KR20200029612A - Method and apparatus for transmitting and receiving uplink control information in a wireless communication system and requesting random access - Google Patents

Abstract

The present disclosure relates to a pre-5G or 5G communication system provided to support a higher data rate than a 4G (4G) communication system such as Long Term Evolution (LTE). The present disclosure provides a method for transmitting uplink control information, the method comprising: determining, by user equipment (UE), at least two carriers for uplink transmission in a cell currently connected by a UE And determining a carrier for uplink control information (UCI) transmission from at least two carriers for uplink transmission, a relative frequency occupied by the UCI on the carrier for the determined UCI transmission by the UE. Determining a domain location and a time domain start location, re-adjusting the UE's center radio frequency to the center frequency of the carrier for UCI transmission by the UE, and the relative frequency domain location and time domain start location occupied by the UCI In accordance with the step of transmitting the UCI, wherein the UE transmits and receives information on one carrier at a time. UCI can be efficiently transmitted using the present disclosure. The present disclosure further discloses a method for requesting random access, the method comprising: determining a time division duplex (TDD) uplink time domain resource; Determining a time domain resource used to transmit a narrowband physical random access channel (NPRACH) according to the TDD uplink time domain resource; Determining the time domain format for an NPRACH transmission group, wherein the time domain format includes at least two transmission units in which one NPRACH transmission group is discontinuous in the time domain and one transmission unit is one or more consecutive NPRACHs in the time domain. Configured to include symbol groups-; And in the time domain resource used to transmit the determined NPRACH, transmitting the NPRACH transmission group in time domain format. Compared to the prior art, in the present disclosure, the time domain location for transmitting the NPRACH is designed according to the characteristics of the TDD uplink time domain resource, so that the random access process can be placed within the LTE band or LTE guard band; In addition, since an NB-IoT communication system based on TDD is used, a higher utilization rate for system spectrum resources is achieved.

Description

Method and apparatus for transmitting and receiving uplink control information in a wireless communication system and requesting random access

The present disclosure relates to wireless communication, and more particularly, to a method and apparatus for transmitting and receiving uplink control information and requesting random access.

4G (4 ^th generation) to meet the traffic demand in the radio data communication system increases since the commercialization trend, efforts to develop improved 5G communication system or pre-5G communication system have been made. For this reason, a 5G communication system or a pre-5G communication system is called a 'Beyond 4G network' or a 'Post LTE system'.

In order to achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, 60 GHz band). In order to reduce radio wave propagation loss and increase transmission distance, in 5G communication systems, beamforming, massive array multiple input / output (massive MIMO), full dimensional multiple input / output (FD-MIMO), array antenna (array antenna) ), Analog beam forming, and large scale antenna technologies are being discussed.

In addition, in order to improve the system network, in the 5G communication system, an advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, D2D (device- Technological developments such as to-device communication, wireless backhaul, mobile networks, cooperative communication, coordinated multi-points (CoMP), and interference cancellation at the receiving end have been made.

In 5G systems, advanced coding modulation (ACM) technology, hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access technology filter bank multi carrier (FBMC), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) are being developed.

The present disclosure improves uplink data rates and improves uplink control information (uplink), particularly for narrowband systems operating in a time division duplex (TDD) frequency band and a frequency division duplex (FDD) frequency band. Provided is a method and apparatus for transmitting uplink control information for efficiently performing control information (UCI) transmission.

In order to achieve the above object, the present disclosure provides the following technical solutions.

A method for transmitting uplink control information, the method comprising: determining, by user equipment (user equipment), at least two carriers for uplink transmission in a cell currently connected by a UE, and uplink transmission Determining a carrier for uplink control information (UCI) transmission from at least two carriers for, Relative frequency domain location and time domain start occupied by the UCI on the carrier for the determined UCI transmission by the UE Determining a position, re-adjusting the center radio frequency of the UE to the center frequency of the carrier for UCI transmission by the UE, and transmitting UCI according to the relative frequency domain position and time domain start position occupied by the UCI It includes a step, wherein the UE transmits and receives information on one carrier at a time.

Preferably, the carrier for UCI transmission is different from the carrier used for uplink data transmission of the UE, or the carrier for UCI transmission is different from the uplink carrier corresponding to the downlink channel of the UE.

Preferably, determining, by the UE, at least two carriers for uplink transmission, by the UE, determining at least two carriers for uplink transmission according to the first signaling transmitted from the base station, or Determining an uplink carrier corresponding to a downlink anchor carrier or a carrier transmitted by the UE as a single carrier for uplink transmission by a UE, and in accordance with a second signaling transmitted from a base station or predefined And determining other carriers for uplink transmission according to the rule.

Preferably, determining the carrier for UCI transmission is to determine, by the UE, a carrier for UCI transmission according to the third signaling transmitted from the base station, where the third signaling is carriers for uplink transmission Configured to indicate a carrier for UCI transmission from-or, by the UE, determining a carrier for UCI transmission according to the first signaling or the second signaling.

Preferably, the UE determines an uplink carrier corresponding to a carrier or downlink anchor carrier in which a narrowband random access channel (NPRACH) is transmitted as one carrier for uplink transmission, and also from the base station In an environment in which other carriers for uplink transmission are determined according to the transmitted second signaling or according to a predefined rule, the UE determines a carrier for UCI transmission according to a predefined rule.

Preferably, the predefined rule is to transmit UCI on another carrier for uplink transmission or to transmit UCI on an uplink carrier corresponding to the downlink control channel of the UE.

Preferably, determining the time domain start position occupied by the UCI determines the first effective uplink transmission position starting from the end position of the downlink data channel and satisfying the specified time offset as the time domain start position. Includes, wherein the specified time offset is a preset minimum time offset, or the specified time offset is a time offset determined according to signaling transmitted from the base station.

Preferably, determining the time offset according to signaling transmitted from the base station directly determines one of the multiple time offsets as the time offset, where the multiple time offsets are absolute time offsets, or one minimum Time offset + determining the X uplink time unit as a time offset, where the X uplink time unit is determined according to signaling transmitted from the base station.

Preferably, determining the time offset according to signaling transmitted from the base station includes determining one of the time offsets set according to DCI transmitted from the base station as the time offset.

Preferably, when the UE determines the relative frequency domain position and time domain start position occupied by the UCI, the method determines the time domain length of the UCI according to the length of one UCI transmission and the number of repetitions of the UCI. Further included, wherein one UCI transmission length is one subframe or two slots.

Preferably, the number of repetitions of UCI is configured through RRC.

Preferably, the length of one subframe or two slots is 1 millisecond or 4 milliseconds.

Preferably, determining the effective uplink transmission location is to determine the uplink subframe determined according to the uplink and downlink subframe configuration in the time division duplex (TDD) system as the effective uplink transmission location, in the TDD system Determining an uplink pilot time slot (UpPTS) of an uplink and downlink subframe and a special subcarrier as an effective uplink transmission location, or according to the number of symbols included in the UpPTS of the special subframe. Or determining an effective uplink transmission location according to a special subframe configuration-when the TDD system includes two consecutive uplink subframes or an even number of consecutive uplink subframes, the uplink and the current TDD system Uplink subframe determined according to the downlink subframe configuration is effective uplink transmission Value, otherwise, the effective uplink transmission location is determined according to the number of symbols included in the UpPTS of the special subframe or the configuration of the special subframe-, Uplink Tx of the uplink subframe and the special subframe is effective. Determining as a location, or depending on a configuration configured by signaling from a base station, determining an uplink subframe as an effective uplink transmission location, each in a special subframe according to a bitmap indicator carried in signaling from a base station And determining whether the uplink carriers of the uplink and UpPTS are used as an effective uplink transmission location.

Preferably, determining the effective uplink transmission location according to the number of symbols included in the UpPTS of the special subframe, when the number of symbols included in the UpPTS is greater than a preset threshold, effectively uplinks the UpPTS and the uplink subframe. Determined as a link transmission location, otherwise, determines an uplink subframe as an effective uplink transmission location, or uplink and downlink configurations in a TDD system are designated uplink and downlink configurations, and are included in UpPTS If the number of symbols is greater than a preset threshold, UpPTS and uplink subframes are determined as effective uplink transmission locations, otherwise, uplink subframes are determined as valid uplink transmission locations.

Preferably, determining the effective uplink transmission location according to the special subframe configuration is when the current special subframe configuration is preset or a designated special subframe configuration configured by the base station, UpPTS and uplink subframe Is determined as an effective uplink transmission location, otherwise, an uplink subframe is determined as an effective uplink transmission location, or an uplink and downlink configuration in which uplink and downlink configurations in a TDD system are designated, If the current special subframe configuration is preset or designated special subframe configuration configured by the base station, UpPTS and uplink subframe are determined as effective uplink transmission locations, otherwise, the uplink subframe is valid Including determining as an uplink transmission location All.

A method for receiving uplink control information, the method comprising: determining, by a base station, at least two carriers for uplink transmission allocated to a user equipment (UE) in a cell currently connected by a UE, and uplink Determining a carrier for uplink control information (UCI) of the UE from at least two carriers for transmission, a relative frequency domain location and a time domain start location occupied by the UCI on the carrier for the determined UCI transmission, by the base station Determining, by the base station, receiving the UCI in the carrier for UCI transmission of the UE according to the relative frequency domain location occupied by the UCI and the time domain start location, wherein the UE is one at a time Send and receive information on the carrier.

Preferably, when the base station configures a carrier used by the UE to transmit UCI, the base station configures carriers used by multiple users to transmit UCI as the same carrier.

Preferably, when the base station determines the time domain start position, the base station determines the time domain start position occupied by the UCI of multiple UEs as the same position.

Preferably, when the base station determines the time domain start location, the base station determines the time domain start locations occupied by different UCIs of the UEs to the same location.

An apparatus for transmitting uplink control information, the apparatus comprising a carrier determination unit, a frequency domain and time domain determination unit and a transmission unit; The carrier determination unit is configured to determine at least two carriers for uplink transmission in a currently connected cell, and to determine a carrier for uplink control information (UCI) transmission from at least two carriers for uplink transmission, the frequency domain And the time domain determining unit is configured to be used by the user equipment (UE) to determine the relative frequency domain location and time domain starting location occupied by the UCI on the carrier for the determined UCI transmission, the transmitting unit being the center radio of the UE. Reconfigure the frequency to the center frequency of the carrier for UCI transmission, and to transmit the UCI according to the relative frequency domain position and time domain start position occupied by the UCI; The transmitting unit transmits information on one carrier at a time.

An apparatus for receiving uplink control information, the apparatus comprising a carrier determination unit, a frequency domain and time domain determination unit and a reception unit; The carrier determination unit determines at least two carriers for uplink transmission allocated to the UE in the cell currently connected by the user equipment (UE), and uplink control information (UCI) of the UE from at least two carriers for uplink transmission ) Is configured to determine a carrier for transmission-the UCI and uplink data of the UE is transmitted on different carriers-the frequency domain and time domain determination unit is a relative frequency domain occupied by the UCI on the carrier for the determined UCI transmission Configured to determine the location and time domain starting location, and the receiving unit is also configured to receive UCI in the carrier for UCI transmission of the UE according to the relative frequency domain location and time domain starting location occupied by the UCI; Here, the UE transmits information through one carrier at a time.

In addition, the present disclosure provides a method and apparatus for transmitting the center frequency of a carrier in a TDD system, which can provide a more flexible mode of operation for the TDD system, especially when a narrowband system is in-band or guard of a wideband system. For scenarios operating in the band, it is possible to efficiently improve the use of the radio frequency spectrum.

To achieve the above object, the present disclosure uses the following solutions: A method for transmitting signals in a time division duplex (TDD) narrowband system, the method being performed by a UE, the first carrier of the TDD narrowband system. Acquiring, If the uplink or downlink carrier determined as the first carrier is located in the in-band or guardband of the TDD broadband system, by the UE, acquiring the indication information of the second carrier corresponding to the first carrier Determining an offset between the first carrier and the second carrier of the TDD narrowband system according to the indication information, and determining the center frequency of the second carrier corresponding to the first carrier according to the offset and the center frequency of the first carrier Computing step, by the UE, comprising transmitting and receiving signals according to the calculated center frequency of the second carrier, wherein the first carrier If the uplink carrier, a second carrier and a downlink carrier, when the first carrier is a downlink carrier, a second carrier is an uplink carrier.

Preferably, when the first carrier is a downlink carrier, the downlink carrier is an anchor carrier or a non-anchor carrier.

Preferably, the indication information of the second carrier is configured in a system information block (SIB) or a master information block (MIB).

Preferably, the indication information of the second carrier includes at least one of the following information: offset information from the center frequency of the first carrier, information of physical resource blocks occupied by the TDD broadband system, and a position relative to the TDD broadband system. Information of CRS (cell-specific reference signal) sequence.

Preferably, the UE determines that the first carrier is located in the in-band or guard-band of the TDD broadband system, synchronization channel, master information block, system information block, UE specific radio resource control (RRC) signaling , According to one or more channels or information of physical layer indication information or media access control (MAC) layer indication information, the UE determining that the first carrier is within an in-band or guard-band of a TDD broadband system.

Preferably, when the first carrier is an uplink carrier, the uplink carrier obtained by the UE is an uplink carrier used to transmit a random access channel.

Preferably, when the first carrier is a downlink carrier, the downlink carrier obtained by the UE is located in the in-band of the TDD wideband system, and the cell ID of the TDD narrowband system and the cell ID of the TDD wideband system are the same. 2 The indication information of the carrier includes information of the CRS sequence.

Preferably, the UE transmitting or receiving signals according to the center frequency of the second carrier includes the UE re-adjusting the center radio frequency to the calculated center frequency of the second carrier, and transmitting or receiving signals.

As user equipment (UE) in a time division duplex (TDD) narrowband system, this user equipment includes an acquisition unit, a calculation unit and a transmission unit; The acquiring unit is configured to acquire the first carrier of the TDD narrowband system, and the calculating unit, if the uplink or downlink carrier determined as the first carrier is located in the in-band or guardband of the TDD broadband system, the first carrier Acquire the indication information of the second carrier corresponding to, and determine the offset between the first carrier and the second carrier of the TDD narrowband system according to the indication information, and according to the offset and the center frequency of the first carrier to the first carrier Configured to determine the center frequency of the corresponding second carrier, and the transmitting unit is configured to transmit or receive signals according to the center frequency of the second carrier calculated by the calculating unit, where the first carrier is an uplink carrier In case, the second carrier carrier is a downlink carrier; When the first carrier is a downlink carrier, the second carrier is an uplink carrier.

As can be seen from the above-described technical solutions, in the present disclosure, the UE determines at least two carriers for uplink transmission in the cell currently connected by the UE, and determines UCI from at least two carriers for uplink transmission. Determine a carrier for transmission; Here, the UE receives and transmits information through one carrier at a time. In the carrier for transmitting the determined UCI, the UE determines the relative frequency domain location and time domain start location occupied by the UCI. The UE readjusts the center radio frequency of the UE to the center frequency of the carrier for transmitting the UCI, and transmits the UCI according to the relative frequency domain location and time domain start location occupied by the UCI. In this way, the UE can support at least two uplink carriers in the same cell in order to efficiently transmit UCI.

Preferably the solutions of the present disclosure transmit UCI and uplink data on two different uplink carriers in a cell, thereby uplink data rate, especially for narrowband systems operating in the TDD frequency band and the FDD frequency band. Improve efficiently.

The solutions of the present disclosure provide a more flexible configuration for narrowband systems operating in guardband mode or inband mode, especially for narrowband systems in which anchor carriers and non-anchor carriers are transmitted in a wideband inband or guardband, This improves the use of radio spectrum resources and ensures a low complexity UE. The solutions of the present disclosure are applicable to narrowband systems operating in the TDD frequency band and FDD frequency band, particularly narrowband systems operating in the TDD frequency band.

The purpose of the present disclosure is to provide a method and user equipment for overcoming the defects of the prior art and requesting random access, which is applicable to a TDD communication system, can be deployed in an LTE band or an LTE guardband, and is a standalone TDD. It can also be used for NB-IoT systems.

To this end, the present disclosure provides a method for requesting random access, the method comprising: determining a time division duplex (TDD) uplink time domain resource, a narrowband physical random access channel according to a TDD uplink time domain resource ( Determining the time domain resource used to transmit the NPRACH), determining the time domain format of the NPRACH transmission group, wherein the time domain format includes at least two transmission units in which one NPRACH transmission group is discontinuous in the time domain. And one transmitting unit is configured to include one or more consecutive NPRACH symbol groups in the time domain-transmitting, in the time domain resource used to transmit the determined NPRACH, an NPRACH transmission group in time domain format.

Preferably, one transmission group includes a plurality of transmission units that are discontinuous in the time domain: one transmission group includes at least two transmission units that are discontinuous in the time domain.

Preferably, determining the time domain resource used to transmit the NPRACH, according to the TDD uplink time domain resource, determines a number of consecutive TDD uplink time domain sections according to the TDD uplink time domain resource. Including step, one continuous TDD uplink time domain section is configured by any one of a number of consecutive uplink subframes, or one special subframe and a plurality of consecutive uplink subframe (s). In the time domain resource used to transmit the determined NPRACH, the step of transmitting the NPRACH transmission group in the time domain format may include one transmission unit of the NPRACH transmission group, in one consecutive TDD uplink time domain section, And transmitting correspondingly.

Preferably, the step of correspondingly transmitting one transmission unit of the NPRACH transmission group in one continuous TDD uplink time domain section comprises: one transmission unit of the NPRACH transmission group, one continuous TDD uplink time domain And correspondingly transmitting in the section, where the end of this transmitting unit is located before the end of this contiguous TDD uplink time domain section.

Preferably, the step of correspondingly transmitting one transmission unit of the NPRACH transmission group in one successive TDD uplink time domain section is used to correct the time for transmitting one transmission unit and transmit correspondingly Determining a timing advance (TA); According to the TA, transmitting one transmission unit of the NPRACH transmission group in one consecutive TDD uplink time domain section.

Preferably, the TA used to correct the time for transmitting one transmission unit is determined, and according to the TA and in one consecutive TDD uplink time domain section, one transmission unit of the NPRACH transmission group is correspondingly The step of sending,

Determining the TA as Ts with m time units, and transmitting, in UpPTS and multiple consecutive uplink subframe (s) after UpPTS, one transmission unit of the NPRACH transmission group, and time for this transmission unit And correcting the domain start transmission position to the start position of Ts having m time units before UpPTS.

The end transmission position for this transmission unit in the time domain is a transmission that lasts until the first uplink subframe after UpPTS, or a transmission that lasts until the last of all consecutive uplink subframes after UpPTS, or one This includes transmissions that last for the length of the NPRACH symbol group.

Preferably, the NPRACH symbol group includes one cyclic prefix (CP) and 3 to 5 symbols, and the total length of each symbol group is 43008 * Ts or less, where 30720 * Ts = 1 ms; or,

The NPRACH symbol group includes one CP and 3 to 6 symbols, and the total length of each symbol group is 14336 Ts or less, where 30720 * Ts = 1 ms.

Preferably, the step of determining the TDD uplink time domain resource is determining the effective uplink subframe (s) as the TDD uplink time domain resource-the effective uplink subframe (s) is the received effective uplink Indicated by subframe (s) configuration information-; or

Determining subframe (s) other than the effective downlink subframe (s) as TDD uplink time domain resources, wherein the effective downlink subframe (s) is indicated by the received valid downlink subframe configuration information; or,

Determining uplink subframe (s) and uplink pilot time slot (UpPTS) as TDD uplink time domain resources-Uplink subframe (s) and UpPTS are received uplink-downlink -Indicated by configuration information.

Preferably, after the step of determining the time domain format for the NPRACH transmission group, the method includes determining a frequency domain location for transmitting the NPRACH transmission unit in a frequency-hopping transmission scheme, wherein the frequency- The frequency domain resource for hopping transmission is determined by at least one of the configured carrier location, subcarrier group location, and subcarrier location, and the frequency hopping pattern is predefined or determined by the cell ID or generated using the cell ID as a seed Determined by the random sequence to be, in the continuous TDD uplink time domain section, the step of correspondingly transmitting one transmission unit of the NPRACH transmission group, in one continuous TDD uplink time domain section and the determined NPRACH transmission unit In the frequency domain location for transmitting the NPRACH transmission group And transmitting one transmission unit.

Preferably, the time domain format further comprises that the phases between two adjacent transmission units are continuous or the phases are fixed.

Preferably, the time domain format further comprises that at least two frequency-hopping intervals between symbol groups in the NPRACH transmission group are different.

Preferably, the step of determining the TA used to correct the time for transmitting one transmission unit comprises: determining the TA used to correct the time for transmitting one transmission unit according to at least one of the following: Includes: received radio resource control (RRC) signaling, special subframe configuration information, uplink-downlink configuration information, a TA value corresponding to a preset NPRACH symbol group time-frequency format and a predetermined fixed TA value.

Preferably, in one continuous TDD uplink time domain section, correspondingly transmitting one transmission unit of the NPRACH transmission group comprises: distribution of the uplink subframe (s) and special subframe (s), corresponding Time for transmission of the first transmission unit of the NPRACH transmission group, according to any one of the number of uplink subframe (s) in the continuous TDD uplink time domain section, and information for indicating the received reference point offset Determining a starting position in the domain, and transmitting this transmitting unit in a corresponding consecutive TDD uplink time domain section.

Preferably, in one consecutive TDD uplink time domain section, correspondingly transmitting one transmission unit of the NPRACH transmission group comprises: RRC signaling received, a value corresponding to a preset NPRACH symbol group time domain format And determining a time interval between two consecutive transmission units according to any one of uplink-downlink switching periods. Determining a time domain transmission location of the second transmission unit or subsequent transmission unit (s) according to the time domain transmission location and time interval of the first transmission unit of the NPRACH transmission group; And transmitting the second transmission unit or subsequent transmission unit (s) in the corresponding consecutive TDD uplink time domain section.

Preferably, in the time domain resource used to transmit the determined NPRACH, transmitting the NPRACH transmission group in the time domain format comprises: determining the number of repetitions N for transmissions of the NPRACH transmission group, and transmitting the determined NPRACH In the time domain resource used, iteratively includes transmitting NPRACH transmission groups having a time domain format N times.

Preferably, determining the time domain format for the NPRACH transmission group includes determining the time domain format for the NPRACH transmission group according to at least one of the following parameters: TDD uplink time domain resource, uplink Link subframe configuration, special subframe configuration, NPRACH format configuration and frequency-band placement mode.

To this end, the present disclosure further provides a method for predicting random access timing advance, the method comprising: receiving a narrowband physical random access channel (NPRACH) transmission group-one NPRACH transmission group is time A plurality of transmission units discontinuous in the domain, one transmission unit includes one or more consecutive NPRACH symbol groups in the time domain, and the phases between two adjacent transmission units are continuous or the phases are fixed-, Determine the phase deviation according to the time-frequency interval and / or frequency domain interval between multiple adjacent transmission unit pairs in the NPRACH transmission group, and / or according to the frequency domain interval between different symbol groups in the transmission unit (s) Determining phase deviation, timing advance (TA) according to phase deviation The transmission determining, and TA, NPRACH to adjust the time domain location for transmitting the transmission unit includes the step of displaying to the UE.

To this end, the present disclosure further provides user equipment for requesting random access, and the user equipment is configured to determine a time division duplex (TDD) uplink time domain resource, an uplink resource determination module, and TDD uplink time A transmission resource determination module, configured to determine a time domain resource used to transmit a narrowband physical random access channel (NPRACH), according to the domain resource, a transmission format determination module, configured to determine a time domain format for the NPRACH transmission group- The time domain format, one NPRACH transmission group includes at least two transmission units that are discontinuous in the time domain, and one transmission unit is configured to include one or more consecutive NPRACH symbol groups in the time domain-and transmits the determined NPRACH In the time domain resource used to do, the time domain It includes NPRACH transmission module configured to transmit the transmission NPRACH group of formats.

Compared to the prior art, the present disclosure has a variety of technical effects, including but not limited to the following technical effects: a random access process by designing a time domain format for NPRACH transmission according to the characteristics of a TDD uplink time domain resource May be applied to a TDD-based NB-IoT communication system, and accordingly, an existing NB-IoT system based on FDD may be applied to an operation mode of TDD. Thus, higher spectral resource utilization is achieved, and in a scenario in which multiple UEs are connected, system throughput and connection efficiency of the NB-IoT system are significantly improved.

Various embodiments of the present disclosure provide a more effective uplink control information transmission method and a random access method.

1 is a schematic diagram of a wireless communication system.
2 illustrates a base station in a wireless communication system according to various embodiments of the present disclosure.
3 illustrates a user equipment (UE) in a wireless communication system according to various embodiments of the present disclosure.
4 is a schematic diagram of a basic flow of a method for transmitting uplink control information (UCI) according to the present disclosure.
5 is a first schematic diagram of UCI transmission in a time division duplex (TDD) system.
6 is a second schematic diagram of UCI transmission in a TDD system.
7 is a third schematic diagram of UCI transmission in a TDD system.
8 is a schematic diagram of a method for indicating a frequency domain location for transmitting UCI.
9 is a schematic diagram of a detailed flow of a UCI transmission method according to an embodiment of the present disclosure.
10 is a schematic diagram of a basic flow of a UCI receiving method according to the present disclosure.
11 is a schematic diagram illustrating that a base station schedules multiple UEs.
12 is a schematic diagram illustrating that a base station schedules multiple downlink transmissions for one UE.
13 is a schematic diagram for transmitting UCI in a scenario where there is a conflict between a UCI and a physical uplink shared channel (PUSCH).
14 is a schematic diagram of the basic structure of a UCI transmission apparatus according to the present disclosure.
15 is a schematic diagram of the basic structure of a UCI receiving apparatus according to the present disclosure.
16 is a basic flowchart of signal transmission in a TDD system guardband operation mode or an in-band operation mode according to the present disclosure.
17 is a schematic diagram of uplink and downlink carriers in a TDD narrowband system.
18 is an exemplary flowchart for a UE to obtain a center frequency of an uplink carrier.
19 is a flowchart of a method for requesting random access according to the present disclosure.
20 is a flow diagram of a method for predicting random access timing advance (TA) in accordance with the present disclosure.
21 is a schematic diagram of a narrowband physical random access channel (NPRACH) transmission group according to the present disclosure.
22 is a schematic diagram of a first type of NPRACH transmission according to the present disclosure.
23 is a schematic diagram of a second type of NPRACH transmission according to the present disclosure.
24 is a schematic diagram of a third type of NPRACH transmission according to the present disclosure.
25 is a module diagram of a UE according to the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail. Examples of these embodiments are shown in the accompanying drawings, and the same or similar reference numbers throughout the drawings refer to the same or similar elements or elements having the same or similar functions. The embodiments described with reference to the accompanying drawings are illustrative, and used only to describe the present disclosure, and the present disclosure should not be regarded as being limited thereto.

It will be understood by those skilled in the art that singular forms may also include plural forms unless expressly stated otherwise. As used herein, the term “comprises / comprising” refers to the presence of features, integers, steps, actions, elements and / or components, but one or more other features, integers, steps, actions, elements, components, and / or It will also be understood that it does not exclude the presence or addition of combinations thereof. It will be appreciated that when an element is referred to as being “connected” or “coupled” to another element, there may be intervening elements that may be directly connected or coupled to the other element. Also, as used herein, "connection" or "coupling" may include wirelessly connected or coupled. As used herein, the term “and / or” includes any and all combinations of one or more related listed items.

Unless defined otherwise, one of ordinary skill in the art should understand that all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. . Also, terms such as commonly used dictionary-defined terms should be interpreted as having meanings consistent with meanings in the context of the prior art, and are not to be interpreted as ideal or excessively formal meanings unless explicitly defined herein. You have to understand.

As used herein, "terminal" and "terminal device" are devices having a radio signal receiver device which is a device having only a radio signal receiver without transmission capability, as well as a device having reception and transmission hardware capable of performing two-way communication over a bidirectional communication link. It will be understood by those skilled in the art that it includes an apparatus having hardware for receiving and transmitting phosphorus. Such devices may include cellular or other communication devices with a single line display or multi-line display or cellular or other communication devices without a multi-line display; Personal Communication Services (PCS), which may be a combination of voice, data processing, fax and / or data communication functions; A personal digital assistant (PDA), which may include a radio frequency (RF) receiver, pager, internet / intranet access, web browser, node pad, calendar, and / or Global Positioning System (GPS) receiver; It may include a conventional laptop and / or palmtop computer or other device, which may be a conventional laptop and / or palmtop computer or other device having and / or including an RF receiver. As used herein, "terminal", "terminal device" may be portable, transportable, vehicle (air, sea and / or land) installed, or may be adapted and / or configured to operate locally and / or It can operate in distributed form on Earth and / or other places in the universe. As used herein, “terminal” and “terminal device” may also be communication terminals, Internet terminals, music / video playback terminals. For example, this may include PDAs, mobile internet devices (MIDs) and / or mobile phones with music / video playback capabilities, or smart TVs, set-top boxes and other devices.

In a long term evolution (LTE) system, uplink control information (UCI) is transmitted at both ends of the system bandwidth. In this way, the LTE system not only obtains frequency hopping (FH) gain to provide decoding performance, but also provides uplink resources to provide resources that can be continuously allocated to a physical uplink shared channel (PUSCH). Fragmentation of them can be avoided efficiently. In the enhanced machine type communication (eMTC) system, the LTE system bandwidth is divided into a plurality of narrow bands, and each narrow band is composed of six physical resource blocks (PRBs) used for PUSCH transmission. In LTE system bandwidth, PUCCH (Physical Uplink Control Channel) carrying UCI indicates PRB location using Radio Resource Control (RRC) indicator, and frequency of UCI according to MTC physical downlink control channel (MPDCCH) and DCI indicator. Determine the location of the domain resources further. The 3rd Generation Partnership Project (3GPP) Rel-13 has a bandwidth of only 200 kHZ (i.e., one PRB) and a narrowband Internet of Things in which UCI is transmitted using narrowband physical uplink shared channel (NPUSCH) format 2. things, NB-IoT) system, time-frequency physical resources of NPUSCH format 2 are indicated by DCI, and candidate time-frequency locations are predefined in the standard.

In 3GPP Rel-15, since the NB-IoT system operating in the time division duplex (TDD) frequency band is standardized and the number of uplink slots is limited, when the rules of NPUSCH format 2 and FDD NB-IoT are continuously used, The uplink resource granularity is seriously destroyed, which seriously affects the actual uplink data rate of the system. Thus, the problem of how to effectively transmit UCI has not yet been solved, especially for narrowband systems operating in the TDD frequency band, for example, TDD NB-IoT systems.

In addition, since the NB-IoT system bandwidth is only 200 kHz, the uplink subframes of the anchor carrier are downlink common channels (for example, narrowband primary synchronization signal (NPSS), narrowband secondary synchronization signal) It is used by (narrowband secondary synchronization signal, NSSS) and narrowband physical broadcast channel (NPBCH), which makes uplink and downlink ratios uneven. Accordingly, it is necessary to define a more flexible multi-carrier operation mode in the TDD NB-IoT system in order to balance the use of uplink and downlink resources.

For a TDD NB-IoT system operating within an inband or guardband of an LTE system, in order to strictly align with the PRB resources of the LTE system while maintaining orthogonality with the LTE system, the TDD NB-IoT There should be a constant offset between the uplink and downlink center frequencies of the system. In addition, in the NB-IoT system, since the radio frequency precision of the base station cannot be achieved by the UE in the NB-IoT system, in order to satisfy the requirements of out-of-band leakage for the guardband operating mode, the NB-IoT UE is partially In guardbands, it is not possible to perform uplink transmission on some carrier frequencies. That is, since there are no uplink carriers corresponding to downlink carriers of some TDD NB-IoT systems, the base station needs to additionally configure uplink carriers corresponding to these downlink carriers.

Accordingly, the present disclosure provides a solution to the above-described carrier configuration problem.

Further, in 3GPP Rel-13, in the case of a standard NB-IoT system, the frequency-band distribution may be LTE in-band deployment, LTE guard-band deployment, or standalone deployment. In Rel-14, positioning, broadcast, multi-carrier or other enhancement technologies are integrated into 3GPP. Currently, the FDD system is integrated into a standard NB-IoT system, and the NB-IoT terminals are HD-FDD terminals. In order to better serve different applications in the Internet of Things (IoT) and meet different requirements, NB-IoT system normalization in the TDD frequency spectrum will be developed in 3GPP Rel-15.

The random access process is an important method of establishing a connection between a network side and a terminal side in a mobile communication system, and the performance of random access has a direct effect on the system's work efficiency. In an NB-IoT system based on FDD, in the frequency domain, a random access channel (NPRACH) is in the form of a single carrier with a subcarrier spacing of 3.75 kHz; In the time domain, NPRACH is a symbol group consisting of one cyclic prefix (CP) and five symbols, where one NPRACH is formed for every four symbols. However, since the symbol length corresponding to 3.75 kHz is 266.67us and the TDD system has a completely different frame structure from the FDD system, when the FDD-based NB-IoT system is deployed in the LTE band or LTE guard band, NPRACH transmission is TDD LTE It is necessary to maintain consistency with the uplink-downlink configuration of. Therefore, the existing NPRACH for FDD cannot be applied to the TDD system in terms of format, size, and transmission location.

In consideration of this, there is a need to provide a method and user equipment for requesting random access that can solve the aforementioned problems.

1 illustrates an exemplary wireless communication system 100 in accordance with embodiments of the present disclosure in which a UE detects indication information. The wireless communication system 100 includes one or more fixed infrastructure units for forming a distributed network in a geographic area. The infrastructure unit is an access point (AP), access terminal (AT), base station (BS), node B (Node-B), evolved node B (eNB), next generation node B (gNB) or other fields of the art. It may be referred to as a term used. As shown in FIG. 1, one or more infrastructure units 101 and 102 may include, for example, a plurality of mobile stations (MSs), user equipments (UEs), or terminal devices or users in a cell or cell sector. (103 and 104). In some systems, one or more BSs can be communicatively coupled to a controller forming an access network, and the controller can be communicatively coupled to one or more core networks. This disclosure does not limit wireless communication systems to specific types.

In the time domain and / or frequency domain, the infrastructure units 101 and 102 transmit downlink (DL) communication signals 112 and 113 to the UEs 103 and 104, respectively. UEs 103 and 104 communicate with one or more infrastructure units 101 and 102 via uplink (UL) communication signals 111 and 114, respectively. In one embodiment, the mobile communication system 100 is an orthogonal frequency division multiplexing (OFDM) / orthogonal frequency division multiple access (OFDMA) system including multiple base stations and multiple UEs. The multiple base stations include the base station 101 and the base station 102, and the multiple UEs include the UE 103 and the UE 104. The base station 101 communicates with the UE 103 through the uplink communication signal 111 and the downlink communication signal 112. When a base station has downlink packets to be transmitted to UEs, each UE is wireless in one downlink location (resource), for example, a physical downlink shared channel (PDSCH) or a narrow band downlink shared channel (NPDSCH). You will get a set of resources. When the UE needs to transmit packets to the base station via uplink, the UE obtains a grant from the base station, which grant includes a narrowband physical uplink shared channel (NPUSH) or physical that includes a set of uplink radio resources. Allocate an uplink shared channel (PUSCH). The UE acquires downlink or uplink scheduling information from a PDCCH, MPDCCH, or EPDCCH, or a NPDCCH specific to the UE. In the following description, these channels are integrated as PDSCH, PDCCH and PUSCH. Downlink or uplink scheduling information and other control information carried in a downlink control channel are referred to as downlink control information (DCI). 1 also shows different physical channels of the downlink 112 and the uplink 111. The downlink 112 is a PDCCH or EPDCCH or NPDCCH or MPDCCH 121, a PDSCH or NPDSCH 122, a physical control formation indicator channel (PCFICH) 123, and a physical multicast channel. , PMCH) 124, physical broadcast channel (PBCH) or NPBCH 125, physical hybrid automatic repeat request indicator channel (PHICH) 126 and primary synchronization signal (primary synchronization signal, PSS), secondary synchronization signal (secondary synchronization signal, SSS), or NPSS / NSSS (127). The downlink control channel 121 transmits a downlink control signal to the UE. The DCI 120 is carried in the downlink control channel 121. PDSCH 122 transmits data information to the UE. PCFICH 123 is used, for example, to transmit PDCCH decoding information that dynamically indicates the number of symbols used by PDCCH 121. The PMCH 124 carries broadcast and multicast information. The PBCH or NPBCH 125 carries a master information block (MIB), which is used for UE early detection and cell-wide coverage. PHICH carries hybrid automatic repeat request (HARQ) information, and HARQ information indicates whether the base station correctly receives the transmitted signal. The uplink 111 includes a physical uplink control channel (PUCCH) 131 carrying uplink control information (UCI) 130, a PUSCH 132 carrying uplink data information, and random access information. And a physical random access channel (PRACH) 133 that carries. In the NB-IoT system, there is no definition for NPUCCH, and NPUSCH format 2 is used to transmit UCI 130.

In one embodiment, the wireless communication network 100 includes a next-generation single carrier FDMA architecture or multi-carrier OFDMA structure used for adaptive modulation and coding (AMC) and uplink transmission on the downlink, Use OFDMA or multi-carrier architecture. FDMA-based single carrier structure includes Interleaved FDMA (IFDMA), Localized FDMA (LFDMA), IFDMA, or DFT-S-OFDM (DFT-Spread OFDM) of IFDMA. In addition, the FDMA-based single carrier architecture is a variety of enhanced non-orthogonal multi-access architecture (NOMA) of OFDMA system, for example, PDMA (Pattern division multiple access), SCMA (Sparse code multiple access) , Multi-user shared access (USA), LCRS Low code rate spreading Frequency domain spreading (FDS), Non-orthogonal coded multiple access (NCMA), Resource spreading multiple access (RSMA), Interleave-grid multiple access (IGMA), LDS -Low density spreading with signature vector extension (SVE), Low code rate and signature based shared access (LSSA), Non-orthogonal coded access (NOCA), Interleave division multiple access (IDMA), Repetition division multiple access (RDMA), GOCA (Group orthogonal coded access), WSMA (Welch-bound equality based spread MA).

In an OFDMA system, downlink or uplink radio resources, typically including a set of subcarriers on one or more OFDM symbols, are allocated to provide remote elements. Exemplary OFDMA protocols include the evolved LTE and IEEE 1003.16 standards developed from the 3GPP UMTS standard. The architecture also includes transmission techniques such as multi-carrier CDMA (MC-CDMA), multi-carrier direct sequence CDMA (MC-DS-CDMA), and orthogonal frequency and code division multiplexing for one division or this division transmission. (orthogonal frequency and code division multiplexing, OFCDM). Or, the OFDMA system may be based on simpler time division and / or frequency division multiplexing / multiple access techniques, or a combination of these techniques. In an alternative embodiment, the communication system may use other cellular communication protocols, including but not limited to TDMA or direct sequence CDMA.

In the FDD NB-IoT system, UCI is transmitted using NPUSCH format 2. For an uplink subcarrier gap of 3.75 kHZ, one UCI transmission occupies only one subcarrier and 8 ms; For the 15 kHz uplink subcarrier gap, one UCI transmission occupies only one subcarrier and 2 ms. In the case of NPUSCH format 2, the actual occupied carrier is indicated from a predefined table using DCI scheduling downlink NPDSCH. In order to allow enough time for a UE with low complexity to decode the NPDSCH, the feedback time of HARQ-ACK is 12 ms or more. The conventional downlink NPDSCH feedback mechanism used for FDD NB-IoT is difficult to transmit uplink data at high speed (eg, occupying 12 subcarriers).

2 illustrates a base station of a wireless communication system according to various embodiments of the present disclosure. The structure illustrated in FIG. 2 may be understood as the structure of BS 110 or 102. The term "-module", "-unit" or "-group" as used hereinafter may refer to a unit for processing at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software. You can.

Referring to FIG. 2, the BS may include a wireless communication interface 210, a backhaul communication interface 220, a storage unit 230 and a controller 240.

The wireless communication interface 210 performs a function of transmitting and receiving signals through a wireless channel. For example, the wireless communication interface 210 may perform a conversion function between the baseband signal and the bitstreams according to the physical layer standard of the system. For example, in data transmission, the wireless communication interface 210 generates complex symbols by encoding and modulating transmission bitstreams. In addition, upon receiving data, the wireless communication interface 210 demodulates and decodes the baseband signal to reconstruct received bitstreams.

In addition, the wireless communication interface 210 up-converts the baseband signal to a radio frequency (RF) band signal and transmits it through the antenna, and then downconverts the RF band signal received through the antenna to the baseband signal. To this end, the wireless communication interface 210 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter, and the like. Further, the wireless communication interface 210 may include a plurality of transmission / reception paths. In addition, the wireless communication interface 210 may include at least one antenna array composed of a plurality of antenna elements.

In terms of hardware, the wireless communication interface 210 may include a digital unit and an analog unit, and the analog unit may include a plurality of sub-units according to operating power and operating frequency. The digital unit may be implemented as at least one processor (eg, digital signal processor (DSP)).

The wireless communication interface 210 transmits and receives signals as described above. Accordingly, the wireless communication interface 210 may be referred to as a “wireless communication unit”, a “wireless communication module”, a “transmitter”, a “receiver”, or a “transceiver”. In addition, in the following description, transmission and reception performed through a wireless channel may be used to have a meaning including processing performed by the wireless communication interface 210 as described above.

The backhaul communication interface 220 provides an interface for performing communication with other nodes in the network. That is, the backhaul communication interface 220 converts the bitstreams transmitted from the BS to another node, for example, another access node, another BS, an upper node or a core network, into physical signals, and bites the physical signals received from the other nodes. Convert to streams. The backhaul communication interface 220 may be referred to as a “backhaul communication unit” or a “backhaul communication module”.

The storage unit 230 stores data such as basic programs, applications, and configuration information for operation of the BS. The storage unit 230 may include volatile memory, nonvolatile memory, or a combination of volatile memory and nonvolatile memory. In addition, the storage unit 230 provides stored data in response to a request from the controller 240.

The controller 240 controls the general operation of the BS. For example, the controller 240 transmits and receives signals through the wireless communication interface 210 or the backhaul communication interface 220. In addition, the controller 240 writes data to the storage unit 230 and reads the recorded data. The controller 240 may perform the functions of the protocol stack required in the communication standard. According to another implementation, a protocol stack may be included in the wireless communication interface 210. To this end, the controller 240 may include at least one processor. According to exemplary embodiments of the present disclosure, the controller 240 may control the base station to perform operations according to the exemplary embodiments of the present disclosure.

3 illustrates a UE in a wireless communication system according to various embodiments of the present disclosure. The structure illustrated in FIG. 3 may be understood as the structure of UEs 103 and 104. The term "-module", "-unit" or "-group" as used herein may refer to a unit that processes at least one function or operation, and may be implemented in hardware, software, or a combination of hardware and software. You can.

Referring to FIG. 3, the UE includes a communication interface 310, a storage unit 320 and a controller 330.

The communication interface 310 performs a function of transmitting / receiving signals through a wireless channel. For example, the communication interface 310 performs a conversion function between the baseband signal and the bitstreams according to the physical layer standard of the system. For example, in data transmission, communication interface 310 generates complex symbols by encoding and modulating transmission bitstreams. In addition, upon receiving data, the communication interface 310 reconstructs the received bitstreams by demodulating and decoding the baseband signal. In addition, the communication interface 310 up-converts the baseband signal to an RF band signal and transmits it through the antenna, and then downconverts the RF band signal received through the antenna to the baseband signal. For example, communication interface 310 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC.

Also, the communication interface 310 may include a plurality of transmission / reception paths. Further, the communication interface 310 may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the wireless communication interface 210 may include digital circuitry and analog circuitry (eg, radio frequency integrated circuit (RFIC)). The digital circuit and analog circuit may be implemented as one package. The digital circuit may be implemented as at least one processor (eg, DSP). The communication interface 310 may include a plurality of RF chains. The communication interface 310 may perform beamforming.

The communication interface 310 transmits and receives signals as described above. Accordingly, the communication interface 310 may be referred to as a "communication unit", a "communication module", a "transmitter", a "receiver" or a "transceiver". In addition, in the following description, transmission and reception performed through a wireless channel are used to have a meaning including processing performed by the communication interface 310 as described above.

The storage unit 320 stores data such as basic programs, applications, and configuration information for operation of the UE. The storage unit 320 may include volatile memory, nonvolatile memory, or a combination of volatile memory and nonvolatile memory. In addition, the storage unit 320 provides stored data in response to a request from the controller 330.

The controller 330 controls the general operation of the UE. For example, the controller 330 transmits and receives signals through the communication interface 310. In addition, the controller 330 writes data to the storage unit 320 and reads the recorded data. The controller 330 may perform functions of a protocol stack required in a communication standard. According to another implementation, a protocol stack may be included within the communication interface 310. To this end, the controller 330 may include at least one processor or microprocessor, or may perform part of the processor. Also, a part of the communication interface 310 or the controller 330 may be referred to as a communication processor (CP). According to exemplary embodiments of the present disclosure, the controller 330 may control the UE to perform operations according to exemplary embodiments of the present disclosure.

4 is a flowchart of a method for transmitting uplink control information according to the present disclosure.

Referring to FIG. 4, in step 401, the UE determines at least two carriers for uplink transmission in a cell currently connected by the UE, and determines carriers for UCI transmission from the determined at least two carriers.

In the method of the present disclosure, the cell connected by the UE includes at least two carriers for the UE to perform uplink transmission. This disclosure is particularly applicable to narrowband systems, in narrowband systems, the UE receives and transmits information on only one carrier at a time. Preferably, the UCI and uplink data of the UE may be transmitted on different carriers, that is, the carrier for the UE to transmit UCI and the uplink carrier corresponding to the downlink data are different.

In step 403, the UE determines the relative frequency domain position and time domain start position occupied by the UCI in the carrier for UCI transmission determined in step 401.

In step 405, the UE re-adjusts its center radio frequency to the center frequency of the carrier for UCI transmission, and transmits the UCI according to the relative frequency domain position and time domain start position occupied by the UCI.

In the case of the UE in the NB-IoT system, the UE only supports operating on one carrier at a time, and not simultaneously operating on two carriers. Meanwhile, as described above, since the downlink data channel of the UE and the UCI are transmitted through different carriers, before the UE transmits the UCI, the UE re-adjusts its central radio frequency to the center point of the carrier for UCI transmission. Then, you must send the UCI.

Until then, the entire flow of the UCI transmission method according to the present disclosure ends. Hereinafter, each processing step in the flow of the UCI transmission method will be described in detail.

First, the UCI may be transmitted through an uplink control channel (eg, PUCCH) or an uplink shared channel format 2 channel (eg, NPUSCH format 2 channel). The carrier in which the UCI is located is determined by step 401. The UCI includes at least one of the following information: HARQ-ACK information indicating a decoding state of a downlink data channel (ie, downlink shared channel), uplink scheduling request (SR) information, and periodic and / or Aperiodic channel state information (CSI).

In step 401, when determining at least two carriers for uplink transmission of the UE, several detailed approaches can be used as follows:

Approach 1: The UE may determine respective carriers used for uplink transmission of the UE according to signaling transmitted from the base station (eg, RRC signaling including system information (SIB), UE specific signaling, etc.). For example, the UE may acquire center frequencies of each carriers used for uplink transmission according to signaling and then determine corresponding carriers;

Approach 2: As a single carrier used for uplink transmission, a UE transmits an uplink carrier corresponding to an anchor carrier (a carrier through which a downlink synchronization channel is transmitted) or a random access channel (eg, NPRACH) is transmitted. It can be used, and then determines other carriers used for uplink transmission according to signaling transmitted from the base station or according to a predefined rule. Pre-defined rules can be defined on demand. For example, some carriers that are adjacent to the uplink carrier corresponding to the anchor carrier or adjacent to the carrier on which the random access channel is transmitted may be defined as these other carriers. In the case of a TDD system, the downlink carrier and the corresponding uplink carrier have the same center frequency, and there is no need to use additional signaling to indicate them; That is, in the TDD system, the downlink carrier position determined by the UE through cell discovery is the uplink carrier position, and the carrier transmitting the synchronization channel is the anchor carrier. In the case of the FDD system, after the UE determines the location of the downlink carrier, the base station configures an uplink carrier corresponding to the downlink carrier through RRC signaling. That is, the uplink carrier corresponding to the anchor carrier is indicated by RRC signaling.

In step 401, when determining a carrier for UCI transmission, the following methods can be used:

Approach a: The UE determines a carrier for UCI transmission according to the designated signaling transmitted from the base station. The designated signaling may be signaling indicating at least two carriers for uplink transmission for the UE in approach 1, that is, when the base station configures at least two carriers for uplink transmission of the UE through this signaling, The base station directly indicates the carrier for UCI transmission in this signaling; Or, the designated signaling may be signaling indicating other carriers for uplink transmission in approach 2, that is, when the base station configures other carriers for uplink transmission through this signaling, the base station makes UCI transmission in this signaling. For carriers directly. For example, preferably, the UE determines a carrier for UCI transmission according to RRC signaling, physical layer information, or MAC layer signaling. Specifically, the base station allocates different carriers for UCI transmission and uplink data of the UE through RRC signaling, and in this way, when the UE receives RRC signaling, it is possible to determine the carrier used for uplink transmission. In addition, it is also possible to determine the carrier on which UCI is transmitted.

Approach b: After the UE determines carriers for uplink transmission, the carrier for UCI transmission is determined according to the additionally transmitted signaling from the base station. That is, the base station configures multiple uplink carriers for the UE according to approach 1 or approach 2, after which the UE is configured by DCI or MAC signaling, or signaling such as UE specific RRC retransmitted by the base station In accordance with Approach 1 or Approach 2, it is determined which carrier to use to transmit UCI from a plurality of uplink carriers determined according to Approach 1.

Approach c: When determining carriers for uplink transmission of the UE using approach 2, the carrier for UCI transmission may be determined according to a predefined rule. For example, the rule is that the UCI is transmitted through a carrier other than the uplink carrier corresponding to the non-anchor carrier, or the carrier in which the NPRACH is located, or the UCI is transmitted through the uplink carrier corresponding to the PDCCH or PDSCH. Or, it is predefined that the UCI is not transmitted on the uplink carrier corresponding to the PDCCH or PDSCH.

5 is a schematic diagram of UCI transmission in a TDD system. When determining carriers, the UE can acquire two carriers that can be used for uplink transmission, eg, carrier 1 and carrier 2, through higher layer signaling (eg, SIB or UE specific RRC signaling). Alternatively, the UE may perform cell discovery to obtain the location of the downlink anchor carrier, and after the UE determines that the current system is a TDD system, the UE determines that the downlink anchor carrier is an uplink carrier (eg, FIG. 3). Carrier 1) directly, and then acquire the positions of other carriers (eg, carrier 2 in FIG. 3) according to higher layer signaling or according to a predefined rule, and UCI can determine these other carriers (eg For example, it is transmitted on the carrier 2) of FIG. 3. Assuming that both the downlink control channel PDCCH and the downlink data channel PDSCH scheduled by the PDCCH are transmitted on carrier 1, the UCI used for PDSCH feedback is transmitted on carrier 2. The UE decodes the downlink data channel and generates UCI according to the decoding result of the downlink data channel.

In FIG. 3, the relative frequency domain location and time domain start location for UCI transmission can be determined using conventional methods. For example, the time offset for the end position and / or frequency domain position of the PDSCH can be indicated by DCI. Specifically, a time offset and / or frequency domain location set may be configured or predefined by RRC, and DCI represents a value of one of these sets. Alternatively, a minimum time offset (eg, 12 ms or 6 ms) is predefined, and the time domain start position of the UCI is a position starting from the end position of the PDSCH and satisfying the minimum time offset. In addition, PUSCH used for uplink data transmission may be transmitted on carrier 1, which is different from carrier used for UCI transmission. In the case of the TDD system, when the UCI and PDSCH / PUSCH are in different carriers, when performing re-adjustment, sufficient time for the UE should be reserved (ie, the preliminary time for re-adjusting the center frequency in step 405 (eg For example, it should be noted that 1ms)).

Hereinafter, a method for determining the time domain start position occupied by the UCI in step 403 will be described in detail. As shown in FIG. 3, a conventional method may be used as a method of determining a time domain start position. However, in the TDD system, since uplink and downlink subframe configurations are different and time positions available for uplink transmission are not limited, when the conventional method of determining the time domain start position is used, the determined time domain start position May belong to downlink transmission time. Therefore, in the TDD system provided by the present disclosure, when determining the time domain start position occupied by the UCI, the first effective uplink transmission position starting from the end position of the downlink data channel and satisfying the specified time offset, It is determined as the time domain starting position. The specified time offset may be a preset minimum time offset, or the specified time offset may be a time offset determined according to signaling transmitted from the base station (eg, via RRC or MAC or DCI). In the NB-IoT FDD system, the time offset is an absolute value (eg {13, 15, 17, 18} ms). However, in a TDD system, effective uplink subframes may be discontinuous due to different uplink and downlink configurations. To better utilize the characteristics of the TDD system, and to ensure the time for decoding the PDSCH, the time offset of the UCI can be defined as the x th uplink time unit satisfying the minimum time offset of 12 ms, for example X May be a value of one of the sets {0,1,2,4}, or may be indicated by a downlink DCI. One time unit may be a transmission length of a slot, a subframe, a symbol, and one resource unit (RU), or may be an absolute time (for example, 1 ms). This set may be preset in the protocol, or may be configured through RRC. One effective uplink location may be a time length of one UCI transmission, for example, one subframe or one slot or two slots. For example, in the case of a subcarrier gap of 15 kHz, the time length of one UCI transmission is 1 ms, and in the case of a subcarrier gap of 3.75 kHz, the time length of one UCI transmission is 4 ms. Specifically, one UCI transmission may consist of 8 symbols carrying UCI data and 7 demodulation reference signals (DMRS) used for UCI detection. For example, the first, second, sixth, and seventh symbols of the slot are symbols that carry UCI data, and the third, fourth, and fifth symbols are symbols that carry DMRS, or the first, first, The second and third symbols are symbols that carry DMRS, and the fourth, fifth, sixth, and seventh symbols are symbols that carry UCI data. One UCI transmission is performed over two slots, and the UE may repeatedly transmit UCI multiple times according to a configuration configured by a base station.

In the method for determining the time domain start position of the above-described TDD system, the difference from the conventional method is the first effective uplink transmission position satisfying the specified time offset. Therefore, hereinafter, the effective uplink transmission location will be described in detail.

6 is a schematic diagram of UCI transmission in a TDD system, where D represents a downlink subframe determined according to the current TDD uplink and downlink subframe configuration, and the downlink subframe is reserved for downlink transmission; U indicates an uplink subframe determined according to the current TDD uplink and downlink subframe configuration, and the uplink subframe is reserved for uplink transmission; S represents a special subframe. As shown in FIG. 4, an effective uplink transmission location is an uplink subframe determined according to the current TDD uplink and downlink subframe configuration. That is, the UE determines the end position of the downlink data channel transmission determined according to the uplink and downlink subframe configuration and the time domain start position of resources occupied by the UCI according to the uplink subframe. Specifically, the UE determines the uplink subframe position according to the uplink and downlink subframes, and starts to transmit UCI in the uplink subframe satisfying the specified time offset.

As illustrated in FIG. 6, when the minimum time offset between the PDSCH and the UCI is 4 time units, the PDSCH is terminated in the first uplink subframe that can be used for UCI transmission and can satisfy at least 4 time units. It is after six time units. One time unit may be the transmission length of one slot, one subframe, one symbol, one resource unit (RU), or it may be an absolute value (eg 1 ms). In another example, when DCI represents four uplink time units, the time offset between PDSCH and UCI is the minimum time offset plus four uplink time units. Specifically, for example, when the minimum time offset is 12 ms, the uplink subframe for UCI transmission is the fourth uplink time unit 12 ms after the PDSCH. Since the uplink time units may be discontinuous, the absolute time may be greater than 12 ms + 4 ms (when one uplink time unit is 1 ms).

7 is another schematic diagram of UCI transmission in a TDD system, in which an uplink pilot slot (UpPTS) of a special subframe can be used as an effective uplink transmission position, and the effective uplink transmission position is the following approach It can be determined by:

In approach 1, both the uplink subframe U determined in accordance with the current uplink and downlink subframe configuration and the UpPTS in the special subframe can be used as an effective uplink transmission location. Specifically, the UE determines the uplink subframe position according to the uplink and downlink subframe configuration, and starts to transmit UCI in the first uplink subframe satisfying the minimum time offset or in the UpPTS of the special subframe. . For example, the minimum time offset between the PDSCH and the UCI is 4 time units, and the UpPTS of the first uplink subframe or special subframe that can be used for UCI transmission after the minimum time unit after the PDSCH is 5 after the PDSCH. UpPTS after one time unit, in this case, uplink control information 1 is a subsequent uplink indicator that is transmitted once (and retransmitted) once in the UpPTS.

In addition, the number of symbols in the UpPTS is configured according to special subframe configuration information, and in some configurations for the LTE special subframe, there is only one symbol used for SRS (Sounding Reference Signal) transmission in UpPTS, or two or There are only three symbols. In this case, this is not good for UCI coding, on the other hand, this can cause problems for the base station to configure the number of repetitions of UCI semi-statically. Thus, in Approach 2, when the threshold value can be preset and the number of symbols included in the special subframe is greater than the preset threshold value (for example, there are 5 or 6 symbols in the UpPTS), the special subframe UpPTS and uplink subframes can be used as effective uplink transmission positions, and when the number of symbols included in a special subframe is not greater than a preset threshold, only uplink subframes can be used as effective uplink transmission positions. . Specifically, regardless of the number of symbols in the UpPTS, the UpPTS may be defined as not used for uplink transmission.

Or in approach 3, whether the UpPTS of the special subframe can be used as the uplink transmission location is determined according to the special subframe configuration currently used. Preferably, the UpPTS corresponding to certain special subframe configurations can be preset or configured by the base station so that it can be used as an effective uplink transmission location. For example, in the detailed standard, under some special subframe configurations (eg, special subframe configurations 5 to 9), UpPTS can be used as an effective uplink transmission location, can be used for UCI transmission, and some other Under special subframe configurations (eg, special subframe configurations 0 to 4), UpPTS cannot be used as an effective uplink transmission location and can be defined as not being used for UCI transmission.

Or, in approach 4, the effective uplink transmission location may be determined based on a preset threshold (or specific special subframe configuration) combined with a specific uplink and downlink configuration. Specifically, under a specific uplink and downlink configuration, and under a situation in which the number of symbols included in the UpPTS is greater than a preset threshold (or a specific special subframe configuration), both UpPTS and uplink subframes are uplink transmission locations Field, otherwise, only uplink subframes may be used as the uplink transmission location. For example, UpPTS can be used for UCI transmission only when the number of uplink subframes is insufficient. For example, in LTE uplink and downlink configurations 2 and 4, there is only one uplink subframe and one special subframe every 10 ms or 5 ms. In this case, one UCI transmission occupies a total of 5 (or 6) + 14 = 19 (or 20) symbols, one UpPTS and one uplink subframe used for one UCI transmission. To improve coverage, retransmission based on this can be performed.

Or, in approach 5, if there are two consecutive uplink subframes or an even number of consecutive uplink subframes, only the uplink subframe U is uplink transmission location for transmitting UCI regardless of the number of symbols in the UpPTS. Can be used as For example, since the uplink control information 2 of FIG. 5 is transmitted only in two consecutive uplink subframes, integrity of UCI transmission can be guaranteed. For example, in the FDD NB-IoT system, the length of one RU in PUSCH format 2 with a subcarrier gap of 15 kHz is 2 ms. In this case, if the UCI needs to be repeated, it will be transmitted in the next two consecutive uplink subframes, and there will be no situation where only one uplink subframe is left. In this way, it becomes convenient for the base station to perform scheduling. When there are no two or even consecutive uplink subframes, the uplink transmission location may be determined according to approach 2 or approach 3. Specifically, in the case of a 3.75 kHz subcarrier gap, the length of one slot is 2 ms, and thus, in some uplink / downlink configurations, there may be three uplink subframes (that is, 3 ms), in this case In, the UE can transmit only one slot (i.e., 2 ms), and the third slot is idle and does not perform transmission. The next slot is transmitted next when there is a continuous 2 ms uplink position.

Alternatively, the base station may directly configure whether UpPTS of a special subframe can be used for UCI transmission. Alternatively, the base station may configure an effective uplink transmission location in a bitmap manner, and when a special subframe is configured as an effective uplink transmission location, UpPTS of the special subframe may be used for UCI transmission, and the special subframe. When configured as this invalid uplink transmission location, UCI can be transmitted only in the uplink subframe, and cannot be transmitted in the UpPTS of the special subframe.

The above approaches for indicating UCI scheduling delay are also applicable for indicating PDSCH and PUSCH. Specifically, the end position of the PDCCH and the start position of the PDSCH or PUSCH scheduled by the PDCCH are first subframes that can be used for uplink or downlink transmission after a scheduling delay indicated by DCI.

Hereinafter, some methods for determining the relative frequency domain position occupied by the UCI in step 403 will be described.

8 is a schematic diagram of a method for indicating a frequency domain location for transmitting UCI information. After the UE determines the carrier for UCI transmission, the UE can divide several subcarriers in the carrier into different frequency domain resource sets. As shown in FIG. 8, 12 subcarriers are divided into 4 frequency domain resource sets, and the base station can configure one of the 4 frequency domain resource sets for the UE through RRC signaling or MAC signaling. Thereafter, the base station can dynamically indicate a specific carrier from a set configured through DCI indicating PDSCH information. For example, in DCI, 2 bits are used to indicate position 1 from 3 positions, after which the UE transmits UCI in subcarrier 1 of the carrier for UCI transmission. Similarly, 12 subcarriers can be divided into 3 or 2 frequency domain resource sets, and there are 4 or 6 subcarriers in each frequency domain resource set. In another example, the base station may configure the starting position of the subcarrier and then indicate the offset from the starting position in DCI. For example, 2 bits can be used to indicate 4 offsets of {0, 1, 2, 3}. Different UEs may obtain a starting subcarrier location or frequency domain resource set used for UCI transmission according to UE specific RRC or MAC signaling. From the base station point of view, the base station can configure different frequency domain locations for UEs having different repetitions, and in this way, it becomes easier for the base station to schedule resources.

Specifically, the time domain resource location and the frequency domain resource location may be indicated together in DCI.

9 is a detailed flowchart of a method for transmitting uplink control information according to an embodiment of the present disclosure.

Referring to FIG. 9, in step 901, the UE acquires configuration information of a carrier for UCI transmission from a base station.

In step 903, the UE obtains a frequency domain set or frequency domain start position for UCI transmission from an RRC message or MAC information.

In step 905, the UE generates UCI information and determines a time-frequency resource location for UCI transmission according to a corresponding downlink data channel or a control channel and an uplink subframe used for UCI transmission.

In step 704, the UE transmits UCI information for UCI time-frequency resource location.

Specifically, a carrier used to transmit HARQ-ACK feedback information of MSG4 and / or a set of frequency domain resources within the carrier may be broadcast in System Information (SIB). Specifically, one carrier and / or one set of frequency domain resources within the carrier can be configured for each level of coverage. In another example, HARQ-ACK feedback information of MSG4 is transmitted on a carrier in which NPRACH of a corresponding coverage level is located. In a TDD system, this may be transmitted in an uplink subframe in which a carrier for MSG4 transmission is located. A carrier for transmitting HARQ-ACK information of a downlink data channel after MSG4 and / or a set of frequency domain resources in the carrier may be configured through UE-specific RRC or rewritten by MAC signaling. When the carrier for the UCI is not configured, basically, the UCI is transmitted on the corresponding uplink carrier. In other words, transmission on a non-anchor carrier or UCI specific carrier can be enabled or disabled through the configuration.

What has been described above is a detailed implementation of the UCI transmission method according to the present disclosure. The present disclosure further provides a method for receiving UCI, which corresponds to a transmission method.

Referring to FIG. 10, in step 1001, the base station determines at least two carriers for uplink transmission allocated to the UE in the cell currently connected by the UE, and transmits UCI of the UE from at least two carriers for uplink transmission Determine a carrier for;

In step 1003, the base station determines a relative frequency domain location and a time domain start location occupied by the UCI on the carrier determined for UCI transmission;

In step 1005, the base station receives the UCI in the carrier for UCI transmission of the UE according to the relative frequency domain location and time domain start location occupied by the UCI.

11 is a schematic diagram illustrating that a base station schedules UCIs of multiple UEs. 11, the carrier for UCI transmission may be configured by cell specific parameters or user specific parameters. From a base station perspective, multiple users' UCIs can be transmitted on the same carrier. In addition, with the help of TDD uplink and downlink subframes, it is very easy to align UCI transmissions. Specifically, as shown in FIG. 11, PDSCH 1 and PDCCH 1 of UE1 are transmitted on carrier 1, PDSCH 2 and PDCCH 2 of UE2 are transmitted on carrier 3, but the base station is UE1 and UE2 for carrier 2 Configures the UCI. In addition, it is easy to transmit UCIs of two UEs in the same subframe according to the offset of the time scheduling and the offset of the frequency scheduling. In this way, to improve spectral efficiency, segmentation of resources caused by UCI transmission can be avoided to the maximum.

12 is a schematic diagram illustrating a base station scheduling multiple downlink transmissions for a UE. 12, the UE supports two HARQ procedures, that is, the UE can transmit the second HARQ procedure even when the first HARQ procedure is not completed. Specifically, PDCCH1 schedules PDSCH1 and represents UCI time offset 1; PDCCH 2 schedules PDSCH2 and represents UCI time offset 2. By adjusting the UCI time offset, two UCIs can be transmitted in the same subframe. In this situation, they may be transmitted through HARQ bundling, that is, to obtain a bundling result, perform a “logical sum (or)” operation on two HARQ situations, and then transmit the bundling result. In another example, as shown in FIG. 12, HARQ procedures may be transmitted in different frequency domain resources to reduce PAPR, and two frequency domain resources for UCI transmission may occupy two adjacent subcarriers. have. The base station can guarantee transmission by scheduling.

In addition, considering the situation in which the UCI and the PUSCH may collide, the UCI may be transmitted through the PUSCH by piggyback. For example, as in LTE, some symbols close to DMRS are transmitted. Alternatively, the UCI may be transmitted through one subcarrier of resources through which the PUSCH is transmitted. The situation in which the UCI and PUSCH can collide may be a complete collision (including a situation in which their transmission times are the same or one of the transmission times is greater than another) or a partial collision (part of which collisions). As illustrated in FIG. 13, when the UCI transmission and the PUSCH collide, the UCI may be transmitted in a subcarrier location indicated by the base station on the carrier 1 on which the PUSCH is transmitted, and the PUSCH punctures resources occupied by the UCI Can be processed (i.e., performs rate matching according to the originally scheduled resources, but does not perform transmission on resources occupied by UCI), or performs rate matching (i.e., resources occupied by UCI) You can perform rate matching following restriction). In the case of DMRS, it may continue to use PUSCH or perform puncture. From the UE perspective, DMRS for PUSCH decoding may be used for UCI decoding. In another example, a MAC control element or MAC header can be defined as part of the data channel to be transmitted. In the case of partial collision, the collision portion can be processed as above, the non-conflict portion is transmitted normally, or the UCI or PUSCH of the collision portion is dropped (i.e., not transmitted). The method can be configured by the base station or predefined.

The present disclosure further provides an apparatus for transmitting UCI, which may implement the UCI transmission method in FIG. 14. 14 is a schematic diagram of the basic structure of a transmitting device. As shown in FIG. 14, the transmission apparatus includes a carrier determination unit 1410, a frequency domain and time domain determination unit 1020, and a transmission unit 1430.

The carrier determination unit 1410 is configured to determine at least two carriers for uplink transmission in the currently connected cell, and determine a carrier for UCI transmission from at least two carriers for uplink transmission. The UE's UCI and uplink data can be transmitted on different carriers. The frequency domain and time domain determination unit 1420 is configured to be used by the UE to determine the relative frequency domain location and time domain start location occupied by the UCI from the carrier determined for UCI transmission. The transmitting unit 1430 readjusts the center radio frequency of the UE to the center frequency of the carrier for UCI transmission, and transmits the UCI according to the relative frequency domain position and time domain start position occupied by the UCI; The transmitting unit 1430 transmits information on one carrier at a time.

The present disclosure further provides a UCI receiving device, which can be used to implement the aforementioned UCI receiving method. 15 is a schematic diagram of the basic structure of this receiving apparatus. As shown in Fig. 15, the receiving apparatus includes a carrier determining unit 1510, a frequency domain and time domain determining unit 1520, and a receiving unit 1530.

The carrier determination unit 1510 determines at least two carriers for uplink transmission assigned to the UE in the cell currently connected by the UE, and determines a carrier for the UE to transmit UCI from at least two carriers for uplink transmission. It is configured to. The UE's UCI and uplink data are transmitted on different carriers. The frequency domain and time domain determination unit 1520 is configured to determine the relative frequency domain and time domain start position occupied by the UCI on the carrier determined to transmit the UCI. The receiving unit 1530 is configured to receive UCI in the carrier used by the UE to transmit the UCI according to the relative frequency domain location occupied by the UCI and the time domain starting location; The UE transmits information on one carrier at a time.

The NB-IoT system in the TDD frequency band may have three operation modes. The first operation mode is a separate operation mode independent of the conventional network (ie, a standalone operation mode); The second mode of operation is to operate in the guardband of the LTE system (ie, guardband mode of operation); In addition, the third mode of operation is to operate in any resource block of the LTE carrier (ie, operate in-band of the LTE system) (ie, in-band mode of operation). Since the channel raster for the NB-IoT UE to perform cell search is 100 kHz, when the NB-IoT operates in the guard band of the LTE system, the channel raster of the anchor carrier (carrier transmitting the synchronization channel) must satisfy 100 kHz. .

In the NB-IoT system, for LTE in-band operation mode and guard-band operation mode, +/- 7.5 kHz or + / from a 100 kHz channel raster to enable a UE with low complexity to provide more flexible operation in an operating environment. -A frequency offset of 2.5 kHz may be allowed. Assuming that the LTE center frequency satisfies the channel raster of 100 kHz, Table 1 shows NB-IoT guardband operating modes corresponding to different LTE system bandwidths. As shown in Table 1, this is the anchor carrier frequency in the NB-IoT system (from which the offset between the frequency used as the anchor carrier and the LTE center frequency is known), the distance from the LTE carrier, and one It includes the number of anchor carriers that can be used as non-anchor carriers in the guardband and the number of effective uplink carriers in each guardband.

To more effectively reduce out-of-band leakage, it is desirable to select a frequency / carrier that is closest to LTE and meets the channel raster requirements, and a frequency / carrier farther from LTE as a non-anchor carrier. As shown in Table 1, for an LTE system with a bandwidth of 5 MHz, its anchor carrier can be composed of Fc + 2392.5 or Fc-2392.5 kHz, where Fc is as close to LTE as possible, and channel raster requirements It is the center frequency of the LTE system, to ensure that it meets. Specifically, the anchor carrier has a distance of 45 kHz, that is, three subcarriers, from the LTE edge. In this way, interference between OFDM carriers in the LTE system can be effectively avoided. Likewise, a system bandwidth of 15 MHz must reserve the frequency widths of the three subcarriers to place the anchor carrier. For 10MHz and 20MHz LTE systems, the first PRB outside the system bandwidth can meet channel raster requirements, so the first PRB outside the system bandwidth can be used as an anchor carrier. In addition to the frequencies in Table 1 that satisfy the anchor carrier channel raster requirements, there are many others. However, since the frequency spectra of Table 1 are mostly used, non-anchor carriers capable of placing them are most used.

In addition, Table 1 shows the number of effective uplink carriers on LTE system guardbands corresponding to different LTE system bandwidths. When comparing the number of downlink carriers that can be used for operation, since the out-of-band leakage of the UE cannot achieve accuracy as in the base station, avoiding interference with other systems by satisfying the out-of-band leakage requirements of the LTE system For this, the outermost carrier counted from the LTE center frequency cannot be used to perform uplink transmission for the UE. Therefore, when the outermost carrier is used, an uplink carrier of a different frequency must be configured and paired.

[Table 1]

In practice, in the case of TDD NB-IoT systems as well as other TDD narrowband systems, when they are deployed, the narrowband system can operate in the guardband of the wideband system (i.e., guardband operating mode) or narrowband The system can operate within the system bandwidth of the broadband system (ie, in-band operating mode). The present disclosure provides a signal transmission method, which is used to accurately transmit signals by determining a center frequency of a downlink carrier or an uplink carrier in a guardband operation mode or an inband operation mode of a TDD narrowband system.

16 is a basic flow chart of a method for transmitting signals in a guardband operation mode or an in-band operation mode of a TDD system.

Referring to FIG. 16, in step 1601, the UE acquires a first carrier in a TDD narrowband system, where the first carrier is in a guardband or inband of the TDD broadband system.

The first carrier may be an uplink carrier or a downlink carrier. If the first carrier is an uplink carrier, the second carrier is a downlink carrier corresponding to the uplink carrier; In addition, when the first carrier is a downlink carrier, the second carrier is an uplink carrier corresponding to the downlink carrier.

In step 1603, the UE determines the indication information of the second carrier corresponding to the first carrier obtained in step 1601, and determines the offset between the first carrier and the second carrier in the TDD narrowband system according to the indication information The center frequency of the second carrier corresponding to the first carrier obtained in step 1601 is calculated according to this offset.

Determining the indication information of the second carrier corresponding to the first carrier obtained in step 1601, when the first carrier obtained in step 1601 is an uplink carrier, the downlink corresponding to the uplink carrier obtained in step 1601 Determine the indication information of the carrier; When the first carrier obtained in step 1601 is a downlink carrier, it means determining the indication information of the uplink carrier corresponding to the downlink carrier obtained in step 1601. Similarly, calculating the center frequency of the second carrier corresponding to the first carrier obtained in step 1601 according to the offset means, when the first carrier obtained in step 1601 is an uplink carrier, the uplink obtained in step 1601 Determine a center frequency of a downlink carrier corresponding to the carrier; When the first carrier obtained in step 1601 is a downlink carrier, it means determining the center frequency of the uplink carrier corresponding to the downlink carrier obtained in step 1601. The offset between the first carrier and the second carrier is an offset between the uplink carrier / downlink carrier and the downlink carrier / uplink carrier.

In step 1605, the UE receives or transmits signals according to the center frequency of the second carrier determined in step 1603.

When the first carrier is a downlink carrier in step 1601, the downlink carrier may be an anchor carrier or a non-anchor carrier.

Hereinafter, a description will be given of a situation in which the one obtained in step 1601 is a downlink carrier.

When the downlink carrier is an anchor carrier in step 1601, in the case of a UE that connects / camps to the first cell, the UE first performs a cell search in step 1601 to obtain a center frequency of the downlink anchor carrier A; Then, in step 1603, the UE acquires the indication information of the uplink carrier corresponding to the downlink anchor carrier A, and finally determines the center frequency of the uplink carrier B corresponding to the downlink anchor carrier. Alternatively, if the downlink carrier is a non-anchor carrier in step 1601, the same procedures may be applied, which will not be described in detail here.

Specifically, the UE acquires the indication information through higher layer signaling (eg, master information block (MIB) or system information (SIB) or other RRC messages), and then downlink carrier The center frequency of the uplink carrier B corresponding to A may be determined. Preferably, the indication information of the uplink carrier may be one of the following information: the absolute value of the center frequency of the uplink carrier, location information for the TDD broadband system, and CRS sequence information. Specifically, the offset from the center frequency of the downlink carrier may be in the direction of the frequency offset between the uplink and downlink carriers, or whether the uplink carrier is at a high frequency or a low frequency of the LTE system (left or right). Whether or not; In the TDD broadband system, information of uplink resources occupied by uplink carrier B may be the location (index) of the PRB for the LTE system; Location information of an uplink carrier; And the information of the relative position in the TDD broadband system may be a relative position with respect to the center frequency of LTE, or may be a distance from the edge of the LTE system, or an n-th carrier capable of operating in a guard band.

In addition, in step 1601, the method of determining that the TDD narrowband system is located in the guardband or in-band of the TDD wideband system, the UE performs cell search to acquire a downlink carrier, and uses the next channel (s) or information. It may be determined that the downlink carrier is in-band of the wideband system or guardband of the wideband system: synchronization signal, MIB, SIB, UE specific RRC signaling, physical layer indication information, and MAC layer indication information.

Hereinafter, the detailed processing of step 1603 will be described. As an example, the TDD narrowband system is a TDD NB-IoT system, and the TDD wideband system is a TDD LTE system.

In step 1603, the offset between the uplink frequency and the downlink frequency in the TDD NB-IoT system needs to be determined according to the obtained indication information. Hereinafter, the reason why an offset exists between uplink and downlink carriers in a TDD NB-IoT system will be described first.

에서 시작하여, k=0을 스킵하고,

까지 계속된다. 그러나, 상향링크 방향의 경우, LTE 시스템은

내지

의 모든 서브캐리어들을 점유하며, 여기서

는 하향링크 PRB들의 개수이고,

는 상향링크 PRB들의 개수이고,

는 하나의 PRB 내의 서브캐리어들의 개수이고, k는 OFDM 또는 SC-FDMA 시스템에서의 주파수 도메인의 인덱스이다(자세한 정보는 TS 36.211을 참조). 인밴드 동작 모드 및 가드밴드 동작 모드를 갖는 NB-IoT 시스템의 경우, LTE 시스템의 대역폭의 일부(예를 들어, 하나의 PRB의 대역폭)만이 점유되어, LTE 시스템과의 간섭을 방지하며, NB-IoT 시스템은 PRB 단위로 카운트되는 하향링크 및 상향링크 주파수 도메인 리소스들을 점유해야 한다. LTE 시스템에서는 상향링크 및 하향링크 PRB들이 다르게 분할되기 때문에, 인밴드 동작 모드와 가드밴드 동작 모드를 갖는 TDD NB-IoT 시스템에서는, 한 쌍의 상향링크 및 하향링크 중심 주파수들 사이에 절반 서브캐리어 대역폭의 주파수 오프셋이 존재하게 된다. 예를 들어, 도 17의 협대역 시스템에서 사용되는 캐리어 1 및 캐리어 2에 의해 도시된 바와 같이, TDD NB-IoT 시스템에서 상향링크에 의해 실제 점유되는 주파수와 하향링크에 의해 실제 점유되는 주파수 사이에 +/- 7.5kHz의 주파수 오프셋이 존재한다. 특정 시스템(예를 들면, NB-IoT 및 LTE 시스템)의 경우, 상향링크 및 하향링크 캐리어 오프셋의 절대값은 정해져 있으며(예를 들면, LTE 시스템의 인밴드 또는 가드밴드에 배치된 NB-IoT 시스템의 경우, 상향링크 및 하향링크 캐리어 오프셋의 절대값은 7.5kHz임), UE는 시스템 파라미터들에 따라 이것을 계산할 수 있거나, 또는 절대값이 프로토콜에서 정의될 수 있으며, 시그널링은 왼쪽 또는 오른쪽으로의(양의 부호 또는 음의 부호) 오프셋을 구성한다.In the LTE system, when splitting PRBs between downlink carriers, the direct subcarrier (DC) does not belong to the PRBs, and in the uplink direction, DC is in the central subcarrier, so DC is PRB Belongs to the field. Thus, in LTE systems, the uplink SC-FDMA and downlink OFDMA baseband signal representations are the same as the frequency domain (phase) offset of 7.5 kHz. As shown in FIG. 17, in the LTE system, subcarriers occupied by downlink are low frequency.

Starting at, skip k = 0,

It continues until. However, in the uplink direction, the LTE system

To

Occupies all subcarriers of, where

Is the number of downlink PRBs,

Is the number of uplink PRBs,

Is a number of subcarriers in one PRB, and k is an index of a frequency domain in an OFDM or SC-FDMA system (see TS 36.211 for more information). In the case of an NB-IoT system having an in-band operation mode and a guard-band operation mode, only a part of the bandwidth of the LTE system (eg, bandwidth of one PRB) is occupied, preventing interference with the LTE system, and NB- The IoT system must occupy downlink and uplink frequency domain resources counted in PRB units. In the LTE system, since the uplink and downlink PRBs are divided differently, in a TDD NB-IoT system having an in-band operation mode and a guard-band operation mode, half a subcarrier bandwidth between a pair of uplink and downlink center frequencies There is a frequency offset of. For example, as shown by carrier 1 and carrier 2 used in the narrow-band system of FIG. 17, between the frequency actually occupied by the uplink and the frequency occupied by the downlink in the TDD NB-IoT system. There is a frequency offset of +/- 7.5 kHz. For certain systems (eg, NB-IoT and LTE systems), the absolute values of the uplink and downlink carrier offsets are fixed (eg, NB-IoT systems arranged in the in-band or guardband of the LTE system). In the case of, the absolute value of the uplink and downlink carrier offset is 7.5 kHz), the UE can calculate this according to the system parameters, or the absolute value can be defined in the protocol, signaling is left or right ( (Positive sign or negative sign) offset.

In the case of a TDD NB-IoT system operating in the in-band or guardband of the LTE TDD system, based on the offset between the center frequencies of a pair of uplink and downlink carriers in the NB-IoT system, the uplink of the LTE system In order to avoid interference with link and downlink transmission, in this disclosure, the UE acquires indication information in step 1603, and uses this indication information to calculate an offset between center frequencies of uplink and downlink carriers, Based on the center frequency of the downlink carrier determined in step 1601, combined with the offset between the center frequencies of the uplink and downlink carriers, the center frequency of the uplink carrier corresponding to the downlink carrier is accurately calculated. For in-band and guard-band operating modes, the base station may deliver indication information through an RRC message (including system information such as MIB, SIB, or UE-specific message), and this indication information is uplinked in the NB-IoT system It is used to calculate the offset between the link and downlink carriers.

18 is an exemplary flowchart of a UE obtaining a center frequency of an uplink carrier.

Referring to FIG. 18, in step 1801, the UE determines an operation mode of the TDD NB-IoT cell. In step 1803, the UE determines whether the operation mode is an in-band operation mode or a guardband operation mode, and if the operation mode is none of them, performs step 1805; If the operation mode is one of these, step 1807 is performed. In step 1805, when the operation mode of the TDD NB-IoT cell is a standalone operation mode, the UE determines that the center frequency of the uplink carrier is the center frequency of the downlink carrier corresponding to the uplink carrier.

In step 1807, when the operation mode is an in-band operation mode or a guardband operation mode, the UE acquires the indication information of the uplink carrier corresponding to the downlink carrier, and according to the indication information, the uplink in the NB-IoT system And determining the offset between the downlink carriers, and further determining that the center frequency of the uplink carrier is the offset of the center frequency of the downlink carrier corresponding to the uplink carrier.

The processing in step 1807 is the same as the processing in step 1603. In step 1807, the offset between the uplink and downlink carriers is determined according to the absolute value of the offset between the uplink and downlink carriers and the offset direction (ie, a negative or positive sign of the offset). The absolute value of the offset is fixed, equal to half the carrier width of the NB-IoT system. Therefore, the uplink carrier indication information is mainly used to determine the offset direction of frequencies between the uplink carrier and the downlink carrier. Specifically, the uplink carrier indication information includes CRS sequence information, PRB indexes occupied by the uplink carrier, a frequency offset direction between uplink and downlink carriers, a relative position with respect to the LTE center frequency, and an edge of the LTE system. At least one of a relative position, a n-th carrier capable of operating in a guard band, PRB positions (indexes) in LTE, and whether an uplink carrier is at a high frequency or a low frequency (left or right) of the LTE system. It can be information. Here, the offset between uplink and downlink carriers determined according to the indication information may be positive, negative, or zero. If the offset frequency is 0, it means that the operation mode is a standalone operation mode.

In the indication information, the frequency offset direction between uplink and downlink carriers indicates whether the offset between uplink and downlink carriers is positive or negative, and this is usually indicated using 1 bit. The fact that the uplink carrier is located in the high frequency or low frequency (left or right) of the LTE system means that in the guard band operation mode, the uplink carrier is located in the high frequency or low frequency (left or right) guard band of the LTE system. ; In the in-band operation mode, it means that the uplink carrier is located in the high frequency or low frequency (left or right) portion of the LTE system. In practice, the parameter is also a positive or negative sign indicating the offset between the uplink and downlink carriers.

및 채널 래스터 오프셋을 제공한다. LTE/(E-UTRA) PRB 인덱스

는

로서 정의된다. 또한, NB-IoT 시스템의 상향링크 및 하향링크 중심 주파수들 사이의 오프셋은

에 따라 연기될 수 있다.

는 LTE에 대한 PRB의 위치(시퀀스 번호)이고,

는 상향링크 캐리어에 의해 점유되는 PRB의 인덱스이며,

가 양의 정수인 경우, 이것의 주파수 오프셋은 -7.5kHz이고,

가 음의 정수인 경우, 주파수 오프셋은 +7.5kHz이다. 이 경우, 상향링크 캐리어 표시 정보는 CRS 시퀀스 정보만을 포함할 수 있고, 상향링크와 하향링크 캐리어들 사이의 오프셋을 결정하기 위해 추가 표시를 사용할 필요는 없다. 상세한 구현은 상향링크 및 하향링크 오프셋 열을 표 2에 추가함으로써 수행될 수 있다.In particular, if the upper layer is configured to have the same cell ID as the in-band operating mode and the in-band operating mode, the UE performs CRS sequence and channel raster offset according to eutra-CRS-SequenceInfo (CRS sequence information), as shown in Table 2. Can decide. Table 2 shows LTE / (E-UTRA) PRB indexes corresponding to each CRS sequence information

And channel raster offset. LTE / (E-UTRA) PRB index

The

Is defined as In addition, the offset between the uplink and downlink center frequencies of the NB-IoT system is

Can be postponed depending on.

Is the location of the PRB for LTE (sequence number),

Is an index of the PRB occupied by the uplink carrier,

If is a positive integer, its frequency offset is -7.5 kHz,

If is a negative integer, the frequency offset is +7.5 kHz. In this case, the uplink carrier indication information may include only CRS sequence information, and it is not necessary to use an additional indication to determine an offset between uplink and downlink carriers. Detailed implementation can be performed by adding the uplink and downlink offset columns to Table 2.

[Table 2]

와 상향링크 및 하향링크 주파수 오프셋 방향들 간의 관계가 프로토콜에 지정될 수 있으며, 상향링크 및 하향링크 캐리어 주파수 오프셋을 추가로 결정하기 위해, 상향링크 및 하향링크 주파수 오프셋 방향이 상향링크 캐리어 표시 정보의

에 따라 결정된다. 유사하게, 가드밴드 동작 모드의 경우, MIB 또는 SIM이 PRB 인덱스, 또는 캐리어와 LTE 중심 주파수 사이의 오프셋, 또는 상향링크 캐리어가 LTE 고주파수에 위치되는지 또는 저주파수에 위치되는지 여부, 또는 가드밴드에서 동작할 수 있는 n 번째 캐리어, 및 LTE 에지로부터의 거리(예를 들어, 표 1의 파라미터들)를 나타내는데 사용될 수 있다. 또한, 전술한 다수의 정보는 하나의 인덱스를 사용하여 다수의 정보(예를 들어, LTE 시스템 대역폭, 상향링크 및 하향링크 오프셋 방향, 고주파수 또는 저주파수에 위치됨)를 나타내기 위해 함께 코딩될 수 있다.In the case of in-band operation mode or guard-band operation mode with different cell IDs, 1 bit of MIB or SIB (for example, SIB1, SIB2 or SIB22) indicates uplink and downlink frequency offset directions, or LTE center It is used to indicate that it is located in the high or low frequency part of the frequency. or,

And a relationship between uplink and downlink frequency offset directions may be specified in a protocol, and in order to additionally determine an uplink and downlink carrier frequency offset, the uplink and downlink frequency offset directions of uplink carrier indication information

It is decided according to. Similarly, in case of guardband operation mode, MIB or SIM is PRB index, or offset between carrier and LTE center frequency, or whether uplink carrier is located in LTE high frequency or low frequency, or operate in guardband Can be used to indicate the nth carrier, and the distance from the LTE edge (eg, parameters in Table 1). In addition, the aforementioned multiple pieces of information may be coded together to indicate a plurality of pieces of information (eg, LTE system bandwidth, uplink and downlink offset directions, located at high or low frequencies) using one index. .

In addition, as shown in Table 1, in the case of the guardband operation mode, since there is no uplink carrier pairing some carriers that can be used for downlink transmission, the base station can configure the uplink carrier so that the UE pairs the carriers have. The base station may configure an uplink carrier pairing downlink carriers for the UE through one or more information of PRB index, PRB index offset, and absolute frequency offset. The configuration may be configured for the UE through RRC (including system information) or MAC or physical layer indication or a combination of RRC and physical layer (PDCCH) / MAC layer. In addition, for example, through a pre-definition such as defining that a specific uplink carrier is an uplink carrier corresponding to a neighboring downlink carrier, a specific uplink carrier for a downlink carrier that does not have a paired uplink carrier Can be defined. When the base station configures carrier information corresponding to an unpaired downlink carrier for a non-independent downlink carrier, the base station needs to additionally configure the uplink and downlink frequency offset of the TDD narrowband system for the UE. There may be, this can be done using the method described above, and will not be described in detail here.

Step 1603 is performed through the above-described processing, and the center frequency of the uplink carrier corresponding to the downlink carrier is determined. Thereafter, channel signals are transmitted on the determined uplink carrier.

The above is detailed processing in the case where the one obtained in step 1601 is a downlink carrier. If this is, for example, an uplink carrier obtained in step 1601, the UE acquires an uplink carrier used to transmit a random access channel (PRACH) through higher layer signaling (eg, SIB 22), and then The indication information of the downlink carrier corresponding to the uplink carrier obtained in step 1601 needs to be obtained in step 1603, and after the uplink and downlink carrier offset in the narrowband system are determined according to the indication information, the downlink The center frequency of the carrier is calculated according to the offset. Specifically, the content of the downlink carrier indication information is similar to the indication information of the uplink carrier described above, except that the uplink carrier is replaced with the downlink carrier, where the CRS sequence information is because the CRS exists only in the downlink. The definition is the same. Similar to the case of uplink carrier indication information, the UE first determines the uplink and downlink carrier frequency offset directions according to the uplink carrier indication information, and then offsets based on the center frequency and the offset between the uplink and downlink carriers. Determines and adds an offset based on the center frequency of the uplink carrier determined in step 1601 to obtain the center frequency of the downlink carrier. Thereafter, the UE receives channel signals on the determined uplink carrier.

The foregoing is a detailed implementation of a method for transmitting signals in a TDD narrowband system according to the present disclosure. The present disclosure further provides a UE in a TDD narrowband system, and this user equipment can be used to implement the aforementioned signal transmission method. Specifically, the user equipment includes an acquisition unit, a calculation unit and a transmission unit.

The acquisition unit is configured to acquire an uplink or downlink carrier of the TDD narrowband system. If the calculation unit determines that the uplink or downlink carrier acquired by the acquisition unit is located in the in-band or guardband of the TDD broadband system, the downlink corresponding to the uplink or downlink carrier acquired by the acquisition unit Determining the indication information of the carrier or the uplink carrier, and also determining the offset between the uplink / downlink carrier and the downlink / uplink carrier in the TDD narrowband system according to the indication information, and the uplink and downlink carriers. It is configured to calculate the center frequency of the downlink or uplink carrier corresponding to the uplink or downlink carrier according to the offset and center frequency. The transmitting unit is configured to transmit signals according to the center frequency of the downlink or uplink carrier calculated by the calculating unit.

In the FDD NB-IoT system, NPRACH is transmitted on a single subcarrier with a 3.75 kHz subcarrier spacing. In each NPRACH, one symbol group consists of one CP and five symbols, and forms one NPRACH transmission for every four symbol groups. To satisfy different levels of coverage, multiple iterations for NPRACH transmission can be configured. Frequency hopping is used between symbol groups, where the hopping frequency between the first and second symbol groups and between the third and fourth symbol groups is 3.75 kHz, and hopping between the second and third symbol groups The frequency is 22.5 kHz. To reduce inter-cell interference, LTE type 2 pseudo-random frequency hopping is used before every two iterations.

The method and equipment for requesting random access of the present disclosure can be applied to a wireless communication system based on TDD, particularly a random access scenario having an LTE TDD frame structure, an LTE TDD uplink-downlink configuration and a special time slot configuration.

19 is a flowchart of a method for requesting random access according to the present disclosure.

Referring to FIG. 19, in step 1901, a TDD uplink time domain resource is determined. In step 1903, the time domain resource used to transmit the narrowband physical random access channel (NPRACH) is determined according to the TDD uplink time domain resource. In step 1905, a time domain format for an NPRACH transmission group is determined, wherein the time domain format includes at least two transmission units in which one NPRACH transmission group is discontinuous in the time domain, and one transmission unit is in the time domain. And including one or more consecutive NPRACH symbol groups. In step 1907, a time domain format NPRACH transmission group is transmitted in the time domain resource used for the determined NPRACH transmission.

20 is a flowchart of a method for predicting random access timing advance (TA) according to the present disclosure. Referring to FIG. 20, in order to receive and detect an NPRACH, a base station needs to receive and detect an NPRACH transmission group including discontinuous transmission units. This method includes the following steps.

Referring to FIG. 20, in step 2001, an NPRACH transmission group is received, where one NPRACH transmission group includes multiple discontinuous transmission units in the time domain, and one transmission unit includes one or more consecutive NPRACHs in the time domain. It includes symbol groups, and the phase between two adjacent transmission units is continuous or the phase is fixed.

In step 2003, a phase deviation is determined according to a time-frequency interval and / or a frequency domain interval between a plurality of adjacent transmission unit pairs in an NPRACH transmission group, and a timing advance (TA) is determined according to the phase deviation. . In step 2005, a TA is transmitted to indicate to the UE to adjust the time domain location for transmitting the NPRACH transmission unit.

I. TDD uplink time domain resource acquisition

The uplink time domain resource may be one or more consecutive time domain sections reserved for uplink transmission within a specific period. One continuous time domain section is a combination of multiple time units with no intervals in between, and the time units can be subframes, time slots, symbols, and the like.

When the base station configures the effective uplink subframe (s), the configured effective uplink subframe (s) is used as a TDD uplink time domain resource.

When the base station configures the effective downlink subframe (s), subframes other than the configured valid downlink subframe (s) are used as TDD uplink time domain resources (in this case, no special subframe is configured). .

When the base station configures the uplink-downlink configuration, the uplink subframe and an uplink pilot time slot (UpPTS) indicated by the uplink-downlink configuration information uplink the TDD. Used as a time domain resource. Table 3 shows examples of uplink-downlink configuration information in LTE. As shown in Table 3, for subframes of each system frame, "D" represents a downlink subframe reserved for downlink transmission, and "U" is an uplink sub reserved for uplink transmission. Frame, and "S" represents a special subframe with the following three fields: downlink pilot time slot (DwPTS), guard period (GP) reserved for downlink transmission. And an uplink pilot time slot (UpPTS) reserved for uplink transmission. The length of DwPTS and the length of UpPTS may be further configured by signaling, for example, a special subframe.

The base station may perform configuration by a radio resource control (RRC) message including a system message, a dedicated RRC configuration, and the like. In another example, the base station configures or rewrites the semi-static RRC configuration by physical layer (layer 1) signaling, eg DCI. In another example, the base station configures or rewrites the configuration by MAC signaling, for example, a MAC control element (CE), a MAC protocol data unit (PDU), or the like.

Specifically, the effective uplink or downlink subframe (s) may be configured by a bit map. For example, 10 or 40 bits represent 10 or 40 time units (eg, subframe, time slot, symbol, etc.), respectively. In the configuration method according to the bit map, a special subframe may be inserted according to a predefined rule, for example, a subframe used for downlink-to-uplink transformation is defined as a special subframe. In the configuration method by the bit map, the special subframe may be temporarily considered to be the last downlink subframe, or may not be regarded as the uplink or downlink subframe, or the first uplink subframe. Alternatively, only when the guard period between the effective uplink subframe and the effective downlink subframe is less than a specific value, GP is generated by, for example, puncturing or skipping a plurality of uplink or downlink symbols. In another example, uplink subframes may be configured by configuring a ratio (eg, 1: 1, 1: 4, etc.) between uplink subframe (s) and downlink subframe (s). The method of configuring uplink subframes by constructing a ratio between uplink subframe (s) and downlink subframe (s) can also be combined with configuring or pre-defining a period, which ratio is within this period. It indicates the ratio of uplink and downlink subframes. While calculating the ratio, the special subframe may be temporarily considered as an uplink or downlink subframe.

Configuration may be performed by different methods for different frequency-band distribution modes, such as LTE in-band deployment, LTE guardband deployment and standalone deployment. For example, with respect to LTE in-band or guard-band deployment, it is more appropriate to follow the uplink-downlink configuration for LTE directly to avoid interference to the LTE system. However, with respect to the stand-alone arrangement, configuration may be performed by configuring effective uplink or downlink subframes or by configuring a ratio.

In addition, the base station may broadcast a cell-specific uplink-downlink configuration by SIB broadcast. The base station may also reconfigure the UE specific uplink-downlink configuration by dedicated RRC signaling, Mac signaling or physical layer channel.

In addition, in the case of PUSCH or PUCCH, uplink subframes may be dynamically determined according to scheduling. For example, the UE transmits an uplink channel in PUSCH or PUCCH through time-frequency resources dynamically indicated by the physical layer. In this case, it is not necessary to acquire the TDD uplink time domain resource. That is, on the UE side, there is no need to distinguish the TDD system or the FDD system.

[Table 3] LTE uplink-downlink configurations

II. Format of NPRACH symbol group

The format of the NPRACH symbol group includes a time-frequency format. The time domain format and the frequency domain format in the time-frequency format will be described below.

시간 동안 송신된다. 하나의 심볼 그룹은 T_CP 길이의 사이클릭 프리픽스(cyclic prefix, CP)와 T_SEQ의 총 길이를 가진 5개의 동일한 심볼로 구성되며, 여기서 파라미터들은 표 4와 같다. Ts는 시간 유닛이며, 조건: 30720·T_S=1ms를 충족한다. FDD NB-IoT 시스템에서는, NPRACH 송신이 조건 n_f mod(

)을 만족하는 시스템 프레임의 시작 위치 이후

시간 유닛들로부터 시작된다.

는 NPRACH의 시작 시간이고,

는 NPRACH 리소스들의 기간이며,

및

모두는 RRC(SIB)를 통해 기지국에 의해서 구성된다.In the FDD NB-IoT system, the physical layer random access preamble is based on single subcarrier frequency hopping symbol groups. The random access preamble sequence group is composed of 4 symbol groups, and the 4 symbol groups are without gaps.

Is sent for hours. A group of symbols is composed of five identical symbols with a total length between the T-length cyclic prefix _CP (cyclic prefix, CP) and T _SEQ, wherein parameters are given in Table 4. Ts is a time unit and satisfies the condition: 30720 · T _S = 1ms. In the FDD NB-IoT system, NPRACH transmission is a condition n _f mod (

) After the start position of the system frame

It starts from time units.

Is the start time of NPRACH,

Is the period of NPRACH resources,

And

All are configured by the base station via RRC (SIB).

[Table 4] Random access preamble parameters of FDD

Since there are no continuous uplink subframes of several milliseconds in length in the TDD system, the design in the FDD NB-IoT system cannot be reused, especially in the case of LTE in-band deployment and LTE guard-band deployment. In order to allow one symbol group of NPRACH to be transmitted within the time domain range of one UpPTS + one uplink subframe, the number of symbols in the NPRACH symbol group and / or the length of CP must be reduced. For specific examples, refer to Table 5.

[Table 5] Random access preamble parameters of TDD

Table 5 shows examples of random access preamble parameters for TDD.

A1: A symbol group consisting of CPs having a length of 4480 Ts and 3 symbols with a subcarrier spacing of 3.75 kHz.

A2: A symbol group consisting of CPs having a length of 2048 Ts and 4 symbols with a subcarrier spacing of 3.75 kHz.

A3: A symbol group consisting of CP having a length of 1480Ts and 4 symbols with a subcarrier spacing of 3.75 kHz.

A4: A symbol group consisting of CP having a length of 2576TS and 4 symbols having a subcarrier spacing of 3.75 kHz.

A5: A symbol group consisting of CPs having a length of 2576 Ts and 5 symbols with a subcarrier spacing of 3.75 kHz.

A6: A symbol group consisting of CPs having a length of 672Ts and 5 symbols with a subcarrier spacing of 3.75 kHz.

By comparing Table 4 with Table 5 in relation to FDD, one symbol group in the TDD time domain format includes one CP and 3 to 5 symbols, and the total length of each symbol group is 43008 * Ts or less ( Length of T _CP + T _SEQ in preamble sequence format 0 of Table 4). That is, the total length of a single symbol group is reduced.

If other subcarrier spacings are used, the symbol length is changed accordingly. For example, at a subcarrier interval of 15 kHz, the symbol length is 2048 Ts. When the number of symbols in one symbol group is not changed, almost 1/4 Ts is reduced correspondingly. However, in order to support a specific cell coverage radius, the length of the CP must be less than approximately 2048 Ts. In other words, with respect to the subcarrier length of 15 kHz, one symbol group includes one CP and 3 to 6 symbols, and the total length of each symbol group does not exceed 14336Ts (the length of 2048Ts is One CP and 6 symbols each having a length of 2048 Ts). The number of symbols may be determined according to the length of NPRACH transmission units and the number of symbol groups in each transmission unit. When a subcarrier interval of 15 kHz or more is used, since the number of symbol groups in each transmission unit must be 2 or more (for example, 2 or 4), sufficient frequency hopping is required for each transmission unit to realize accurate TA estimation. Intervals may be provided.

It should be noted that in the above examples, a guard period (GP) may be generated at the end of the symbol group by additionally importing a TA. The above examples can be applied to different special subframe configurations. Specifically, for example:

UpPTS of one symbol + uplink subframe: A1, A2, A3 and A4;

UpPTS of 2 symbols + uplink subframe: A2, A3 and A4;

UpPTS of 3 symbols + uplink subframe: A2, A3 and A4;

UpPTS of 4 symbols + uplink subframe: A2, A4 and A5;

UpPTS of 5 symbols + uplink subframe: A2, A4, A5 and A6; And

6 symbols + UpPTS of uplink subframe: N6ACH format 0 of A6 or FDD NB-IoT.

Note: In the latter three situations, A1 and A3 can also be selected, but the GP is much longer than CP, resulting in waste.

Also, a 15 kHz subcarrier spacing may be designed. Therefore, 15 symbols may be included in an uplink subframe of 1 ms. One symbol can be used as a CP. Or, half of the symbols (1024Ts) are used as CP, and the other half is used as GP. For a special subframe plus uplink subframe, such as 3.75 kHz, approximately one symbol or half of the symbol is selected as the CP, and other symbols are used to transmit NPRACH symbols.

In addition, different timing advances need to be imported in order to adapt to transmission in this format and reserve a GP whose length is equal to CP. That is, the actual transmission time of the NPRACH occupies more uplink symbols than other uplink transmission channels or signals or proceeds by more time units. Or, the actual transmission time of the NPRACH proceeds by more time units than the uplink transmission in the LTE system. In the case of a random access channel, the additional TA does not affect the base station (BS) or terminals in the system. In the TDD system design, the GP is in a real system so that a terminal located at the cell edge and requiring a larger TA does not interfere with reception of downlink subframe (s) by the UE when using a larger TA configuration. Used to do However, in the NB-IoT system, since uplink scheduling and downlink scheduling can guarantee a GP of 1 ms, the terminal is not affected even if an additional TA is provided to the NPRACH. The specific configuration and reference time of the TA will be described in detail below.

III. NPRACH transmission

First, the format of the NPRACH transmission group will be described. The time domain format for the NPRACH transmission group may be determined according to at least one parameter of uplink configuration, special subframe configuration, NPRACH format configuration, and deployment mode.

In order to use uplink subframe (s) having a limited continuous length or a combination of uplink subframe (s) and UpPTS in a TDD system, a plurality of symbol groups can be divided into a plurality of transmission units, such transmission Units are transmitted discontinuously in the time domain. That is, a guard time is inserted between two transmission units. One transmission unit includes one or more symbol groups consecutive in the time domain. The UE transmits NPRACH in units of transmission groups, and each transmission group includes a plurality of transmission units. That is, the UE transmits one transmission group during each transmission of the NPRACH. 21 is a schematic diagram of an NPRACH transmission group. As shown in FIG. 21, one NPRACH transmission group includes multiple transmission units 2121, 2122 and 2123, which are discontinuous in NPRACH uplink resources 2101, 2102 and 2103, respectively. Is sent. Each transmitting unit includes two groups of symbols. For example, the transmission unit 2121 includes two groups of symbols 2111 and 2112; The transmitting unit 2122 includes two groups of symbols 2113 and 2114; The transmitting unit 2123 also includes two groups of symbols 2115 and 2116. After each transmitting unit, a specific time interval is reserved as a guard period (GP) (eg GP 2131, 2132 and 2133). Preferably, each transmission group includes two transmission units or three transmission units. The length of one NPRACH symbol group or the number of symbols in a symbol group is directly configured by the UE according to RRC, or is determined according to a special subframe configuration and uplink-downlink configuration of a cell. That is, the UE determines the NPRACH time-frequency format according to at least one of the received RRC signaling, special subframe configuration information, and uplink-downlink configuration information. Between different symbol groups, frequency hopping is used for timing estimation. As shown in FIG. 21, the same or different frequency hopping intervals may be used between symbol groups 2111 and 2112, between symbol groups 2113 and 2114, and between symbol groups 2115 and 2116. That is, each symbol is transmitted on a different frequency domain resource. Preferably, one or more frequency hopping intervals between symbol groups in multiple transmission units in one NPRACH transmission group are different.

The base station estimates TA according to the phase deviation between symbol groups transmitted through different frequency domain resources. By importing different frequency hopping intervals between NPRACH transmission groups, both the estimation accuracy of the TA and the supported cell radius can be improved. The BS calculates a phase deviation resulting from different time domain locations occupied by symbol groups transmitted continuously in each transmission unit, and then estimates TA based on this phase deviation. Or, the BS also estimates the TA according to different frequency domain intervals occupied by symbol groups between different discontinuously transmitted transmission units. To estimate the TA by the frequency hopping interval between symbol groups that are transmitted discontinuously, the UE may make the phase at the end of the previous symbol group equal to the phase at the beginning of the next symbol group (phases are contiguous). I) or it is necessary to ensure that the phase at the end of the previous symbol group and the phase at the beginning of the next symbol group satisfy a fixed phase deviation.

For example, the BS continuously receives the first NPRACH transmission unit, and then receives the second NPRACH transmission unit after a specific time interval X. The BS determines the TA for the UE to transmit NPRACH transmission units according to the first NPRACH transmission unit, the second NPRACH transmission unit and the specific time interval X. In addition, the BS determines the phase deviation between the symbols according to the frequency hopping interval (s) and the time interval X between the plurality of symbol groups in the NPRACH transmission units, and then determines the TA according to the phase deviation. Preferably, the phases of the two transmitting units are continuous or fixed values.

In addition, in order to increase NPRACH coverage, a UE may repeatedly transmit an NPRACH transmission group multiple times. Specifically, the UE may determine the number of repetitions N for transmissions of the NPRACH transmission group, and then repeatedly transmit the NPRACH transmission group having the time domain format N times in the determined TDD uplink time domain resource. Preferably, the BS configures one or more NPRACH resources, each NPRACH resource corresponding to a different number of repetitions N. Accordingly, the UE selects a corresponding NPRACH resource to request random access according to the level of coverage in which the UE is located.

Referring to FIG. 22, it is a schematic diagram of one transmission of the NPRACH by the UE, that is, transmission of one transmission group. For example, within two system frames (20 ms), four transmitting units are transmitted four times. One transmission unit is transmitted every 5 ms in UpPTS of a special subframe and in an uplink subframe following UpPTS. In the example of FIG. 22, each transmission unit includes one symbol group, that is, each transmission unit is composed of one CP and multiple symbols. For example, each transmitting unit is composed of one CP and 3, 4 or 5 symbols. The transmission of each transmission unit is discontinuous. In addition, since each transmission unit is followed by a downlink subframe or an uplink subframe used for uplink transmission of different channels or other UEs, a GP is added after each discontinuous transmission unit to avoid intersymbol interference. need. In FIG. 22, one transmission unit includes one symbol group. That is, the first symbol group, the second symbol group, the third symbol group, and the fourth symbol group are not continuously transmitted, and a GP is inserted after each symbol group to avoid interference. The uplink-downlink configuration of FIG. 22 is uplink-downlink configuration 2 of Table 3, and it will take 20 ms to transmit one NPRACH including four symbol groups. If uplink-downlink configuration 5 of Table 3 is used or other uplink-downlink configurations (eg, configuration 3 or configuration 4) are used in a switching period of 10 ms, 4 symbol groups are included. It will take 40 ms to transmit one NPRACH. Among the uplink-downlink configurations, two symbol groups for configuration 3 or configuration 4, or configuration 0, configuration 1, or configuration 6 may be continuously transmitted in two or three consecutive uplink subframes, Accordingly, transmission delay is reduced.

23, it is a schematic diagram of one transmission of the NPRACH by the UE, that is, transmission of one transmission group. In FIG. 23, one transmission unit includes two groups of NPRACH symbols that are continuously transmitted, which occupies one UpPTS in a special subframe and three uplink subframes after the UpPTS; Also, to avoid inter-symbol interference, a GP is needed after one transmission unit (i.e., two NPRACH symbol groups). Specifically, as shown in FIG. 21, a GP is inserted after each second symbol group and fourth symbol group. In addition, one or two NPRACH symbol groups may occupy one UpPTS and two subsequent uplink subframes. The UE may determine the transmission mode of the NPRACH according to the uplink-downlink configuration and the special subframe configuration, for example, the number of consecutively transmitted symbol groups in one transmission unit. During one NPRACH transmission, the number of symbol groups in each transmission unit may be the same or different. For example, in uplink-downlink configuration 9, one UpPTS and three uplink subframes are continuously transmitted within the first 5 ms, and one UpPTS and two uplink subframes are continuously within the last 5 ms. Is transmitted. In this case, the number of consecutively transmitted symbol groups in one transmission unit may be different.

In the embodiment shown in Figs. 22 and 23, regardless of whether the symbol groups are continuous, different symbol groups are transmitted with frequency hopping. For example, a first frequency hopping interval is used between the first and second symbol groups; Similarly, the first frequency hopping interval is also used between the third and fourth symbol groups. A second frequency hopping interval is used between the second and third symbol groups. For example, the first frequency hopping interval may be an NPRACH subcarrier interval. The first frequency hopping interval is 3.75 kHz, and the second frequency hopping interval is 22.5 kHz. The first frequency hopping interval, the second frequency hopping interval, and other frequency hopping intervals may be adjusted to different values depending on the subcarrier spacing, cell radius, multicarrier configuration, or other factors. For example, the second frequency hopping interval may be greater than the width of one carrier. Also, four symbol groups in FIG. 22 or FIG. 23 are used as one frequency hopping pattern unit. When four symbol groups are transmitted in the next frequency hopping pattern unit, a third frequency hopping interval is used between the fourth symbol group and the first symbol group in the next unit. The third frequency hopping interval may also be greater than one carrier width. Similarly, for the NPRACH channel at 15 kHz subcarrier spacing, frequency hopping can be performed at 3.75 kHz to maintain the estimated accuracy of the TA, or frequency hopping at 15 kHz to maintain the integrity of the system. You can. The second frequency hopping interval may be frequency hopping at 150 kHz or 120 kHz. Thus, the NPRACH channel can be located on two frequency domain edges of one carrier (PRB), while the interior of this carrier is reserved for NPUSCH transmission. When the symbols of the NPRACH are in a subcarrier interval of 15 kHz, the length of the symbols is 1/4 of 3.5 kHz, and in the above-described embodiments, the total number of symbols in one symbol group can be increased four times. Or, in the same continuous uplink resource, two to four symbol groups may exist in one NPRACH transmission unit. Thus, in one transmission unit, two or more frequency hopping intervals can be provided to accurately estimate the TA and support a larger cell radius.

22 and 23, the BS is between a first and second symbol group and between a third and fourth symbol group, a first predefined frequency hopping interval, and a second and third symbol group. According to the predefined second frequency hopping interval, the phase deviation resulting from the TA is calculated, and the TA is estimated according to the phase deviation and the first and second frequency hopping intervals. The frequency hopping between the first and second symbol groups and the frequency hopping between the third and fourth symbol groups may be inverse, for example, 3.5 kHz and -3.75 kHz. In a TDD system, one NPRACH transmission group consists of transmission units that are transmitted discontinuously. Thus, during the calculation of the phase deviation, the time interval X for discontinuous transmissions will be considered. Also, if the TA is estimated by phase deviation due to frequency hopping between discontinuous transmissions, it will be ensured that the phases are continuous or the phase deviation is known in advance.

In addition, the NPRACH transmission group may be repeated multiple times to meet higher coverage requirements. The BS may configure the repetition start position and repetition number of the NPRACH transmission group. The third frequency hopping interval is used between different iterations of the NPRACH transmission group. To adapt to different coverage levels, the NPRACH can be composed of one or more levels, each level corresponding to a different number of repetitions of the transmission group. At different coverage levels, the time domain format for the NPRACH transmission group can be the same or different. Also, to offload the number of UEs, the NPRACH can be composed of multiple carriers, for example non-anchor carriers, where the non-anchor carriers are carriers for which no synchronization signal is transmitted. Different transmission group formats, different number of repetitions, etc. can be configured for the NPRACH of different carriers. For example, different non-anchor carriers are deployed in different deployment modes (eg, LTE in-band deployment, LTE guardband deployment or standalone deployment).

In one example, the terminal acquires an uplink-downlink switching period for transmitting NPRACH resources that are transmitted discontinuously according to an uplink subframe configuration. For example, regardless of the uplink subframe configuration, that is, regardless of the number of uplink subframes, one or more consecutively transmitted symbol groups in the NPRACH start from the uplink-downlink switching period.

In one example, the UE determines the starting position of the first symbol group of each transmission unit according to the distribution of uplink subframes and special subframes, or a continuous uplink time domain section for one transmission unit The starting position of the first symbol group of this transmission unit is determined according to the number of uplink subframe (s).

Referring to FIG. 24, in the example of FIG. 24, each NPRACH symbol group occupies only one special subframe and one uplink subframe. Even when three consecutive uplink subframes are transmitted in the uplink subframe configuration, the NPRACH does not continuously occupy the remaining consecutive uplink subframe (s). Accordingly, these subframes can be used for transmission of other uplink channels, for example, NPUSCH.

In one example, the terminal receives the RRC direct configuration information from the BS, such that the time interval between two consecutive transmission units (start time interval between the first symbol groups of the two consecutive transmission units, or the end of the previous transmission unit) Determine the time interval between the end part of the symbol group and the head part of the first symbol group of the next transmission unit, or otherwise determine the time interval between the two transmission units). As shown in FIG. 23, the BS can directly configure a period between NPRACH symbol groups through RCC to 10 ms. In addition, one or more NPRACH formats may be defined, each format predefining a corresponding time interval value used to determine a time domain interval between two successive transmission units, thereby allowing the terminal to determine the NPRACH time-frequency format and It is possible to determine the time domain interval between two transmission units according to a predefined corresponding value.

Further, in order to use the same NPRACH format as possible in case of different uplink-downlink subframe configurations or special subframe configurations, the start position and duration of one or more symbol groups in the NPRACH can be directly configured through RRC. (As shown in FIG. 24, the duration of NPRACH transmission units can be configured). For example, the offset of one or more system frames from a particular reference point is configured directly through RRC. The reference point may be a starting position of a specific subframe. The offset is used to determine the time domain start position of one or more symbol groups (ie, transmission units) in one NPRACH transmission. As illustrated in FIG. 24, offset 1 from the start position of subframe 0 or offset 2 from the start position of special subframe (subframe 1) may be configured. Therefore, regardless of the uplink subframe configuration, the presence or absence of a special subframe, and the special subframe configuration, the NPRACH can be configured in the same manner. In different deployment modes, the same configuration method can be used. The reference point may also be an uplink subframe, a downlink subframe, a system frame, or even a symbol in a subframe, etc., and it is easily understood that the terminal determines the reference point by the TDD uplink time domain resource. The offset may also be a predetermined fixed value.

The frequency domain location for NPRACH transmission will be described below. The UE determines a frequency domain location for transmitting different NPRACH symbol groups according to an indication of the received RRC signaling, a predetermined fixed value, or downlink control signaling (ie, at least one of a carrier location, a subcarrier group and a subcarrier location) Then, a range of frequency domain resources for transmitting different NPRACH symbol groups is determined by frequency hopping. In the contention-based random access process, the UE selects a subcarrier from a subcarrier group for transmission and transmits several symbol groups in a frequency hopping scheme according to a specified frequency hopping pattern. In the scheduling based random access process, the UE transmits NPRACH according to the subcarrier configured by the BS. Preferably, the frequency hopping pattern may be predefined or determined by a cell ID, or by a random sequence generated using a cell ID as a seed. In addition, from the BS's point of view, configuring different carriers or subcarriers (groups) for NPRACH of different cells means that long-term occupancy of fixed uplink resources by NPRACH is delayed access of uplink-downlink resources or It is possible to prevent causing mismatching. In addition, frequency hopping for NPRACH can improve NPRACH detection performance and prevent inter-cell interference.

IV. NPRACH TA

The coverage range of the cell is limited by the CP and GP of the NPRACH. Therefore, GP length equivalent to CP should be inserted after at least each successive transmission. In system design, integrity will be considered while designing the symbol length (number) within CP, GP and symbol groups. For example, in the design of one UpPTS plus one uplink subframe, NPRACH is associated with downlink to ensure orthogonality of the downlink subframe after the uplink subframe or data transmitted in the downlink subframe. Can be transmitted in advance. In addition, the NPRACH can be additionally transmitted in advance with respect to other uplinks. The UE may acquire a TA through one or more of the following configurations: RRC signaling indicating that the transmission time for NPRACH is advanced by m time units (transfer of corresponding resources for UL transmission), special subframe configuration, TDD up Link-downlink configuration, batch mode, preset TA value corresponding to NPRACH format, predefined fixed TA, and the like.

22 and 23 show examples of obtaining a TA by the UE through RRC signaling indicating that the transmission time for NPRACH is advanced by m time units (the corresponding resource transfer for UL transmission). With respect to the starting position of the UpPTS, the NPRACH is transmitted by further proceeding by m time units (ie, TA values). This is performed to obtain a GP length equivalent to CP after continuous uplink transmission.

Examples in which the UE acquires TA according to a special subframe configuration and NPRACH format will be described below. Table 6 shows examples of special subframe configurations. X may be composed of 2 or 4 by the RRC parameter in SIB, thereby increasing the utilization rate of special subframes. A GP with at least one symbol length must be guaranteed.

[Table 6] Special subframe configuration in case of general CP

Specifically, with regard to the number of NPRACH formats in Table 5 and the number of symbols of different UpPTSs:

(1) UpPTS of one symbol + one uplink subframe: For example, special subframe configurations 0 to 4 in Table 6 and X = 0.

With respect to A1 in Table 5, like LTE, a GP of 4480Ts can be obtained only by a fixed TA N _TA of 624Ts for TDD, thus providing a cell radius of up to about 22 km.

With respect to A2 in Table 5, the fixed TA of the NPRACH is adjusted from 62Ts to N _TA = 2816Ts, or an additional TA offset of _N192 is added for the NPRACH, N _TAoffset , thus providing a cell radius of up to about 7.2 km. You can.

With regard to A3 in Table 5, N _TA = 5008Ts is set or N _TAoffset = 4384Ts is added, thus providing a cell radius of 12.5 km.

With regard to A4 in Table 5, N _TA = 3952Ts is set or N _TAoffset = 3328Ts is additionally added.

(2) UpPTS of two symbols + one uplink subframe: For example, special subframe configurations 5, 6, 7, 8 and 9 of Table 6, and X = 0.

Like A2 and A4 in the case of one symbol, 2 * 2192Ts can be subtracted from the corresponding TA. With regard to A3, N _TA = 624 Ts can be used directly.

(3) UpPTS of 3 symbols + one uplink subframe: For example, special subframe configurations 0, 1 and 2, and X = 2 in Table 6.

With regard to A2, A3 and A4, no additional TA is required. With regard to A3, GP becomes larger than CP.

(4) UpPTS of 4 symbols + 1 uplink subframe: For example, special subframe configurations 5, 6 and 9 of Table 6, and X = 2.

With respect to A2 and A4, direct transmission can be performed without requiring additional TA, or even N _TA can be set to 0 (ie N _TA = 0). With regard to A5, N _TA = 624Ts can be used, and cells with a cell radius of less than 3.3 km can be supported.

(5) UpPTS of 5 symbols + one uplink subframe: For example, special subframe configuration 0 of Table 6 and X = 4.

With regard to A2, A4 and A5, transmission can be performed directly. Or, with respect to A2, the fixed TA for NPRACH is adjusted from 624Ts to N _TA = 1184Ts; Alternatively, the cell radius of up to about 10 km may be provided by adding additional 560Ts TA offset N _TAoffset the NPRACH.

(6) UpPTS of 6 symbols + one uplink subframe: For example, special subframe configurations 5 and 9 of Table 4, and X = 0; Or special subframe configuration 10.

A6 can be transmitted directly by a fixed TA of 624Ts, and a cell radius of 8.6 km can be provided.

Or, for transmission of NPRACH format 0 in FDD NB-IoT, the fixed TA for NPRACH is adjusted from 624Ts to N _TA = 1184Ts; Alternatively, by adding an additional TA offset N _TAoffset of _560Ts to the _NPRACH , a cell radius of up to about 10 km can be provided.

Several time-frequency formats for the NPRACH transmission group were provided above based on the subcarrier spacing of 3.75 kHz. If the subcarrier spacing changes, the number of Ts for each symbol will change accordingly. The number of symbols in each symbol group can be calculated according to the number of Ts of the uplink time domain resource for NPRACH and the number of symbol groups in the corresponding transmission unit. In addition, the size of the corresponding CP, GP, required TA and supported cell radius are derived.

In addition, in the above-described embodiments, the NPRACH transmission uses the starting position of the UpPTS as a reference point, and the TA has been described in relation to the starting position of the UpPTS. Essentially, the count of Ts starts from the start position of each system frame or subframe. In the case of special subframes, the actual reference point is a downlink subframe / time slot. In addition, the BS can directly configure the offset transmitted by the NPRACH (eg, via RRC). The UE determines a start time for transmitting the NPRACH according to the offset. The reference time of the offset may be a start position of a specific uplink or downlink subframe, a start position of a specific system frame, or a start position of a specific symbol in a specific subframe (eg, a position of UpPTS). The reference time can be predefined in the protocol or can be configured by the BS (eg RRC).

From the system design point of view, the protocol can define one or more NRPACH formats applicable to the TDD system, and the BS can directly configure the NPRACH format for the UE. Or, the UE determines the NPRACH format according to a special subframe configuration and / or an uplink-downlink configuration.

V. Calculation of RA-RNTI

In the process of interacting with the BS to complete random access, RA-RANTI may be calculated by the UE according to one or more parameters of NRPACH format, hyper frame number, system frame, subframes, uplink-downlink configuration, etc. Can. Preferably, RA-RNTI is calculated according to the switching time between UL and DL or the configuration period of valid UL and DL subframes.

In Rel-13 and Rel-14 NB-IoT systems, the UE calculates RA-RNTI in the following way:

RA-RNTI = 1 + floor (SFN_id / 4) + 256 * carrier_id

Here, Carrier_id represents the ID (serial number) of the carrier, and SFN_id represents the ID of the system frame. In the FDD system, the time to transmit one NPRACH is 5.6 ms or 6.4 ms. In a TDD system, due to discontinuous uplink transmission, the time to transmit one NPRACH channel is extended from 20 ms to 40 ms according to different uplink subframe configurations. With respect to different NPRACH periods or switching periods of uplink and downlink subframes, different methods for calculating RA-RNTI can be selected.

For example, with respect to an NPRACH symbol group transmission period of 5 ms or an uplink-downlink switching period of 5 ms:

RA-RNTI = 1 + floor (SFN_id / 16) + 64 * carrier_id

With regard to the NPRACH symbol group transmission period of 10 ms or the uplink-downlink switching period of 10 ms:

RA-RNTI = 1 + floor (SFN_id / 32) + 32 * carrier_id

Also, if this adjustment is insufficient to meet the requirements of RA-RNTI, the hyper frame number can be additionally imported into the RA-RNTI calculation, for example:

RA-RNTI = 1 + floor (SFN_id / 64) + floor (HFN_id / 4) + 32 * carrier_id

Here, HFN_id is the ID of the hyper frame number.

In a TDD system, a UE may receive a downlink channel at an interval in which NPRACH is transmitted in an uplink subframe. In the coverage enhancement mode, the NPRACH needs to be transmitted repeatedly several times. The BS detects NPRACH and estimates TA by detecting each NPRACH transmission. For a UE under better channel conditions, the BS can successfully detect the NPRACH in advance and then obtain an accurate TA estimate. In this case, the BS may transmit a RAR (Random Access Response) in advance. For example, the starting position of the RAR window is defined on the downlink subframe before NPRACH is repeatedly transmitted. In the process of transmitting the NPRACH, the TDD UE or FD-FDD (Full Duplex FDD) UE can monitor the NPDCCH used to indicate the RAR. When the UE successfully detects the NPDCCH in response to RA-RNTI scrambling and successfully decodes the corresponding NPDSCH, the UE can stop the NPRACH transmission in advance. Accordingly, uplink transmission time can be reduced, and thus power consumption of the UE is reduced.

VI. Transmission of Msg3 and other uplink channels

In the TDD system, some uplink resources are reserved for the NPRACH channel. To avoid collision of the uplink channel and the NPRACH, Msg3 may be transmitted on the same or different carrier as the NPRACH, where the location of the carrier used to transmit the Msg3 is obtained by RRC configuration from the BS, or in advance in the system. Defined or indicated by a MAC control element (CE) (eg RAR). Similarly, other uplink channels can be scheduled with other uplink carriers for transmission via RRC, MAC or DCI.

In addition, frequency hopping between carriers may be imported for transmission of uplink channels. In one example, if the scheduling of the NPUSCH conflicts with the NPRACH, the NPUSCH will be hopped to another carrier. Other carriers are scheduled by the RRC. NPUSC includes format 1 for data transmission and / or format 2 or 3 for transmission of uplink control information. If no additional carrier is configured, transmission of the NPUSCH is postponed to a subsequent uplink subframe.

Further, the timing relationship between Msg3 and RAR may be defined to start from the first valid uplink subframe (with or without special subframe) after 12 ms.

25 is a module diagram of a UE according to the present disclosure. Referring to FIG. 25, the UE includes an uplink resource determination module 2510, a transmission resource determination module 2520, a transmission format determination module 2530, and an NPRACH transmission module 2540.

The uplink resource determination module 2510 is configured to determine a time division duplex (TDD) uplink time domain resource. The transmission resource determination module 2520 is configured to determine a time domain resource used to transmit a narrowband physical random access channel (NPRACH) according to the TDD uplink time domain resource. The transmission format determination module 2530 is configured to determine the time domain format for the NPRACH transmission group, and the time domain format is configured as follows: one NPRACH transmission group includes a plurality of discontinuous transmission units in the time domain , One transmitting unit includes one or more consecutive NPRACH symbol groups in the time domain. The NPRACH transmission module is configured to transmit an NPRACH transmission group in a time domain format in a time domain resource used to transmit the determined NPRACH.

The operating processes of the uplink resource determination module, the transmission resource determination module, the transmission format determination module and the NPRACH transmission module correspond to steps 1901, 1903, 1905 and 1907 in the method for requesting random access of the present disclosure, which will not be repeated here. .

Compared to the prior art, it can be seen from the detailed description of the present disclosure that the present disclosure has at least the following advantageous technical effects:

First, by designing a time domain format for NPRACH transmission according to the characteristics of a TDD uplink time domain resource, a random access process is arranged in an LTE band or an LTE guard band and can be applied to an NB-IoT communication system based on TDD, Accordingly, the existing NB-IoT based on FDD may be applied to the operation mode of TDD. Therefore, utilization of higher spectrum resources is achieved, and in a scenario in which multiple UEs are connected, system throughput and connection efficiency of the NB-IoT system are significantly improved;

Second, it provides a number of methods for determining the TDD uplink time domain resource and time domain transmission location of the NDDACH, and configures a time domain interval between transmission units and a start location of time domain transmission by a number of approaches. By doing so, for example, by RRC signaling, uplink-downlink subframe configuration, uplink-downlink switching period or NPRACH format, the application scenario of the random access method is enriched, and the scalability of the system is increased;

Third, by adding timing advance before the time domain location for transmitting the NPRACH, inter-symbol interference is greatly reduced, the probability of success of random access is greatly improved, and resource utilization and random access performance of the UE are optimized;

Fourth, by improving the structure and length of the existing NPRACH symbol group and adapting to the frame structure and uplink-downlink configuration in TDD mode, the method can be applied to TDD communication systems, while designing multiple NPRACH formats. , The flexibility of random access resource configuration is improved, and thus the access efficiency is improved; Also

Fifth, the accuracy of the TA estimation is greatly improved by the base station estimating the TA according to the time-frequency interval and the frequency domain interval between adjacent transmission units in the NPRACH transmission group in the time domain format, and then feeding the TA back to the UE, The probability of success of random access is increased.

Those skilled in the art should understand that the present invention includes devices for performing one or more operations as described in the present disclosure. These devices can be specially designed and manufactured as intended, or can include well-known devices in general purpose computers. Computer programs that are selectively activated or reconfigured are stored in these devices. Such computer programs are suitable for storing a device (e.g., computer) readable medium or electronic instructions and may be stored in any type of media each coupled to a bus, and the computer readable media can be any type of disk (floppy). Disks, including hard disks, optical disks, CD-ROMs, and magneto-optical disks), Read-Only Memory (ROM), Random Access Memory (RAM), Erasable Programmable Read-Only Memory (EPROM), and Electrically Erasable Programmable (EEPROM) Read-Only Memory), flash memory, magnetic cards, or optical line cards. In other words, readable media includes any medium that stores or transmits information in a device (eg, computer) readable form.

Those skilled in the art should understand that computer program instructions may be used to implement each block of the structural diagrams and / or block diagrams and / or flowcharts and combinations of blocks of the structural diagrams and / or block diagrams and / or flowcharts. A person skilled in the art can provide and implement such computer program instructions to a general purpose computer, a special purpose computer, or other processors of a programmable data processing means, such that blocks or blocks of the structural diagrams and / or block diagrams and / or flowcharts disclosed by the present disclosure are disclosed. It should be understood that the solutions specified in can be executed by a computer or other processor of a programmable data processing means.

It should be understood by those skilled in the art that steps, measurements and solutions in the operations, methods and flows already discussed in the present disclosure can be replaced, altered, combined or deleted. In addition, other steps, measurements and solutions in the operations, methods and flows already discussed in the present disclosure may also be replaced, altered, reconstructed, disassembled, combined or deleted. In addition, steps, measurements, and solutions of the prior art in the operations, methods, and operations disclosed in this disclosure may also be replaced, altered, reconstructed, disassembled, combined, or deleted.

The foregoing descriptions are only some implementations of the present disclosure. Various improvements and modifications can be made to those skilled in the art without departing from the principles of the present disclosure, and such improvements and modifications should be considered to fall within the protection scope of the present disclosure.

Claims (15)

A method of operating user equipment (UE) in a wireless communication system,
Determining a carrier for uplink control information (UCI) transmission from at least two carriers for uplink transmission;
The at least two carriers are assigned to the UE in the cell currently connected by the UE,
Determining a relative frequency domain position and a time domain start position occupied by the UCI on the determined carrier for UCI transmission;
Re-adjusting the center radio frequency of the UE to the center frequency of the carrier for the UCI transmission,
Transmitting the UCI according to the relative frequency domain position and the time domain start position occupied by the UCI.
How to include.
According to claim 1,
The carrier for the UCI transmission is different from the carrier used for uplink data transmission of the UE, or the carrier for the UCI transmission is different from the uplink carrier corresponding to the downlink channel of the UE.
According to claim 1,
Determining at least two carriers for the uplink transmission according to the first signaling transmitted from the base station, or
The random access channel determines an uplink carrier corresponding to a carrier or a downlink anchor carrier transmitted as one carrier for uplink transmission, and according to a second signaling transmitted from the base station or according to a predefined rule. Determining other carriers for uplink transmission accordingly
The method further comprising.
According to claim 1,
Determining the carrier for the UCI transmission,
Determining a carrier for the UCI transmission according to the third signaling transmitted from the base station-or
And determining a carrier for the UCI transmission according to the first signaling or the second signaling,
The third signaling is to indicate the carrier for the UCI transmission from the carriers for the uplink transmission
Constructed, method.
According to claim 1,
Determining the starting point of the time domain occupied by the UCI is:
Determining a first effective uplink transmission position starting from an end position of a downlink data channel and satisfying a specified time offset as the time domain start position,
The specified time offset is a preset minimum time offset, or the specified time offset is a time offset determined according to signaling transmitted from the base station.
As a method of operating a base station in a wireless communication system,
Determining a carrier for transmission of uplink control information (UCI) of user equipment (UE) from at least two carriers for uplink transmission;
The at least two carriers are assigned to the UE in the cell currently connected by the UE,
Determining a relative frequency domain position and a time domain start position occupied by the UCI on the determined carrier for UCI transmission;
Receiving the UCI in a carrier for the UCI transmission of the UE according to the relative frequency domain location and the time domain start location occupied by the UCI.
How to include.
A method for operating a user equipment (UE) to transmit signals in a time division duplex (TDD) narrowband system,
Acquiring a first carrier of the TDD narrowband system,
When the uplink or downlink carrier determined as the first carrier is located in an inband or guardband of a TDD broadband system, obtaining indication information of a second carrier corresponding to the first carrier Wow,
Determining an offset between the first carrier and the second carrier of the TDD narrowband system according to the indication information,
Calculating a center frequency of the second carrier corresponding to the first carrier according to the offset and the center frequency of the first carrier,
And transmitting and receiving signals according to the calculated center frequency of the second carrier,
When the first carrier is an uplink carrier, the second carrier is a downlink carrier; If the first carrier is a downlink carrier, the second carrier is an uplink carrier.
The method of claim 7,
If the first carrier is a downlink carrier, the downlink carrier is an anchor carrier or a non-anchor carrier.
The method of claim 7,
The indication information of the second carrier is configured in a system information block (SIB) or a master information block (MIB).
The method of claim 7,
The indication information of the second carrier includes offset information from the center frequency of the first carrier, information of physical resource blocks occupied by the TDD broadband system, relative position information for the TDD broadband system, cell specific reference signal (cell -specific reference signal, CRS) method comprising at least one of the sequence information.
The method of claim 7,
The UE determines that the first carrier is located in the in-band or the guard-band of the TDD broadband system, a synchronization channel, a master information block, a system information block, a UE specific radio resource control (RRC) The UE determines that the first carrier is within the in-band or the guard-band of the TDD broadband system according to one or more channels or information of signaling, physical layer indication information, or MAC (Media Access Control) layer indication information. The method, which includes doing.
The method of claim 7,
When the first carrier is an uplink carrier, the uplink carrier obtained by the UE is an uplink carrier used for transmitting a random access channel.
A method of operating user equipment (UE) for requesting random access in a wireless communication system,
Determining a time division duplex (time division duplex , TDD) uplink time domain resource,
Determining a time domain resource used to transmit a narrowband physical random access channel (NPRACH) according to the TDD uplink time domain resource;
Determining a time domain format for the NPRACH transmission group;
The time domain format is configured such that one NPRACH transmission group includes at least two transmission units that are discontinuous in the time domain, and one transmission unit includes one or more consecutive NPRACH symbol groups in the time domain,
In the time domain resource used to transmit the determined NPRACH, transmitting the NPRACH transmission group in the time domain format.
How to include.
A method for predicting a random access timing advance (TA) by a base station in a wireless communication system,
Receiving a narrowband physical random access channel (NPRACH) transmission group;
One NPRACH transmission group includes a plurality of discontinuous transmission units in the time domain, one transmission unit includes one or more consecutive NPRACH symbol groups in the time domain, and the phases between two adjacent transmission units are continuous or Or the phases are fixed,
Determining a phase deviation according to a time-frequency interval and / or a frequency domain interval between a plurality of adjacent transmission unit pairs in the NPRACH transmission group, and determining a TA according to the phase deviation;
Transmitting the TA to indicate to user equipment (UE) to adjust the time domain location for transmitting the NPRACH transmission unit
How to include.
Apparatus configured to implement the method of claim 1.

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