Method and apparatus for wireless communication taking into account collisions during device-to-device transmissions

Abstract

Wireless communication method carried out by a user terminal device (UE1 to UE5; 20), wherein the method comprises the following: a receiving (S100) of a first control signal from a first user terminal via a first control channel and of a second control signal from a second user terminal via a second control channel; an estimation (S200; S200') of interference in a first data channel corresponding to the first control signal or the first control channel based on the first and second control signals; a reception (S300) of a first data signal from the first user terminal device via the first data channel; and a processing (S400) of the received first data signal based on a result of the estimation, wherein the first data channel includes an initial transmission (TX0) and at least one retransmission (rTX1, rTX2, rTX3) from the first user terminal, and wherein the processing of the received first data signal involves a selective combining (S400') of the initial transmission (TX0) and the retransmission (rTX1, rTX2, rTX3) based on the estimated interference in the first data channel.

Description

BACKGROUND

[0001] Methods and devices consistent with the exemplary embodiment of the inventive concept relate to wireless communication, and more specifically to wireless communication that takes into account collisions during device-to-device (D2D) transmissions.

[0002] In a wireless communication system, communication from a base station to an end device or terminal can be referred to as a downlink (DL), and communication from an end device to a base station can be referred to as an uplink (UL). In addition to DL and UL, communication from one end device to another in a wireless communication system can be referred to as a sidelink (SL). If two or more end devices generate downlink-to-downlink (D2D) transmissions over an SL, interference can occur in these D2D transmissions. Such interference can cause problems in an end device receiving D2D transmissions, and consequently, the efficiency of the corresponding SL can degrade.Therefore, a method for efficiently processing D2D transmissions in which interference occurs is needed in an end device, as well as a method for reducing interference in D2D transmissions.

[0003] WO 2017 / 026970 A1 discloses methods and devices that enable high-data-rate relay operation using the D2D air interface, including user equipment (UE) for sending and receiving data via a sidelink interface under the control of an Evolved Node B (eNB), wherein the UE comprises: a receive circuit for receiving a reference signal on a sidelink interface; a control circuit for determining one or more sidelink quality indicators based on the received reference signal; and a transmit circuit for sending the determined sidelink quality indicators to the eNB.

[0004] US 2019 / 0007974 A1 discloses a vehicle-to-everything (V2X) communication system and a communication method within the V2X communication system. The method comprises: selecting a control channel from a control channel resource pool on a first V2X device; transmitting sidelink control information (SCI) to a second V2X device on the selected control channel; monitoring an SCI acknowledgment resource pool (SCI-ACK) for an SCI acknowledgment indicator (SCI-ACK-IND) corresponding to the transmitted SCI on the first V2X device; and transmitting data to the second V2X device in a data resource pool according to the SCI in response to receiving a positive SCI-ACK-IND corresponding to the transmitted SCI.

[0005] US 2015 / 0215903 A1 discloses systems, methods, and devices for managing interference caused by D2D communication. A wireless transmit-receive unit (WTRU) may include a processor. The processor may be configured to perform one or more of the following functions: The processor may determine to send information using device-to-device transmission over a resource pool from a plurality of resource pools. Each resource pool may be associated with a range of reference signal receive power (RSRP) values. The processor may determine an RSRP measurement of a cell connected to the WTRU. Based on the cell's RSRP measurement, the processor may select a resource pool from the plurality of resource pools. The cell's RSRP measurement may fall within the range of RSRP values ​​associated with the selected resource pool.The processor can send the information using the selected resource pool.

[0006] US 2018 / 0206211 A1 discloses a method by which a transmitting terminal in a wireless communication system transmits a signal using device-to-device communication. The method specifically comprises the following steps: dividing a plurality of resource units into clean units and dirty units; selecting at least one of the clean units as the transmission resource if the number of clean units is greater than or equal to a first threshold; selecting at least one of the dirty units as the transmission resource if the number of clean units is less than the first threshold; and transmitting a device-to-device communication signal using the selected transmission resource, wherein the transmission resource selected from the dirty units is determined based on the transmission power of the device-to-device communication signal.

[0007] US 2019 / 0075547 A1 concerns a method by which a Vehicle-to-Everything (V2X) terminal transmits data in a wireless communication system, comprising the following steps: excluding first subframes expected to be transmitted by terminals other than the terminal itself from a plurality of subframes; excluding second subframes whose measured energy is a first threshold or higher from the plurality of subframes from which the first subframes were excluded; and transmitting data in at least a subset of the plurality of subframes from which the first subframes and the second subframes were excluded. SUMMARY

[0008] The exemplary embodiments of the inventive concept provide a method and a device for wireless communication, as set out in the claims, to improve the efficiency of communication between user terminal devices, such as device-to-device (D2D) communication in a wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Exemplary embodiments of the inventive concept will be more clearly understood from the following detailed description together with the accompanying drawings, in which: Fig. 1 a block diagram of a wireless communication system comprising several pieces of user equipment and a base station according to an exemplary embodiment; Fig. 2 a flowchart of a wireless communication method according to an exemplary embodiment; Fig. Figure 3 illustrates an example of sidelink control information (SCI) contained in a physical sidelink control channel (PSCCH) according to an exemplary embodiment; Fig. 4 An example of a PSCCH and a PSSCH according to an exemplary embodiment is illustrated; Fig. 5 resource pools of sidelinks illustrated according to an exemplary embodiment; Fig. 6 is a flowchart of a wireless communication method according to an exemplary embodiment; Fig. 7A a flowchart of an example of operation S200 of the Fig. 6 according to an exemplary embodiment; Fig. 7B an example of operation S200' of the Fig. 7A illustrated according to an exemplary embodiment; Fig. 8A a flowchart of an example of operation S244 of the Fig. 7A according to an exemplary embodiment; Fig. 8B an example of operation 244a of the Fig. 8A illustrated according to an exemplary embodiment; Fig. 9A a flowchart of an example of operation S244 of the Fig. 7a according to an exemplary embodiment; Fig. 9B an example of operation S244b of the Fig. 9A illustrated according to an exemplary embodiment; Fig. 10 a flowchart of an example of the operation S244 of the Fig. 7A according to an exemplary embodiment; Fig. 11A a flowchart of an example of operation S244 of the Fig. 7A according to an exemplary embodiment; Fig. 11B illustrates an example of a transmission block of a PSSCH according to an exemplary embodiment; Fig. 12. A flowchart of examples of operations of the Fig. 6 according to an exemplary embodiment; Fig. 13 a flowchart of an example of the operation S400' of the Fig. 12 according to an exemplary embodiment; Fig. 14A Pseudocode illustrates an example of the S420 operation of the Fig. 13 according to an exemplary embodiment; Fig. 14B is a table which shows examples of combinations according to the pseudocode of the Fig. 14A illustrated according to an exemplary embodiment; Fig. 15 a flowchart of a wireless communication method according to an exemplary embodiment; Fig. 16 a flowchart of an example of the S600 operation of the Fig. 15 according to an exemplary embodiment; Fig. 17 a flowchart of an example of the operation S640 of the Fig. 16 according to an exemplary embodiment; and Fig. 18 is an exemplary block diagram of a wireless communication device according to an exemplary embodiment. DETAILED DESCRIPTION OF EXAMPLE EXECUTIONS

[0010] Fig. Figure 1 is a block diagram of a wireless communication system 10, which comprises several user equipment (UE) components and a base station (BS) 12 according to an exemplary embodiment. As a non-limiting example, the wireless communication system 10 may be a Long Term Evolution (LTE) system, a Code Division Multiple Access (CDMA) system, a Global System for Mobile Communication (GSM) system, a Wireless Local Area Network (WLAN) system, or any other wireless communication system. Hereinafter, the wireless communication system 10 is primarily described as an LTE system; however, one or more embodiments of the inventive concept are not limited thereto. The term UE may be used interchangeably with a term such as a user terminal, a mobile station, a mobile device, etc.

[0011] In general, BS 12 can be a fixed station that communicates with a UE and / or another BS, and when BS 12 communicates with the UE and / or the other BS, it can exchange data and control information with the UE and / or the other BS. For example, BS 12 can be referred to as a Node B, an evolved-Node B (eNB), a sector, a location, a base transceiver system, an access point (AP), a relay node, a remote radio head (RRH), a radio unit (RU), a small cell, or the like.In the present description, BS 12 or a cell in a broad sense can be understood as a function or area covered by a Base Station Controller (BSC) in CDMA, a Node-B in WCDMA, an eNB or a sector (location) in LTE, and can include a megacell, a macrocell, a microcell, a picocell, a femtocell, as well as various coverage areas, for example, coverage areas of a relay node, an RRH, an RU, and a small cell.

[0012] User equipment (UE1) through user equipment (UE5) refers to wireless communication devices, whether stationary or portable, that are capable of receiving and transmitting data and / or control information to and from the BS 12 by communicating with it. For example, user equipment (UE1) through user equipment (UE5) can be referred to as terminal equipment, mobile station (MS), mobile terminal (MT), user terminal (UT), subscriber station (SS), wireless device, handheld device, or similar.

[0013] A wireless communication network under the first user equipment (UE1) to the fifth user equipment (UE5) and the BS 12 can support communication between users by allowing the sharing of available network resources. For example, information can be transmitted over a wireless communication network using various multiple access methods, such as CDMA, Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA.

[0014] As in Fig. As illustrated in Figure 1, the first user equipment UE1 and the BS 12 can communicate with each other via an uplink (UL) and a downlink (DL). In a wireless system, for example, an LTE system and an LTE-Advanced system, the UL and the DL can transmit control information via control channels, such as a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator Channel (PCFICH), a Physical Hybrid ARQ Indicator Channel (PHICH), a Physical Uplink Control Channel (PUCCH), an Enhanced Physical Downlink Control Channel (EPDCCH), etc., or they can transmit data via data channels, such as a Physical Downlink Shared Channel (PDSCH), a Physical Uplink Shared Channel (PUSCH), etc.

[0015] The first user equipment UE1 and the second user equipment UE2 can communicate with each other via a sidelink (SL). In a third-generation partnership project (3GPP = 3 rdThe Generation Partnership Project (GPS)-LTE standardization of Proximity-based Service (Prose) communication as Device-to-Device (D2D) communication was completed in version 12. Likewise, the standardization of Enhanced D2D (eD2D) was completed in version 13, and the standardization of Vehicle-to-Vehicle (V2V) and Vehicle-to-Everything (V2X) communication using a SL was completed in version 14. Referring to Fig. 1. The first user equipment UE1 through the fifth user equipment UE5 can communicate with each other via SLs. For example, the first user equipment UE1 can communicate with the second user equipment UE2 and the third user equipment UE3 via an SL 12 and an SL 13, respectively, if the first user equipment UE1 through the third user equipment UE3 are contained in a first group G1. The SL can transmit a control signal containing control information over a control channel such as a Physical Sidelink Control Channel (PSCCH) (or Scheduling Assignment (SA)), and can transmit a data signal containing data over a data channel such as a Physical Sidelink Shared Channel (PSSCH) (or a D2D data channel). In this description, receiving / transmitting signals over the PSCCH or the PSSCH can be expressed as "transmitting / receiving the PSCCH or the PSSCH".

[0016] In D2D communications, since each of the first user equipment UE1 and the second user equipment UE2 can independently generate a D2D transmission, interference can occur. For example, a D2D transmission from the second user equipment UE2 to the first user equipment UE1 via SL 12 can interfere with a D2D transmission from the third user equipment UE3, which is included in the first group G1, to the first user equipment UE1 via SL 13. Similarly, as shown by a dashed line SL 15 in Fig. As indicated in diagram 1, the D2D transmission from the second user equipment UE2 to the first user equipment UE1 via SL 12 can be interfered with by a D2D transmission from the fifth user equipment UE5 to the fourth user equipment UE4 via SL 45 if the fifth user equipment UE5 is included in a second group G2. In the LTE system, D2D communications define a Mode 1, in which radio resources are determined by BS 12, and a Mode 2, in which radio resources are determined by each of the first user equipment UE1 through the fifth user equipment UE5. In Mode 1, interference in D2D transmissions can be relatively weak but cannot be avoided. In Mode 2, interference can frequently occur due to independent resource allocation by the first user equipment UE1 through the fifth user equipment UE5.Unlike in Mode 1 and Mode 2, D2D communications in the LTE system can additionally define Mode 3 and Mode 4 in V2X.

[0017] As will be described below, in some exemplary embodiments, a user entity (UE) can predict or anticipate interference in a PSSCH based on at least one PSCCH received by at least one UE, and can process the PSSCH based on the estimated interference. Consequently, the data reception rate in the PSSCH can increase. Likewise, in some exemplary embodiments, a UE can schedule a PSSCH to be transmitted to another UE in such a way as to reduce interference with another PSSCH based on at least one PSCCH received by at least one UE. Consequently, the data reception rate in the PSSCH and the efficiency of D2D communication in a system such as the wireless communication system 10 can increase.It is hereby assumed that a wireless communication method according to exemplary embodiments is implemented by the first user equipment UE1 of the . Fig. 1 is carried out, however it is noted that other exemplary embodiments may be carried out by any device which supports D2D communication.

[0018] Fig. Figure 2 is a flowchart of a wireless communication method according to an exemplary embodiment. For example, the wireless communication method of Fig. 2 through the first user equipment UE1 of the Fig. 1 shall be carried out, and herein below the wireless communication method of Fig. 2 with reference to Fig. 1. will be described.

[0019] Referring to Fig. 2. In operation S21, at least one piece of sidelink control information (SCI) can be received in a PSCCH. The SCI received in the PSCCH can contain information about the timing of a PSSCH to be received after the PSCCH. For example, the SCI can determine a set of subframes and a set of resource blocks associated with the PSSCH. Likewise, the SCI can contain a group identifier (ID) that identifies a group (for example, the first group G1 of the Fig. 1) indicates which user equipment (UE) is capable of transmitting modulation and coding scheme (MCS) information and the PSCCH. Consequently, the first user equipment (UE1) from the SCI can identify a resource configuration of the PSSCH, which is to be received after receiving the PSCCH; that is, resource blocks containing data from the UE that transmitted the PSSCH in a PSSCH resource pool. The SCI is described in detail below with reference to the Fig. 3 and Fig. 4 will be described.

[0020] In Operation S22, interference in a PSSCH can be estimated. For example, if the first user equipment UE1 receives two pieces of SCI in PSSCH resource configurations from the second user equipment UE2 and the third user equipment UE3 in Operation S21, the first user equipment UE1 can estimate interference between PSSCHs from the second user equipment UE2 and the third user equipment UE3. That is, since the first user equipment UE can detect PSSCH resource configurations from the two pieces of SCI from the second user equipment UE2 and the third user equipment UE3, collision blocks that collide with each other can be detected from the resource blocks containing data. The first user equipment UE1 can estimate interference in data transmissions based on these collision blocks.

[0021] Operation S23 can process a PSSCH. In some exemplary embodiments, the first user equipment UE1 can process a received PSSCH based on the interference estimated in Operation 22. For example, the first user equipment UE1 can perform a Hybrid Automatic Repeat Request (HARQ) combination operation based on the estimated interference. In some exemplary embodiments, the first user equipment UE1 can schedule a PSSCH to be transmitted based on the interference estimated in Operation S22. For example, the first user equipment UE1 can schedule a PSSCH to be transmitted based on the estimated interference and can transmit a PSCCH containing the SCI and the PSSCH according to the scheduled PSSCH.

[0022] Fig. Figure 3 illustrates an example of an SCI contained in a PSCCH according to an exemplary embodiment. In detail, it illustrates Fig. 3 a “SCI format ()” which is used in Mode 1 and Mode 2 of D2D communication.

[0023] Referring to Fig. 3. The SCI in the PSCCH can contain fields, for example, fields F01 to F06, to hold control information for D2D communication. The first field, F01, can be a "frequency hopping flag," indicating whether frequency hopping is applied to a PSSCH. The second field, F02, can be a resource block assignment and a "hopping resource allocation," providing information about resource blocks allocated to the PSSCH. This field can also contain additional information about a frequency hopping configuration if frequency hopping is being used. The third field, F03, can be a "time resource structure," indicating subframes used in the PSSCH. The fourth field, F04, can be a "modulation and encoding scheme," indicating the modulation and encoding applied to the PSSCH.The fifth field, F05, can be a "timing pre-indication," used in Mode 1 of D2D communication, and displays a time selection or timing adjustment value for a receiver. The sixth field, F06, can be a "group target ID," indicating a group that has a UE transmitting the PSSCH.

[0024] A PSSCH resource configuration can be defined by the first three fields F01 to F03 from the SCI fields described above, that is, the first six fields F01 to F06. In other words, the UE can detect a subsequent PSSCH resource configuration based on the first three fields F01 to F03 contained in an SCI received by a PSCCH. Examples of PSSCH resource configurations defined in the SCI are given with reference to Fig. 4 will be described.

[0025] A UE that supports D2D communication can always monitor a PSCCH resource pool. A UE wishing to receive a D2D transmission can attempt to receive all PSCCH resources contained in the PSCCH resource pool and can extract a group ID from the sixth field F06 of a SCI in the successfully received PSCCH. If the extracted group ID is associated with the UE (for example, if the extracted group ID is the same as a group ID of the UE), the UE can process resource blocks of a subsequent PSSCH according to the first three fields F01 to F03, as specified in the fourth field F04.If the extracted group ID is not linked to the UE (for example, if the extracted group ID is different from the group ID of the UE), the UE cannot monitor a subsequent PSSCH resource pool that corresponds to a PSCCH resource pool.

[0026] In some exemplary embodiments, the UE can detect a PSSCH resource configuration that corresponds to a PSCCH relevant for the UE's group ID. For example, to estimate interference in a D2D transmission, the first user equipment UE1 of the Fig. 1. A corresponding PSSCH resource configuration can be detected from the second user equipment UE2 and the third user equipment UE3, which are contained in the same group as a group of the UE (i.e., the first group G1), and from the fifth user equipment UE5, which is contained in a different group from the group of the UE (i.e., the second group G2). In other words, regardless of the sixth field F06 of the SCI, the UE can detect the PSSCH resource configuration from the first to third fields F01 to F03. Likewise, as below with reference to Fig. As will be described in section 10, in some exemplary embodiments the UE uses an MCS, which is indicated by the fourth field F04 of an SCI, to estimate interference in a D2D transmission.

[0027] Fig. Figure 4 illustrates an example of a PSCCH and a PSSCH according to an exemplary embodiment. Fig. Figure 5 illustrates resource pools of SLs according to an exemplary embodiment. In detail, it illustrates Fig. 4 an example of a PSCCH and a PSSCH in mode 2 of a D2D communication, and Fig. 5 illustrates an example in which some pieces from UE of the Fig. 1. Attempt simultaneous D2D communication over SLs that exhibit SL 12 and SL 13. As above, with reference to Fig. As described in section 3, a PSCCH can define a PSSCH resource configuration. The PSSCH resource configuration of the Fig. 4 is merely an example defined by the PSCCH, and it should be noted that the PSSCH resource configuration is defined by a PSCCH in a different way from the way of Fig. 4 can be defined. The exemplary embodiments of the are described below. Fig. 4 and Fig. 5 with reference to Fig. 3 will be described.

[0028] Referring to Fig. 4. The PSCCH and PSSCH can be transferred within a specific period saPeriod. The PSCCH can be transferred from a starting point of the period saPeriod, and the PSSCH can be transferred after a specific time period (i.e., an offset) has elapsed from the starting point of the period saPeriod. A resource pool RP, into which the PSCCH and PSSCH are transferred, can denote a set of resources allocated to a SL transfer and can contain subframes and resource blocks within the subframes.

[0029] The subframes used in the PSSCH can be determined by a bitmap expressed as a binary value. For example, as in Fig. Figure 4 illustrates that in a "subframeBitmap" which has a binary value, "1" indicates a used subframe, and "0" can indicate a subframe that is not used. In the PSSCH, the "subframeBitmap" can occur repeatedly, and consequently, a structure of used subframes can be repeated. In some exemplary embodiments, the third field F03 of the SCI can be Fig. 3. Have a Time Resource Structure (TRP) index I_TRP, and a “subframeBitmap” can be determined by the TRP index I_TRP.

[0030] Within the subframes used, resource blocks containing data can be identified accordingly, based on whether a physical resource block (PRB) is assigned. For example, as in Fig. As illustrated in Figure 4, a used band is determined by a "startPRB" and a "numPRB". This means that the "startPRB" can indicate the first used resource block, and the "numPRB" can indicate the number of used resource blocks. Consequently, resource blocks contained within a band defined by the "startPRB" and the "numPRB" can be populated with data within resource blocks contained in the used subframes. In some exemplary embodiments, the "startPRB" and the "numPRB" can be determined by the second field F02 of the SCI. Fig. 3 will be determined. Although Fig. While only one band is illustrated in section 4, two or more bands can be used. For example, an “endPRB” can be additionally represented by the second field F02 of the SCI. Fig. 3 are determined, and a band which is separated from the band of the Fig. 4 is removed, can additionally be used by the “endPRB” and the “numPRB”.

[0031] Referring to Fig. 5. Interference can occur in D2D transmissions. For example, as in Fig. As illustrated in Figure 5, a PSSCH transmitted by the second user equipment UE2 via SL 12 can interfere with a PSSCH transmitted by the third user equipment UE via SL 13. The interference in the PSSCHs can depend on a PSSCH resource configuration defined by a PSCCH of SL 12 and a PSSCH resource configuration defined by a PSCCH of SL 13. For example, resource blocks according to the PSSCH resource configuration of SL 12 can collide with resource blocks according to the PSSCH resource configuration of SL 13, and this collision can cause interference in the PSSCHs. Therefore, UE can estimate the interference in the PSSCHs based on the PSSCH resource configurations detected by the PSCCHs.As described below with reference to the drawings, the estimated interference can be used to process a PSSCH received by the UE, or it can be used to schedule a PSSCH to be transmitted to another UE. The collision between the resource blocks of the PSSCHs is described with reference to... Fig. 7B etc. will be described.

[0032] Fig. Figure 6 is a flowchart of a wireless communication method according to an exemplary embodiment. It illustrates in detail... Fig. 6. A method in which a UE processes a received PSSCH based on interference in PSSCHs. For example, the wireless communication method of Fig. 6 through the first user equipment UE1 of the Fig. 1. The first user equipment UE1 can process a PSSCH received by the second user equipment UE2. The wireless communication method of the following is described below. Fig. 6 with reference to Fig. 1. will be described.

[0033] Referring to Fig. 6. In Operation S100, multiple pieces of SCI can be received in PSCCHs. For example, the first user equipment UE1 can receive pieces of SCI in a PSCCH from the second user equipment UE2 and a PSCCH from the third user equipment UE3, which are contained in the first group G1, as well as a PSCCH from the fifth user equipment UE5, which is contained in the second group G2.

[0034] In Operation S200, interference in the PSSCHs can be estimated. For example, the first user equipment UE1 can detect PSSCH resource configurations corresponding to pieces of SCI based on the pieces of SCI received in Operation S100, and can estimate the interference in the PSSCHs based on the detected PSSCH resource configurations. Examples relating to Operation S200 are given with reference to Fig. 7A and Fig. 7B etc. will be described.

[0035] In operation S300, a PSSCH can be received. For example, the first user equipment UE1 can receive a PSSCH from the second user equipment UE2. In some exemplary embodiments, the first user equipment UE1 can perform operation S300 before operation S200, or it can perform operation S200 and operation S300 in parallel.

[0036] In Operation S400, an received PSSCH can be processed based on the estimated interference. For example, the first user equipment UE1 can selectively process subframes and / or resource blocks contained in the PSSCH based on the estimated interference. A detailed description of Operation S400 is provided with reference to Fig. 12 etc. are planned.

[0037] Fig. 7A is a flowchart of an example of operation S200 of the Fig. 6 according to an exemplary embodiment. Fig. 7B illustrates an example of the S200 operation. Fig. 7A according to an exemplary embodiment. As above with reference to Fig. As described in section 6, operation S200' can be used. Fig. 7A the interference in the PSSCH is estimated. Examples of the following are given below. Fig. 7A and Fig. 7B with reference to the Fig. 1 and Fig. 6 will be described.

[0038] Referring to Fig. 7A allows operation S220 to detect a collision between resource blocks of the PSSCHs. For example, the first user equipment UE1 can detect a collision between resource blocks of PSSCHs, which are transmitted by the second user equipment UE2 and the third user equipment UE3, respectively. As in Fig. As illustrated in 7B, in SL 12 and SL 13 of the second user equipment UE2 and the third user equipment UE3 the PSSCHs can have resource blocks which collide in (k+1)th and (k+2)th subframes, i.e. collision resource blocks.

[0039] In Operation S240, interference or non-interference in a PSSCH can be determined based on a detected collision. For example, the first user equipment UE1 can determine whether interference occurs in a PSSCH received by the second user equipment UE2 via SL 12. As in Fig. As illustrated in 7A, operation S240 can include operations S242, S244, S246 and S248.

[0040] Operation 242 can be used to check whether a collision is detected in a PSSCH. For example, if a collision is detected in the PSSCH by the second user equipment UE2, Operation S244 can be performed subsequently; however, if a collision is not detected, Operation S248 can be used to determine that interference does not occur in the PSSCH by the second user equipment UE2.

[0041] Operation 244 can determine whether interference occurs in the PSSCH. For example, the first user equipment UE1 can determine whether interference occurs in the PSSCH of the second user equipment UE2 based on information about the PSSCH from the second user equipment UE2. A detailed description of Operation 244 will be given later with reference to the Fig. 8A to 11B are provided by describing examples for determining interference in units of subframes. If it is determined that interference occurs in the PSSCH from the second user equipment UE2, then in operation S246 it can be determined that interference occurs in the PSSCH from the second user equipment UE2. However, if it is determined that interference does not occur in the PSSCH from the second user equipment UE2, then in operation S248 it can be determined that interference does not occur in the PSSCH from the second user equipment UE2. As below with reference to Fig. As described in 12 etc., the PSSCH can be processed according to the interference or non-interference in the PSSCH.

[0042] Fig. 8A is a flowchart of an example of operation S244 of the Fig. 7A according to an exemplary embodiment. Fig. 8B illustrates an example of operation S244a of the Fig. 8A according to an exemplary embodiment. As above with reference to Fig. As described in section 7A, whether interference occurs in a PSSCH can be determined in operation S244a and can be determined based on the number of collision resource blocks in operation S244a. As described in Fig. As illustrated in 8A, operation S244a can have operations S81 and S82.

[0043] In Operation S81, the number of collision resource blocks (cRB) can be obtained. For example, as in Fig. As illustrated in 8B, the PSSCH of SL 12 can have three collisions in each of a k-th subframe and a (k+3)-th subframe, and can have two collisions in a (k+2)-th subframe.

[0044] In operation S82, the result of a function "f(cRB)", which has the number of collision resource blocks cRB as a factor, is compared to a first reference value REF1. For example, "f(cRB)" can be proportional to the number of collision resource blocks cRB. If "f(cRB)" is larger than the first reference value REF1, it is determined that interference occurs in the PSSCH, and therefore operation S246 can be performed. Fig. 7A will be carried out below. On the other hand, if the “f(cRB)” is not greater than the first reference value REF1, it is determined that interference does not occur in the PSSCH, and therefore operation S248 of the Fig. 7A will be carried out below.

[0045] Referring to Fig. In some exemplary embodiments, 8B allows the number of collision resource blocks cRB to be compared with the first reference value REF1. For example, if the first reference value REF1 is equal to 2, the k-th subframe and the (k+3)-th subframe can be determined to have interference, whereas the (k+2)-th subframe can be determined to not have interference.

[0046] In some exemplary embodiments, a ratio of the number of collision resource blocks cRB to the total number of resource blocks nRB can be compared with the first reference value REF1. For example, as in Fig. Figure 8B illustrates that “cRB / nRB” is calculated in each subframe, and if the first reference value REF1 is equal to 0.5, the k-th subframe and the (k+3)-th subframe can be determined to have interference, whereas the (k+2)-th subframe can be determined to not have interference.

[0047] In some exemplary embodiments, a weight proportional to the number of resource block collisions can be reflected to the "f(cRB)". For example, as in Fig. As illustrated in Figure 8B, a value (i.e., nCollision), which is the largest of the collisions of the collision resource blocks contained in the subframes, is extracted and can be compared to the first reference value REF1. The k-th subframe and the (k+3)-th subframe have the same number of collision resource blocks. The collision resource blocks contained in the (k+3)-th subframe can have a greater number of collisions than the collision resource blocks contained in the k-th subframe. Consequently, due to weighting, the result of a function corresponding to the (k+3)-th subframe can be greater than the result of a function corresponding to the k-th subframe. Operations to determine whether interference occurs in a PSSCH based on the number of collision resource blocks cRB are merely examples.If interference in a PSSCH, estimated based on the number of collision resource blocks cRB, is stronger, then any function f will have a larger value.

[0048] Fig. 9A is a flowchart of an example of operation S244 of the Fig. 7A according to an exemplary embodiment. Fig. 9B illustrates an example of operation S244b of the Fig. 9A according to an exemplary embodiment. In operation S244b of the Fig. 9A, the occurrence of interference in a PSSCH can be determined based on the channel quality of a D2D communication. As in Fig. As illustrated in 9A, operation 244b can include operations S91 and S92.

[0049] In Operation S91, channel qualities such as qCHs can be achieved. For example, as in Fig. Figure 9B illustrates that the first user equipment UE1 can achieve a channel quality qCH12 of SL 12 and a channel quality qCH13 of SL 13. In some exemplary embodiments, the channel qualities qCHs of a PSCCH can be obtained, for example, from a k'-th subframe of the PSCCH. The channel qualities qCHs can be values ​​determined based on various factors. In some exemplary embodiments, as shown in Fig. As illustrated in Figure 9B, each of the channel qualities qCHs can be a signal power of the PSCCH, and in some exemplary embodiments, each of the channel qualities qCHs can be defined based on a channel's signal-to-noise ratio (SNR), a channel's signal-to-interference + noise ratio (SINR), or a combination thereof. Since a strong signal can be received in an SL with a high channel quality, a strong signal in an SL that is to be received can increase a receive ratio. A strong signal in another SL can cause interference, and therefore a receive ratio can decrease.

[0050] In operation S92, the result of a function "g(qCHs)", which has the channel qualities qCHs as factors, can be compared with a second reference value REF2. For example, the "g(qCHs)" can be inversely proportional to the channel quality of one SL and proportional to the channel quality of another SL. If the "g(qCHs)" is larger than the second reference value REF2, it can be determined that the interference in the PSSCH is significant, and therefore operation S246 can be performed. Fig. 7A will be carried out below. In contrast, if the “g(qCHs)” is not greater than the second reference value REF2, it is determined that no interference occurs in the PSSCH, and therefore operation S248 of the Fig. 7A will be carried out.

[0051] Referring to Fig. 9B, if the first user equipment UE1 wishes to receive the PSSCH of SL 12, a function g' can be defined as a ratio of the channel quality qCH13 of SL 13 to the channel quality qCH12 of SL 12. Accordingly, the function g' can be defined as a ratio of the signal power of the PSSCH from the second user equipment UE2 to the signal power of the PSSCH from the third user equipment UE3. Therefore, at the k-th subframe of the PSSCH of SL 12, the number of collision resource blocks is only 1. However, if a value of "g'(qCHs)" is greater than the second reference value REF2, the k-th subframe can be determined as an impaired subframe.

[0052] Fig. 10 is a flowchart of an example of the operation S244 of the Fig. 7A according to an exemplary embodiment. In operation S244c of the Fig. 10. It can be determined whether interference occurs in a PSSCH based on an MCS extracted from SCI. As in Fig. As illustrated in 10, operation S244c can have operations S101 and S102.

[0053] In Operation 101, an MCS index I_MCS can be obtained from SCI. As above, with reference to Fig. As described in section 3, the SCI can have a fourth field, F04, which displays an MCS schema of a PSSCH, and the first user equipment, UE1, can extract the MCS index I_MCS from this fourth field. The MCS index I_MCS can indicate an index corresponding to a modulation scheme and a coding scheme in a predefined MCS table. Referring to the MCS table, the first user equipment, UE1, can identify a modulation scheme and a coding scheme that correspond to the obtained MCS index I_MCS. A high MCS index I_MCS in the MCS table can correspond to a higher modulation order.

[0054] In operation S102, the MCS index I_MCS can be compared to a third reference value REF3. For example, since a signal modulated with a high modulation order is highly susceptible to interference, if a relatively high MCS index is used in a PSSCH where a collision is detected, it can be determined that interference is occurring in the PSSCH. If the MCS index I_MCS is greater than the third reference value REF3, it is determined that interference is occurring in the PSSCH, and therefore operation S246 can be used. Fig. 7A will be performed subsequently. However, if the MCS index I_MCS is not greater than the third reference value REF3, it is determined that no interference occurs in the PSSCH, and therefore operation S248 of the Fig. 7A will be carried out below.

[0055] Fig. 11A is a flowchart of an example of operation S244 of the Fig. 7A according to an exemplary embodiment. Fig. Figure 11B illustrates an example of a transfer block (TB) of a PSSCH according to an exemplary embodiment. In operation S244d of the Fig. 11A can be used to determine whether interference occurs in a PSSCH based on a redundancy version (RV). As in Fig. As illustrated in 11A, operation S244d can have operations S111 and S112.

[0056] In operation S111, a reversal of pregnancy (RV) can be achieved. For example, as in Fig. Figure 11B illustrates how the first user equipment UE1 extracts a TB from a PSSCH, which contains subframes and resource blocks. In D2D communication (or SL communication), since a receiver does not provide feedback regarding a reception for a transmitter, the transmitter can generate an initial transmission and three retransmissions, and the receiver can combine the initial transmission and the retransmissions. In the present embodiment, combining the received transmissions, for example, the initial transmission and the retransmissions, can be combining resource blocks that are contained in each of the received transmissions. In some exemplary embodiments, the transmission can have different RVs.This means that, based on incremental redundancy (IR), where retransmitted bits do not match originally transmitted bits, the received initial transmission and the received retransmissions can be selectively combined. For example, as in . Fig. As illustrated in Figure 11B, a redundancy version 0 (RV0) is applied to an initial transmission TX0, and an RV2, an RV3, and an RV1 can subsequently be applied to the first to third retransmissions rTX1 to rTX3, respectively. When RVs are applied to four consecutive transmissions—that is, the initial transmission TX0 and the first to third retransmissions rTX1 to rTX3—in a fixed order, the acquisition of an RV can be considered as the acquisition of ordinal numbers of the transmissions TX0 and rTX1 to rTX3.

[0057] Operation S112 allows the determination of the necessity of the RV (Reference Resource Block). For example, in D2D communication, different RVs may have the same MCS (Multiple Content Set) but correspond to different sections of encoded data. Consequently, each of the received transmissions TX0 and rTX1 to rTX3, which have different RVs, will have collision resource blocks. However, if the received transmissions TX0 and rTX1 to rTX3 correspond to sections of data necessary for decoding, the transmissions TX0 and rTX1 to rTX3 can be combined.In some exemplary embodiments, the first user equipment UE1 can detect a section of data necessary for decoding, according to whether at least one previously received transmission has collided with another transmission, and an RV and the first user equipment UE1 can determine whether a currently received transmission is to be combined with another transmission, based on the occurrence of a collision between the currently received transmission and an RV. If it is determined that the received RV is necessary, operation S246 of the . Fig. 7A is subsequently carried out in such a way that a transmission can be determined as an interference transmission. In contrast, if the obtained RV is not necessary, operation S248 of the Fig. 7B subsequently carried out in such a way that the transmission can be determined to be a non-interference transmission.

[0058] The examples of Operation S244 of the Fig. 7A, which determines whether interference occurs in a PSSCH, has so far been described with reference to the Fig. Sections 8A to 11B describe this. However, it can be understood that a combination of one or more of the above examples can be used to determine the interference in the PSSCH, or that methods different from the above examples can be used.

[0059] Fig. 12 is a flowchart of examples of operations S300 and S400 of the Fig. 6 according to an exemplary embodiment. As above with reference to the Fig. As described in section 6, a PSSCH can be used in operation S300'. Fig. 12 can be received and can be based on interference in Operation S400' of the Fig. 12 will be processed.

[0060] Referring to Fig. 12. In operation S300', an initial transmission and at least one retransmission can be received in a PSSCH. For example, as above with reference to Fig. As described in section 11B, the initial transmission TX0 and the first to third retransmissions rTX1 to rTX3 are received in the PSSCH. In some exemplary embodiments, operation S200 of the Fig. 6. Interference in each of the initial transmission TX0 and the first to third retransmissions rTX1 to tTX3 can be estimated.

[0061] In Operation S400', based on an estimation of interference, the received initial transmission and at least one retransmission can be selectively combined. For example, the received initial transmission TX0 and the first to third retransmissions rTX1 to rTX3 of the Fig. 11B can be selectively combined, depending on the occurrence of interference. In some exemplary embodiments, only the transmissions in which no interference occurs can be combined, but in other exemplary embodiments, interference transmissions can also be combined, depending on conditions.

[0062] Regardless of the occurrence of interference in transmissions, if demodulation and / or decoding is performed by combining the received initial transmission TX0 and all of the received first to third retransmissions rTX1 to rTX3, the demodulation and / or decoding performance may decrease due to the combination with a transmission in which interference occurs. For example, in the example of the Fig. 7B the (k+1)th and (k+2)th subframes, which contain the collision resource blocks from the subframes received by the second user equipment UE2 via the SL 12, degrade the demodulation and / or decoding performance due to the combination.

[0063] It may not be easy to accurately estimate interference in PSSCHs based on channel quality. For example, since a demodulation reference signal (DMRS) of a PSSCH is relatively easy to determine, the probability of finding the same DMRS in PSSCHs transmitted by two or more pieces of user equipment may be relatively high. Consequently, even if a PSSCH's channel quality, such as its SINR, is high, interference in a PSSCH with a resource configuration defined by a PSCCH is not always weak. Therefore, as described above with reference to the accompanying diagrams, a PSSCH resource configuration is detected from SCI, and collisions between resource blocks of a PSSCH are detected based on the PSSCH resource configuration, thus detecting interference in the PSSCH with improved accuracy.As a result, based on the detected interference, the reception ratio can be improved by selectively combining a plurality of received transmissions.

[0064] Fig. 13 is a flowchart of an example of the operation S400' of the Fig. 12 according to an exemplary embodiment. As above with reference to Fig. As described in section 12, operation S400" can be used. Fig. 13 the initial transmission and each of the at least one subsequent transmission can be selectively combined.

[0065] Referring to Fig. 13. Operation S400 can include operations S420 and S440. In operation S420, the received transmissions are combined according to predetermined conditions. In some exemplary embodiments, only transmissions in which no interference occurs (or interference is not estimated, or non-interference transmissions) can be combined. In other exemplary embodiments, transmissions in which no interference occurs are combined, and transmissions in which interference occurs (is estimated) can be combined only if the transmission satisfies the predetermined conditions. Examples of operation S420 are given later with reference to the Fig. 14A and Fig. 14B will be described. After operation S420 has been performed, demodulation and / or decoding can be performed in operation S440.

[0066] Fig. Figure 14A illustrates a pseudocode which is an example of the S420 operation of the Fig. 13 according to an exemplary embodiment. Fig. 14B is a table which gives examples of combinations according to the pseudocode of the Fig. 14A illustrates an exemplary embodiment. As above with reference to Fig. As described in section 13, transmissions which are in accordance with the pseudocode (S420') of the Fig. 14A will be received and combined according to the predetermined conditions. In the table of Fig. 14B indicates “N” non-interference, “I” indicates interference, and groups of transmissions that are combined are shown in each case.

[0067] Referring to Fig. In line 11 to 13 of 14A, an initial transmission can be processed. The initial transmission can be considered a new transmission regardless of whether interference occurs. This means that a combination of the initial transmission with other transmissions can be used to determine whether interference occurs in the initial transmission and according to transmissions received subsequently.

[0068] Lines 14 to 22 can process a first or second retransmission. Line 15 can be used to check for the existence of a transmission in which no interference occurs before the first or second retransmission.

[0069] If such a non-interference transmission exists before the first or second retransmission, the first or second retransmission in which interference occurs cannot be combined (line 16), but the first or second retransmission in which interference does not occur can be combined (line 17). On the other hand, if a transmission in which interference does not occur does not exist before the first or second retransmission—that is, if interference occurs in all transmissions before the first or second retransmission—the first or second retransmission in which interference occurs can be combined (line 20), while the first or second retransmission in which interference does not occur can be considered a new transmission.The first or second retransmission, which is considered a new transmission, is combined with a transmission to be received subsequently, instead of a previously received transmission.

[0070] In lines 23 to 29, a third retransmission can be processed. In line 24, the existence of a transmission in which no interference occurs can be checked before the third retransmission, and if such a non-interference transmission exists, this non-interference transmission can be combined with the third retransmission (line 24). Conversely, if a transmission in which no interference occurs before the third retransmission does not exist—that is, if interference occurs in all transmissions before the third retransmission—the third retransmission in which interference occurs can be combined (line 26), while the third retransmission in which no interference occurs can be considered a new transmission.The third retransmission, which is considered a new transmission, can be decoded independently instead of being combined with previously received transmissions.

[0071] Referring to Fig. According to T14B, transmissions estimated as non-interference N can be combined, and some transmissions estimated as interference I can also be combined. For example, all third retransmissions rTX3 can be used for decoding, and if interference occurs in the initial transmission TX0 and the first and second retransmissions rTX1 and rTX2 (T15), the initial transmission TX0 and the first and second retransmissions rTX1 and rTX2 can be independently demodulated and / or decoded, and in other cases, they can be combined with at least one previously received transmission.Additionally, if interference occurs in all of the initial transmission TX0 and the first to third retransmissions rTX1 to rTX3 (T16), since it may be more advantageous to combine all of the initial transmissions TX0 and the first to third retransmissions rTX1 to rTX3 than to exclude some of the initial transmissions TX0 and the first to third retransmissions rTX1 to rTX3, all of the initial transmissions TX0 and the first to third retransmissions rTX1 to rTX3 can be combined. As described in T09 to T15 of the... Fig. According to section 14B, the first to third retransmissions rTX1 to rTX3 can be considered new transmissions and can therefore be combined in a second group, which is distinct from a first group containing the initial transmission TX0. In some exemplary embodiments, if decoding is successfully performed on transmissions that have been received, for example, if a cyclic redundancy check (CRC) is successful, a subsequently received transmission may not be processed (e.g., combined, decoded, etc.). That is, if decoding is successful in the first group of the Fig. If 14B is performed, the second group cannot be processed. According to the examples of Fig. 14A and Fig. 14B are the conditions for combining the received transmissions as follows.

[0072] Condition 1: If interference occurs in all of the preceding transmissions and the current transmission, all of the preceding transmissions are combined with the current transmission. For example, in T13 the Fig. 14B, if interference occurs in the initial transmission TX0 and the first retransmission rTX1, the received first retransmission rTX1 is combined with the received initial transmission TX0.

[0073] Condition 2: If interference occurs in all of the preceding transmissions but not in the current transmission, the current transmission is not combined with the preceding transmissions. In other words, the current transmission is excluded from being combined with the preceding transmissions. For example, in T09 of Fig. B, if interference occurs in the initial transmission TX0 but not in the first retransmission rTX1, the first retransmission rTX1 can be combined with a subsequently received transmission instead of the initial transmission TX0.

[0074] Condition 3: If no interference occurs in the current transmission, the current transmission is combined with at least one preceding transmission in which no interference occurs. For example, in T05 the Fig. 14B if interference does not occur in the initial transmission TX0 and the second retransmission rTX2, but does occur in the first retransmission rTX1, the second retransmission rTX2 can be combined with the initial transmission TX0, but the first retransmission rTX1 can be excluded from the combination.

[0075] Condition 4: The third retransmission rTX3 is combined with at least one preceding transmission in which no interference occurs. This means that in T15 and T16 of the Fig. 14B, if interference occurs in all of the initial transmission TX0 and the first and second retransmissions rTX1 and rTX2, the third retransmission rTX3, in which interference does not occur, can be decoded independently, and the third retransmission rTX3, in which interference occurs, can be combined with the initial transmission TX0 and the first and second retransmissions rTX1 and rTX2.

[0076] As a result of experiments, in a specific environment (I_MCS = 27.36 RB, SINR >25 dB, I_TRP = 2), the receive rate increases from approximately 55% to approximately 95% due to a selective combination according to the exemplary embodiments above. Additionally, as a result of experiments, when the number of colliding resource blocks increases, the receive rate due to an unconditional combination decreases rapidly; however, the receive rate is essentially maintained according to a selective combination according to the exemplary embodiments above.

[0077] In some exemplary embodiments, a combination of pseudocodes is included in a combination of an initial transmission in which no interference occurs; however, if no interference occurs in any transmission, preceding transmissions in which interference occurs can be selectively combined. The conditions which refer to the Fig. 14A and Fig. The conditions described in 14B are merely examples, and other conditions for combining transmissions in which interference occurs can be defined according to exemplary embodiments.

[0078] Fig. Figure 15 is a flowchart of a wireless communication method according to an exemplary embodiment. It illustrates in detail... Fig. 15. A wireless communication method in which a UE schedules a PSSCH based on interference in another PSSCH and transmits it. For example, the wireless communication method of Fig. 15 through the first user equipment UE1 of the Fig. 1. This is carried out, and the first user equipment UE1 can transmit a PSSCH to the second user equipment UE2 and / or the third user equipment UE3. The wireless communication method of the following is described below. Fig. 15 with reference to Fig. 1. will be described.

[0079] Referring to Fig. 15. In Operation S500, at least one piece of SCI can be received in a PSCCH. For example, the first user equipment UE1 can receive SCI in a PSCCH from at least one of the second user equipment UE3 and the third user equipment UE3, which are contained in the first group G1, and the fifth user equipment UE5, which is contained in the second group G2.

[0080] In Operation S600, SCI can be defined to reduce interference with a PSSCH. For example, the first user equipment UE1 can detect a PSSCH resource configuration that matches the received SCI, based on the SCI received in Operation S500, and can define SCI (or SCI for transmissions) used to schedule a PSSCH to be transmitted, thus reducing interference with the PSSCH that has the detected PSSCH resource configuration. An example of Operation S600 is described with reference to Fig. 16 will be described.

[0081] In Operation S700, the SCI can be transferred to a PSSCH. For example, the first user equipment UE1 can transfer the SCI defined in Operation S600 to the PSCCH. The SCI transferred to the PSSCH can have a group ID that identifies the first group.

[0082] In Operation S800, a PSSCH can be transmitted. For example, the first user equipment can transmit the PSSCH, which is scheduled according to the SCI defined in Operation S600 and transmitted in Operation S700. This means that this PSSCH can have a resource configuration defined based on the SCI transmitted in Operation S700; that is, resource blocks containing data whose location is determined based on the SCI. Since the resource configuration of the PSSCH transmitted by the first user equipment UE1 is defined to reduce interference with a PSSCH for at least one other UE, the receive rate of the PSSCH transmitted by the first user equipment UE1 can increase at a receiver.

[0083] Fig. 16 is a flowchart of an example of the S600 operation of the Fig. 15 according to an exemplary embodiment. As above with reference to Fig. As described in section 15, operation S600 is the Fig. 16 SCI defined to reduce interference with a PSSCH. The following is an example of Fig. 16 with reference to the Fig. 1 and Fig. 15 will be described.

[0084] In operation S620, a PSSCH resource pool can be captured. For example, based on the SCI, which is defined in operation S500, Fig. Upon receiving SCI 15, the first user equipment UE1 captures a PSSCH resource pool or PSSCH resource configuration, according to the received SCI. Consequently, an arrangement of resource blocks containing data can be captured from the PSSCH.

[0085] In Operation S640, a PSSCH can be scheduled. For example, the first user equipment UE1 can schedule a PSSCH to be transferred to another UE based on the PSSCH resource pool acquired in Operation S620. In some exemplary embodiments, the first user equipment UE1 can schedule a PSSCH to reduce collisions with resource blocks containing data on the acquired PSSCH resource pool. In some exemplary embodiments, based on the PSSCH resource pool, the first user equipment UE1 can schedule a PSSCH to reduce interference with resource blocks that might collide with the scheduled PSSCH. Therefore, by considering other PSSCHs, the PSSCH can be scheduled to provide an improved reception ratio. An example of Operation S640 is given with reference to Fig. 17 will be described.

[0086] Fig. 17 is a flowchart of an example of the S640 operation of the Fig. 16 according to an exemplary embodiment. As above with reference to Fig. As described in section 16, operation 640' can be performed. Fig. 17 a PSSCH which is to be transferred, must be scheduled in time, and operation S640' can include operations S642 and S644. The following is an example of Fig. 17 with reference to the Fig. 1 and Fig. 16 will be described.

[0087] In operation S642, non-collision subframes can be assigned. For example, the first user equipment UE1 can determine subframes that are not used in the captured PSSCH resource pool—that is, subframes that do not contain the resource blocks that contain the data—and can assign subframes that correspond to the captured subframes as subframes for a PSSCH to be transferred (i.e., the non-collision subframes). Consequently, resource blocks in the assigned subframes cannot collide with other resource blocks.

[0088] In Operation S644, subframe interference can be estimated. For example, the first user equipment UE1 can estimate interference with the subframes used in the captured PSSCH resource pool, that is, interference with the subframes containing the resource blocks that hold the data. Subframe interference can be estimated based on at least one factor ARG according to the exemplary embodiments described above with reference to the drawings. For example, subframe interference can be estimated based on at least one of the number of collision resource blocks cRB, the ratio cRB / nRB, the ratio of collision resource blocks cRB to the number nRB of resource blocks in the subframes, and the channel qualities qCHs, or at least two combinations thereof.

[0089] In Operation S646, collision subframes can be assigned. For example, based on the interference estimated in Operation S644, the first user equipment UE1 can assign the subframes for the PSSCH to be transmitted (i.e., collision subframes) in a sequence of subframes that predict weaker interference. Consequently, the PSSCH transmitted by the first user equipment UE1 can have reduced interference with a PSSCH with respect to another UE.

[0090] Fig. Figure 18 is an exemplary block diagram of a wireless communication device 20 according to an exemplary embodiment. As in Fig. As illustrated in Figure 18, the wireless communication device 20 can have an application-specific integrated circuit (ASIC) 21, an application-specific instruction set processor (ASIP) 23, a memory 25, a main processor 27, and a main memory 29. At least two of the ASIC 21, the ASIP 23, and the main processor 27 can communicate with each other. Likewise, at least two of the ASIC 21, the ASIP 23, the memory 25, the main processor 27, and the main memory 29 can be embedded in a single chip.

[0091] The ASIP 23 can be a custom integrated circuit for a specific purpose, may support an instruction set for only one application, and can execute instructions contained in that instruction set. The memory 25 can communicate with the ASIP 23 and can store instructions executed by the ASIP 23 as a non-temporary storage device. For example, as a non-restrictive example, the memory 25 can be any type of memory accessible by the ASIP 23. Examples of any type of memory include random-access memory (RAM), read-only memory (ROM), tapes, magnetic disks, optical disks, volatile memory, non-volatile memory, and a combination thereof.

[0092] The main processor 27 can control the wireless communication device 20 by executing instructions. For example, the main processor 27 can control the ASIC 21 and the ASIP 23 and can process data received over a wireless communication network or user input to the wireless communication device 20. The main memory 29 can communicate with the main processor 27 and can store instructions executed by the main processor 27 as a non-temporary storage device. For example, the main memory 29 can be any type of memory accessible by the main processor 27, such as RAM, ROM, tapes, magnetic disks, optical disks, volatile memory, non-volatile memory, and a combination thereof.

[0093] The wireless communication method according to one or more embodiments of the inventive concept can be implemented by at least one of the components which are located in the wireless communication device of the Fig.18 are contained within. In some embodiments, at least one of the wireless communication operations can be implemented by the instructions stored in memory 25. In some embodiments, at least one of the wireless communication operations can be implemented as a hardware block designated by a logic synthesis, etc., and can be contained in ASIC 21. In some embodiments, at least one of the wireless communication operations can be implemented as instructions stored in main memory 29, and when the main processor 27 implements the instructions stored in main memory 29, at least one wireless communication operation can be performed.

Claims

[1] Wireless communication method carried out by a user terminal device (UE1 to UE5; 20), wherein the method comprises: a receiving (S100) of a first control signal from a first user terminal via a first control channel and of a second control signal from a second user terminal via a second control channel; an estimation (S200; S200') of interference in a first data channel corresponding to the first control signal or the first control channel based on the first and second control signals; a reception (S300) of a first data signal from the first user terminal device via the first data channel; and a processing (S400) of the received first data signal based on a result of the estimation, wherein the first data channel includes an initial transmission (TX0) and at least one retransmission (rTX1, rTX2, rTX3) from the first user terminal, and wherein the processing of the received first data signal involves a selective combining (S400') of the initial transmission (TX0) and the retransmission (rTX1, rTX2, rTX3) based on the estimated interference in the first data channel. [2] Wireless communication method according to claim 1, wherein the estimation (S200; S200') of the interference comprises: a detection (S220) of a collision of resource blocks of the first data channel with resource blocks of a second data channel with the second user terminal based on the first and second control signals, wherein the second data channel is used to receive a second data signal from the second user terminal; and a determination (S240) of the interference in the first data channel based on the detected collision. [3] Wireless communication method according to claim 2, wherein determining (S240) the interference comprises determining (S244a) the interference based on a number of collision resource blocks among the resource blocks of the first data channel which collide with the resource blocks of the second data channel. [4] Wireless communication method according to claim 3, wherein determining (S244a) the interference comprises determining the interference based on a ratio of the number of collision resource blocks to a number of resource blocks of the first data channel. [5] Wireless communication method according to claim 2, wherein determining (S240) the interference comprises determining the interference based on a weighting which is proportional to a number of collisions at the collision resource blocks. [6] Wireless communication method according to claim 2, wherein the estimation (S200) of the interference comprises obtaining (S91) a channel quality of the first control channel or the first data channel with the first user terminal and a channel quality of the second control channel or the second data channel with the second user terminal, and wherein the determination (S240) of the interference comprises determining (S92) the interference further based on the channel qualities of the first control channel or the first data channel and the second control channel or the second data channel. [7] Wireless communication method according to any one of claims 2 to 6, wherein the first control channel and the second control channel are both a physical sidelink control channel (PSCCH), and the first data channel and the second data channel are both a physically shared sidelink channel (PSSCH) used in device-to-device (D2D) communication. [8] Wireless communication method according to claim 6, wherein obtaining (S91) the channel qualities (S91) comprises obtaining a signal power of the first user terminal and a signal power of the second user terminal, and wherein determining (S240) the interference comprises determining the interference based on a ratio of the signal power of the second user terminal to the signal power of the first user terminal. [9] Wireless communication method according to claim 2, wherein determining (S240) the interference comprises determining (S244c) the interference based on a modulation and a coding scheme index which are contained in the first control signal. [10] Wireless communication method according to claim 2, wherein determining (S240) the interference comprises determining (S244d) the interference further based on redundancy versions (RVs) of the initial transmission and the at least one retransmission. [11] Wireless communication method according to claim 1 or 2, wherein the selective combining (S400') comprises combining two or more in which interference does not occur, from the initial transmission (TX0) and the retransmission (rTX1, rTX2, rTX3). [12] Wireless communication method according to claim 1 or 2, wherein the first data channel comprises the initial transmission (TX0), a first retransmission (rTX1), a second retransmission (rTX2) and a third retransmission (rTX3) which are received sequentially, and wherein the selective combining comprises combining the initial transmission (TX0) and the retransmission further based on ordinal numbers of the first to third retransmission (rTX1, rTX2, rTX3). [13] Wireless communication method according to any one of claims 1 to 12, wherein the first control signal and the second control signal each comprise a group identifier of a group of a plurality of user terminal devices, each comprising the first user terminal device and the second user terminal device. [14] Wireless communication method according to claim 1, further comprising: based on the first and second control signals, a third control signal is generated, which is used to schedule a third data signal to be transmitted to a third user terminal in order to reduce interference in a third data channel transmitting the third data signal; and a transmission of the control signal to the third user terminal via a third control channel with the third user terminal. [15] Wireless communication method which is carried out by a user terminal device, wherein the method comprises: a obtaining (S21; S100) at least one control signal from at least one user terminal device through at least one control channel; an estimation (S22; S200) of interference in a first data channel with a first user terminal under the at least one user terminal based on the at least one control signal; and a processing (S23; S400) of a first data signal received via the first data channel, based on the estimated interference, furthermore comprising an acquisition (S300') of an initial transmission (TX0) and at least one retransmission (rTX1, rTX2, rTX3) from the first user terminal via the first data channel, wherein the processing of the first data signal comprises a selective combination (S400') of the initial transmission and the retransmission based on the estimated interference, which exhibits interference between the initial transmission and the retransmission, and a second data channel, which corresponds to a second control channel below the at least one control channel, with a second user terminal below the at least one user terminal. [16] Wireless communication method according to claim 15, wherein the acquisition (S21; S100) of the at least one control signal comprises the acquisition (S100) of a plurality of control signals which are received by a plurality of user terminal devices which have the first user terminal device, and wherein the estimation (S22; S200) of the interference comprises: a detection of a collision (S220) between resource blocks of a plurality of data channels, corresponding to the plurality of control signals, based on the plurality of control signals; and a determination (S240) of the interference based on the detected collision. [17] Wireless communication method according to claim 16, wherein the plurality of control signals each has a group identifier of a group which has different user terminal devices. [18] Wireless communication method according to claim 15, wherein the processing of the first data signal comprises: a third control signal for transmission, which is used to schedule a third data channel and is transmitted to a third user terminal in such a way as to reduce interference between the first data channel and the third data channel; and a scheduling (S640) of the third data channel based on the third control signal. [19] Device comprising a processor and a memory which is accessed by the processor and which is configured to store a plurality of instructions which are executed by the processor to carry out the wireless communication method according to any of the preceding claims.

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