be used for the purpose of measuring handover and the like. Since the CSI-RS is transmitted only for the purpose of obtaining channel state information, unlike the CRS, the CSI-RS does not need to be transmitted every subframe. In order to reduce the overhead of the CSI-RS, the CSI-RS is transmitted intermittently on the time axis.

The DM RS is transmitted to the UE scheduled in the corresponding time-frequency domain for data demodulation. That is, the DM-RS of a specific UE is transmitted only in a region where the UE is scheduled, that is, a time-frequency region in which data is received.

In the LTE-A system, the eNB should transmit CSI-RS for all antenna ports. Transmitting CSI-RS for each subframe for up to 8 transmit antenna ports has a disadvantage in that the overhead is too large. Therefore, the CSI-RS is not transmitted every subframe but is transmitted intermittently on the time axis. Can be reduced. That is, the CSI-RS may be periodically transmitted with an integer multiple of one subframe or may be transmitted in a specific transmission pattern. At this time, the period or pattern in which the CSI-RS is transmitted may be set by the eNB.

In order to measure the CSI-RS, the UE must transmit the CSI-RS index of the CSI-RS for each CSI-RS antenna port of the cell to which it belongs, and the CSI-RS resource element (RE) time-frequency position within the transmitted subframe. , And information about the CSI-RS sequence.

 In the LTE-A system, the eNB should transmit CSI-RS for up to eight antenna ports, respectively. Resources used for CSI-RS transmission of different antenna ports should be orthogonal to each other. When an eNB transmits CSI-RSs for different antenna ports, the CSI-RSs for each antenna port may be mapped to different REs so that these resources may be orthogonally allocated in the FDM / TDM manner. Alternatively, the CSI-RSs for different antenna ports may be transmitted in a CDM scheme that maps to orthogonal codes.

When the eNB informs its cell UE of the information about the CSI-RS, it is necessary to first inform the information about the time-frequency to which the CSI-RS for each antenna port is mapped. Specifically, the subframe numbers through which the CSI-RS is transmitted, or the period during which the CSI-RS is transmitted, the subframe offset through which the CSI-RS is transmitted, and the OFDM symbol number where the CSI-RS RE of a specific antenna is transmitted, and the frequency interval (spacing), the RE offset or shift value in the frequency axis.

Phase Compensation Reference Signal Signal: PCRS )

Hereinafter, the PCRS will be described in detail.

DL PCRS  step

If the UE detects an xPDCCH with DCI format B1 or B2 in subframe n intended for it, the UE receives DL PCRS at the PCRS antenna port indicated in the DCI at the corresponding subframe.

UL PCRS  step

If the UE detects an xPDCCH with DCI format A1 or A2 in subframe n intended for it, then the UE is the same one as the assigned DM-RS antenna port indicated in DCI except the conditions (condition 1 and condition 2) below. Alternatively, two PCRS antenna ports are used to transmit UL PCRS in subframe n + 4 + m + 1.

Condition 1: If the Dual PCRS field of the detected DCI is set to '1' and the number of DM-RS ports assigned to the xPUSCH is '1', then the UE assigns the assigned DM-RS antenna port indicated in the DCI. And UL PCRS in subframe n + 4 + m + 1 using the same PCRS port as the additional PCRS antenna port having the same subcarrier location as the particular PCRS antenna port.

Condition 2: The relative transmit power ratio of PCRS and xPUSCH is determined by the transmission scheme defined by Table 3 below.

Table 5 shows an example of the relative transmit power ratio of PCRS and xPUSCH on a given layer.

Hereinafter, the PCRS will be described in more detail.

The PCRS associated with the xPUSCH is transmitted at (1) antenna port (p) p∈ {40,41,42,43}, and (2) present and only compensates for phase noise if the xPUSCH transmission is associated with the corresponding antenna port. Is a valid criterion for (3) is transmitted only on the physical resource blocks and symbols to which the corresponding xPUSCH is mapped.

sequence  Sequence generation

For any antenna port of p ∈ {40, 41, 42, 43}, the reference signal sequence r (m) is defined as in Equation 10 below.

A pseudo-random sequence c (i) is defined by a gold sequence of length-31, and a pseudo random sequence generator is initialized at the beginning of each subframe, as shown in equation (11).

The quantity (i = 0, 1) is given by

-

, if

If no value for is provided by the upper layer.

-

, if

If no value for is provided by the upper layer.

The value of n _SCID is 0 unless otherwise specified. For xPUSCH transmission, n _SCID is given by the DCI format associated with the xPUSCH transmission.

Resource element Mapping (Mapping to resource elements)

For the antenna port p∈ {40,41,42,43}, in the physical resource block having the frequency domain index n_PRB allocated for the corresponding xPUSCH transmission, a part of the reference signal sequence r (m) is

Complex-value modulation symbol for the corresponding xPUSCH symbols in the subframe according to

Is mapped to.

Starting Physical Resource Block Index at xPUSCH Physical Resource Allocation

And the number of xPUSCH physical resource blocks

For, the resource element (k, l ') for one subframe is given by Equation 12 below.

In Equation 12,

L 'represents a symbol index in one subframe,

Denotes the last symbol index of the xPUSCH for a given subframe.

The resource element (k, l ') used for transmission of UE specific PCRS from one UE on any antenna port in set S is not used for transmission of xPUSCH on any antenna port in the same subframe. .

Where S is {40}, {41} and {42}.

Carrier Frequency Offset Offset: CFO ) effect

Baseband signals transmitted by the transmitting end (e.g., base station) are shifted to the passband by the carrier frequency generated by the oscillator, and signals transmitted through the carrier frequency are transmitted by the same carrier frequency by the same carrier frequency at the receiving end (e.g., terminal). Is converted to.

In this case, the signal received by the receiver may include distortion associated with the carrier.

As one example of such distortion, there may be a distortion phenomenon caused by the difference between the carrier frequency of the transmitter and the carrier frequency of the receiver.

The reason for such carrier frequency offset is that the oscillators used at the transmitter and the receiver are not the same or the Doppler frequency transition occurs as the terminal moves.

Here, the Doppler frequency is proportional to the moving speed and the carrier frequency of the terminal and is defined as in Equation 13 below.

In Equation 13,

Denotes the carrier frequency, the Doppler frequency, the movement speed of the terminal, and the speed of light, respectively.

In addition, the normalized carrier frequency offset ε is defined as in Equation 14 below.

In Equation 14,

Denotes a carrier frequency offset normalized to a carrier frequency offset, a subcarrier spacing, and a subcarrier spacing in order.

If there is a carrier frequency offset, the received signal in the time domain is the result of multiplying the transmitted signal by the phase rotation, and the received signal in the frequency domain is the result of shifting the transmitted signal in the frequency domain.

In this case, all other subcarrier (s) are affected, resulting in inter-carrier-interference (ICI).

That is, when a decimal carrier frequency offset occurs, the received signal in the frequency domain is expressed by Equation 15 below.

Equation 15 shows a received signal having a CFO in the frequency domain.

In Equation 15,

Denote subcarrier index, symbol index, FFT size, received signal, transmitted signal, frequency response, ICI due to CFO, and white noise in order.

As defined in Equation 9, when the carrier frequency offset exists, the amplitude and phase of the k-th subcarrier are distorted, and it can be seen that interference by adjacent subcarriers occurs.

In this case, when there is a carrier frequency offset, interference by adjacent subcarriers may be given by Equation 16 below.

Equation 16 shows the ICI caused by the CFO.

Phase Noise Effect

As previously discussed, the baseband signal transmitted by the transmitter is shifted to the passband by the carrier frequency generated by the oscillator, and the signal transmitted through the carrier frequency is converted into the baseband signal by the same carrier frequency at the receiver.

Here, the signal received by the receiver may include distortion associated with the carrier wave.

As an example of such a distortion phenomenon, phase noise generated due to unstable characteristics of an oscillator used in a transmitter and a receiver may be mentioned.

This phase noise refers to the frequency fluctuating with time around the carrier frequency.

This phase noise is a random process with zero mean and is modeled as a Wiener process and affects the OFDM system.

In addition, as shown in FIG. 6 below, the phase noise tends to increase as the frequency of the carrier increases.

This phase noise tends to be characterized by a power spectral density with the same oscillator.

9 shows an example of a power spectral density of an oscillator.

As such, the distortion of the signal due to the phase noise appears in the form of a common phase error (CPE) and inter-carrier interference (ICI) in an OFDM system.

Equation 17 below shows the effect of the phase noise on the received signal of the OFDM system. That is, Equation 17 represents a received signal having phase noise in the frequency domain.

In Equation 17,

Indicates the subcarrier index, symbol index, FFT size, received signal, transmitted signal, frequency response, common phase error due to phase noise, inter-carrier interference due to phase noise, white noise, and phase rotation due to phase noise, respectively. .

Accordingly, the present invention proposes a method of interleaving in units of bits when generating data and a PCRS transmission method for demodulating data in order to compensate for such obstacles caused by phase noise.

10 and 11 illustrate an example of an interleaving method in a concatenation step to which the invention can be applied.

10 and 11, the transmitting apparatus may interleave code blocks bit by bit in the step of combining the code blocks in the procedure described with reference to FIG. 6.

FIG. 10 illustrates an example of performing interleaving on the entire code blocks in units of 1 bit.

Specifically, as described above, the transmitting apparatus segments the transport blocks into code blocks having a predetermined size and attaches CRCs to the respective code blocks.

Thereafter, the transmitting apparatus interleaves all the divided code blocks in units of 1 bit according to Equation 18 below.

In Equation 18, C and E _r represent the number of code blocks and the number of output bits after rate matching of the r th code block, respectively.

In addition, E _max means the maximum value of that represents the number of bits after rate matching for each code block.

In addition, r means the index of the code block, j means a bit index in the code block.

As shown in Equation 18 and FIG. 10, the bits of each of the code blocks are interleaved with each other in the order that the indexes of the code blocks increase.

In FIG. 10, i, j, and b (i, j) mean a j-th bit of a code block index, a bit index, and an i-th code block, respectively.

For example, the '1' to 'j' bits of each code block are interleaved with each other in order of increasing code block index.

FIG. 11 illustrates an example of performing interleaving on all code blocks in a specific bit unit.

That is, unlike FIG. 11, the divided code blocks are interleaved in a specific bit unit as shown in Equation 19 below instead of 1 bit unit.

In Equation 19, B means a bit unit that is interleaved.

As shown in Equation 19 and FIG. 11, the bits of each of the code blocks are interleaved with each other in a specific bit unit in order of increasing index of the code block.

For example, when interleaved in units of 4-bits, as shown in FIG. 11, after the first to fourth bits of the '1' th code block among the divided code blocks, one of the '2' th code blocks is shown. The fourth to fourth bits are mapped.

Through this method, even if a large error occurs in a specific symbol and data is lost, only a part of a specific code block is lost, thereby preventing the entire code block from being lost.

12 and 13 illustrate another example of an interleaving method in a concatenation step to which the present invention can be applied.

12 and 13, the transmitting apparatus may interleave code blocks in units of bits according to groups in the step of combining the code blocks in the procedure described with reference to FIG. 6.

In detail, when the entire code blocks are interleaved in units of bits, the decoding time may increase because the receiving apparatus needs to receive and decode all the code blocks because the entire code blocks are interleaved.

Therefore, when fast decoding is required for each code block, the decoding time can be reduced by grouping the code blocks into several groups and performing interleaving bit by bit in a manner similar to the interleaving described with reference to FIGS. 10 and 11. .

In FIG. 12 and FIG. 13, Q represents the number of grouped code blocks.

FIG. 12 illustrates an example of performing interleaving in units of 1 bit for each code block group including Q code blocks.

Specifically, as described above, the transmitting apparatus segments the transport blocks into code blocks having a predetermined size and then groups the code blocks into a specific number.

In this case, the CRC for checking an error of data may be attached to each code block or may be attached to a code block group consisting of a specific number of code blocks.

Thereafter, the transmitting apparatus interleaves the divided code blocks in units of 1 bit according to Equation 20 below for each code block group.

As shown in Equation 19 and FIG. 12, the divided code blocks are grouped into one or multiple code block groups, and the bits of each of the code blocks are interleaved with each other in the order that the indexes of the code blocks increase for each code block group. do.

For example, as shown in FIG. 12, the code blocks composed of 'Q' code blocks are arranged in order of increasing code block indexes from '1' to 'j' bits of each code block for each code block group. Accordingly interleaved with each other.

FIG. 13 illustrates an example of performing interleaving on all code blocks in a specific bit unit.

That is, differently from FIG. 12, grouped code blocks are not interleaved but are interleaved in a specific bit unit as shown in Equation 21 below.

In Equation 21, B means a bit unit that is interleaved.

As shown in Equation 21 and FIG. 13, the bits of each of the code blocks are interleaved with each other in a specific bit unit in order of increasing index of the code block.

For example, when interleaved in 4-bit units, as shown in FIG. 13, the first to fourth bits after the code block having the lowest index value among the 'Q' code blocks constituting the code block group In turn, four bits of the code block having the next index value are mapped.

In this way, since interleaving is performed for a specific number of code blocks, the receiving device may perform decoding even without receiving all code blocks. Therefore, there is an effect that the decoding time of each code block received at the receiving device is reduced.

14 shows an example of a method of adding a CRC to a code block to which the present invention can be applied.

FIG. 14A illustrates an example of adding an additional CRC bit to each code block divided in the transport block, and FIG. 14B groups a predetermined number of code blocks divided in the transport block. An example of adding a CRC bit for each grouped code block group is shown.

When the transport block is divided into a plurality of code blocks, the CRC bit for error checking may be additionally inserted into the divided code block as well as the transport block.

In this case, the added CRC bit may be inserted into a code block divided by various methods.

For example, as shown in FIG. 14A, when a transport block is divided into a plurality of code blocks because the transport block has a predetermined size or more, a CRC bit may be inserted for each code block to be divided.

However, when the size of the transport block is large, a large number of code blocks can be generated from the transport block. In this case, if a CRC bit for error checking is added for each code block, the coding rate may increase due to an increase of an additional CRC bit.

As another example, as shown in FIG. 14B, a plurality of code blocks may be grouped into one code block group, and a CRC bit may be added to each grouped code block group.

That is, when interleaving between code blocks is performed for each code block group including a plurality of code blocks described with reference to FIGS. 12 and 13, a CRC bit may be added for each code block group.

In this case, unlike in FIG. 14A, an increase in a coding rate due to an increase in an additional CRC bit may be reduced.

FIG. 14B illustrates an example in which a code block group is composed of three code blocks.

In the example of FIG. 14A, the CRC bit when the additional CRC bit is inserted is 24 * 6 = 144 bits. However, in the example of FIG. 14B, when the additional CRC bit is inserted, the CRC bit is 24 * 2 = 48 bits.

A method of inserting an additional CRC bit in the same manner as in FIG. 14B may be fixedly defined in the system or may be signaled to the UE through RRC / DCI.

For example, when fixedly defined in the system, the number of code blocks constituting the code block group may be specified as a predetermined number.

A code block group consisting of a predetermined number of code blocks is added with a CRC bit for each code block group and interleaved through the interleaving method described above.

When signaled through RRC / DCI, the transmitting device may explicitly or implicitly inform the receiving device of how the additional CRC bit is inserted.

For example, the transmitting device may explicitly inform the receiving device of how the additional CRC bit is inserted by transmitting information indicating that the additional CRC bit is defined for each code block group interleaved.

Alternatively, the transmitting device transmits the use of the interleaving method and / or the size of the code block group described with reference to FIG. 12 or 13 to the receiving device through RRC / DCI, and the receiving device transmits additional CRC bits through the code block group. You can see implicitly that it is inserted every time.

According to another embodiment of the present invention, after the code block concatenation step of step S6050 of FIG. 6, interleaving may be performed through a method similar to the interleaving method between the code blocks described with reference to FIGS. 10 to 13.

For example, in the code block concatenation step, interleaving described with reference to FIGS. 10 to 13 may not be performed, and inter code interleaving may be performed after the code block concatenation step.

Alternatively, after interleaving described with reference to FIGS. 10 to 13 is performed in the code block concatenation step, interleaving between code blocks may be additionally performed after the code block concatenation step.

15 and 16 illustrate an example of an interleaving method of modulated code blocks to which the present invention can be applied.

Referring to FIGS. 15 and 16, the transmitting apparatus may interleave code blocks in symbol units after a modulation step of the procedure described with reference to FIG. 6.

FIG. 15 illustrates an example of performing interleaving on the entire code blocks in units of one symbol.

In detail, after the modulation step, the transmitting apparatus interleaves all modulated code blocks in units of one symbol according to Equation 22 below.

In FIG. 15 and Equation 22, N _r , N _sym , and N _cb refer to a maximum value of N _r and a code block number, respectively, which mean the number of modulated symbols and the number of modulated symbols of the r th code block. i, j, s (i, j) mean a modulated symbol index, a code block index, and a j-th modulated symbol of an i-th code block, respectively.

As shown in Equation 22 and FIG. 15, the symbols of each of the code blocks are interleaved with each other in order of increasing index of the code block.

For example, the 'j' th symbols from the symbol having the lowest index of each code block are interleaved with each other in the order of increasing the code block index.

FIG. 16 illustrates an example of performing interleaving for all code blocks in a specific symbol unit.

That is, unlike FIG. 15, the divided code blocks are interleaved in a specific symbol unit as shown in Equation 23 below instead of 1 symbol unit.

In Equation 23, N _sg means a symbol unit interleaved.

As shown in Equation 23 and FIG. 16, the modulated code blocks are interleaved with each other in a specific symbol unit in order of increasing index of the code block.

For example, in the case of interleaving in units of 4 symbols, as shown in FIG. 16, after the '4' symbol from the '1' symbol of the '1' th code block among the modulated code blocks, the '2' th The '1' symbol from the '1' symbol of the code block is mapped.

17 and 18 show another example of an interleaving method of modulated code blocks to which the present invention can be applied.

Referring to FIGS. 17 and 18, after the modulation step of the procedure described with reference to FIG. 6, the transmitting apparatus may interleave code blocks in symbol units according to groups.

Specifically, in the case of interleaving the entire code blocks symbolically, similarly to the method of interleaving the entire code block bit by bit, the receiving apparatus receives all code blocks and performs decoding because the entire code blocks are interleaved. This can increase decoding time.

Therefore, when fast decoding is required for each code block, the decoding time can be reduced by grouping the code blocks into several groups and performing interleaving on a symbol basis in a manner similar to the interleaving described with reference to FIGS. 15 and 16. .

In FIG. 17 and FIG. 18, N _cbg represents the number of grouped code blocks.

FIG. 17 illustrates an example of performing interleaving by one symbol unit for each code block group including N _cbg code blocks.

Specifically, as described above, the transmitting apparatus modulates a code block and groups the code blocks into a specific number.

Thereafter, the transmitting apparatus interleaves the divided code blocks for each code block group by one symbol unit according to Equation 24 below.

Code blocks modulated as shown in Equation 24 and FIG. 17 are grouped into one or a plurality of code block groups, and symbols of each of the code blocks are interleaved with each other in order of increasing index of the code block for each code block group. do.

For example, as illustrated in FIG. 17, code blocks composed of 'N _cbg ' code blocks are code code group in order of increasing the code block index from '1' to 'j' symbols of each code block. Are interleaved with each other.

FIG. 18 illustrates an example of performing interleaving for all code blocks in a specific symbol unit.

That is, differently from FIG. 17, grouped code blocks are not interleaved but are interleaved in a specific bit unit as shown in Equation 25 below.

In Equation 25, N _sg means a symbol unit interleaved.

As shown in Equation 25 and FIG. 18, the symbols of each of the code blocks are interleaved with each other in a specific symbol unit in order of increasing index of the code block.

For example, when interleaved in units of four symbols, as shown in FIG. 18, after the first to fourth symbols of the code block having the lowest index value among the N _cbg code blocks constituting the code block group, Then, four symbols of the code block having the next index value are mapped.

In this way, since interleaving is performed for a specific number of code blocks, the receiving device may perform decoding even without receiving all code blocks. Therefore, there is an effect that the decoding time of each code block received at the receiving device is reduced.

19 illustrates an example of a reference signal defined for each layer to which the present invention can be applied.

Referring to FIG. 19, the transmission apparatus may transmit data generation and reference signals using an interleaving scheme to reduce performance degradation due to phase noise.

Specifically, phase noise in the high frequency band can cause a large performance degradation in system performance.

Therefore, when performance degradation due to phase noise is large, a reference signal for estimating and compensating for phase rotation due to phase noise is required. However, when using the aforementioned phase noise compensation reference signal (PCRS), the RS overhead may increase, and thus PCRS may be selectively used only when the influence of phase noise is large.

In particular, even in a system having the same carrier frequency, the effects of phase noise may appear differently according to transmission parameters. For example, when the MCS level is high, when the number of transmission RBs is large, when the number of code blocks is large, and / or when the interleaving method described with reference to FIGS. 10 to 18 is not used, performance degradation due to phase noise may be large. Can be.

That is, when the performance deterioration due to phase noise is large, the transmitting device signals whether to use the PCRS to the terminal using DCI / RRC so that the PCRS can be used.

At this time, whether to use the PCRS is determined by at least one of the MCS level, the number of Traffic RB, the number of transmission code block (CB), or whether the use of the interleaving method described in Figures 10 to 18.

That is, when a specific MCS level or more, a specific transmission RB number or more, a specific transmission code block number or more, and / or the interleaving method described in FIGS. 10 to 18 are not used, the transmitting device transmits the PCRS to the receiving device. Signal whether PCRS is used or not using DCI / RRC.

For example, the transmitting device may transmit control information indicating whether to transmit the PCRS to the receiving device.

When the receiver receives the PCRS based on the information transmitted through the DCI / RRC, the receiving apparatus may estimate and compensate an impairment due to phase noise using the PCRS.

19 shows an example of a PCRS defined in 2 RB units. The transmitting device transmits the PCRS to the receiving device when at least one of a specific MCS level or more, a specific transmission RB number or more, a specific transmission code block number or more, or a case in which the interleaving method described in FIGS. 10 to 18 is not used. In addition, signaling whether or not the PCRS is used by the receiving device may inform whether the PCRS is used. The terminal may estimate and compensate for impairment due to phase noise using the received PCRS.

Thus, by determining whether to use the PCRS according to the system situation and signaling from the base station to the terminal, it is possible to increase the efficiency of the system by using the PCRS only when the performance degradation due to phase noise is large.

In another embodiment of the present invention, the transmitting device may not signal whether the PCRS is transmitted to the receiving device when the PCRS is transmitted.

That is, when a specific condition is set in advance between the transmitting device and the receiving device, the transmitting device may transmit the PCRS to the receiving device without additional signaling when the specific condition is satisfied.

For example, when at least one of a predetermined MCS level or more, a specific transmission RB size or more, a specific transmission code block number or more, or inter-CB interleaving nonuse is set between the transmitting device and the receiving device, When the at least one condition among the preset conditions is satisfied, the PCRS may be transmitted to the receiving device without additional signaling.

The receiving device can compensate and estimate impairment due to phase noise using the received PCRS.

According to another embodiment of the present invention, the transmitter may selectively use the interleaving scheme described with reference to FIGS. 10 to 18 according to a transmission environment of the transmitter, and control information indicating whether the interleaving scheme described with reference to FIGS. 10 to 18 is used. Can be singnaled to the terminal through DCI / RRC.

Specifically, phase noise in the high frequency band can cause significant performance degradation in the system. At this time, the impairment of phase noise is represented by two types of common phase error and ICI that appear in the same frequency band in OFDM symbol units.

The effect of phase noise may be different in units of OFDM symbols. Therefore, the influence of phase noise in a particular OFDM symbol is large, which may cause a large performance degradation in the symbol. In addition, in the case of using the frequency-first mapping method, the gain on the time axis of channel coding is reduced, which may cause a large performance degradation.

In particular, when the partition is applied based on a specific maximum size for the entire transport block, and the frequency-first mapping method is used, the number of code blocks to be divided increases as the number of traffic RBs increases, and time within one code block is increased. Since the number of modulation symbols for obtaining a coding gain for a region decreases, performance degradation due to phase noise may increase.

Therefore, in a case where a certain MCS level or more, a specific transmission RB number, or a specific transmission CB number or more is satisfied, that is, in an environment in which the influence of phase noise can be large, the transmission apparatus may have interleaving described with reference to FIGS. 10 to 18. Scheme can be used and the receiving device can be informed that this interleaving scheme is used.

The receiving device may receive data by performing de-interleaving based on the interleaving scheme described with reference to FIGS. 10 to 18.

In this case, the transmitting device may signal whether the interleaving method is used to the receiving device by using DCI / RRC, and inform the receiving device whether to perform interleaving.

In this case, the variables used in Equations 18 to 25 may use respective values defined according to an interleaving scheme, or may adaptively select values. That is, the transmitting device may transmit information indicating whether the interleaving method described in FIGS. 10 to 18 and / or variable values according to the used interleaving method are transmitted to the receiving device.

Alternatively, the transmitting apparatus may transmit variable values according to each interleaving scheme to the receiving apparatus, but may not separately transmit information indicating whether to use the interleaving scheme described with reference to FIGS. 10 to 18.

That is, when a specific condition set in advance is satisfied between the transmitter and the receiver, the transmitter may use the interleaving method described with reference to FIGS. 10 to 18 without additional information transmission.

For example, when a specific MCS level, a specific Traffic RB number, and / or a specific transmission CB number set between the transmitting device and the receiving device are satisfied, the transmitting device may use the interleaving method described with reference to FIGS. 10 to 18 without additional signaling. Can be.

In addition, variable values according to respective interleaving schemes may be transmitted to the receiving device through DCI / RRC.

20 is a flowchart illustrating an example of a method for transmitting data by a transmitting apparatus to which the present invention can be applied.

Referring to FIG. 20, the transmission apparatus may compensate for performance degradation due to phase noise by interleaving and transmitting data by interleaving code blocks divided from a transport block.

In detail, when the size of the transport block to which the CRC is attached is greater than or equal to a specific size, the transmitting device divides the transport block into one or more code blocks as shown in FIG. 6, and each of the divided one or more code blocks. Channel coding is performed with respect to S20010 and S20020.

Thereafter, the transmitting device concatenates one or more code blocks (S20030). In this case, the transmitting apparatus may add the CRC to the code blocks through the method described with reference to FIG. 14 in the step of concatenating one or a plurality of code blocks.

Thereafter, the transmitting apparatus interleaves one or a plurality of code blocks to which the CRC is added using the interleaving method of the bit unit described with reference to FIGS. 10 to 13.

The transmitting device may additionally perform interleaving on one or more concatenated code blocks using the interleaving method in units of bits described with reference to FIGS. 10 to 13 (S20040).

Thereafter, the transmitting apparatus scrambles one or more concatenated code blocks and modulates the scrambled one or more code blocks (S20050 and S20060).

The transmitting apparatus interleaves the modulated one or more code blocks using the symbol interleaving scheme described with reference to FIGS. 15 to 18 (S20070).

Thereafter, the transmitting device transmits the interleaved symbols to the receiving device on each antenna port through steps S6080 to S6100 of FIG. 6 and through an OFDM signal generation step.

10 to 20 may be applied to downlink data transmission and reception and uplink data transmission and reception using OFDM transmission.

21 illustrates a block diagram of a wireless communication device to which the present invention can be applied.

Here, the wireless device may be a base station and a terminal, and the base station includes both a macro base station and a small base station.

As shown in FIG. 21, the base station 2110 and the UE 2120 include a communication unit (transmitter and receiver, an RF unit, 2113 and 2123), a processor 2111 and 2121, and a memory 2112 and 2122.

In addition, the base station and the UE may further include an input unit and an output unit.

The communication units 2113 and 2123, the processors 2111 and 2121, the input unit, the output unit, and the memory 2112 and 2122 are functionally connected to perform the method proposed in the present specification.

When the communication unit (transmitter / receiver unit or RF unit, 2113, 2123) receives information generated from the PHY protocol (Physical Layer Protocol), the received information is transferred to the RF-Radio-Frequency Spectrum, filtered, and amplified. ) To transmit to the antenna. In addition, the communication unit functions to move an RF signal (Radio Frequency Signal) received from the antenna to a band that can be processed by the PHY protocol and perform filtering.

The communication unit may also include a switch function for switching the transmission and reception functions.

Processors 2111 and 2121 implement the functions, processes, and / or methods proposed herein. Layers of the air interface protocol may be implemented by a processor.

The processor may be represented by a controller, a controller, a control unit, a computer, or the like.

The memories 2112 and 2122 are connected to a processor and store protocols or parameters for performing an uplink resource allocation method.

Processors 2111 and 2121 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices. The memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device. The communication unit may include a baseband circuit for processing a wireless signal. When the embodiment is implemented in software, the above technique may be implemented as a module (process, function, etc.) for performing the above-described function.

The module may be stored in memory and executed by a processor. The memory may be internal or external to the processor and may be coupled to the processor by various well known means.

The output unit (display unit or display unit) is controlled by a processor and outputs information output from the processor together with a key input signal generated at the key input unit and various information signals from the processor.

Further, for convenience of description, the drawings are divided and described, but it is also possible to design a new embodiment by merging the embodiments described in each drawing. And, according to the needs of those skilled in the art, it is also within the scope of the present invention to design a computer-readable recording medium having a program recorded thereon for executing the embodiments described above.

Orientation-based device discovery method according to the present disclosure is not limited to the configuration and method of the embodiments described as described above, the embodiments are all or part of each of the embodiments is optional so that various modifications can be made It may be configured in combination.

Meanwhile, the direction-based device search method of the present specification may be implemented as processor-readable code in a processor-readable recording medium provided in a network device. The processor-readable recording medium includes all kinds of recording devices that store data that can be read by the processor. Examples of the processor-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, and the like, and may also be implemented in the form of a carrier wave such as transmission over the Internet. . The processor-readable recording medium can also be distributed over network coupled computer systems so that the processor-readable code is stored and executed in a distributed fashion.

In addition, while the above has been shown and described with respect to preferred embodiments of the present specification, the present specification is not limited to the specific embodiments described above, the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

In addition, in this specification, both the object invention and the method invention are described, and description of both invention can be supplementally applied as needed.

The RRC connection method in the wireless communication system of the present invention has been described with reference to an example applied to the 3GPP LTE / LTE-A system, but it is possible to apply to various wireless communication systems in addition to the 3GPP LTE / LTE-A system.

Claims (20)

1. A method for transmitting data by a transmitting device in a wireless communication system,

   Dividing the transport block into one or a plurality of code blocks;

   Performing channel coding on each of the one or multiple code blocks;

   Concatenating the one or more code blocks,

   Interleaving the one or more code blocks by a specific bit unit;

   Scrambling the concatenated one or more code blocks; And

   Modulating the scrambled one or multiple code blocks.
2. The method of claim 1,

   The one or more code blocks are grouped into a certain number of groups and interleaved by groups.
3. The method of claim 2,

   Attaching a cyclic redundancy check (CRC) to each of the specific number of groups.
4. The method of claim 1,

   Interleaving the concatenated one or more code blocks on a specific bit basis.
5. The method of claim 4, wherein the interleaving comprises:

   Grouping the concatenated one or more code blocks into a specific number of groups; And

   Interleaving the grouped one or multiple code blocks by group.
6. The method of claim 1,

   Interleaving the modulated one or more code blocks on a specific symbol basis.
7. The method of claim 6, wherein the interleaving comprises:

   Grouping the modulated one or multiple code blocks into a specific number of groups; And

   Interleaving the grouped one or multiple code blocks by group.
8. The method of claim 1,

   And transmitting control information indicating whether the one or more code blocks are interleaved to a receiving device.
9. The method of claim 1,

   Transmitting control information indicating whether a reference signal for demodulating the data is transmitted according to whether one or more code blocks are interleaved; And

   If the control information indicates transmission of the reference signal, transmitting the reference signal to a receiving device.
10. The method of claim 1,

    Mapping the one or more code blocks to at least one layer;

    Precoding the one or more code blocks mapped to the at least one layer; And

    Mapping the precoded one or multiple code blocks to a transmission resource using a time priority mapping technique or a frequency priority mapping technique.
11. A transmitting device for transmitting data in a wireless communication system,

    Communication unit for transmitting and receiving a wireless signal with the outside; And

    A processor is functionally coupled with the communication unit, wherein the processor includes:

    Split the transport block into one or more code blocks,

    Performing channel coding on each of the one or multiple code blocks,

    Concatenate the one or more code blocks,

    Interleaving the one or more code blocks in a specific bit unit,

    Scrambling the concatenated one or more code blocks,

    And a transmitter for modulating the scrambled one or multiple code blocks.
12. The method of claim 11,

    The one or more code blocks are grouped into a certain number of groups and interleaved for each group.
13. The method of claim 12, wherein the processor,

    And transmitting a cyclic redundancy check (CRC) to each of the specific number of groups.
14. The method of claim 11, wherein the processor,

    And transmitting the concatenated one or more code blocks in a specific bit unit.
15. The method of claim 11, wherein the processor,

    Grouping the concatenated one or more code blocks into a specific number of groups; And

    And interleaving the grouped one or more code blocks by group.
16. The method of claim 11, wherein the processor,

    Transmitting device for interleaving the modulated one or multiple code blocks in a specific symbol unit.
17. The method of claim 16, wherein the processor,

    Group the modulated one or multiple code blocks into a specific number of groups,

    And interleaving the grouped one or more code blocks by group.
18. The method of claim 11, wherein the processor,

    And a control device for transmitting control information indicating whether the one or more code blocks are interleaved.
19. 12. The system of claim 11, wherein the processor is

    Transmit control information indicating whether a reference signal for demodulating the data is transmitted according to whether one or more code blocks are interleaved;

    And transmitting the reference signal to a receiving device when the control information indicates the transmission of the reference signal.
20. 12. The system of claim 11, wherein the processor is

    Mapping the one or more code blocks to at least one layer,

    Precoding the one or more code blocks mapped to the at least one layer,

    And transmitting the precoded one or more code blocks to a transmission resource using a time priority mapping technique or a frequency priority mapping technique.

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