Wireless terminal and method for wireless terminal

Abstract

The present invention relates to a wireless terminal and a method of the wireless terminal. A method of the wireless terminal, the method comprising: after a period corresponding to a physical side link control channel (PSCCH) period, the allocation of radio resources for data transmission continues to be valid; and performing the data transmission on a physical side link shared channel (PSSCH) without transmitting the PSCCH including the allocation information of the radio resources.

Description

[0001] This application is a divisional application of the application with PCT application number PCT / JP2016 / 002376, international application date May 16, 2016, Chinese application number 201680041216.X, and invention name “Terminal, base station and method therefor”. Technical Field

[0002] The present disclosure relates to inter-terminal direct communication (device-to-device (D2D) communication), and in particular, to allocation of radio resources for D2D communication. Background Art

[0003] The type of communication in which a wireless terminal communicates directly with other wireless terminals without passing through an infrastructure network such as a base station is called device-to-device (D2D) communication. D2D communication includes at least one of direct communication and direct discovery. In some implementations, a plurality of wireless terminals supporting D2D communication form a D2D communication group autonomously or under the control of a network, and communicate with other wireless terminals in the formed D2D communication group.

[0004] Proximity-based services (ProSe) specified in 3GPP Release 12 are one example of D2D communication (see, e.g., Non-Patent Document 1). ProSe direct discovery is performed by a wireless terminal capable of performing ProSe (i.e., a ProSe-enabled user equipment (UE)) discovering another ProSe-enabled UE simply by using the capabilities of the radio communication technology of the two UEs (e.g., Evolved Universal Terrestrial Radio Access (E-UTRA) technology). ProSe direct discovery may be performed by three or more ProSe-enabled UEs.

[0005] ProSe direct communication enables a communication path to be established between two or more ProSe-enabled UEs present in a direct communication range after performing a ProSe direct discovery procedure. In other words, ProSe direct communication enables a ProSe-enabled UE to communicate directly with other ProSe-enabled UEs without passing through a public land mobile network (PLMN) including a base station (eNodeB (eNB)). ProSe direct communication may be performed by using a radio communication technology also used to access the base station (eNB) (i.e., E-UTRA technology) or by using a wireless local area network (WLAN) radio technology (i.e., IEEE 802.11 radio technology).

[0006] In 3GPP Release 12, the radio link between wireless terminals used for direct communication or direct discovery is called a side link (for example, refer to Section 14 in Non-Patent Document 2). The side link uses the Long Term Evolution (LTE) frame structure defined for uplink and downlink, and uses a subset of uplink resources in the frequency domain and time domain. The wireless terminal (ie, UE) performs side link transmission by using the same single carrier FDMA (frequency division multiple access) (SC-FDMA) as used in the uplink.

[0007] In 3GPP Release 12 ProSe, a radio access network (e.g., Evolved Universal Terrestrial Radio Access Network (E-UTRAN)) performs radio resource allocation to a UE for sidelink transmission. A UE that has been permitted to perform sidelink communication through the ProSe function performs ProSe direct discovery or ProSe direct communication by using radio resources allocated by a radio access network node (e.g., an eNB (eNB)).

[0008] As for ProSe direct communication, two resource allocation modes are defined, namely, scheduled resource allocation and autonomous resource selection. Scheduled resource allocation and autonomous resource selection are respectively referred to as "sidelink transmission mode 1" and "sidelink transmission mode 2" (see Section 14 in Non-Patent Document 2).

[0009] In resource allocation for ProSe direct communication scheduling, when a UE desires to perform sidelink transmission, the UE requests the eNB to perform radio resource allocation for sidelink transmission, and the eNB allocates resources and data for sidelink control to the UE. Specifically, the UE sends a scheduling request for requesting uplink (UL) data transmission resources (i.e., uplink shared channel (UL-SCH) resources) to the eNB, and then sends a sidelink buffer status report (sidelink BSR) to the eNB by using the UL data transmission resources allocated by an uplink grant (UL grant). The eNB determines the sidelink transmission resources to be allocated to the UE based on the sidelink BSR, and sends a sidelink grant (SL grant) to the UE.

[0010] The SL grant is defined as downlink control information (DCI) format 5. The SL grant (i.e., DCI format 5) contains contents such as resources for PSCCH, resource block assignments and hopping allocations, and a time resource pattern index. The resources for PSCCH indicate the radio resources used for the sidelink control channel (i.e., the physical sidelink control channel (PSCCH)). Resource block assignments and hopping allocations are used to determine the frequency resources, i.e., a set of subcarriers (resource blocks), for sending a sidelink data channel (i.e., the physical sidelink shared channel (PSSCH)) for sidelink data transmission. The time resource pattern index is used to determine the time resources, i.e., a set of subframes, for transmitting the PSSCH. Note that, strictly speaking, a resource block means a time-frequency resource in LTE and LTE-Advanced, and is a unit of resources specified by consecutive OFDM (or SC-FDMA) symbols in the time domain and by consecutive subcarriers in the frequency domain. In the case of a normal cyclic prefix, a resource block includes 12 consecutive OFDM (or SC-FDMA) symbols in the time domain and 12 subcarriers in the frequency domain. That is, the resource block assignment and hopping allocation and the time resource pattern index specify the resource block for sending PSSCH. The UE (i.e., the sidelink transmitting terminal) determines the PSCCH resources and PSSCH resources according to the SL grant.

[0011] On the other hand, in autonomous resource selection for ProSe direct communication, the UE autonomously selects resources for sidelink control (i.e., PSCCH) and data (i.e., PSSCH) from a resource pool set by the eNB. The eNB may allocate a resource pool for autonomous resource selection to the UE in a system information block (SIB) 18. The eNB may allocate a resource pool for autonomous resource selection to a UE in radio resource control (RRC)_CONNECTED through dedicated RRC signaling. This resource pool may also be available when the UE is in RRC_IDLE.

[0012] When direct transmission is performed on the side link, the UE on the transmitting side (i.e., the UE transmitting D2D) (hereinafter referred to as the transmitting terminal) transmits scheduling assignment information by using a portion of the radio resources (i.e., the resource pool) used for the side link control channel (i.e., the PSCCH). The scheduling assignment information is also referred to as side link control information (SCI) format 0. The scheduling assignment information includes contents such as resource block assignment and hopping allocation, time resource pattern index, and modulation and coding scheme (MCS). In the case of the above-mentioned scheduled resource allocation, the resource block assignment and hopping allocation and the time resource pattern index (i.e., SCI format 0) indicated by the scheduling assignment follow the resource block assignment and hopping allocation and the time resource pattern index (i.e., DCI format 5) indicated by the SL grant received from the eNB.

[0013] The transmitting terminal sends data on the PSSCH by using radio resources according to the scheduling assignment information. The UE on the receiving side (i.e., the UE receiving D2D) (hereinafter referred to as the receiving terminal) receives the scheduling assignment information from the transmitting terminal on the PSCCH, and receives data on the PSSCH according to the received scheduling assignment information. Note that the term "transmitting terminal" only focuses on the transmitting operation of the wireless terminal and does not mean a radio terminal dedicated to transmission. Similarly, the term "receiving terminal" is a statement used to express the receiving operation of the wireless terminal and does not mean a wireless terminal dedicated to reception. That is, the transmitting terminal is capable of performing a receiving operation, and the receiving terminal is capable of performing a sending operation.

[0014] Hereinafter, the sidelink control period, the resource pool for PSCCH and the resource pool for PSSCH are described. These are needed to determine the radio resources (i.e., subframes and resource blocks) used to send PSCCH and the radio resources used to send PSSCH. As described before, PSCCH is a sidelink physical channel for sending sidelink control information (SCI) such as scheduling assignment information. On the other hand, PSSCH is a sidelink physical channel for user data transmission (direct transmission).

[0015] The sidelink control period is a scheduling period for the sidelink (see Figure 1 ). The sidelink control period is also called the PSCCH period. The transmitting terminal sends scheduling assignment information (i.e., SCI format 0) in each sidelink control period. In 3GPP version 12, the sidelink control period is 40ms, 60ms, 70ms, 80ms, 120ms, 140ms, 160ms, 240ms, 280ms, or 320ms. In other words, the sidelink control period is 40 subframes, 60 subframes, 70 subframes, 80 subframes, 120 subframes, 140 subframes, 160 subframes, 240 subframes, 280 subframes, or 320 subframes.

[0016] Therefore, the transmitting terminal notifies the receiving terminal of the allocation of PSSCH resources in each side link control period (i.e., every 40 ms or longer). However, it is noted that the allocation of PSSCH resources is specified in units of 6, 7 or 8 subframes (6, 7 or 8 ms) by using a time resource pattern index. Therefore, in one side link control period, the PSSCH resource allocation is periodically used in a period of 6, 7 or 8 subframes.

[0017] In one side link control period, the transmitting terminal transmits scheduling assignment information (i.e., SCI format 0) twice in two subframes among LPSCCH subframes included in the resource pool (subframe pool) of PSCCH. Two transmissions are performed in two different resource blocks among MPSCCH_RPRB resource blocks included in the resource pool (resource block pool) of PSCCH.

[0018] The resource pool of PSCCH for the UE is set by the eNB via broadcast (SIB 18) or dedicated RRC signaling. In the sidelink control period, the resource pool of PSCCH is determined by L PSCCH subframes and M PSCCH _ RP RB frequency domain resource blocks.

[0019] In the following, refer to Figure 2 and Figure 3 The method for specifying a PSCCH resource pool is described below. The PSCCH resource pool consists of a subframe pool and a resource block pool. Figure 2 shows the subframe pool of PSCCH, Figure 3 A resource block pool for PSCCH is shown.

[0020] The eNB specifies the length (P) of the sidelink control period (PSCCH period), the subframe bitmap of the PSCCH and its length (N') in order to identify the subframe pool used for the PSCCH. The length (N') of the subframe bitmap is 4, 8, 12, 16, 30, 40 or 42 bits. The N' subframes corresponding to the subframe bitmap are as follows: Figure 2 The first N' subframes in the sidelink control period shown in . The subframe bitmap indicates that the subframes corresponding to the bits set to "0" are not used for PSCCH transmission and the subframes corresponding to the bits set to "1" are available for PSCCH transmission. Therefore, the number of subframes included in the PSCCH resource pool in one sidelink control period (LPSCCH) is equal to the number of bits set to "1" in the subframe bitmap. The subframes included in the PSCCH resource pool (i.e., subframe pool) can be represented as follows:

[0021]

[0022] On the other hand, Figure 3As shown, the eNB specifies the index (S1) of the starting physical resource block (PRB), the index (S2) of the ending PRB, and the number (M) of PRBs to identify the resource block pool for the PSCCH. The resource block pool contains M PRBs where the PRB index q of each is equal to or greater than the starting index (S1) and less than S1 + M (i.e., S1 <= q < S1 + M) and M PRBs where the PRB index q of each is greater than S2 - M and equal to or less than the ending index (S2) (i.e., S2 - M < q <= S2), that is, the total number of PRBs is 2M. Thus, the eNB can include two PRB clusters (each containing M PRBs) in the resource block pool for the PSCCH.

[0023] Hereinafter, a method for specifying the PSCCH resource pool is described. In the case of scheduled resource allocation (i.e., sidelink transmission mode 1), the eNB specifies the subframe pool for the PSSCH via SIB 18 or dedicated signaling (RRC signaling). The sidelink control period (PSCCH period) associated with the PSCCH resource configuration is also associated with the PSSCH resource configuration. The UE determines the PSSCH resource pool composed of the subframe pool as follows. Specifically, as Figure 2 shown, in the sidelink control period (PSCCH period), subframes each having an index equal to or greater than l PSCCH PSCCH-1 + 1 belong to the subframe pool of the PSSCH.

[0024] On the other hand, in the case of autonomous resource selection (i.e., sidelink transmission mode 2), the eNB specifies the subframe pool and the resource block pool for the PSSCH via SIB 18 or dedicated signaling (RRC signaling). The eNB specifies an offset (O2), a subframe bitmap, and its length (N B ) to specify the subframe pool.

[0025] The offset (O2) indicates the subframe index j begin relative to the first subframe in the sidelink control period (i.e., the PSCCH period). In this example, it is assumed that the number of subframes each having a subframe index equal to or greater than j begin + O2 in the PSCCH period is N'.

[0026] The length (N B ) of the subframe bitmap is 4, 8, 12, 16, 30, 40, or 42 bits. The subframe bitmap indicates that subframes corresponding to bits set to "0" are not used for PSSCH transmission and subframes corresponding to bits set to "1" can be used for PSSCH transmission. Note that, under normal circumstances, the length (NB) of the subframe bitmap is less than the number of subframes each having an index equal to or greater than j beginThe total number of subframes with subframe indexes of +02 (N'). Therefore, the UE uses the following formula to determine the bitmaps b0, b1, b2, ..., b N’-1 .

[0027]

[0028] Among them, a0, a1, a2, ..., a N_B-1 is of length N indicated by the eNB in ​​the PSSCH configuration B If b j =1, then subframe l j Belongs to the subframe pool used for PSSCH.

[0029] The resource block pool of PSSCH in the case of autonomous resource selection (sidelink transmission mode 2) is specified in the same way as the resource block pool of PSCCH. Specifically, in order to identify the resource block pool of PSSCH, the eNB specifies the index of the starting physical resource block (PRB) (S1), the index of the ending PRB (S2), and the number of PRBs (M) through the PSSCH resource configuration.

[0030] Reference List

[0031] Non-patent literature

[0032] Non-patent document 1: 3GPP TS23.303V12.4.0 (2015-03), "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Proximity-based services (ProSe); Stage 2 (Release 12)", March 2015

[0033] Non-patent document 2: 3GPP TS 36.213 V12.5.0 (2015-03), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures (Release 12)”, March 2015 Summary of the invention

[0034] Technical issues

[0035] As mentioned above, the sidelink transmission of 3GPP Release 12 uses a subset of uplink resources in the frequency domain and the time domain. Therefore, during the sidelink transmission, the UE cannot receive the sidelink signal sent from other UEs in the subframe. This is because the signal sent from the UE is received by the UE itself as a high-power interference signal.

[0036] Therefore, in the subframe in which the UE is sending scheduling assignment information (i.e., SCI format 0) on the PSCCH, it cannot receive scheduling assignment information (SCI format 0) sent from other UEs. If the UE cannot receive scheduling assignment information in a specific sidelink control period (PSCCH period), it cannot perform data reception (PSSCH reception) in the sidelink control period associated with the scheduling assignment information. It should be noted that the number of subframes included in the part of the radio resources of the PSCCH (i.e., the subframe pool of the PSCCH) in which the scheduling assignment information is sent is less than the number of subframes included in the part of the radio resources (i.e., the subframe pool of the PSSCCH) used for data transmission (PSSCH transmission). Therefore, the following situation is unlikely to occur: because the UE is sending scheduling assignment information (i.e., SCI format 0), the UE cannot receive scheduling assignment information from other UEs.

[0037] One of the purposes achieved by the embodiments disclosed herein is to provide devices, methods and programs that help reduce the reception failure of scheduling assignment information (SCI format 0) that is sent in a radio resource area for control (e.g., a resource pool for PSCCH) within a periodic D2D control period (e.g., a side link control period) and that specifies D2D transmission resources (e.g., subframes and resource blocks for PSCCH transmission).

[0038] Solution to the problem

[0039] In a first aspect, a transmitting terminal includes at least one wireless transceiver and at least one processor. The at least one processor is coupled to the at least one wireless transceiver and is configured to perform data transmission for other wireless terminals according to a periodic device-to-device (D2D) control period without passing through a base station. Each of the D2D control periods includes a first subframe pool and a second subframe pool, the first subframe pool consisting of a plurality of subframes that can be used to send D2D control information, and the second subframe pool consisting of a plurality of subframes that can be used to send data according to the D2D control information. The at least one processor is configured to send first D2D control information in one or more subframes in the first subframe pool within a first D2D control period, and to perform data transmission in one or more subframes in the second subframe pool within the first D2D control period according to the first D2D control information. The first D2D control information includes a first information element for identifying one or more subframes in the second subframe pool within the first D2D control period. The first D2D control information further includes a second information element, where the second information element indicates whether the first D2D control information is valid in at least one D2D control period occurring after the first D2D control period.

[0040] In a second aspect, a method in a transmitting terminal includes performing data transmission to a receiving terminal according to periodically occurring device-to-device (D2D) control periods without passing through a base station. Each of the D2D control periods includes a first subframe pool and a second subframe pool, the first subframe pool consisting of a plurality of subframes that can be used to transmit D2D control information, and the second subframe pool consisting of a plurality of subframes that can be used to transmit data according to the D2D control information. Performing the data transmission includes transmitting first D2D control information in one or more subframes in the first subframe pool within a first D2D control period, and performing data transmission in one or more subframes in the second subframe pool within the first D2D control period according to the first D2D control information. The first D2D control information includes a first information element for identifying one or more subframes in the second subframe pool within the first D2D control period. The first D2D control information also includes a second information element, the second information element indicating whether the first D2D control information is valid in at least one D2D control period occurring after the first D2D control period.

[0041] In a third aspect, a receiving terminal includes at least one wireless transceiver and at least one processor. The at least one processor is coupled to the at least one wireless transceiver and is configured to perform receiving data from a transmitting terminal according to a periodic device-to-device (D2D) control period without passing through a base station. Each of the D2D control periods includes a first subframe pool and a second subframe pool, the first subframe pool consisting of a plurality of subframes that can be used to send D2D control information, and the second subframe pool consisting of a plurality of subframes that can be used to receive data according to the D2D control information. The at least one processor is configured to receive first D2D control information in one or more subframes in the first subframe pool within a first D2D control period, and perform data reception in one or more subframes in the second subframe pool within the first D2D control period according to the first D2D control information. The first D2D control information includes a first information element for identifying one or more subframes in the second subframe pool within the first D2D control period. The first D2D control information further includes a second information element, where the second information element indicates whether the first D2D control information is valid in at least one D2D control period occurring after the first D2D control period.

[0042] In a fourth aspect, a method in a receiving terminal includes performing receiving data from a transmitting terminal without passing through a base station according to periodically occurring device-to-device (D2D) control periods. Each of the D2D control periods includes a first subframe pool and a second subframe pool, the first subframe pool consisting of a plurality of subframes that can be used to send D2D control information, and the second subframe pool consisting of a plurality of subframes that can be used to receive data according to the D2D control information. Performing the data reception includes receiving first D2D control information in one or more subframes in the first subframe pool within a first D2D control period, and performing data reception in one or more subframes in the second subframe pool within the first D2D control period according to the first D2D control information. The first D2D control information includes a first information element for identifying one or more subframes in the second subframe pool within the first D2D control period. The first D2D control information also includes a second information element, the second information element indicating whether the first D2D control information is valid in at least one D2D control period occurring after the first D2D control period.

[0043] In a fifth aspect, a base station includes: a wireless transceiver configured to communicate with multiple wireless terminals in a cell; and at least one processor. The at least one processor is configured to control data transmission. The data transmission is from a first wireless terminal to a second wireless terminal according to a device-to-device (D2D) control period that occurs periodically, without passing through the base station. Each of the D2D control periods includes a first subframe pool and a second subframe pool, the first subframe pool consisting of a plurality of subframes that can be used to send D2D control information, and the second subframe pool consisting of a plurality of subframes that can be used to send data according to the D2D control information. The at least one processor is configured to send a D2D permission message to the first wireless terminal, the D2D permission message indicating the radio resource allocation for the transmission of the D2D control information and the data transmission in the first D2D control period, and also indicating that the radio resource allocation is also valid in at least one D2D control period that occurs after the first D2D control period.

[0044] In a sixth aspect, a method in a base station includes controlling data transmission. The data transmission is from a first wireless terminal to a second wireless terminal according to a device-to-device (D2D) control period that occurs periodically, without passing through the base station. Each of the D2D control periods includes a first subframe pool and a second subframe pool, the first subframe pool consisting of a plurality of subframes that can be used to transmit D2D control information, and the second subframe pool consisting of a plurality of subframes that can be used to transmit data according to the D2D control information. The control includes sending a D2D grant message to the first wireless terminal, the D2D grant message indicating the radio resource allocation for the transmission of the D2D control information and the data transmission in the first D2D control period, and also indicating that the radio resource allocation is also valid in at least one D2D control period that occurs after the first D2D control period.

[0045] In a seventh aspect, a program comprises a set of instructions (software codes), which, when loaded into a computer, cause the computer to execute the method according to the second, fourth or sixth aspect above.

[0046] Advantageous Effects of the Invention

[0047] According to the above aspects, it is possible to provide an apparatus, method and procedure that help reduce the reception failure of scheduling assignment information (SCI format 0) that is sent in a radio resource area for control (e.g., a resource pool for PSCCH) within a periodic D2D control period (e.g., a side link control period) and that specifies D2D transmission resources (e.g., subframes and resource blocks for PSCCH transmission). BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a view showing a side link control period (PSCCH period).

[0049] Figure 2 is a view showing an example of a PSCCH subframe pool and a PSSCH subframe pool in a sidelink control period.

[0050] Figure 3 is a view showing an example of a PSCCH resource block pool in a sidelink control period.

[0051] Figure 4 is a diagram showing a configuration example of a wireless communication system according to some embodiments.

[0052] Figure 5 It is a view illustrating transmission of scheduling assignment information (PSCCH) and data (PSSCH) on a side link by a wireless terminal (transmitting terminal) according to the first embodiment.

[0053] Figure 6 is a flowchart showing an example of the operation of the wireless terminal (transmitting terminal) according to the first embodiment.

[0054] Figure 7 is a flowchart showing an example of the operation of the wireless terminal (receiving terminal) according to the first embodiment.

[0055] Figure 8 is a flowchart showing an example of the operation of the base station according to the first embodiment.

[0056] Fig. 9 is a flowchart showing an example of the operation of the wireless terminal (transmitting terminal) according to the second embodiment.

[0057] Fig.10 is a flowchart showing an example of the operation of the wireless terminal (receiving terminal) according to the second embodiment.

[0058] Fig.11 is a flowchart showing an example of the operation of the wireless terminal (transmitting terminal) according to the third embodiment.

[0059] Fig.12 is a flowchart showing an example of the operation of the base station according to the fourth embodiment.

[0060] Fig.13 is a block diagram showing a configuration example of a wireless terminal according to some embodiments.

[0061] Fig.14 is a block diagram showing a configuration example of a base station according to some embodiments. DETAILED DESCRIPTION

[0062] Hereinafter, specific embodiments will be described in detail with reference to the accompanying drawings. In the entire drawings, the same symbols are used to represent the same or corresponding elements, and for the sake of clarity, repeated descriptions are omitted when necessary.

[0063] The following embodiments will be described assuming that they are implemented to improve ProSe specified in 3GPP Release 12 (LTE-Advanced). However, the embodiments are not limited to LTE-Advanced and its improved forms, and may also be applied to D2D communications in other mobile communication networks or systems.

[0064] First embodiment

[0065] Figure 4 An example configuration of a wireless communication system according to some embodiments including this embodiment is shown. Each of the wireless terminals (UE) 1A and 1B includes at least one wireless transceiver, and is configured to perform cellular communication (101 or 102) with a base station (eNB) 2 and to perform D2D communication on a device-to-device direct interface (e.g., a PC5 interface or a side link) 103. The D2D communication includes at least direct communication (ProSe direct communication) and may also include direct discovery (e.g., ProSe direct discovery). The eNB 2 manages a cell 21 and is capable of performing cellular communication (101 or 102) with each of a plurality of UEs 1 by using a cellular communication technology (e.g., an evolved universal terrestrial radio access (E-UTRA) technology). Although for the sake of simplicity of description, Figure 4 The example of indicates an arrangement in which UE 1A and 1B are located in the same cell 21, but this arrangement is only an example. For example, UE 1A may be located in one of two cells that are adjacent to each other and managed by different eNBs 2, and UE 1B may be located in the other of the two cells. Alternatively, at least one of UE 1A and UE 1B may be located outside the coverage of one or more eNBs 2.

[0066] The following provides a description of PSCCH and PSSCH transmission on the side link according to this embodiment. A transmitting terminal (e.g., UE 1A) is configured to perform data transmission to other wireless terminals (i.e., receiving terminals (e.g., UE 1B)) according to a periodically occurring D2D control period (i.e., a side link control period (PSCCH period)) without passing through eNB 2. As previously described, each side link control period includes a subframe pool for PSCCH (a first subframe pool) and a subframe pool for PSSCH (a second subframe pool). The subframe pool for PSCCH consists of L subframes that can be used to send side link control information (SCI) containing scheduling assignment information (i.e., SCI format 0). PSCCHOn the other hand, the subframe pool for PSSCH consists of L subframes that can be used for data transmission (ie, PSSCH transmission) according to the scheduling assignment information (ie, SCI format 0). PSSCH subframes.

[0067] Specifically, the transmitting terminal (e.g., UE 1A) transmits sidelink control information (D2D control information) in one or more subframes (e.g., two subframes) in the PSCCH subframe pool within the j-th sidelink control period. In addition, the transmitting terminal (e.g., UE 1A) performs data transmission (PSSCH transmission) according to the sidelink control information in one or more subframes in the PSSCH subframe pool within the j-th sidelink control period. The sidelink control information transmitted within the j-th sidelink control period includes a first information element (i.e., scheduling assignment information (SCI format 0)), which is used to identify one or more subframes in the PSSCH subframe pool within the j-th sidelink control period. In addition, the sidelink control information transmitted in the j-th sidelink control period includes a second information element, which indicates whether the radio resource allocation for data transmission (PSSCH transmission) indicated by the sidelink control information will be valid in at least one of the (j+1)-th sidelink control period and the subsequent sidelink control period.

[0068] The transmitting terminal (e.g., UE 1A) may be configured to perform data transmission on the PSSCH without transmitting new sidelink control information (i.e., scheduling assignment information (SCI format 0)) in at least one of the (j+1)th sidelink control period and the subsequent sidelink control period in which the radio resource allocation for data transmission in the jth sidelink control period continues to be valid. At the same time, the receiving terminal (e.g., UE 1B) may be configured to perform data reception on the PSSCH without receiving new sidelink control information (i.e., scheduling assignment information) in the (j+1)th sidelink control period and the subsequent sidelink control period when the radio resource allocation for data transmission in the jth sidelink control period continues to be valid in at least one of the (j+1)th sidelink control period and the subsequent sidelink control period.

[0069] Therefore, the probability that the transmitting terminal cannot receive the side link control information from another UE 1 in at least one of the (j+1)th side link control period and the subsequent side link control period can be reduced. In addition, according to the result of the PSCCH transmission of the present embodiment, the number of PSCCH transmissions can be reduced compared with the case where the side link control information (i.e., scheduling assignment information) is transmitted in each side link control period. Therefore, the probability of the following conflict occurring: PSCCH transmissions by multiple side link transmitting terminals located close to each other are performed in the same radio resource can be reduced.

[0070] In some implementations, the second information element may specify the length of at least one of the (j+1)th sidelink control period and the subsequent sidelink control period (i.e., at least one sidelink control period during which the radio resource allocation for data transmission in the jth sidelink control period is valid). For example, the second information element may specify the number of sidelink control periods during which the sidelink control information (i.e., scheduling assignment information (SCI format 0)) transmitted in the jth sidelink control period is valid.

[0071] The transmitting terminal may autonomously determine the number of side link control periods during which the radio resource allocation for data transmission in the jth side link control period is continuously valid (hereinafter referred to as the "number of valid side link control periods"). Alternatively, the eNB 2 may set the number of valid side link control periods for radio resource allocation for the transmitting terminal. For example, in the case of scheduled resource allocation (i.e., side link transmission mode 1), the eNB 2 may notify the transmitting terminal of the number of valid side link control periods for radio resource allocation by using a side link scheduling grant (DCI format 5). In the case of autonomous resource selection (i.e., side link transmission mode 2), the eNB 2 may notify the transmitting terminal of the number of valid side link control periods for radio resource allocation by using PSCCH resource configuration or PSSCH resource configuration via SIB 18 or RRC signaling.

[0072] For example, the transmitting terminal may determine the number of valid side link control periods for radio resource allocation according to the amount of data in the data buffer to be transmitted on the side link. Specifically, the transmitting terminal may determine the number of valid side link control periods corresponding to the PSSCH resources required to send the pending data. As a result, the number of transmissions of the side link control information (scheduling assignment information (SCI format 0)) on the PSCCH can be appropriately reduced.

[0073] For example, the transmitting terminal may determine the number of valid side link control periods for radio resource allocation according to the delay requirement required by the application (i.e., application program). The delay requirement may be at least one of: maximum delay; average delay, and priority associated with delay guarantee. When the application requires strict delay requirements, the transmitting terminal increases the number of valid side link control periods compared to when the application does not require strict delay requirements (i.e., low delay). This can suppress the reception failure of side link control information and the transmission failure of data for a long period of time, thereby helping to achieve the strict delay requirements (i.e., low delay) required by the application.

[0074] For example, the eNB 2 may set the number of valid sidelink control periods for the transmitting terminal according to the number of sidelink transmissions (or the number of sidelink transmitting terminals) in the cell 21. For example, the eNB 2 may increase the number of valid sidelink control periods as the number of sidelink transmissions (or the number of sidelink transmitting terminals) in the cell 21 increases. This can reduce the number of occurrences of PSCCH transmissions when the number of sidelink transmissions (or the number of sidelink transmitting terminals) performed in the cell 21 is large. Therefore, it is possible to reduce the probability of the occurrence of the following collisions: multiple PSCCH transmissions performed by multiple sidelink transmitting terminals located close to each other are performed in the same radio resource.

[0075] Alternatively, in some implementations, the second information element may indicate whether the radio resource allocation for data transmission in the j-th side link control period is maintained. The second information element may be flag information indicating whether the radio resource allocation is maintained. For example, the second information element may be 1-bit flag information. A flag with a value of "1" may indicate that the radio resource allocation for data transmission in the j-th side link control period is also valid in the (j+1)-th side link control period and subsequent side link control periods. On the other hand, a flag with a value of "0" may indicate that the radio resource allocation for data transmission in the j-th side link control period is only valid in the j-th side link control period.

[0076] Figure 5 is a view showing an example of transmission of PSCCH and PSSCH according to this embodiment. Figure 5 In the example of , the transmitting terminal (e.g., UE 1A) transmits sidelink control information (522 and 523) on the PSCCH in two subframes within a PSCCH subframe pool 511 within a j-th sidelink control period (PSCCH period) 501. The sidelink control information 522 and 523 transmitted in the j-th sidelink control period 501 include scheduling assignment information (i.e., SCI format 0), and also indicate that the scheduling assignment information is also valid in the (j+1)-th sidelink control period and subsequent sidelink control periods.

[0077] The transmitting terminal (e.g., UE 1A) performs data transmission (PSSCH transmission) 531 to 534 in a plurality of subframes in the PSSCH subframe pool 512 in the j-th sidelink control period 501 according to the sidelink control information 522 and 523. In addition, the transmitting terminal (e.g., UE 1A) performs data transmission (PSSCH transmission) 535 to 538 in the PSSCH subframe pool 514 in the (j+1)-th sidelink control period 502 without transmitting the sidelink control information in the PSCCH subframe pool 513 in the (j+1)-th sidelink control period 502. The data transmission (PSSCH transmission) 535 to 538 is performed according to the sidelink control information 522 and 523 previously transmitted in the j-th sidelink control period 501. Likewise, the transmitting terminal (e.g., UE 1A) performs data transmission (PSSCH transmission) 539 to 542 in the PSSCH subframe pool 516 in the (j+2)th sidelink control period 503, without transmitting the sidelink control information in the PSCCH subframe pool 515 in the (j+2)th sidelink control period 503. Data transmission (PSSCH transmission) 539 to 542 is performed according to the sidelink control information 522 and 523 previously transmitted in the jth sidelink control period 501.

[0078] Figure 6 6 is a flowchart showing an example of the operation (process 600) of the transmitting terminal (e.g., UE 1A) according to the embodiment. In block 601, in the j-th sidelink control period (PSCCH period), the transmitting terminal sends to the receiving terminal (e.g., UE 1B) sidelink control information (SCI) indicating the PSSCH resource and also indicating the validity of the PSSCH resource allocation in the (j+1)-th sidelink control period and the subsequent sidelink control period (i.e., PSCCH period). In block 602, in the j-th sidelink control period (PSCCH period), the transmitting terminal sends data on the PSSCH according to the sidelink control information of the j-th sidelink control period.

[0079] In box 603, the transmitting terminal determines whether there is pending data to be sent on the side link in the buffer. When there is pending data in the buffer ("Yes" in box 603), the transmitting terminal determines whether it has a valid scheduling assignment for the receiving terminal of the pending data (box 604). When it has a valid scheduling assignment ("Yes" in box 604), the transmitting terminal sends data on the PSSCH in the (j+1)th side link control period or a subsequent side link control period (i.e., PSCCH period) according to the side link control information of the jth side link control period. On the other hand, when it does not have a valid scheduling assignment ("No" in box 604), the transmitting terminal returns to the processing in box 601 to send new side link control information (i.e., retrieve the assignment information (SCI format 0)).

[0080] Figure 7 7 is a flowchart showing an example of the operation (process 700) of the receiving terminal (e.g., UE 1B) according to the embodiment. In block 701, in the j-th sidelink control period (PSCCH period), the receiving terminal receives sidelink control information (SCI) indicating the PSSCH resource and also indicating the validity of the PSSCH resource allocation in the (j+1)-th sidelink control period and the subsequent sidelink control period (i.e., PSCCH period) from the transmitting terminal (e.g., UE 1A). In block 702, in the j-th sidelink control period (PSCCH period), the receiving terminal receives data on the PSSCH according to the sidelink control information of the j-th sidelink control period.

[0081] In block 703, the receiving terminal determines whether it has a valid scheduling assignment. When it has a valid scheduling assignment ("Yes" in block 604), the receiving terminal receives data on the PSSCH in the (j+1)th sidelink control period or a subsequent sidelink control period (i.e., a PSCCH period) according to the sidelink control information of the jth sidelink control period.

[0082] Figure 8 700 is a flowchart showing one example of the operation (process 700) of the eNB 2 according to this embodiment. As described previously, the eNB 2 can set the number of valid side link control periods for radio resource allocation for the transmitting terminal. Figure 8801, eNB 2 determines the number of valid sidelink control periods for radio resource allocation for sidelink transmission. In block 802, eNB 2 sends a sidelink scheduling grant indicating that sidelink transmission is allowed in a plurality of sidelink control periods (i.e., PSCCH periods) to UE1 (transmitting terminal). Specifically, the sidelink scheduling grant indicates PSCCH transmission resource allocation, PSSCH transmission resource allocation, and the number of sidelink control periods during which the PSSCH transmission resource allocation is valid.

[0083] Second embodiment

[0084] This embodiment provides a modified example of the side link transmission described in the first embodiment. Figure 4 The configuration is the same as shown in . In this embodiment, a process of deactivating (or canceling) PSSCH resource allocation within multiple sidelink control periods is described.

[0085] In some embodiments, a transmitting terminal (e.g., UE 1A) may be configured to transmit sidelink control information to a receiving terminal (e.g., UE 1B) in any one of the (j+1)th sidelink control period and subsequent sidelink control periods, the sidelink control information indicating deactivation of radio resource allocation for the (j+1)th data transmission or subsequent data transmission (i.e., PSSCH transmission) based on the sidelink control information (scheduling assignment information) previously transmitted in the jth sidelink control period. In other words, the transmitting terminal may transmit sidelink control information in any one of the (j+1)th sidelink control period and subsequent sidelink control periods, the sidelink control information indicating deactivation (or cancellation) of the scheduling assignment to deactivate the PSSCH scheduling assignment (SCI format 0) in the jth sidelink control period valid within a plurality of sidelink control periods.

[0086] A reserved value for the number of valid periods of a scheduling assignment (e.g., a value such as 11111111 in the case of 8 bits) may be used as sidelink control information indicating deactivation (or cancellation) of a scheduling assignment. Alternatively, the sidelink control information indicating deactivation (or cancellation) of a scheduling assignment may include a flag indicating deactivation of the scheduling assignment.

[0087] It is noted that multiple scheduling assignments between the transmitting terminal and the receiving terminal may be enabled. In this case, the receiving terminal may disable all valid scheduling assignments in response to information indicating deactivation (or cancellation) received from the transmitting terminal. Alternatively, the transmitting terminal may send an identifier indicating a scheduling assignment to be disabled among multiple valid scheduling assignments to the receiving terminal.

[0088] Alternatively or additionally, in some implementations, the receiving terminal (e.g., UE 1B) may autonomously deactivate (or cancel) a scheduling assignment valid in a plurality of sidelink control periods. For example, when no data is received from the transmitting terminal (e.g., UE 1A) on the PSSCH during a specified period in the (j+1)th sidelink control period and subsequent sidelink control periods, the receiving terminal (e.g., UE 1B) may deactivate the scheduling assignment (i.e., PSSCH resource allocation) enabled in the jth sidelink control period.

[0089] When scheduling assignments (i.e., PSSCH resource allocations) are enabled in multiple side link control periods, there is the possibility that, because there is no pending data to be sent in the buffer of the transmitting terminal (i.e., the side link transmission has been completed), the receiving terminal attempts to receive data on the PSSCH in each side link control period within the valid side link control period, even though no data transmission on the PSSCH occurs in the (j+1)th side link control period and subsequent side link control periods. This unnecessary reception operation causes unnecessary power consumption or reduced transmission opportunities in the receiving terminal. According to the scheduling assignment deactivation process described in this embodiment, this adverse consequence can be suppressed.

[0090] Fig. 9 900 is a flowchart showing an example of the operation of the transmitting terminal according to the embodiment. In block 901, the transmitting terminal determines that data transmission has been completed when the PSSCH resource allocation for multiple sidelink control periods (i.e., PSCCH periods) is valid. In block 902, the transmitting terminal sends sidelink control information to the receiving terminal, which indicates to deactivate the PSSCH resource allocation for multiple sidelink control periods (i.e., PSCCH periods).

[0091] Fig.10 1 is a flowchart showing an example of the operation (process 1000) of the receiving terminal according to the embodiment. In block 1001, the receiving terminal detects that no data is received from the transmitting terminal on the PSSCH within a specified period when the PSSCH resource allocation for multiple side link control periods (i.e., PSCCH periods) is valid. In block 1002, the receiving terminal autonomously deactivates the PSSCH resource allocation for multiple side link control periods (i.e., PSCCH periods).

[0092] Third embodiment

[0093] This embodiment provides a modified example of the side link transmission described in the first embodiment. Figure 4In this embodiment, the transmitting terminal (e.g., UE 1A) is configured to impose restrictions on PSSCH resource allocation within multiple sidelink control periods on the transmitting terminal itself, either autonomously or under the control of eNB 2. In this embodiment, an example of independently imposing restrictions on a specific UE 1 or a specific UE group in cell 21 is described.

[0094] In some implementations, when it is assumed that the transmitting terminal is located at a cell boundary between the cell 21 (i.e., the serving cell) of the eNB 2 and a neighboring cell, the transmitting terminal may autonomously or under the control of the eNB 2 impose a restriction on the transmitting terminal itself regarding the PSSCH resource allocation within a plurality of sidelink control periods. In this case, the restriction may indicate that the PSSCH resource allocation is not allowed to be enabled continuously within a plurality of sidelink control periods. Alternatively, the restriction may set an upper limit value to the number of sidelink control periods during which the PSSCH resource allocation is valid (i.e., the number of valid control periods).

[0095] The fact that the transmitting terminal is located at the cell boundary may be determined by any one or any combination of the following conditions (a) to (d):

[0096] (a) the reception quality of the downlink signal of the serving cell 21 (for example, reference signal received power (RSRP) or reference signal received quality (RSRQ)) is equal to or less than a specified value;

[0097] (b) the reception quality of the downlink signal on the neighboring cell is equal to or higher than a specified value;

[0098] (c) the distance from the eNB 2 serving cell 21 is equal to or greater than a specified value; and

[0099] (d) The distance to the eNB of the neighboring cell is equal to or less than a specified value.

[0100] Assuming that the transmitting terminal is located at the cell boundary between the cell 21 (i.e., the serving cell) of the eNB 2 and the neighboring cell, the transmitting terminal may cause interference to the UE or the eNB of the neighboring cell. Therefore, in other words, when the transmitting terminal may cause interference to the UE or the eNB of the neighboring cell, the transmitting terminal may impose restrictions on the PSSCH resource allocation within a plurality of side link control periods on the transmitting terminal itself, either autonomously or under the control of the eNB 2.

[0101] Fig.111 is a flow chart showing an example of the operation (process 1100) of a transmitting terminal according to this embodiment. In block 1101, the transmitting terminal detects that it is located at a cell boundary. In block 1102, the transmitting terminal imposes restrictions on PSSCH resource allocation for multiple sidelink control periods (i.e., PSCCH periods).

[0102] The sidelink transmission performed by the transmitting terminal located at the cell boundary may interfere with the sidelink transmission or uplink transmission performed in the adjacent cell. In this embodiment, restrictions on PSSCH resource allocation within multiple sidelink control periods may be set for the transmitting terminal, thereby avoiding the situation where the transmitting terminal continuously interferes with the sidelink transmission or uplink transmission performed in the adjacent cell.

[0103] Fourth embodiment

[0104] This embodiment provides a modified example of the side link transmission described in the first embodiment. Figure 4 In this embodiment, the transmitting terminal (e.g., UE 1A) is configured to impose restrictions on PSSCH resource allocation within multiple sidelink control periods on the transmitting terminal itself under the control of eNB 2. In this embodiment, an example of independently imposing restrictions on a specific UE 1 or a specific UE group in cell 21 is described.

[0105] In some implementations, when the number of sidelink transmissions (or the number of sidelink transmission terminals) in cell 21 exceeds a specified value, eNB 2 may impose restrictions on PSSCH resource allocation within multiple sidelink control periods on some or all of the sidelink transmission terminals in cell 21. In this case, the restriction may set a lower limit value (not less than 2) to the number of sidelink control periods during which the PSSCH resource allocation is valid (i.e., the number of valid control periods). As a result, when the number of sidelink transmissions (or the number of sidelink transmission terminals) performed by eNB 2 in cell 21 is large, the number of occurrences of PSCCH transmissions is reduced. Therefore, the utilization rate of the PSCCH resource pool can be reduced. Therefore, the probability of the following conflict occurring can be reduced: PSCCH transmissions performed by multiple sidelink transmission terminals located close to each other are performed in the same radio resource.

[0106] Fig.121 is a flowchart showing an example of the operation (process 1200) of the eNB 2 according to this embodiment. In block 1201, the eNB 2 detects that the number of sidelink transmissions (i.e., D2D transmissions) performed in the cell 21 exceeds a specified value. In block 1202, the eNB 2 imposes restrictions on PSSCH resource allocation within multiple sidelink control periods (i.e., PSSCH periods) on one or more sidelink (D2D) transmitting terminals in the cell 21.

[0107] Finally, a configuration example of the UE 1 according to the above-described embodiment will be described. Fig.13 yes Figure 1 The above-mentioned UE 1 as a transmitting terminal and UE 1 as a receiving terminal may have Fig.13 The configuration shown in . The radio frequency (RF) transceiver 1301 performs analog RF signal processing for communicating with the eNB 2. The analog RF signal processing performed by the RF transceiver 1301 includes up-conversion, down-conversion and amplification. The RF transceiver 1301 is connected to the antenna 1302 and the baseband processor 1303. Specifically, the RF transceiver 1301 receives modulated symbol data (or OFDM symbol data) from the baseband processor 1303, generates a transmit RF signal and supplies the transmit RF signal to the antenna 1302. In addition, the RF transceiver 1301 generates a baseband receive signal based on the receive RF signal received by the antenna 1302, and supplies it to the baseband processor 1303.

[0108] The baseband processor 1303 performs digital baseband signal processing (i.e., data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) synthesis / decomposition of transmission formats (i.e., transmission frames), (d) channel coding / decoding, (e) modulation (i.e., symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) by inverse fast Fourier transform (IFFT). On the other hand, control plane processing includes communication management of layer 1 (e.g., transmit power control), layer 2 (e.g., radio resource management and hybrid automatic repeat request (HARQ) processing), and layer 3 (e.g., regarding attachment, mobility, and call management).

[0109] For example, in the case of LTE and LTE-Advanced, the digital baseband signal processing performed by the baseband processor 1303 may include signal processing of a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a MAC layer, and a PHY layer. In addition, the control plane processing performed by the baseband processor 1303 may include processing of a non-access stratum (NAS) protocol, an RRC protocol, and a MAC CE.

[0110] The baseband processor 1303 may include a modem processor (e.g., a digital signal processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., a central processing unit (CPU) or a microprocessing unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be made common to the application processor 1304 described below.

[0111] The application processor 1304 is also called a CPU, an MPU, a microprocessor, or a processor core. The application processor 1304 may include multiple processors (multiple processor cores). The application processor 1304 loads a system software program (operating system (OS)) and various application programs (e.g., a voice call application, a web browser, an email program, a camera operation application, and a music player application) from the memory 1306 or from other memories (not shown) and executes these programs, thereby providing various functions of the UE1.

[0112] In some implementations, such as Fig.13 As indicated by the dotted line (1305) in FIG. 1 , the baseband processor 1303 and the application processor 1304 may be integrated on a single chip. In other words, the baseband processor 1303 and the application processor 1304 may be implemented in a single system on chip (SoC) device 1305. The SoC device may be referred to as a system large-scale integrated circuit (LSI) or a chipset.

[0113] The memory 1306 is a volatile memory, a non-volatile memory, or a combination thereof. The memory 1306 may include a plurality of storage devices that are physically independent of each other. The volatile memory is, for example, a static random access memory (SRAM), a dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is, for example, a mask read-only memory (MROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a hard disk drive, or any combination thereof. The memory 1306 may include, for example, an external storage device accessible to the baseband processor 1303, the application processor 1304, and the SoC 1305. The memory 1306 may include an internal storage device integrated in the baseband processor 1303, the application processor 1304, and the SoC 1305. In addition, the memory 1306 may include a memory in a universal integrated circuit card (UICC).

[0114] The memory 1306 may store software modules (computer programs) including instructions and data used by the UE described in the above multiple embodiments to perform processing. In some implementations, the baseband processor 1303 or the application processor 1304 may be configured to load the software module from the memory 1306 and execute the loaded software module, thereby performing the processing of the UE1 described in the above embodiments.

[0115] Fig.14 2 is a block diagram showing a configuration example of a base station (eNB) 2 according to the above-described embodiment. Fig.14 , the base station 2 includes an RF transceiver 1401, a network interface 1403, a processor 1404 and a memory 1405. The RF transceiver 1401 performs analog RF signal processing for communicating with the wireless terminal 1. The RF transceiver 1401 may include a plurality of transceivers. The RF transceiver 1401 is connected to an antenna 1402 and a processor 1404. The RF transceiver 1401 receives modulated symbol data (or OFDM symbol data) from the processor 1404, generates a transmit RF signal and supplies the transmit RF signal to the antenna 1402. In addition, the RF transceiver 1401 generates a baseband receive signal based on the receive RF signal received by the antenna 1402, and supplies it to the processor 1404.

[0116] The network interface 1403 is used to communicate with network nodes, such as a mobility management entity (MME) and a serving gateway (S-GW). The network interface 1403 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0117] The processor 1404 performs digital baseband signal processing (i.e., data plane processing) and control plane processing for wireless communication. For example, in the case of LTE and LTE-Advanced, the digital baseband signal processing performed by the processor 1404 may include signal processing of the PDCP layer, the RLC layer, the MAC layer, and the PHY layer. In addition, the control plane processing performed by the processor 1404 may include processing of the S1 protocol, the RRC protocol, and the MAC CE.

[0118] The processor 1404 may include a plurality of processors. For example, the processor 1404 may include a modem processor (eg, DSP) that performs digital baseband signal processing and a protocol stack processor (eg, CPU or MPU) that performs control plane processing.

[0119] The memory 1405 is a combination of volatile and non-volatile memory. The volatile memory is, for example, SRAM, DRAM, or a combination thereof. The non-volatile memory is, for example, MROM, PROM, flash memory, hard disk drive, or any combination thereof. The memory 1405 may include a memory arranged separately from the processor 1404. In this case, the processor 1404 may access the memory 1405 through the network interface 1403 or an I / O interface (not shown).

[0120] The memory 1405 may store software modules (computer programs) including instructions and data used by the base station 2 described in the above multiple embodiments to perform processing. In some implementations, the processor 1404 may be configured to load the software module from the memory 1405 and execute the loaded software module, thereby performing the processing of the base station 2 described in the above embodiments.

[0121] As reference Fig.13 and Fig.14 As described, each processor included in the UE 1 and the eNB 2 according to the above embodiment executes one or more programs, which include a set of instructions that cause the computer to execute the algorithm described above with reference to the accompanying drawings. These programs can be stored in various types of non-transitory computer-readable media, thereby being supplied to the computer. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (such as floppy disks, magnetic tapes, and hard disk drives), magneto-optical recording media (such as magneto-optical disks), compact disk read-only memories (CD-ROMs), CD-Rs, CD-R / Ws, and semiconductor memories (such as mask ROMs, programmable ROMs (PROMs), erasable PROMs (EPROMs), flash ROMs, and random access memories (RAMs)). These programs can be supplied to the computer by using various types of transient computer-readable media. Examples of transient computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transient computer-readable media can be used to supply programs to computers via wired communication lines (e.g., wires and optical fibers) or wireless communication lines.

[0122] Other embodiments

[0123] Each of the above embodiments may be used independently, or two or more of the embodiments may be combined with each other as appropriate.

[0124] The above embodiments are not limited to LTE-Advanced and its improved forms, and can be applied to D2D communications in other mobile communication networks or systems.

[0125] In addition, the above-described embodiments are merely examples of application of the technical ideas obtained by the inventors. These technical ideas are not limited to the above-described embodiments, and various modifications may be made thereto.

[0126] This application is based upon and claims the benefit of priority from Japanese patent application No. 2015-141124, filed on Jul. 15, 2015, the disclosure of which is incorporated herein in its entirety by reference.

[0127] Reference Symbols List

[0128] 1UE

[0129] 2eNB

[0130] 1301 Radio Frequency (RF) Transceiver

[0131] 1303 Baseband Processor

[0132] 1304 Application Processor

[0133] 1306CPU

[0134] 1401 RF Transceiver

[0135] 1404 Processor

[0136] 1405 Memory

Claims

1. A method of a wireless terminal, the method comprising: Sending a physical sidelink control channel PSCCH, wherein the PSCCH includes sidelink control information used for scheduling a physical sidelink shared channel PSSCH in a j-th sidelink control period; as well as The PSSCH is transmitted in a first radio resource allocation in the j-th sidelink control period, wherein The sidelink control information includes a first information element and a second information element, the first information element indicating the first radio resource allocation for transmission of the PSSCH, The second information element indicates whether the first radio resource allocation is allowed in each of the j+1th sidelink control period and the subsequent sidelink control period, wherein The method comprises, based on the first information element and the second information element, transmitting the PSSCH in the first radio resource allocation in each of a j+1 th sidelink control period and a subsequent sidelink control period, Wherein, the side link control period occurs periodically.

2. A wireless terminal, comprising: one or more memories for storing instructions; as well as One or more processors configured to process the instructions to control the wireless terminal: transmitting a physical sidelink control channel PSCCH including sidelink control information used for scheduling a physical sidelink shared channel PSSCH in a j-th sidelink control period, and The PSSCH is transmitted in a first radio resource allocation in the j-th sidelink control period, wherein The sidelink control information includes a first information element and a second information element, the first information element indicating the first radio resource allocation for transmission of the PSSCH, The second information element indicates whether the first radio resource allocation is allowed in each of the j+1th sidelink control period and the subsequent sidelink control period, wherein The one or more processors are configured to process the instructions to control the wireless terminal to: transmit the PSSCH in the first radio resource allocation in each of a j+1th sidelink control period and a subsequent sidelink control period based on the first information element and the second information element, Wherein, the side link control period occurs periodically.

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