WO2017017871A1 - Terminal, base station and methods therefor - Google Patents

Abstract

A reception terminal (1B) receives D2D control information (522, 523) transmitted from a transmission terminal (1A) over a physical control channel (511) during a D2D control period (501). The D2D control information (522, 523) indicates that one or more radio resources during the D2D control period (501) are designated as scheduled radio resources (533-534) via which a physical data channel is possibly to be transmitted. If the transmission of the physical data channel from the transmission terminal (1A) via these scheduled radio resources (533-534) is not detected in the physical layer of the reception terminal (1B), the MAC layer of the reception terminal (1B) transmits no negative feedback to the transmission terminal (1A). This can contribute, for example, to suppression of transmission of unnecessary negative feedbacks from the reception terminal to the transmission terminal in D2D transmissions.

Description

Terminal, base station and methods thereof

This disclosure relates to direct communication between devices (device-to-device (D2D) communication), and particularly relates to allocation of radio resources for D2D communication.

A form in which a wireless terminal communicates directly with another wireless terminal without going through an infrastructure network such as a base station is called device-to-device (D2D) communication. The D2D communication includes at least one of direct communication (Direct Communication) and direct discovery (Direct Discovery). In some implementations, a plurality of wireless terminals that support D2D communication form a D2D communication group autonomously or according to a network instruction, and communicate with other wireless terminals in the D2D communication group.

Proximity-based services (ProSe) defined in 3GPP Release 12 is an example of D2D communication (see, for example, Non-Patent Document 1). ProSe Direct Discovery is a wireless terminal that can execute ProSe (ProSe-enabled User Equipment (UE)) and other ProSe-enabled UEs. -UTRA) It is performed by the discovery procedure using only the technology (technology). ProSe direct discovery may be performed by three or more ProSe-enabled UEs.

ProSe direct communication enables the establishment of a communication path between two or more ProSe-enabled UEs existing in the direct communication range after the ProSe direct discovery procedure. In other words, ProSe direct communication allows ProSe-enabled UEs to communicate with other ProSe-enabled UEs without going through a public land mobile communication network (Public Land Mobile Mobile Network (PLMN)) that includes a base station (eNodeB (eNB)). Allows to communicate directly with. ProSe direct communication may be performed using the same wireless communication technology (E-UTRA technology) as that used to access the base station (eNB), or wireless technology of Wireless Local Area Network (WLAN) (ie IEEE 802.11 (radio technology) may be used.

In 3GPP Release 12, a wireless link between wireless terminals used for direct communication or direct discovery is referred to as a side link (see, for example, Section 14 of Non-Patent Document 2). Sidelink transmission uses the same frame structure as the Long Term Evolution (LTE) frame structure defined for uplink and downlink, and uses a subset of uplink resources in frequency and time domain. The radio terminal (UE) performs side link transmission using single carrier frequency division multiplexing (Single-Carrier-FDMA (Frequency-Division-Multiple Access), SC-FDMA) similar to the uplink.

In 3GPP Release 12 ProSe, radio resources for side link transmission are allocated to UEs by a radio access network (e.g., Evolved Universal Terrestrial Radio Access Network (E-UTRAN)). The UE that has been permitted side link communication by ProSe function performs ProSe direct discovery or ProSe direct communication using radio resources allocated by the radio access network node (e.g., eNB (eNB)).

For ProSe direct communication, two resource allocation modes, namely scheduled resource resource allocation and scheduled resource resource allocation and automatic resource resource selection are called "sidelink transmission mode 1" and "sidelink transmission mode 2", respectively. (See Section 14 of Non-Patent Document 2).

In scheduled resource allocation of ProSe direct communication, when a UE desires side link transmission, the UE requests radio resource allocation for side link transmission from the eNB, and the eNB assigns resources for side link control and data. Assign to the UE. Specifically, the UE sends a scheduling request to the eNB to request an uplink (UL) data transmission resource (Uplink Shared Channel (UL-SCH) resource) and assigns it with an UL grant. Send Sidelink Buffer Status Report (Sidelink BSR) to the eNB in the received UL data transmission resource. The eNB determines a side link transmission resource to be allocated to the UE based on the Sidelink BSR, and transmits a side link grant (SL grant) to the UE.

SL grant is defined as Downlink Control Information (DCI) format 5. SL grant (DCI format 含 む 5) includes contents such as Resource for PSCCH, Resource block assignment and hopping allocation, and time resource pattern index. Resource for PSCCH indicates a radio resource for a side link control channel (i.e., Physical Sidelink Control Channel (PSCCH)). Resource block assignment and hopping allocation is a set of frequency resources, ie subcarriers (resource blocks), for transmitting sidelink data channels (ie, Physical Sidelink Shared Channel (PSSCH)) for data transmission on the sidelink Used to determine. Time resource pattern index is used to determine a time resource for transmitting PSSCH, that is, a set of subframes. Strictly speaking, a resource block means LTE and LTE-Advanced time-frequency resources, and a plurality of OFDM (or SC-FDMA) symbols continuous in the time domain and a plurality of consecutive OFDM symbols in the frequency domain. A resource unit defined by subcarriers. In the case of Normal cyclic prefix, one resource block includes 12 OFDM (or SC-FDMA) symbols continuous in the time domain and 12 subcarriers in the frequency domain. That is, Resource block assignment and hopping allocation and Time resource pattern index specify a resource block for transmitting PSSCH. The UE (that is, the side link transmission terminal) determines the PSCCH resource and the PSSCH resource according to SL grant.

On the other hand, in autonomous resource selection of ProSe direct communication, the UE autonomously selects a resource for side link control (PSCCH) and data (PSSCH) from the resource pool set by the eNB. The eNB may assign a resource pool to be used for autonomous resource selection in the System Information Block (SIB) 18 to the UE. Note that the eNB may assign a resource pool to be used for autonomous resource selection to the UE of Radio Resource Control (RRC) _CONNECTED by dedicated RRC signaling. This resource pool may also be available when the UE is RRC_IDLE.

When performing direct transmission on the side link, the transmitting UE (D2D transmitting UE) (hereinafter referred to as the transmitting terminal) uses the radio resource area (resource pool) for the side link control channel (ie, PSCCH). Then, scheduling assignment information (Scheduling Assignment) is transmitted. The scheduling allocation information is also called Sidelink, 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 scheduled resource allocation described above, the resource block, assignment, and hopping resource allocation and time resource resource pattern index indicated by the scheduling resource assignment (SCI format 0) and the resource resource block assignment, and hopping resource allocation indicated by the SL resource grant (DCI resource format 5) received from the eNB Follow time resource pattern index.

The transmitting terminal transmits data on PSSCH using radio resources according to the scheduling allocation information. A receiving UE (D2D receiving UE) (hereinafter referred to as a receiving terminal) receives scheduling assignment information from the transmitting terminal on the PSCCH, and receives data on the PSSCH according to the scheduling assignment information. Here, the term “transmission terminal” is an expression that focuses on the transmission operation of the wireless terminal, and does not mean a wireless terminal dedicated to transmission. Similarly, the term “receiving terminal” is an expression that focuses on the receiving operation of the wireless terminal, and does not mean a terminal dedicated to reception. That is, the transmitting terminal can also perform a receiving operation, and the receiving terminal can also perform a transmitting operation.

In the following, a sidelink control period (sidelink control period), a resource pool for PSCCH, and a resource pool for PSSCH will be described. These are necessary for determining radio resources (i.e., subframes and resources blocks) for transmitting PSCCH and radio resources for transmitting PSSCH. As already described, the PSCCH is a side link physical channel used for transmission of side link control information (Sidelink Control Information (SCI)) such as scheduling allocation information. On the other hand, PSSCH is a side link physical channel used for user data transmission (direct transmission).

The side link control period is a scheduling period for the side link (see FIG. 1). The side link control period is also referred to as PSCCH period. The transmitting terminal transmits scheduling allocation information (i.e., “SCI format” 0) for each side link control period. In 3GPP Release 12, the side link control period is 40ms, 60ms, 70ms, 80ms, 120ms, 140ms, 160ms, 240ms, 280ms, or 320ms. In other words, the side link control period is 40 subframes, 60 subframes, 70 subframes, 80 subframes, 120 subframes, 140 subframes, 160 subframes, 240 subframes, 280 subframes, or 320 subframes. is there.

Therefore, the transmitting terminal notifies the receiving terminal of the allocation of PSSCH resources every side link control period, that is, at a cycle of 40 μms or more. However, PSSCH resource allocation is specified in units of 6, 7 or 8 subframes (6, 7 or 8 or 8 ms) using time-resource-pattern-index. Therefore, during one side link control period, the same PSSCH resource allocation is used in 6, 7 or 8 subframe periods.

In one side link control period, the transmitting terminal transmits scheduling allocation information (ie, SCI format 0) in two subframes among L _PSCCH subframes included in a resource pool (subframe pool) for _PSCCH. Send twice. These two transmissions are performed in two different resource blocks among the M ^PSCCH_RP _RB resource blocks included in the resource pool (resource block pool) for ^PSCCH .

The resource pool for PSCCH is set by the eNB to the UE by broadcast (SIB 18) or dedicated signaling (RRC signaling). The resource pool for _PSCCH consists of L _PSCCH subframes and M ^PSCCH_RP _RB frequency domain resource blocks in the side link control period.

The resource pool designation method for PSCCH will be described with reference to FIGS. The resource pool for PSCCH consists of a subframe pool and a resource block pool. FIG. 2 shows a subframe pool for PSCCH, and FIG. 3 shows a resource block pool for PSCCH.

The eNB specifies the length of the side link control period (PSCCH period) (P), as well as the subframe bitmap for PSCCH and its length (N ') to identify the subframe pool for PSCCH. Is specified. The length (N ′) of the subframe bitmap is 4, 8, 12, 16, 30, 40 or 42 bits. As shown in FIG. 2, the N ′ subframe corresponding to the subframe bitmap is the first N ′ subframe in the side link control period. The subframe bitmap indicates that the subframe corresponding to the bit set to “0” is not used for PSCCH transmission, and the subframe corresponding to the bit set to “1” can be used for PSCCH transmission. Show. Therefore, the number of subframes (L _PSCCH ) included in the PSCCH resource pool within one side link control period is equal to the number specified as 1 in the subframe bitmap. The subframes included in the PSCCH resource pool (ie, subframe pool) can be expressed as follows:

On the other hand, as shown in FIG. 3, in order to identify the resource block pool for PSCCH, the eNB starts (starts) PhysicalPhysResource Block (PRB) index (S1), and ends (end) PRB index ( Specify S2) and the number of PRBs (M). The resource block pool has PRB index q greater than or equal to the start index (S1) and smaller than S1 + M (S1 <= q <S1 + M) M PRBs, and PRB index q is greater than S2-M In addition, it includes M PRBs that are equal to or less than the end index (S2) (S2-M <q <= S2) (that is, 2M PRBs in total). That is, the eNB can include two PRB clusters each including M PRBs in the resource block pool for the PSCCH.

Next, a method for specifying a resource pool for PSSCH will be described. In the case of Scheduled resource allocation (sidelink transmission mode 1), the eNB specifies a subframe pool for PSSCH by SIB 18 or dedicated signaling (RRC signaling). The side link control period (PSCCH period) associated with the PSCCH resource setting is further associated with the PSSCH resource setting. The UE determines a PSSCH resource pool composed of subframe pools as follows. That is, as shown in FIG. 2, within the side link control period (PSCCH period), each subframe having a subframe index equal to or greater than l ^PSCCH _PSCCH-1 + 1 is a subframe for PSSCH. Belongs to frame pool.

On the other hand, in the case of autonomous resource selection (sidelink transmission mode 2), the eNB specifies a subframe pool and a resource block pool for PSSCH by SIB 18 or dedicated signaling (RRC signaling). The eNB specifies an offset (O ₂ ), a subframe bitmap, and its length (N _B ) to specify a subframe pool.

The offset (O ₂ ) indicates an offset from the subframe index j _begin of the first subframe in the side link control period (PSCCH period). Here, the total number of subframes having a subframe index equal to or greater than j _begin + O ₂ in the PSCCH period is N ′.

The length (N _B ) of the subframe bitmap is 4, 8, 12, 16, 30, 40 or 42 bits. The subframe bitmap indicates that the subframe corresponding to the bit set to “0” is not used for PSSCH transmission, and the subframe corresponding to the bit set to “1” can be used for PSSCH transmission. Show. In normal cases, the length of the subframe bitmap (N _B ) is calculated from the total number of subframes (N ′) having a subframe index equal to or greater than j _begin + O ₂ within the PSCCH period. small. Thus, the UE determines the bitmaps b ₀ , b ₁ , b ₂ , ..., b _N′-1 according to the following formula:

_{Here, a 0, a 1, a} 2, ..., a N_B-1 is a bitmap length N _B designated as PSSCH set by eNB. If b _j = 1, subframe l _j belongs to the subframe pool for PSSCH.

The resource block pool for PSSCH in the case of Autonomous resource selection (sidelink transmission mode 2) is specified in the same way as the resource block pool for PSCCH. That is, the eNB specifies a start (start) Physical Resource 開始 Block (PRB) index (S1), an end (end) PRB index (S2), and the number of PRBs (PSB) in order to identify a resource block pool for PSSCH. M) is specified in the PSSCH resource settings.

Next, the hybrid “automatic” repeat request (HARQ) for PSSCH transmission on the side link will be described. First, the outline of HARQ adopted in 3GPP Release 8 and later will be described. The 3GPP Release 8 and later media access control (MAC) layer employs an incremental redundancy HARQ for downlink and uplink transmissions and basically uses a stop-and-wait (SAW) protocol (mode). To do.

As is well known, HARQ is a scheme in which forward error correction coding such as turbo coding is combined with a primitive ARQ scheme. That is, in HARQ, user data and Cyclic Redundancy Check (CRC) bits are protected by an error correction code (error correcting code (ECC)). The addition of an error correction code increases the probability of successful transmission to HARQ by increasing redundancy, but on the other hand, the ratio of user data in the transmission data decreases (that is, the coding rate decreases). Invite.

For this reason, 3GPP Release 8 and later support incremental redundancy (IR) HARQ. In Incremental redundancy HARQ, the retransmitted data includes additional parity bits different from the initial transmission data (including systematic bits and some parity 一部 bits obtained by turbo coding). For example, in the case of downlink transmission, the eNB manages the circular buffer (circular buffer (CB)) that stores the code block after performing turbo coding, sub-block interleaving, and bit collection, and the first transmission. In order to transmit systematic bits, an offset corresponding to the head of CB (that is, redundancy version (RV) = 0) is used. Redundancy version (RV) defines the starting position when reading bits from the CB for transmission. In retransmission, the eNB selects an RV that is different from the initial transmission for incremental redundancy (IR), thereby transmitting additional parity bits that were not included in the initial transmission.

The Stop-and-wait (SAW) protocol is the most basic retransmission protocol. That is, in the case of downlink transmission, when the eNB transmits one downlink transport block, the eNB stops new transmission and waits until receiving HARQ feedback (ie, ACK or NACK) from the UE. And when positive feedback (ACK) is received from UE, eNB transmits a new downlink transport block. On the other hand, when negative feedback (NACK) is received from the UE (or when a predetermined period has elapsed without receiving feedback), the eNB retransmits the transport block.

However, a simple SAW protocol results in increased latency and increased signaling overhead in poor radio conditions where the transmitter (sender) must attempt many retransmissions. Therefore, Transmit Time Interval (TTI) bundling is further introduced.

TTI is defined as a time length (length （of time (time （length)) in which one transport block and an error detection bit group added thereto are transmitted. The transport block is a data unit (i.e., “MAC Protocol Protocol Data Unit (PDU)) passed from the Medium Access Control (MAC) layer to the physical layer. In the physical layer of the transmitter (sender), the entire transport block is used and calculated to calculate error detection bits (bits), eg Cyclic Redundancy Check (CRC) parity bits. The error detection bit group is added to the transport block. Channel coding in the physical layer is performed on the transport block to which the error detection bit group is added. Further, in the physical layer processing of the transmitter, interleaving is performed on the encoded bit sequence generated from one transport block. Therefore, in order to be able to perform deinterleaving and decoding, the receiver needs to receive at least one TTI data (that is, data corresponding to a transport block to which an error detection bit group is added). There is. The length of the TTI is generally equal to the duration of the subframe (i.e., 1 msec in LTE).

3GPP Release 8 and later have introduced TTI bundling for uplink transmission. When TTI bundling is enabled (activated), instead of waiting for HARQ feedback from the eNB, the UE replaces the same transport block with four different redundancy versions in four consecutive TTIs (ie subframes). Send with. The eNB transmits an ACK when the transport block can be successfully decoded based on transmissions in four consecutive TTIs. Four consecutive TTIs used for transmission of the same transport block are called TTI bundles.

3GPP Release 12 employs a technique similar to TTI bundling in PSSCH transmission on the side link (see, for example, Section 14.1 of Non-Patent Document 2 and Section 5.14 of Non-Patent Document 3). . Specifically, the transmitting terminal transmits the same transport block in four subframes (four TTIs) included in a subframe set used for PSSCH transmission within a certain side link control period.

As described above, in 3GPP Release 12, radio resource allocation (scheduling) for PSSCH transmission on the side link is performed for each side link control period (PSCCH period). That is, in order to perform data transmission (PSSCH transmission) in a subframe pool for PSSCH within a certain side link control period, the transmitting terminal must be in a subframe pool for PSCCH within the side link control period. The PSCCH carrying scheduling allocation information (ie, SCI format 0) must be transmitted in advance. Therefore, when transmission data addressed to the receiving terminal is generated, the transmitting terminal cannot immediately transmit it, and needs to wait for the next side link control period (PSCCH period) to arrive. Transmission delays due to such PSSCH resource allocation constraints may make it difficult to use side link transmissions for applications that demand stringent delay requirements.

This transmission delay may be suppressed by allowing the transmitting terminal to reserve PSSCH resources. For example, the transmitting terminal transmits scheduling allocation information (i.e., SCI format 0) indicating a reserved PSSCH resource in a subframe in a PSCCH subframe pool within a certain side link control period. Then, when transmission data is generated within the side link control period, the transmission terminal transmits this in the reserved PSSCH resource within the side link control period. On the other hand, when transmission data does not occur, the transmitting terminal does not transmit PSSCH in the reserved PSSCH resource within the side link control period.

However, allowing PSSCH resource reservation to the transmitting terminal may cause another problem. That is, the receiving terminal tries to receive PSSCH in the reserved radio resource, and transmits a negative HARQ feedback (NACK) because the transport block cannot be successfully decoded in the reserved radio resource (subframe) for which PSSCH transmission is not performed. May be sent to the terminal. Such wasteful NACK transmission causes waste of side link radio resources.

It should be noted that the above-described useless NACK transmission problem may occur when HARQ feedback is performed from the side link receiving terminal to the side link transmitting terminal. Therefore, this useless NACK transmission problem may occur when a PSSCH resource reservation is granted to a transmitting terminal that performs PSSCH transmission using a technique similar to TTI bundling adopted in 3GPP Release 12. In addition, this wasted NACK transmission problem occurs when a technique similar to TTI bundling is not used, ie when a simple SAW HARQ is performed for sidelink shared channel (SL-SCH) transport block transmission. Can also occur.

One of the objects to be achieved by the embodiments disclosed herein is to contribute to suppressing unnecessary negative feedback transmission from the receiving terminal to the transmitting terminal in D2D transmission (eg, side link transmission). An apparatus, a method, and a program are provided.

In the first aspect, the 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 radio transceiver, and a physical layer and medium for receiving data from a transmitting terminal without going through a base station according to a periodic device-to-device (D2D) control period It is configured to operate as an Access Control (MAC) layer. The at least one processor is configured to receive D2D control information transmitted on a physical control channel from the transmitting terminal within a first D2D control period. The D2D control information indicates that one or a plurality of radio resources within the first D2D control period are designated as reserved radio resources with which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal. Show. Further, the at least one processor is configured to perform a negative operation on a transport block associated with the physical data channel when transmission of the physical data channel from the transmitting terminal in the reserved radio resource is not detected in the physical layer. It is configured not to transmit feedback from the MAC layer to the transmitting terminal.

In a second aspect, a method in a receiving terminal for receiving data from a transmitting terminal without going through a base station according to a periodic device-to-device (D2D) control period,
(A) receiving D2D control information transmitted on a physical control channel from a transmitting terminal within a first D2D control period, wherein the D2D control information is one or more radios within the first D2D control period Indicating that the resource is designated as a reserved radio resource from which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal;
(B) attempting to receive the physical data channel from the transmitting terminal in the reserved radio resource in a physical layer; and (c) if transmission of the physical data channel is not detected in the physical layer, Do not send negative feedback on the transport block associated with the physical data channel from the Medium Access Control (MAC) layer to the sending terminal,
including.

In the third aspect, the 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 transmit data to a receiving terminal without going through a base station according to a periodic device-to-device (D2D) control period. The at least one processor is configured to transmit D2D control information to the receiving terminal on a physical control channel within a first D2D control period. The D2D control information indicates that one or a plurality of radio resources within the first D2D control period are designated as reserved radio resources with which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal. Show. The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback.

In a fourth aspect, a method in a transmitting terminal that transmits data to a receiving terminal without going through a base station according to a periodic device-to-device (D2D) control period includes a physical control channel within the first D2D control period. Transmitting D2D control information to the receiving terminal. The D2D control information indicates that one or a plurality of radio resources within the first D2D control period are designated as reserved radio resources with which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal. Show. The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback.

In a fifth aspect, a base station includes a wireless transceiver configured to communicate with a plurality of wireless terminals in a cell, and at least one processor. The at least one processor is configured to control data transmission from the transmitting terminal to the receiving terminal not through the base station according to a periodic device-to-device (D2D) control period. The at least one processor is configured to notify the transmission terminal of permission to reserve resources for the data transmission. The permission means that when the transmitting terminal transmits D2D control information to the receiving terminal on a physical control channel within a first D2D control period, one or a plurality of radio resources within the first D2D control period are allocated. The transmitting terminal is permitted to designate a reserved radio resource that may transmit a physical data channel from the transmitting terminal to the receiving terminal. The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback.

In a sixth aspect, a method in a base station is configured to control the data transmission from a transmitting terminal to a receiving terminal according to a periodic device-to-device (D2D) control period without controlling the data transmission via the base station. For notifying the transmitting terminal of permission to reserve a resource for. The permission means that when the transmitting terminal transmits D2D control information to the receiving terminal on a physical control channel within a first D2D control period, one or a plurality of radio resources within the first D2D control period are allocated. The transmitting terminal is permitted to designate a reserved radio resource that may transmit a physical data channel from the transmitting terminal to the receiving terminal. The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback.

In the seventh aspect, the program includes a group of instructions (software code) for causing the computer to perform the method according to the second, fourth, or sixth aspect described above when read by the computer.

According to the above-described aspect, it is possible to provide an apparatus, a method, and a program that contribute to suppressing transmission of useless negative feedback from a receiving terminal to a transmitting terminal in D2D transmission (e.g., side link transmission).

It is a figure which shows a side link control period (PSCCH period). It is a figure which shows an example of the PSCCH sub-frame pool and PSSCH sub-frame pool in a side link control period. It is a figure which shows an example of the PSCCH resource block pool in a side link control period. It is a figure which shows the structural example of the radio | wireless communications system which concerns on some embodiment. It is a figure for demonstrating transmission of the scheduling allocation information (PSCCH) and data (PSSCH) by the side link by the radio | wireless terminal (transmission terminal) which concerns on 1st Embodiment. It is a flowchart which shows an example of operation | movement of the radio | wireless terminal (transmission terminal) which concerns on 1st Embodiment. It is a flowchart which shows an example of operation | movement of the radio | wireless terminal (transmission terminal) which concerns on 1st Embodiment. It is a flowchart which shows an example of operation | movement of the radio | wireless terminal (transmission terminal) which concerns on 2nd Embodiment. It is a flowchart which shows an example of operation | movement of the base station which concerns on 2nd Embodiment. It is a block diagram which shows the structural example of the radio | wireless terminal which concerns on some embodiment. It is a block diagram which shows the structural example of the base station which concerns on some embodiment.

Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted as necessary for clarification of the description.

A plurality of embodiments shown below will be described mainly for improvement of ProSe specified in 3GPP Release 12 (LTE-Advanced). However, these embodiments are not limited to LTE-Advanced and its improvements, and may be applied to D2D communication in other mobile communication networks or systems.

<First Embodiment>
FIG. 4 shows configuration examples of wireless communication systems according to some embodiments including this embodiment. Each of the wireless terminals (UE) 1A and 1B includes at least one wireless transceiver, performs cellular communication (101 or 102) with the base station (eNB) 2, and also has a direct interface between terminals (eg, PC5 interface or Side link) 103 is configured to perform D2D communication. The D2D communication includes at least direct communication (ProSe Direct Communication) and may further include direct discovery (eg, ProSe Direct Discovery). The eNB 2 manages the cell 21 and can perform cellular communication (101 and 102) with each of the plurality of UEs 1 using cellular communication technology (eg, Evolved Universal Terrestrial Radio Access (E-UTRA) technology). In the example of FIG. 5, a situation in which a plurality of UEs 1 </ b> A and 1 </ b> B are located in the same cell 21 is illustrated for simplification of explanation, but such an arrangement is merely an example. For example, UE1A may be located in one cell of two adjacent cells managed by different eNB2, and UE1B may be located in the other cell. Alternatively, at least one of UE1A and UE1B may be located outside the coverage by one or a plurality of eNBs 2.

Next, transmission of PSCCH and PSSCH on the side link according to the present embodiment will be described below. The transmitting terminal (eg, UE1A) is configured to perform data transmission to the receiving terminal (eg, UE1B) without going through the eNB2 according to a periodic D2D control period (ie, side link control period (PSCCH period)). Yes. As already described, the side link control period includes a subframe pool for PSCCH (first subframe pool) and a subframe pool for PSSCH (second subframe pool). The subframe pool for _PSCCH consists of L _PSCCH subframes that can be used for transmission of side link control information (SCI) including scheduling allocation information (ie, SCI format 0). On the other hand, the subframe pool for _{PSSCH is} composed of L _PSSCH subframes that can be used for data transmission (PSSCH transmission) according to scheduling allocation information (ie, SCI format 0).

More specifically, the transmitting terminal (eg, UE1A) transmits side link control information (SCI) to the receiving terminal (eg, UE1B) on the physical control channel (ie, PSCCH) within a certain sidelink control period. It is configured to The side link control information (ie, scheduling assignment information (SCI format 0)) is such that one or more radio resources within the side link control period can be transmitted by the transmitting terminal as a physical data channel (ie, PSSCH). This indicates that it is designated as a reserved radio resource with a certain nature.

The transmitting terminal may or may not transmit PSSCH in the reserved radio resource. For example, the transmitting terminal (eg, UE1A) receives side link control information (SCI format 0) including designation of reserved radio resources in one or a plurality of subframes in a PSCCH subframe pool within a certain sidelink control period. When transmission data addressed to the receiving terminal is generated in the side link control period, the data may be transmitted to the receiving terminal on the PSSCH in any reserved radio resource. . On the other hand, if the reserved radio resource is designated as a receiving terminal within a certain side link control period, but no transmission data addressed to the receiving terminal is generated during the side link control period, the transmitting terminal The PSSCH may not be transmitted in any of the reserved radio resources.

In some implementations, a technique similar to TTI bundling may be employed for transmission of SL-SCH transport blocks in PSSCH, similar to 3GPP Release 12. For example, when a transmitting terminal performs PSSCH transmission, the transmitting terminal uses the same transport in four subframes (four TTIs) included in a subframe set used for PSSCH transmission within a certain side link control period. A block may be sent. In this case, the transmitting terminal may specify reserved radio resources in units of four TTIs (four subframes).

Alternatively, in some implementations, a simple SAW-HARQ may be employed for transmission of SL-SCH transport blocks on PSSCH. In this case, the transmitting terminal may specify reserved radio resources in units of one TTI (one subframe).

On the other hand, the MAC layer of the receiving terminal (eg, UE1B) transmits PSCCH from the transmitting terminal (eg, UE1A) in all of one or a plurality of reserved radio resources corresponding to transmission of one SL-SCH transport block. When it is not detected in the physical layer of the receiving terminal, a negative HARQ feedback (NACK) related to the SL-SCH transport block is not transmitted to the transmitting terminal.

In other words, the MAC layer of the receiving terminal (eg, UE1B) does not detect PSSCH transmission from the transmitting terminal in the physical layer in all of one or a plurality of reserved radio resources corresponding to transmission of one SL-SCH transport block. In this case, it is considered that the corresponding SL-SCH transport block has not been transmitted.

That is, the designation of the reserved radio resource in the side link control information by the transmitting terminal is the PSSCH transmission from the transmitting terminal to the receiving terminal in all of one or a plurality of reserved radio resources corresponding to the transmission of one SL-SCH transport block. In the case where the reception terminal is not performed, the receiving terminal is controlled not to transmit the negative HARQ feedback (NACK) related to the SL-SCH transport block.

Note that the MAC layer of the receiving terminal (eg, UE1B) is the SL-SCH transport received on the PSSCH, although PSSCH transmission from the transmitting terminal (eg, UE1A) is detected in the physical layer of the receiving terminal. If the block is not decoded successfully, negative HARQ feedback (NACK) may be transmitted to the transmitting terminal. On the other hand, when the received SL-SCH transport block is successfully decoded, the MAC layer of the receiving terminal (eg, UE1B) may send a positive HARQ feedback (ACK) to the transmitting terminal. .

As understood from the above description, the transmitting terminal according to the present embodiment clearly indicates to the receiving terminal that one or more radio resources are designated as reserved radio resources for PSSCH transmission. Therefore, if no PSSCH transmission is detected in the reserved radio resource, the receiving terminal determines that PSSCH transmission by the transmitting terminal has not been performed, and suppresses NACK transmission related to PSSCH transmission in the reserved radio resource. Therefore, according to the present embodiment, resource reservation for PSSCH transmission can not only reduce data transmission delay due to scheduling for each side link control period (PSCCH period), but also wasteful NACK transmission by the receiving terminal. Can be prevented from increasing.

In some implementations, the transmitting terminal (e.g., UE 1A) may autonomously determine whether to make a resource reservation for PSSCH transmission. For example, in the case of autonomous resource selection (sidelink transmission 送信 mode 2), the transmitting terminal may autonomously determine a reserved radio resource for PSSCH transmission from the resource pool for PSSCH.

Further or alternatively, the transmission terminal (e.g., UE 1A) may be instructed from the eNB 2 whether or not resource reservation for PSSCH transmission is permitted. For example, in the case of Autonomous resource selection (sidelink transmission mode 2), the eNB 2 indicates whether or not resource reservation for PSSCH transmission is permitted in PSCCH resource setting or PSSCH resource setting in SIB18 or RRC signaling. May be notified. In the case of Scheduled resource allocation (sidelink transmission mode 1), eNB2 notifies the transmitting terminal whether or not resource reservation for PSSCH transmission is permitted in sidelink scheduling grant (DCI format 5) Good. Further, the transmission terminal may determine whether or not resource reservation is necessary, and may transmit a resource reservation permission request to the eNB 2 together with the Sidelink BSR.

In some implementations, the receiving terminal may determine whether PSSCH transmission by the transmitting terminal on the reserved radio resource has been detected in the physical layer based on the received power of the reserved radio resource. Specifically, the receiving terminal may determine that PSSCH transmission by the transmitting terminal has not been detected when the reception power of the reserved radio resource is below a predetermined threshold. Conversely, the receiving terminal may determine that PSSCH transmission by the transmitting terminal has been detected when the reception power of the reserved radio resource exceeds a predetermined threshold.

FIG. 5 is a diagram illustrating an example of transmission of PSCCH and PSSCH according to the present embodiment. FIG. 5 also shows an example of transmission of HARQ feedback (ACK / NACK) from the receiving terminal to the transmitting terminal. In the example of FIG. 5, the transmitting terminal (eg, UE1A) transmits the side link control information on the PSCCH in two subframes in the PSCCH subframe pool 511 in the jth side link control period (PSCCH period) 501. (522 and 523). The side link control information 522 and 523 transmitted in the jth side link control period 501 indicates that the radio resources 531 to 534 in the PSSCH subframe pool 512 in the jth side link control period 501 To be designated as a reserved radio resource.

In the example of FIG. 5, the transmitting terminal (e.g., UE 1A) transmits the PSSCH in the radio resource 533 among the four reserved radio resources 531 to 534, and does not transmit the PSSCH in the radio resources 531 532, and 524. The receiving terminal (e.g., UE 1B) attempts to receive PSSCH from the transmitting terminal in all four reserved radio resources 531 to 534. The receiving terminal detects PSSCH transmission from the transmitting terminal in the radio resource 533, and transmits positive or negative HARQ feedback (ACK / NACK) regarding the decoding result of the SL-SCH resource block transmitted by the PSSCH to the transmitting terminal. On the other hand, since the PSSCH transmission from the transmitting terminal is not detected in the radio resources 531, 532, and 524, the receiving terminal does not transmit negative HARQ feedback regarding the transport block associated with these PSSCH transmissions.

In the example of FIG. 5, for transmission of HARQ feedback (ACK / NACK) for PSSCH transmission in the jth side link control period, the PSCCH resource in the next (j + 1) th side link control period is used. In the example of FIG. 5, four reserved radio resources 531 to 534 are associated with four HARQ feedback radio resources 541 to 544. The receiving terminal transmits HARQ feedback in the radio resource 543 associated with the radio resource 533 where the PSSCH transmission is actually performed, but the radio resource associated with the radio resources 531, 532, and 534 where the PSSCH transmission is not performed. 541, 542 and 544 do not transmit HARQ feedback. Thereby, it is possible to suppress transmission of useless HARQ feedback related to PSSCH transmission that was not actually performed from the receiving terminal to the transmitting terminal.

Note that the arrangement of the side link radio resources 541 to 544 for HARQ feedback shown in FIG. 5 is merely an example. For example, the radio resources 541 to 544 for HARQ feedback may be selected from the PSSCH resource pool 514. Alternatively, a radio resource region (resource pool) for HARQ feedback transmission may be defined within the side link control period independently of the resource pool for PSCCH and PSSCH.

In some implementations, the transmitting terminal may include an information element for explicitly designating the side link radio resource for HARQ feedback in the side link control information (SCI format 0) for scheduling assignment. In order to allow multiple UEs 1 (receiving terminals) to simultaneously transmit HARQ feedback in one radio resource (resource block), this implementation is performed in the same manner as the HARQ feedback transmission scheme in PUCCHPUformat 1a, 1b and 3. Time domain spreading using orthogonal spreading codes may be applied to the HARQ feedback transmission according to the form. In this case, the radio resource for HARQ feedback specified by the transmitting terminal may include a spreading code in addition to the subframe and the resource block.

Alternatively, in some implementations, the location of the side link radio resource for HARQ feedback transmission may be defined in association with the radio resource location to which side link control information 521 and 522 indicating scheduling assignment is transmitted. . Thereby, the receiving terminal can derive the radio resource position where HARQ feedback transmission should be performed from the radio resource position from the radio resource position where the side link control information 521 and 522 are transmitted. For example, the (j + 1) th side link control period corresponding to the subframe and the resource block in the PSCCH resource pool of the jth side link control period used for transmission of the side link control information 521 and 522 Subframes and resource blocks may be used for HARQ feedback transmission.

Alternatively, in some implementations, the location of the side link radio resource for HARQ feedback transmission may be defined in association with the location of the radio resource used for PSSCH transmission. Accordingly, the receiving terminal can derive the radio resource position where HARQ feedback transmission should be performed from the radio resource position from the position of the radio resource used for PSSCH transmission. For example, HARQ feedback may be transmitted in radio resources (subframes or subframes and resource blocks) after a predetermined subframe from radio resources 533 used for PSSCH transmission.

FIG. 6 is a flowchart showing an example of operation (process 600) of the transmission terminal (e.g., UE1A) according to this embodiment. In block 601, the transmitting terminal transmits side link control information (SCI) indicating one or a plurality of reserved PSSCH resources to the receiving terminal (e.g., UE1B) in the jth side link control period (PSCCH period). In block 602, when transmission data addressed to the receiving terminal is generated in the jth side link control period (PSCCH period), the transmitting terminal sets a PSSCH carrying 1 SL-SCH transport block including the transmission data to 1 Or, it is transmitted in any or all of a plurality of reserved PSSCH resources.

FIG. 7 is a flowchart showing an example (processing 700) of the operation of the receiving terminal (e.g., UE1B) according to the present embodiment. In block 701, the receiving terminal receives side link control information (SCI) indicating one or a plurality of reserved PSSCH resources from the transmitting terminal (e.g., UE1A) in the jth side link control period (PSCCH period). In block 702, the receiving terminal attempts to receive PSSCH in each reserved PSSCH resource within the jth side link control period (PSCCH period).

When the PSSCH is received from the transmitting terminal using at least one of one or a plurality of reserved PSSCH resources corresponding to transmission of one SL-SCH transport block (YES in block 703), the receiving terminal transmits the MAC layer of the receiving terminal. Sends positive or negative HARQ feedback to the sending terminal depending on whether the transport block is successfully decoded.

On the other hand, when PSSCH transmission from the transmitting terminal cannot be detected in all of one or a plurality of reserved PSSCH resources corresponding to transmission of one SL-SCH transport block (NO in block 703), the receiving terminal No (negative) HARQ feedback is sent for these one or more reserved radio resources. In other words, in this case, the receiving terminal considers that these one or more reserved radio resources are not used for PSSCH transmission.

<Second Embodiment>
In the present embodiment, a modification of the side link transmission described in the first embodiment will be described. Specifically, a procedure for dynamically changing whether or not the transmission terminal performs resource reservation for PSSCH transmission is described. A configuration example of the wireless communication system according to the present embodiment is the same as that shown in FIG.

As already described, the transmitting terminal (e.g., UE 1A) may autonomously determine whether or not to perform resource reservation for PSSCH transmission. In some implementations, the transmitting terminal may be configured to determine whether to make a resource reservation for PSSCH transmission according to a delay requirement required by the application program. Specifically, the transmission terminal may perform resource reservation for PSSCH transmission when an application that requests strict delay requirements (low delay) is activated or executed in the transmission terminal. As a result, wasteful HARQ feedback related to PSSCH transmission that was not actually performed is transmitted from the receiving terminal to the transmitting terminal while ensuring a state where transmission from the transmitting terminal to the receiving terminal can be performed as soon as transmission data of the application is generated. This can be suppressed.

FIG. 8 is a flowchart showing an example (process 800) of the operation of the transmission terminal according to the present embodiment. In block 801, the transmitting terminal determines whether to make a resource reservation according to the delay requirement required by the application program. When the transmission terminal determines to execute resource reservation, the transmission terminal transmits side link control information (SCI) indicating one or a plurality of reserved PSSCH resources to the reception terminal in each side link control period.

Alternatively, in some implementations, the transmitting terminal (e.g., UE 1A) may be configured to determine whether or not to designate a reserved radio resource according to an instruction from the eNB 2. For example, even if the number of side link transmissions (or the number of side link transmission terminals) performed in the cell 21 of the eNB2 exceeds a predetermined value, the transmission terminal specifies the reserved radio resource according to the instruction from the eNB2. Good. In other words, when the number of side link transmissions performed in the cell 21 exceeds a predetermined value, the eNB 2 may transmit a notification indicating that resource reservation for PSSCH transmission is permitted to the transmission terminal. When resource reservation is not performed, the number of NACK transmissions may increase according to the number of side link transmissions, and when multiple transmission terminals may perform NACK transmission with the same resource, The possibility of collision between NACKs increases. On the other hand, when the transmission number of the side link is large, the eNB 2 causes the transmission terminal to perform resource reservation, thereby suppressing unnecessary NACK transmission and reducing collisions between NACKs. As described above, the eNB 2 may include the resource reservation permission notification in the PSCCH resource setting or the PSSCH resource setting in the SIB18 or RRC signaling, and the resource reservation permission notification may be included in the side link scheduling grant (DCI). It may be included in format IV5).

FIG. 9 is a flowchart showing an example of operation of the eNB 2 (processing 900) according to the present embodiment. In block 901, the eNB 2 detects that the number of side link transmissions (D2D transmissions) performed in the cell 21 exceeds a predetermined value. In block 902, the eNB2 notifies the transmitting terminal that the use of resource reservation for PSSCH transmission is permitted.

<Third Embodiment>
In the present embodiment, a modification of the side link transmission described in the first embodiment will be described. Specifically, a procedure for dynamically determining the number of HARQ feedback radio resources associated with a plurality of reserved radio resources for PSSCH transmission will be described. A configuration example of the wireless communication system according to the present embodiment is the same as that shown in FIG.

The transmitting terminal (eg, UE1A) according to the present embodiment transmits positive or negative HARQ feedback related to the decoding result of the SL-SCH transport block transmitted in the reserved radio resource from the receiving terminal (eg, UE1B) to the transmitting terminal. Therefore, the number of radio resources reserved for this purpose is configured to be adjusted according to the frequency of occurrence of transmission data in the transmission terminal. More specifically, the transmitting terminal may ensure the number of HARQ feedback transmission resources that is equal to or close to the number of reserved radio resources as the transmission data generation frequency increases. On the other hand, the transmission terminal needs to secure a smaller number of HARQ feedback transmission resources compared to the number of reserved radio resources as the transmission data generation frequency decreases.

This will be explained using a specific example. In the example of FIG. 5, four reserved radio resources 531 to 534 are designated in the j-th side link control period 501 and four HARQ feedback radio resources 541 to 544 corresponding to these four reserved radio resources 531 to 534 are designated. Is secured. However, for example, when an application with strict delay requirements but not high data generation frequency is executed at the transmitting terminal, it is necessary to specify a large number of reserved radio resources. Of these reserved radio resources, the actual PSSCH There may be only one or several resources used for transmission. In such a case, assuming that PSSCH transmission is performed with all reserved radio resources, securing radio resources for HQRQ feedback may lead to waste of radio resources.

Therefore, for example, when an application is executed in which the delay requirement is strict but the frequency of data generation per side link control period is about once (1 TTI or 1 subframe), the transmitting terminal is set at a constant interval (for example, 2 msec). A large number of reserved radio resources are specified, but only one or two radio resources may be secured as radio resources for HARQ feedback associated with these reserved radio resources. According to such an operation, waste of radio resources can be suppressed while dynamically securing a necessary number of radio resources for HARQ feedback.

When multiple SL-SCH transport block transmissions (that is, multiple PSSCH transmissions) occur in multiple reserved radio resources, multiple HARQ Fordback radio resources according to the transmission order of SL-SCH transport blocks The order of use may be determined. That is, the receiving terminal transmits a plurality of HARQ feedbacks related to the received plurality of SL-SCH transport blocks in a plurality of HARQ radio resources determined based on the transmission order (reception order) of the plurality of SL-SCH transport blocks. do it.

Finally, a configuration example of the UE 1 according to the above-described plurality of embodiments will be described. FIG. 10 is a block diagram illustrating a configuration example of UE1. Both UE1 as the transmission terminal and UE1 as the reception terminal described above may have the configuration shown in FIG. The Radio-Frequency (RF) transceiver 1001 performs analog RF signal processing in order to communicate with the eNB 2. Analog RF signal processing performed by the RF transceiver 1001 includes frequency up-conversion, frequency down-conversion, and amplification. RF transceiver 1001 is coupled to antenna 1002 and baseband processor 1003. That is, the RF transceiver 1001 receives modulation symbol data (or OFDM symbol data) from the baseband processor 1003, generates a transmission RF signal, and supplies the transmission RF signal to the antenna 1002. Further, the RF transceiver 1001 generates a baseband received signal based on the received RF signal received by the antenna 1002 and supplies this to the baseband processor 1003.

The baseband processor 1003 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Digital baseband signal processing consists of (a) data compression / decompression, (b) data segmentation / concatenation, (c) 生成 transmission format (transmission frame) generation / decomposition, and (d) transmission path encoding / decoding. , (E) modulation (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 layer 1 (eg, transmission power control), layer 2 (eg, radio resource management, hybrid automatic repeat request (HARQ) processing), and layer 3 (eg, attach, mobility, and call management). Communication management).

For example, in the case of LTE and LTE-Advanced, the digital baseband signal processing by the baseband processor 1003 includes signal processing of Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, MAC layer, and PHY layer. But you can. The control plane processing by the baseband processor 1003 may include Non-Access 処理 Stratum (NAS) protocol, RRC protocol, and MAC CE processing.

The baseband processor 1003 includes a modem processor (eg, Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (eg, Central Processing Unit (CPU) that performs control plane processing, or Micro Processing Unit. (MPU)). In this case, a protocol stack processor that performs control plane processing may be shared with an application processor 1004 described later.

Application processor 1004 is also called a CPU, MPU, microprocessor, or processor core. The application processor 1004 may include a plurality of processors (a plurality of processor cores). The application processor 1004 is a system software program (Operating System (OS)) read from the memory 1006 or a memory (not shown) and various application programs (for example, call application, web browser, mailer, camera operation application, music playback) Various functions of UE1 are realized by executing (application).

In some implementations, the baseband processor 1003 and the application processor 1004 may be integrated on a single chip, as indicated by the dashed line (1005) in FIG. In other words, the baseband processor 1003 and the application processor 1004 may be implemented as one System on Chip (SoC) device 1005. An SoC device is sometimes called a system Large Scale Integration (LSI) or chipset.

The memory 1006 is a volatile memory, a nonvolatile memory, or a combination thereof. The memory 1006 may include a plurality of physically independent memory devices. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is a mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, hard disk drive, or any combination thereof. For example, the memory 1006 may include an external memory device accessible from the baseband processor 1003, the application processor 1004, and the SoC 1005. The memory 1006 may include a built-in memory device integrated within the baseband processor 1003, the application processor 1004, or the SoC 1005. Further, the memory 1006 may include a memory in a Universal Integrated Circuit Card (UICC).

The memory 1006 may store a software module (computer program) including an instruction group and data for performing processing by the UE 1 described in the above-described plurality of embodiments. In some implementations, the baseband processor 1003 or the application processor 1004 may be configured to perform the processing of the UE 1 described in the above-described embodiment by reading the software module from the memory 1006 and executing the software module.

FIG. 11 is a block diagram illustrating a configuration example of the base station (eNB) 2 according to the above-described embodiment. Referring to FIG. 11, the base station 2 includes an RF transceiver 1101, a network interface 1103, a processor 1104, and a memory 1105. The RF transceiver 1101 performs analog RF signal processing to communicate with the wireless terminal 1. The RF transceiver 1101 may include multiple transceivers. RF transceiver 1101 is coupled to antenna 1102 and processor 1104. The RF transceiver 1101 receives modulation symbol data (or OFDM symbol data) from the processor 1104, generates a transmission RF signal, and supplies the transmission RF signal to the antenna 1102. Further, the RF transceiver 1101 generates a baseband received signal based on the received RF signal received by the antenna 1102 and supplies this to the processor 1104.

The network interface 1103 is used to communicate with network nodes (e.g., Mobility Management Entity (MME) and Serving Gateway (S-GW)). The network interface 1103 may include, for example, a network interface card (NIC) compliant with IEEE 802.3 series.

The processor 1104 performs digital baseband signal processing (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 by the processor 1104 may include signal processing of a PDCP layer, an RLC layer, a MAC layer, and a PHY layer. Further, the control plane processing by the processor 1104 may include S1 protocol, RRC protocol, and MAC-CE processing.

The processor 1104 may include a plurality of processors. For example, the processor 1104 may include a modem processor (e.g., DSP) that performs digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) that performs control plane processing.

The memory 1105 is configured by a combination of a volatile memory and a nonvolatile memory. The volatile memory is, for example, SRAM or DRAM or a combination thereof. The non-volatile memory is, for example, an MROM, PROM, flash memory, hard disk drive, or a combination thereof. Memory 1105 may include storage located remotely from processor 1104. In this case, the processor 1104 may access the memory 1105 via the network interface 1103 or an I / O interface not shown.

The memory 1105 may store a software module (computer program) including an instruction group and data for performing processing by the base station 2 described in the above embodiments. In some implementations, the processor 1104 may be configured to perform the processing of the base station 2 described in the above-described embodiment by reading the software module from the memory 1105 and executing the software module.

As described with reference to FIGS. 10 and 11, each of the processors included in the UE 1 and the eNB 2 according to the above-described embodiment includes an instruction group for causing a computer to execute the algorithm described with reference to the drawings. Run multiple programs. The program can be stored and supplied to a computer using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media (tangible storage medium). Examples of non-transitory computer-readable media are magnetic recording media (eg flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (eg magneto-optical discs), Compact Disc Read Only Memory (CD-ROM), CD-ROM R, CD-R / W, semiconductor memory (for example, mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM)). The program may also be supplied to the computer by various types of temporary computer-readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

<Other embodiments>
The above-described embodiments may be implemented independently or may be implemented in combination as appropriate.

The embodiment described above is not limited to LTE-Advanced IV and its improvements, but may be applied to D2D communication in other mobile communication networks or systems.

Furthermore, the above-described embodiments are merely examples relating to application of the technical idea obtained by the present inventors. That is, the technical idea is not limited to the above-described embodiment, and various changes can be made.

This application claims priority based on Japanese Patent Application No. 2015-149321 filed on July 29, 2015, the entire disclosure of which is incorporated herein.

1 UE
2 eNB
1001 radio frequency (RF) transceiver 1003 baseband processor 1004 application processor 1006 memory 1101 RF transceiver 1104 processor 1105 memory

Claims (26)

1. A receiving terminal,
   At least one wireless transceiver;
   As a physical layer and a medium access control (MAC) layer coupled to the at least one wireless transceiver, for receiving data from a transmitting terminal without going through a base station according to a periodic device-to-device (D2D) control period At least one processor configured to operate;
   With
   The at least one processor is configured to receive D2D control information transmitted on the physical control channel from the transmitting terminal within a first D2D control period, and the D2D control information is the first D2D control period. One or more of the radio resources are designated as reserved radio resources from which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal;
   The at least one processor may provide negative feedback regarding a transport block associated with the physical data channel when transmission of the physical data channel from the transmitting terminal on the reserved radio resource is not detected in the physical layer. Is configured not to transmit to the transmitting terminal from the MAC layer,
   Receiving terminal.
2. The at least one processor has detected transmission of the physical data channel from the transmitting terminal in the reserved radio resource in the physical layer, but the transport block received on the physical data channel is the MAC layer Configured to transmit the negative feedback to the transmitting terminal if not successfully decoded at
   The receiving terminal according to claim 1.
3. The at least one processor is configured to determine whether transmission of the physical data channel is detected in the physical layer based on received power of the one or more radio resources;
   The receiving terminal according to claim 1 or 2.
4. The at least one processor is configured to determine that transmission of the physical data channel is not detected in the physical layer when the received power is below a predetermined value;
   The receiving terminal according to claim 3.
5. Each D2D control period includes a first subframe pool composed of a plurality of subframes usable for transmission of the physical control channel, and the physical data according to the D2D control information transmitted on the physical control channel. Including a second subframe pool of subframes usable for transmission of the channel;
   The receiving terminal according to any one of claims 1 to 4.
6. A method in a receiving terminal for receiving data from a transmitting terminal without going through a base station according to a periodic device-to-device (D2D) control period,
   Receiving D2D control information transmitted on a physical control channel from a transmitting terminal within a first D2D control period; the D2D control information includes one or more radio resources within the first D2D control period; Indicates that a physical data channel is designated as a reserved radio resource that may be transmitted from the transmitting terminal to the receiving terminal;
   Attempting to receive at the physical layer the physical data channel from the transmitting terminal on the reserved radio resource; and if transmission of the physical data channel is not detected at the physical layer, associated with the physical data channel. Do not send negative feedback on the transport block from the Medium Access Control (MAC) layer to the sending terminal,
   A method comprising:
7. When transmission of the physical data channel from the transmitting terminal in the reserved radio resource is detected in the physical layer, but the transport block received on the physical data channel is not successfully decoded in the MAC layer, Further comprising transmitting the negative feedback to the transmitting terminal;
   The method of claim 6.
8. Further comprising determining whether transmission of the physical data channel is detected in the physical layer based on received power of the one or more radio resources;
   The method according to claim 6 or 7.
9. A non-transitory computer-readable medium storing a program for causing a computer to perform a method in a receiving terminal for receiving data from a transmitting terminal without going through a base station according to a periodic device-to-device (D2D) control period There,
   The method
   Receiving D2D control information transmitted on a physical control channel from a transmitting terminal within a first D2D control period; the D2D control information includes one or more radio resources within the first D2D control period; Indicates that a physical data channel is designated as a reserved radio resource that may be transmitted from the transmitting terminal to the receiving terminal;
   Attempting to receive at the physical layer the physical data channel from the transmitting terminal on the reserved radio resource; and if transmission of the physical data channel is not detected at the physical layer, associated with the physical data channel. Do not send negative feedback on the transport block from the Medium Access Control (MAC) layer to the sending terminal,
   Comprising
   A non-transitory computer readable medium.
10. A sending terminal,
    At least one wireless transceiver;
    At least one processor coupled to the at least one wireless transceiver and configured to transmit data to a receiving terminal without going through a base station according to a periodic device-to-device (D2D) control period;
    With
    The at least one processor is configured to transmit D2D control information to the receiving terminal on a physical control channel within a first D2D control period;
    The D2D control information indicates that one or a plurality of radio resources within the first D2D control period are designated as reserved radio resources with which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal. Show
    The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback,
    Sending terminal.
11. In the designation of the reserved radio resource by the D2D control information, the physical data channel is transmitted from the transmitting terminal in the reserved radio resource, but the transport block received on the physical data channel is Controlling the receiving terminal to transmit the negative feedback to the transmitting terminal if not successfully decoded at the receiving terminal;
    The transmission terminal according to claim 10.
12. The at least one processor is configured to determine whether to designate the reserved radio resource according to a delay requirement required by an application program;
    The transmission terminal according to claim 10 or 11.
13. The at least one processor is configured to determine whether to designate the reserved radio resource according to an instruction from the base station;
    The transmitting terminal according to any one of claims 10 to 12.
14. The at least one processor is configured to specify the reserved radio resource according to an instruction from the base station when the number of D2D transmissions performed in a cell of the base station exceeds a predetermined value.
    The transmitting terminal according to any one of claims 10 to 12.
15. The reserved radio resource includes a plurality of radio resources,
    The at least one processor determines the number of radio resources reserved for transmitting positive or negative feedback regarding a transport block transmitted in the reserved radio resource from the receiving terminal to the transmitting terminal. It is configured to adjust according to the frequency of transmission data,
    The transmitting terminal according to any one of claims 10 to 14.
16. A method in a transmitting terminal for transmitting data to a receiving terminal without going through a base station according to a periodic device-to-device (D2D) control period,
    Transmitting D2D control information to the receiving terminal on a physical control channel within a first D2D control period;
    The D2D control information indicates that one or a plurality of radio resources within the first D2D control period are designated as reserved radio resources with which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal. Show
    The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback,
    Method.
17. In the designation of the reserved radio resource by the D2D control information, the physical data channel is transmitted from the transmitting terminal in the reserved radio resource, but the transport block received on the physical data channel is Controlling the receiving terminal to transmit the negative feedback to the transmitting terminal if not successfully decoded at the receiving terminal;
    The method of claim 16.
18. Further comprising determining whether to designate the reserved radio resource according to a delay requirement required by the application program,
    18. A method according to claim 16 or 17.
19. Further comprising determining whether to designate the reserved radio resource according to an instruction from the base station,
    The method according to any one of claims 16 to 18.
20. When the number of D2D transmissions performed in the cell of the base station exceeds a predetermined value, further comprising designating the reserved radio resource according to an instruction from the base station,
    The method according to any one of claims 16 to 18.
21. The reserved radio resource includes a plurality of radio resources,
    In the method, the number of radio resources reserved for transmitting positive or negative feedback related to a transport block transmitted in the reserved radio resource from the receiving terminal to the transmitting terminal is determined by the number of transmission data in the transmitting terminal. Further comprising adjusting according to the frequency of occurrence,
    The method according to any one of claims 16 to 20.
22. A non-transitory computer-readable medium storing a program for causing a computer to perform a method in a transmitting terminal that transmits data to a receiving terminal without going through a base station according to a periodic device-to-device (D2D) control period There,
    The method comprises transmitting D2D control information to the receiving terminal on a physical control channel within a first D2D control period;
    The D2D control information indicates that one or a plurality of radio resources within the first D2D control period are designated as reserved radio resources with which a physical data channel may be transmitted from the transmitting terminal to the receiving terminal. Show
    The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback,
    A non-transitory computer readable medium.
23. A base station,
    A wireless transceiver configured to communicate with a plurality of wireless terminals in the cell;
    At least one processor configured to control data transmission through the base station from a transmitting terminal to a receiving terminal according to a periodic device-to-device (D2D) control period;
    With
    The at least one processor is configured to notify the transmitting terminal of resource reservation permission for the data transmission;
    The permission means that when the transmitting terminal transmits D2D control information to the receiving terminal on a physical control channel within a first D2D control period, one or a plurality of radio resources within the first D2D control period are allocated. Allowing the transmitting terminal to designate a reserved radio resource from which the physical data channel may be transmitted from the transmitting terminal to the receiving terminal;
    The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback,
    base station.
24. The at least one processor is configured to notify the transmission terminal of permission of the resource reservation when the number of D2D transmissions performed in the cell exceeds a predetermined value;
    The base station according to claim 23.
25. A method in a base station,
    In order to control data transmission from the transmitting terminal to the receiving terminal according to a periodic device-to-device (D2D) control period, the resource reservation permission for the data transmission is given to the transmitting terminal. Prepared to notify,
    The permission means that when the transmitting terminal transmits D2D control information to the receiving terminal on a physical control channel within a first D2D control period, one or a plurality of radio resources within the first D2D control period are allocated. Allowing the transmitting terminal to designate a reserved radio resource from which the physical data channel may be transmitted from the transmitting terminal to the receiving terminal;
    The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback,
    Method.
26. A non-transitory computer-readable medium storing a program for causing a computer to perform a method in a base station,
    The method permits permission of resource reservation for the data transmission in order to control data transmission from the transmitting terminal to the receiving terminal not via the base station according to a periodic device-to-device (D2D) control period. Notifying the transmitting terminal,
    The permission means that when the transmitting terminal transmits D2D control information to the receiving terminal on a physical control channel within a first D2D control period, one or a plurality of radio resources within the first D2D control period are allocated. Allowing the transmitting terminal to designate a reserved radio resource from which the physical data channel may be transmitted from the transmitting terminal to the receiving terminal;
    The designation of the reserved radio resource by the D2D control information is negative for the transport block associated with the physical data channel when transmission of the physical data channel to the receiving terminal is not performed in the reserved radio resource. Control the receiving terminal not to send feedback,
    A non-transitory computer readable medium.

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