WO2015062073A1

WO2015062073A1 - Method and apparatus for device-to-device communication

Info

Publication number: WO2015062073A1
Application number: PCT/CN2013/086422
Authority: WO
Inventors: 刘勇; 徐艳丽; 李栋
Original assignee: 上海贝尔股份有限公司
Priority date: 2013-11-01
Filing date: 2013-11-01
Publication date: 2015-05-07
Also published as: CN105637958A; CN105637958B

Abstract

Provided are a method and an apparatus for D2D communication. The method comprises: determining broadcast data channel use information comprised a frame structure of D2D broadcast communication; and selecting, according to the determined use information, an idle broadcast data channel from the frame structure to transmit D2D broadcast data.

Description

Method and apparatus for device-to-device communication

The present invention relates to the field of communications, and more particularly to a method and apparatus for device-to-device communication in a communication system. Background technique

The communication mechanism of Device-to-Device (D2D) is an enhancement to a cellular communication system such as Long Term Evolution. In D2D communication, user equipments (UEs) adjacent to each other can communicate directly at a higher data rate. D2D communication can achieve many benefits, such as mitigating the workload of a base station (BS). Currently, the 3rd Generation Partnership Project (3GPP) has already carried out related standardization work on D2D communication.

In D2D communication, a current research hotspot is to cover D2D broadcast communication in the out-of-coverage scenario. A key issue for such D2D broadcast communications is how to effectively support VoIP services. However, the respective coverage areas of a plurality of user equipments for broadcasting may overlap, and if a plurality of user equipments perform D2D broadcast communication at the same time, there is a high possibility of mutual influence.

In the prior art, a random scheduling scheme is employed in D2D broadcast communication. In this random scheduling scheme, each broadcast user equipment randomly selects time resources and frequency resources for transmission of D2D broadcast data. Since time resources and frequency resources are randomly selected, multiple user equipments may use the same or adjacent resources, which may result in uncontrollable collisions and interference.

Based on the above discussion, there is a need in the art for a more efficient solution for supporting D2D broadcast communications in communication systems. Summary of the invention

In order to overcome the above problems in the prior art, the present invention proposes a method and apparatus for D2D communication. According to a first aspect of the invention, a method for D2D communication is provided. The method includes: determining usage information of a broadcast data channel included in a frame structure for D2D broadcast communication; and selecting an idle broadcast data channel from the frame structure to transmit D2D broadcast data according to the determined usage information.

According to a second aspect of the present invention, an apparatus for D2D communication is provided. The apparatus includes: a determining unit configured to determine usage information of a broadcast data channel included in a frame structure for D2D broadcast communication; and a selecting unit configured to select one from a frame structure according to the determined usage information An idle broadcast data channel is used to transmit D2D broadcast data.

According to an embodiment of the present invention, a frame structure for D2D broadcast communication is designed, based on which the scheduling of a broadcasted user equipment is implemented, and synchronization signal transmission is completed in D2D broadcast communication. The solution of the present invention can effectively reduce the probability of collision occurrence and the amount of interference in D2D broadcast communication, and significantly improve the performance of D2D broadcasting.

Other features and advantages of the present invention will be apparent from the description of the preferred embodiments of the invention. DRAWINGS

Other objects and effects of the present invention will become more apparent and easier to understand from the following description of the appended claims.

1 is a flow chart of a method 100 for D2D broadcast communication in accordance with an embodiment of the present invention;

2 is a flow diagram of a method 200 for D2D broadcast communication in accordance with one embodiment of the present invention;

3 is a block diagram of an apparatus 300 for D2D broadcast communication, in accordance with one embodiment of the present invention;

4 is a schematic diagram 400 of a frame structure for D2D broadcast communication, in accordance with one embodiment of the present invention;

Figure 5 is a schematic diagram 500 of muting a broadcast data channel to be retransmitted, in accordance with one embodiment of the present invention; Figure 6 is a schematic diagram 600 of transmitting a synchronization signal in D2D broadcast communication, in accordance with one embodiment of the present invention;

Figure 7 is a schematic diagram 700 of transmitting a synchronization signal in a synchronization signal region in D2D broadcast communication, in accordance with one embodiment of the present invention;

Figure 8 is a diagram 800 of transmitting a synchronization signal in a synchronization signaling area in D2D broadcast communication, in accordance with another embodiment of the present invention.

In all of the above figures, the same reference numerals indicate the same or similar features or functions. detailed description

The embodiments of the present invention are explained and explained in more detail below with reference to the accompanying drawings. The drawings and the embodiments of the present invention are to be considered as illustrative only and not limiting the scope of the invention.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality and operation of possible implementations of systems, methods and apparatus in accordance with various embodiments of the present invention. In this regard, each block of the flowchart or block diagram can represent a module, a program segment, or a portion of code, the module, the program segment, or a portion of code comprising one or more logic for implementing the specified Functional executable instructions. It should also be noted that in some alternative implementations, the functions noted in the blocks may also occur in a different order than that illustrated in the drawings. For example, two successively represented blocks may in fact be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending upon the functionality involved. It is also noted that each block of the block diagrams and/or flowcharts, and combinations of blocks in the block diagrams and/or flowcharts, can be implemented in a dedicated hardware-based system that performs the specified functions or operations. , or can be implemented by a combination of dedicated hardware and computer instructions. The drawings and the embodiments of the present invention are to be considered as illustrative only and not limiting the scope of the invention. The invention is explained and illustrated in more detail below with reference to the accompanying drawings.

In the present invention, a User Equipment (UE) may be various types of terminals such as a mobile phone, a personal digital assistant (PDA), a portable computer, or any other suitable terminal having mobile communication capabilities. The base station can be, for example, a Node B, an eNodeB (eNB), access Point (AP), Wireless Access Station (RAS), and so on.

It should be noted that although the embodiments of the present invention are mainly described using a Long Term Evolution (LTE) system as an example, this is merely exemplary, and the technical solution of the present invention is fully applicable to other suitable systems.

Before describing an embodiment in accordance with the present invention, a frame structure for D2D broadcast communication according to an embodiment of the present invention will be first described. In one physical layer period, a frame structure for D2D broadcast communication includes one or more broadcast blocks. Each broadcast block corresponds to a plurality of subframes in the time domain, and has a plurality of resource blocks corresponding to each of the plurality of subframes, and the number of the plurality of resource blocks may be an even number. Each broadcast block includes one or more broadcast data channels, each broadcast data channel corresponding to one subframe in the time domain, and having a plurality of resource blocks corresponding to the subframe, the number of the plurality of resource blocks Can be even. The plurality of resource blocks of each broadcast block are integer multiples of a plurality of resource blocks of each broadcast data channel.

An exemplary embodiment of designing a frame structure for D2D broadcast communication in accordance with an embodiment of the present invention is shown below. First, the frame structure for D2D broadcast communication can be designed in consideration of the division and allocation of time-frequency resources. For example, for an LTE system, when resource division and allocation are performed in a time-frequency plane, the resource allocation minimum scheduling unit includes two consecutive resource blocks (RBs) within one subframe, which are referred to as resource block pairs, and whose size is, for example, It is 180k Hz x lms. A resource allocation unit for D2D broadcast communication may include a plurality of resource block pairs.

Second, the frame structure for D2D broadcast communication can be designed with the consideration of Voice over Internet Protocol (VoIP) service communication requirements. The VoIP service is periodic, and the encoder frame length is 20ms (leap seconds), that is, the voice coder generates voice packets every 20ms. The voice payload corresponding to each encoder frame is 328 bits. Therefore, in the physical layer, the resource allocation for the user equipment for broadcasting is also periodic, and this period is called a physical layer period. The physical layer period can be preset. For example, the physical layer period can be set to an integer multiple of the VoIP encoder frame length, such as 20 ms, 40 ms, and the like. The end-to-end delay limit for VoIP traffic is 200ms, which is a limit on the maximum period of resource allocation in the physical layer. In D2D broadcast communication, in order to provide a large coverage, Quadrature Phase Shift Keying (QPSK) technology can be used as a modulation scheme, and the encoding rate can be less than 1/2. Based on the above discussion, the physical layer period can be set to an integer multiple of the VoIP encoder frame length, such as 20ms, 40ms, and the like. Therefore, the minimum physical layer period can be set by the VoIP encoder frame length, for example, set to 20ms. Considering the in-band emission problem, the physical layer period can be set to 40ms.

4 is a schematic diagram 400 of a frame structure for D2D broadcast communication, in accordance with one embodiment of the present invention. 4 shows a frame structure for D2D broadcast communication on a physical layer period, the physical layer period including 40 subframes, each subframe being, for example, 1 ms. Frame structure shown in FIG 4, consists of a broadcast blocks, each block broadcast domain width _χ Ν ρ subframes of length N _F time-domain resource blocks to represent the frequency, where N _F represents a block of a physical layer broadcast period The allocated frequency resource, and N _p represents a time domain resource to which one broadcast block is allocated in one physical layer period. In an embodiment in accordance with the invention, _τ represents a time resource allocated for transmitting D2D broadcast data in one physical layer period. As shown in Fig. 4, each broadcast block is allocated Ν _ρ = 4 subframes in the time domain, so the four broadcast blocks are allocated in total in the time domain as Ν _τ = 16 subframes. In addition, each broadcast block is allocated N _F = 48 resource block frequency domain widths in the frequency domain.

According to an embodiment of the invention, each broadcast block comprises one or more broadcast data channels, each broadcast data channel representing a basic resource allocation unit represented by N _b resource block frequency domain widths X 1 subframes, where N _b denotes a frequency resource allocated to one broadcast data channel. As shown in FIG. 4, each broadcast data channel (shown by a slanted box in FIG. 4) corresponds to one subframe in the time domain, and has a plurality of resource blocks corresponding to the subframe, such as N. _b = 6.

A method for D2D broadcast communication according to an embodiment of the present invention is described below based on the above-described frame structure for D2D broadcast communication.

1 is a flow diagram of a method 100 for D2D broadcast communication in accordance with one embodiment of the present invention. The embodiment shown in Figure 1 can be performed by a user equipment or any other suitable device.

Determining a broadcast included in a frame structure for D2D broadcast communication in step S101 Information on the use of the data channel.

According to an embodiment of the present invention, in step S101, usage information of a broadcast data channel included in a frame structure can be determined in various ways. In an embodiment, it may be first determined whether there are idle subframes in multiple subframes in the frame structure, and then when there are no idle subframes in the frame structure, the used broadcast data channel in each non-idle subframe is obtained. s position. The usage information thus obtained may indicate whether there are free sub-frames in the frame structure, and may indicate the location of the used broadcast data channel within each non-idle sub-frame, and so on.

In step S102, an idle broadcast data channel is selected from the frame structure to transmit D2D broadcast data based on the determined usage information.

According to an embodiment of the present invention, when the usage information indicated in step S101 indicates that there is an idle subframe in the frame structure, one broadcast data channel in the idle subframe is selected as the idle broadcast data channel. When the usage information indicates that there is no idle subframe in the frame structure, an unused broadcast data channel in the non-idle subframe may be selected as the idle broadcast data channel according to the location of the used broadcast data channel in the non-idle subframe. , to transmit D2D broadcast data.

The idle broadcast data channel can be selected from unused broadcast data channels within the non-idle subframe in a variety of ways. For example, a non-idle subframe having the least used resource block may be searched in a non-idle subframe, and a non-idle subframe in which the signal is weakest is determined in the found non-idle subframe, and then determined to be non-idle. One unused broadcast data channel is selected in the subframe as an idle broadcast data channel for transmitting D2D broadcast data.

In addition to steps S101 and S102, as an optional step, the method 100 for D2D broadcast communication shown in FIG. 1 may further include a data retransmission process. For example, retransmission of D2D broadcast data may be performed on the same broadcast data channel as the idle broadcast data channel for each broadcast block within the physical layer period. The description of the retransmission will be further detailed in conjunction with step S205 of Fig. 2.

Further, in addition to steps S101 and S102, as another optional step, the method 100 for D2D broadcast communication shown in FIG. 1 may further include a synchronization signal transmission process. The above synchronization signals can be transmitted using a variety of implementations. About the transmission of the synchronization signal The description will be further detailed in conjunction with step S206 of FIG.

2 is a flow diagram of a method 200 for D2D broadcast communication in accordance with one embodiment of the present invention. Method 200 can be considered a specific embodiment of method 100 shown in FIG. In the following description of the method 200, how the frame structure for the D2D broadcast communication is used to acquire the use information of the broadcast data channel, and how to select the idle broadcast data channel to transmit the D2D broadcast data based on the use information. In addition, the D2D broadcast data retransmission process and the synchronization signal transmission process are also introduced. It is to be understood that the description of the invention is in the

In step S201, it is determined whether there are idle subframes in the plurality of subframes in the frame structure. When there is an idle subframe in the frame structure, the method 200 proceeds to step S202 to select a broadcast data channel within the idle subframe as the idle broadcast data channel to transmit the D2D broadcast data. When there are no free subframes in the frame structure, the method 200 proceeds to step S203 to acquire the location of the used broadcast data channel in the non-idle subframe for each non-idle subframe. Then, in step S204, an unused broadcast data channel in the non-idle subframe is selected as the idle broadcast data channel to transmit the D2D broadcast data according to the position of the used broadcast data channel in the non-idle subframe acquired in step S203.

In step S205, retransmission of the D2D broadcast data is performed on the same broadcast data channel as the idle broadcast data channel for each broadcast block within the physical layer period.

As shown in the block 1-4 of broadcast subframes allocated to broadcast data D2D Ν τ ₌ 16 subframes corresponding to the, the UE1 a broadcast data channel in the first subframe is a broadcast data D2D 4 Transmission, UE2 and UE5 perform D2D broadcast data transmission on two different broadcast data channels in the second subframe, UE3 performs D2D broadcast data transmission on one broadcast data channel in the third subframe, and UE4 is in the fourth sub- D2D broadcast data transmission is performed on one broadcast data channel in the frame. In the retransmission, UE1 is still in each broadcast block in the broadcast block corresponding to the 5-8th subframe, the broadcast block corresponding to the 9th-12th subframe, and the broadcast block corresponding to the 13th to 16th subframes. D2D broadcast data retransmission is performed on the same broadcast data channel in the first subframe (that is, the fifth subframe of all _{τ τ} subframes), and similarly, UE2-UE5 is also in the same broadcast data in each broadcast block. D2D broadcast data retransmission on the channel. In this way, time diversity can be achieved. For the receiving user equipment, the retransmitted D2D broadcast data can be received using a chase combining method.

According to an embodiment of the present invention, the number of retransmissions may be set based on a traffic load in the communication system, wherein a high number of retransmissions is set when the traffic load is large, and a low retransmission number is set when the traffic load is small. Specifically, when the traffic load is large, the user equipment receiving the D2D broadcast data may be subjected to more interference (such as collision, in-band interference, etc.), so the number of retransmissions may be set to a higher number of times. Improve the reliability and robustness of D2D broadcast communication. On the other hand, if the traffic load is small, a small number of retransmissions can be set to save the transmission power of the broadcasted user equipment and the reception power of the receiving user equipment, and also leave the same physical layer period. More available resources.

In an embodiment in accordance with the invention, the user equipment performing the broadcast may decide whether to silence the broadcast data channel for retransmission in each broadcast block. In other words, retransmissions may not be performed on each broadcast block, thereby reducing the effects of in-band leakage caused by parallel transmissions within the same subframe.

Figure 5 illustrates a schematic diagram 500 of muting a broadcast data channel to be retransmitted in a particular broadcast block, in accordance with one embodiment of the present invention. In FIG. 5, the UE 5 transmits the D2D broadcast data in one broadcast data channel in the second subframe in the first broadcast block (1st to 4th subframes), and then in the second broadcast block (5th to The same broadcast data channel (i.e., the broadcast data channel at the same position in the sixth subframe, represented by a grid-like box in the 6th subframe) can be silenced. Similarly, UE2 transmits the D2D broadcast data in one broadcast data channel in the second subframe in the first broadcast block (1st to 4th subframes), and then in the fourth broadcast block (13th to 16th subframes) The same broadcast data channel in the frame (i.e., the broadcast data channel at the same position in the 14th subframe, represented by a grid-like box) can be muted.

According to an embodiment of the present invention, whether to silence the broadcast data channel can be determined in the following manner: estimating broadcast data to be retransmitted in the broadcast block based on the traffic load in the communication system and the set number of retransmissions Channel silence And determining, based on the estimated probability, whether to silence on a broadcast data channel in the broadcast block on which retransmission is to be performed.

In step S206, in each of the broadcast blocks in the physical layer period, the synchronization signal is transmitted in the symbol of the subframe corresponding to the idle broadcast data channel.

The synchronization signal can be transmitted together with the broadcast data channel for purposes such as timing and frequency synchronization. The synchronization signal can be transmitted in any of the OFDM symbols in the subframe corresponding to the broadcast data channel. The synchronization signal may be, for example, a user equipment specific primary synchronization signal (PSS) / secondary synchronization signal (SSS), and the PSS/SSS signal may be placed in two consecutive OFDM symbols. Figure 6 shows a schematic diagram 600 of transmitting a synchronization signal in a D2D broadcast communication in accordance with one embodiment of the present invention. As shown in Figure 6, the sync signal is placed at the beginning of the sub-frame. According to an embodiment of the invention, the synchronization signal may contain information indicating a symbol in the subframe for transmitting the synchronization signal. For example, when a synchronization signal is transmitted in the 1st and 2nd OFDM symbols of a subframe, the synchronization signal may include information indicating the 1st and 2nd OFDM symbols.

According to an embodiment of the present invention, when a guard period is required at the beginning of D2D broadcast communication, the sync signal may be transmitted in a symbol following a symbol of a subframe occupied by the guard period. For example, when the first OFDM symbol of the subframe corresponds to the guard period, the PSS/SSS signal can be transmitted in the 2nd and 3rd OFDM symbols of the subframe.

As an alternative embodiment of step S206, in addition to transmitting a synchronization signal in each of the existing broadcast blocks in the physical layer period, a dedicated broadcast block may be added in the physical layer period to transmit the synchronization signal using the dedicated broadcast block. Specifically, a dedicated broadcast block may be added as a synchronization signaling region in a physical layer period; in the synchronization signaling region, a synchronization signal is transmitted using the same location corresponding to the idle broadcast data channel; and when a talk burst occurs ( When talk spurt ), a synchronization channel is established at the same location to transmit synchronization messages. The synchronization message may include a variety of information, for example, may include at least one of a D2D broadcast initiator identifier, a D2D broadcast initiator type, a modulation and coding scheme (MCS), and/or other related information.

7 is a schematic diagram 700 of transmitting a synchronization signal in a synchronization signaling region in D2D broadcast communication, in accordance with one embodiment of the present invention. As shown in FIG 7, with sub-frames of _Ν τ A dedicated broadcast block is added to the four broadcast blocks that should be used as the synchronization signaling area. Within the synchronization signaling area, the user equipment can transmit the synchronization signal using the same location corresponding to the idle broadcast data channel, at which time the D2D broadcast data is not transmitted. The D2D broadcast data is still transmitted in a broadcast data channel among four broadcast blocks corresponding to N τ subframes. For the user equipment, when a talk spurt occurs, a synchronization channel can be established at the same location in the synchronization signaling area as the idle broadcast data channel determined in method 100 to transmit the synchronization message. As shown in Figure 7, UE3 establishes a synchronization channel in the synchronization signaling area (as indicated by the box with vertical lines).

With such an embodiment, the user equipment receiving the D2D broadcast data can monitor the synchronization signaling area in each physical layer period to acquire the synchronization signal and/or the synchronization message, thereby effectively reducing the reception power consumption. At the same time, the user equipment transmitting the D2D broadcast data can also transmit the synchronization signal and/or the synchronization message only in the synchronization signaling area, which also reduces the transmission power consumption.

As another alternative embodiment of step S206, the synchronization signal may also be transmitted in a symbol following the symbol of the subframe occupied by the guard period when the protection period of the D2D broadcast communication is required. Additionally, the synchronization signal may be transmitted in any of the OFDM symbols in the synchronization signaling region that correspond to the same location of the idle broadcast data channel determined in method 100. The synchronization signal may contain information indicative of a symbol in the subframe for transmitting the synchronization signal.

Figure 8 is a diagram 800 of transmitting a synchronization signal in a synchronization signaling area in D2D broadcast communication, in accordance with another embodiment of the present invention. As shown in FIG. 8, in the synchronization signaling area, the synchronization signal of UE1 is transmitted in the OFDM symbol in the lower position of the subframe, and the synchronization signal of UE2 is transmitted in the OFDM symbol centered in the subframe, UE3 and UE5. The synchronization signal is transmitted in the first OFDM symbol in the subframe, and the synchronization signal of UE4 is transmitted in the higher OFDM symbol in the subframe.

3 is a block diagram of an apparatus 300 for D2D broadcast communication in accordance with one embodiment of the present invention. The apparatus shown in Figure 3 can be included in a user equipment or any other suitable device, or coupled directly or indirectly to a user equipment or any other suitable device.

As shown in FIG. 3, a device for D2D broadcast communication according to an embodiment of the present invention 300 includes: a determining unit 310 configured to determine usage information of a broadcast data channel included in a frame structure for D2D broadcast communication; and a selecting unit 320 configured to select from a frame structure according to the determined usage information An idle broadcast data channel to transmit D2D broadcast data.

According to an embodiment of the present invention, the frame structure may include one or more broadcast blocks in one physical layer period. Each broadcast block may correspond to a plurality of subframes in the time domain and have a plurality of resource blocks corresponding to each of the plurality of subframes. Each broadcast block may include one or more broadcast data channels, each broadcast data channel corresponding to one subframe in the time domain, and having a plurality of resource blocks corresponding to the subframe. The plurality of resource blocks that each broadcast block has may be an integer multiple of a plurality of resource blocks that each broadcast data channel has.

According to an embodiment of the present invention, the determining unit 310 may include: a determining unit configured to determine whether there are idle subframes in the plurality of subframes in the frame structure; and an obtaining unit configured to have no idleness in the frame structure In the case of a subframe, for each non-idle subframe, the location of the used broadcast data channel within the non-idle subframe is obtained.

In an embodiment of the present invention, the selecting unit 320 may include: a first channel selecting unit configured to select one broadcast data channel in the idle subframe as the idle broadcast data when there is an idle subframe in the use information indicating frame structure And a second channel selection unit configured to: when there is no idle subframe in the use information indicating frame structure, select one of the non-idle subframes according to the location of the used broadcast data channel in the non-idle subframe The broadcast data channel is used as an idle broadcast data channel.

According to an embodiment of the present invention, the second channel selection unit of the selecting unit 320 may include: a searching unit configured to search for a non-idle subframe having the least used resource block in the non-free subframe; signal strength determination a unit configured to determine a weakest non-idle subframe in the found non-free subframe; and an idle broadcast data channel selecting unit configured to select an unused broadcast data channel in the determined non-idle subframe As an idle broadcast data channel.

According to an embodiment of the present invention, an apparatus 300 for D2D broadcast communication according to an embodiment of the present invention may further include: a retransmission unit configured to be directed to an idle broadcast data channel for each broadcast block within a physical layer period The same broadcast data channel is executed against D2D Retransmission of broadcast data.

According to an embodiment of the present invention, the number of retransmissions is set based on the traffic load in the communication system, and the number of high retransmissions is set when the traffic load is large, and the low retransmission times are set when the traffic load is small.

According to an embodiment of the present invention, the retransmission unit may include: an estimating unit configured to estimate a broadcast data channel to be retransmitted in the broadcast block based on a traffic load in the communication system and a set number of retransmissions And a retransmission control unit configured to determine whether to silence on a broadcast data channel in the broadcast block on which retransmission is to be performed based on the estimated probability.

According to an embodiment of the present invention, an apparatus 300 for D2D broadcast communication according to an embodiment of the present invention may further include: a first synchronization signal transmitting unit configured to be in each broadcast block in a physical layer period, A synchronization signal is transmitted in a symbol of a subframe corresponding to the idle broadcast data channel.

According to an embodiment of the present invention, an apparatus 300 for D2D broadcast communication according to an embodiment of the present invention may further include: a dedicated broadcast block adding unit configured to add a dedicated broadcast block as a synchronization signaling area in a physical layer period; a second synchronization signal transmitting unit configured to transmit a synchronization signal by using the same location corresponding to the idle broadcast data channel in the synchronization signaling area; and a synchronization channel establishing unit configured to use when a talk burst occurs A synchronization channel is established at the same location to transmit synchronization messages.

According to an embodiment of the present invention, the synchronization message may include at least one of the following: a D2D broadcast initiator identifier, a D2D broadcast initiator type, a modulation and coding scheme.

According to an embodiment of the present invention, when a guard period is required at the beginning of D2D broadcast communication, a sync signal is transmitted in a symbol following a symbol of a subframe occupied by the guard period.

According to an embodiment of the present invention, the synchronization signal may include information indicating a symbol for transmitting a synchronization signal in the subframe.

It should be understood that the structural block diagrams illustrated in Figures 3 and 4 are shown for illustrative purposes only and are not limiting of the invention. For the sake of clarity, some of the optional units and subunits of device 300 are not shown in FIG. In some cases, some of the cells/subunits may be added or subtracted as needed. However, it should be understood that reference is made to Figure 1 above. The various features depicted in FIG. 2 are equally applicable to device 300. Moreover, the term "unit" as used herein may be either a hardware module or a software unit module. Accordingly, device 300 can be implemented in a variety of ways. For example, in some embodiments, a device may be implemented in part or in whole using software and/or firmware, such as a computer program product embodied on a computer readable medium. Alternatively or additionally, the apparatus may be implemented partially or entirely based on hardware, such as an integrated circuit (IC), an application specific integrated circuit (ASIC), a system on a chip (SOC), a field programmable gate array (FPGA), and the like. The scope of the invention is not limited in this respect.

Additionally, embodiments of the invention may include a physical device that includes the above described apparatus. For example, the present invention can be implemented as a user device comprising the apparatus 300 described above, including but not limited to a cellular telephone, a mobile telephone, a personal digital assistant (PDA), a tablet capable of communication, or any suitable fixation and/or Mobile devices.

Several exemplary embodiments of the invention have been described above for illustrative purposes only. Embodiments of the invention may be implemented in hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated design hardware. One of ordinary skill in the art will appreciate that the systems and methods described above can be implemented using computer-executable instructions and/or embodied in processor control code, such as a carrier medium such as a magnetic disk, CD or DVD-ROM, such as a read only memory. Such code is provided on a programmable memory (firmware) or on a data carrier such as an optical or electronic signal carrier. The system of the present invention may be implemented by a hardware circuit such as a very large scale integrated circuit or gate array, a semiconductor such as a logic chip, a transistor, or the like, or a programmable hardware device such as a field programmable gate array, a programmable logic device, or the like, or may be used by Software implementations of various types of processor executions may also be implemented by a combination of the above-described hardware circuits and software, such as firmware.

It should be noted that although several devices or sub-devices of the system are mentioned in the detailed description above, such division is merely not mandatory. Indeed, in accordance with embodiments of the present invention, the features and functions of the two or more devices described above may be embodied in one device. Conversely, the features and functions of one of the devices described above can be further divided into multiple Set to be specific. Similarly, although the operation of the method of the present invention is described in a particular order in the figures, this is not a requirement or implied that the operations must be performed in that particular order, or that all of the illustrated operations must be performed to achieve the desired results. Instead, the steps depicted in the flowcharts can change the order of execution. Additionally or alternatively, certain steps may be omitted, multiple steps being combined into one step, and/or one step being broken down into multiple steps.

Although the invention has been described with reference to a particular embodiment thereof, it is understood that the invention is not limited to the specific embodiments disclosed. The invention is intended to cover various modifications and equivalent arrangements and The scope of the following claims is to be accorded

Claims

Claim

A method for device-to-device D2D communication, comprising:

Determining usage information of a broadcast data channel included in a frame structure for D2D broadcast communication;

Based on the determined usage information, an idle broadcast data channel is selected from the frame structure to transmit D2D broadcast data.

2. The method of claim 1, wherein the frame structure comprises one or more broadcast blocks in one physical layer period,

Each of the broadcast blocks corresponds to a plurality of subframes in the time domain, and has a plurality of resource blocks corresponding to each of the plurality of subframes,

Wherein each broadcast block includes one or more broadcast data channels, each broadcast data channel corresponding to one subframe in the time domain, and having a plurality of resource blocks corresponding to the subframe, and

Each of the plurality of resource blocks that each broadcast block has is an integer multiple of a plurality of resource blocks per broadcast data channel.

3. The method according to claim 1, wherein determining usage information of a broadcast data channel included in a frame structure for D2D broadcast communication comprises:

Determining whether there are idle subframes in the multiple subframes in the frame structure; and when there are no idle subframes in the frame structure, acquiring used in the non-idle subframes for each non-idle subframe The location of the broadcast data channel.

4. The method of claim 1, wherein selecting an idle broadcast data channel from the frame structure to transmit D2D broadcast data according to the determined usage information comprises: when the usage information indicates the presence in the frame structure When the idle subframe is idle, selecting one broadcast data channel in the idle subframe as the idle broadcast data channel;

When the usage information indicates that there is no idle subframe in the frame structure, selecting an unused broadcast data channel in the non-idle subframe as the location according to the location of the used broadcast data channel in the non-idle subframe The idle broadcast data channel.

5. The method of claim 4, wherein selecting an unused broadcast data channel within the non-idle subframe as the idle broadcast data channel comprises:

Finding a non-idle subframe having the least used resource block in the non-idle subframe;

Determining a non-idle subframe of the weakest signal in the non-idle subframe found; and selecting an unused broadcast data channel as the idle broadcast data channel in the determined non-idle subframe.

6. The method of claim 1 further comprising:

Retransmission of the D2D broadcast data is performed on the same broadcast data channel as the idle broadcast data channel for each broadcast block within the physical layer period.

7. The method of claim 6, wherein the number of retransmissions is set based on traffic load in a communication system, and

The high retransmission times are set when the traffic load is large, and the low retransmission times are set when the traffic load is small.

8. The method of claim 6, wherein performing retransmission of the D2D broadcast data on a broadcast data channel identical to the idle broadcast data channel for each broadcast block within a physical layer period comprises:

Estimating a probability of silence of the broadcast data channel in the broadcast block to be retransmitted based on the traffic load and the set number of retransmissions in the communication system;

Based on the estimated probability, it is decided whether to silence on the broadcast data channel in the broadcast block where retransmission is to be performed.

9. The method of claim 1 further comprising:

In each broadcast block in the physical layer period, a synchronization signal is transmitted in a symbol of a subframe corresponding to the idle broadcast data channel.

10. The method of claim 1, further comprising:

Adding a dedicated broadcast block as a synchronization signaling area in the physical layer period;

Transmitting a synchronization signal using the same location corresponding to the idle broadcast data channel in the synchronization signaling region;

When a talk spurt occurs, a synchronization channel is established by using the same location to transmit synchronization Message.

11. The method of claim 10, wherein the synchronization message comprises at least one of: a D2D broadcast initiator identifier, a D2D broadcast initiator type, and a modulation and coding scheme.

The method according to any one of claims 9 to 11, wherein when a guard period is required at the beginning of the D2D broadcast communication, a symbol is transmitted in a symbol following a symbol of a subframe occupied by the guard period Said synchronization signal.

13. The method of claim 11 wherein the synchronization signal includes information indicative of a symbol in a subframe for transmitting the synchronization signal.

14. An apparatus for device-to-device D2D communication, comprising:

a determining unit configured to determine usage information of a broadcast data channel included in a frame structure for D2D broadcast communication;

The selection unit is configured to select an idle broadcast data channel from the frame structure to transmit D2D broadcast data based on the determined usage information.

15. The apparatus of claim 14, wherein the frame structure comprises one or more broadcast blocks in one physical layer period,

16. The apparatus according to claim 14, wherein the determining unit comprises: a determining unit configured to determine whether an idle subframe exists in a plurality of subframes in the frame structure;

And an acquiring unit, configured to: when there is no idle subframe in the frame structure, acquire, for each non-idle subframe, a location of the used broadcast data channel in the non-idle subframe.

17. The apparatus according to claim 14, wherein the selecting unit comprises: a first channel selecting unit configured to select the idle subframe when the usage information indicates that there is an idle subframe in the frame structure One of the broadcast data channels as the idle broadcast data channel;

a second channel selection unit, configured to: when the usage information indicates that there is no idle subframe in the frame structure, select the non-idle subframe according to a location of a used broadcast data channel in the non-idle subframe One unused broadcast data channel is used as the idle broadcast data channel.

18. The apparatus of claim 17, wherein the second channel selection unit comprises:

a searching unit configured to look up a non-idle subframe having the least used resource block in the non-idle subframe;

a signal strength determining unit configured to determine a non-idle subframe in which the weakest signal in the non-idle subframe is found; and

The idle broadcast data channel selecting unit is configured to select an unused broadcast data channel as the idle broadcast data channel among the determined non-idle subframes.

19. The apparatus of claim 14, further comprising:

The retransmission unit is configured to perform retransmission of the D2D broadcast data on the same broadcast data channel as the idle broadcast data channel for each broadcast block within the physical layer period.

20. The apparatus of claim 19, wherein the number of retransmissions is set based on a traffic load in a communication system, and

21. The apparatus according to claim 19, wherein the retransmission unit comprises: an estimating unit configured to estimate a retransmission to be performed on a broadcast block based on a traffic load in the communication system and a set number of retransmissions The probability that the broadcast data channel is silent; and

a retransmission control unit configured to determine whether to be in the wide area based on the estimated probability Silence is performed on the broadcast data channel in the broadcast block where retransmission is to be performed.

22. The apparatus of claim 14, further comprising:

a first synchronization signal transmitting unit configured to transmit a synchronization signal in a symbol of a subframe corresponding to the idle broadcast data channel in each broadcast block in a physical layer period

23. The apparatus of claim 14, further comprising:

a dedicated broadcast block adding unit configured to add a dedicated broadcast block as a synchronization signaling area in a physical layer period;

a second synchronization signal transmitting unit configured to transmit a synchronization signal using the same location corresponding to the idle broadcast data channel in the synchronization signaling region;

The synchronization channel establishing unit is configured to establish a synchronization channel using the same location to transmit a synchronization message when a talk burst occurs.

24. The apparatus of claim 23, wherein the synchronization message comprises at least one of: a D2D broadcast initiator identifier, a D2D broadcast initiator type, and a modulation and coding scheme.

The apparatus according to any one of claims 22-24, wherein when a guard period is required at the beginning of the D2D broadcast communication, a symbol is transmitted in a symbol following a symbol of a subframe occupied by the guard period Said synchronization signal.

26. The apparatus of claim 24, wherein the synchronization signal comprises information indicative of a symbol in a subframe for transmitting the synchronization signal.

A user equipment comprising the apparatus according to any one of claims 14 to 26.