KR102289117B1 - Method and apparatus for transmitting uplink data in wireless communication system supporting device to device communication - Google Patents

Abstract

The present specification provides a method and apparatus for transmitting uplink data in a wireless communication system supporting inter-terminal communication. In this specification, in a method for transmitting uplink control information (Uplink Control Information) by a terminal to a base station on a Physical Uplink Shared Channel (PUSCH) in a wireless communication system supporting D2D (Device to Device) communication, Receiving D2D configuration information including information on a monitoring interval for monitoring a D2D signal from the base station, receiving an uplink grant indicating transmission of the PUSCH from the base station, the uplink grant When instructs transmission of the PUSCH in the monitoring period, processing the uplink grant, calculating a coding rate for the uplink control information at a timing of retransmission of the PUSCH, and performing PUSCH rate matching and transmitting the uplink control information to the base station on the PUSCH, wherein the coding rate calculation and rate matching are performed based _{on a fixed variable (N SRS ) value regarding whether SRS is transmitted.} .

Description

Method and apparatus for transmitting uplink data in a wireless communication system supporting inter-terminal communication

The present invention relates to wireless communication, and more particularly, to a method and apparatus for transmitting uplink data during a monitoring period for receiving a D2D signal by a terminal in a wireless communication system supporting device-to-device communication.

Device-to-device (D2D) communication is a communication method that has been possible since the days of analog radios, and has a very long history. However, D2D communication in a wireless communication system is differentiated from existing D2D communication.

D2D communication in a wireless communication system is a communication in which terminals geographically close to each other directly exchange data in a frequency band of the wireless communication system or other bands using the transmission/reception technology of the wireless communication system without going through an infrastructure such as a base station. means This enables the terminal to use wireless communication outside of the area where the wireless communication infrastructure is built, and provides advantages of reducing the network load of the wireless communication system.

On the other hand, a terminal supporting D2D communication in a wireless communication system can also perform general wireless communication (ie, communication with the serving base station using a cell (carrier) provided by the serving base station). there is. To this end, the serving base station transmits an uplink grant indicating transmission of a Physical Uplink Shared Channel (PUSCH) to the UE in the cell. The PUSCH carries an uplink shared channel (UL-SCH), and uplink data (data to be transmitted to the base station) is transmitted through the UL-SCH.

However, a terminal supporting D2D communication (D2D terminal) needs to monitor whether a D2D signal from another D2D terminal is received for D2D communication. Therefore, when the uplink grant received from the base station instructs transmission of PUSCH during the period for monitoring the D2D signal, a terminal having a single transceiver chain (ie, a terminal that cannot perform transmission and reception at the same time) cannot transmit PUSCH or monitor D2D signals. In addition, even if the D2D terminal can simultaneously perform transmission and reception, if the PUSCH is transmitted during the period for monitoring the D2D signal, the transmission signal of the D2D terminal is received by the D2D terminal. ) will occur.

In order to solve this problem, there is a need for a method for more effectively transmitting and receiving D2D signals while minimizing the influence on the existing LTE signals.

An object of the present invention is to provide a method and apparatus for transmitting uplink data of a terminal in a wireless communication system supporting inter-terminal communication.

Another technical object of the present invention is to provide a method and apparatus capable of minimizing the influence of terminal-to-terminal communication on the wireless communication system during terminal-to-terminal communication in a wireless communication system supporting terminal-to-terminal communication.

According to an aspect of the present invention, in a wireless communication system supporting device-to-device (D2D) communication, uplink control information is transmitted by a terminal to a base station on a Physical Uplink Shared Channel (PUSCH). A method is provided. The transmission method includes: receiving D2D configuration information including information on a monitoring interval for monitoring a D2D signal from the base station; receiving an uplink grant indicating transmission of the PUSCH from the base station; When the uplink grant indicates transmission of the PUSCH in the monitoring period, the uplink grant is processed and a coding rate for the uplink control information is calculated at a timing of retransmission of the PUSCH, and PUSCH rate matching and transmitting the uplink control information to the base station on the PUSCH, wherein the coding rate calculation and rate matching are performed based _{on a fixed variable (N SRS ) value regarding whether SRS is transmitted or not.} can be implemented.

According to another aspect of the present invention, a terminal for transmitting uplink control information (Uplink Control Information) to a base station on a PUSCH (Physical Uplink Shared Channel) in a wireless communication system supporting D2D (Device to Device) communication is provided do. The terminal includes a monitoring unit for monitoring a D2D signal based on the information on the monitoring section received from the base station, a coding rate calculation unit for calculating a coding rate for the uplink control information, and a rate matching unit for performing PUSCH rate matching , the coding rate calculation and the rate matching in the coding rate calculating unit and the rate matching unit may be implemented to be performed based on a value _{of a fixed variable (N SRS ) regarding whether SRS is transmitted.}

According to the present invention, when communication between terminals in a wireless communication system, the influence of the communication between terminals on the wireless communication system can be minimized, and the terminal can flexibly perform uplink transmission and D2D communication.

1 is a diagram illustrating a wireless communication system to which the present invention is applied.
2 is a diagram for explaining the concept of cellular network-based D2D communication applied to the present invention.
3 is a diagram illustrating an operation when PUSCH transmission is indicated on a measurement cap in an LTE system.
5 is a diagram illustrating a case of initial PUSCH transmission and SRS transmission on the same serving cell within a monitoring period according to an embodiment of the present invention.
6 is a diagram illustrating a case of initial PUSCH transmission and SRS transmission on another serving cell within a monitoring period according to an embodiment of the present invention.
7 is a flowchart illustrating operations of a base station and a terminal according to an embodiment of the present invention.
8 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.

Hereinafter, in the present specification, contents related to the present invention will be described in detail through exemplary drawings and embodiments together with the contents of the present invention. In adding reference numerals to components in each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the embodiments of the present specification, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present specification, the detailed description thereof will be omitted.

In addition, this specification describes a wireless communication network, and the work performed in the wireless communication network is performed in the process of controlling the network and transmitting data in a system (eg, a base station) having jurisdiction over the wireless communication network, or the corresponding wireless communication network. An operation may be performed in a terminal included in the network.

1 is a diagram illustrating a wireless communication system to which the present invention is applied.

Referring to FIG. 1 , a wireless communication system 10 may provide a communication service between a base station and a terminal. In a wireless communication system, a terminal and a base station may wirelessly transmit and receive data. In addition, the wireless communication system may support device-to-device (D2D) communication between the terminal and the terminal. A wireless communication system supporting D2D communication will be described later.

In the wireless communication system 10 , a base station (BS) 11 may provide a communication service to a terminal existing within the transmission coverage of the base station through a specific frequency band. The coverage serviced by the base station may also be expressed in terms of a site. A site may include a plurality of regions 15a, 15b, and 15c, which may be referred to as sectors. Each sector included in the site may be identified based on a different identifier. Each of the sectors 15a, 15b, and 15c may be interpreted as a partial area covered by the base station 11 .

The base station 11 generally refers to a station that communicates with a UE (User Equipment, 12), an evolved-NodeB (eNodeB), a Base Transceiver System (BTS), an access point (Access Point), a femto base station ( Femto eNodeB), home base station (HeNodeB: Home eNodeB), relay (relay), may be called other terms such as remote radio head (RRH: Remote Radio Head).

The terminal 12 may be fixed or mobile, and may include a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, and a personal digital assistant (PDA). , a wireless modem, a handheld device, and the like.

The base station 11 may be referred to by various terms such as a megacell, a macrocell, a microcell, a picocell, and a femtocell, depending on the size of coverage provided by the base station. A cell may be used as a term indicating a frequency band provided by a base station, coverage of the base station, or a base station.

Hereinafter, downlink means a communication or communication path from the base station 11 to the terminal 12 , and uplink means a communication or communication path from the terminal 12 to the base station 11 . do. In the downlink, the transmitter may be a part of the base station 11 , and the receiver may be a part of the terminal 12 . In the uplink, the transmitter may be a part of the terminal 12 , and the receiver may be a part of the base station 11 .

There is no limitation on the multiple access technique applied to the wireless communication system 10 . For example, Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA (SC-FDMA), OFDM-FDMA , OFDM-TDMA, and various multiple access schemes such as OFDM-CDMA can be used. These modulation techniques increase the capacity of the communication system by demodulating signals received from multiple users of the communication system. In addition, a Time Division Duplex (TDD) method transmitted using different times or a Frequency Division Duplex (FDD) method transmitted using different frequencies may be used for uplink transmission and downlink transmission.

The layers of the radio interface protocol between the terminal and the base station are based on the lower three layers of the Open System Interconnection (OSI) model widely known in communication systems, the first layer (L1), the second layer It may be divided into a second layer (L2) and a third layer (L3).

The physical layer belonging to the first layer provides an information transfer service using a physical channel. The physical layer is connected to a media access control (MAC) layer, which is an upper layer, through a transport channel. Data is transmitted through a transport channel between the MAC layer and the physical layer. Transport channels are classified according to how data is transmitted through the air interface. In addition, data is transmitted through a physical channel between different physical layers (ie, between the physical layers of the terminal and the base station). The physical channel may be modulated in an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and uses time and frequency and a space generated by a plurality of antennas as radio resources.

For example, PDCCH (Physical Downlink Control CHannel) among physical channels informs the UE of resource allocation of PCH (Paging CHannel) and DL-SCH (DownLink Shared CHannel) and HARQ (Hybrid Automatic Repeat Request) information related to DL-SCH, An uplink scheduling grant informing the UE of resource allocation of uplink transmission may be carried. In addition, a Physical Control Format Indicator CHannel (PCFICH) informs the UE of the number of OFDM symbols used for PDCCHs, and is transmitted every subframe. In addition, a Physical Hybrid ARQ Indicator CHannel (PHICH) carries a HARQ ACK/NAK signal in response to uplink transmission. In addition, PUCCH (Physical Uplink Control CHannel) carries HARQ ACK/NAK for downlink transmission, scheduling request, and uplink control information such as Channel Quality Indicator (CQI) and rank indicator (RI).

The RI is information on a rank (that is, the number of layers) recommended by the UE. That is, RI indicates the number of independent streams used for spatial multiplexing. RI is fed back only when the UE operates in MIMO mode using spatial multiplexing. An RI is always associated with one or more CQI feedbacks. That is, the fed back CQI is calculated assuming a specific RI value. Since the rank of a channel generally changes more slowly than the CQI, the RI is fed back fewer times than the CQI. The RI transmission period may be a multiple of the CQI/PMI transmission period. RI is given for the entire system band, and frequency-selective RI feedback is not supported.

In addition, a Physical Uplink Shared CHannel (PUSCH) carries an UpLink Shared CHannel (UL-SCH). When necessary according to the configuration and request of the base station, the PUSCH may include CSI (Channel State Information) information such as HARQ ACK/NACK and CQI.

The data link layer corresponding to the second layer of the OSI model includes a MAC layer, a Radio Link Control (RLC) layer, and a Packet Data Convergence Protocol (PDCP) layer.

The MAC layer performs multiplexing or demultiplexing to a transport block provided as a physical channel on a transport channel of a MAC SDU (Service Data Unit) belonging to a logical channel and a transport channel and a mapping between a logical channel and a logical channel. can do. The MAC layer provides services to the RLC layer through logical channels. The logical channel can be divided into a control channel for transmitting control domain information and a traffic channel for transmitting user domain information. For example, as services provided from the MAC layer to an upper layer, there is data transfer or radio resource allocation.

The RLC layer may perform concatenation, segmentation, and reassembly of RLC SDUs. The RLC layer has three types of transparent mode, unacknowledged mode, and acknowledged mode to ensure various QoS (Quality of Service) required by radio bearer (RB). operation mode is provided.

The PDCP layer may perform user data transfer, header compression and ciphering, and control plane data transfer and encryption/integrity protection.

The RRC (Radio Resource Control) layer belonging to the third layer of the OSI model is related to configuration, re-configuration, and release of RBs and is responsible for controlling logical channels, transport channels and physical channels. . RB means a logical path provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, PDCP layer) for data transfer between the terminal and the network. Configuring the RB means a process of defining the characteristics of a radio protocol layer and a channel to provide a specific service, and setting each specific parameter and operation method. The RB may be divided into a signaling RB (SRB) and a data RB (DRB). The SRB is used as a path for transmitting RRC messages and NAS (Non-Access Stratum) messages in the control plane, and the DRB is used as a path for transmitting user data in the user plane. Hereinafter, simply expressing RB without distinguishing between SRB and DRB means DRB.

2 is a diagram for explaining the concept of cellular network-based D2D communication applied to the present invention.

D2D communication may refer to a technology for directly transmitting and receiving data between terminals. Hereinafter, it is assumed that the terminal supports D2D communication in an embodiment of the present invention. In addition, D2D may be replaced by an expression such as proximity based service (ProSe) or ProSe-D2D. The use of the term ProSe for D2D means that the meaning of a technology for directly transmitting and receiving data between terminals is not changed, but the meaning of an access-based service can be added.

Recently, a method of performing discovery and direct communication between devices in network coverage or out-of-coverage for the purpose of public safety, etc. has been proposed. is being studied. A terminal that transmits a signal based on inter-terminal communication may be defined as a transmitting terminal (Tx UE), and a terminal that receives a signal based on inter-terminal communication may be defined as a receiving terminal (Rx UE). The transmitting terminal may transmit a discovery signal, and the receiving terminal may receive the discovery signal. The roles of the transmitting terminal and the receiving terminal may be changed. Meanwhile, a signal transmitted by the transmitting terminal may be received by two or more receiving terminals.

In the cellular system, when terminals in close proximity perform D2D communication, the load of the base station may be distributed. In addition, when adjacent terminals perform D2D communication, since the terminals transmit data over a relatively short distance, consumption of transmission power and transmission latency of the terminal may be reduced. In addition, from the perspective of the entire system, the existing cellular-based communication and the D2D communication use the same resource, so the frequency utilization efficiency can potentially be improved, but the interference between each other must be considered, so that transmission is based on different subframes. .

D2D communication may be divided into a communication method of a terminal located within (in-coverage) of network coverage (base station coverage) and a communication method of a terminal located outside of network coverage (out-of-coverage).

Referring to FIG. 2 , communication between a first terminal 210 located in a first cell and a second terminal 220 located in a second cell, and a third terminal 230 located in the first cell and a first terminal located in the first cluster Communication between the 4 terminals 240 may be D2D communication within network coverage. Communication between the fourth terminal 240 located in the first cluster and the fifth terminal 250 located in the first cluster may be D2D communication outside the network coverage. Here, the fifth terminal 250 may operate as a cluster head (CH) of the first cluster. Here, the cluster head refers to a terminal (or unit) that can be referenced for at least synchronization purposes, and refers to a terminal in charge of allocating resources from time to time according to different purposes. The cluster header may include an independent synchronization source (ISS) for synchronization of the UE out of coverage.

D2D communication may be divided into a discovery procedure for performing discovery for communication between terminals and a direct communication procedure for transmitting and receiving control data and/or traffic data between terminals. D2D communication can be used for various purposes. For example, D2D communication within network coverage may be used for public safety, ultra-low latency service, commercial purpose service, and the like. D2D communication outside of network coverage may be used only for public safety.

As an embodiment of performing D2D communication, the base station 200 may transmit D2D resource allocation information to the first terminal 210 . The first terminal 210 is a terminal located within the coverage of the base station 200 . The D2D resource allocation information may include allocation information on transmission resources and/or reception resources that can be used for D2D communication between the first terminal 210 and another terminal (eg, the second terminal 220 ).

Upon receiving the D2D resource allocation information from the base station, the first terminal 210 may transmit the D2D resource allocation information to the second terminal 220 . The second terminal 220 may be a terminal located outside the coverage of the base station 200 . The first terminal 210 and the second terminal 220 may perform D2D communication based on D2D resource allocation information. Specifically, the second terminal 220 may obtain information about the D2D communication resource of the first terminal 210 . The second terminal 220 may receive data transmitted from the first terminal 210 through a resource indicated by the information on the D2D communication resource of the first terminal 210 .

In D2D communication, a UE may transmit physical layer control data to another UE. Here, in D2D communication, physical layer control data for synchronization may be transmitted through a synchronization channel, for example, may be provided through a Physical D2D Synchronization CHannel (PD2DSCH) channel. The physical layer control data for the data communication may be transmitted through scheduling assignment (SA), and may be provided through a channel format similar to the PUSCH format for D2D communication or a slightly improved PUSCH format. . And, in D2D communication, actual traffic data that is distinguished from physical layer control data may be expressed in terms of D2D data.

Additionally, a method for transmitting higher layer control data other than the physical layer in D2D communication may be defined.

During D2D communication, the terminal may operate in a first transmission mode and a second transmission mode. The first transmission mode is a mode in which the terminal can perform D2D communication only when resources for D2D communication are allocated from the base station. The base station transmits the D2D grant to the transmitting terminal for the purpose of D2D resource allocation. The D2D grant includes parameter information to be determined by the base station among scheduling assignment (SA) information, which is control information to be secured for D2D data reception by the receiving terminal during D2D communication, for example, resource allocation (RPT) for the SA. Resource Pattern for Transmission)/power control/TA information and the like and resource allocation (RPT, Resource Pattern for Transmission)/power control/TA information for data indicated by the SA are instructed to the transmitting terminal. The parameter information to be determined by the base station includes resource allocation information for data indicated by the SA, and the like. The D2D grant may be delivered to the transmitting terminal through an (E)PDCCH channel including downlink control information (DCI). The D2D grant is control information that is used for D2D purposes through an uplink grant or a D2D-RNTI allocated to each UE. The D2D grant may be expressed as an SA/data grant.

On the other hand, the second transmission mode is a mode in which the terminal can perform D2D communication in an environment without an instruction from the base station (out of coverage) or in an environment (in coverage) mode using only a limited instruction from the base station. D2D data may be transmitted by internally arbitrarily selecting a resource to be used from among radio resources. The terminal has information indicating that a specific cell in the base station can support D2D through SIB (System Information Block)/dedicated signaling and D2D resource pool information for the second transmission mode provided from the base station. Only when it exists, it can operate in the second transmission mode only for the specific cell. When information indicating that a specific cell in the base station can support D2D exists but D2D resource pool information for the second transmission mode is not provided from the base station, the RRC connected mode is used to operate in the second transmission mode. After switching, it can be performed in the second transmission mode through dedicated RRC signaling. However, when the terminal is located in a non-network service area, that is, in 'Any Cell Selection' mode, which is a case in which a serviceable cell is not selected although an RRC idle mode terminal, the UICC (Universal Subscriber Identity (USIM) of the terminal) Module) The second transmission mode using D2D resource pool information for the second transmission mode stored in the Integrated Circuit Card), etc. or using the D2D resource pool information for the second transmission mode received through the base station in the previous network service area. can operate as

In a wireless communication system, the terminal reports its buffer status to the base station in order to be allocated resources necessary for transmitting uplink data (data to be transmitted to the base station) existing in the buffer in the terminal, and the base station reports the buffer status reported from the terminal. A resource to be allocated to each terminal is scheduled based on the information.

Therefore, when the wireless communication system supports D2D communication, the base station needs to schedule resources required for terminals existing in in-coverage to transmit data in mode 1 D2D communication. It is necessary to know how much data (hereinafter referred to as D2D data) exists in the buffer of D2D communication. To this end, the terminal may notify the base station of how much data is to be transmitted through D2D communication in the buffer in the terminal through the following procedure.

Meanwhile, a terminal (D2D terminal) supporting D2D communication in a wireless communication system may also perform wireless communication (eg, LTE communication) using a base station. Wireless communication using a base station may mean communication performed by a terminal with a serving base station using a cell (carrier) provided by a serving base station. To this end, the serving base station may transmit an uplink grant instructing transmission of a Physical Uplink Shared Channel (PUSCH) to the UE in the cell. PUSCH carries an Uplink Shared Channel (UL-SCH). Uplink data is transmitted to the base station through the UL-SCH.

However, the D2D terminal needs to monitor whether a D2D signal from another D2D terminal is received for D2D communication. Therefore, when the uplink grant received from the base station instructs transmission of the PUSCH during the period for monitoring the D2D signal, a terminal having a single transceiver chain (ie, transmitting or receiving simultaneously on two or more carriers) is performed. UE) cannot transmit PUSCH on different carriers or monitor D2D signals. In addition, even if the D2D terminal can perform transmission and reception simultaneously, when the PUSCH is transmitted during the period for monitoring the D2D signal, the transmission signal of the D2D terminal is generally received by the D2D terminal on an adjacent UL spectrum band. There is a problem in that self-interference occurs. Therefore, a method of transmitting a PUSCH without such a problem will be described below.

3 is a flowchart illustrating a PUSCH transmission method according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating an operation when PUSCH transmission is indicated on a measurement cap set on a DL spectrum/subframe, FIG. 5 and 6 are diagrams illustrating a case of performing initial PUSCH transmission and SRS transmission within a monitoring period according to an embodiment of the present invention.

Referring to FIG. 3 first, the D2D terminal may receive D2D configuration information for D2D communication from the base station (S310). The D2D communication includes, of course, D2D discovery and D2D data communication. The D2D configuration information is transmitted to each D2D through a System Information Block (SIB) and/or dedicated RRC signaling according to the type of D2D discovery (type 1/2B) or the mode (mode 1/2) of D2D data communication. may be transmitted to terminals. For example, when the terminal is set to the first transmission mode, the terminal may perform D2D communication using a resource allocated from the base station. In addition, when the second transmission mode is set, D2D communication may be performed using internally selectable resources within the D2D resource pool.

Meanwhile, the information on the D2D resource pool may include information on a D2D signal monitoring period (monitoring resource information), and the monitoring period is present on other resources (eg carrier) not currently monitored by the UE. It is a time period that can be set by the serving base station to receive the D2D signal or can be recognized based on information obtained through the initial access operation on other resources (eg carrier/PLMN) by the terminal itself. The monitoring resource information may exist in the same form or as a subset of the information on the D2D resource pool. For example, the monitoring resource information includes a period (eg, a discovery signal) for monitoring D2D signals (eg, discovery signals) of D2D terminals connected to a Public Land Mobile Network (PLMN) that provides a serving cell to the terminal. , subframe) may be included. Here, the PLMN means a network of a mobile communication network operator or an identification number of the corresponding network. The network may distinguish a network operator operating a corresponding frequency to the terminal through the identifier of the corresponding network, and may obtain information on access rights (eg, Access Class Barring).

Alternatively, the monitoring resource information includes information on a period for monitoring D2D signals of D2D terminals connected to a serving PLMN (PLMN) that provides a serving cell to the terminal as well as information on a neighboring or different PLMN. It may include information on a period for monitoring D2D signals for D2D terminals. In order to efficiently monitor D2D signals of D2D terminals connected to different cells (Inter-Cell) as well as D2D signals of D2D terminals connected to different PLMNs (Inter-PLMN), a specific monitoring period is set in the D2D terminal. Because it may need to be. In this way, when a monitoring period adjacent to the terminal or for another PLMN is set/acquired, the D2D signal reception efficiency is increased and battery consumption is increased because it is only necessary to monitor the D2D signal from another PLMN (carrier) or an adjacent cell in the corresponding monitoring period. can be reduced.

Meanwhile, the terminal may receive an uplink grant indicating transmission of SRS and PUSCH from the base station (S320). The uplink grant may be received before a transmission mode (first transmission mode and second transmission mode) for D2D data communication or transmission type (type 1 and type 2B) for D2D discovery is configured in the terminal, D2D It may be received after the transmission mode/discovery type is set. When the uplink grant is received after the D2D transmission mode is configured in the terminal through the D2D configuration information, the terminal determines whether the timing at which the uplink grant indicates transmission of SRS and PUSCH is included in the monitoring period for D2D communication can be confirmed (S330).

If the uplink grant indicates transmission of SRS and PUSCH within a monitoring period for D2D communication, the UE processes the uplink grant to receive the D2D signal, but SRS and PUSCH may not be transmitted to the base station Keep. In addition, transmission may be performed at the next SRS and PUSCH retransmission timing according to a non-adaptive retransmission procedure (S340). Here, the non-adaptive retransmission is a response (feedback) of uplink transmission to the timing at which PUSCH transmission is instructed, without HARQ ACK/NACK from the base station. It may mean that the SRS and PUSCH are retransmitted at the next SRS and PUSCH transmission opportunity. there is. To this end, for example, the UE stores the uplink grant received from the HARQ entity when the uplink grant indicates transmission of SRS and PUSCH within the monitoring period for D2D communication, but the physical layer corresponds to the PHY layer. It may not indicate transmission. However, if the uplink grant indicates transmission of SRS and PUSCH outside the monitoring period for D2D communication, the UE may transmit SRS and PUSCH at the indicated timing (S350).

That is, as shown in FIG. 4 , the D2D terminal is a terminal having a single transceiver chain is instructed to transmit a PUSCH over a measurement gap, within the monitoring period for D2D communication. When the PUSCH transmission is instructed, the PUSCH may be transmitted without HARQ feedback at the next PUSCH retransmission timing. Here, the measurement gap means a period for checking and measuring cells corresponding to the remaining frequencies (inter-frequency and/or inter-RAT (Radio Access Technology)) excluding the carrier frequency of the serving cell. The measurement gap is divided into a first gap pattern repeating at a period of 40 ms and having a length of 6 ms and a second gap pattern repeating at a period of 80 ms and having a length of 6 ms, as shown in Table 1 below. Any one of the two patterns may be set by the network in the terminal.

Gap Pattern Id MeasurementGap Length (MGL, ms) Measurement Gap Repetition Period
(MGRP, ms) Minimum available time for inter-frequency and inter-RAT measurements during 480ms period
(Tinter1, ms) Measurement Purpose 0 6 40 60 Inter-Frequency E-UTRAN FDD and TDD, UTRAN FDD, GERAN, LCR TDD, HRPD, CDMA2000 1x One 6 80 30 Inter-Frequency E-UTRAN FDD and TDD, UTRAN FDD, GERAN, LCR TDD, HRPD, CDMA2000 1x

A trade-off exists between the first pattern and the second pattern. The first pattern interferes with transmission and reception of the serving cell instead of having a short period. On the other hand, the second pattern gives less disturbance than the first pattern instead of having a longer period. The terminal cannot transmit any data to the base station during the measurement gap.

In FIG. 4, as an example, when the n + 2 th subframe to the n + 7 th subframe is set as a measurement gap in the terminal, the terminal in the n th subframe receives the n + 4 th subframe from the base station for the first time (initial). ) A case in which an uplink grant indicating PUSCH transmission is received is illustrated. In this case, the UE does not transmit the PUSCH in the n+4th subframe, but transmits the PUSCH at the next retransmission timing (ie, the n+12th subframe). In this case, when calculating a coding rate for transmitting UCI on PUSCH, the UE calculates different coding rates according to _{different N SRS values.} Of course, rate matching for the corresponding PUSCH may also perform another operation according to the _{N SRS value.} Rate matching means matching the amount of data to be transmitted and the maximum transmission amount of an actual channel for each transmission unit time, for example, TTI.

Meanwhile, in channel-coding CQI, RI information, and HARQ-ACK information, respectively, Q' must be determined first. Q' represents the number of coded modulation symbols per layer. The coding unit may determine Q' based on a Modulation Coding Scheme (MCS) level applied to PUSCH, and may adjust coding rates for CQI, RI, and HARQ-ACK based on the Q'.

If only one transport block, for example, HARQ-ACK or RI information is transmitted on the PUSCH (ie, in the case of single layer transmission), Q' may be calculated as in Equation 1 below. .

Here, O(alpabet O) is the number of RI bits or HARQ-ACK bits. M ^PUSCH _SC is a bandwidth scheduled for PUSCH transmission in a current subframe for a transport block, and is expressed by the number of subcarriers. N ^{PUSCH-initial} _Symbol is the number of SC-FDMA symbols per subframe for initial PUSCH transmission for the same transport block. N ^{PUSCH-initial} _Symb may be calculated as in Equation 2 below.

Here, N _SRS has a value of 1 or 0. For example, if a UE configured with one UL serving cell is configured to transmit PUSCH and SRS in the same subframe for initial PUSCH transmission, or if the UE is configured to transmit PUSCH and SRS in the same subframe for initial transmission, and the UE is not configured with multiple-TAG (Timing Advance Group), or if PUSCH resource allocation for initial transmission is cell-specific SRS subframe and bandwidth configuration and even (even) Partially overlapping, if the subframe for initial transmission in the same serving cell is a UE-specific type-1 SRS subframe, or if the subframe for initial transmission in the same serving cell is UE-specific type-0 In the case of an SRS subframe and the UE is configured with multiple Timing Advance Groups (TAGs), N _SRS may be 1, and in other cases, N _SRS may be 0.

In Equation 1 again, M ^{PUSCH-initial} _sc , C , and K _r may be obtained from an initial PDCCH (or enhanced-PDCCH (EPDCCH)) for the same transport block. If there is no initial PDCCH (or EDPCCH) of downlink control information (DCI) format 0/4 for the same transport block, M ^{PUSCH-initial} _sc , C , and K _r may be determined according to the following. For example, M ^{PUSCH-initial} _sc , C , and K _r are the most recent semi-persistent scheduling assigned PDCCH (or EPDCCH) when the same transport block is semi-persistent scheduled. ) can be determined from As another example, M ^{PUSCH-initial} _sc , C, and K _r may be determined from a random access response for the same transport block when the PUSCH is initiated by a random access response grant.

In terms of PUSCH rate matching, for example, corresponding REs are for reference signal transmission, SC-FDMA symbol configured for SRS transmission when the UE is configured with one cell, and M-TAG is not configured for the UE in the same subframe When SRS is transmitted, the last SC-FDMA symbol in one subframe, if PUSCH transmission partially or completely overlaps with the cell-specific SRS bandwidth, the last SC-FDMA symbol of the subframe in which the cell-specific SRS is configured, UE on the same serving cell -SC-FDMA symbol reserved for possible SRS transmission in a specific aperiodic SRS subframe and an SC-FDMA symbol reserved for possible SRS transmission in a UE-specific periodic SRS subframe on the same serving cell for which an M-TAG is configured for the UE PUSCH is allocated using REs except for .

Referring back to FIG. 4 , transmission of a PUSCH indicated by a previously received uplink grant on a measurement gap in DL spectrum/subframes in which one serving cell is configured and SRS transmission indicated through intra-cell RRC signaling are the same subframes. In the case in which the non-adaptive retransmission operation is applied, the PUSCH may be retransmitted at the next retransmission timing (ie, the n+12th timing) without HARQ-ACK feedback. At this time, if the terminal in which one uplink cell is configured is configured to transmit an initial PUSCH and SRS in the same subframe, NSRS=1 is assumed in the next retransmission PUSCH, and if UCI transmission is performed in the next retransmission subframe If it occurs simultaneously in the frame, a UCI code rate operation is performed to map (eg piggyback) the corresponding UCI (HARQ-ACK, RI, CQI) on the PUSCH.

On the other hand, in order for a UE configured for D2D discovery to receive discovery on different PLMNs (Inter-PLMN) or on different carriers (Inter-carrier), a carrier frequency other than the carrier frequency used by the serving PLMN is monitored. You may need to In the present invention, such a section is defined as a “monitoring section”. On the other hand, when D2D signal reception due to the monitoring period and PUSCH transmission due to the previous uplink grant are simultaneously performed, serious self-interference may occur, so it is more stable to not allow uplink transmission at this time. May lead the implementation of the terminal. Therefore, in the present invention, it is assumed that D2D signal reception takes precedence over uplink transmission in such a case.

5 and 6, a D2D terminal connected to a PLMN adjacent to the terminal receiving the first carrier from the first base station (eMB1) belonging to the serving PLMN from n+3rd subframe to n+6th subframe When it is set as a monitoring period for a D2D signal (eg, a discovery signal for inter-terminal discovery) of ) When an uplink grant indicating PUSCH transmission is received, the uplink grant is processed, but the PUSCH may not be transmitted in the n+4th subframe of the first carrier indicated for D2D signal reception. In addition, the UE may transmit the PUSCH at the next retransmission timing (ie, the n+12th subframe) without HARQ feedback through non-adaptive retransmission of the PUSCH that has not been transmitted. However, the serving base station may not know information about the monitoring period of the terminal. This is because, basically, cooperation between PLMNs is difficult. In addition, this is because only the corresponding inter-PLMN discovery UE can acquire the corresponding resource information on a carrier of another PLMN through initial cell search. Of course, in order to overcome this limitation, a terminal capable of performing cooperation between PLMNs or discovering between PLMNs in advance acquires the corresponding resource information on a carrier of another PLMN through initial cell search, and then reports it to the serving PLMN. It may be possible for the serving PLMN to obtain information about the D2D discovery resource of another PLMN. Therefore, in this situation, that is, regardless of whether the serving PLMN has acquired the discovery information of another PLMN, an uplink grant has been previously indicated to the UE from the serving base station (serving PLMN) and the next retransmission for it (if retransmission is necessary) The PUSCH may be transmitted at timing (ie, the n+12th subframe). At this time, the base station and the terminal may have different assumptions about the transmission rate of the UCI and the PUSCH rate matching. For example, the UE has M-TAG configured for one or more uplink cells (UL CA) for PUSCH transmission, the initial PUSCH and the type 0 SRS (periodic SRS) are the same subframe on the same serving cell, n In the +4th subframe, although the SRS is not actually transmitted, the SRS is configured to be transmitted. In this situation, assuming the UCI coding rate of the serving base station, the serving PLMN in the subframe in which the type 0 SRS subframe is configured is the same subframe (n+4th subframe). _{It is assumed that N SRS} = 1 for the retransmission PUSCH in the frame and decoded by calculating the UCI coding rate and rate matching. On the other hand, in the UCI coding rate and rate matching on the retransmission of the inter-PLMN discovery terminal, since the PUSCH and the SRS were not transmitted for inter-PLMN discovery monitoring on the n + 4 th subframe, N _SRS = 0 is assumed when retransmitting the PUSCH transmission, and UCI coding rate and rate matching are calculated and transmitted.

Therefore, in the n + 12th subframe, the base station receives UCI on PUSCH retransmission of the terminal assuming a different UCI coding rate, and UCI that does not match the number of UCI symbols known by the base station is transmitted from the terminal UCI decoding may fail. The reason that it is difficult to implement the base station to perform blind decoding for both NSRS=0 or 1 in preparation for this situation is that there is no information on the actual monitoring period, so the base station has to perform the above-described blind decoding on all uplink subframes. A problem arises. This may cause unnecessary operation of the base station, which may greatly increase the complexity.

In order to solve this problem, in the present invention, if the UE configured with one or more uplink cells is configured to transmit the first PUSCH and SRS in the subframe of the same serving cell within the monitoring period (not actual transmission), the corresponding PUSCH In the retransmission timing for , the rate matching for the UCI coding rate calculation is always set to be performed based on _{N SRS} =0 or N _{SRS =1.} The above SRS corresponds to a UE-specific type-1 SRS subframe or a UE-specific type-0 SRS subframe, which means that the UE is configured with an M-TAG. In addition, although the above description has been described for the purpose of calculating the UCI code rate, the same operation can be described in terms of PUSCH rate matching. For example, if the UE configured with one or more uplink cells is configured to transmit the first PUSCH and SRS in the subframe of the same serving cell within the monitoring period (not actual transmission), in the retransmission timing for the corresponding PUSCH, the corresponding Rate matching for the retransmission PUSCH always allocates a PUSCH on the last SC-FDMA symbol (N _SRS = 0) or not (N _SRS = 1).

Although it is assumed that the serving cell (or serving PLMN) does not know the information about the monitoring period, there may be situations in which it can be known by other signaling or a report of the UE. However, even in this case, in the above situation, the UCI coding rate calculation on the retransmission PUSCH and rate matching for the retransmission PUSCH may be set to always be performed based on _{N SRS} =0 or N _SRS=1. This is to prevent the above problems from occurring due to the implementation of the scheduler and other assumptions.

Therefore, the terminal performing discovery between the serving base station and the PLMN through this method uses the same information about the coding rate (the number of UCI symbols) for the UCI transmitted during retransmission through the assumption proposed in the environment shown in FIGS. 5 and 6 . Therefore, it prevents unnecessary complexity increase and resource waste (possibility of not using the last SC-FDMA symbol) in the UCI decoding operation on the base station, and effectively utilizes uplink resources accordingly to improve the uplink performance of the entire system. can

In the retransmission timing for the corresponding PUSCH as described above, a method of setting the UCI coding rate calculation and rate matching for the corresponding retransmission PUSCH to always _{be performed based on N SRS} =0 or N _SRS =1 is as follows.

If only one transport block is transmitted on the PUSCH and HARQ-ACK or RI is transmitted together (ie, in the case of single layer transmission), Q' may be calculated as shown in Equation 3 below.

Here, O(alpabet O) is the number of RI bits or HARQ-ACK bits. M ^PUSCH _SC is a bandwidth scheduled for PUSCH transmission in a current subframe for a transport block, and is expressed by the number of subcarriers. N ^{PUSCH-initial} _Symbol is the number of SC-FDMA symbols per subframe for initial PUSCH transmission for the same transport block. N ^{PUSCH-initial} _Symb may be calculated as in Equation 3 below.

Here, N _SRS has a value of 1 or 0. For example, if a UE configured to be transmitted in one or more uplink cells transmits PUSCH and SRS in the same subframe for initial transmission, or if PUSCH resource allocation for initial transmission is cell-specific SRS subframe and Bandwidth configuration and even partially overlap, if the subframe for initial transmission is a UE-specific Type-1 SRS subframe, or if the subframe for initial transmission is UE-specific If it is a Type-0 SRS subframe and the UE is configured with multiple Timing Advance Groups (TAGs), N _SRS may be 1, and in other cases, N _SRS may be 0.

In Equation 3 again, M ^{PUSCH-initial} _sc , C , and K _r may be obtained from an initial PDCCH (or enhanced-PDCCH (EPDCCH)) for the same transport block. If there is no initial PDCCH (or EDPCCH) of downlink control information (DCI) format 0 for the same transport block, M ^{PUSCH-initial} _sc , C , and K _r may be determined according to the following. For example, M ^{PUSCH-initial} _sc , C , and K _r are the most recent semi-persistent scheduling assigned PDCCH (or EPDCCH) when the same transport block is semi-persistent scheduled. ) can be determined from As another example, M ^{PUSCH-initial} _sc , C, and K _r may be determined from a random access response for the same transport block when the PUSCH is initiated by a random access response grant.

7 is a flowchart illustrating operations of a base station and a D2D receiving terminal according to an embodiment of the present invention.

Referring to FIG. 7 , the base station may transmit configuration information for D2D discovery and communication to the terminal in the cell (S710). The D2D configuration information may be transmitted to the UE for D2D discovery or D2D data transmission through, for example, a System Information Block (SIB) or dedicated RRC signaling. The information on the D2D resource pool may include information on the D2D signal monitoring period (monitoring resource information).

For example, the monitoring resource information may include information on a period for monitoring D2D signals of D2D terminals connected to a network of a single operator. Alternatively, information on a period for monitoring D2D signals of D2D terminals accessing the network of the single operator and information on a period of monitoring D2D signals of D2D terminals accessing a network of another operator may be included.

Meanwhile, the base station may transmit an uplink grant instructing transmission of the PUSCH to the terminal (S720).

Upon receiving the uplink grant, the terminal checks monitoring resource information (information on resources to be monitored by the terminal for D2D communication) (S730). If the period indicated to transmit the PUSCH and SRS overlaps with the resource (subframe) to be monitored, PUSCH and SRS are not transmitted in the corresponding period.

When the period indicated to transmit the PUSCH and SRS is included in the resource to be monitored and UCI transmission also occurs in the retransmission PUSCH subframe, the UCI coding rate for the retransmission PUSCH is calculated based on the proposed assumption, and the PUSCH rate Matching may be performed (S740). The UCI coding rate operation and a PUSCH rate matching is performed based on the value of N is set _SRS, wherein the _SRS N has a value of 0 or 1.

When the UCI coding rate calculation and PUSCH rate matching are performed in step S740, the UE transmits the PUSCH including the UCI to the base station (S750).

8 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 8 , a wireless communication system supporting inter-terminal communication according to the present invention includes a terminal 800 and a base station (or cluster head, 850 ).

The terminal 800 includes a processor 805 , a radio frequency (RF) unit 810 , and a memory 815 . The memory 815 is connected to the processor 805 and stores various information for driving the processor 805 . The RF unit 810 is connected to the processor 805 to transmit and/or receive a radio signal. For example, the RF unit 810 may receive from the base station 850 the D2D configuration information posted herein and an uplink grant indicating PUSCH transmission. Also, the RF unit 810 may transmit the PUSCH to the base station 850 at the timing indicated by the uplink grant or the retransmission timing.

The memory 815 stores D2D configuration information according to the present specification, resource pool information for the second transmission mode, information on a monitoring period for receiving a D2D signal, and the like, and according to the request of the processor 805 , the processor 805 . ) can be provided with the above information.

The processor 805 implements the functions, processes and/or methods proposed herein. Specifically, the processor 805 causes all steps according to FIG. 3 to be performed. For example, the processor 805 may include a monitoring unit 806 , a PUSCH configuration unit 807 , and a transmission timing determining unit 808 .

The monitoring unit 806 monitors the D2D signal during the monitoring period set based on the information on the monitoring period for receiving the D2D signal. Then, it is determined whether an uplink grant indicating PUSCH transmission is received in the monitoring period.

The coding rate calculating unit 807 calculates the UCI coding rate if the period for which PUSCH transmission is indicated is not included in the monitoring period.

The rate matching unit 808 performs PUSCH rate matching.

Therefore, according to the present invention, since only D2D signal reception is performed during the monitoring period, self-interference due to PUSCH transmission does not occur.

Meanwhile, the base station 850 includes a radio frequency (RF) unit 855 , a processor 860 , and a memory 865 . The memory 1065 is connected to the processor 860 and stores various information for driving the processor 860 . The RF unit 855 is connected to the processor 860 to transmit and/or receive a radio signal. The processor 860 implements the functions, processes and/or methods proposed herein. In the above-described embodiment, the operation of the base station 850 may be implemented by the processor 860 . The processor 860 generates the D2D configuration information posted herein, configures an uplink grant indicating PUSCH transmission, and processes the PUSCH received from the UE.

To this end, the processor 860 includes a D2D configuration information generation unit 861 , a UL grant configuration unit 862 , and a PUSCH processing unit 863 . The D2D configuration information generated by the D2D configuration information generator 861 may include information on the D2D resource pool for the second transmission mode. The information on the D2D resource pool may include information on the D2D signal monitoring period (monitoring resource information).

The monitoring resource information includes only information on a period for monitoring D2D signals of D2D terminals connected to a network of a single operator, or in a period for monitoring D2D signals of D2D terminals connected to a network of a single operator It may include information about the period for monitoring D2D signals of D2D terminals connected to networks of other operators and information about the period.

The UL grant configuration unit 862 configures an uplink grant indicating PUSCH transmission. The RF unit 855 transmits the uplink grant configured in the UL grant configuration unit 862 to the terminal 800 . Upon receiving the uplink grant, the terminal 800 transmits the PUSCH and the SRS at a timing indicated by the uplink grant or at a retransmission timing based on the monitoring resource information. Then, the PUSCH processing unit 863 processes the PUSCH received through the RF unit 855 .

The processor may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits, and/or data processing devices. Memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and/or other storage devices. The RF unit may include a baseband circuit for processing a radio signal. When the present embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) that performs the above-described function. A module may be stored in a memory and executed by a processor. The memory may be internal or external to the processor, and may be coupled to the processor by various well-known means.

In the exemplary system described above, the methods are described on the basis of a flowchart as a series of steps or blocks, however, the present invention is not limited to the order of steps, and some steps may occur in a different order or concurrent with other steps as described above. can In addition, those skilled in the art will understand that the steps shown in the flowchart are not exhaustive and that other steps may be included or that one or more steps in the flowchart may be deleted without affecting the scope of the present invention.

The above-described embodiments include examples of various aspects. It is not possible to describe every possible combination for representing the various aspects, but one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, it is intended that the present invention cover all other substitutions, modifications and variations falling within the scope of the following claims.

Claims (12)

A method for transmitting an uplink signal by a device in a wireless communication system, the method comprising:
Receiving configuration information (configuration info) including information on a monitoring section for monitoring a device-to-device (D2D) communication signal from the serving base station; and
Receiving an uplink grant indicating transmission of a physical uplink shared channel (PUSCH) from the serving base station; and
Comprising the step of confirming the uplink grant,
When the uplink grant indicates transmission of the PUSCH in the monitoring interval, the PUSCH transmission is not performed in the monitoring interval, but is performed at the next PUSCH transmission timing indicated by the uplink grant. Link signal transmission method.
The method of claim 1,
The setting information includes information on a first monitoring period for monitoring a D2D communication signal of a device camped on to the serving base station, and a second monitoring period for monitoring a D2D communication signal of a device not connected to the serving base station Uplink signal transmission method comprising the information on the monitoring period.
The method of claim 1,
The configuration information further includes information about a monitoring period for monitoring a D2D communication signal for a carrier different from a carrier used by the serving base station, the uplink signal transmission method.
According to claim 1, wherein the PUSCH transmission,
Uplink control information (Uplink Control Information) is piggybacked and transmitted to the PUSCH,
The coding rate calculation and rate matching for the uplink control information are performed based on the next PUSCH transmission timing, and the coding rate calculation and the rate matching are performed based on a fixed variable (NSRS) value related to whether SRS is transmitted. A method for transmitting an uplink signal.
According to claim 1,
The setting information is
An uplink signal transmission method, characterized in that it is received from a serving base station through a system information block.
The method of claim 1,
The D2D communication signal is
An uplink signal transmission method, characterized in that it is a discovery signal for device-to-device discovery.

An apparatus for performing uplink transmission in a wireless communication system, comprising:
transceiver;
one or more processors; and
a memory in which instructions are stored;
including,
the one or more processors
by the instruction stored in the memory.
Receives configuration information including information on a monitoring section for monitoring a device-to-device (D2D) communication signal from a serving base station through the transceiver, and
Receiving an uplink grant indicating transmission of a physical uplink shared channel (PUSCH) from the serving base station through the transceiver,
Check the uplink grant,
When the uplink grant indicates transmission of the PUSCH in the monitoring interval, the PUSCH transmission is not performed in the monitoring interval, but is performed at the next PUSCH transmission timing indicated by the uplink grant. A device that transmits link signals.
8. The method of claim 7,
The setting information includes information on a first monitoring period for monitoring a D2D communication signal of a device camped on the serving base station, and a second monitoring period for a D2D communication signal of a device not connected to the serving base station An apparatus for transmitting an uplink signal, comprising information on a monitoring interval.
8. The method of claim 7,
The configuration information further includes information on a monitoring period for monitoring a D2D communication signal for a carrier different from a carrier used by the serving base station, the apparatus for transmitting an uplink signal.
The method of claim 7, wherein the PUSCH transmission comprises:
Uplink control information (Uplink Control Information) is piggybacked and transmitted to the PUSCH,
Coding rate calculation and rate matching for the uplink control information are performed based on the next PUSCH transmission timing,
The apparatus for transmitting an uplink signal, wherein the coding rate calculation and the rate matching are performed based on a fixed variable (NSRS) value regarding whether to transmit SRS.

8. The method of claim 7,
The setting information is
An apparatus for transmitting an uplink signal, which is received from a serving base station through a system information block.
8. The method of claim 7,
The D2D communication signal is
A device for transmitting an uplink signal, characterized in that it is a discovery signal for device-to-device discovery.

Images