KR102251056B1 - Scheme related to resource allocation, discovery and signaling in d2d communications - Google Patents

Abstract

The present disclosure provides a method for allocating a resource of an in-coverage terminal performing D2D communication in a cellular communication system, the method comprising: receiving a D2D grant from a base station through a PDCCH; And an operation of transmitting an SA signal and data in a data region in a scheduling assignment (SA) region of a D2D frame based on the D2D grant, wherein the scheduling grant is implicitly, explicitly or semi-explicitly for data transmission. A method characterized by indicating a resource pattern of a resource is proposed.

Description

Techniques related to resource allocation, discovery, and signaling in D2D systems {SCHEME RELATED TO RESOURCE ALLOCATION, DISCOVERY AND SIGNALING IN D2D COMMUNICATIONS}

The present disclosure relates to a resource allocation, discovery, and signaling scheme in a D2D network, and to a resource allocation, discovery, and signaling scheme in a D2D system based on an LTE network.

In the LTE (Long Term Evolution) system, a base station (eNB) dynamically allocates resources on a subframe basis to a user equipment (UE). When semi-persistent scheduling (SPS) is activated, the UE is granted to periodically use resources allocated based on a predetermined configuration until the semi-persistent scheduling is released.

1 is a diagram illustrating an LTE network-based D2D system.

There may be two communication modes in the D2D system in the LTE network. The two modes are an in-coverage D2D communication mode and an out-of-coverage D2D communication mode. In addition, the UE can operate in two modes (ie, mode 1 or mode 2) depending on how resources are allocated. In the mode 1, the base station schedules the corresponding resource for data transmission to the UE. In the mode 2, each UE selects a resource from a resource pool for data transmission. Thus, the in-coverage UE can operate in both modes. That is, the in-coverage UE may operate in mode 1 when the base station allocates resources to it, and may operate in mode 2 by directly selecting the resource. The out-of-coverage UE cannot communicate with the base station, so it can operate only in mode 2. The out-of-coverage UE may select a resource by itself from a preset resource pool for data transmission.

UEs 102, 104 and 106 are UEs in in-coverage mode, UEs 112 and 114 are UEs in out-of-coverage mode, and UEs 108 and 110 are UEs in partial in-coverage mode. The UEs 102, 104, and 106 can operate in mode 1 or mode 2, but the UEs 112, 114, 108, and 110 can operate only in mode 2.

In the in-coverage mode, the resources used by the UE 102 to transmit data and control information are directly scheduled by the base station 100. In the out of coverage mode, the resources used by the UE 112 to transmit data and control information are selected by the UE 112 from a resource pool.

2 is a diagram illustrating a structure of a communication frame in a D2D communication system.

The D2D frame 200 may be divided into a scheduling assignment (SA) region 202 and a data region 204. The SA area 202 is an area through which control information is transmitted, and may include a plurality of control units. In each control unit of the SA region 202, the UE may transmit a scheduling assignment (SA) indicating a resource to be used for transmission in the data region 204. The data area 204 usually has a length of dozens of subframes, and may have a length of 40 ms to 160 ms, for example.

11 is a diagram illustrating a D2D system enabling discovery and communication between UEs.

One of the important features in the D2D system is that adjacent UEs (ie, D2D devices) 1105 can discover each other with the aid of the base station 1100 or without the aid of the base station 1100. As shown in FIG. 11, the UE 1105 may discover not only the UE 1110 in a neighboring cell, but also a UE 1115 in the same cell.

12 is a diagram illustrating a structure of a D2D discovery frame in a D2D system.

A specific period 1200 having an arbitrary length in each cell may be periodically allocated for D2D discovery. As illustrated in FIG. 12, one discovery period 1200 may include a plurality of discovery resource units (DRUs) 1210.

One DRU 1210 may occupy one TTI (transmission time interval) 1215 (eg, one subframe) in the time domain, and one or more resource blocks (RBs; resource) in the frequency domain. block)(1220). One DRU 1210 is usually used to transmit a discovery message of one UE, and thus, the size of one DRU may be affected by the size of the discovery message. Referring to FIG. 12, there may be a total of (Nt * Nf) DRUs in each discovery period, and each DRU is based on a TTI index (or time index) nt and a frequency index nf as DRU <nt, nf>. Can be marked. The base station can allocate a DRU used for a specific UE in each discovery period. Alternatively, the UE may randomly select a DRU for transmitting a discovery message.

At this time, it should be noted that UEs transmitting at the same time (TTI) cannot hear each other due to a half-duplex constraint. Accordingly, there is a need for an efficient discovery resource allocation and access mechanism for fast and efficient discovery between D2D UEs.

The resource allocation scheme in LTE cannot be directly applied to D2D communication. Therefore, it is necessary to design a resource allocation mechanism and signaling for an LTE network-based D2D system.

The present disclosure is intended to provide a signaling scheme corresponding to resource allocation based on characteristics of D2D communication.

In addition, the present disclosure provides a flexible resource allocation method for device discovery in a D2D system so as to efficiently solve problems such as half-duplex problems and in-band emission.

The present disclosure provides a method for allocating a resource of an in-coverage terminal performing D2D communication in a cellular communication system, the method comprising: receiving a D2D grant from a base station through a PDCCH; And an operation of transmitting an SA signal and data in a data region in a scheduling assignment (SA) region of a D2D frame based on the D2D grant, wherein the scheduling grant is implicitly, explicitly or semi-explicitly for data transmission. A method characterized by indicating a resource pattern of a resource is proposed.

In addition, the present disclosure provides a method for allocating a resource of an out-of-coverage terminal performing D2D communication in a cellular communication system, comprising: monitoring a scheduling assignment (SA) area and a data area of a D2D frame based on a preset resource pool; Selecting an unused SA unit and a resource pattern in the SA region and the data region; And transmitting an SA signal and data in the selected SA and resource pattern, respectively, wherein the SA signal implicitly or explicitly indicates a resource pattern of a resource for data transmission. .

The present disclosure provides an in-coverage terminal device performing D2D communication in a cellular communication system, the device comprising: receiving a D2D grant from a base station through a PDCCH; Based on the D2D grant, the SA signal and data are transmitted in the SA (scheduling assignment) region of the D2D frame and data in the data region, and the scheduling grant implicitly, explicitly or semi-explicitly is a resource of a resource for data transmission. A device characterized by indicating a pattern is proposed.

The present disclosure provides an out-of-coverage terminal device performing D2D communication in a cellular communication system, the device comprising: monitoring a scheduling assignment (SA) area and a data area of a D2D frame based on a preset resource pool; Selecting an unused SA unit and a resource pattern in the SA area and the data area; It is configured to transmit an SA signal and data in the selected SA and resource pattern, respectively, and the SA signal implicitly or explicitly indicates a resource pattern of a resource for data transmission.

The present disclosure is in a D2D discovery method of a terminal in a cellular communication system, connection pattern information of a discovery resource unit (DRU) pair from a base station, information on the number of transmissions of a discovery message during a unit discovery period, and the DRU pair hopping interval Receiving at least one of the information and discovery resource pool information; Acquiring information on resources allocated for transmission of the discovery message by the base station; And transmitting a discovery message during M discovery periods based on at least one of a DRU hopping rule and a DRU pair hopping rule, wherein the DRU hopping is used in each of the discovery periods, and the DRU pair hopping Proposes a method characterized in that it is used once in the M discovery periods.

According to the present disclosure, it is possible to implement resource allocation signaling that enables efficient and various resource allocation for a D2D terminal and provides flexibility.

In addition, the D2D discovery resource allocation method according to the present disclosure enables adjacent UEs to discover each other as quickly as possible and discover as many UEs as possible.

1 is a diagram illustrating an LTE network-based D2D system;
2 is a diagram illustrating a structure of a communication frame in a D2D communication system;
3 is a diagram illustrating a resource pattern design of the present disclosure;
4 is a diagram illustrating semi-explicit signaling resource allocation of the present disclosure;
5 is a diagram illustrating a resource allocation and signaling procedure in a D2D system according to an embodiment of the present invention;
6 is a diagram illustrating a method of obtaining and transmitting SA/RPT information of an in-coverage mode 1 D2D transmitting UE according to the present disclosure;
7 is a diagram illustrating a method of obtaining and transmitting SA/RPT information by an out-of-coverage D2D transmitting UE according to the present disclosure with the help of an in-coverage UE;
8 is a diagram illustrating an operation of a D2D receiving UE according to the present disclosure;
9 is an exemplary diagram of resource allocation for solving a half-duplex problem according to an embodiment of the present disclosure;
10 is a diagram illustrating a configuration of a D2D UE device of the present disclosure;
11 is a diagram illustrating a D2D system enabling discovery and communication between UEs;
12 is a diagram illustrating a structure of a D2D discovery frame in a D2D system;
13 is a diagram illustrating a time domain RPT in the case of transmission period = 20 and repetition number = 4 in the present disclosure;
14 is an exemplary diagram of SA patterns for avoiding the half-duplex restriction of the present disclosure;
15A and 15B are diagrams illustrating a D2D discovery resource hopping method according to the present disclosure;
16 is a diagram illustrating a D2D discovery resource hopping method when only DRU pair hopping is applied in the present disclosure;
17 is a diagram illustrating a periodic shuffling method for solving a hidden UE problem of the present disclosure;
18 is an exemplary diagram of a cell-specific DRU connection pattern when K=2 of the present disclosure;
19 is another exemplary diagram of a cell-specific DRU connection pattern when K=2 of the present disclosure;
20 is a diagram illustrating a DRU pair connection pattern applied to SA transmission of the present disclosure;
21 is an exemplary diagram of D2D discovery resource hopping to which a hopping pattern is applied in the present disclosure;
22 is an exemplary diagram of a procedure for transmitting an initial diskbury message by receiving a resource allocation from a base station by a UE of the present disclosure;
23 is an exemplary diagram of a discovery resource access procedure when the UE of the present disclosure transmits a discovery message in a next discovery period;
24 is an exemplary diagram illustrating a procedure for receiving a discovery message by a UE of the present disclosure;
25A-25D are exemplary diagrams of connections of two SAs used by one UE in the present disclosure;
26A to 26C are exemplary diagrams of DRU connection patterns when K=3 in the present disclosure;
27 is an exemplary diagram of a method in which an in-coverage UE transmitter operates in mode 1 and mode 2 according to the present disclosure;
28 is an exemplary diagram of a method in which an in-coverage UE receiver operates in different modes of an SA pool or a data pool according to the present disclosure;
FIG. 29 is a diagram illustrating a procedure of an operation in which an in-coverage UE transmitter obtains T-RPT bitmap repetition information when the number of transmission MAC PDUs is set by SIB for mode 1 in the present disclosure;
FIG. 30 is a diagram illustrating a procedure of an operation in which an in-coverage UE receiver acquires T-RPT bitmap repetition information when the number of transmission MAC PDUs is set by SIB for mode 1 in the present disclosure;
31 is a diagram illustrating an operation of a UE when a UE according to the present disclosure receives a D2D grant but does not have data to be transmitted.

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description of the present disclosure, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present disclosure, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present disclosure and may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout the present specification.

Prior to the detailed description of the present disclosure, examples of interpretable meanings for some terms used in the present specification are provided. However, it should be noted that it is not limited to the interpretation examples presented below.

The base station is a subject that communicates with the terminal, and may be referred to as a BS, NodeB (NB), eNodB (eNB), access point (AP), or the like.

A terminal (User Equipment) is a subject that communicates with a base station, and may be referred to as a UE, a mobile station (MS), a mobile equipment (ME), a device, a terminal, and the like.

The D2D frame may be transmitted through UL resources among LTE resources.

The purpose of the D2D communication of the LTE network is to enable broadcast communication between user equipments (UEs). In D2D communication, the UE is not specified or clearly controlled in resource allocation. Transmission of control information and data between UEs is a one-way transmission without feedback for data broadcasting.

Referring to FIGS. 1 and 2, an overall procedure of a UE within coverage will be described as follows.

1) The D2D resource pool for control information and data transmission of the D2D UE 102 may be scheduled by the base station 100 through a broadcast channel (BCH).

2) The base station 100 transmits a D2D_Grant (D2D_Grant) for SA and/or data to the D2D UE 102. The D2D UE 102 transmits the SA in the SA resource allocated by the base station 100, and then transmits data in the data transmission resource allocated by the base station 100.

3) The D2D UEs 104 and 106 read the SAs in the SA area 202 and check whether a target ID matches them. If the target ID of the SA matches the D2D UEs 104 and 106, the D2D UEs 104 and 106 implicitly or explicitly receive data from a resource linked to the SA. .

Referring to FIGS. 1 and 2, an overall procedure of a UE other than coverage will be described as follows.

1) The D2D resource pool for control information and data may be set in advance.

2) The D2D UE 112 selects an SA and/or data resource for transmission to the other D2D UE 114 based on the monitoring SA (or data) resource pool. The D2D UE 112 transmits an SA having a target ID intended in the selected SA resource, and then transmits data in the selected data resource.

3) The other D2D UE 114 checks the SA of the SA area 202 to see if there is a target ID matching it. If the target ID of the SA matches the other D2D UE 114, the other D2D UE 114 implicitly or explicitly receives data from the resource linked to the SA.

Referring to FIGS. 1 and 2, the overall procedure of the UE in partial coverage when the SA is not scrambled with the target ID will be described as follows. The scrambling may be, for example, that the SA is masked with a target ID as a check redundancy check (CRC). Optionally, not only the SA but also data may be scrambled and transmitted.

1) A D2D resource pool for control information and data transmission of the first D2D UE 108 may be scheduled by the base station 100 through a broadcast channel (BCH).

2) The base station 100 transmits a D2D_Grant (D2D_Grant) for SA and/or data to the first D2D UE 108. The first D2D UE 108 transmits an SA having an intended target ID in the SA resource allocated by the base station 100, and then transmits data in the data transmission resource allocated by the base station 100.

3) The second D2D UE 110 decodes the SA signal from the first D2D UE 108, and selects an unused SA and data resource for the next SA period. The second D2D UE 110 transmits an SA having an intended target ID in the selected SA resource, and then transmits data in the selected data resource.

4) The neighboring D2D UE checks whether the target ID of the SA matches itself, and if the SA matches itself, it may implicitly or explicitly receive data from the resource linked to the SA.

Referring to FIGS. 1 and 2, the overall procedure of the UE in partial coverage when the SA is scrambled by the target ID will be described as follows.

1) A D2D resource pool for control information and data transmission of the first D2D UE 108 may be scheduled by the base station 100 through the BCH.

2) The base station 100 transmits a D2D_Grant for SA and/or data to the first D2D UE 108. The first D2D UE 108 transmits an SA having an intended target ID in the SA resource allocated by the base station 100, and then transmits data in the data transmission resource allocated by the base station 100.

3) The second D2D UE 110 cannot decode the SA (since the SA has been scrambled with the target ID) and only senses a signal from the first D2D UE 108 to detect an unused SA for the next SA period and Select a data resource. The second D2D UE 110 transmits an SA having an intended target ID in the selected SA resource, and then transmits data in the selected data resource.

4) The neighboring D2D UE checks whether the target ID of the SA matches itself, and if the SA matches itself, it may implicitly receive data from the resource linked to the SA.

Referring to FIGS. 1 and 2, the overall procedure of the UE in partial coverage when the SA is scrambled or not scrambled with a target ID will be described as follows.

1) A D2D resource pool for control information and data transmission of the first D2D UE 108 may be scheduled by the base station 100 through the BCH.

2) The base station 100 transmits a D2D_Grant (D2D_Grant) for SA and/or data to the first D2D UE 108. The first D2D UE 108 transmits an SA having an intended target ID in the SA resource allocated by the base station 100, and then transmits data in the data transmission resource allocated by the base station 100.

3) When the received SA is scrambled, the second D2D UE 110 cannot decode the SA from the first D2D UE 108 and only senses a signal from the first D2D UE 108 Then, unused SA and data resources for the next SA period are selected. The second D2D UE 110 transmits an SA having an intended target ID in the selected SA resource, and then transmits data in the selected data resource. When the received SA is not scrambled, the second D2D UE 110 may decode the SA signal from the first D2D UE 108 and select an unused SA and data resource for the next SA period. The second D2D UE 110 transmits an SA having an intended target ID in the selected SA resource, and then transmits data in the selected data resource.

4) The neighboring D2D UE checks whether the target ID of the SA matches itself, and if the SA matches itself, it may implicitly or explicitly receive data from the resource linked to the SA.

For a scrambled SA, the linkage of the SA and data may be implicit. In order to enable explicit connection of the data to the SA for the scrambled SA, the D2D UE may have an SA-data connection table for receiving the scrambled SA. Based on the scrambled SA reception SA-data connection table, when the D2D UE detects the SA, the D2D UE can know the data resource without decoding the SA and the location of the SA resource. Optionally, the SA signal may include 1-bit information for indicating whether or not the SA is scrambled. The D2D UE can know about the implicit or explicit mapping policy using the 1-bit information, and can accurately find unused data resources.

3 is a diagram illustrating a resource pattern design according to the present disclosure.

A method of designing a resource pattern according to the present disclosure will be described with reference to FIG. 3.

One resource pattern for transmission (RPT) may include a collection of resource units in the time domain and the frequency domain. One RPT may correspond to one resource set. The resource set may have consecutive resource units in the time domain, and the resource units on different time units may have different frequency positions.

One RPT may correspond only to a subset of the resource set. For example, the subset may be a set of periodic resource units in a time domain or a set of continuous resource units in a plurality of time units.

The RPT design may include various patterns supporting different traffic such as voice traffic, burst traffic, ftp (file transfer protocol) traffic, or video stream.

One resource set starts from one resource unit of the first time unit. Resource units in subsequent time units may be derived (determined) by specific rules. For example, the specific rule may be the same as a predetermined frequency hopping pattern. A subset of one resource set may also be derived by time-hopping rules. In the LTE system, one resource unit may be a resource block (RB) or a pair of RBs, and the RB corresponds to a time unit that is one time slot, and the pair of RBs corresponds to a time unit of one subframe. May be applicable.

The relationship between the resource set, the resource subset, and the resource patterns is as shown in FIG. 3.

Each of the two resource sets starts with the resource unit 350 of index #1 and the resource unit 360 of #6 in the first time unit, and resource units 352, 362, 354, and 364) may be determined based on a predetermined frequency hopping pattern. Each resource set may be divided into four resource subsets based on a predetermined timing hopping rule. For example, subsets 304, 306, 308, and 310 of resource set #1 300 may be designed according to a time hopping rule'(period=16, repetition=4)' for periodic resource use. Here, the time hopping rule of “(period=16 and repetition=4)” means that time hopping is performed so that one subset has 4 consecutive subframes for a subframe having a total period of 16. Meanwhile, the subsets 322, 324, 326, and 328 of resource set #6 320 may be designed with a time hopping rule'(period=32, repetition=8)' for continuous resource use.

In addition, it is also possible to create a new RPT by explicitly indicating the resource units to be used. As shown in FIG. 3, a new RPT 302 explicitly indicated for subset 1 of resource set 1 is a timing hopping rule'(set index = 1, subset index = 1, period = 8, repetition = 4)' It can be expressed as Using these preset parameters, various resource patterns may be explicitly indicated.

Similarly, in a D2D system, one resource unit may be one RB, one RB pair, or multiple RB pairs. Accordingly, the resource set information may be jointly determined by the size of the resource unit, the frequency index of the resource unit, and the frequency hopping rule. For time domain RPTs within one resource set, each RPT may be represented by a transmission period, a number of repetitions, and a subset index.

13 is a diagram illustrating a time domain RPT in the case of transmission period = 20 and repetition number = 4 in the present disclosure.

The transmission period defines an interval between transmissions for a plurality of medium access control (MAC) protocol data units (PDUs), the number of repetitions is the number of transmissions per MAC PDU, and each transmission per MAC PDU is an initial transmission. It can be an iterative or redundant version of. The subset index is a predefined index to indicate resources to be used.

Next, a resource allocation signaling method of the present disclosure will be described.

The resource allocation signaling method may include 1) implicit signaling, 2) explicit signaling, and 3) semi-explicit signaling.

First, we describe implicit signaling.

In the implicit signaling method, each SA may be directly linked to one or more resource patterns. The connection rule may be set in advance or may be set in advance by the network.

A possible connection rule is that each SA is connected to one predetermined RPT (ie, resource subset). If there are L x K SAs (when the SA region spans L time units and K frequency units), SA(l,k), which is an SA of time unit l and frequency index k, is the k-th resource set. It may be connected to the l-th subset (ie, a predetermined RPT #kl).

For example, in FIG. 3, SA1 340 is connected to a predetermined RPT #1-1 (subset 1 of resource set 1), and SA2 342 is a predetermined RPT #1-2 (subset 2 of resource set 1). ). In this way, the number of time slots (L) of the SA region may be equal to the number of subsets of one resource set (ie, the number of resource patterns of one resource set). In total, there are L x K resource patterns, each of which is connected to an SA. When the base station signals the scheduling grant to the UE, it is only required to indicate the index of the SA, and the resource pattern may be implicitly connected to the UE. The index of the SA may be indicated based on a predetermined indexing rule. For example, in the indexing rule, SA indexes are numbered in order or a frequency index and a time index are combined.

Second, explicit signaling is described.

In the explicit signaling method, resources to be used are explicitly indicated, and resources for SA and data may be indicated separately. At this time, there is no connection between SA and RPT. For example, in FIG. 3, SA1 340 may be indicated for SA transmission, and pre-defined RPT #6-1 may be indicated for data transmission. For more flexible use of resources, it is possible for the base station to explicitly indicate a new RPT to be used instead of indicating a predetermined resource pattern. As described above, the base station explicitly specifies a new RPT having different parameters, such as'(RPT #6-1: Set Index=6, Subset Index=1, Period=20, Repetition=4)'. Can be directed by.

Third, anti-explicit signaling is described.

))의 사용에만 제한되는 것이다. 예를 들어, 도 3에서 SA1(340), SA2(342), SA3(344), SA4(346)는 단지 첫 번째 자원 셋의 RPT들에만 사용되도록 제한된다. SA 그랜트를 얻은 후에, 상기 UE는 사용 가능한 RPT를 알 수 있다. 정확한 자원 사용에 관한 추가적 정보는 데이터 그랜트에서 지시될 수 있다. 셋의 인덱스는 SA에 의해 암시적으로 지시될 수 있으므로, (미리 정해진 RPT를 사용한다면) 상기 데이터 그랜트는 서브셋 인덱스(예를 들어, Subset Index=2)를 지시할 필요만 있다. 또는 상기 데이터 그랜트는 새로운 타임 호핑 룰 ‘(Period=20, Repetition=6)’을 갖는 새로운 파라메터(예를 들어, Subset Index=2)의 RPT를 명시적으로 지시할 수도 있다. 같은 개수의 비트들을 사용함으로써, 반명시적 시그널링 방법은 명시적 시그널링보다 유연한 자원 지시를 달성할 수 있는데, 모든 자원 패턴 대신에 제한된 개수의 자원 패턴으로부터의 자원 사용을 지시할 필요만 있기 때문이다.In the semi-explicit signaling method, a limited number of SAs may be connected to a limited number of resource patterns. One possible method is, when predetermined RPTs are used, SA( l , k ) of time unit l at frequency index k is only RPTs at resource set k (e.g., RPT #kn (

It is limited only to the use of )). For example, in FIG. 3, SA1 340, SA2 342, SA3 344, and SA4 346 are limited to be used only for RPTs of the first resource set. After obtaining the SA grant, the UE can know the available RPT. Additional information regarding the correct resource usage may be indicated in the data grant. Since the index of the set can be implicitly indicated by the SA, the data grant only needs to indicate a subset index (eg, Subset Index=2) (if a predetermined RPT is used). Alternatively, the data grant may explicitly indicate the RPT of a new parameter (eg, Subset Index=2) having a new time hopping rule'(Period=20, Repetition=6)'. By using the same number of bits, the semi-explicit signaling method can achieve more flexible resource indication than explicit signaling, because it is only necessary to indicate the use of resources from a limited number of resource patterns instead of all resource patterns.

4 is a diagram illustrating semi-explicit signaling resource allocation according to the present disclosure.

A more detailed example of semi-explicit signaling is shown in FIG. 4.

The two SAs 410 and 412 at the top of the SA region are connected to resource set 1. In the first D2D frame, one SA 400 corresponding to the entire resource set is granted. In the second D2D frame, two SAs 410 and 420 are granted, each corresponding to one resource subset.

))을 사용하는 데에만 제한되는 것이다.Another possible semi-explicit signaling method is RPTs in which SA( l , k ) in time unit l and frequency index k correspond to subset l of each resource set (i.e., predetermined RPT #ml (

)).

The above-described signaling method explicitly or implicitly indicates an RPT subset index for data transmission in the time domain together with a period value and a repetition value. Alternatively, a bitmap-based method can be used to explicitly indicate the resource subset to be used. In general, a bitmap (N,k) has a length of N bits. Among the N bits, k bits are '1' and the rest are '0'. The bitmap (N,k) means that k subframes indicated (indicated by '1' in bits) among N subframes are used for data transmission. For example, a bitmap of '11110000' (N=8, k=4) means that the first four subframes (subframes 0, 1, 2, 3 indicated by '1' in the bitmap) are used. do. For example, if the bitmap is repeated twice, such as '11110000 11110000', subframes 0, 1, 2, 3 and subframes 8, 9, 10, and 11 will be used. Accordingly, a combination of the basis bitmap ( RPT _ Bitmap _ ID ) and the number of bitmap repetitions ( RPT _ Bitmap _ Repetition _ Num ) may be used to indicate the RPT in the time domain. By indicating the number of bitmap repetitions, the transmitter and the receiver can obtain the number of subframes allowed for data transmission, thus enabling efficient resource utilization.

A frequency hopping method of the present disclosure will be described.

In general, the frequency hopping method (both Type 1 and Type 2) used in the LTE system can be reused for D2D communication. A 1-bit hopping flag may be used to indicate whether frequency hopping is used or not. And, 1 bit or 2 bits (similar to the N_UL_hop parameter of the LTE system, depending on the bandwidth) may be used to indicate the specific hopping type and parameters. For Mode 1 communication of the D2D system, most parameters used in the LTE system can be reused. For Mode 2 communication of the D2D system, some of the parameters used in the LTE system and some of the hopping rules need to be modified.

개의 자원 블록을 갖는다고 가정한다. 상기 Type 2의 미리 정해진 호핑 패턴이 먼저 설명된다.Frequency resources in the D2D resource pool are contiguous

Assume that you have 2 resource blocks. The type 2 predetermined hopping pattern will be described first.

_{The frequency hopping pattern used for transmission of the time slot n s} in the data region of the D2D frame may be given by a scheduling grant having a predetermined pattern according to the following equation. Here, the slot number n _s is defined as a slot number that is continuously re-indexed in the D2D resource pool. Similar to the current LTE system, the slot number can be obtained from a modulo 20 (moudulo-20) operation.

는 D2D PUSCH(Physical uplink shared channel)에서 할당된 RB의 인덱스이며, 상기 스케줄링 그랜트 및 D2D 대역폭 파라메터로부터 획득될 수 있다. 각 서브 밴드의 사이즈

는 다음 수학식으로 주어질 수 있다.here,

Is an index of an RB allocated in a D2D physical uplink shared channel (PUSCH), and may be obtained from the scheduling grant and a D2D bandwidth parameter. Size of each subband

Can be given by the following equation.

는 상위 계층 시그널링에 의해 주어질 수 있고, 상기 D2D 대역폭

는 시스템 정보로부터 획득될 수도 있다. 상기

의 값은 1 또는 2 또는 4일 수 있다(즉, {1, 2, 4}). 상위 계층 시그널링에 의해 제공되는 파라메터 ‘D2D - Hopping - mode’는 호핑이 서브프레임간(inter-subframe) 호핑인지 서브프레임내/서브프레임간(intra/inter-subframe) 호핑인지 결정한다. 각 시간 슬롯에서, 함수

는 호핑 넘버를 결정하고, 함수

는 미러링이 사용되는지 아닌지를 결정한다. 상기 함수들은 다음과 같이 주어질 수 있다.Here, the number of subbands

May be given by higher layer signaling, and the D2D bandwidth

May be obtained from system information. remind

The value of may be 1 or 2 or 4 (ie {1, 2, 4}). Parameters provided by the higher layer signaling 'D2D - Hopping - mode' determines whether the sub-frame hopping between (inter-subframe) that the subframe hopping / sub-frame between the (intra / inter-subframe) hopping. In each time slot, the function

Determines the hopping number, and the function

Determines whether mirroring is used or not. The above functions can be given as follows.

및 랜덤 시퀀스(pseudo-random sequence)

는 3GPP TS(Technical Specification) 36.211 의 7.2절에 의해 결정될 수 있다. ‘CURRENT_TX_NB’는 시간 슬롯 n_s 에 전송되는 전송 블록의 전송 넘버를 지시한다. 그러나, ‘CURRENT_TX_NB’를 D2D에 특정적(specific)이고 같은 D2D 자원 풀을 사용하는 모든 UE들에게 공통(common)하게 만들기 위해, 상기 ‘CURRENT_TX_NB’는 상기 D2D 자원 풀 내의 서브프레임 인덱스로 설정될 수 있다. 상기 랜덤 시퀀스의 생성기는

에 의해 초기화될 수 있다.here,

And a pseudo-random sequence

May be determined by Section 7.2 of 3GPP Technical Specification (TS) 36.211. 'CURRENT_TX_NB' is time slot n _s Indicate the transmission number of the transport block transmitted to. However, in order to make'CURRENT_TX_NB' D2D specific and common to all UEs using the same D2D resource pool, the'CURRENT_TX_NB' may be set as a subframe index in the D2D resource pool. have. The generator of the random sequence is

Can be initialized by

은 고정된 값이거나 또는 커버리지외 통신을 위해 미리 설정될 수 있는데(예를 들어,

의 값은 ‘510’ 과 같이 고정될 수 있음), 커버리지외 통신에서 UE들은 어떤 셀에도 위치하고 있지 않기 때문이다. 커버리지내(in-coverage) 경우라 할지라도, 호핑 패턴을 간단하게 하기 위해 일부 파라미터는 미리 설정될 수 있다. 예를 들어, 항상 서브프레임간 호핑(inter-subframe hopping) 등을 사용하도록 미리 설정될 수 있다.For out-of-coverage communication, a parameter provided by an upper layer may be preset for a frequency hopping pattern. For example,

Is a fixed value or can be preset for out-of-coverage communication (e.g.,

This is because UEs are not located in any cell in out-of-coverage communication. Even in the in-coverage case, some parameters may be preset to simplify the hopping pattern. For example, it may be preset to always use inter-subframe hopping.

The Type 1 hopping pattern can be described as follows.

에 대해, 서브프레임 i에서 할당된 RB 인덱스는 다음과 같이 획득될 수 있다.For convenience of explanation, it is assumed that only inter-subframe hopping is used. That is, it is assumed that intra-subframe hopping is not used. Given RB index

For, the RB index allocated in subframe i may be obtained as follows.

Here, a=1/2, or 1/4, or -1/4, and may be indicated by N_UL_hop. Similarly, in the case of out of coverage, the parameter a may be fixed or may be selected from a preset set.

When the frequency resources of the D2D resource pool are not adjacent, the hopping rules for Type 1 and Type 2 may be slightly different.

의 길이를 갖고 다른 하나의 RB 그룹은

의 길이를 갖는다.

와 같이 설정하여 단일 캐리어 특성이 항상 보장된다면 즉, RB들이 서로 다른 RB 그룹으로 분리되지 않는다면, 상기 Type 1 및 Type 2 호핑은 바로 사용될 수 있다. 그렇지 않다면, 호핑은 각각의 그룹 내에서 존재한다. 즉, 하나의 RB 그룹에는

를 설정하고, 다른 하나의 RB 그룹에는

를 설정한다.For example, there are two different adjacent RB groups, and one RB group is

The other RB group has a length of

Has a length of

If the single carrier characteristic is always guaranteed by setting as described above, that is, if the RBs are not separated into different RB groups, the Type 1 and Type 2 hopping can be used immediately. Otherwise, hopping exists within each group. In other words, in one RB group

And in the other RB group

Is set.

A method of designing a scheduling grant and scheduling allocation according to the present disclosure will be described.

In LTE, an uplink scheduling grant of downlink control information (DCI format 0) format 0 may be reused for a D2D scheduling grant. The D2D scheduling grant can be differentiated by performing CRC masking with a UE-specific D2D Radio Network Temporary Identifier (RNTI). In addition, the setting of the semi-explicit scheduling may be reused to support semi-persistent D2D data transmission. In the case of semi-permanent scheduling, the UE-specific D2D SPS RNTI may be used for CRC masking.

In Table 1, an example of a DCI format 0 field for a D2D grant is described.

Field Name Length Use in D2D-Grant (D2D RNTI / D2D SPS RNTI) Flag for format0/format1A differentiation One Merge Both (Assuming Hopping Always Enabled)
00: SA Only
01: Data Only
10: SA-Data linked (Implicit, with Predefined Rule 1)
11: SA-Data linked (Implicit, with Predefined Rule 2) Hopping flag One N_Ulhop 1 (1.4 MHz)
1 (3 MHz)
1 (5 MHz)
2 (10 MHz)
2 (15 MHz)
2 (20 MHz) Hopping Type and Pattern
* For SA Only case above, this field can be used to indicate Explicit or Semi-Explicit signaling Resource block assignment 5 (1.4 MHz)
7 (3 MHz)
7 (5 MHz)
11 (10 MHz)
12 (15 MHz)
13 (20 MHz) PRB Allocation for SA and/or Data
RPT Index (= Set Index + Subset Index)
3+2 (1.4 MHz), 4+3 (3 MHz), 5+2 (5 MHz)
6+5 (10 MHz), 7+5 (15 MHz), 7+6 (20 MHz) MCS and RV 5 May implicitly indicate the number of repetitions per TB
* For SA Only case above, this field can be used to indicate SA repetitions if supported NDI (New Data Indicator) One Reserved CQI request One Reserved TPC for PUSCH 2 Cyclic shift for DM RS 3 UL index (TDD only) 2 Reserved Downlink Assignment Index 2 Reserved

When only explicit signaling is used, SA and data resource allocation are signaled in a single grant.

The DCI format 0 field for the D2D grant when only explicit signaling is used is illustrated in Table 2.

Field Name Length Use in D2D-Grant (D2D RNTI / D2D SPS RNTI) Hopping flag One PUSCH Hopping flag SA Resource block assignment 6 SA Index Data Resource block assignment 5~13 Data RB Index
BW dependent (N_UL_hop included) Data T-RPT Index 7 Time domain RPT index (May use explicit subset index indication or bitmap index indication) Data T-RPT Length (or Number of RPT Bitmap Repetitions) 4 T-RPT length for data transmissions (or number of RPT bitmap repetitions if RPT bitmap is used) TPC for PUSCH One Power control indication MCS and RV May not used or optionally used due to the size limit of DCI format 0




NDI (New Data Indicator) CQI request Cyclic shift for DM RS UL index (TDD only) Downlink Assignment Index

In this case, some of the fields of the original DCI format 0 may not be used, and due to a size limitation, only a limited number of bits may be used for some of the fields.

If the bit length of some fields is not sufficient to indicate the desired range, higher layer signaling may be used together to achieve an indication of the desired range.

For example, in Table 2, the'SA resource block assignment' field has 6 bits and can indicate only 64 values. If the number of SA indexes is less than 64, the mapping of the SA indexes will be fixed in an explicit indication method. If the number of SA indexes is greater than 64, a problem occurs in indicating all the used SA indexes. In this case, additional bits from the upper layer can be used to extend the index indication. For example, one additional bit may be signaled from an upper layer, and the one bit may be treated as a most significant bit (MSB) bit. Therefore, a total of 7 bits (1 MSB bit + 6 bits) can be used to indicate 128 values. If more bits are signaled to the upper layer, the indicated values will be further extended. This approach can be treated as a method of signaling an SA index offset value from an upper layer, and an exact SA index will be calculated by adding the SA index offset to the 6-bit index value.

Alternatively, the 6 bits indicate only the frequency domain index of the SA, and the time domain index may be signaled to the UE from an upper layer. Alternatively, the SA time domain index may be derived from the UE time when the UE receives the DCI. For example, the SA time domain index may be calculated by adding a preset offset to the UE time at which the UE receives DCI. By combining the SA time domain index and the frequency domain index, an accurate SA index can be obtained.

When the higher layer signaling is not available, it should be guaranteed that the number of SAs belonging to the SA pool is less than 64. The maximum number of SAs in the frequency domain should be considered to set the size of the SA pool in the time domain. Assuming that the number of SAs in the frequency domain is SA_Nf, the number of subframes of the SA in the time domain should be 64/SA_Nf or less.

When a common SA pool is used for mode 1 and mode 2, the first 64 SAs may be configured to be used for mode 1 and the remaining SAs for mode 2. In this way, it is possible to implicitly differentiate (or distinguish) the use of SAs in mode 1 and mode 2.

Another example of a possible indication method using the number of repetitions of the RPT bitmap (' RPT _ Bitmap _ Repetition _ Num' field) will be described.

Option 1 is an explicit indication method. As described in Table 2, if it is possible to include the repetition number parameter of the RPT bitmap ('RPT _ Bitmap _ Repetition _ Num ' field) in the DCI, explicitly indicating the parameter is the most direct method. Otherwise, the number of repetitions of the RPT bitmap may be indicated by higher layer signaling.

Option 2 is an implicit indication method. The number of repetitions of the RPT bitmap may be implicitly indicated. Given a data pool size, the RPT bitmap can be repeated until the end of the data pool. That is, the RPT bitmap can span the entire data pool in the time domain. If the data pool size is not given (for example, only a start time is given), the RPT bitmap may be repeated until the start time of the next SA pool. For example, when the mode 1 SA pool and the mode 2 SA pool are multiplexed in the frequency domain, the mode 1 data RPT bitmap may be repeated until the next mode 1 SA pool (unless there is a problem in conflict with the mode 2 data pool). . Otherwise (i.e., if it can collide with the mode 2 data pool), the mode 1 data RPT bitmap will be repeated up to the mode 2 data pool to avoid collision. When the mode 1 SA pool and the mode 2 SA pool are multiplexed in the time domain, the mode 1 data RPT bitmap may be repeated until the next mode 2 SA pool.

Alternatively, the number of data transmission (or the number of MAC PDUs to be transmitted) may be preset. Four transmissions are used for one MAC PDU, and the RPT bitmap (N, k) is (N=8,k=1), (N=8,k=2), (N=8,k=4) or Suppose you use (N=8,k=8). If two MAC PDUs are set in advance, eight transmissions are required. RPT bitmaps (N=8,k=1), (N=8,k=2), (N=8,k=4) and (N=8,k=8) transmit 8 (2 MACs For PDU), it will repeat 8, 4, 2 and 1 respectively. When at least one MAC PDU is preset to be transmitted, the RPT bitmap (N=8,k=1), (N=8,k=2) and (N=8,k=4) are 4 transmissions (1 MAC PDUs) will repeat 4 times, 2 times and 1 time respectively. The RPT bitmap (N=8,k=8) will repeat once to make 8 transmissions (2 MAC PDUs). This approach is particularly suitable for mode 1 transmission.

Similarly, the SA needs to indicate resource usage for the target UE receiver. An example of the SA field is described in Table 2. In the case of coverage, the information in the D2D grant must be delivered in the SA content. In the case of the D2D SPS grant, a flag for indicating the use of SPS-based resources may be used in the SA. When the SPS flag is enabled, it is assumed that the resource is used persistently-persistently until the resource is released. In case of out of coverage, the SPS indication is also useful because it indicates that the resource is to be used at least in the next transmission interval. Therefore, other UEs wishing to transmit data will know the use of the resource and will not select the resource to avoid transmission collisions.

SA Field Name Length Usage ID N RX (Group) ID and/or TX ID Flag for SA-RPT linkage indication 2 Explicit / Semi-Explicit / Implicit with Predefined Rule 1 / Implicit with Predefined Rule 2 MCS and RV 5 Common for all TBs, and implicitly indicate the number of repetitions per TB Cyclic shift for DM RS 3 For in-coverage UE, same as indicated in D2D-grant
For out-of-coverage UE, following predefine rule Hopping Pattern 1 (1.4 MHz)
1 (3 MHz)
1 (5 MHz)
2 (10 MHz)
2 (15 MHz)
2 (20 MHz) For in-coverage UE, same as indicated in D2D-grant
For out-of-coverage UE, following predefine rule Resource block assignment 5 (1.4 MHz)
7 (3 MHz)
7 (5 MHz)
11 (10 MHz)
12 (15 MHz)
13 (20 MHz) For in-coverage UE, same as indicated in D2D-grant
For out-of-coverage UE, following predefine rule Flag for SPS Indication One SPS or not TX Timing Information 6 Transmit timing information
If UL timing is used, timing advance (TA) value is indicated Mode Indication One Indicate Mode 1 or Mode 2 to receivers Power Information M1 Power information is power control supported Others M2 Reserved

In the case of coverage, the information in the D2D grant must be delivered in the SA content. In the case of a D2D SPS grant, a flag for indicating the use of SPS-based resources “ Flag for SPS Indication ” can be used in SA. When the SPS flag is enabled, it is assumed that the resource is used continuously-persistently until the resource is released.

In case of out of coverage, the SPS indication is also useful because it indicates that the resource is to be used at least in the next transmission interval. Therefore, other UEs wishing to transmit data will know the use of the resource and will not select the resource to avoid transmission collisions.

When a UE in communication mode 1 can transmit data with UL timing (ie, timing advance (TA)), it is necessary to indicate a TA value that enables another UE to receive data at an appropriate timing. In addition, when the SA pooling mode 1 and mode 2 are commonly used, the mode is indicated to the UE receiver (“ Mode Indication ” field) is necessary and useful as well. This is because the data pools of mode 1 and mode 2 are different from each other, and the usage of parameters (eg, hopping parameters for data resource allocation) may also be different. This explicit mode indication may allow the UE to distinguish between a communication mode that causes the receiver to perform an appropriate operation. Alternatively, a specific TA value may be used to distinguish between Mode 1 or Mode 2. For example, a TA value of 0 may be used to indicate the mode 2 case. This is because normal mode 1 UEs have a valid TA value (non-zero value), and mode 2 UEs do not.

In consideration of the case of DCI format 0 in Table 2, corresponding SA contents are described in Table 4.

SA Field Name Length Usage ID N RX (Group) ID and/or TX ID Data Resource block assignment 5~13 Data RB Index
BW dependent (N_UL_hop included) Data T-RPT Index 7 For in-coverage UE, same as indicated in D2D-grant
For out-of-coverage UE, following pre-defined rule Data T-RPT Length (or Number of RPT Bitmap Repetitions) 4 T-RPT length for data transmissions (or number of RPT bitmap repetitions if RPT bitmap is used) MCS and RV 5 Common for all TBs (RV may be pre-fixed) Flag for SPS Indication One SPS or not TX Timing Information 6 Transmit timing information
If UL timing is used, timing advance (TA) value is indicated Mode Indication One Indicate Mode 1 or Mode 2 to receivers Others
M Reserved

Similarly, some parameters, such as, for example, the number of RPT bitmap repetitions, may be implicitly indicated.

5 is a diagram illustrating a resource allocation and signaling procedure in a D2D system according to an embodiment of the present invention.

5 shows a DL spectrum 500 and a UL spectrum 502 as resources that can be used in the LTE system. LTE UL resources may be used for D2D communication, and the UL spectrum 502 may repeatedly include a region 504 and a D2D frame 506 for LTE cellular.

For a UE in coverage, resources for both SA and data are granted by the base station. The UE out of coverage selects a transmission resource by itself, if information of the resource pool is available (eg, delivered by an in-coverage terminal).

As described in Figure 5, UE1, UE2, UE3 and UE4 are in-coverage UEs. On the other hand, UE5 is an out-of-coverage UE.

For UE1, implicit signaling is used, where the base station transmits (510) a single SA-data grant indicating the use of SA1 512 and the connected RPT #1-1 514.

In the case of UE2, explicit signaling is used, and the base station transmits an SA grant indicating the SA resource SA3 (522) (518), and separates a data grant indicating the use of a predetermined RPT #4-1 (524). Can transmit (520).

In the case of UE3, semi-explicit signaling is used, and the base station transmits an SA grant indicating the SA resource SA2 532 (implicitly, indicating the use of resource set 2) (528), and specifies the correct subset index. The data grant that is ultimately instructed is transmitted (530), and finally, the use of RPT #2-2 (534) is instructed.

In the case of UE4, another semi-explicit signaling approach is used, wherein the base station transmits an SA grant indicating the SA resource SA6 546 (implicitly indicating the use of a subset of index 4) (542), and A data grant explicitly indicating the set index is transmitted (544), and finally, the use of RPT #3-4 (548) is instructed.

In the case of UE2, which is an out-of-coverage UE, UE5 may monitor the use of a channel and select an unused SA/RPT for transmission based on implicit signaling. For example, UE5 may select SA5 536 and RPT #4-2 538 as unused SA and RPT, respectively.

6 is a diagram illustrating a method of obtaining and transmitting SA/RPT information of a D2D transmitting UE in coverage according to the present disclosure.

The D2D UE within the coverage may perform a buffer report or make a scheduling request to the base station (600).

The D2D UE checks the PDCCH and checks whether there is a D2D grant (605).

If there is no D2D grant as a result of the check in step 605, the D2D UE may check the PDCCH again.

If there is a D2D grant as a result of the check in step 605, the D2D UE decodes the D2D grant (610).

The D2D UE checks whether the D2D grant is an SA-data combination grant (615).

When the D2D grant is an SA-data combination grant, the D2D UE acquires SA/RPT information (630), transmits data from the granted RPT of the next D2D frame, and transmits the SA (645).

If the D2D grant is not an SA-data combination grant, the D2D UE checks whether the D2D grant is a data-only grant (620).

If the D2D grant is not a data-only grant, the D2D grant is an SA-only grant, so that SA information is obtained (635), the SA information is stored, and the process moves to step 605 until it matches the data grant to check the PDCCH Can wait (640).

If the D2D grant is a data-only grant, the D2D UE acquires RPT information and combines the SA and RPT based on the previous SA (625), and transmits data from the granted RPT of the next D2D frame and transmits SA There is (645).

31 is a diagram illustrating an operation of a UE when a UE according to the present disclosure receives a D2D grant but there is no transmission data.

When the UE receives the D2D grant from the eNB but there is no data to be transmitted at the time when the SA is to be transmitted, the UE transmitter may perform one of the following alternatives.

The first alternative is that the UE does not transmit the SA message.

The second alternative is to indicate that the UE transmits an SA message and there is no data to be transmitted.

A third alternative is for the UE to transmit the SA message and indicate the allocated data resource index (data RB index, and T-RPT index). In the corresponding data resource, the UE does not transmit data until new data arrives. When data arrives, the UE transmits the data from the next available resource previously set for each MAC PDU. For example, as illustrated in FIG. 31, even if the UE-A 3100 receives 3102 of the D2D grant from the eNB, the UE-A 3100 has no data to transmit at the time point 3104 of transmitting the SA message. . Then, new data arrives to the UE-A 3100 after about 20 ms (3106). In this case, the UE-A 3100 transmits an SA, but does not transmit data until the new data arrives. When the new data arrives, the UE-A 3100 sets a set of four transmission opportunities 3120, 3122, 3124, 3126 in the next resource 3120 for one MAC PDU. ) Transmits one MAC PDU. This method can reduce the transmission delay of the data packet.

On the other hand, in the first alternative and the second alternative, the UE gives up the transmission opportunity in the current transmission period 3110. That is, in the first alternative and the second alternative, when new data is generated within the transmission period 3110, the generated data cannot be transmitted. This is because in the first alternative and the second alternative, the UE has to wait for a new D2D grant to transmit the generated data.

7 is a diagram illustrating a method of obtaining and transmitting SA/RPT information by an out-of-coverage D2D transmitting UE according to the present disclosure with the help of an in-coverage UE.

The D2D UE out of coverage may obtain D2D related information from the in coverage UE (700).

The non-coverage D2D UE synchronizes the D2D frame using the D2D related information (705).

The non-coverage D2D UE decodes the SA and acquires information of the RPT in use (710). As described in Table 4, the “Flag for SPS Indication” field in the SA content may be used to determine the availability of the SA and data RPT. If the value of the “Flag for SPS Indication” field is 1, the SA and RPT will be used in the next D2D frame, so it is considered that the SA and RPT are not available (for other purposes). If the “Flag for SPS Indication” field value is 0, the SA and RPT are considered as available resources.

The D2D UE out of the coverage checks whether there are unused SAs and RPTs (715).

As a result of the check in step 715, if there are no unused SAs and RPTs, the non-coverage D2D UE switches to the sleep mode (720) and may move to step 710 to check the next SA region.

As a result of the check in step 715, if there are unused SAs and RPTs, the out of coverage D2D UE checks whether there is an SA-RPT pair with a predefined implicit mapping rule (725).

As a result of the 725 check, if there is an SA-RPT pair of an implicit mapping rule, the non-coverage D2D UE selects one SA-RPT pair (730). That is, the non-coverage D2D UE may select an SA-RPT pair through implicit signaling.

As a result of the 725 check, if there is no SA-RPT pair of the implicit mapping rule, the non-coverage D2D UE selects one SA and one RPT, respectively (735). That is, the non-coverage D2D UE may select an SA-RPT pair through explicit or semi-permanent signaling.

The non-coverage D2D UE transmits the SA and the RPT in the SA-RPT of the next D2D frame using the selected SA-RPT (740).

8 is a diagram illustrating an operation of a D2D receiving UE according to the present disclosure.

The D2D UE synchronizes the D2D frame using the acquired D2D-related information (800).

The D2D UE checks the SA area and checks whether there is an SA related to it (805).

If there is no related SA as a result of the 805 check, the D2D UE may switch to the sleep mode (820) and move to step 805 to check the next SA region.

If there is a related SA as a result of the 805 check, the D2D UE decodes the related SA to obtain RPT information and transmission parameters (810), and decodes data based on the RPT information in the data area of the D2D frame. Can (815). In step 810, the'Mode Indication' field of the SA content (Table 3 or 4) may be used to distinguish between the mode 1 and the mode 2. In step 815, the UE may decode data with an appropriate operation from a data pool corresponding to the distinct mode 1 or mode 2.

FIG. 27 is an exemplary diagram of a method of operating an in-coverage UE transmitter in mode 1 and mode 2 according to the present disclosure.

The in-coverage UE transmitter acquires SA pool information or data pool information from a system information block (SIB) (received from the eNB) (2700).

The UE transmitter transmits a D2D scheduling request (SR) or a buffer status report (BSR) to the eNB (2702).

The UE transmitter checks whether a D2D grant is received from the eNB under a certain condition (2704).

When reception of the D2D grant is checked in the 2704 check, the UE transmitter may operate in mode 1. In this case, the UE transmitter acquires SA information or data RPT information allocated from the D2D grant (2706). The UE transmitter acquires T-RPT (time domain RPT) bitmap repetition information (2708). The UE transmitter transmits an SA in the following mode 1 SA pool (2710). The UE transmitter transmits data based on the acquired RPT after the mode 1 SA pool (2712). That is, in mode 1, the UE transmitter can transmit data immediately after the mode 1 SA pool.

If the reception of the D2D grant is not checked in the 2704 check (eg, for a certain period), the UE transmitter may abandon the reception of the D2D grant from the base station and fall back to mode 2 (2714). . In this case, the UE transmitter decodes the SA from the mode 2 SA pool (2716). The UE transmitter selects one SA and selects a data RPT for data transmission (2718). The UE transmitter transmits an SA in the mode 2 SA pool (2720). The UE transmitter may transmit data based on the RPT in the mode 2 data pool (2722).

28 is an exemplary diagram of a method in which an in-coverage UE receiver operates in different modes of an SA pool or a data pool according to the present disclosure.

The in-coverage UE receiver acquires SA pool information or data pool information from the SIB (2800).

The UE receiver synchronizes each SA pool to receive data (2802).

The UE receiver determines whether the SA pool to be used is a mode 1 SA pool, a mode 2 SA pool, or a common SA pool for mode 1 and mode 2 using the obtained SA pool information. Specifically, for example, the UE receiver checks whether the SA pool to be used is a mode 1 SA pool (2804), checks whether it is a mode 2 SA pool (2806), and checks whether it is a common SA pool for mode 1 and mode 2 (2808). ) At least one of the operations may be performed in order. However, the order of execution may be arbitrarily changed.

When it is determined that the SA pool mode 1 SA pool to be used in the 2804 check, the UE receiver decodes the SA and acquires an interested SA resource or a data RPT resource (2810). In this case, the UE receiver may acquire T-RPT bitmap repetition information (2812). The UE receiver may receive data based on the RPT after the mode 1 SA pool (2814).

If it is determined that the SA pool mode 2 SA to be used in the 2806 check, the UE receiver decodes the SA and acquires an interested SA resource or a data RPT resource (2820). In this case, the UE receiver may receive data based on the RPT from the mode 2 data pool (2822).

When it is determined that the SA resolution mode 1 and mode 2 common SA pools to be used in the 2808 check, the UE receiver decodes the SA and acquires an interested SA resource or a data RPT resource (2830). In this case, the UE receiver may identify whether the decoded SA is mode 1 or mode 2 (2832). The UE receiver checks whether the decoded SA is a mode 1 SA (2834). If the result of the 2834 check is mode 1, the UE receiver receives data based on the RPT after the SA pool (2836). If the result of the 2834 check is not mode 1, the UE receiver determines that it is mode 2 (2838), and receives data based on the RPT from the mode 2 data pool (2840).

FIG. 29 is a diagram illustrating a procedure of an operation in which a UE transmitter in coverage obtains T-RPT bitmap repetition information when the number of transmission MAC PDUs is set by SIB for mode 1 in the present disclosure.

The procedure of FIG. 29 may be a detailed procedure of operation 2708 of FIG. 27.

The in-coverage UE transmitter acquires the number M of transmission MAC PDUs from the SIB (2900).

The UE transmitter acquires a T-RPT bitmap (N,k) from the D2D grant (2902).

The UE transmitter derives the number of repetitions of the T-RPT bitmap using the equation “R=4M/k” (2904).

The UE transmitter transmits data from a resource using the derived information (2906).

FIG. 30 is a diagram illustrating a procedure of an operation in which a UE receiver in coverage obtains T-RPT bitmap repetition information when the number of transmission MAC PDUs is set by SIB for mode 1 in the present disclosure.

The procedure of FIG. 30 may be a detailed procedure of operation 2812 of FIG. 28.

The in-coverage UE receiver acquires the number M of transmission MAC PDUs from the SIB (3000).

The UE receiver obtains a T-RPT bitmap (N,k) from the SA (3002).

The UE receiver derives the number of repetitions of the T-RPT bitmap using the equation “R=4M/k” (3004).

The UE receiver receives data from a resource using the derived information (3006).

9 illustrates an example of resource allocation for solving a half-duplex problem according to an embodiment of the present disclosure.

Due to the inherent characteristics of D2D communication, additional information may be considered as a reference for D2D communication scheduling. For example, when UEs (UE1 and UE2) belonging to the same group in which there is a need for reception and transmission between each other are scheduled in the same D2D frame, the base station has different SA/ Resource patterns can be assigned. Specifically, UE1 may use the subregion 910 as a transmission region and UE2 may determine a resource pattern to use the subregion 910 as a reception region. In addition, the UE1 may determine a resource pattern to use the sub-region 920 as a reception region and the UE2 to use the sub-region 920 as a transmission region.

UE1 and UE2 can receive signals from each other by using such a scheduled resource pattern, and thus, a problem due to half-duplex (half-duplex) can be solved.

In particular, in the case of an out-of-coverage UE, the transmitting UE may prefer to select a resource pattern selected by another UE in the same group and a resource pattern that does not overlap in the time domain.

14 is an exemplary diagram of SA patterns for avoiding the half-duplex restriction of the present disclosure.

For example, each SA may be repeated several times by a preset pattern. As shown in FIG. 14, UE1 uses SA1 (1400, 1402), and UE2 uses SA3 (1410, 1412). In the first time unit, UE1 and UE2 transmit SAs 1400 and 1410, respectively, so they cannot hear each other. However, UE1 and UE2 can listen to each other's second SAs 1402 and 1412 because the second SAs 1402 and 1412 are not transmitted at the same time. That is, the second SAs 1402 and 1412 are transmitted in different time units. This is useful when UE1 and UE2 are in the same group and need to listen to each other.

Several additional options of the SA pattern are described. It is assumed that the SA resource pool has Nt subframes in the time domain and Nf resource blocks in the frequency domain. Each SA occupies one subframe (SF) in the time domain and one resource block (RB) in the frequency domain.

The resource index of the second SA may be derived from the resource index of the first SA. For example, the time index of the second SA may be derived from the time index of the first SA having an arbitrary offset, and the frequency index of the second SA is the first having an arbitrary offset or a frequency hopping pattern. It can be derived from the frequency index of the SA. Alternatively, the time and frequency index of the second SA may be derived from a function of both the time and frequency index of the first SA.

Based on the above method, connection of two SAs used by one UE may have several options.

The connection of two SAs used by one UE is illustrated in FIGS. 25A to 25D.

In option 1 of FIG. 25A, two SAs used by the same UE are always contiguous in the time domain. The first SA transmission is always in a subframe of an even index (eg, 0, 2, 4, ...), and the second SA transmission (repetition of the first SA transmission) is always in the next subframe (eg , The index is at 1, 3, 5, …). As an example, the connection of the 0th SA (initial transmission) and the 1st SA (repetition) of the UE is the connection of the resource block A (2500) of the 0th subframe and the resource block A'(2502) of the 1st subframe, respectively. Can be The frequency hopping rule may be further considered in determining the connection between the two SAs. The previously described data frequency hopping rules (Type 1 and Type 2) may also be used for SA frequency hopping.

In option 2 of FIG. 25B, two SAs used by the same UE are not contiguous in the time domain. Accordingly, option 2 may have additional time diversity compared to option 1. The second SA has a time domain offset from the first SA used by the same UE. As an example, the connection of the 0th SA (initial transmission) and the 1st SA (repetition) of the same UE is a resource block A 2510 of a 0th subframe and a resource block A'2512 of a 4th subframe, respectively. It can be a connection of. In this case, the time domain offset is 4.

In option 3 of FIG. 25C, the first SA is always in the first half subframes of the time domain, and the second SA is in the second half subframes of the time domain. There may be a predetermined connection rule for two SAs used by the same UE. As an example, the connection of the 0th SA (initial transmission) and the 1st SA (repetition) of the same UE is a resource block A 2520 of a 0th subframe and a resource block A'2522 of a 4th subframe, respectively. It can be a connection of.

In option 4 of FIG. 25D, a resource to which the first SA can be transmitted occupies half of the total resources, and the half of the resources may have a triangular shape. In addition, the second SA occupies the other half of the triangular shape resources. There may be a predetermined connection rule for two SAs used by the same UE. As an example, the connection of the 0th SA (initial transmission) and the 1st SA (repetition) of the same UE is a resource block A 2530 of a 0th subframe and a resource block A'2532 of the 1st subframe, respectively. It can be a connection of.

The mathematical expression of the options of the SA pattern is described. It is assumed that the first SA has an index of (nt0, nf0). Here, nt0 represents a subframe (SF) in the time domain, and nf0 represents a resource block (RB) in the frequency domain.

In the options 1 and 2, the indexes (nt1, nf1) of the second SA may be defined as follows.

Here, a, b, c, and d are predefined parameters and are cell-specific. Nt is the number of subframes in the time domain in the SA resource pool, and Nf is the number of resource blocks in the frequency domain in the SA resource pool.

In option 3, the indexes (nt1, nf1) of the second SA may be defined as follows.

Here, a, b, c are predefined parameters and are cell-specific.

In option 4, the indexes (nt1, nf1) of the second SA may be defined as follows.

Here, a, b, c, d are predefined parameters and are cell-specific.

Next, design of resources for D2D discovery will be described with reference to FIGS. 15 to 17.

In each discovery period, D2D UEs may transmit discovery messages in one or more DRUs. When multiple DRUs are used by one UE, repetitive transmission of discovery messages is useful for increasing discovery coverage, especially for UEs with low power transmission when power control technology is applied. The number of DRUs used for repeated transmissions may be preset by the network according to the size of the network, the density of the UE, the transmission environment, and the like. Given the number of DRUs (eg, K) for repeated transmissions, indexes of DRUs used in the same UE may be predefined or derived by a deterministic linkage rule.

DRUs for the same UE may be referred to as a DRU pair or a connected DRU pair. When the UE transmits a discovery message in DRUs of a certain discovery period, indexes of DRUs used for transmission of the next discovery period may be derived by a resource hopping rule. The resource hopping rule may include a DRU hopping pattern and a DRU pair hopping pattern.

Given the index of the URU to be used by the UE in any discovery period, the DRU hopping pattern defines a hopping rule that derives the index of the DRU to be used by the UE in the next discovery period. If the UE uses DRUs belonging to the same predefined DRU pair in any discovery period, DRUs used by the UE in the next discovery period may not be in the same predefined DRU pair. In this case, DRUs used by the UE and not in the same predefined DRU pair may be referred to as virtual DRU pairs.

The DRU pair hopping pattern defines a hopping rule for inducing an index of a DRU pair used by the UE in the next discovery period. That is, DRUs belonging to the same predefined DRU pair will be used by the same UE. The frequency hopping rule may use only DRU hopping, only DRU pair hopping, or a combination of DRU hopping and DRU pair hopping. For example, the DRU pair hopping interval M (1≦M≦∞) may be defined by indicating how DRU hopping and DRU pair hopping are combined. That is, DRU pair hopping may be used once for M discovery periods, and DRU hopping may be used within each discovery period constituting the M discovery periods. If M=1, only DRU pair hopping will be used, and if M=∞, only DRU hopping will be used. In other cases, DRU hopping and DRU pair hopping are used together. The value of M may be set in advance and may be signaled by the network.

15A and 15B are diagrams illustrating a D2D discovery resource hopping method according to the present disclosure.

In the drawings of FIGS. 15A and 15B, a square marked with A (e.g., 1500) is a DRU used to transmit a discovery message by UE-A, and a square marked with A'(e.g., 1502) is a UE- It is a DRU used by A to transmit the repetition of the discovery message. The solid line (e.g., 1510) between the square 1500 marked A and the square 1502 marked A'is a line of a preset DRU pair (e.g., 1520) used by the same UE-A. ), and a dotted line between the square marked with A and the square marked with A'(for example, 1512) is a line of the virtual DRU pair 1522 used by the same UE.

Referring to FIG. 15A, one discovery period may consist of 48 DRUs (Nt=6, Nf=8). Each DRU may be represented by a joint index in the time and frequency domain, for example, <nt, nf> (0≤nt≤5, 0≤nf≤7). The number of DRUs in the DRU pair is 2, which means that two transmissions (K=2) are considered for one UE to transmit a discovery message. Thus, there may be 24 DRU pairs.

At discovery time 0 (Dt=0), UE-A, UE-B, and UE-C transmit discovery messages in DRU pair 0 (1520), DRU pair 1, and DRU pair 2, respectively. DRU pair 0 (1520) includes two consecutive DRUs and may be, for example, DRU<nt=0,nf=7> (1500) and DRU<nt=1,nf=7> (1502). At the next discovery time 1 (Dt=1), the DRUs to be used are changed based on the DRU hopping rule. For example, UE-A uses DRU<nt=0,nf=7> and DRU<nt=2,nf=6>, but the used DRUs no longer belong to a predefined DRU pair, so the virtual DRU It is denoted as pair 0 (1522). At discovery time M-1 (Dt=M-1), the DRUs used are also different, but the virtual DRU pair is always connected. For example, UE-A always uses virtual DRU pair 0.

Referring to FIG. 15B, DRU pair hopping is used at discovery time M (Dt=M). For example, UE-A is hopped to use predetermined DRU pair 1 1530. The DRU pair to be used by other UEs is also changed. By doing so, resource hopping continues based on the DRU hopping and DRU pair hopping rules.

16 is a diagram illustrating a D2D discovery resource hopping method when only DRU pair hopping is applied in the present disclosure.

When M=1, only DRU pair hopping is used, which is illustrated in FIG. 16.

The discovery cycle D_cycle is, for example, the number of radio frames, and may be set as D_cycle = 1024, 512, 256, 128, and may be broadcast in system information. Accordingly, the time index dt of the discovery period may be calculated as dt = SFN/D_cycle using a system frame number (SFN).

As illustrated in FIG. 16, from a system design point of view, if the number of transmissions per UE (that is, the number of DRUs in one pair) within a single discovery period is greater than 1, only DRU pair hopping is a default configuration. It can be set as, and the number of repeated transmissions (K) can be signaled as system information. This default setting is simpler and requires less signaling overhead since it only requires signaling of the number of repeated transmissions (K) as system information.

If only one DRU is transmitted per UE, the hopping pattern can be generalized as follows.

17 is a diagram illustrating a periodic shuffling method for solving a hidden UE problem of the present disclosure.

As shown in FIG. 17, periodic shuffling 1710 is used with arbitrary hopping 1700, 1720 patterns.

The periodic shuffling 1710 may periodically randomize the DRU arrangement to improve discovery performance. The shuffling period may be determined based on a discovery size and a hopping function. In some scenarios, shuffling allows two hidden UEs (or DRUs) to quickly hear each other. This also makes it possible to avoid persistent hopping patterns.

Next, a connection pattern design of a DRU pair will be described with reference to FIGS. 18 to 20.

There may be a predefined DRU connection pattern. The DRU connection pattern is related to the number of discovery message transmissions and the size of the discovery resource pool.

Given the number of discovery message transmissions, the DRU connection pattern can be designed in various ways. For example, in FIG. 12, one DRU pair always consists of two consecutive DRUs.

A common DRU pair connection pattern can be used by different cells. Also, different cells may have different connection patterns.

18 is an exemplary diagram of a cell-specific DRU connection pattern when K=2 according to the present disclosure.

In FIG. 18, a case where K=2 and different cells have different DRU connection patterns is illustrated. In this example, DRUs of one DRU pair always have the same frequency index, but different time indexes (contiguous or non-contiguous DRUs). The design of FIG. 18 is simple, but UEs using DRU pairs located in the same TTIs do not hear each other. Specifically, for example, since UE-A uses a DRU pair 1800, the UE-A uses DRU pairs 1802, 1804, 1806, 1808 located in the same TTI as the DRU pair 1800 You cannot hear the UEs, that is, UE-B, UE-C, UE-D, UE-E and UE-F.

Accordingly, the DRU connection pattern may be more flexibly designed to connect DRUs having different time indexes and different frequency indexes, as illustrated in the different connection patterns 1820 and 1830 of FIG. 18.

Given the number of subframes in the discovery period and the number of DRUs used for a single UE, another efficient design is to combine all possible cases of K DRUs with different time indices.

19 is another exemplary diagram of a cell-specific DRU connection pattern when K=2 according to the present disclosure.

개의 가능한 연결 페어들은 (nt=0 및 nt=1)(1900), (nt=0 및 nt=2)(1902), (nt=0 및 nt=3)(1904), (nt=1 및 nt=2)(1906), (nt=1 및 nt=3)(1908) 및 (nt=2 및 nt=3)(1910) 이다.As illustrated in FIG. 19, a combination when Nt=4 and K=2, that is,

(Nt=0 and nt=1)(1900), (nt=0 and nt=2)(1902), (nt=0 and nt=3)(1904), (nt=1 and nt =2)(1906), (nt=1 and nt=3)(1908) and (nt=2 and nt=3)(1910).

As illustrated in the different connection patterns 1920 and 1930 of FIG. 19, different connection patterns may be used for different cells by using different frequency indexes of DRUs in the same pair. In this case, each of the six UEs can detect at least one DRU from another UE, and the half-duplex problem can be partially alleviated. Specifically, for UE-1A using the (1A, 1A') DRU pair, only UE-2A using the (2A, 2A') DRU pair becomes a hidden UE. That is, UE-1A cannot hear only discovery transmissions from UE-2A, and can hear discovery transmissions from other UEs.

20 is a diagram illustrating a DRU pair connection pattern applied to SA transmission according to the present disclosure.

As illustrated in FIG. 20, the connection pattern may be applied to an SA transmission pattern to avoid a half-duplex problem. In particular, the pattern can be applied to each of a group of different UEs, thereby allowing UEs belonging to the same group to hear each other's discovery. The pattern design may be affected by the number of subframes for SA transmission.

Similarly, the SA connection pattern illustrated in FIG. 25 may also be applied to the DRU pair connection pattern, which is illustrated in FIG. 26.

26A to 26C are exemplary diagrams of DRU connection patterns when K=3 according to the present disclosure.

26A to 26C illustrate a DRU connection pattern corresponding to the SA connection pattern of FIG. 25. Given a DRU pair, it is assumed that the initial DRU transmission has an index (nt_0,nf_0). Here, nt_0 represents a DRU index in the time domain, and nf_0 represents a DRU index in the frequency domain. The k-th repeated DRU transmission of the same DRU pair is derived from the index of the initial DRU transmission.

In option 1 of FIG. 26A, DRUs by the same UE are always contiguous in the time domain. As an example, the connection of the 0th DRU, 1st DRU, and 2nd DRU of the UE is resource block A (2600) of the 0th subframe, resource block A'(2602) of the 1st subframe, and the 2nd subframe. It may be a connection of the resource block A'' (2604).

In this case, the time and frequency indexes (nt_k, nf_k) of the k-th DRU may be defined as follows.

Here, a, b, c are predefined parameters and are cell-specific.

In option 2 of FIG. 26B, the 0th DRU transmission by the same UE uses the resources in the 0th transmission interval 2610, the 1st DRU transmission uses the resources in the 1st transmission interval 2612, and the 2nd DRU Transmission uses resources in the second transmission interval 2614. As an example, the connection of the 0th DRU, 1st DRU, and 2nd DRU of the UE is resource block A (2620) of the 0th subframe, resource block A'(2622) of the 2nd subframe, and the 4th subframe. It may be a connection of the resource block A'' (2624).

In this case, the indexes (nt_k, nf_k) of the k-th DRU may be defined as follows.

Here, a, b, c, d are predefined parameters and are cell-specific.

In Option 3 of FIG. 26C, the 0th DRU transmission by the same UE uses the resources in the 0th transmission interval 2630, the 1st DRU transmission uses the resources in the 1st transmission interval 2632, and the 2nd DRU Transmission uses the resources in the second transmission period 2632. As an example, the connection of the 0th DRU, the 1st DRU and the 2nd DRU of the UE is resource block B 2640 of the 0th subframe, resource block B'2642 of the 3rd subframe, and the 5th subframe, respectively. It may be a connection of resource block B'' (2644) of.

In this case, the indexes (nt_k, nf_k) of the k-th DRU may be derived from the indexes (nt_k1, nf_k1) of the (k-1)-th DRU as follows.

Here, a, b, c are predefined parameters and are cell-specific.

Next, the design of the hopping pattern will be described with reference to FIG. 21.

Since several hidden UEs may exist in a specific UE within the same discovery period, a hopping pattern for solving the half-duplex problem may be used.

First, the DRU hopping pattern will be described.

Assuming that the UE transmits the discovery message in the DRU <nt, nf> of a discovery period, the DRU hopping pattern is a rule for inducing the DRU to be used by the UE in the next discovery period, that is, DRU <nt_next,nf_next>. define. Any hopping pattern can be used to solve the half-duplex problem. DRU hopping attempts to solve the half-duplex problem at the DRU level. That is, DRU hopping enables detection of at least one DRU of a previously hidden UE (in a previous discovery period) in each discovery period.

Second, the connected DRU Peher Hopping pattern will be described.

Unlike the DRU hopping pattern, the DRU pair hopping pattern aims to solve the half-duplex problem at the DRU pair level. When the UE transmits a discovery message in the DRU pair p of any discovery period, the DRU pair hopping pattern defines a rule for inducing the DRU pair p_next to be used by the UE in the next discovery period. DRUs in the predefined DRU pair p_next may be used for discovery message transmission.

21 is an exemplary diagram of D2D discovery resource hopping to which a hopping pattern is applied in the present disclosure.

The DRU hopping rule is a block interleaving style, and may be, for example, a method of reading from a column 2100 and writing it as a row 2102. The DRU pair hopping rule may also be a block interleaving style, but read and write can be performed in pairs. For example, the A-A' pair 2110 and the B-B' pair 2112 can be read and written together with the A-A' pair 2120 and B-B' pair 2122.

The case a) of FIG. 21 indicates that DRU hopping and DRU pair hopping can be used together when M=3, and case b) indicates that only DRU pair hopping is used when M=1.

The case b) of FIG. 21 (ie, M=1 and only DRU pair hopping is used) may be set as a default setting. Accordingly, hopping may be applied to the first DRU transmission, and (K-1) DRUs of the same DRU pair may be obtained by the DRU connection rule. The hopping pattern for the first DRU transmission may be described as follows.

Here, nt denotes a logical time index of the first transmission within one discovery period, and nf denotes a logical frequency index of the first transmission within one discovery period. Here, a, b, c are predefined parameters and are cell-specific.

It is also possible to use time hopping or frequency hopping. A hopping case may be signaled through an upper layer. For example, two bits can be used to indicate a hopping case. For example, '00' denotes frequency and time hopping, '01' denotes only time hopping, '10' denotes only frequency hopping, and '11' denotes no hopping.

If resource allocation and resource hopping are not controlled by the base station (ie, if the UE selects and accesses a DRU by itself), only DRU pair hopping may be used. The UE may select a DRU pair to be accessed in one discovery period, and may select another DRU pair in the next discovery period. The following options can be used in DRU selection.

In option 1, the UE selects a first DRU having the same probability from all the first DRUs, and other DRUs in the same DRU pair are derived from the DRU connection pattern. This is equivalent to selecting a DRU pair with the same probability from all DRU pairs.

In option 2, the UE selects a first DRU with the same probability from the first DRUs of a lower power level (e.g., power less than X dBm), and other DRUs in the same DRU pair are derived from the DRU connection pattern. do.

In option 3, the UE selects the first DRU with the lowest power level, and other DRUs in the same DRU pair are derived from the DRU connection pattern.

In option 4, the UE selects a DRU pair with the same probability from DRUs with a lower power level (ie, the average power of DRUs belonging to the same DRU pair is less than X dBm).

In option 5, the UE selects the DRU pair with the lowest power level.

Next, a discovery method of the UE will be described with reference to FIGS. 22 to 24.

In inter-cell discovery, if a cell specific discovery pattern is required, different methods can be designed by applying the proposed method. In order to make the discovery pattern cell specific, parameters such as, for example, a DRU connection pattern, a DRU hopping pattern, a DRU pair hopping pattern, and a DRU pair hopping interval may be used. Thus, there may be many possible approaches for designing cell specific hopping patterns. For example, the DRU connection pattern and the DRU hopping pattern may be common for each cell, but the DRU pair hopping pattern may be cell-specific and the DRU pair hopping interval may be cell-specific. Depending on the system requirements, different hopping patterns can be designed.

22 illustrates a procedure for a UE of the present disclosure to transmit an initial diskbury message by receiving resource allocation from a base station.

The terminal acquires discovery resource pool information and related discovery parameters from the system information (2200). As an example of the parameter, the terminal may acquire at least one of information about a DRU pair connection pattern, a number of transmissions (K), and a DRU pair hopping interval (M).

The terminal acquires resource information allocated by the base station (2202). As an example of resource information, the terminal may obtain a DRU pair index (p).

The terminal synchronizes in the next discovery period (2204). As an example, the terminal can synchronize with the index dt.

The terminal checks whether the remainder of dividing dt by M is 0 (2206).

If the remainder of the 2206 check is 0, the UE transmits a discovery message from DRUs of the p-th predefined DRU pair and may receive a discovery message from other DRU pairs of different TTIs (2208).

If the remainder of the 2206 check is not 0, the UE induces a virtual connection of each DRU pair in the current discovery period according to the DRU hopping rule (2210). In addition, the UE transmits a discovery message from DRUs of a p-th virtual DRU pair and receives a discovery message from other virtual DRU pairs of different TTIs (2212).

The UE combines DRUs belonging to the same DRU pair and decodes the discovery message (2214).

The terminal updates the information of the discovered UEs (2216).

Until discovery transmission is terminated, the terminal transmits a discovery message in the next discovery periods based on the resource hopping rule (2218 ).

23 illustrates a discovery resource access procedure when the UE of the present disclosure transmits a discovery message in a next discovery period.

The UE transmits a discovery message in DRUs of the p-th DRU pair (or virtual DRU pair) in the discovery period dt (2300).

The terminal synchronizes in the next discovery period and increases the value of dt by 1 (2302).

The terminal checks whether the remainder of dividing dt by M is 0 (2304).

If the remainder, which is a result of the check 2304, is 0, the terminal updates the index p of the DRU pair to be used for transmission of the discovery message in the current discovery period according to the DRU pair hopping rule (2306). In addition, the UE transmits a discovery message from DRUs of a p-th predefined DRU pair, and may receive a discovery message from another DRU pair of other TTIs (2308).

If the remainder, which is a result of the check 2304, is not 0, the UE induces a virtual connection of each DRU pair in the current discovery period according to the DRU hopping rule (2310). In addition, the UE transmits a discovery message from DRUs of the p-th virtual DRU pair, and may receive a discovery message from other virtual DRU pairs of different TTIs (2312).

The UE may combine DRUs belonging to the same DRU pair and decode the discovery message (2314).

The terminal updates the information of the discovered UEs (2316).

The terminal checks whether discovery is terminated by the base station (2318).

As a result of the check 2318, when discovery is terminated by the base station, the terminal stops transmitting the discovery message from the next discovery period (2320).

As a result of the check 2318, if discovery is not terminated by the base station, the terminal may perform a discovery operation for the next discovery time (dt = dt +1) from step 2302.

24 illustrates a procedure for receiving a discovery message by a UE of the present disclosure.

The terminal acquires discovery resource pool information and related discovery parameters from the system information (2400). As an example of a parameter, the terminal may acquire at least one of information about a DRU connection pattern, a number of transmissions (K), and a DRU pair hopping interval (M).

The terminal may synchronize in the next discovery period (2402).

The terminal checks whether the remainder of dividing dt by M is 0 (2404).

If the remainder, which is a result of the check 2404, is 0, the terminal receives a discovery message of each predetermined DRU pair (2406).

If the remainder, which is a result of the check 2404, is not 0, the terminal induces a virtual connection of each DRU pair in the current discovery period according to the DRU hopping rule (2408), and receives a discovery message of each virtual DRU pair. Can do it (2410).

The UE may combine DRUs belonging to the same DRU pair and decode the discovery message (2412).

The terminal updates the information of the discovered UEs (2414), and may perform operations from step 2402 for the next discovery period operation.

10 is a diagram illustrating a configuration of a D2D UE device of the present disclosure.

The D2D UE apparatus 1000 may include a transmission/reception unit 1010 capable of communicating signals with a communication base station or other D2D UEs, and a control unit 1420 that controls the transmission/reception unit 1010. It goes without saying that the transmission/reception unit 1010 and the control unit 1020 may be implemented as a single device.

The control unit 1020 is a configuration unit that implements the acquisition and signal transmission of the resource allocation information of the D2D UE described in the present disclosure. That is, it may be understood that all operations of the UE described above through FIGS. 3 to 30 of the present disclosure are performed by the controller 1420.

An example of resource allocation illustrated in FIGS. 3 to 30, a signaling procedure between a base station and a UE, an example of a method of obtaining and transmitting information of a UE, an example of a device configuration, an example of an SA connection pattern, an example of a DRU connection pattern It should be noted that, the in-coverage UE transmitter/receiver operation example is not intended to limit the scope of the present disclosure. That is, all the procedures, signaling, components, or steps of operation described in FIGS. 3 to 30 should not be interpreted as being essential components for the implementation of the invention, and including only some components does not impair the essence of the invention. It can be implemented within a range that does not.

The above-described operations can be realized by providing a memory device storing a corresponding program code in a base station of a communication system or an arbitrary component in a terminal device. That is, the control unit of the base station or the terminal device may execute the above-described operations by reading and executing the program code stored in the memory device by the processor or CPU (Central Processing Unit).

The entities, functions, base stations, load managers, various components of a terminal device, and modules described in this specification are hardware circuits, for example, a complementary metal oxide semiconductor. It may be operated using a hardware circuit such as a base logic circuit, firmware, software, and/or a combination of hardware and firmware and/or software embedded in a machine-readable medium. As an example, various electrical structures and methods may be implemented using transistors, logic gates, and electrical circuits such as application-specific semiconductors.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications may be made without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure is limited to the described embodiments and should not be defined, and should be determined by the scope of the claims and equivalents as well as the scope of the claims to be described later.

Claims (16)

In the terminal method for performing D2D communication in a wireless communication system,
Transmitting a first discovery message using a first resource; And
Including an operation of transmitting at least one repetitive discovery message corresponding to the first discovery message by using at least one second resource,
The at least one second resource for the at least one repetitive discovery message is determined based on at least one of a time index and a frequency index of the first resource for the first discovery message Become,
The frequency index of the at least one second resource is a result of multiplying the number of transmissions of the at least one repetitive discovery message and a predetermined value, and a modulo Nf operation for the sum of the frequency index of the first resource ( modulo Nf operation),
Wherein Nf represents the total number of frequency indices in a resource pool for the D2D communication.
The method of claim 1,
Each of the first resource and the at least one second resource includes two adjacent resource blocks (RBs) in a frequency domain.
delete The method of claim 1,
The frequency index of the at least one second resource is increased or decreased by a multiple of a predetermined value from the frequency index of the first resource.
delete The method of claim 1,
The frequency index of the at least one second resource for the k-th transmission of the at least one repetitive discovery message is determined by <Equation 14>,
<Equation 14>

In Equation 14, nf_k represents the frequency index of the k-th transmission, k represents the number of times of transmission of the at least one repetitive discovery message, a, b, and c are each predetermined value, and nf_0 is And Nf denotes the total number of frequency indices in a resource pool for the D2D communication.
The method of claim 1,
The method, characterized in that the information on the resource pool for the D2D communication is received through a system information block (SIB).

The method of claim 1,
Wherein the first resource for the first discovery message and the second resource for the at least one repetitive discovery message are adjacent in a time domain.

In a terminal device for performing D2D communication in a wireless communication system,
A transmission/reception unit; And
The first discovery message is transmitted using a first resource, and at least one repetitive discovery message corresponding to the first discovery message is transmitted using at least one second resource. Including a control unit for controlling the transmission and reception unit,
The at least one second resource for the at least one repetitive discovery message is determined based on at least one of a time index and a frequency index of the first resource for the first discovery message Become,
The frequency index of the at least one second resource is a result of multiplying the number of transmissions of the at least one repetitive discovery message and a predetermined value, and a modulo Nf operation for the sum of the frequency index of the first resource ( modulo Nf operation),
Wherein Nf represents the total number of frequency indices in a resource pool for the D2D communication.
The method of claim 9,
Wherein each of the first resource and the at least one second resource includes two adjacent resource blocks (RBs) in a frequency domain.

delete The method of claim 9,
And the frequency index of the at least one second resource is increased or decreased by a multiple of a predetermined value from the frequency index of the first resource.
delete The method of claim 9,
The frequency index of the at least one second resource for the k-th transmission of the at least one repetitive discovery message is determined by <Equation 14>,
<Equation 14>

In Equation 14, nf_k represents the frequency index of the k-th transmission, k represents the number of times of transmission of the at least one repetitive discovery message, a, b, and c are each predetermined value, and nf_0 is And Nf denotes the total number of frequency indices in a resource pool for the D2D communication.
The method of claim 9,
The device, characterized in that the information on the resource pool for the D2D communication is received through a system information block (SIB).
The method of claim 9,
The apparatus according to claim 1, wherein the first resource for the first discovery message and the second resource for the at least one repetitive discovery message are adjacent in a time domain.

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