CN109309928B

CN109309928B - D2D link detection method, related device and system

Info

Publication number: CN109309928B
Application number: CN201710617012.2A
Authority: CN
Inventors: 王旭东; 黄程; 翟邦昭; 唐爱民; 张弛
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-07-26
Filing date: 2017-07-26
Publication date: 2021-01-29
Anticipated expiration: 2037-07-26
Also published as: CN109309928A

Abstract

The application discloses a D2D link detection method, which comprises the steps that a first terminal sends a data signal and a first control signal to a second terminal; the first control signal carries indication information of feedback time, and is used for indicating the second terminal to send a feedback signal to the first terminal at the feedback time; the feedback signal is sent to the first terminal by the second terminal after receiving the data signal; and if the first terminal receives the feedback signal sent by the second terminal at the feedback time, judging that the D2D link between the first terminal and the second terminal is normal. The scheme can realize the rapid detection of the D2D link failure.

Description

D2D link detection method, related device and system

Technical Field

The present application relates to the field of wireless communication technologies, and in particular, to a D2D link detection method, a related apparatus and a system.

Background

In order to implement proximity communication, a device to device (D2D) communication technology called proximity service (ProSe) is introduced in the 3GPP standard Release 12. The D2D technique was further enhanced in Release 13 and Release 14. In the 3GPP standard (TS 36.213), D2D transmission occupies uplink spectrum resources for cellular communication, and performs D2D communication with a sidelink control period (SC period) as a period. As shown in fig. 1, one SC period includes one PSCCH period and one PSCCH period, D2D communication resources on the PSCCH period are used to carry D2D Control (Control) signals (e.g., Sidelink Control Information (SCI)), and D2D communication resources on the PSCCH period are used to carry D2D Data (Data) signals.

In D2D communication, the sender knows the proximity service Layer 2Group identity (ProSe Layer-2Group ID) of the receiver. The ProSe Layer-2Group ID is an identification code used in the physical Layer to identify and select recipients. When the transmitting end has data to transmit, the transmitting end transmits an SCI message through a physical sidelink physical control channel (PSCCH) to inform the receiving end of a timing adjustment amount required for correctly receiving the data, a resource block occupied by the data in a physical sidelink shared channel (PSCCH), and a Modulation and Coding Scheme (MCS). Then, on the corresponding PSSCH time frequency resource, the transmitting end will adopt a hybrid automatic repeat request (HARQ) form to transmit data, and the modes are 0, 2, 3, and 1, respectively. Accordingly, the receiving end knows that there is data to be sent to itself by detecting the PSCCH. Then, the receiving end receives data on the resources agreed in the psch according to the timing adjustment amount and MCS and other information notified from the transmitting end, but does not perform HARQ feedback.

As known from the existing standard (TR 22.803), the application scenario of the D2D technology mainly includes public safety, proximity advertisement push and social network. In the three application scenarios, the data transmission amount of the D2D is small, and the requirement on the data transmission quality is not high. For these three application scenarios, the existing ProSe standard only designs Keepalive mechanism (which can refer to standard TS 24.334) of the application layer to maintain the transmission link. With the increase of communication requirements and the tension of spectrum resources, the application scenario of the D2D communication technology can be extended to the following data transmission scenarios, including: 1) the D2D communication is used between two adjacent users to realize one-hop high-speed data transmission; 2) two users who are not within the proximity communication range perform data transmission using multi-hop D2D communication.

Due to the existence of external interference and mutual movement between nodes, the D2D link has the possibility of breaking. Blind transmission of data under link failure conditions will result in waste of communication resources and increase of data transmission delay. Therefore, the link failure detection mechanism is very important for D2D communication. However, the detection delay of the Keepalive mechanism designed by the existing ProSe standard is large, which is not beneficial to quickly detecting the D2D link failure.

Disclosure of Invention

The application provides a D2D link detection method, a related device and a system, which can realize the rapid detection of D2D link faults.

In a first aspect, the present application provides a D2D link detection method, applied to a first terminal, where the method may include: the first terminal sends a data signal and a first control signal to the second terminal. The first control signal carries indication information of feedback time, and is used for indicating the second terminal to send a feedback signal to the first terminal at the feedback time. The feedback signal is sent by the second terminal to the first terminal after receiving the data signal. And if the first terminal receives the feedback signal sent by the second terminal at the feedback time, judging that the D2D link between the first terminal and the second terminal is normal.

In a second aspect, the present application provides a D2D link detection method, applied to a second terminal, where the method may include: and if the second terminal receives the data signal and the first control signal sent by the first terminal, the second terminal sends a feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal. Otherwise, the second terminal does not send the feedback signal. And the indication information of the feedback time is used for indicating the second terminal to send the feedback signal to the first terminal at the feedback time.

Implementing the D2D link detection methods described in the first and second aspects, the first terminal may instruct the second terminal to return a feedback signal at the feedback time, so that the D2D link status can be detected quickly.

In this application, the feedback time may be indicated by the time of a timer, that is, the indication information of the feedback time may be the time information of the timer. Here, the timer may be referred to as a failure detection timer. Specifically, the time of the failure detection timer may be expressed as at least one SC period plus one PSCCH period, i.e., n × SC period + PSCCH, where n is a positive integer.

Specifically, the initial time of the failure detection timer may be set by the sending end, or may be set by a network device (e.g., a base station). The initial time of the failure detection timer may be related to the size of the data transfer amount. The larger the data transfer amount, the larger the initial time of the failure detection timer. The smaller the data transfer amount, the smaller the initial time of the failure detection timer.

In this application, an SC period may be referred to as a first time interval, a PSCCH period in the SC period may be referred to as a second time interval, and a PSCCH period in the SC period may be referred to as a third time interval. In this application, the D2D communication resource that a network device (e.g., a base station) may allocate to a first terminal and a second terminal is referred to as a first communication resource. The first communication resource in the second time interval is used for carrying the first control signal, and the first communication resource in the third time interval is used for carrying the data signal.

In this application, the first control signal may be a new PSCCH signaling.

Specifically, SCI signaling may be extended to implement the new PSCCH signaling, that is, the new PSCCH signaling may be new SCI signaling. Specifically, a new field, such as a link failure detection timer field, may be added on the basis of the existing SCI signaling to form a new SCI signaling. The new field may represent the time (unit may be millisecond) of the failure detection timer by 8 bits (not limited to 8 bits).

In the present application, the feedback signal can be implemented in the following two ways.

First, the feedback signal may be the new SCI signaling (i.e. the first control signal), and one or more fields in the new SCI signaling are special values (e.g. 0).

For example, setting one or more fields in the above-mentioned new SCI signaling to 0 may constitute the feedback signal SCI _ linkalive. For example, all bits of the link failure detection timer field may be set to 0, or all bits of fields such as resource block allocation, frequency hopping resource allocation, time domain resource pattern, timing advance indication, and the like may be set to 0. The example is only one embodiment provided in this application, and in practical applications, not limited to the specific value 0, one or more fields in the feedback signal SCI _ linear may also be set to other specific values, which is not limited herein.

In the first implementation manner, the second terminal may return a feedback signal SCI _ linear to the first terminal through a control channel (e.g., PSCCH) at the feedback time.

It should be noted that, not limited to extending SCI signaling, the feedback signal related to the present application may also be implemented by extending other PSCCH signaling. The data format of PSCCH signaling (including SCI signaling) is not limited to that specified by existing standards, and future communication systems, such as 5G or New Radio (NR) communication systems, may have changed in their specification of PSCCH signaling (including SCI signaling), and the present application is equally applicable to such changes.

Second, the feedback signal may be a special MAC layer data frame, which may be called a MAC layer linkalive frame. The payload (payload) of the MAC layer linkalive frame may be a special value. The frame structure of the MAC layer linkalive frame may follow the frame structure of an existing secondary link shared channel (SL-SCH).

For example, the payload of the MAC layer linkalive frame may be a special value, such as the sequence 01010111. The examples are only used for explaining the present application, and in practical applications, the payload of the MAC layer linkalive frame may also be set to other special values, which is not limited herein.

In the second implementation manner, the second terminal may return the MAC layer linkalive frame to the first terminal through a data channel (e.g., psch) at the feedback time.

In the second implementation manner, in addition to the MAC layer linkalive frame, the second terminal needs to send SCI signaling to the first terminal for indicating the resources occupied by the MAC layer linkalive frame in the data channel (e.g., psch) and the transmission policy (e.g., MCS), so that the first terminal can correctly receive the feedback signal. This SCI signaling may be referred to herein as a second control signal.

In one link detection scenario, the link between the first terminal and the second terminal is normal. The second terminal may receive the data signal sent by the first terminal and initiate feedback. Specifically, the second terminal may transmit a feedback signal to the first terminal at the feedback time. In this way, the first terminal can receive the feedback signal at the feedback time, thereby determining that the link between the first terminal and the second terminal is normal.

In another link detection scenario, a link between a first terminal and a second terminal fails. The second terminal does not receive the data signal sent by the first terminal and does not perform feedback. Therefore, the first terminal cannot receive the feedback signal at the feedback time, namely, the first terminal enters a fault early warning state. Such a failure may be a transient failure that can quickly recover to a normal state.

In some optional embodiments, when a link failure is first discovered, the first terminal may first determine that the link enters a failure early warning state, and then determine whether the link fails again through a failure early warning process. The link early warning procedure can be summarized as follows:

(1) after the link fails and enters a failure early warning state, the first terminal reconfigures the initial time of the link detection timer. The initial time for reconfiguration may be less than the initial time configured for the link detection timer before entering the failure early warning state, facilitating to quickly confirm whether the link is failed. Then, the first terminal may resend the data signal and the first control signal to the second terminal with the SC period as a period. In each SC period, the retransmitted first control signal carries a link detection timer time, which is used to indicate a feedback time for the second terminal to return a feedback signal.

(2) If the first terminal receives a feedback signal returned by the second terminal within the feedback time of the feedback signal, the first terminal may determine that the link between the first terminal and the second terminal is recovered to be normal, otherwise, the first terminal may finally determine that the link between the first terminal and the second terminal is failed.

In this application, the second terminal may send the feedback signal to the first terminal in the following two ways:

first, the second terminal may transmit the feedback signal SCI _ linear to the first terminal through the secondary link control channel PSCCH at the feedback time.

In a second manner, the second terminal may send a feedback signal MAC layer linkalive frame to the first terminal through the secondary link shared channel psch at the feedback time.

In a third aspect, the present application provides a communication device, which is the above-mentioned first terminal, and the communication device may include a plurality of functional modules for correspondingly performing the method provided by the first aspect, or the method provided by any one of the possible implementations of the first aspect.

In a fourth aspect, the present application provides a communication device, which is the second terminal described above, and which may include a plurality of functional modules for correspondingly performing the method provided in the second aspect, or the method provided in any one of the possible implementations of the second aspect.

In a fifth aspect, the present application provides a communication apparatus, which is the first terminal described above, for performing the D2D link detection method described in the first aspect. The communication device may include: a memory and a processor, transceiver coupled with the memory, wherein: the transceiver is used for communicating with other communication devices, such as terminals or network devices. The memory is configured to store implementation code of the D2D link detection method described in the first aspect, and the processor is configured to execute the program code stored in the memory, that is, to execute the method provided by the first aspect, or the method provided by any one of the possible implementations of the first aspect.

In a sixth aspect, the present application provides a communication apparatus, which is the second terminal described above, for executing the D2D link detection method described in the second aspect. The communication device may include: a memory and a processor, transceiver coupled with the memory, wherein: the transceiver is used for communicating with other communication devices, such as terminals or network devices. The memory is used for storing implementation codes of the D2D link detection method described in the second aspect, and the processor is used for executing the program codes stored in the memory, that is, executing the method provided by the second aspect, or the method provided by any one of the possible implementation modes of the second aspect.

In a seventh aspect, the present application provides a wireless communication system, including a first terminal and a second terminal, wherein:

the first terminal is used for sending a data signal and a first control signal to the second terminal. The first control signal carries indication information of feedback time, and is used for indicating the second terminal to send a feedback signal to the first terminal at the feedback time. The first terminal is further configured to determine that the D2D link between the first terminal and the second terminal is normal if the feedback signal sent by the second terminal is received at the feedback time.

And the second terminal is used for sending a feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal if the data signal and the first control signal sent by the first terminal are received, otherwise, the second terminal does not send the feedback signal.

Specifically, the first terminal may be the communication apparatus described in the third aspect, and the second terminal may be the communication apparatus described in the fourth aspect. Specifically, the first terminal may also be the communication apparatus described in the fifth aspect, and the second terminal may also be the communication apparatus described in the sixth aspect.

In an eighth aspect, a computer-readable storage medium is provided, where the computer-readable storage medium stores program code for implementing the D2D link check method provided in the first aspect, or the D2D link check method provided in any one of the possible implementations of the first aspect, and the program code includes instructions for executing the D2D link check method provided in the first aspect, or the D2D link check method provided in any one of the possible implementations of the first aspect.

In a ninth aspect, a computer-readable storage medium is provided, where the computer-readable storage medium stores program code for implementing the D2D link check method provided in the second aspect or the D2D link check method provided in any one of the possible implementation manners of the second aspect, and the program code includes instructions for executing the D2D link check method provided in the second aspect or the D2D link check method provided in any one of the possible implementation manners of the second aspect.

In connection with the tenth aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the D2D link detection method described above in the first aspect.

In connection with the eleventh aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the D2D link detection method described in the second aspect above.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings required to be used in the embodiments or the background art of the present application will be described below.

Fig. 1 is a schematic diagram of D2D communication resources to which the present application relates;

fig. 2 is an architecture diagram of a wireless communication system to which the present application relates;

fig. 3 is a schematic hardware architecture diagram of a terminal provided by an embodiment of the present application;

fig. 4 is a schematic hardware architecture diagram of a base station according to an embodiment of the present application;

FIG. 5 is a diagram of a data structure for a new SCI signaling provided herein;

FIG. 6 is a schematic diagram of a data structure of a feedback signal provided herein;

FIG. 7 is a schematic diagram of another data structure for a feedback signal provided herein;

8A-8C are schematic flow diagrams of a D2D link detection method provided by an embodiment of the present application;

9A-9C are schematic flow diagrams of a D2D link detection method according to another embodiment of the present application;

fig. 10 is a functional block diagram of a wireless communication system and a communication device according to the present application.

Detailed Description

The terminology used in the description of the embodiments section of the present application is for the purpose of describing particular embodiments of the present application only and is not intended to be limiting of the present application.

Fig. 2 shows a wireless communication system to which the present application relates. The wireless communication system may be a Long Term Evolution (LTE) system, or a future-Evolution fifth-Generation mobile communication (5G) system, a new air interface (NR) system, a Machine-to-Machine communication (M2M) system, or the like. As shown in fig. 2, the wireless communication system 100 may include: one or more network devices 101, one or more pairs of D2D terminals 103. Wherein:

under the condition that the network device 101 has D2D communication requirements in a cell, the control of D2D communication can be completed through signaling interaction, communication resources are allocated to D2D users, and the D2D link state is monitored. The network device 101 may be a base station, and the base station may be configured to communicate with one or more terminals, and may also be configured to communicate with one or more base stations having partial terminal functions (e.g., communication between a macro base station and a micro base station, such as an access point). The Base Station may be a Base Transceiver Station (BTS) in a Time Division Synchronous Code Division Multiple Access (TD-SCDMA) system, an evolved Node B (eNB) in an LTE system, and a Base Station in a 5G system or a new air interface (NR) system. In addition, the base station may also be an Access Point (AP), a transmission node (Trans TRP), a Central Unit (CU), or other network entity, and may include some or all of the functions of the above network entities.

The terminal 103 may receive signaling from the network device 101, perform transmission of channel sounding signals, detect channel quality, and perform data transmission according to the D2D mode selected by the network device 101 and the allocated resources. In the data transmission process, the terminal 103 may detect the link status of D2D, and report the link failure information to the network device 101 in time. For a pair of D2D terminals 103 within the coverage of network device 101, under the control and management of network device 101, one terminal 103 may transmit data to the other terminal 103 using D2D communications. The terminals 103 may be distributed throughout the wireless communication system 100 and may be stationary or mobile. In some embodiments of the present application, the terminal 103 may be a mobile device, mobile station (mobile station), mobile unit (mobile unit), M2M terminal, wireless unit, remote unit, user agent, mobile client, or the like.

It should be noted that the wireless communication system 100 shown in fig. 2 is only for more clearly illustrating the technical solution of the present application, and does not constitute a limitation to the present application, and as a person having ordinary skill in the art knows, the technical solution provided in the present application is also applicable to similar technical problems as the network architecture evolves and new service scenarios emerge.

Referring to fig. 3, fig. 3 illustrates a terminal 200 provided by some embodiments of the present application. As shown in fig. 3, the terminal 200 may include: one or more terminal processors 201, memory 202, communication interface 203, receiver 205, transmitter 206, coupler 207, antenna 208, user interface 202, and input-output modules (including audio input-output module 210, key input module 211, and display 212, etc.). These components may be connected by a bus 204 or otherwise, as illustrated in FIG. 3 by a bus connection. Wherein:

the communication interface 203 may be used for the terminal 200 to communicate with other communication devices, such as other terminals or network devices. Specifically, the communication interface 203 may be a D2D communication interface, may also be a Long Term Evolution (LTE) (4G) communication interface, and may also be a communication interface of a 5G or future new air interface. Not limited to the wireless communication interface, the terminal 200 may also be configured with a wired communication interface 203, such as a Local Access Network (LAN) interface.

Transmitter 206 may be used to perform transmit processing, e.g., signal modulation, on the signal output by terminal processor 201. The receiver 205 may be used for performing receive processing, such as signal demodulation, on the mobile communication signal received by the antenna 208. In some embodiments of the present application, the transmitter 206 and the receiver 205 may be considered as one wireless modem. In the terminal 200, the number of the transmitters 206 and the receivers 205 may be one or more. The antenna 208 may be used to convert electromagnetic energy in the transmission line to electromagnetic energy in free space, or vice versa. The coupler 207 is used to divide the mobile communication signal received by the antenna 208 into a plurality of paths and distribute the plurality of paths to the plurality of receivers 205.

In addition to the transmitter 206 and receiver 205 shown in fig. 3, the terminal 200 may also include other communication components, such as a GPS module, a Bluetooth (Bluetooth) module, a Wireless Fidelity (Wi-Fi) module, and so on. Not limited to the above-expressed wireless communication signals, the terminal 200 may also support other wireless communication signals, such as satellite signals, short-wave signals, and so forth. Not limited to wireless communication, the terminal 200 may also be configured with a wired network interface (e.g., a LAN interface) to support wired communication.

The input and output module may be used to enable interaction between the terminal 200 and a user/external environment, and may mainly include an audio input and output module 210, a key input module 211, a display 212, and the like. Specifically, the input/output module may further include: cameras, touch screens, sensors, and the like. Wherein the input and output modules are in communication with the terminal processor 201 through the user interface 209.

Memory 202 is coupled to terminal processor 201 for storing various software programs and/or sets of instructions. In particular, the memory 202 may include high speed random access memory, and may also include non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory 202 may store an operating system (hereinafter referred to simply as a system), such as an embedded operating system like ANDROID, IOS, WINDOWS, or LINUX. The memory 202 may also store a network communication program that may be used to communicate with one or more additional devices, one or more terminal devices, one or more network devices. The memory 202 may further store a user interface program, which may vividly display the content of the application program through a graphical operation interface, and receive a control operation of the application program from a user through input controls such as menus, dialog boxes, and buttons.

In some embodiments of the present application, the memory 202 may be used to store an implementation program of the D2D link detection method provided by one or more embodiments of the present application on the terminal 200 side. For implementation of the D2D link detection method provided in one or more embodiments of the present application, please refer to the following embodiments.

The terminal processor 201 is operable to read and execute computer readable instructions. Specifically, the terminal processor 201 may be configured to invoke a program stored in the memory 212, for example, an implementation program of the D2D link detection method provided in one or more embodiments of the present application on the terminal 200 side, and execute instructions contained in the program.

It is understood that the terminal 200 may be the terminal 103 in the wireless communication system 100 shown in fig. 2, and may be implemented as a mobile device, a mobile station (mobile station), a mobile unit (mobile unit), a wireless unit, a remote unit, a user agent, a mobile client, or the like.

It should be noted that the terminal 200 shown in fig. 3 is only one implementation manner of the embodiment of the present application, and in practical applications, the terminal 200 may further include more or less components, which is not limited herein.

Referring to fig. 4, fig. 4 illustrates a network device 300 provided by some embodiments of the present application. As shown in fig. 4, the network device 300 may include: one or more network device processors 301, memory 302, communication interface 303, transmitter 305, receiver 306, coupler 307, and antenna 308. These components may be connected by a bus 304, or otherwise, as illustrated in FIG. 4 by way of example. Wherein:

the communication interface 303 may be used for the network device 300 to communicate with other communication devices, such as terminals or other network devices. Specifically, the communication interface 203 of the communication interface 303 may be a Long Term Evolution (LTE) (4G) communication interface, or may be a communication interface of a 5G or future new air interface. Not limited to wireless communication interfaces, network device 300 may also be configured with a wired communication interface 303 to support wired communication, e.g., a backhaul link between one network device 300 and other network devices 300 may be a wired communication connection.

Transmitter 305 may be used to perform transmit processing, e.g., signal modulation, on the signal output by network device processor 301. Receiver 306 may be used for receive processing of mobile communication signals received by antenna 308. Such as signal demodulation. In some embodiments of the present application, the transmitter 305 and the receiver 306 may be considered as one wireless modem. In the network device 300, the number of the transmitters 305 and the receivers 306 may be one or more. The antenna 308 may be used to convert electromagnetic energy in the transmission line to electromagnetic energy in free space or vice versa. Coupler 307 may be used to multiplex the mobile communications signal to a plurality of receivers 306.

Memory 302 is coupled to network device processor 301 for storing various software programs and/or sets of instructions. In particular, the memory 302 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory 302 may store an operating system (hereinafter, referred to as a system), such as an embedded operating system like uCOS, VxWorks, RTLinux, etc. The memory 302 may also store a network communication program that may be used to communicate with one or more additional devices, one or more terminal devices, one or more network devices.

Network device processor 301 may be configured to perform radio channel management, implement call and communication link setup and teardown, provide cell switching control for users within the control area, and the like. Specifically, the network device processor 301 may include: an Administration/Communication Module (AM/CM) (a center for voice channel switching and information switching), a Basic Module (BM) (for performing call processing, signaling processing, radio resource management, management of radio links, and circuit maintenance functions), a code conversion and sub-multiplexing unit (TCSM) (for performing multiplexing/demultiplexing and code conversion functions), and so on.

In embodiments of the present application, the network device processor 301 may be configured to read and execute computer readable instructions. Specifically, the network device processor 301 may be configured to call a program stored in the memory 302, for example, an implementation program of the D2D link detection method provided in one or more embodiments of the present application on the network device 300 side, and execute instructions contained in the program.

It is understood that the network device 300 may be the network device 101 in the wireless communication system 100 shown in fig. 2, and may be implemented as a base transceiver station, a wireless transceiver, a Basic Service Set (BSS), an Extended Service Set (ESS), a NodeB, an eNodeB, an access point or a TRP, etc.

It should be noted that the network device 300 shown in fig. 4 is only one implementation manner of the embodiment of the present application, and in practical applications, the network device 300 may further include more or less components, which is not limited herein.

Based on the foregoing embodiments corresponding to the wireless communication system 100, the terminal 200, and the network device 300, respectively, the present embodiment provides a D2D link detection method.

The main inventive principles of the present application may include: for a pair of terminals in D2D communication, the sending end sends a new PSCCH signaling to the receiving end, where the signaling carries indication information (timer time) of the feedback time for instructing the receiving end to return a feedback signal at the feedback time (for informing the receiving end at what time to return the feedback signal). Specifically, if the receiving end receives the data signal sent by the sending end, the receiving end may return a feedback signal to the sending end at the feedback time; otherwise, the sending end does not return a feedback signal to the sending end. The transmitting end may determine whether a link between the transmitting end and the receiving end is normal according to whether the feedback signal is received. The link detection mechanism provided by the application can realize the rapid detection of the D2D link failure.

In this application, the feedback time may be indicated by the time of a timer, that is, the indication information of the feedback time may be the time information of the timer. Here, the timer may be referred to as a failure detection timer. Specifically, the time of the failure detection timer may be expressed as at least one SC period plus one PSCCH period, i.e., n × SC period + PSCCH, where n is a positive integer. The feedback time indicated by the time of the failure detection timer is the SC Period next to the last SC Period in n SC periods. Here, one PSCCH period is a time domain period for transmitting or receiving one PSCCH signaling, i.e., a transmission period of PSCCH signaling (e.g., SCI signaling).

In this application, an SC period may be referred to as a first time interval, a PSCCH period in the SC period may be referred to as a second time interval, and a PSCCH period in the SC period may be referred to as a third time interval. In this application, the D2D communication resource (shown in fig. 1) that a network device (e.g., a base station) allocates to a first terminal and a second terminal may be referred to as a first communication resource. The first communication resource in the second time interval is used for carrying the first control signal, and the first communication resource in the third time interval is used for carrying the data signal.

In this application, the new PSCCH signaling may be referred to as a first control signal.

Specifically, SCI signaling may be extended to implement the new PSCCH signaling, that is, the new PSCCH signaling may be new SCI signaling. As shown in fig. 5, a new field, such as a "Link failure detection timer" field in fig. 5, may be added on the basis of the existing SCI signaling to form a new SCI signaling. The new field may represent the time (unit may be millisecond) of the failure detection timer by 8 bits (not limited to 8 bits). In this application, this new field may be referred to as a first field. In addition, the meaning of other fields in SCI signaling is as follows: a Frequency hopping flag bit (Frequency hopping flag) indicates whether the D2D communication adopts a Frequency hopping technology; resource block allocation and frequency hopping Resource allocation (Resource block allocation and hopping Resource allocation) represents carrier frequency Resource blocks and frequency hopping Resource allocation used by the D2D communication; a Time domain resource pattern (Time resource pattern) represents a subframe to which D2D communication is mapped; a Modulation and Coding Scheme (MCS) indicates a modulation order and a coding scheme adopted for transmission of a data signal; timing advance indication (Timing advance indication) represents the Timing advance required by a receiving end in D2D communication; the Group address identification (Group destination ID) indicates the address of the Group to which the sink belongs in the D2D communication.

In addition, the present application also defines the above feedback signal. Specifically, the feedback signal can be realized in the following two ways.

First, the feedback signal may be the new SCI signaling shown in fig. 5, and one or more fields in the new SCI signaling are special values (e.g., 0).

For example, setting one or more fields to 0 in the new SCI signaling shown in fig. 5 may constitute the feedback signal SCI _ linkalive shown in fig. 6. Specifically, all bits of the link failure detection timer field may be set to 0, or all bits of fields such as resource block allocation, frequency hopping resource allocation, time domain resource pattern, timing advance indication, and the like may be set to 0. Since the feedback signal SCI _ linkalive does not need to indicate the feedback time of the transmitting end and the specific psch data transmission resource allocation, nor does it need to indicate other information related to data transmission. The example is only one embodiment provided in this application, and in practical applications, not limited to the specific value 0, one or more fields in the feedback signal SCI _ linear may also be set to other specific values, which is not limited herein.

In the first implementation manner, the receiving end may return a feedback signal SCI _ linear to the transmitting end through a control channel (e.g., PSCCH) at a feedback time.

Second, the feedback signal may be a special MAC layer data frame, which may be called a MAC layer linkalive frame. The payload (payload) of the MAC layer linkalive frame may be a special value. The frame structure of the MAC layer linkalive frame may follow the frame structure of an existing Sidelink Shared Channel (SL-SCH).

For example, as shown in fig. 7, the payload of the MAC layer linkalive frame may be a special value such as the sequence 01010111. The examples are only used for explaining the present application, and in practical applications, the payload of the MAC layer linkalive frame may also be set to other special values, which is not limited herein.

In the second implementation manner, the receiving end may return the MAC layer linkalive frame to the transmitting end through a data channel (e.g., psch) at the feedback time.

In the second implementation manner, in addition to the MAC layer linkalive frame, the receiving end needs to send an SCI signaling to the sending end, where the SCI signaling is used to indicate the sending time of the MAC layer linkalive frame, the resource occupied by the MAC layer linkalive frame in the data channel (e.g., psch), and the transmission policy (e.g., MCS), so that the sending end can correctly receive the feedback signal. This SCI signaling may be referred to herein as a second control signal.

Based on the inventive principle, the D2D link detection method provided by the present application is explained below by two embodiments.

Fig. 8A-8C illustrate a D2D link detection method provided by a first embodiment of the present application. In the embodiments of fig. 8A-8C, the first terminal (i.e., the data transmitting end) notifies the second terminal (i.e., the data receiving end) of the feedback time for returning the feedback signal through the new SCI signaling (i.e., the first control signal) shown in fig. 5. The second terminal sends a feedback signal to the first terminal over a D2D control channel (PSCCH). The feedback signal may be SCI _ linear as shown in fig. 6. The description is developed below.

S101, the first terminal sets the initial time T of the link failure detection timer₀. In the present application, the initial time T₀May be expressed as one or more SC period and one PSCCH period, i.e. T₀SC period + PSCCH, n being a positive integer. Here, one or more SC period may indicate a data transmission time, and one PSCCH period may indicate a transmission time reserved for a feedback signal (e.g., SCI _ linear).

Specifically, the initial time T of the failure detection timer₀May be set by the first terminal or may be set by a network device (e.g., a base station). Initial time T of fault detection timer₀May be positively correlated with the size of the data transfer amount. The larger the data transmission quantity is, the larger the initial time T₀The larger. The smaller the data transmission amount is, the smaller the initial time T₀The smaller. It will be appreciated that in some possible cases, the amount of data transferred is small, and the initial time T is₀May be set to SC period + PSCCH.

S102, the first terminal sends a new SCI signaling (i.e. a first control signal) and a data signal to the second terminal with SC period as a period. Specifically, in each SC period, the first terminal may send the first control signal to the second terminal at a certain time(s) within the PSCCH period according to the resource location of the allocated resource for carrying the first control signal. Specifically, in each SC period, the first terminal may transmit the data signal to the second terminal within the pscch period according to the resource location of the allocated resource for carrying the data signal. Specifically, the first control signal may further carry indication information for indicating a sending time of the data signal. Thus, the second terminal can receive the data signal at the corresponding time according to the indication information.

Specifically, the first control signal may carry a time T of the link failure detection timer, which is used to indicate a feedback time when the second terminal returns to the feedback signal SCI _ linear, and is specifically used to indicate that the second terminal sends the feedback signal SCI _ linear at a SC period next to the last SC period.

As shown in fig. 8A, the time T of the link failure detection timer carried by the first control signal is decreased by one SC period every time one SC period elapses. In the first SC period, the time T carried by the first control signal is equal to the initial time T of the link failure detection timer₀(i.e. n SC period + PSCCH). In the second SC period, the first control signal carries a time T equal to (n-1) × SC period + PSCCH. And so on, in the nth (last) SC period, the time T carried by the first control signal is equal to SC period + PSCCH.

In the application, the first control signal carries, in addition to the time of the link failure detection timer, a timing adjustment amount required by the receiving end to correctly receive data, a resource block occupied by the data signal in the PSSCH, and information such as a Modulation and Coding Scheme (MCS), which is convenient for the second terminal to correctly receive the data signal.

It can be understood that, if a link between the first terminal and the second terminal fails in one SC period, the second terminal cannot receive the data signal sent by the first terminal in the one SC period; otherwise, the second terminal can receive the data signal sent by the first terminal in the one SC period.

In the link detection scenario shown in fig. 8A, the link between the first terminal and the second terminal is normal. As shown in FIG. 8A, the second terminal is at T₀The last SC period in the set receives the data signal sent by the first terminal, and starts feedback, referring to S103. In particular, the second terminal may be at T₀The next SC period (i.e. the feedback time) of the last SC period in (b) sends a feedback signal SCI _ linkalive to the first terminal over the control channel PSCCH, as referred to S104. Thus, the first terminal may receive the feedback signal SCI _ linkalive at the feedback time, so as to determine that the link between the first terminal and the second terminal is normal, as referred to S105.

Unlike the scenario shown in fig. 8A in which the link is normal, fig. 8B and 8C show scenarios in which the link fails. The method comprises the following specific steps:

s106, the second terminal is at the initial time T₀The last SC period in (i.e. n SC period + PSCCH) does not receive the data signal sent by the first terminal, and does not send the feedback signal SCI _ linkalive to the first terminal.

S107, since the second terminal does not transmit the feedback signal SCI _ linkalive to the first terminal. Thus, when the link failure detection timer times out (i.e., T)₀0), the first terminal does not receive the feedback signal SCI _ linkalive transmitted by the second terminal. Finally, if the first terminal is at the feedback time (i.e. T) of the feedback signal₀The next SC period of the last SC period) in the first terminal does not receive the feedback signal SCI _ linkalive sent by the second terminal, the first terminal determines that the link between the first terminal and the second terminal has a failure, that is, enters a failure early warning state. Such a failure may be a transient failure that can quickly recover to a normal state.

It will be appreciated that in one scenario, a link failure may directly result in the second terminal not being able to receive a data signal in the last SC period. In another scenario, a link failure may also cause the second terminal to fail to receive the first control signal in the last SC period, which may result in the second terminal failing to correctly receive the data signal transmitted by the first terminal due to the fact that the timing adjustment required for correctly receiving the data, the resource block occupied by the data signal in the psch, and the Modulation and Coding Scheme (MCS) are not known. Both situations result in the second terminal not sending the feedback signal SCI _ linkalive to the first terminal.

Alternatively, both situations may occur simultaneously when a link fails. Optionally, when a link fails, at least one of the two situations may also occur in one or more SC period preceding the last SC period.

In some optional embodiments, when a link failure is first discovered, the first terminal may first determine that the link enters a failure early warning state, and then determine whether the link fails again through a failure early warning process.

The link early warning procedure can be summarized as follows:

(1) after the link fails and enters a failure early warning state, the first terminal reconfigures the initial time of the link detection timer. The initial time of reconfiguration is denoted T₁，T₁SC period + PSCCH, m being a positive integer. That is, the failure early warning process may last m SC period plus one PSCCH period. Optionally, an initial time T of reconfiguration₁May be less than the initial time T configured for the link detection timer prior to entering the fault warning state₀And the link is convenient to quickly confirm whether the link fails. Then, the first terminal may resend the data signal and the first control signal to the second terminal with the SC period as a period. In each SC period, the retransmitted first control signal carries a link detection timer time T, which is used to indicate a time when the second terminal returns the feedback signal SCI _ linkalive. In particular, in the first SC period, the link detection timer time T is equal to the initial reconfiguration time T₁。

(2) If the first terminal is at the feedback time (i.e. T) of the feedback signal₁Receiving a feedback signal SCI _ linkalive returned by the second terminal in the next SC period) of the last SC period in the group, the first terminal may determine that the link between the first terminal and the second terminal is recovered to be normal, otherwise, the first terminal may finally determine that the link between the first terminal and the second terminal is failed.

The following describes a fault warning process with reference to fig. 8B and 8C, taking an SC period (i.e., m is 1) as an example.

In the link detection scenario shown in fig. 8B, the fault early warning process shown in S108 may specifically include:

1. after the link between the first terminal and the second terminal enters the failure warning state, the first terminal resets the initial time of the link detection timer, which may be referred to as S1081. Wherein the reset initial time is denoted as T₁，T₁SC period + PSCCH. The data is then transmitted, within a single SC period,the first terminal continuously sends a first control signal and a data signal to the second terminal, wherein the first control signal carries the initial time T of the link detection timer₁Reference is made to S1082-S1083.

2. The second terminal is at the initial time T₁The last SC period in (1) receives the data signal and initiates feedback, as referenced by S1084. Specifically, the second terminal may transmit the feedback signal SCI _ linear to the first terminal through the PSCCH of the D2D after the SC period next to the last SC period. Accordingly, the first terminal can be at the feedback time (i.e. T) of the feedback signal₁Next to the last SC period in) and determines that the link is normal, refer to S1086.

(ii) in the link detection scenario shown in fig. 8C, the fault early warning process shown in S109 may specifically include:

1. after the link between the first terminal and the second terminal enters the failure early warning state, the first terminal resets the initial time of the link detection timer, which may refer to S1091. Wherein the reset initial time is denoted as T₁，T₁SC period + PSCCH. Then, in a single SC period, the first terminal continues to send the first control signal and the data signal to the second terminal, where the first control signal carries the initial time T of the link detection timer₁Reference may be made to S1092-S1093.

Here, S1091 in fig. 8C is the same as S1081 in fig. 8B, and S1092 to S1093 in fig. 8C are the same as S1082 to S1083 in fig. 8B.

2. The second terminal is at the initial time T₁The last SC period in (1) does not receive the data signal and does not send the feedback signal SCI _ linear to the first terminal, as referred to S1094. Since the second terminal does not send the feedback signal SCI _ linkalive to the first terminal. Thus, when the link failure detection timer times out (i.e., T)₁0), the first terminal does not receive the feedback signal SCI _ linkalive transmitted by the second terminal. Finally, if the first terminal is at the feedback time (i.e. T) of the feedback signal₁Next SC period of the last SC period in (1)If the feedback signal SCI _ linkalive sent by the second terminal is not received, the first terminal determines that the link between the first terminal and the second terminal is failed, which may be referred to as S1095.

3. The first terminal may report the link failure to a network device (base station).

As can be seen from fig. 8B and 8C, unlike the failure early warning stage S108 in fig. 8B, the failure early warning stage S109 in fig. 8C finally determines that the link fails, and the failure early warning stage S108 in fig. 8B finally determines that the link is recovered to be normal.

In the embodiment of fig. 8A or fig. 8B, the second terminal needs to request a time-frequency resource for sending the feedback signal SCI _ linear from a network device (e.g. a base station). Specifically, the second terminal may send a SidelinkUEInformation signaling to the network device through the uplink control channel PUCCH to request the time-frequency resource. Accordingly, the network device may send a Downlink Control Indication (DCI) through a Downlink Control channel PDCCH to indicate a time-frequency resource for carrying the feedback signal SCI _ link.

In the embodiments of fig. 8A to 8C, the first control signal includes a "link failure detection timer" field, and the value of the field can determine the time when the receiving end sends the feedback signal SCI _ linkalive. Thus, the receiving end does not need to feed back for each data packet, but feeds back at the time specified by the link failure detection timer, and the efficiency of link failure detection can be improved. Alternatively, the first control signal may be implemented by extending the existing SCI signaling, i.e. the first control signal may be a new SCI signaling, and the new SCI signaling includes a "link failure detection timer" field. Alternatively, the feedback signal SCI _ linkalive may follow the format of the new SCI signaling, wherein the "link failure detection timer" field is set to a special value, such as 0. In this way, the newly defined first control signal and feedback signal are less modified from the existing standard and are easier to implement.

Fig. 9A-9C illustrate a D2D link detection method provided by a second embodiment of the present application. In the embodiments of fig. 9A-9C, the first terminal (i.e., the data transmitting end) notifies the second terminal (i.e., the data receiving end) of the feedback time for returning the feedback signal through the new SCI signaling (i.e., the first control signal) shown in fig. 5. The second terminal transmits a feedback signal to the first terminal through a D2D data channel (psch). The feedback signal may be a MAC layer linkalive frame shown in fig. 7. The description is developed below.

S201, the first terminal sets the initial time T of the fault detection timer₀. In the present application, the initial time T₀Can be expressed as one or more SC period and one PSCCH period, i.e. T ═ n × SC period + PSCCH, n is a positive integer.

S202, the first terminal sends a new SCI signaling (i.e. a first control signal) and a data signal to the second terminal with SC period as a period. Specifically, for the implementation of S202, reference may be made to S101 in the embodiment of fig. 8A to 8C, which is not described herein again.

In the link detection scenario shown in fig. 9A, the link between the first terminal and the second terminal is normal. As shown in fig. 9A, the second terminal receives the data signal sent by the first terminal in the last SC period in T0 and starts feedback, which can refer to S203. Specifically, the second terminal may transmit a feedback signal (i.e., a MAC layer linkalive frame) to the first terminal through the data channel psch at an SC period (i.e., a feedback time) next to the last SC period, as referred to S205. In this way, the first terminal may receive the feedback signal (i.e., the MAC layer linkalive frame) at the feedback time, so as to determine that the link between the first terminal and the second terminal is normal, as referred to S206.

Before sending the feedback signal (i.e. the MAC layer linkalive frame) to the first terminal, the second terminal needs to request the network device for the resource carrying the feedback signal or select the resource carrying the feedback signal from the D2D communication resource pool, and notify the first terminal of the resource, so that the first terminal can correctly receive the feedback signal (i.e. the MAC layer linkalive frame). Specifically, the second terminal may send a SidelinkUEInformation signaling to the network device through the uplink control channel PUCCH to request a resource carrying the feedback signal. Accordingly, the network device may transmit a Downlink Control Indication (DCI) through a downlink control channel PDCCH to indicate time-frequency resources for carrying a feedback signal (i.e., a MAC layer linkalive frame).

Here, since the second terminal needs to transmit the feedback signal (i.e., the MAC layer linkalive frame) at the feedback time, the resource carrying the feedback signal (i.e., the MAC layer linkalive frame) may be a time-frequency resource within the SC period next to the last SC period in T0. Specifically, the second terminal may notify the first terminal of the resource carrying the feedback signal (i.e., the MAC layer linkalive frame) through SCI signaling, as referred to S204. The SCI signaling may also carry indication information of the feedback time when the second terminal sends the feedback signal, so that the first terminal may receive the feedback signal sent by the second terminal at the corresponding time according to the indication. Here, the SCI signaling may be new SCI signaling provided herein (as shown in fig. 5), and the SCI signaling may be conventional SCI signaling (e.g., SCI signaling in LTE). If the new SCI signaling is used to carry the indication information of the feedback time, the value of the "link failure detection timer" field may be set to 0 or set to null. Specifically, the second terminal further needs to request the network device for resources carrying SCI signaling.

Unlike the scenario shown in fig. 9A in which the link is normal, fig. 9B and 9C show scenarios in which the link fails. The method comprises the following specific steps:

s206, the second terminal does not receive the data signal sent by the first terminal at the last SC period in the initial time T0 (i.e. n × SC period + PSCCH), and does not send a feedback signal (i.e. MAC layer linkalive frame) to the first terminal.

S207, since the second terminal does not transmit the feedback signal (i.e., the MAC layer linkalive frame) to the first terminal. Therefore, when the link is failedFailure detection timer timeout (i.e., T)₀0), the first terminal does not receive the feedback signal (i.e., the MAC layer linkalive frame) transmitted by the second terminal. Finally, if the first terminal is at the feedback time (i.e. T) of the feedback signal₀The next SC period of the last SC period) in the first terminal does not receive the feedback signal sent by the second terminal, the first terminal determines that the link between the first terminal and the second terminal has a failure, that is, enters a failure early warning state. Such a failure may be a transient failure that can quickly recover to a normal state.

It will be appreciated that in one scenario, a link failure may directly result in the second terminal not being able to receive a data signal in the last SC period. In another scenario, a link failure may also cause the second terminal to fail to receive the first control signal in the last SC period, which may result in the second terminal failing to correctly receive the data signal transmitted by the first terminal due to the fact that the timing adjustment required for correctly receiving the data, the resource block occupied by the data signal in the psch, and the Modulation and Coding Scheme (MCS) are not known. Both of these situations may result in the second terminal not sending a feedback signal (i.e., a MAC layer linkalive frame) to the first terminal.

The link early warning procedure can be summarized as follows:

(1) after the link fails and enters a failure early warning state, the first terminal reconfigures the initial time of the link detection timer. The initial time of reconfiguration is denoted T₁，T₁SC period + PSCCH, m being a positive integer. That is, the failure warning process may last m SC period plus one PSCCHAnd (4) period. Optionally, an initial time T of reconfiguration₁May be less than the initial time T configured for the link detection timer prior to entering the fault warning state₀And the link is convenient to quickly confirm whether the link fails. Then, the first terminal may resend the data signal and the first control signal to the second terminal with the SC period as a period. In each SC period, the retransmitted first control signal carries a link detection timer time T, which is used to indicate a time when the second terminal returns a feedback signal (i.e., a MAC layer linkalive frame). In particular, in the first SC period, the link detection timer time T is equal to the initial reconfiguration time T₁。

(2) If the first terminal is at the feedback time (i.e. T) of the feedback signal₁Receiving a feedback signal (i.e., a MAC layer linkalive frame) returned by the second terminal in the next SC period) of the last SC period in the second SC period), the first terminal may determine that the link between the first terminal and the second terminal is recovered to be normal, otherwise, the first terminal may finally determine that the link between the first terminal and the second terminal is failed.

The following describes a fault warning process with reference to fig. 9B and 9C, taking an SC period (i.e., m is 1) as an example.

In the link detection scenario shown in fig. 9B, the fault early warning process shown in S208 may specifically include:

1. after the link between the first terminal and the second terminal enters the failure early warning state, the first terminal resets the initial time of the link detection timer, referring to S2081. Wherein the reset initial time is denoted as T₁，T₁SC period + PSCCH. Then, in a single SC period, the first terminal continues to send the first control signal and the data signal to the second terminal, where the first control signal carries the initial time T of the link detection timer₁Reference may be made to S2082-S2083.

2. The second terminal is at the initial time T₁The last SC period in (1) receives the data signal and starts feedback, as referred to S2084. Specifically, the second terminal may be at the last SC periodD, the next SC period transmits a feedback signal (i.e., a MAC layer linkalive frame) to the first terminal through the data channel pscch of D2D. Accordingly, the first terminal can be at the feedback time (i.e. T) of the feedback signal₁Next to the last SC period in (S) and receiving the feedback signal (i.e., the MAC layer linkalive frame), and determining that the link is normal, refer to S2086.

(ii) in the link detection scenario shown in fig. 9C, the fault early warning process shown in S209 may specifically include:

1. after the link between the first terminal and the second terminal enters the failure warning state, the first terminal resets the initial time of the link detection timer, as referred to S2091. Wherein the reset initial time is denoted as T₁，T₁SC period + PSCCH. Then, in a single SC period, the first terminal continues to send the first control signal and the data signal to the second terminal, where the first control signal carries the initial time T of the link detection timer₁Reference is made to S2092-S2093.

Here, S2091 in fig. 9C is the same as S2081 in fig. 9B, and S2092 to S2093 in fig. 9C are the same as S2082 to S2083 in fig. 9B.

2. The second terminal is at the initial time T₁The last SC period in (1) does not receive the data signal and does not send a feedback signal (i.e., a MAC layer linear frame) to the first terminal, refer to S2094. Since the second terminal does not transmit a feedback signal (i.e., a MAC layer linkalive frame) to the first terminal. Thus, when the link failure detection timer times out (i.e., T)₁0), the first terminal does not receive the feedback signal (i.e., the MAC layer linkalive frame) transmitted by the second terminal. Finally, if the first terminal is at the feedback time (i.e. T) of the feedback signal₁Next to the last SC period in the series), no feedback signal (i.e., MAC layer linear frame) sent by the second terminal is received, and the first terminal determines that the link between the first terminal and the second terminal is failed, as shown in S2095.

As can be seen from fig. 9B and 9C, unlike the fault pre-warning stage S208 in fig. 9B, the fault pre-warning stage S209 in fig. 9C finally determines that the link is faulty, and the fault pre-warning stage S208 in fig. 9B finally determines that the link is recovered to be normal.

In the embodiments of fig. 9A to 9C, the first control signal includes a field of a "link failure detection timer", where a value of the field may determine a time when the receiving end sends a feedback signal MAC layer linkalive frame, and indication information of the time may be carried in an SCI signaling sent by the second terminal to the first terminal, so as to notify the first terminal to receive the feedback signal sent by the second terminal at a corresponding time. Thus, the receiving end does not need to feed back for each data packet, but feeds back at the time specified by the link failure detection timer, and the efficiency of link failure detection can be improved. Alternatively, the first control signal may be implemented by extending the existing SCI signaling, i.e. the first control signal may be a new SCI signaling, and the new SCI signaling includes a "link failure detection timer" field. Alternatively, the payload of the feedback signal MAC layer linkalive frame may be a special value, such as the sequence 01010111. In this way, the newly defined first control signal and feedback signal are less modified from the existing standard and are easier to implement.

Referring to fig. 10, fig. 10 shows a wireless communication system and a communication apparatus provided in the present application. The wireless communication system 10 includes: communication device 400 and communication device 500. A D2D communication connection is established between communication device 400 and communication device 500. The communication device 400 and the communication device 500 may be a first terminal and a second terminal in the embodiments of fig. 8A to 8C or fig. 9A to 9C, respectively. The communication device 400 and the communication device 500 may be the terminal 200 in the embodiment of fig. 3. The wireless communication system 10 may be the wireless communication system 100 described in fig. 2, and the communication devices 400 and 500 may be the terminals 103 in the wireless communication system 100. Described separately below.

As shown in fig. 10, the communication device 400 may include: a processing unit 401 and a communication unit 403.

The communication unit 403 can be used for sending a data signal and a first control signal to the communication device 500. The first control signal carries indication information of feedback time, and is used to indicate the communication apparatus 500 to send a feedback signal to the communication apparatus 400 at the feedback time. The feedback signal is transmitted by the communication apparatus 500 to the communication apparatus 400 after receiving the data signal. The processing unit 401 may be configured to determine that the D2D link between the communication device 400 and the communication device 500 is normal if the communication unit 403 receives the feedback signal sent by the communication device 500 at the feedback time.

Here, the communication unit 403 may be specifically configured to send the data signal and the first control signal to the communication device 500 in a cycle of a first time interval. Wherein the first time interval comprises a second time interval and a third time interval, the D2D communication resource (which may be referred to as the first communication resource) on the second time interval is used for carrying the first control signal, and the D2D communication resource on the third time interval is used for carrying the data signal. The D2D communication resources are resources allocated by the network device for D2D communication between the communication device 400 and the communication device 500.

Specifically, the first time interval may be a secondary link control period SC period, the second time interval may be a secondary link physical control channel period (i.e., PSCCH period), and the third time interval may be a secondary link physical shared channel period (i.e., PSCCH period).

In some embodiments, the feedback time may be indicated by a time of a timer, i.e. the indication information of the feedback time may be time information of the timer. Here, the timer may be referred to as a failure detection timer. Specifically, the time of the failure detection timer may be expressed as at least one SC period plus one PSCCH period, i.e., n × SC period + PSCCH, where n is a positive integer. The feedback time indicated by the time of the failure detection timer is the SC Period next to the last SC Period in n SC periods.

In this application, the first control signal may be a new PSCCH signaling. Specifically, SCI signaling may be extended to implement the new PSCCH signaling, that is, the new PSCCH signaling may be new SCI signaling. The new SCI signaling includes a new field, e.g., a link failure detection timer field, for indicating the time of the failure detection timer, i.e., for indicating the feedback time. In this application, this new field may be referred to as a first field.

In some optional embodiments, when a link failure is first discovered, the processing unit 401 may first determine that the link enters a failure early warning state, and then determine whether the link fails again through a failure early warning process. In the link early warning process, the communication device 400 includes the following functional units:

the communication unit 403 may also be configured to retransmit the data signal and the first control signal to the communication device 500 if the feedback signal transmitted by the communication device 500 is not received at the feedback time. Wherein the retransmitted first control signal carries a new feedback time.

The processing unit 401 may be further configured to determine that the D2D link between the communication device 400 and the communication device 500 is restored to normal if the communication unit 403 receives the feedback signal sent by the communication device 500 at the new feedback time. Otherwise, a D2D link failure between communication device 400 and communication device 500 is determined.

In some alternative embodiments, the feedback signal may be transmitted by communications apparatus 500 over the secondary link control channel PSCCH. Accordingly, communication unit 403 may receive the feedback signal transmitted by communication apparatus 500 over the secondary link control channel PSCCH.

In some alternative embodiments, the feedback signal may be transmitted by communications apparatus 500 over a secondary link data channel psch. Accordingly, communication unit 403 may receive the feedback signal transmitted by communication apparatus 500 through the secondary link data channel psch. Additionally, to inform the resource location occupied by the feedback signal in the secondary link data channel psch, communications apparatus 500 also transmits a second control signal, e.g., SCI signaling, to communications apparatus 400 indicating the resource location occupied by the feedback signal in the secondary link data channel psch. Accordingly, the communication unit 403 may be further configured to receive a second control signal sent by the communication apparatus 500, where the second control signal is used to indicate a resource location occupied by the feedback signal in the secondary link data channel psch.

It is understood that specific implementations of each functional unit included in the communication apparatus 400 may also refer to the embodiments in fig. 8A to 8C or fig. 9A to 9C, and are not described herein again.

As shown in fig. 10, the communication device 500 may include: a communication unit 501 and a processing unit 503.

Wherein, in the uplink transmission process:

a communication unit 501, configured to receive a data signal and a first control signal sent by the communication apparatus 400;

the processing unit 503 is configured to, if the communication unit 501 receives the data signal and the first control signal sent by the communication apparatus 400, send a feedback signal to the communication apparatus 400 at the feedback time according to the indication information of the feedback time carried in the first control signal, otherwise, not send the feedback signal. Wherein the indication information of the feedback time is used to instruct the communication unit 501 to transmit the feedback signal to the communication device 400 at the feedback time.

Here, the communication unit 501 may be specifically configured to receive the data signal and the first control signal sent by the communication device 400 at a first time interval as a cycle. Wherein the first time interval comprises a second time interval and a third time interval, the D2D communication resource (which may be referred to as the first communication resource) on the second time interval is used for carrying the first control signal, and the D2D communication resource on the third time interval is used for carrying the data signal. The D2D communication resources are resources allocated by the network device for D2D communication between the communication device 400 and the communication device 500.

In some optional embodiments, when a link failure is first discovered, the communication apparatus 400 may first determine that the link enters a failure warning state, and then determine again whether the link has failed through a failure warning process. In the link early warning process, the communication device 500 includes the following functional units:

the communication unit 501 is further configured to send the feedback signal to the communication apparatus 400 at a new feedback time according to the new indication information of the feedback time carried in the retransmitted first control signal if the data signal and the first control signal retransmitted by the communication apparatus 400 are received, and otherwise, not send the feedback signal. Wherein the indication information of the new feedback time is used to instruct the communication apparatus 500 to transmit the feedback signal to the communication apparatus 400 at the new feedback time.

In some alternative embodiments, communication unit 501 may be specifically configured to transmit the feedback signal to communication apparatus 400 over the secondary link control channel PSCCH.

In some alternative embodiments, communication unit 501 may be specifically configured to send the feedback signal to communication apparatus 400 via a secondary link data channel psch. In addition, in order to inform the resource location occupied by the feedback signal in the secondary link data channel psch, the communication unit 501 is further configured to send a second control signal, e.g. SCI signaling, to the communication device 400 for indicating the resource location occupied by the feedback signal in the secondary link data channel psch.

It is understood that specific implementations of the functional units included in the communication apparatus 500 may also refer to the embodiments in fig. 8A to 8C or fig. 9A to 9C, and are not described herein again.

In summary, the present application defines a first control signal (new SCI signaling), where the first control signal includes a field for indicating the time of the link failure detection timer, and the value of the field can determine the time for the receiving end to send the feedback signal SCI _ linkalive. Thus, the receiving end does not need to feed back for each data packet, but feeds back at the time specified by the link failure detection timer, and the efficiency of link failure detection can be improved. Moreover, the first control signal is realized by expanding the existing SCI signaling, so that the modification of the existing D2D communication standard is reduced as much as possible, and the implementation is easier.

One of ordinary skill in the art will appreciate that all or part of the processes in the methods of the above embodiments may be implemented by hardware related to instructions of a computer program, which may be stored in a computer-readable storage medium, and when executed, may include the processes of the above method embodiments. And the aforementioned storage medium includes: various media capable of storing program codes, such as ROM or RAM, magnetic or optical disks, etc.

Claims

1. A D2D link detection method, comprising:

the first terminal sends a data signal and a first control signal to the second terminal; the first control signal carries indication information of feedback time, and is used for indicating the second terminal to send a feedback signal to the first terminal at the feedback time; the feedback signal is sent to the first terminal by the second terminal after receiving the data signal; a D2D communication connection is established between the first terminal and the second terminal, the first terminal and the second terminal are in the coverage area of the same network device, and D2D communication resources for carrying the data signal and the first control signal are allocated by the network device;

and if the first terminal receives the feedback signal sent by the second terminal at the feedback time, judging that the D2D link between the first terminal and the second terminal is normal.

2. The method of claim 1, wherein the first terminal sending a data signal and a first control signal to a second terminal, specifically comprises:

the first terminal sends the data signal and the first control signal to the second terminal by taking a first time interval as a period; wherein the first time interval comprises a second time interval and a third time interval, the first communication resource on the second time interval is used for carrying the first control signal, and the first communication resource on the third time interval is used for carrying the data signal; the first communication resource is a resource allocated by a network device for D2D communication between the first terminal and the second terminal.

3. The method according to claim 2, wherein the information indicative of the feedback time is specifically time information of a timer; the time of the timer is equal to at least one first time interval plus one second time interval, and the feedback time is the next first time interval of the last first time interval in the time of the timer.

4. The method of any of claims 2-3, wherein the first time interval is a secondary link control period, the second time interval is a secondary link physical control channel period, and the third time interval is a secondary link physical shared channel period.

5. The method of any one of claims 1-3, further comprising: if the first terminal does not receive the feedback signal sent by the second terminal in the feedback time, then:

retransmitting the data signal and the first control signal to a second terminal; wherein the retransmitted first control signal carries a new feedback time;

if the first terminal receives the feedback signal sent by the second terminal at the new feedback time, determining that a D2D link between the first terminal and the second terminal returns to normal; otherwise, determining that the D2D link between the first terminal and the second terminal fails.

6. The method of claim 4, further comprising: if the first terminal does not receive the feedback signal sent by the second terminal in the feedback time, then:

7. The method of any of claims 1-3, wherein the feedback signal is sent by the second terminal over a secondary link control channel.

8. The method of claim 4, wherein the feedback signal is transmitted by the second terminal over a sidelink control channel.

9. The method of claim 5, wherein the feedback signal is transmitted by the second terminal over a sidelink control channel.

10. The method of any of claims 1-3, wherein the feedback signal is transmitted by the second terminal over a sidelink data channel;

the method further comprises the following steps: and receiving a second control signal sent by the second terminal, where the second control signal is used to indicate a resource location occupied by the feedback signal in the sidelink data channel.

11. The method of claim 4, wherein the feedback signal is transmitted by the second terminal over a sidelink data channel;

12. The method of claim 5, wherein the feedback signal is transmitted by the second terminal over a sidelink data channel;

13. The method of any of claims 1-3, wherein the first control signal is a SCI control signal, the SCI control signal including a first field to indicate the feedback time.

14. The method of claim 4, wherein the first control signal is a SCI control signal, the SCI control signal comprising a first field indicating the feedback time.

15. The method of claim 5, wherein the first control signal is a SCI control signal, the SCI control signal comprising a first field indicating the feedback time.

16. The method of claim 6, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

17. The method of claim 7, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

18. The method of claim 8, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

19. The method of claim 9, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

20. The method of claim 10, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

21. A D2D link detection method, comprising:

if a second terminal receives a data signal and a first control signal sent by a first terminal, the second terminal sends a feedback signal to the first terminal at the feedback time according to indication information of the feedback time carried in the first control signal; otherwise, the second terminal does not send the feedback signal; the indication information of the feedback time is used for indicating the second terminal to send the feedback signal to the first terminal at the feedback time; D2D communication connection is established between the first terminal and the second terminal, the first terminal and the second terminal are in the coverage area of the same network device, and D2D communication resources for carrying the data signals and the first control signals are allocated by the network device.

22. The method of claim 21, wherein the receiving, by the second terminal, the data signal and the first control signal sent by the first terminal comprises:

the second terminal receives the data signal and the first control signal sent by the first terminal by taking a first time interval as a period; wherein the first time interval comprises a second time interval and a third time interval, the first communication resource on the second time interval is used for carrying the first control signal, and the first communication resource on the third time interval is used for carrying the data signal; the first communication resource is a resource allocated by a network device for D2D communication between the first terminal and the second terminal.

23. The method according to claim 22, wherein the information indicative of the feedback time is specifically time information of a timer; the time of the timer is equal to at least one first time interval plus one second time interval, and the feedback time is the next first time interval of the last first time interval in the time of the timer.

24. The method of any one of claims 22-23, wherein the first time interval is a secondary link control period, the second time interval is a secondary link physical control channel period, and the third time interval is a secondary link physical shared channel period.

25. The method of any one of claims 21-23, further comprising: if the second terminal does not receive the data signal, then:

if the second terminal receives the data signal and the first control signal retransmitted by the first terminal, the second terminal sends the feedback signal to the first terminal at a new feedback time according to the indication information of the new feedback time carried in the retransmitted first control signal; otherwise, the second terminal does not send the feedback signal; and the indication information of the new feedback time is used for indicating the second terminal to send the feedback signal to the first terminal at the new feedback time.

26. The method of claim 24, further comprising: if the second terminal does not receive the data signal, then:

27. The method according to any one of claims 21 to 23, wherein the sending, by the second terminal, the feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal specifically includes: and the second terminal sends a feedback signal to the first terminal through a secondary link control channel at the feedback time according to the indication information of the feedback time carried in the first control signal.

28. The method of claim 24, wherein the second terminal sends the feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal, and specifically includes: and the second terminal sends a feedback signal to the first terminal through a secondary link control channel at the feedback time according to the indication information of the feedback time carried in the first control signal.

29. The method of claim 25, wherein the second terminal sends the feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal, and specifically includes: and the second terminal sends a feedback signal to the first terminal through a secondary link control channel at the feedback time according to the indication information of the feedback time carried in the first control signal.

30. The method according to any one of claims 21 to 23, wherein the sending, by the second terminal, the feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal specifically includes: the second terminal sends a feedback signal to the first terminal through a sidelink data channel at the feedback time according to the indication information of the feedback time carried in the first control signal;

the method further comprises the following steps: and the second terminal sends a second control signal to the first terminal, wherein the second control signal is used for indicating the resource position occupied by the feedback signal in the sidelink data channel.

31. The method of claim 24, wherein the second terminal sends the feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal, and specifically includes: the second terminal sends a feedback signal to the first terminal through a sidelink data channel at the feedback time according to the indication information of the feedback time carried in the first control signal;

32. The method of claim 25, wherein the second terminal sends the feedback signal to the first terminal at the feedback time according to the indication information of the feedback time carried in the first control signal, and specifically includes: the second terminal sends a feedback signal to the first terminal through a sidelink data channel at the feedback time according to the indication information of the feedback time carried in the first control signal;

33. The method of any of claims 21-23, wherein the first control signal is an SCI control signal, the SCI control signal including a first field to indicate the feedback time.

34. The method of claim 24, wherein the first control signal is an SCI control signal, the SCI control signal including a first field indicating the feedback time.

35. The method of claim 25, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

36. The method of claim 26, wherein the first control signal is an SCI control signal, the SCI control signal including a first field indicating the feedback time.

37. The method of claim 27, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

38. The method of claim 28, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

39. The method of claim 29, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

40. The method of claim 30, wherein the first control signal is a SCI control signal, the SCI control signal including a first field indicating the feedback time.

41. A communications apparatus, the communications apparatus being a first terminal, comprising:

the communication unit is used for sending a data signal and a first control signal to the second terminal; the first control signal carries indication information of feedback time, and is used for indicating the second terminal to send a feedback signal to the first terminal at the feedback time; the feedback signal is sent to the first terminal by the second terminal after receiving the data signal; a D2D communication connection is established between the first terminal and the second terminal, the first terminal and the second terminal are in the coverage area of the same network device, and D2D communication resources for carrying the data signal and the first control signal are allocated by the network device;

and the processing unit is used for judging that the D2D link between the first terminal and the second terminal is normal if the communication unit receives the feedback signal sent by the second terminal at the feedback time.

42. The apparatus of claim 41, wherein the communication unit is specifically configured to send the data signal and the first control signal to the second terminal in a cycle of a first time interval; wherein the first time interval comprises a second time interval and a third time interval, the first communication resource on the second time interval is used for carrying the first control signal, and the first communication resource on the third time interval is used for carrying the data signal; the first communication resource is a resource allocated by a network device for D2D communication between the first terminal and the second terminal.

43. The apparatus according to claim 42, wherein the information indicative of the feedback time is specifically time information of a timer; the time of the timer is equal to at least one first time interval plus one second time interval, and the feedback time is the next first time interval of the last first time interval in the time of the timer.

44. The apparatus of claim 42, wherein the first time interval is a secondary link control period, the second time interval is a secondary link physical control channel period, and the third time interval is a secondary link physical shared channel period.

45. The apparatus of claim 43, wherein the first time interval is a secondary link control period, the second time interval is a secondary link physical control channel period, and the third time interval is a secondary link physical shared channel period.

46. The apparatus according to any of claims 42-45, wherein the communication unit is further configured to retransmit the data signal and the first control signal to a second terminal if the feedback signal transmitted by the second terminal is not received at the feedback time; wherein the retransmitted first control signal carries a new feedback time;

the processing unit is further configured to determine that the D2D link between the first terminal and the second terminal returns to normal if the communication unit receives the feedback signal sent by the second terminal at the new feedback time; otherwise, determining that the D2D link between the first terminal and the second terminal fails.

47. The apparatus of any of claims 42-45, wherein the feedback signal is sent by the second terminal over a secondary link control channel.

48. The apparatus of claim 46, wherein the feedback signal is sent by the second terminal over a sidelink control channel.

49. The apparatus of any of claims 42-45, wherein the feedback signal is sent by the second terminal over a sidelink data channel;

the communication unit is further configured to receive a second control signal sent by the second terminal, where the second control signal is used to indicate a resource location occupied by the feedback signal in the sidelink data channel.

50. The apparatus of claim 46, wherein the feedback signal is transmitted by the second terminal over a sidelink data channel;

51. The apparatus of any of claims 42-45, wherein the first control signal is an SCI control signal that includes a first field to indicate the feedback time.

52. The apparatus of claim 46, wherein the first control signal is a SCI control signal comprising a first field indicating the feedback time.

53. The apparatus of claim 47, wherein the first control signal is a SCI control signal comprising a first field indicating the feedback time.

54. A communication device, the communication device being a second terminal, comprising: a communication unit and a processing unit, wherein:

the communication unit is used for receiving a data signal and a first control signal sent by a first terminal;

the processing unit is configured to send a feedback signal to the first terminal at the feedback time according to indication information of the feedback time carried in the first control signal if the communication unit receives a data signal and a first control signal sent by the first terminal; otherwise, not sending the feedback signal; the indication information of the feedback time is used for indicating the communication unit to send the feedback signal to the first terminal at the feedback time; D2D communication connection is established between the first terminal and the second terminal, the first terminal and the second terminal are in the coverage area of the same network device, and D2D communication resources for carrying the data signals and the first control signals are allocated by the network device.

55. The apparatus of claim 54, wherein the communication unit is specifically configured to receive the data signal and the first control signal sent by the first terminal in a cycle of a first time interval; wherein the first time interval comprises a second time interval and a third time interval, the first communication resource on the second time interval is used for carrying the first control signal, and the first communication resource on the third time interval is used for carrying the data signal; the first communication resource is a resource allocated by a network device for D2D communication between the first terminal and the second terminal.

56. The apparatus according to claim 55, wherein the information indicative of the feedback time is specifically time information of a timer; the time of the timer is equal to at least one first time interval plus one second time interval, and the feedback time is the next first time interval of the last first time interval in the time of the timer.

57. The apparatus of claim 55, wherein the first time interval is a secondary link control period, the second time interval is a secondary link physical control channel period, and the third time interval is a secondary link physical shared channel period.

58. The apparatus of claim 56, wherein the first time interval is a secondary link control period, the second time interval is a secondary link physical control channel period, and the third time interval is a secondary link physical shared channel period.

59. The apparatus according to any of claims 55-58, wherein the communication unit is further configured to, if the communication unit receives the data signal and the first control signal retransmitted by the first terminal, send the feedback signal to the first terminal at a new feedback time according to indication information of the new feedback time carried in the retransmitted first control signal; otherwise, not sending the feedback signal; and the indication information of the new feedback time is used for indicating the second terminal to send the feedback signal to the first terminal at the new feedback time.

60. The apparatus according to any of claims 55-58, wherein the communication unit is specifically configured to send a feedback signal to the first terminal through a secondary link control channel at the feedback time according to the indication information of the feedback time carried in the first control signal.

61. The apparatus of claim 60, wherein the communication unit is specifically configured to send a feedback signal to the first terminal through a sidelink control channel at the feedback time according to indication information of the feedback time carried in the first control signal.

62. The apparatus according to any of claims 55-58, wherein the communication unit is specifically configured to send a feedback signal to the first terminal through a sidelink data channel at the feedback time according to the indication information of the feedback time carried in the first control signal;

the communication unit is further configured to send a second control signal to the first terminal, where the second control signal is used to indicate a resource location occupied by the feedback signal in the sidelink data channel.

63. The apparatus according to claim 59, wherein the communication unit is specifically configured to send a feedback signal to the first terminal through a sidelink data channel at the feedback time according to indication information of the feedback time carried in the first control signal;

64. The apparatus of any of claims 55-58, wherein the first control signal is a SCI control signal that includes a first field to indicate the feedback time.

65. The apparatus of claim 59, wherein the first control signal is a SCI control signal comprising a first field for indicating the feedback time.

66. The apparatus of claim 60, wherein the first control signal is a SCI control signal comprising a first field for indicating the feedback time.

67. The apparatus of claim 61, wherein the first control signal is a SCI control signal comprising a first field for indicating the feedback time.

68. The apparatus of claim 62, wherein the first control signal is an SCI control signal comprising a first field indicating the feedback time.

69. A communication system, comprising: a first terminal and a second terminal, wherein:

the first terminal is the communication device of any one of claims 41-53;

the second terminal is the communication device of any one of claims 54-68.