WO2020253658A1 - 通信方法及装置 - Google Patents

通信方法及装置 Download PDF

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Publication number
WO2020253658A1
WO2020253658A1 PCT/CN2020/096203 CN2020096203W WO2020253658A1 WO 2020253658 A1 WO2020253658 A1 WO 2020253658A1 CN 2020096203 W CN2020096203 W CN 2020096203W WO 2020253658 A1 WO2020253658 A1 WO 2020253658A1
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Prior art keywords
terminal
group
layer
reachable
group member
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PCT/CN2020/096203
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English (en)
French (fr)
Inventor
应江威
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华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to MX2021015681A priority Critical patent/MX2021015681A/es
Priority to BR112021025198A priority patent/BR112021025198A2/pt
Priority to EP20826830.0A priority patent/EP3975591B1/en
Publication of WO2020253658A1 publication Critical patent/WO2020253658A1/zh
Priority to US17/552,697 priority patent/US20220109586A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/02—Details
    • H04L12/16—Arrangements for providing special services to substations
    • H04L12/18—Arrangements for providing special services to substations for broadcast or conference, e.g. multicast
    • H04L12/1863—Arrangements for providing special services to substations for broadcast or conference, e.g. multicast comprising mechanisms for improved reliability, e.g. status reports
    • H04L12/1868—Measures taken after transmission, e.g. acknowledgments
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/06—Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1812—Hybrid protocols; Hybrid automatic repeat request [HARQ]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/02—Details
    • H04L12/16—Arrangements for providing special services to substations
    • H04L12/18—Arrangements for providing special services to substations for broadcast or conference, e.g. multicast
    • H04L12/1881—Arrangements for providing special services to substations for broadcast or conference, e.g. multicast with schedule organisation, e.g. priority, sequence management
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/30—Services specially adapted for particular environments, situations or purposes
    • H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/30—Services specially adapted for particular environments, situations or purposes
    • H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
    • H04W4/46—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P] for vehicle-to-vehicle communication [V2V]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/80—Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/11—Allocation or use of connection identifiers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H04W76/14—Direct-mode setup
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1829—Arrangements specially adapted for the receiver end
    • H04L1/1861—Physical mapping arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L2001/0092—Error control systems characterised by the topology of the transmission link
    • H04L2001/0093—Point-to-multipoint
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
    • H04L5/0055—Physical resource allocation for ACK/NACK

Definitions

  • This application relates to the field of communication technology, and in particular to communication methods and devices.
  • V2X vehicle to everything
  • the vehicle to everything (V2X) technology is the key technology of the future intelligent transportation system. It enables communication between vehicles and base stations, enabling vehicles to obtain real-time road conditions, road information, pedestrian information and other traffic information, thereby effectively improving the safety of car driving, reducing congestion, improving traffic efficiency, and providing on-board vehicles. Entertainment information, etc.
  • the V2X network can also use the multicast mode to transmit data.
  • the sender sends multicast information to the group members, and group members located around the sender send an acknowledgement (acknowledgement, ACK) to the sender after receiving the multicast information sent by the sender.
  • ACK acknowledgement
  • the sender determines whether all group members located around the sender successfully receive the multicast information according to the received ACK message. If the sender determines that at least one member of the surrounding group members has not successfully received the multicast information, the sender can resend the multicast information to implement the hybrid automatic repeat request (HARQ) of the multicast mechanism.
  • HARQ hybrid automatic repeat request
  • the AS of the terminal cannot determine whether all group members located around the terminal successfully receive the multicast information. As a result, the AS of the terminal cannot normally execute the HARQ mechanism of multicast.
  • the present application provides a communication method and device for enabling the AS of the terminal to determine the specific number of group members located around the terminal in the group, so that the AS of the terminal can normally execute the HARQ mechanism of multicast.
  • a communication method including: a V2X layer of a first terminal sends a first message, the first message includes an identifier of a group, and the first terminal corresponds to a first group member in the group;
  • the V2X layer receives the response message of the first message;
  • the V2X layer of the first terminal determines the number of reachable group members in the group according to the response message;
  • the V2X layer of the first terminal sends the reachable group member's information to the AS of the first terminal Number.
  • the V2X layer of the first terminal sends a first message to trigger the terminal corresponding to other group members in the group to feed back a response message, so that the V2X layer of the first terminal can find the first message in the group according to the response message.
  • the group members around the group members to determine the number of group members that can be reached.
  • the V2X layer of the first terminal sends the number of reachable group members to the AS of the first terminal, so that the AS of the first terminal can perceive the specific number of group members around the first terminal.
  • the AS of the first terminal can determine whether all the group members located around the first terminal succeeded according to whether the number of ACK messages received is equal to the specific number of group members around the first terminal.
  • the multicast information is received, thereby ensuring that the AS of the first terminal normally executes the HARQ mechanism of the multicast.
  • the method further includes: the V2X layer of the first terminal obtains the number of the first group member, and sends the number of the first group member to the AS of the first terminal.
  • the number of the first group member is used to determine the feedback resource corresponding to the first group member.
  • the first group member is one of the reachable group members in the group.
  • the V2X layer of the first terminal obtains the number of the first group member, including: the V2X layer of the first terminal determines the number of the first group member according to the size of the application layer identifier of the reachable group member; or, the V2X layer of the first terminal Determine the number of the first group member according to the size of the layer 2 identifier of the reachable group member; or, the V2X layer of the first terminal allocates the number of the first group member.
  • the number of the first group member is the layer 2 ID of the first group member or the layer 1 ID of the first group member.
  • the method includes: the AS of the first terminal receives the multicast message; the AS of the first terminal determines the feedback resource according to the number of the first group member; the AS of the first terminal sends the multicast according to the feedback resource ACK/Negative acknowledgement (NACK) message of the message.
  • NACK feedback resource ACK/Negative acknowledgement
  • the AS of the first terminal determines the corresponding feedback resource according to the number of the first group member, thereby ensuring that the AS of the first terminal can normally feed back ACK/NACK messages to the multicast sending end.
  • the multicast sender does not need to configure corresponding feedback resources for each of the reachable members one by one, which is beneficial to save signaling overhead and also reduces the complexity of implementing the multicast process.
  • the response message of the first message includes the identifier of the group and the identifier of the second group member in the group, and the second group member is one of the reachable members in the group.
  • the method further includes: the V2X layer of the first terminal sends a second message to the second terminal corresponding to the second group member, the second message carrying the number of reachable group members or reachable group members At least one of the logos.
  • the second message includes any of the following: the number of the reachable group member; or, the number of the second group member; or, the reachable group members except the first group member Number.
  • the second message also includes an identification of the group.
  • a communication method including: a V2X layer of a second terminal receives a first message from a first terminal, the first message includes an identifier of a group, and the first terminal corresponds to a first group member in the group, The second terminal corresponds to the second group member in the group; the V2X layer of the second terminal sends a response message of the first message to the first terminal; the V2X layer of the second terminal receives the second message from the first terminal; the second terminal According to the second message, the V2X layer obtains the number of reachable group members in the group; the V2X layer of the second terminal sends the number of reachable group members to the AS of the second terminal.
  • the V2X layer of the second terminal receives the first message from the first terminal, and sends a response message of the first message to the first terminal, so that the first terminal can find the second group corresponding to the second terminal
  • the member is a peripheral group member of the first group member corresponding to the first terminal.
  • the V2X layer of the second terminal receives the second message from the first terminal and obtains the number of reachable group members.
  • the V2X layer of the second terminal sends the number of reachable group members to the AS of the second terminal, so that the AS of the second terminal can perceive the specific number of group members around the second terminal.
  • the AS of the second terminal can determine whether all the group members located around the second terminal succeeded according to whether the number of ACK messages received is equal to the specific number of group members around the second terminal.
  • the multicast information is received, thereby ensuring that the AS of the second terminal normally executes the HARQ mechanism of the multicast.
  • the response message includes the identity of the group and the identity of the second group member.
  • the second message carries at least one of the number of reachable group members or the identification of reachable group members.
  • the second message includes any of the following: the number of the reachable group member; or, the number of the second group member; or, the reachable group members except the first group member Number.
  • the method when the second message includes the number of the second group member, the method further includes: the V2X layer of the second terminal obtains the number of the second group member according to the second message; second The V2X layer of the terminal sends the number of the second group member to the AS of the second terminal.
  • the method further includes: the AS of the second terminal receives the multicast message; the AS of the second terminal determines the feedback resource according to the number of the second group member; the AS of the second terminal sends the group according to the feedback resource ACK/NACK message of broadcast message.
  • the AS of the second terminal determines the corresponding feedback resource according to the number of the second group member, thereby ensuring that the AS of the second terminal can normally feed back ACK/NACK messages to the multicast sender.
  • the multicast sender does not need to configure corresponding feedback resources for each of the reachable members one by one, which is beneficial to save signaling overhead and also reduces the complexity of implementing the multicast process.
  • the second message includes the identity of the group.
  • a communication method including: the application layer of the terminal sends the application layer identifier of the reachable group member in the group to the V2X layer of the terminal, and the terminal corresponds to the third group member in the group; the V2X layer of the terminal is based on The application layer identifier of the reachable group member determines the number of reachable group members; the V2X layer of the terminal sends the number of reachable group members to the AS of the terminal.
  • the AS of the terminal can learn the number of reachable group members, and thus perceive the specific number of group members around the terminal. In this way, the AS of the terminal can determine whether all group members located around the terminal have successfully received multicast information based on whether the number of received ACK messages is equal to the specific number of group members around the terminal. This ensures that the AS of the terminal normally executes the HARQ mechanism of multicast.
  • the V2X layer of the terminal determines the number of reachable group members based on the application layer identifier of the reachable group member, including: the V2X layer of the terminal generates/distributes the available group members according to the application layer identifier of the reachable group member Up to the group member's layer 2 identification; the V2X layer of the terminal determines the number of reachable group members according to the layer 2 identification of the reachable group member.
  • the method further includes: the V2X layer of the terminal obtains the number of the third group member; and the V2X layer of the terminal sends the number of the third group member to the AS of the terminal. Among them, the number of the third group member is used to determine the feedback resources of the third group member.
  • the third group member is one of the reachable group members in the group; the V2X layer of the terminal obtains the number of the third group member, including: the V2X layer of the terminal is based on the application layer of the reachable group member
  • the size of the identifier determines the number of the third group member; or, the V2X layer of the terminal determines the number of the third group member according to the size of the layer 2 identifier of the reachable group member; or, the V2X layer of the terminal determines the number of the third group member according to the first list. Determine the position of the third group member and determine the number of the third group member.
  • the first list is used to record the application layer ID or layer 2 ID of the reachable group member; or the V2X layer of the terminal determines the third group according to the second list
  • the second list is used to record the layer 2 identification of the reachable group members; or, the V2X layer of the terminal assigns the number of the third group member.
  • the number of the third group member is the third group member's level 2 identification or the third group member's level 1 identification.
  • the method further includes: the AS of the terminal receives the multicast message; the AS of the terminal determines the feedback resource according to the number of the third group member; the AS of the terminal sends the ACK/NACK of the multicast message according to the feedback resource news.
  • the AS of the terminal determines the corresponding feedback resource according to the number of the third group member, thereby ensuring that the AS of the terminal can normally feed back ACK/NACK messages to the multicast sender.
  • the multicast sender does not need to configure corresponding feedback resources for each of the reachable members one by one, which helps to save signaling overhead and also reduces the complexity of the multicast process.
  • the method further includes: the application layer of the terminal sends the application layer identification of the group to the V2X layer of the terminal; the V2X layer of the terminal sends layer 2 of the group to the AS of the terminal according to the application layer identification of the group Logo.
  • a communication method including: the application layer of the terminal sends the application layer identifier of the reachable group member in the group to the V2X layer of the terminal, and the terminal corresponds to the third group member in the group; the V2X layer of the terminal is based on The application layer ID of the reachable group member sends the layer 2 ID of the reachable group member to the AS of the terminal; the AS of the terminal determines the number of reachable group members according to the layer 2 ID of the reachable group member.
  • the AS of the terminal can learn the number of reachable group members, and thus perceive the specific number of group members around the terminal. In this way, the AS of the terminal can determine whether all group members located around the terminal have successfully received multicast information based on whether the number of received ACK messages is equal to the specific number of group members around the terminal. This ensures that the AS of the terminal normally executes the HARQ mechanism of multicast.
  • the method further includes: the AS of the terminal obtains the number of the third group member. Among them, the number of the third group member is used to determine the feedback resources of the third group member.
  • the third group member is one of the reachable group members in the group; the AS of the terminal obtains the number of the third group member, including: the AS of the terminal identifies the layer 2 of the reachable group member Size, determine the number of the third group member; or, the AS of the terminal determines the number of the third group member according to the position of the third group member in the second list, and the second list is used to record the layer 2 of the group member. Identification; or, the AS of the terminal assigns the number of the third group member.
  • the number of the third group member is the third group member's level 2 identification or the third group member's level 1 identification.
  • the method further includes: the AS of the terminal receives the multicast message; the AS of the terminal determines the feedback resource according to the number of the third group member; the AS of the terminal sends the ACK/NACK of the multicast message according to the feedback resource news.
  • the AS of the terminal determines the corresponding feedback resource according to the number of the third group member, thereby ensuring that the AS of the terminal can normally feed back ACK/NACK messages to the multicast sender.
  • the multicast sender does not need to configure corresponding feedback resources for each of the reachable members one by one, which is beneficial to save signaling overhead and also reduces the complexity of implementing the multicast process.
  • the method further includes: the application layer of the terminal sends the application layer identification of the group to the V2X layer of the terminal; the V2X layer of the terminal sends the layer of the group to the AS of the terminal according to the application layer identification of the group 2 Identification.
  • a communication method including: the application layer of the terminal obtains the number of reachable group members in the group, the third group member is a reachable group member in the group; The V2X layer sends the number of reachable group members; the V2X layer of the terminal sends the number of reachable group members to the AS of the terminal.
  • the AS of the terminal can learn the number of reachable group members, and thus perceive the specific number of group members around the terminal. In this way, the AS of the terminal can determine whether all group members located around the terminal have successfully received multicast information based on whether the number of received ACK messages is equal to the specific number of group members around the terminal. This ensures that the AS of the terminal normally executes the HARQ mechanism of multicast.
  • the application layer of the terminal obtains the number of reachable group members in the group, including: the application layer of the terminal obtains the application layer identifier of the reachable group member, and according to the application layer identifier of the reachable group member, Determine the number of reachable group members; or, the application layer of the terminal receives the number of reachable group members sent by the application server; or, the application layer of the terminal receives the number of reachable group members sent by the group management terminal.
  • the application layer of the terminal obtains the application layer identification of the reachable group member, including: the application layer of the terminal receives the application layer identification of the reachable group member sent by the application server; or, the application layer of the terminal receives the group The application layer identifier of the reachable group member sent by the management terminal.
  • the method further includes: the application layer of the terminal obtains the number of the third group member; the application layer of the terminal sends the number of the third group member to the V2X layer of the terminal; and the V2X layer of the terminal sends the AS of the terminal The number of the third group member.
  • the number of the third group member is used to determine the feedback resources of the third group member.
  • the third group member is one of the reachable group members in the group; the application layer of the terminal obtains the number of the third group member, including: the application layer of the terminal is based on the application layer of the reachable group member The size of the identifier determines the number of the third group member; or, the application layer of the terminal determines the number of the third group member according to the position of the third group member in the third list, and the third list is used to record the reachable group members Or, the application layer of the terminal assigns the number of the third group member; or, the application layer of the terminal receives the number of the third group member sent by the application server; or, the application layer of the terminal receives the number sent by the group management terminal The number of the third group member.
  • the method further includes: the AS of the terminal receives the multicast message; the AS of the terminal determines the feedback resource according to the number of the third group member; the AS of the terminal sends the ACK/NACK message of the multicast message according to the feedback resource .
  • the AS of the terminal determines the corresponding feedback resource according to the number of the third group member, thereby ensuring that the AS of the terminal can normally feed back ACK/NACK messages to the multicast sender.
  • the multicast sender does not need to configure corresponding feedback resources for each of the reachable members one by one, which is beneficial to save signaling overhead and also reduces the complexity of implementing the multicast process.
  • the method further includes: the application layer of the terminal sends the application layer identification of the group to the V2X layer of the terminal; the V2X layer of the terminal sends layer 2 of the group to the AS of the terminal according to the application layer identification of the group Logo.
  • a communication device including: a V2X layer module and an AS module.
  • the V2X layer module is used to send a first message, the first message includes the identity of the group, and the communication device corresponds to the first group member of the group; receives the response message of the first message; determines the reachable group in the group according to the response message The number of members; send the number of reachable members to the AS module.
  • the AS module is used to receive the number of reachable group members sent by the V2X layer module.
  • the V2X layer module is also used to obtain the number of the first group member and send the number of the first group member to the AS module.
  • the first group member is one of the reachable group members in the group; the V2X layer module is also used to obtain the number of the first group member, including: according to the application layer identification of the reachable group member Determine the number of the first group member; or, determine the number of the first group member according to the size of the layer 2 identification of the group members; or, assign the number of the first group member.
  • the number of the first group member is the layer 2 ID of the first group member or the layer 1 ID of the first group member.
  • the AS module is also used to receive multicast messages; determine the feedback resource according to the number of the first group member; and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the response message includes the identity of the group and the identity of the second group member in the group, and the second group member is one of the reachable members in the group.
  • the V2X layer module is also used to send a second message to the second terminal corresponding to the second group member.
  • the second message carries the number of reachable group members or the identifier of the reachable group member. At least one.
  • the second message includes any of the following: the number of the reachable group member; or, the number of the second group member; or, the reachable group members except the first group member Number.
  • the second message also includes an identification of the group.
  • a communication device including: a V2X layer module and an AS module.
  • the V2X layer module is used to receive the first message from the first terminal, the first message includes the identifier of the group, the first terminal corresponds to the first group member in the group, and the communication device corresponds to the second group member in the group; Send the response message of the first message to the first terminal; receive the second message sent by the V2X layer of the first terminal; obtain the number of reachable group members according to the second message; send the number of reachable group members to the AS module .
  • the AS module is used to receive the number of reachable group members sent by the V2X layer module.
  • the response message includes the identity of the group and the identity of the second group member.
  • the second message carries at least one of the number of reachable group members or the identification of reachable group members.
  • the second message includes any of the following: the number of the reachable group member; or, the number of the second group member; or, the reachable group members except the first group member Number.
  • the V2X layer module is also used to obtain the number of the second group member according to the second message; and send the number of the second group member to the AS module.
  • the AS module is also used to receive the number of the second group member sent by the V2X layer module.
  • the AS module is also used to receive multicast messages; determine the feedback resource according to the number of the second group member; and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the second message includes the identity of the group.
  • a communication device including: an application layer module, a V2X layer module, and an AS module.
  • the application layer module is used to send the application layer identifier of the reachable group member in the group to the V2X layer module, and the communication device corresponds to the third group member in the group.
  • the V2X layer module is used to receive the application layer ID of the reachable group members sent by the V2X layer module; determine the number of reachable group members according to the application layer ID of the reachable group members; send the reachable group members to the AS module The number of group members.
  • the AS module is used to receive the number of reachable group members sent by the V2X layer module.
  • the V2X layer module is used to determine the number of reachable group members based on the application layer identification of the reachable group members, including: generating/allocating reachable groups according to the application layer identification of the reachable group members The level 2 identification of the members; according to the level 2 identification of the reachable members, the number of reachable members is determined.
  • the V2X layer module is also used to obtain the number of the third group member; send the number of the third group member to the AS module.
  • the AS module is also used to receive the number of the third group member sent by the V2X layer module.
  • the V2X layer module is also used to obtain the number of the third group member, including: determining the number of the third group member according to the size of the application layer identifier of the reachable group member; or, according to the reachable group Determine the number of the third group member based on the size of the level 2 identification of the member; or, determine the number of the third group member according to the position of the third group member in the first list, and the first list is used to record the reachable group members
  • the application layer ID or the layer 2 ID of, or the number of the third group member is assigned.
  • the number of the third group member is the third group member's level 2 identification or the third group member's level 1 identification.
  • the AS module is also used to receive multicast messages; determine the feedback resource according to the number of the third group member; and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the application layer module is also used to send the application layer identification of the group to the V2X layer module.
  • the V2X layer module is also used to receive the application layer identification of the group sent by the application layer module; according to the application layer identification of the group, send the layer 2 identification of the group to the AS module.
  • the AS module is also used to receive the layer 2 identification of the group sent by the V2X layer module.
  • a communication device including: an application layer module, a V2X layer module, and an AS module.
  • the application layer module is used to send the application layer identifier of the reachable group member in the group to the V2X layer module, and the communication device corresponds to the third group member in the group.
  • the V2X layer module is used to receive the application layer identifier of the reachable group member sent by the application layer module; according to the application layer identifier of the reachable group member, send the layer 2 identifier of the reachable group member to the AS module.
  • the AS module is used to receive the layer 2 identifier of the reachable group member sent by the V2X layer module; according to the layer 2 identifier of the reachable group member, determine the number of reachable group members.
  • the AS module is also used to obtain the number of the third group member.
  • the AS module is also used to obtain the number of the third group member, including: determining the number of the third group member according to the size of the layer 2 identifier of the reachable group member; or, according to the second list The position of the third group member is determined by the number of the third group member, and the second list is used to record the layer 2 identification of the reachable group member; or, the number of the third group member is assigned.
  • the number of the third group member is the third group member's level 2 identification or the third group member's level 1 identification.
  • the AS module is also used to receive multicast messages; determine the feedback resource according to the number of the third group member; and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the application layer module is also used to send the application layer identification of the group to the V2X layer module.
  • the V2X layer module is also used to receive the application layer identification of the group sent by the application layer module; according to the application layer identification of the group, send the layer 2 identification of the group to the AS module.
  • the AS module is also used to receive the layer 2 identifier of the group sent by the V2X layer module.
  • a communication device including: an application layer module, a V2X layer module, and an AS module.
  • the application layer module is used to obtain the number of reachable group members in the group, and the communication device corresponds to the third group member in the group; it sends the number of reachable group members to the V2X layer module.
  • the V2X layer module is used to send the number of reachable group members to the AS module.
  • the AS module is used to receive the number of reachable group members sent by the V2X layer module.
  • the application layer module is used to obtain the number of reachable members in the group, including: obtaining the application layer identification of the reachable group member, and determining the reachable group member's application layer identification Up to the number of group members; or, receiving the number of reachable group members sent by the application server/group management terminal.
  • the application layer module is used to obtain the application layer identifier of the reachable group member, including: receiving the application layer identifier of the reachable group member sent by the application server/group management terminal.
  • the application layer module is also used to obtain the number of the third group member; to send the number of the third group member to the V2X layer module.
  • the V2X layer module is also used to send the number of the third group member to the AS module.
  • the AS module is also used to receive the number of the third group member sent by the V2X layer module.
  • the application layer module is also used to obtain the number of the third group member, including: determining the number of the third group member according to the size of the application layer identifier of the reachable group member; or, according to the third list In the position of the third group member, determine the number of the third group member.
  • the third list is used to record the application layer identification of the reachable group member; or, assign the number of the third group member; or, receive from the application server Or the number of the third group member of the group management terminal.
  • the AS module is also used to receive multicast messages; determine the feedback resource according to the number of the third group member; and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the application layer module is also used to send the application layer identification of the group to the V2X layer module.
  • the V2X layer module is also used to receive the application layer identification of the group sent by the application layer module; according to the application layer identification of the group, send the layer 2 identification of the group to the AS module.
  • the AS module is also used to receive the layer 2 identifier of the group sent by the V2X layer module.
  • a communication device including: a processor and a memory, the memory is coupled to the processor, and when the processor executes the instructions stored in the memory, the first aspect to the first aspect can be implemented The communication method described in any one of the five aspects.
  • the terminal may further include a communication interface for the communication device to communicate with other devices.
  • the communication interface may be a transceiver, circuit, bus, module or other types of communication interfaces.
  • a computer-readable storage medium stores instructions that, when run on a computer, can cause the computer to execute any one of the first to fifth aspects above.
  • a computer program product includes instructions that, when run on a computer, enable the computer to execute the communication method involved in any one of the first to fifth aspects.
  • a chip in a fourteenth aspect, includes a processor.
  • the processor executes an instruction, the processor is used to execute the communication method involved in any one of the first to fifth aspects.
  • the instruction can come from the internal memory of the chip or the external memory of the chip.
  • the chip also includes input and output circuits.
  • a communication system including a first terminal and a second terminal.
  • the first terminal is used to execute the communication method involved in any design in the first aspect.
  • the second terminal is used to execute the communication method involved in any design in the second aspect.
  • FIG. 1 is a schematic diagram of the architecture of a communication system provided by an embodiment of the application
  • FIG. 2 is a schematic diagram of a protocol layer of a terminal according to an embodiment of the application
  • FIG. 3 is a schematic structural diagram of a communication device provided by an embodiment of the application.
  • FIG. 4 is a flowchart of a communication method provided by an embodiment of this application.
  • FIG. 5 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 6 is a schematic diagram of a second message provided by an embodiment of this application.
  • FIG. 7 is a schematic diagram of another second message provided by an embodiment of this application.
  • FIG. 8 is a schematic diagram of another second message provided by an embodiment of this application.
  • FIG. 9 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 10 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 11 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 12 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 13 is a schematic structural diagram of a communication device provided by an embodiment of this application.
  • FIG. 14 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 15 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 16 is a flowchart of another communication method provided by an embodiment of this application.
  • FIG. 17 is a flowchart of another communication method provided by an embodiment of this application.
  • A/B can mean A or B.
  • the "and/or” in this article is only an association relationship describing the associated objects, which means that there can be three relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone These three situations.
  • “at least one” means one or more
  • “plurality” means two or more. The words “first” and “second” do not limit the quantity and order of execution, and the words “first” and “second” do not limit the difference.
  • HARQ is a combination of forward error correction (FEC) and automatic repeat-request (ARQ) technologies.
  • FEC forward error correction
  • ARQ automatic repeat-request
  • the HARQ mechanism in the multicast mode mainly refers to: in a group, when a sender member sends a multicast message, other members around the sender member successfully receive the group After broadcasting the message, other group members send response messages (such as ACK message or NACK message) to the sender group member, and then the sender group member determines whether the surrounding group members have successfully received the multicast message according to the received response message. If the sender member determines that at least one member of the surrounding group members has not successfully received the multicast message, the sender member will resend the multicast message.
  • response messages such as ACK message or NACK message
  • the group may be a group in the V2X application, or a group configured by the group management server of the application layer of the terminal.
  • a group can include multiple members.
  • the reachable group members can include some or all of the group members.
  • the group includes member #1, member #2, member #3, and member #4, all reachable members include member #1 and member #2; or, all reachable members include Group member #1, group member #2, group member #3, and group member #4.
  • the reachable member includes other members in the group who can receive the multicast message sent by the member.
  • the reachable group member also includes the group member itself.
  • group #1 includes group member#1-group member#10, assuming group member#2-group member#5 is in the coverage of group member#1, group member#6-group member#10 is in the group Member #1 is outside the coverage area.
  • group member #2-group member #5 can receive group member #1 multicast message, and group member #6-group member #10 cannot receive it Multicast message sent by member #1. Therefore, for member #1, the reachable members include member #2-member #5.
  • the reachable group members also include group member #1.
  • the reachable group member includes other group members located around the group member in the group.
  • the reachable group member also includes the group member itself. It is understandable that other group members located around the group member in the group refer to other group members located in the same geographic area (eg, street, city) as the group member. Alternatively, other group members located around the group member in the group refer to other group members located in the same communication area (for example, a cell, a tracking area) as the group member.
  • group #1 includes group member #1-group member #10
  • group member #1-group member #4 is located in community #1
  • group member #5-group member #10 is located in community #2.
  • the reachable members include member #2 and member #3, and may also include member #1.
  • the reachable group member includes group member #6-group member #10, and can also include group member #5.
  • the terminal corresponds to a member of the group, specifically referring to: a user of the terminal is a member of the group.
  • a user of the terminal is a member of the group.
  • the terminal corresponds to member #1 in the group, it means that the user of the terminal is member #1 in the group.
  • the terminal corresponding to a group member in the group specifically refers to the terminal used by the user as the group member.
  • user #1 is member #1 in the group
  • the terminal corresponding to member #1 is the terminal used by user #1.
  • the user of the terminal may refer to the user of the V2X application of the terminal.
  • the method provided in the embodiments of this application can be used in any communication system that supports V2X service data transmission.
  • the communication system can be a third generation partnership project (3rd generation partnership project, 3GPP) communication system, for example, long term evolution (long term evolution).
  • 3GPP third generation partnership project
  • the LTE) system may also be a fifth generation (5th generation, 5G) mobile communication system or a new radio (NR) system, or a non-3GPP communication system, without limitation.
  • the communication system may include a terminal, an access network device, a core network device, a data network (DN), and the like.
  • DN data network
  • the terminal may be referred to as user equipment (UE) or terminal equipment (terminal).
  • the terminal may be installed with a V2X application (application).
  • the terminal can support V2X communication, such as receiving or sending V2X messages.
  • the terminal can also be called a V2X terminal.
  • V2X messages may include, but are not limited to, vehicle-to-vehicle (V2V) messages, vehicle-to-person (V2P) messages, vehicle-to-network (V2N) messages, vehicle and road infrastructure (vehicle to infrastructure, V2I) information, anti-collision messages between cars, entertainment application messages, navigation messages for interaction between cars, etc.
  • the terminal shown in FIG. 1 may include, but is not limited to, a vehicle-mounted terminal, a mobile phone, a tablet computer or a computer with a wireless transceiver function, a smart gas station, a smart signal lamp, and so on.
  • the terminal may transmit V2X messages through different types of communication interfaces.
  • the communication interface may include a PC5 port and/or a Uu port.
  • the Uu interface is a wireless connection interface between the terminal and the access network device.
  • the PC5 interface is the reference point for the user plane ProSe direct communication of the V2X service between terminals.
  • Access network equipment is responsible for radio resource management, uplink and downlink data classification and QoS applications, as well as complete signaling processing with control plane network elements, and complete data forwarding with user plane network elements.
  • the access network device may be a base station, a broadband network service gateway (BNG), an aggregation switch, a non-3GPP access device, etc.
  • the base station may include various forms of base stations, for example: a macro base station, a micro base station (also referred to as a small station), a relay station, an access point, etc., which are not specifically limited in the embodiment of the present application.
  • the equipment that the terminal accesses to the core network is collectively referred to as the access network equipment in the text, and will not be described.
  • the access network equipment may be the evolved universal terrestrial radio access network (E-UTRAN) equipment in the 4G network, and the next generation radio access network (next generation radio access network) in the 5G network. , NG-RAN) equipment, etc.
  • E-UTRAN evolved universal
  • core network equipment can include access and mobility management functions (AMF), policy control functions (PCF), unified data management (UDM), and session management.
  • AMF access and mobility management functions
  • PCF policy control functions
  • UDM unified data management
  • Function session management function, SMF
  • UPF user plane function
  • application function application function, AF
  • network development function network exposure function, NEF
  • user data repository user data repository
  • the functions of the network elements such as AMF, PCF, UDM, etc. can refer to the existing technology, which will not be repeated here.
  • a network composed of operator network elements other than RAN can become a core network.
  • a 4G network it includes MME, S-GW, P-GW, HSS and other network elements.
  • a 5G network it Including AMF, SMF, UPF, UDM, PCF and other network elements.
  • the protocol layer of the terminal can support the terminal to transmit V2X messages.
  • the protocol layer of the terminal may include: application layer, V2X layer, and AS.
  • the application layer is mainly used to provide V2X services, such as generating V2X messages.
  • the V2X layer is mainly used to determine the communication interface of the V2X message, determine the communication mode of the V2X message on the PC5 interface, establish the PC5 unicast connection, and determine the layer 2 identification of the PC5 communication.
  • the V2X layer of the terminal can be deployed independently in the terminal or in other protocol layers of the terminal, such as: it can be deployed in the non-access stratum (NAS) of the terminal (not shown in Figure 2) in.
  • NAS non-access stratum
  • the actions performed by the V2X layer can be considered to be performed by the NAS and are not restricted.
  • the embodiment of the present application takes the independent deployment of the V2X layer of the terminal in the terminal as an example for description, which is not limited.
  • AS is mainly used to support processes such as public land mobile network (PLMN) selection, cell selection, and resource-free resource management.
  • the radio resource management process includes: a radio resource control (radio resource control, RRC) connection establishment process, a signaling establishment process between a terminal and a core network, a handover process, etc.
  • RRC radio resource control
  • AS also applies for PC5 communication resources for V2X messages sent by the PC5 interface, fills in source and destination layer 2 addresses for V2X messages, and establishes PC5-RRC connections for PC5 unicast communication.
  • FIG. 3 is a schematic diagram of the composition of a communication device 300 according to an embodiment of the application.
  • the communication device 300 may be a terminal or a chip or a system on a chip in the terminal.
  • the communication device 300 includes a processor 301, a communication line 302, and a communication interface 303.
  • the communication device 300 may further include a memory 304.
  • the processor 301, the memory 304, and the communication interface 303 may be connected through a communication line 302.
  • the processor 301 may be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, or a microcontroller. , Programmable logic device (PLD) or any combination of them.
  • the processor 301 may also be any other device with processing functions, such as a circuit, a device, or a software module, without limitation.
  • the communication line 302 is used to transmit information between the components included in the communication device 300.
  • the communication interface 303 is used to communicate with other devices or other communication networks.
  • the other communication network may be Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.
  • the communication interface 303 may be a module, a circuit, a transceiver or any device capable of implementing communication.
  • the memory 304 is used to store instructions. Among them, the instructions can be computer programs.
  • the memory 304 may be a read-only memory (read-only memory, ROM) or other types of static storage devices that can store static information and/or instructions, or it may be an access memory (random access memory, RAM) or can store Other types of dynamic storage devices for information and/or instructions can also be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory, CD-ROM ) Or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, etc., are not restricted.
  • EEPROM electrically erasable programmable read-only memory
  • CD-ROM compact disc read-only memory
  • optical disc storage including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.
  • magnetic disk storage media or other magnetic storage devices, etc. are not restricted.
  • the memory 304 can exist independently of the processor 301 or can be integrated with the processor 301.
  • the memory 304 may be used to store instructions or program codes or some data.
  • the memory 304 may be located in the communication device 300 or outside the communication device 300, without limitation.
  • the processor 301 is configured to execute instructions stored in the memory 304 to implement the communication method provided in the following embodiments of the present application.
  • the processor 301 may execute instructions stored in the memory 304 to implement the steps performed by the sending end in the following embodiments of the present application.
  • the processor 301 may include one or more CPUs, such as CPU0 and CPU1 in FIG. 3.
  • the communication device 300 includes multiple processors.
  • the processor 301 in FIG. 3 it may also include a processor 307.
  • the communication apparatus 300 further includes an output device 305 and an input device 306.
  • the input device 306 is a device such as a keyboard, a mouse, a microphone, or a joystick
  • the output device 305 is a device such as a display screen and a speaker.
  • a communication method provided by an embodiment of this application includes the following steps:
  • the V2X layer of the first terminal sends a first message.
  • the foregoing first message may include an identifier of the group.
  • the identification of the group may include: the application layer identification and/or the layer 2 identification of the group.
  • the first message includes the identifier of the group, which may be used to indicate the group corresponding to the first message.
  • the first message can be used to discover other reachable group members in the group except the first group member corresponding to the first terminal.
  • the first message may be used to discover group members located around the first group member corresponding to the first terminal in the group.
  • the first message may also be called a group member report (group member report), and the embodiment of the present application is not limited thereto.
  • the first terminal may correspond to a first group member in the group, and the first group member may be one of the reachable group members in the group.
  • the first message further includes: indication information and an identifier of the first group member.
  • the indication information may be used to indicate the response message for feeding back the first message.
  • the identification of the first group member may include the application layer identification and/or the layer identification of the first group member.
  • the application layer of the first terminal when the V2X application of the first terminal triggers the multicast service, the application layer of the first terminal sends a service trigger indication message to the V2X layer of the first terminal. After that, the V2X layer of the first terminal sends the first message in a multicast/broadcast manner.
  • the application layer of the first terminal when the application layer of the first terminal establishes/updates the V2X group, the application layer of the first terminal sends the V2X group establishment/update instruction information to the V2X layer of the first terminal. After that, the V2X layer of the first terminal sends the first message in a multicast/broadcast manner.
  • the above-mentioned service trigger indication information and the V2X group establishment/update indication information may both include the application layer identification of the group, and may also include the application layer identification of the first group member.
  • the V2X layer of the second terminal receives the first message from the first terminal.
  • the second terminal may be a terminal corresponding to any member (may be referred to as a second member) in the group except the first member.
  • the terminal is the second terminal.
  • the user of terminal #1 is a member of group #1
  • the user of terminal #2 is a member of group #2
  • the user of terminal #3 is a member of group #1
  • terminal # User 4 is a member of group #1.
  • the V2X layer of terminal #1 sends a first message, and the first message includes the identity of group #1.
  • the V2X layer of terminal #2, the V2X layer of terminal #3, and the V2X layer of terminal #4 all receive the first message from terminal #1. Since the user of terminal #2 is not a member of group #1, the second terminal does not include terminal #2. The user of terminal #3 and the user of terminal #4 are group members in group #1, so the second terminal may be at least one of terminal #3 and terminal #4.
  • the V2X layer of the second terminal can receive the first message from the first terminal, the second terminal is located around the first terminal, that is, the second group member corresponding to the second terminal is located The periphery of the first group member corresponding to the first terminal. In this way, the second group member corresponding to the second terminal is also one of the reachable group members in the group.
  • the V2X layer of the second terminal sends a response message of the first message.
  • the above response message may include: the identity of the group and the identity of the second group member.
  • the identification of the second group member may include the application layer identification and/or the layer 2 identification of the second group member. It should be noted that the group identifier included in the above response message and the group identifier included in the first message may be the same group identifier.
  • the above response message may have other names, for example, group member report response (group member report ack), and the embodiment of the present application is not limited to this.
  • the V2X layer of the second terminal obtains the application layer identification of the group from the application layer of the second terminal; and generates/assigns the layer 2 identification of the group according to the application layer identification of the group.
  • the V2X layer of the second terminal can store the group identification.
  • the V2X layer of the second terminal determines whether the identifier of the group stored by itself matches the identifier of the group included in the first message. If the identifier of the group stored by itself is the same as the identifier of the group included in the first message, the V2X layer of the second terminal sends a response message of the first message.
  • the V2X layer of the second terminal allocates the layer 2 identifier of the group according to the application layer identifier of the group, which specifically means that the V2X layer of the second terminal randomly allocates a layer 2 identifier of the group.
  • the V2X layer of the second terminal generates the layer 2 identifier of the group according to the application layer identifier of the group, which specifically means: the V2X layer of the second terminal according to the preset algorithm/first correspondence relationship, and the application layer of the group ID, generate the layer 2 ID of the group.
  • the first correspondence relationship refers to the correspondence relationship between the application layer identifier of the group and the layer 2 identifier of the group.
  • Table 1 is an example of the first correspondence. To illustrate with reference to Table 1, assuming that the application layer identifier of the group is 11, the V2X layer of the second terminal can determine that the layer 2 identifier of the group is 1111110000000000.
  • the V2X layer of the first terminal receives a response message of the first message.
  • the V2X layer of the first terminal may receive one or more response messages to the first message.
  • the V2X layer of the first terminal determines the number of reachable group members according to the response message.
  • the V2X layer of the first terminal determines the number of reachable group members according to the number of response messages received.
  • the number of reachable group members can be equal to the received response message Add 1 to the number of.
  • the number of reachable members in the group #1 may be 2.
  • the number of reachable members can be equal to the received response message The number of.
  • the number of reachable members in group #1 may be 2.
  • the V2X layer of the first terminal sends the number of reachable group members to the AS of the first terminal.
  • the AS of the first terminal receives the number of reachable group members.
  • the AS of the first terminal can learn the specific number of group members located around the first terminal in the group. Specifically, when the first group member is not one of the reachable group members in the group, the number of group members located around the first terminal in the group is equal to the number of reachable group members. In the case where the first group member is one of the reachable group members in the group, the number of group members located around the first terminal in the group is equal to the number of reachable group members minus one.
  • the V2X layer of the first terminal also sends the layer 2 identifier of the group and/or the layer 2 identifier of the first group member to the AS of the first terminal.
  • the V2X layer of the first terminal sends a first message to trigger group members around the first group member in the group to send a response message to the first message, so that the V2X layer of the first terminal can send a first message according to the first message.
  • the response message of the message determines the number of reachable group members.
  • the V2X layer of the first terminal sends the number of reachable group members to the AS of the first terminal. In this way, the AS of the first terminal can determine the specific number of group members located around the first group member in the group according to the number of reachable group members.
  • the AS of the first terminal judges whether the group members around the first terminal are based on the number of reachable group members and the number of ACK messages received. All successfully received the multicast message to ensure the normal execution of the HARQ mechanism.
  • the communication method shown in FIG. 4 further includes steps S107-S109, as described below.
  • the V2X layer of the first terminal sends a second message to the V2X layer of the second terminal.
  • the second message can be used to enable the V2X layer of the second terminal to obtain the number of reachable group members.
  • the second message may carry at least one of the number of reachable group members and the identifier of the reachable group member.
  • the identifier of the reachable group member may include: the identifier of the first group member and the identifiers of all the second group members.
  • the second message further includes an identifier of the group.
  • the second message may also include the identifier of the first group member.
  • the second message is a group information notification (group information notification), and the embodiment of the present application is not limited to this.
  • the V2X layer of the first terminal sends the second message in a unicast manner.
  • the V2X layer of the first terminal sends the second message in a multicast/broadcast manner. It can be understood that, compared to the unicast mode, the second message is sent in the multicast/broadcast mode, which is beneficial to saving signaling overhead.
  • the embodiment of the present application does not limit the order in which the V2X layer of the first terminal performs steps S106 and S107.
  • the V2X layer of the first terminal may perform step S106 first, and then perform step S107; or, perform step S107 first, and then perform step S106; or, perform steps S106 and S107 at the same time.
  • the V2X layer of the second terminal obtains the number of reachable group members according to the second message.
  • the V2X layer of the second terminal can directly obtain the number of reachable group members by parsing the second message.
  • the V2X layer of the second terminal obtains the identification of the reachable group member by analyzing the second message;
  • the V2X layer of the terminal determines the number of reachable group members based on the identification of the reachable group members. It is understandable that the number of reachable group members is equal to the number of reachable group member IDs.
  • the second message includes the identity of reachable member #1, the identity of reachable member #2, the identity of reachable member #3, and the identity of reachable member #4, then the second message
  • the V2X layer of the terminal can determine that the number of reachable group members is 4.
  • the V2X layer of the second terminal sends the number of reachable group members to the AS of the second terminal.
  • the AS of the second terminal obtains the number of reachable group members.
  • the V2X layer of the second terminal also sends the layer 2 identifier of the group and/or the layer 2 identifier of the second group member to the AS of the second terminal.
  • the V2X layer of the second terminal receives the first message; when the second group member corresponding to the second terminal belongs to the group corresponding to the first message, the V2X layer of the second terminal sends a response to the first message Message so that the first terminal knows that the group member corresponding to the second terminal is located around the first terminal. After that, the V2X layer of the second terminal receives the second message, and obtains the number of reachable group members according to the second message. The V2X layer of the second terminal sends the number of reachable group members to the AS of the second terminal.
  • the AS of the second terminal determines whether the group members around the second terminal are based on the number of reachable group members and the number of ACK messages received. All successfully received the multicast message to ensure the normal execution of the HARQ mechanism.
  • FIG. 5 another communication method is provided, which is implemented on the basis of the communication method shown in Fig. 4, specifically, after step S104, steps S201-S202 are further included.
  • the V2X layer of the first terminal obtains the number of the first group member.
  • the number of the first group member may be the layer 2 identification, the layer 1 identification, or other parameters of the first group member.
  • the layer 1 identifier may be obtained by truncating the layer 2 identifier.
  • the layer 1 identifier is the truncated layer 2 identifier. For example, suppose the truncation process refers to truncating the first 10 bits of the layer 2 identification, and only the bits after the 11th bit of the layer 2 identification are retained. If the layer 2 identification of the first group member is 0011001111110001, the first The member’s level 1 is identified as 110001.
  • the V2X layer of the first terminal can adopt any of the following implementation methods Species to get the number of the first group member.
  • Implementation mode 1 The V2X layer of the first terminal determines the number of the first group member according to the size of the application layer identifier of the reachable group member.
  • the V2X layer of the first terminal sorts the application layer identifiers of all reachable group members according to their size, and according to the sequence number of the application layer identifier of the first group member in the first arrangement order/second arrangement order, as The number of the first group member.
  • the first arrangement order refers to the arrangement order of the application layer identifiers of all reachable group members from small to large.
  • the second arrangement order refers to the arrangement order of the application layer identifiers of all reachable group members from largest to smallest.
  • the starting sequence number may be any natural number, such as 0.
  • the first sequence can be: the application layer ID of reachable member #1, the application layer ID of reachable member #4, the application layer ID of reachable member #3, and the reachable member #2 The application layer ID. Assuming that the starting sequence number of the first permutation sequence is 0, therefore, the sequence number of the application layer ID of reachable group member #1 in the first sequence is 0, and the application layer ID of reachable group member #4 is in the first sequence.
  • the sequence number in is 1, the number of the application layer identifier of reachable group member #3 in the first arrangement sequence is 2, and the sequence number of the application layer identifier of reachable group member #2 in the first arrangement sequence is 3. In this way, if the first group member is reachable group member #3, the V2X layer of the first terminal can be the first group member's number 2.
  • the V2X layer of the first terminal determines the number of the first group member according to the size of the layer 2 identifier of the reachable group member.
  • the V2X layer of the first terminal sorts the layer 2 identifiers of all reachable group members according to their size, and according to the sequence number of the first group member's layer 2 identifier in the third arrangement order/fourth arrangement order, as The number of the first group member.
  • the third arrangement order refers to the arrangement order of the layer 2 identifiers of all reachable group members from small to large.
  • the fourth arrangement order refers to the arrangement order of the layer 2 identifiers of all reachable group members from largest to smallest.
  • the starting sequence number may be any natural number, such as 0.
  • the third arrangement sequence can be: reachable member #1's layer 2 identification, reachable member #4's layer 2 identification, reachable member #3's layer 2 identification, reachable member #2 The layer 2 logo.
  • the sequence number of the layer 2 identifier of reachable member #1 in the third permutation sequence is 0, and the layer 2 label of reachable group member #4 is in the third permutation sequence
  • the sequence number in is 1, the sequence number of the layer 2 identifier of reachable member #3 in the third permutation sequence is 2, and the sequence number of the layer 2 label of reachable member #2 in the third permutation sequence is 3. In this way, if the first group member is reachable group member #3, the V2X layer of the first terminal can determine that the number of the first group member is 2.
  • Implementation mode 3 The V2X layer of the first terminal allocates the number of the first group member.
  • the value range of the number is determined according to the number of reachable group members. For example, if the number of reachable group members is 10, the value of the number can be selected from an integer from 0 to 9, or the value of the number can be selected from an integer from 1 to 10.
  • the number assigned to the first group member will not be assigned to other group members among the reachable group members. In other words, in a group, two different members of the reachable member have two different numbers.
  • the V2X layer of the first terminal needs to be assigned 10 numbers, and these 10 numbers can be 0, 1, 2, 3, 4, 5, respectively. 6,7,8,9.
  • the V2X layer of the first terminal can randomly select a number (for example, number 9) from among the 10 numbers and assign it to the first group member.
  • the V2X layer of the first terminal sends the number of the first group member to the AS of the first terminal.
  • the embodiment of the present application does not limit the execution sequence of steps S201-S202 and steps S105-S106. That is to say, the V2X layer of the first terminal can perform steps S201-S202 first, and then steps S105-S106; or, perform steps S105-S106 first, and then perform steps S201-S202; or, perform steps S105-S106 at the same time, And steps S201-S202.
  • step S202 and step S106 are performed at the same time at the V2X layer of the first terminal, the number of the first group member and the number of reachable group members may be carried in the same message.
  • the AS of the first terminal can learn the number of the first group member. Therefore, after the AS of the first terminal receives the multicast message, the AS of the first terminal can determine the corresponding feedback resource according to the number of the first group member, and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the AS of the first terminal can determine the corresponding feedback resource according to the number of the first group member, and send the ACK/NACK message of the multicast message according to the feedback resource.
  • step S104 the communication method further includes the step S206-S207.
  • the V2X layer of the first terminal obtains the numbers of all the group members except the first group member among the reachable group members.
  • the number of each group member among all other group members may be the layer 2 identification, layer 1 identification or other parameters of the group member.
  • the V2X layer of the first terminal can adopt any one of the following implementation manners to obtain the numbers of all other group members.
  • Implementation mode 1 The V2X layer of the first terminal determines the numbers of all other group members according to the size of the application layer identifiers of all reachable group members.
  • Implementation mode 2 The V2X layer of the first terminal determines the numbers of all other group members according to the size of the layer 2 identifiers of all reachable group members.
  • Implementation mode 3 The V2X layer of the first terminal allocates the numbers of all other group members.
  • Implementation manner 4 The V2X layer of the first terminal determines the numbers of all other group members according to the response message.
  • the response message includes indication information for indicating the number of the reachable group member.
  • step S201 For the specific details of the foregoing implementation manner 1 to implementation manner 3, reference may be made to the description in step S201, which will not be repeated here.
  • the V2X layer of the first terminal sends the numbers of all other group members to the AS of the first terminal.
  • the embodiment of the present application does not limit the execution sequence of steps S206-S202 and steps S105-S106. That is to say, the V2X layer of the first terminal can perform steps S201-S207 first, and then steps S105-S106; or, perform steps S105-S106 first, and then perform steps S206-S207; or, perform steps S105-S106 at the same time, And steps S206-S207.
  • the AS of the first terminal can learn the numbers of all the group members except the first group member among all the reachable group members.
  • the embodiment shown in FIG. 5 and the embodiment shown in FIG. 14 may be executed together, or may be executed separately, which is not limited in this application.
  • the communication method shown in FIG. 4 may further include steps S203-S204 after step S107.
  • the V2X layer of the second terminal obtains the number of the second group member.
  • the number of the second group member may be the layer 2 identification, the layer 1 identification, or other parameters of the second group member.
  • the V2X layer of the second terminal can obtain the number of the second group member according to the second message.
  • the second message indicates the number of the second group member in an implicit manner.
  • the second message includes the identification of the reachable group member.
  • the V2X layer of the second terminal can obtain the identifier of the reachable group member from the second message.
  • the V2X layer of the second terminal determines the number of the second group member according to the size of the application layer ID/layer 2 ID of the reachable group member. For the manner of determining the number of the second group member, reference may be made to the related description of the first implementation or the second implementation in step S201.
  • the position of the group member's identifier in the second message corresponds to the group member's number. Therefore, the V2X layer of the second terminal determines the number of the second group member according to the position of the second group member's identifier in the second message.
  • the identity of member #1 is located in the first position in the second message
  • the identity of member #2 is located in the second position in the second message
  • the identity of member #3 is located in the second message.
  • the first position in the second message corresponds to number 1
  • the second position in the second message corresponds to number 2
  • the third position in the second message corresponds to number 3.
  • the V2X layer of the second terminal can determine that the number of the second group member is 3.
  • the second message indicates the number of the second group member in an explicit manner.
  • the second message includes the number of the second group member.
  • the V2X layer of the second terminal can directly obtain the number of the second group member by parsing the second message.
  • the V2X layer of the first terminal sends the second message to the second group in a unicast manner.
  • the V2X layer of the terminal sends the second message to the second group in a unicast manner.
  • the second message may include the number of reachable group members.
  • the second message may also include the numbers of all the group members except the first group member among the reachable group members.
  • the second message includes the number of the reachable group member to specifically explain how the V2X layer of the second terminal determines the number of the second group member. It is understandable that, in the case that the second message includes the numbers of all the other members of the group except the first group member, the way in which the V2X layer of the second terminal determines the number of the second group member is also You can refer to the corresponding description below.
  • the second message includes the number of the reachable group member and the identifier of the reachable group member.
  • the position of the group member's identifier in the second message may implicitly indicate the position of the group member's number in the second message. Therefore, since the V2X layer of the second terminal knows the identification of the second group member in advance, the V2X layer of the second terminal can first determine the position of the identification of the second group member in the second message, thereby determining the number of the second group member The position in the second message determines the number of the second group member.
  • the position of the group member’s identifier in the second message implicitly indicates that the number of the group member is in the second message
  • the second message includes a first information element and a second information element.
  • the first information element is used to carry the identifier of the reachable group member
  • the second information element is used to carry the number of the reachable group member.
  • the position of the group member's identifier in the first cell is the same as the position of the group member's number in the second cell.
  • the V2X layer of the second terminal determines the position of the second group member's number in the second cell by determining the position of the second group member's identifier in the first cell. In this way, the V2X layer of the second terminal can obtain the number of the second group member from the second cell.
  • the identity of group member #1 is in the first position in the first cell
  • the identity of group member #2 is in the second position in the first cell
  • group member# The identifier of 3 is in the third position in the first cell.
  • the number of member #1 is in the first position in the second cell
  • the number of member #2 is in the second position in the second cell
  • the number of member #3 is in the third position in the second cell.
  • the V2X layer of the second terminal first determines that the identity of group member #3 is located in the third position in the first cell, so that the V2X layer of the second terminal starts from the first cell of the second cell. Get the number of member #3 in three positions.
  • the second message includes M cells, and M is equal to the number of reachable group members.
  • M is equal to the number of reachable group members.
  • One cell in the M cells corresponds to one group member, and one cell is used to carry the identification and number of the corresponding group member.
  • the V2X layer of the second terminal determines the information element used to carry the identification of the second group member in the second information, thereby obtaining it from the information element used to carry the identification of the second group member in the second information To the number of the second group member.
  • the identity and number of member #1 are carried in cell #1 of the second message, and the identity and number of member #2 are carried in cell #2 of the second message, and member# The identification and number of 3 are carried in the cell #3 of the second message.
  • the V2X layer of the second terminal can determine cell #2 according to the identification of group member #2, and obtain the number of group member #2 from cell #2.
  • the V2X layer of the second terminal sends the number of the second group member to the AS of the second terminal, so that the AS of the second terminal receives the number of the second group member sent by the V2X layer of the second terminal.
  • the embodiment of the present application does not limit the execution sequence of steps S203-S204 and steps S108-S109.
  • the V2X layer of the second terminal can first perform steps S203-S204, and then perform steps S108-S109; or, perform steps S108-S10 first, and then perform steps S203-S204; or, perform steps S203-S204 at the same time, And steps S108-S109.
  • the number of the second group member and the number of reachable group members may be carried in the same message.
  • the AS of the second terminal can learn the number of the second group member. Therefore, after the AS of the second terminal receives the multicast message, the AS of the second terminal can determine the corresponding feedback resource according to the number of the second group member, and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the AS of the second terminal can determine the corresponding feedback resource according to the number of the second group member, and send the ACK/NACK message of the multicast message according to the feedback resource.
  • the communication method further includes step S205 before step S107.
  • step S201 For the specific implementation manner for the first terminal to obtain the number of the second group member, reference may be made to the related description in step S201, which will not be repeated here.
  • step S201 does not limit the execution sequence of step S201 and step S205.
  • a communication method provided in an embodiment of this application includes the following steps:
  • the application layer of the terminal sends the application layer identifier of the reachable group member to the V2X layer of the terminal.
  • the V2X layer of the terminal receives the application layer identifier of the reachable group member sent by the application layer of the terminal.
  • the terminal corresponds to the third member of the group.
  • the third group member can be one of the reachable group members in the group.
  • the trigger conditions for the application layer of the terminal to execute step S301 include but are not limited to: the V2X application of the terminal triggers the multicast service, the establishment of the group, and the update of the group.
  • the application layer of the terminal obtains the application layer identifier of the reachable group member in the group; then, the application layer of the terminal sends the application layer identifier of the reachable group member to the V2X layer of the terminal.
  • the application layer of the terminal obtains the application layer identifier of the reachable group member in the group, including: the application layer of the terminal receives the application layer identifier of the reachable group member sent by other devices (for example, an application server or a group management terminal) .
  • the group management terminal is a terminal used to manage groups, and has functions such as creating groups, updating group members, and deleting groups.
  • the group management terminal corresponds to the management group members in the group, and the management group members are used to manage the group and have functions such as creating groups, updating group members, and deleting groups.
  • the V2X layer of the terminal obtains the number of reachable group members according to the application layer identifier of the reachable group members.
  • the V2X layer of the terminal counts the number of application layer identifiers of reachable group members, and obtains the number of reachable group members. Among them, the number of reachable group members is equal to the number of application layer identifiers of reachable group members.
  • the V2X layer of the terminal receives the application layer identification of group member #1, the application layer identification of group member #3, the application layer identification of group member #5, the application layer identification of group member #6, and the application layer identification of group member #7.
  • Application layer identification the V2X layer of the terminal can determine that the number of application layer identifications of reachable group members is 5, so that the V2X layer of the terminal determines that the number of reachable group members is 5.
  • the V2X layer of the terminal generates/assigns the layer 2 ID of the reachable group member according to the application layer ID of the reachable group member; after that, the V2X layer of the terminal counts the number of the layer 2 ID of the reachable group member. Count, get the number of reachable group members. Among them, the number of reachable group members is equal to the number of layer 2 identifiers of reachable group members.
  • the V2X layer of the terminal allocates the layer 2 identifier of the reachable group member according to the application layer identifier of the reachable group member. Specifically, this means that the V2X layer of the terminal randomly allocates a layer 2 identifier of the reachable group member.
  • the V2X layer of the terminal generates the layer 2 identifier of the reachable group member according to the application layer identifier of the reachable group member. Specifically, it refers to the V2X layer of the terminal according to the preset algorithm/second correspondence relationship, and the application of the reachable group member Layer ID, generate layer 2 ID that can reach group members.
  • the second correspondence refers to the correspondence between the application layer identifier of the group member and the layer 2 identifier of the group member.
  • Table 2 is an example of the second correspondence. To illustrate with Table 2, assuming that the application layer identifier of one of the reachable members is 1101, the V2X layer of the terminal can determine that the layer 2 identifier of the member is 111101011001001. Assuming that the application layer identifier of one of the reachable group members is 1111, the V2X layer of the terminal can determine that the layer 2 identifier of the group member is 111101011001101.
  • the V2X layer of the terminal sends the number of reachable group members to the AS of the terminal.
  • the AS of the terminal receives the number of reachable group members sent by the V2X layer of the terminal.
  • the AS layer of the terminal can know the number of reachable group members, so as to ensure that the AS of the terminal can execute the HARQ mechanism in the multicast mode.
  • the communication method further includes steps S304-S305.
  • the V2X layer of the terminal obtains the number of the third group member.
  • the number of the third group member may be the layer 2 identification, layer 1 identification or other parameters of the third group member.
  • the V2X layer of the terminal can be based on any of the following implementations To determine the number of the third group member.
  • Implementation mode 1 The V2X layer of the terminal determines the number of the third group member according to the size of the application layer identifier of the reachable group member.
  • the V2X layer of the terminal determines the number of the third group member according to the size of the layer 2 identifier of the reachable group member.
  • Implementation mode three the V2X layer of the terminal allocates the number of the third group member.
  • Implementation manner 4 The V2X layer of the terminal determines the number of the third group member according to the position of the third group member in the first list.
  • the first list is used to record the application layer identification or layer 2 identification of the reachable group members.
  • the V2X layer of the terminal determines the number of the third group member according to the position of the third group member's application layer ID/layer 2 ID in the first list. For example, in the case that the first list records an application layer ID/layer 2 ID of the group member in one column/row, the V2X layer of the terminal can use the third group member’s application layer ID/layer 2 ID in the column/ The serial number of the row, as the number of the first reachable group member.
  • the first list is used to record the application layer identifiers of reachable group members
  • Table 3 is an example of the first list.
  • the application layer identifier of the third group member is 1101
  • the application layer identifier of the third group member is in the first row of the first list.
  • the sequence number of the first row is 0.
  • the V2X layer of the terminal can determine that the number of the third group member is 0.
  • the first list is used to record the layer 2 identifiers of reachable members.
  • Table 4 is an example of the first list. Assuming that the layer 2 identifier of the third group member is 111101011001001, it can be seen that the layer 2 identifier of the third group member is in the first row of the first list. Suppose that when the rows in the first list are sorted from 0, the sequence number of the first row is 0. In this way, the V2X layer of the terminal can determine that the number of the third group member is 0.
  • the V2X layer of the terminal sends the number of the third group member to the AS of the terminal.
  • the AS of the terminal receives the number of the third group member sent by the V2X layer of the terminal.
  • steps S302-S303 may be performed first, and then steps S304-S305; or, steps S304-S305 may be performed first, and then steps S302-S303 may be performed, or steps S302-S303, and steps S304-S305 may be performed simultaneously.
  • the AS of the terminal can learn the number of the third group member, so as to ensure that after the AS of the terminal receives the multicast message, the AS of the terminal can correctly feed back the ACK/NACK message of the multicast message.
  • the AS of the terminal can correctly feed back the ACK/NACK message of the multicast message.
  • step S301 the communication method further includes the step S306-S307.
  • the V2X layer of the terminal obtains the numbers of all members except the third member among the reachable members.
  • the number of each group member among all other group members may be the layer 2 identification, layer 1 identification or other parameters of the group member.
  • the V2X layer of the terminal can determine the numbers of all other group members according to any of the following implementation methods.
  • Implementation mode 1 The V2X layer of the terminal determines the numbers of all other group members according to the size of the application layer identifier of the reachable group members.
  • Implementation mode 2 The V2X layer of the terminal determines the numbers of all other group members according to the size of the layer 2 identification of the reachable group members.
  • Implementation mode 3 The V2X layer of the terminal allocates the numbers of all other group members.
  • Implementation mode 4 The V2X layer of the terminal determines the number of each member of all other members according to the position of each member of all other members in the first table.
  • the V2X layer of the terminal sends the numbers of all the group members except the third group member among the reachable group members to the AS of the terminal.
  • steps S302-S303 may be performed first, and then steps S306-S307; or, steps S306-S307 may be performed first, and then steps S302-S303 may be performed, or steps S302-S303, and steps S306-S307 may be performed simultaneously.
  • the AS of the terminal can obtain the numbers of all members except the third member among the reachable members.
  • a communication method provided in an embodiment of this application includes the following steps:
  • the application layer of the terminal sends the application layer identifier of the reachable group member to the V2X layer of the terminal.
  • the V2X layer of the terminal receives the application layer identifier of the reachable group member.
  • step S401 For the specific description of step S401, please refer to step S301, which will not be repeated here.
  • the V2X layer of the terminal sends the layer 2 identifier of the reachable group member to the AS of the terminal according to the application layer identifier of the reachable group member.
  • the AS of the terminal receives the layer 2 identifier of the reachable group member.
  • the V2X layer of the terminal generates/assigns the layer 2 identifier of the reachable group member according to the application layer identifier of the reachable group member; after that, the V2X layer of the terminal sends the layer 2 reachable group member to the AS of the terminal.
  • the AS of the terminal obtains the number of reachable group members according to the layer 2 identification of the reachable group members.
  • the number of reachable group members is equal to the number of layer 2 identifiers of reachable group members.
  • the AS layer of the terminal can learn the number of reachable group members, thereby ensuring that the AS of the terminal can execute the HARQ mechanism in the multicast mode.
  • the communication method further includes step S404.
  • the AS of the terminal obtains the number of the third group member.
  • the number of the third group member may be the layer 2 identification, layer 1 identification or other parameters of the third group member.
  • the AS of the terminal can be based on any one of the following implementation modes: Determine the number of the third group member.
  • Implementation mode 1 The AS of the terminal determines the number of the third group member according to the size of the layer 2 identifier of the reachable group member.
  • Implementation mode 3 The AS of the terminal determines the number of the third group member according to the position of the third group member in the second list. Among them, the second list is used to record the layer 2 identifiers of reachable group members.
  • step S304 in the embodiment shown in FIG. 9, which is not repeated here.
  • step S403 may be executed first, and then step S404; or, step S404 may be executed first, and then step S403 may be executed, or steps S403 and S404 may be executed simultaneously.
  • the AS of the terminal can learn the number of the third group member, so as to ensure that after the AS of the terminal receives the multicast message, the AS of the terminal can correctly feed back the ACK/NACK message of the multicast message.
  • the AS of the terminal can correctly feed back the ACK/NACK message of the multicast message.
  • another communication method is provided.
  • the communication method is implemented on the basis of the communication method shown in FIG. 10. Specifically, after step S403, the communication method further includes the step S405.
  • the AS of the terminal obtains the numbers of all members except the third member among the reachable members.
  • the number of each group member among all other group members may be the layer 2 identification, layer 1 identification or other parameters of the group member.
  • the V2X layer of the terminal can determine the numbers of all other group members according to any of the following implementation methods.
  • Implementation mode 1 The V2X layer of the terminal determines the numbers of all other group members according to the size of the layer 2 identification of the reachable group members.
  • Implementation mode two the V2X layer of the terminal allocates the numbers of all other group members.
  • Implementation mode 3 The V2X layer of the terminal determines the number of each member of all other members according to the position of each member of all other members in the first form.
  • step S404 in the embodiment shown in FIG. 10, which is not repeated here.
  • the AS of the terminal can learn the numbers of all the group members except the third group member among the reachable group members.
  • a communication method provided in an embodiment of this application includes the following steps:
  • S501 The application layer of the terminal obtains the number of reachable group members.
  • the terminal corresponds to the third member of the group.
  • the trigger condition for the application layer of the terminal to execute step S501 includes but is not limited to: the V2X application of the terminal triggers the multicast service, the establishment of the group, and the update of the group.
  • the application layer of the terminal obtains the application layer identifier of the reachable group member; then, the application layer of the terminal obtains the number of reachable group members according to the application layer identifier of the reachable group member.
  • the number of reachable group members is equal to the number of application layer identifiers of reachable group members.
  • the application layer of the terminal obtains the application layer identifier of the reachable group member in the group, including: the application layer of the terminal receives the application layer identifier of the reachable group member sent by other devices (for example, an application server or a group management terminal) .
  • S502 The application layer of the terminal sends the number of reachable group members to the V2X layer of the terminal.
  • the V2X layer of the terminal receives the number of reachable group members.
  • S503 The V2X layer of the terminal sends the number of reachable group members to the AS of the terminal.
  • the AS of the terminal receives the number of reachable group members.
  • the AS of the terminal knows the number of reachable group members to ensure that the AS of the terminal can normally execute the HARQ mechanism in the multicast mode.
  • the communication method further includes steps S504-S506. S504.
  • the application layer of the terminal obtains the number of the third group member.
  • the number of the third group member may be the layer 2 identification, layer 1 identification or other parameters of the third group member.
  • the application layer of the terminal can be based on any of the following implementations To determine the number of the third group member.
  • Implementation mode 1 The application layer of the terminal determines the number of the third group member according to the size of the application layer identifier of the reachable group member.
  • Implementation mode 2 The application layer of the terminal allocates the number of the third group member.
  • Implementation manner 3 The application layer of the terminal determines the number of the third group member according to the position of the third group member in the third list. Among them, the third list is used to record the application layer identifiers of reachable group members.
  • step S304 in the embodiment shown in FIG. 9, which is not repeated here.
  • Implementation manner 4 The application layer of the terminal receives the number of the third group member from the application server or the group management terminal.
  • S505 The application layer of the terminal sends the number of the third group member to the V2X layer of the terminal. Correspondingly, the V2X layer of the terminal receives the number of the third group member.
  • S506 The V2X layer of the terminal sends the number of the third group member to the AS of the terminal.
  • the AS of the terminal receives the number of the third group member.
  • steps S501-S503 can be performed first, and then steps S504-S506; or, steps S504-S506 can be performed first, and then steps S501-S503, or steps S501-S503, and S504-S506 can be performed simultaneously.
  • the AS of the terminal can learn the number of the third group member, so as to ensure that after the AS of the terminal receives the multicast message, the AS of the terminal can correctly feed back the ACK/NACK message of the multicast message.
  • the AS of the terminal can correctly feed back the ACK/NACK message of the multicast message.
  • FIG. 17 another communication method is provided, and the communication method is implemented on the basis of the communication method shown in FIG. 10. Specifically, the communication method further includes steps S507-S509.
  • S507 The application layer of the terminal obtains the numbers of all members except the third member among the reachable members.
  • the number of each group member among all other group members may be the layer 2 identification, layer 1 identification or other parameters of the group member.
  • the application layer of the terminal can determine the numbers of all other group members according to any one of the following implementation methods.
  • Implementation mode 1 The application layer of the terminal determines the numbers of all other reachable group members according to the size of the application layer identifier of the reachable group members.
  • Implementation mode 2 The application layer of the terminal allocates the numbers of all other reachable members.
  • Implementation mode 3 The application layer of the terminal determines the number of each member of all other members according to the position of each member of all other members in the third list.
  • Implementation manner 4 The application layer of the terminal receives the numbers of all other group members sent from the application server or the group management terminal.
  • S508 The application layer of the terminal sends the numbers of all other group members to the V2X layer of the terminal.
  • the V2X layer of the terminal receives the numbers of all other group members sent by the application layer of the terminal.
  • the V2X layer of the terminal sends the numbers of all other group members to the AS of the terminal.
  • the AS of the terminal receives the numbers of all other group members sent by the V2X layer of the terminal.
  • steps S501-S503 can be performed first, and then steps S507-S509; or, steps S507-S509 can be performed first, and then steps S501-S503 can be performed, or steps S501-S503, and S507-S509 can be performed simultaneously.
  • the application layer of the terminal can send the application layer identification of the group to the V2X layer of the terminal; after that, the V2X layer of the terminal generates/ The layer 2 identification of the group is allocated, and the layer 2 identification of the group is sent to the AS of the terminal.
  • the AS of the terminal knows the layer 2 identification of the group. Therefore, the multicast message sent by the AS of the terminal may include the layer 2 identifier of the group to indicate the group corresponding to the multicast message.
  • the application layer of the terminal also sends the third group to the V2X layer of the terminal.
  • the V2X layer of the terminal generates/assigns the layer 2 identifier of the third group member according to the application layer identifier of the third group member; then, the V2X layer of the terminal sends the layer 2 identifier of the third group to the AS of the terminal.
  • the AS of the terminal knows the layer 2 identification of the third group member. Therefore, when the AS of the terminal sends the multicast message, the layer 2 identifier of the third group member can be used as the source address in the multicast message.
  • the following uses the embodiment shown in FIG. 12 to specifically describe the function of the number of the group members corresponding to the terminal.
  • a communication method provided in an embodiment of this application includes the following steps:
  • the AS of the multicast receiving end receives the multicast message sent by the AS of the multicast sending end.
  • the multicast message may include the group identifier.
  • the multicast receiving end may be the first terminal/second terminal in the embodiment shown in FIG. 4 or FIG. 5, or the terminal in the embodiment shown in FIG. 9, FIG. 10, or FIG. 11.
  • the multicast receiver corresponds to the fourth member of the group. It is understandable that if the multicast receiving end is the first terminal in the embodiment shown in FIG. 4 or FIG. 5, the fourth group member is the first group member. If the multicast receiving end is the second terminal in the embodiment shown in FIG. 4 or FIG. 5, the fourth group member is the second group member. If the multicast receiving end is the terminal in the embodiment shown in FIG. 9, FIG. 10, or FIG. 11, the fourth group member is the third group member.
  • the AS at the multicast receiving end determines the feedback resource according to the number of the fourth group member.
  • the feedback resource is used to carry the ACK/NACK message of the multicast message.
  • the feedback resources include time domain resources, frequency domain resources, space domain resources, and/or code domain resources.
  • the time domain resource includes one or more time units, and the time unit may be a subframe, a time slot, an orthogonal frequency division multiplexing (OFDM) symbol, and the like.
  • the time unit may be a subframe, a time slot, an orthogonal frequency division multiplexing (OFDM) symbol, and the like.
  • the frequency domain resources include one or more frequency domain units, and the frequency domain units may be subcarriers and bandwidths.
  • Airspace resources include beams and antenna ports.
  • the code domain resource may be a symbol sequence that does not affect each other in the same time domain and frequency domain.
  • the number of the group member is used to determine the feedback resource corresponding to the group member.
  • the number of the group member and the feedback resource which specifically refers to the correspondence between the number of the group member and the index/name/identification/serial number of the feedback resource.
  • Table 5 is an example of the correspondence between the numbers of group members and the indexes of feedback resources. Taking an example with Table 5, suppose the number of the fourth group member is 2, so that the AS of the terminal sends an ACK/NACK message on the feedback resource whose index is 2.
  • the correspondence between the number of the group member and the feedback resource can exist implicitly.
  • the group member with the number 0 corresponds to the first feedback resource
  • the group member with the number 1 corresponds to the second feedback resource.
  • the correspondence between the number of the group member and the feedback resource may be explicit.
  • the multicast sending end may send the correspondence between the member numbers and feedback resources to the multicast receiving end in a broadcast/multicast manner.
  • the AS at the multicast receiving end sends an ACK/NACK message of the multicast message according to the feedback resource.
  • the AS of the multicast receiver When the AS of the multicast receiver receives the complete multicast message, the AS of the multicast receiver sends the ACK message of the multicast message according to the feedback resources, so that the AS of the multicast sender knows that the AS of the multicast receiver has completely received it Multicast messages.
  • the AS of the multicast receiver When the AS of the multicast receiver does not receive the multicast message or receives an incomplete multicast message, the AS of the multicast receiver sends the NACK message of the multicast message according to the feedback resources to trigger the AS of the multicast sender to resend the group Broadcast news.
  • the AS at the multicast receiving end determines the corresponding feedback resources according to the number of the group member corresponding to the multicast receiving, thereby ensuring that the AS at the multicast receiving end can normally send to the multicast sender ACK/NACK messages are fed back.
  • the multicast sender does not need to configure corresponding feedback resources for each of the reachable members one by one, which is beneficial to save signaling overhead and also reduces the complexity of implementing the multicast process.
  • the AS of the multicast sending end stores the correspondence between the numbers of the group members and the feedback resources. Therefore, the AS of the multicast sender can determine the number of the group member who feeds back the ACK/NACK message according to the index of the feedback resource where the received ACK/NACK message is located. Correspondingly, the AS of the multicast sender may also determine the number of the group member who has not fed back the ACK/NACK message according to the index of the feedback resource for which the ACK/NACK message is not transmitted.
  • the AS of the multicast sender may unicast the content of the multicast message to the group members who have not fed back the ACK/NACK message according to the numbers of the members who have not fed back the ACK/NACK message.
  • the AS at the multicast sending end or the AS at the multicast receiving end can obtain the numbers of the group members. Refer to the embodiments shown in FIG. 5, FIG. 9-10, and FIG. 14-17.
  • the number of reachable group members acquired by the terminal may be a number generated before, rather than a number regenerated every time it is acquired. For example, a group with a group of 20 members will generate group member numbers 1, 2, 3, ..., 20. If the terminal finds 5 reachable members, the previous numbers of the 5 reachable members in the group are 1, 5, 7, 13, and 18. Then the terminal can determine that the numbers of the 5 reachable members are 1,5,7,13,18, instead of redistributing the numbers 1,2,3,4,5 for the 5 reachable members.
  • the number of reachable group members acquired by the terminal may be a number that is regenerated each time it is acquired.
  • a group with a group size of 20 generates group member numbers 1, 2, 3, ..., 20. If the terminal finds 5 reachable members, the previous numbers of the 5 reachable members in the group are 1, 5, 7, 13, and 18. The terminal can reassign numbers 1, 2, 3, 4, and 5 to the 5 reachable members. Therefore, the terminal can determine that the numbers of the 5 reachable members are 1, 2, 3, 4, and 5.
  • the terminal includes hardware structures and/or software modules corresponding to each function.
  • the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed by hardware or computer software-driven hardware depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.
  • the embodiment of the present application may divide the terminal into functional modules according to the foregoing method examples.
  • each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module.
  • the above-mentioned integrated modules can be implemented in the form of hardware or software functional modules. It should be noted that the division of modules in the embodiments of the present application is illustrative, and is only a logical function division, and there may be other division methods in actual implementation. The following is an example of dividing each function module corresponding to each function:
  • FIG. 13 is a schematic structural diagram of a communication device provided by an embodiment of this application.
  • the communication device includes: an application layer module 1301, a V2X module 1302, and an AS module 1303.
  • the application layer module 1301 can be used to support the communication device to perform step S301 in FIG. 9, step S401 in FIG. 10, steps S501, S502, S504, and S505 in FIG. 5, and/or to support the technology described herein Other processes of the program.
  • the V2X layer module 1302 can be used to support the communication device to perform steps S101-S109 in Figure 4, steps S201-S205 in Figure 5, steps S301-S305 in Figure 9, steps S401 and S402 in Figure 10, and steps S401 and S402 in Figure 11 Steps S502, S503, S505, and S506, and/or other processes used to support the technical solutions described herein.
  • the AS module 1303 can be used to support the communication device to perform steps S106 or S109 in Figure 4, steps S202 or S204 in Figure 5, steps S303 and S305 in Figure 9, steps S402-S404 in Figure 10, and steps S402-S404 in Figure 11 Steps S503 and S506, S601-S603 in FIG. 12, and/or other processes used to support the technical solutions described herein.
  • the embodiment of the present application also provides a computer-readable storage medium on which an instruction is stored, and the method in the foregoing method embodiment is executed when the instruction is executed.
  • the embodiment of the present application also provides a computer program product containing instructions, which execute the method in the above method embodiment when the instruction is executed.
  • the embodiment of the present application further provides a chip system.
  • the chip system includes a processor for implementing the technical method in the embodiment of the present invention.
  • the chip system further includes a memory for storing necessary program instructions and/or data of the communication device in the embodiment of the present invention.
  • the chip system further includes a memory for the processor to call application program codes stored in the memory.
  • the chip system may be composed of one or more chips, and may also include chips and other discrete devices, which are not specifically limited in the embodiment of the present application.
  • An embodiment of the present application also provides a communication system, which includes a first terminal and a second terminal.
  • the first terminal is used to execute the communication method shown in FIG. 4 or FIG. 5.
  • the second terminal is used to execute the communication method shown in FIG. 4 or FIG. 5.
  • the steps of the method or algorithm described in conjunction with the disclosure of this application can be implemented in a hardware manner, or implemented in a manner in which a processor executes software instructions.
  • Software instructions can be composed of corresponding software modules, which can be stored in RAM, flash memory, ROM, erasable programmable read-only memory (erasable programmable ROM, EPROM), electrically erasable programmable read-only memory (electrically erasable programmable read-only memory, EPROM, EEPROM), registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium known in the art.
  • An exemplary storage medium is coupled to the processor, so that the processor can read information from the storage medium and can write information to the storage medium.
  • the storage medium may also be an integral part of the processor.
  • the processor and the storage medium may be located in the ASIC.
  • the ASIC may be located in the core network interface device.
  • the processor and the storage medium may also exist as discrete components in the core network interface device.
  • the memory may be coupled with the processor.
  • the memory may exist independently and be connected to the processor through a bus.
  • the memory can also be integrated with the processor.
  • the memory may be used to store application program codes for executing the technical solutions provided in the embodiments of the present application, and the processor controls the execution.
  • the processor is used to execute the application program code stored in the memory, so as to implement the technical solutions provided in the embodiments of the present application.
  • the disclosed device and method may be implemented in other ways.
  • the device embodiments described above are merely illustrative.
  • the division of the modules or units is only a logical function division.
  • there may be other division methods for example, multiple units or components may be It can be combined or integrated into another device, or some features can be omitted or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate parts may or may not be physically separate.
  • the parts displayed as units may be one physical unit or multiple physical units, that is, they may be located in one place, or they may be distributed to multiple different places. . Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.
  • each unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the above-mentioned integrated unit can be implemented in the form of hardware or software functional unit.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium.
  • the technical solutions of the embodiments of the present application are essentially or the part that contributes to the prior art, or all or part of the technical solutions can be embodied in the form of software products, which are stored in a storage medium.
  • a device which may be a single-chip microcomputer, a chip, etc.
  • a processor processor
  • the aforementioned storage media include: U disk, mobile hard disk, ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

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Abstract

本申请提供一种通信方法及装置，涉及通信装置，用于使终端的AS能够确定终端的周边的组员的具体数目，以使得终端的AS能够正常执行组播的HARQ机制。该方法包括：第一终端的V2X层发送第一消息，该第一消息包括群组的标识，该第一终端对应群组中的第一组员；之后，第一终端的V2X层接收第一消息的响应消息，并根据响应消息，确定群组中可达组员的个数；第一终端的V2X层向第一终端的AS发送可达组员的个数。

Description

通信方法及装置
本申请要求于2019年06月17日提交国家知识产权局、申请号为201910523810.8、申请名称为“通信方法及装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，尤其涉及通信方法及装置。
背景技术
车联网(vehicle to everything，V2X)技术是未来智能交通运输***的关键技术。它使得车与车、车与基站之间能够通信，使得车辆能够获取实时路况、道路信息、行人信息等一切交通信息，从而能够有效提高汽车驾驶的安全性、减少拥堵、提高交通效率、提供车载娱乐信息等。
V2X网络除了可以采用基于PC5接口的广播模式传输数据之外，还可以采用组播模式传输数据。目前，对于组播模式，发送端向群组中的组员发送组播信息，位于该发送端周边的组员在接收到该发送端发送的组播信息之后向发送端发送应答(acknowledgement，ACK)消息以表明成功接收到该组播信息，进而发送端根据接收到的ACK消息，确定是否所有位于该发送端周边的组员均成功接收到该组播信息。若发送端确定周边的组员中存在至少一个组员未成功接收到该组播信息，发送端可以重新发送组播信息，以实现组播的混合自动重传请求(hybrid automatic repeat request，HARQ)机制。
当前，在以终端的接入层(access stratum，AS)层执行组播的HARQ机制时，终端的AS不能够确定是否所有位于该终端周边的组员均成功接收到组播信息。这样一来，终端的AS无法正常执行组播的HARQ机制。
发明内容
本申请提供一种通信方法及装置，用于使终端的AS能够确定群组中位于终端周边的组员的具体数目，以使得终端的AS能够正常执行组播的HARQ机制。
第一方面，提供一种通信方法，包括：第一终端的V2X层发送第一消息，第一消息包括群组的标识，第一终端对应该群组中的第一组员；第一终端的V2X层接收第一消息的响应消息；第一终端的V2X层根据响应消息，确定群组中可达组员的个数；第一终端的V2X层向第一终端的AS发送可达组员的个数。
基于上述技术方案，第一终端的V2X层发送第一消息，以触发群组中的其他组员对应的终端反馈响应消息，从而第一终端的V2X层根据响应消息，能够发现群组中第一组员周边的组员，从而确定可达组员的个数。第一终端的V2X层向第一终端的AS发送可达组员的个数，从而使得第一终端的AS能够感知获知第一终端周边的组员的具体个数。这样一来，第一终端的AS能够根据接收到的ACK消息的个数是否等于感知到的第一终端周边的组员的具体个数，确定是否所有位于该第一终端周边的组员均成功接收到组播信息，从而保证第一终端的AS正常执行组播的HARQ机制。
一种可能的设计中，该方法还包括：第一终端的V2X层获得第一组员的编号，并向第一终端的AS发送第一组员的编号。其中，第一组员的编号用于确定第一组员对应的反馈资源。
一种可能的设计中，第一组员是群组中的可达组员中的一个。第一终端的V2X层获得第一组员的编号，包括：第一终端的V2X层根据可达组员的应用层标识的大小，确定第一组员的编号；或者，第一终端的V2X层根据可达组员的层2标识的大小，确定第一组员的编号；或者，第一终端的V2X层分配第一组员的编号。
一种可能的设计中，第一组员的编号为第一组员的层2标识或者第一组员的层1标识。
一种可能的设计中，该方法包括：第一终端的AS接收组播消息；第一终端的AS根据第一组员的编号，确定反馈资源；第一终端的AS根据反馈资源，发送组播消息的ACK/否认应答(negative acknowledgement，NACK)消息。基于该设计，一方面，第一终端的AS根据第一组员的编号，确定相应的反馈资源，从而保证了第一终端的AS可以正常地向组播发送端反馈ACK/NACK消息。另一方面，组播发送端无需针对可达组员中的每一个组员逐一配置相应的反馈资源，从而有利于节省信令开销，也减少了组播流程的实现复杂度。
一种可能的设计中，上述第一消息的响应消息包括群组的标识以及群组中第二组员的标识，第二组员为群组中的可达组员的一个。
一种可能的设计中，该方法还包括：第一终端的V2X层向第二组员对应的第二终端发送第二消息，第二消息携带有可达组员的个数或可达组员的标识中的至少一种。
一种可能的设计中，第二消息包括以下任意一种：可达组员的编号；或者，第二组员的编号；或者，可达组员中除第一组员之外其他所有组员的编号。
一种可能的设计中，第二消息还包括群组的标识。
第二方面，提供一种通信方法，包括：第二终端的V2X层接收来自第一终端的第一消息，第一消息包括群组的标识，第一终端对应群组中的第一组员，第二终端对应群组中的第二组员；第二终端的V2X层向第一终端发送第一消息的响应消息；第二终端的V2X层接收来自第一终端的第二消息；第二终端的V2X层根据第二消息，获得群组中的可达组员的个数；第二终端的V2X层向第二终端的AS发送可达组员的个数。
基于上述技术方案，第二终端的V2X层接收来自第一终端的第一消息，并向第一终端发送第一消息的响应消息，以使得第一终端的能够发现第二终端对应的第二组员是该第一终端对应的第一组员的周边组员。第二终端的V2X层接收来自第一终端的第二消息，获得可达组员的个数。第二终端的V2X层向第二终端的AS发送可达组员的个数，从而使得第二终端的AS能够感知获知第二终端周边的组员的具体个数。这样一来，第二终端的AS能够根据接收到的ACK消息的个数是否等于感知到的第二终端周边的组员的具体个数，确定是否所有位于该第二终端周边的组员均成功接收到组播信息，从而保证第二终端的AS正常执行组播的HARQ机制。
一种可能的设计中，响应消息包括群组的标识以及第二组员的标识。
一种可能的设计中，第二消息携带有可达组员的个数或可达组员的标识中的至少一种。
一种可能的设计中，第二消息包括以下任意一种：可达组员的编号；或者，第二组员的编号；或者，可达组员中除第一组员之外其他所有组员的编号。
一种可能的设计中，当所述第二消息包括所述第二组员的编号时，该方法还包括：第二终端的V2X层根据第二消息，获得第二组员的编号；第二终端的V2X层向第二终端的AS发送第二组员的编号。
一种可能的设计中，该方法还包括：第二终端的AS接收组播消息；第二终端的AS根据第二组员的编号，确定反馈资源；第二终端的AS根据反馈资源，发送组播消息的ACK/NACK消息。基于该设计，一方面，第二终端的AS根据第二组员的编号，确定相应的反馈资源，从而保证了第二终端的AS可以正常地向组播发送端反馈ACK/NACK消息。另一方面，组播发送端无需针对可达组员中的每一个组员逐一配置相应的反馈资源，从而有利于节省信令开销，也减少了组播流程的实现复杂度。
一种可能的设计中，第二消息包括群组的标识。
第三方面，提供一种通信方法，包括：终端的应用层向终端的V2X层发送群组中可达组员的应用层标识，终端对应群组中的第三组员；终端的V2X层根据可达组员的应用层标识，确定可达组员的个数；终端的V2X层向终端的AS发送可达组员的个数。
基于上述技术方案，终端的AS能够获知可达组员的个数，从而感知获知终端周边的组员的具体个数。这样一来，终端的AS能够根据接收到的ACK消息的个数是否等于感知到的终端周边的组员的具体个数，确定是否所有位于该终端周边的组员均成功接收到组播信息，从而保证终端的AS正常执行组播的HARQ机制。
一种可能的设计中，终端的V2X层根据可达组员的应用层标识，确定可达组员的个数，包括：终端的V2X层根据可达组员的应用层标识，生成/分配可达组员的层2标识；终端的V2X层根据可达组员的层2标识，确定可达组员的个数。
一种可能的设计中，方法还包括：终端的V2X层获得第三组员的编号；终端的V2X层向终端的AS发送第三组员的编号。其中，第三组员的编号用于确定第三组员的反馈资源。
一种可能的设计中，第三组员是群组中的可达组员中的一个；终端的V2X层获得第三组员的编号，包括：终端的V2X层根据可达组员的应用层标识的大小，确定第三组员的编号；或者，终端的V2X层根据可达组员的层2标识的大小，确定第三组员的编号；或者，终端的V2X层根据第一列表中第三组员所处的位置，确定第三组员的编号，第一列表用于记录可达组员的应用层标识或层2标识；或者，终端的V2X层根据第二列表，确定第三组员的编号，第二列表用于记录可达组员的层2标识；或者，终端的V2X层分配第三组员的编号。
一种可能的设计中，第三组员的编号为第三组员的层2标识或者第三组员的层1标识。
一种可能的设计中，该方法还包括：终端的AS接收组播消息；终端的AS根据第三组员的编号，确定反馈资源；终端的AS根据反馈资源，发送组播消息的ACK/NACK消息。基于该设计，一方面，终端的AS根据第三组员的编号，确定相应的反馈资源，从而保证了终端的AS可以正常地向组播发送端反馈ACK/NACK消息。另一方面，组播发送端无需针对可达组员中的每一个组员逐一配置相应的反馈资源，从而有利于节 省信令开销，也减少了组播流程的实现复杂度。
一种可能的设计中，方法还包括：终端的应用层向终端的V2X层发送群组的应用层标识；终端的V2X层根据群组的应用层标识，向终端的AS发送群组的层2标识。
第四方面，提供一种通信方法，包括：终端的应用层向终端的V2X层发送群组中可达组员的应用层标识，终端对应群组中的第三组员；终端的V2X层根据可达组员的应用层标识，向终端的AS发送可达组员的层2标识；终端的AS根据可达组员的层2标识，确定可达组员的个数。
基于上述技术方案，终端的AS能够获知可达组员的个数，从而感知获知终端周边的组员的具体个数。这样一来，终端的AS能够根据接收到的ACK消息的个数是否等于感知到的终端周边的组员的具体个数，确定是否所有位于该终端周边的组员均成功接收到组播信息，从而保证终端的AS正常执行组播的HARQ机制。
一种可能的设计中，该方法还包括：终端的AS获得第三组员的编号。其中，第三组员的编号用于确定第三组员的反馈资源。
一种可能的设计中，第三组员为群组中的可达组员中的一个；终端的AS获得第三组员的编号，包括：终端的AS根据可达组员的层2标识的大小，确定第三组员的编号；或者，终端的AS根据第二列表中第三组员所处的位置，确定第三组员的编号，第二列表用于记录可达组员的层2标识；或者，终端的AS分配第三组员的编号。
一种可能的设计中，第三组员的编号为第三组员的层2标识或者第三组员的层1标识。
一种可能的设计中，该方法还包括：终端的AS接收组播消息；终端的AS根据第三组员的编号，确定反馈资源；终端的AS根据反馈资源，发送组播消息的ACK/NACK消息。基于该设计，一方面，终端的AS根据第三组员的编号，确定相应的反馈资源，从而保证了终端的AS可以正常地向组播发送端反馈ACK/NACK消息。另一方面，组播发送端无需针对可达组员中的每一个组员逐一配置相应的反馈资源，从而有利于节省信令开销，也减少了组播流程的实现复杂度。
一种可能的设计中，该方法还包括：终端的应用层向终端的V2X层发送群组的应用层标识；终端的V2X层根据群组的应用层标识，向终端的AS发送群组的层2标识。
第五方面，提供一种通信方法，包括：终端的应用层获得群组中可达组员的个数，第三组员是群组中的一个可达组员；终端的应用层向终端的V2X层发送可达组员的个数；终端的V2X层向终端的AS发送可达组员的个数。
基于上述技术方案，终端的AS能够获知可达组员的个数，从而感知获知终端周边的组员的具体个数。这样一来，终端的AS能够根据接收到的ACK消息的个数是否等于感知到的终端周边的组员的具体个数，确定是否所有位于该终端周边的组员均成功接收到组播信息，从而保证终端的AS正常执行组播的HARQ机制。
一种可能的设计中，终端的应用层获得群组中可达组员的个数，包括：终端的应用层获取可达组员的应用层标识，并根据可达组员的应用层标识，确定可达组员的个数；或者，终端的应用层接收应用服务器发送的可达组员的个数；或者，终端的应用层接收群组管理终端发送的可达组员的个数。
一种可能的设计中，终端的应用层获取可达组员的应用层标识，包括：终端的应 用层接收应用服务器发送的可达组员的应用层标识；或者，终端的应用层接收群组管理终端发送的可达组员的应用层标识。
一种可能的设计中，该方法还包括：终端的应用层获得第三组员的编号；终端的应用层向终端的V2X层发送第三组员的编号；终端的V2X层向终端的AS发送第三组员的编号。其中，第三组员的编号用于确定第三组员的反馈资源。
一种可能的设计中，第三组员为群组中的可达组员中的一个；终端的应用层获得第三组员的编号，包括：终端的应用层根据可达组员的应用层标识的大小，确定第三组员的编号；或者，终端的应用层根据第三列表中第三组员所处的位置，确定第三组员的编号，第三列表用于记录可达组员的应用层标识；或者，终端的应用层分配第三组员的编号；或者，终端的应用层接收应用服务器发送的第三组员的编号；或者，终端的应用层接收群组管理终端发送的第三组员的编号。
一种可能的设计中，方法还包括：终端的AS接收组播消息；终端的AS根据第三组员的编号，确定反馈资源；终端的AS根据反馈资源，发送组播消息的ACK/NACK消息。基于该设计，一方面，终端的AS根据第三组员的编号，确定相应的反馈资源，从而保证了终端的AS可以正常地向组播发送端反馈ACK/NACK消息。另一方面，组播发送端无需针对可达组员中的每一个组员逐一配置相应的反馈资源，从而有利于节省信令开销，也减少了组播流程的实现复杂度。
一种可能的设计中，方法还包括：终端的应用层向终端的V2X层发送群组的应用层标识；终端的V2X层根据群组的应用层标识，向终端的AS发送群组的层2标识。
第六方面，提供一种通信装置，包括：V2X层模块和AS模块。V2X层模块，用于发送第一消息，第一消息包括群组的标识，通信装置对应群组的第一组员；接收第一消息的响应消息；根据响应消息，确定群组中可达组员的个数；向AS模块发送可达组员的个数。AS模块，用于接收V2X层模块发送的可达组员的个数。
一种可能的设计中，V2X层模块，还用于获得第一组员的编号，并向AS模块发送第一组员的编号。
一种可能的设计中，第一组员为群组中的可达组员中的一个；V2X层模块，还用于获得第一组员的编号，包括：根据可达组员的应用层标识的大小，确定第一组员的编号；或者，根据可达组员的层2标识的大小，确定第一组员的编号；或者，分配第一组员的编号。
一种可能的设计中，第一组员的编号为第一组员的层2标识或者第一组员的层1标识。
一种可能的设计中，AS模块，还用于接收组播消息；根据第一组员的编号，确定反馈资源；根据反馈资源，发送组播消息的ACK/NACK消息。
一种可能的设计中，响应消息包括群组的标识以及群组中第二组员的标识，第二组员为群组中的可达组员中的一个。
一种可能的设计中，V2X层模块，还用于向第二组员对应的第二终端发送第二消息，第二消息携带有可达组员的个数或可达组员的标识中的至少一种。
一种可能的设计中，第二消息包括以下任意一种：可达组员的编号；或者，第二组员的编号；或者，可达组员中除第一组员之外其他所有组员的编号。
一种可能的设计中，第二消息还包括群组的标识。
第七方面，提供一种通信装置，包括：V2X层模块和AS模块。V2X层模块，用于接收来自第一终端的第一消息，第一消息包括群组的标识，第一终端对应群组中的第一组员，通信装置对应群组中的第二组员；向第一终端发送第一消息的响应消息；接收第一终端的V2X层发送的第二消息；根据第二消息，获得可达组员的个数；向AS模块发送可达组员的个数。AS模块，用于接收V2X层模块发送的可达组员的个数。
一种可能的设计中，响应消息包括群组的标识以及第二组员的标识。
一种可能的设计中，第二消息携带有可达组员的个数或可达组员的标识中的至少一种。
一种可能的设计中，第二消息包括以下任意一种：可达组员的编号；或者，第二组员的编号；或者，可达组员中除第一组员之外其他所有组员的编号。
一种可能的设计中，V2X层模块，还用于根据第二消息，获得第二组员的编号；向AS模块发送第二组员的编号。AS模块，还用于接收V2X层模块发送的第二组员的编号。
一种可能的设计中，AS模块，还用于接收组播消息；根据第二组员的编号，确定反馈资源；根据反馈资源，发送组播消息的ACK/NACK消息。
一种可能的设计中，第二消息包括群组的标识。
第八方面，提供一种通信装置，包括：应用层模块、V2X层模块、以及AS模块。应用层模块，用于向V2X层模块发送群组中可达组员的应用层标识，通信装置对应群组中的第三组员。V2X层模块，用于接收V2X层模块发送的可达组员的应用层标识；根据可达组员的应用层标识，确定可达组员的个数；向AS模块发送群组中的可达组员的个数。AS模块，用于接收V2X层模块发送的可达组员的个数。
一种可能的设计中，V2X层模块，用于根据可达组员的应用层标识，确定可达组员的个数，包括：根据可达组员的应用层标识，生成/分配可达组员的层2标识；根据可达组员的层2标识，确定可达组员的个数。
一种可能的设计中，V2X层模块，还用于获得第三组员的编号；向AS模块发送第三组员的编号。AS模块，还用于接收V2X层模块发送的第三组员的编号。
一种可能的设计中，V2X层模块，还用于获得第三组员的编号，包括：根据可达组员的应用层标识的大小，确定第三组员的编号；或者，根据可达组员的层2标识的大小，确定第三组员的编号；或者，根据第一列表中第三组员所处的位置，确定第三组员的编号，第一列表用于记录可达组员的应用层标识或层2标识；或者，分配第三组员的编号。
一种可能的设计中，第三组员的编号为第三组员的层2标识或者第三组员的层1标识。
一种可能的设计中，AS模块，还用于接收组播消息；根据第三组员的编号，确定反馈资源；根据反馈资源，发送组播消息的ACK/NACK消息。
一种可能的设计中，应用层模块，还用于向V2X层模块发送群组的应用层标识。V2X层模块，还用于接收应用层模块发送的群组的应用层标识；根据群组的应用层标识，向AS模块发送群组的层2标识。AS模块，还用于接收V2X层模块发送的群组 的层2标识。
第九方面，提供一种通信装置，包括：应用层模块、V2X层模块和AS模块。应用层模块，用于向V2X层模块发送群组中可达组员的应用层标识，通信装置对应群组中的第三组员。V2X层模块，用于接收应用层模块发送的可达组员的应用层标识；根据可达组员的应用层标识，向AS模块发送可达组员的层2标识。AS模块，用于接收V2X层模块发送的可达组员的层2标识；根据可达组员的层2标识，确定可达组员的个数。
一种可能的设计中，AS模块，还用于获得第三组员的编号。
一种可能的设计中，AS模块，还用于获得第三组员的编号，包括：根据可达组员的层2标识的大小，确定第三组员的编号；或者，根据第二列表中第三组员所处的位置，确定第三组员的编号，第二列表用于记录可达组员的层2标识；或者，分配第三组员的编号。
一种可能的设计中，第三组员的编号为第三组员的层2标识或者第三组员的层1标识。
一种可能的设计中，AS模块，还用于接收组播消息；根据第三组员的编号，确定反馈资源；根据反馈资源，发送组播消息的ACK/NACK消息。
一种可能的设计中，应用层模块，还用于向V2X层模块发送群组的应用层标识。V2X层模块，还用于接收应用层模块发送的群组的应用层标识；根据群组的应用层标识，向AS模块发送群组的层2标识。AS模块，还用于接收V2X层模块发送的群组的层2标识。
第十方面，提供一种通信装置，包括：应用层模块、V2X层模块以及AS模块。应用层模块，用于获得群组中可达组员的个数，通信装置对应群组中的第三组员；向V2X层模块发送可达组员的个数。V2X层模块，用于向AS模块发送可达组员的个数。AS模块，用于接收V2X层模块发送的可达组员的个数。
一种可能的设计中，应用层模块，用于获得群组中可达组员的个数，包括：获取可达组员的应用层标识，并根据可达组员的应用层标识，确定可达组员的个数；或者，接收应用服务器/群组管理终端发送的可达组员的个数。
一种可能的设计中，应用层模块，用于获取可达组员的应用层标识，包括：接收应用服务器/群组管理终端发送的可达组员的应用层标识。
一种可能的设计中，应用层模块，还用于获得第三组员的编号；向V2X层模块发送第三组员的编号。V2X层模块，还用于向AS模块发送第三组员的编号。AS模块，还用于接收V2X层模块发送的第三组员的编号。
一种可能的设计中，应用层模块，还用于获得第三组员的编号，包括：根据可达组员的应用层标识的大小，确定第三组员的编号；或者，根据第三列表中第三组员所处的位置，确定第三组员的编号，第三列表用于记录可达组员的应用层标识；或者，分配第三组员的编号；或者，接收来自于应用服务器或群组管理终端的第三组员的编号。
一种可能的设计中，AS模块，还用于接收组播消息；根据第三组员的编号，确定反馈资源；根据反馈资源，发送组播消息的ACK/NACK消息。
一种可能的设计中，应用层模块，还用于向V2X层模块发送群组的应用层标识。V2X层模块，还用于接收应用层模块发送的群组的应用层标识；根据群组的应用层标识，向AS模块发送群组的层2标识。AS模块，还用于接收V2X层模块发送的群组的层2标识。
第十一方面，提供一种通信装置，包括：处理器和存储器，所述存储器和所述处理器耦合，所述处理器执行所述存储器中存储的指令时，可以实现上述第一方面至第五方面中任一方面所述的通信方法。可选的，该终端还可以包括通信接口，所述通信接口用于该通信装置与其它设备进行通信，示例性的，通信接口可以是收发器、电路、总线、模块或其它类型的通信接口。
第十二方面，提供一种计算机可读存储介质，该计算机可读存储介质中存储有指令，当其在计算机上运行时，可以使得计算机执行上述第一方面至第五方面中任一方面所涉及的通信方法。
第十三方面，提供一种计算机程序产品，所述计算机程序产品包括指令，当其在计算机上运行时，使得计算机可以执行上述第一方面至第五方面中任一方面所涉及的通信方法。
第十四方面，提供一种芯片，该芯片包括处理器，当该处理器执行指令时，处理器用于执行上述第一方面至第五方面中任一方面所涉及的通信方法。该指令可以来自芯片内部的存储器，也可以来自芯片外部的存储器。可选的，该芯片还包括输入输出电路。
第十五方面，提供一种通信***，包括第一终端和第二终端。其中，第一终端用于执行第一方面中任一种设计所涉及的通信方法。第二终端用于执行第二方面中任一种设计所涉及的通信方法。
上述第六方面至第十五方面中任一种设计的技术效果可以参考上文提供的对应方法中的有益效果，在此不再赘述。
附图说明
图1为本申请实施例提供的一种通信***的架构示意图；
图2为本申请实施例提供的一种终端的协议层的示意图；
图3为本申请实施例提供的一种通信装置的结构示意图；
图4为本申请实施例提供的一种通信方法的流程图；
图5为本申请实施例提供的另一种通信方法的流程图；
图6为本申请实施例提供的一种第二消息的示意图；
图7为本申请实施例提供的另一种第二消息的示意图；
图8为本申请实施例提供的另一种第二消息的示意图；
图9为本申请实施例提供的另一种通信方法的流程图；
图10为本申请实施例提供的另一种通信方法的流程图；
图11为本申请实施例提供的另一种通信方法的流程图；
图12为本申请实施例提供的另一种通信方法的流程图；
图13为本申请实施例提供的一种通信装置的结构示意图；
图14为本申请实施例提供的另一种通信方法的流程图；
图15为本申请实施例提供的另一种通信方法的流程图；
图16为本申请实施例提供的另一种通信方法的流程图；
图17为本申请实施例提供的另一种通信方法的流程图。
具体实施方式
在本申请的描述中，除非另有说明，“/”表示“或”的意思，例如，A/B可以表示A或B。本文中的“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。此外，“至少一个”是指一个或多个，“多个”是指两个或两个以上。“第一”、“第二”等字样并不对数量和执行次序进行限定，并且“第一”、“第二”等字样也并不限定一定不同。
需要说明的是，本申请中，“示例性的”或者“例如”等词用于表示作例子、例证或说明。本申请中被描述为“示例性的”或者“例如”的任何实施例或设计方案不应被解释为比其他实施例或设计方案更优选或更具优势。确切而言，使用“示例性的”或者“例如”等词旨在以具体方式呈现相关概念。
下面对本申请实施例所涉及的技术术语进行简单介绍。
1、HARQ
HARQ是前向纠错码(forward error correction，FEC)和自动重传请求(automatic repeat-request，ARQ)这两种技术的结合。采用HARQ机制时，在接收数据包的过程中，接收端使用FRC技术纠正能够纠正的错误数据包；并且，接收端通过错误检测判断不能纠正错误的数据包，丢弃该不能纠错的数据包，向发送端请求重新发送相同的数据包。
在本申请实施例中，组播模式下的HARQ机制主要是指：在一个群组中，当发送端组员发送组播消息时，该发送端组员周边的其他组员在成功接收到组播消息之后，其他组员向发送端组员发送响应消息(例如ACK消息或者NACK消息)，进而发送端组员根据接收到的响应消息确定是否周边的组员均成功接收到该组播消息。若发送端组员确定周边的组员中存在至少一个组员未成功接收到组播消息，发送端组员会重新发送组播消息。
2、群组、可达组员
群组可以是V2X应用中的一个群组，也可以是终端的应用层的组管理服务器所配置的一个群组。一个群组可以包括多个组员。
对于一个群组来说，可达组员可以包括该群组中的一部分组员或者全部组员。例如，群组包括组员#1、组员#2、组员#3、以及组员#4，所有可达组员包括组员#1和组员#2；或者，所有可达组员包括组员#1、组员#2、组员#3、以及组员#4。
对于群组中的一个组员来说，可达组员包括群组中能够接收到该组员发送的组播消息的其他组员。可选的，可达组员还包括该组员本身。举例来说，群组#1包括组员#1-组员#10，假设组员#2-组员#5位于组员#1的覆盖范围内，组员#6-组员#10位于组员#1的覆盖范围之外。也就是说，在组员#1发送组播消息的情况下，组员#2-组员#5能够接收到组员#1组播消息，组员#6-组员#10不能够接收到组员#1发送的组播消息。因此，对于组员#1来说，可达组员包括组员#2-组员#5。可选的，可达组员还包括组员#1。
或者，对于群组中的一个组员来说，可达组员包括群组中位于该组员周边的其他组员。可选的，可达组员还包括该组员本身。可以理解的是，群组中位于该组员周边的其他组员是指与该组员位于同一地理区域(例如街道、城市)的其他组员。或者，群组中位于该组员周边的其他组员是指与该组员位于同一通信区域(例如小区、跟踪区)的其他组员。举例来说，群组#1包括组员#1-组员#10，组员#1-组员#4位于小区#1，组员#5-组员#10位于小区#2。这种情况下，对于组员#1来说，可达组员包括组员#2和组员#3，还可以包括组员#1。对于组员#5来说，可达组员包括组员#6-组员#10，还可以包括组员#5。
3、终端对应的组员、组员对应的终端
对于一个群组来说，终端对应群组中的一个组员，具体是指：该终端的一个用户是该群组中的一个组员。例如，终端对应群组中的组员#1，则说明该终端的用户是群组中的组员#1。
对于一个群组来说，群组中的一个组员对应的终端，具体是指：作为该组员的用户所使用的终端。例如，用户#1是群组中的组员#1，组员#1对应的终端即为用户#1所使用的终端。
可选的，终端的用户可以是指终端的V2X应用的用户。
本申请实施例提供的方法可用于支持V2X业务数据传输的任一通信***，该通信***可以为第三代合作伙伴计划(3rd generation partnership project，3GPP)通信***，例如，长期演进(long term evolution，LTE)***，又可以为第五代(5th generation，5G)移动通信***或者新空口(new radio，NR)***，也可以为非3GPP通信***，不予限制。
如图1所示，提供了一种通信***的架构图，该通信***可以包括终端、接入网设备、核心网设备、数据网络(data network，DN)等。
终端，可以称为用户设备(user equipment，UE)或者终端设备(terminal)。该终端可以安装有V2X应用(application)。该终端可以支持V2X通信，如：接收或发送V2X消息，此时，该终端又可以称之为V2X终端。其中，V2X消息可以包括但不限于车辆对车辆(vehicle to vehicle，V2V)消息、车对人(vehicle to person，V2P)消息、车对网络(vehicle to network，V2N)消息、车与路面基础设施(vehicle to infrastructure，V2I)信息、车与车之间的防碰撞消息、娱乐应用消息、车与车之间交互的导航消息等。显然，图1所示终端可以包括但不限于车载终端、手机(mobile phone)、平板电脑或带无线收发功能的电脑、智能加油站、智能信号灯等等。
本申请实施例中，终端可以通过不同类型的通信接口传输V2X消息。其中，通信接口可以包括PC5口和/或Uu口。其中，Uu接口是终端和接入网设备之间的无线连接接口。PC5接口为终端之间用于V2X业务的用户面ProSe直接通信的参考点。
接入网设备，负责无线资源管理，上下行数据分类和QoS应用，以及与控制面网元完成信令处理，与用户面网元完成数据转发等功能。例如，接入网设备可以是基站，宽带网络业务网关(broadband network gateway，BNG)，汇聚交换机，非3GPP接入设备等。基站可以包括各种形式的基站，例如：宏基站，微基站(也称为小站)，中继站，接入点等，本申请实施例对此不作具体限定。对于终端接入核心网的设备，在 文中统一称之为接入网设备，不再进行说明。例如，接入网设备可以是4G网络中的演进型通用陆地无线接入网(evolved universal terrestrial radio access network，E-UTRAN)设备、5G网络中的下一代无线接入网(next generation radio access network，NG-RAN)设备等。
参见图1，核心网设备可以包括接入和移动性管理功能(access and mobility management function，AMF)、策略控制功能(policy control function，PCF)、统一数据管理(unified data management，UDM)、会话管理功能(session management function，SMF)、用户面功能(user plane function，UPF)、应用功能(application function，AF)、网络开发功能(network exposure function，NEF)、以及用户数据存储库(user data repository，UDR)。
AMF、PCF、UDM等网元的功能可以参考现有技术，在此不再赘述。
需要说明的是，除RAN之外的运营商网元构成的网络可以成为核心网，在4G网络中，其包括MME，S-GW，P-GW，HSS等网元，在5G网络中，其包括AMF，SMF，UPF，UDM，PCF等网元。
如图2所示，为一种终端的协议层的示意图，终端的协议层可以支持终端传输V2X消息。终端的协议层可以包括：应用层(application layer)、V2X层、AS。
其中，应用层，主要用于提供V2X服务，如：生成V2X消息。
V2X层，主要用于确定V2X消息的通信接口等、确定V2X消息在PC5接口的通信模式、PC5单播连接的建立、PC5通信的层2标识的确定。其中，终端的V2X层可以独立部署在终端中，也可以部署在终端的其他协议层中，如：可以部署在终端的非接入(non-access stratum，NAS)(图2中未示出)中。当V2X层部署在NAS中时，V2X层执行的动作可以认为是由NAS执行，不予限制。本申请实施例以终端的V2X层独立部署在终端中为例进行说明，不予限制。
AS，主要用于支持公共陆地移动网络(public land mobile network，PLMN)选择、小区选择、无资源资源管理等流程。示例性的，无线资源管理流程包括：无线资源控制(radio resource control，RRC)连接建立流程、终端和核心网之间的信令建立流程、切换流程等。对于PC5口通信，AS还为PC5接口发送的V2X消息申请PC5通信资源，为V2X消息填写源和目的层2地址，为PC5单播通信建立PC5-RRC连接等。
图3为本申请实施例提供的一种通信装置300的组成示意图，该通信装置300可以为终端或者终端中的芯片或者片上***。该通信装置300包括处理器301，通信线路302以及通信接口303。
进一步的，该通信装置300还可以包括存储器304。其中，处理器301，存储器304以及通信接口303之间可以通过通信线路302连接。
其中，处理器301可以是中央处理器(central processing unit，CPU)、通用处理器网络处理器(network processor，NP)、数字信号处理器(digital signal processing，DSP)、微处理器、微控制器、可编程逻辑器件(programmable logic device，PLD)或它们的任意组合。处理器301还可以是其它任意具有处理功能的装置，例如电路、器件或软件模块，不做限制。
通信线路302，用于在通信装置300所包括的各部件之间传送信息。
通信接口303，用于与其他设备或其它通信网络进行通信。该其它通信网络可以为以太网，无线接入网(radio access network，RAN)，无线局域网(wireless local area networks，WLAN)等。通信接口303可以是模块、电路、收发器或者任何能够实现通信的装置。
存储器304，用于存储指令。其中，指令可以是计算机程序。
其中，存储器304可以是只读存储器(read-only memory，ROM)或可存储静态信息和/或指令的其他类型的静态存储设备，也可以是存取存储器(random access memory，RAM)或者可存储信息和/或指令的其他类型的动态存储设备，还可以是电可擦可编程只读存储器(electrically erasable programmable read-only memory，EEPROM)、只读光盘(compact disc read-only memory，CD-ROM)或其他光盘存储、光碟存储(包括压缩光碟、激光碟、光碟、数字通用光碟、蓝光光碟等)、磁盘存储介质或者其他磁存储设备等，不予限制。
需要指出的是，存储器304可以独立于处理器301存在，也可以和处理器301集成在一起。存储器304可以用于存储指令或者程序代码或者一些数据等。存储器304可以位于通信装置300内，也可以位于通信装置300外，不做限制。
处理器301，用于执行存储器304中存储的指令，以实现本申请下述实施例提供的通信方法。例如，当通信装置300为终端或者终端中的芯片或者片上***时，处理器301可以执行存储器304中存储的指令，以实现本申请下述实施例中发送端所执行的步骤。
在一种示例中，处理器301可以包括一个或多个CPU，例如图3中的CPU0和CPU1。
作为一种可选的实现方式，通信装置300包括多个处理器，例如，除图3中的处理器301之外，还可以包括处理器307。
作为一种可选的实现方式，通信装置300还包括输出设备305和输入设备306。示例性地，输入设备306是键盘、鼠标、麦克风或操作杆等设备，输出设备305是显示屏、扬声器等设备。
下面结合说明书附图，对本申请实施例提供的技术方案进行具体介绍。
如图4所示，为本申请实施例提供的一种通信方法，该方法包括以下步骤：
S101、第一终端的V2X层发送第一消息。
其中，上述第一消息可以包括群组的标识。群组的标识可以包括：群组的应用层标识和/或层2标识。
可以理解的是，第一消息包括群组的标识，可以用于指示该第一消息所对应的群组。
其中，第一消息可以用于发现群组中除第一终端对应的第一组员之外的其他可达组员。或者说，第一消息可以用于发现群组中位于第一终端对应的第一组员周边的组员。可选的，第一消息还可以称为组成员报告(group member report)，本申请实施例不限于此。
其中，第一终端可以对应群组中的第一组员，该第一组员可以是该群组中的可达组员中的一个。
可选的，第一消息还包括：指示信息和第一组员的标识。该指示信息可以用于指 示反馈第一消息的响应消息。第一组员的标识可以包括第一组员的应用层标识和/或层标识。
作为一种实现方式，当第一终端的V2X应用触发组播业务时，第一终端的应用层向第一终端的V2X层发送业务触发的指示消息。之后，第一终端的V2X层以组播/广播的方式发送第一消息。
作为另一种实现方式，当第一终端的应用层建立/更新V2X群组时，第一终端的应用层向第一终端的V2X层发送V2X群组建立/更新的指示信息。之后，第一终端的V2X层以组播/广播的方式发送第一消息。
上述业务触发的指示信息、以及V2X群组建立/更新的指示信息均可以包括群组的应用层标识，还可以包括第一组员的应用层标识。
S102、第二终端的V2X层接收来自第一终端的第一消息。
其中，第二终端可以为该群组中除第一组员之外的任意一个组员(可以称之为第二组员)对应的终端。例如，若一个终端的V2X层能够接收到来自第一终端的第一消息，且该终端的用户是第一消息所对应的群组中的组员，则该终端即为第二终端。举例说明，终端#1的用户是群组#1中的组员，终端#2的用户是群组#2中的组员，终端#3的用户是群组#1中的组员，终端#4的用户是群组#1中的组员。假设终端#1为第一终端，终端#1的V2X层发送第一消息，该第一消息包括群组#1的标识。终端#2的V2X层、终端#3的V2X层、终端#4的V2X层均接收到来自终端#1的第一消息。由于终端#2的用户不是群组#1中的组员，因此第二终端不包括终端#2。终端#3的用户和终端#4的用户是群组#1中的组员，因此第二终端可以为终端#3和终端#4中的至少一个。
可以理解的是，由于第二终端的V2X层能够接收到来自于第一终端的第一消息，因此第二终端位于第一终端的周边，也就是说，第二终端对应的第二组员位于第一终端对应的第一组员的周边。这样一来，第二终端对应的第二组员也是所述群组中的可达组员中的一个。
S103、第二终端的V2X层发送第一消息的响应消息。
其中，上述响应消息可以包括：群组的标识和第二组员的标识。其中，第二组员的标识可以包括第二组员的应用层标识和/或层2标识。需要说明的是，上述响应消息所包括的群组的标识与第一消息所包括的群组的标识可以是同一个群组的标识。
上述响应消息可以有其他名称，例如，组成员报告响应(group member report ack)，本申请实施例不限于此。
作为一种实现方式，第二终端的V2X层从第二终端的应用层获取群组的应用层标识；并根据群组的应用层标识，生成/分配群组的层2标识。从而，第二终端的V2X层可以存储群组的标识。在第二终端的V2X层接收到第一消息之后，第二终端的V2X层判断自身存储的群组的标识是否匹配第一消息所包括的群组的标识。若自身存储的群组的标识与第一消息所包括的群组的标识相同，则第二终端的V2X层发送第一消息的响应消息。
其中，第二终端的V2X层根据群组的应用层标识，分配该群组的层2标识，具体是指：第二终端的V2X层随机分配一个该群组的层2标识。
第二终端的V2X层根据群组的应用层标识，生成该群组的层2标识，具体是指：第二终端的V2X层根据预设的算法/第一对应关系，以及群组的应用层标识，生成群组的层2标识。其中，第一对应关系是指群组的应用层标识与群组的层2标识之间的对应关系。示例性的，表1为第一对应关系的一个示例。结合表1进行举例说明，假设群组的应用层标识为11，则第二终端的V2X层能够确定群组的层2标识为1111110000000000。
表1
群组的应用层标识 群组的层2标识
11 1111110000000000
10 1111110000000001
00 1111110000000011
01 1111110000000010
S104、第一终端的V2X层接收第一消息的响应消息。
可以理解的是，第一终端的V2X层可能接收到一个或多个第一消息的响应消息。
S105、第一终端的V2X层根据响应消息，确定可达组员的个数。
作为一种实现方式，第一终端的V2X层根据接收到的响应消息的个数，确定可达组员的个数。
若上述第二组员是群组中的可达组员中的一个，且第一组员是群组中可达组员中的一个，则可达组员的个数可以等于接收到响应消息的个数加1。
结合步骤S102中的例子，假设终端#1仅接收到终端#3的响应消息，那么群组#1中可达组员的个数可以是2。
若第二组员是群组中的可达组员中的一个，且第一组员不是群组中可达组员中的一个，则可达组员的个数可以等于接收到的响应消息的个数。
结合步骤S102中的例子，假设终端#1接收到终端#3发送的响应消息以及终端#4发送的响应消息，则群组#1中可达组员的个数可以是2。
S106、第一终端的V2X层向第一终端的AS发送可达组员的个数。相应地，第一终端的AS接收到可达组员的个数。
从而，第一终端的AS能够获知群组中位于第一终端周边的组员的具体数目。具体的，在第一组员不是群组中可达组员中的一个的情况下，群组中位于第一终端周边的组员的个数等于可达组员的个数。在第一组员是群组中可达组员中的一个的情况下，群组中位于第一终端周边的组员的个数等于可达组员的个数减去1。
可选的，除了可达组员的个数之外，第一终端的V2X层还向第一终端的AS发送群组的层2标识和/或第一组员的层2标识。
基于步骤S101-S106，第一终端的V2X层通过发送第一消息，以触发群组中第一组员周边的组员发送第一消息的响应消息，从而第一终端的V2X层能够根据第一消息的响应消息，确定可达组员的个数。第一终端的V2X层向第一终端的AS发送可达组员的个数。这样一来，第一终端的AS可以根据可达组员的个数，确定群组中位于第一组员周边的组员的具体数目。这样一来，第一终端的AS在发起组播业务的情况下，第一终端的AS根据可达组员的个数以及接收到的ACK消息的个数，判断第一终端周 边的组员是否均成功接收到组播消息，以保证HARQ机制的正常执行。
可选地，图4所示的通信方法还包括步骤S107-S109，如下所述。
S107、第一终端的V2X层向第二终端的V2X层发送第二消息。
其中，第二消息可以用于使第二终端的V2X层获得可达组员的个数。第二消息可以携带有可达组员的个数和可达组员的标识中的至少一种。
其中，可达组员的标识可以包括：第一组员的标识以及所有第二组员的标识。
可选的，第二消息还包括群组的标识。另外，在第二消息不携带可达组员的标识的情况下，第二消息还可以包括第一组员的标识。
可选的，第二消息为组信息通知(group information notification)，本申请实施例不限于此。
作为一种实现方式，第一终端的V2X层以单播的方式发送第二消息。
作为另一种实现方式，第一终端的V2X层以组播/广播的方式发送第二消息。可以理解的是，相比于单播的方式，第二消息以组播/广播的方式发送，有利于节省信令开销。
需要说明的是，本申请实施例不限制第一终端的V2X层执行步骤S106和S107的顺序。例如，第一终端的V2X层可以先执行步骤S106，再执行步骤S107；或者，可以先执行步骤S107，再执行步骤S106；或者，同时执行步骤S106和S107。
S108、第二终端的V2X层根据第二消息，获得可达组员的个数。
在第二消息包括可达组员的个数的情况下，第二终端的V2X层通过解析第二消息，可以直接获取可达组员的个数。
在第二消息不包括可达组员的个数，但包括可达组员的标识的情况下，第二终端的V2X层通过解析第二消息，获取可达组员的标识；之后，第二终端的V2X层根据可达组员的标识，确定可达组员的个数。可以理解的是，可达组员的个数等于可达组员的标识的个数。
举例来说，若第二消息包括：可达组员#1的标识、可达组员#2的标识、可达组员#3的标识、以及可达组员#4的标识，则第二终端的V2X层能够确定可达组员的个数为4。
S109、第二终端的V2X层向第二终端的AS发送可达组员的个数。相应地，第二终端的AS获取到可达组员的个数。
可选的，除了可达组员的个数之外，第二终端的V2X层还向第二终端的AS发送群组的层2标识和/或第二组员的层2标识。
基于上述技术方案，第二终端的V2X层接收第一消息；在第二终端对应的第二组员属于第一消息对应的群组的情况下，第二终端的V2X层发送第一消息的响应消息，以使得第一终端获知第二终端对应的组员位于第一终端的周边。之后，第二终端的V2X层接收第二消息，并根据第二消息，获得可达组员的个数。第二终端的V2X层向第二终端的AS发送可达组员的个数。这样一来，第二终端的AS在发起组播业务的情况下，第二终端的AS根据可达组员的个数以及接收到的ACK消息的个数，判断第二终端周边的组员是否均成功接收到组播消息，以保证HARQ机制的正常执行。
可选的，如图5所示，提供了另一种通信方法，该方法是在图4所示的通信方法 的基础上实现的，具体地，在步骤S104之后，还包括步骤S201-S202。
S201、第一终端的V2X层获得第一组员的编号。
其中，第一组员的编号可以为第一组员的层2标识、层1标识、或者其他参数。
需要说明的是，层1标识可以是由层2标识经过截短处理得到。也就是说，层1标识是截短后的层2标识。举例来说，假设截短处理是指将层2标识的前10个比特截去，仅保留层2标识第11个比特之后的比特，若第一组员的层2标识为0011001111110001，则第一组员的层1标识为110001。
可选的，若第一组员是群组中可达组员中的一个，在第一组员的编号为其他参数的情况下，第一终端的V2X层可以采用以下实现方式中的任意一种，以获得第一组员的编号。
实现方式一、第一终端的V2X层根据可达组员的应用层标识的大小，确定第一组员的编号。
可选的，第一终端的V2X层将所有可达组员的应用层标识按照大小进行排序，并根据第一组员的应用层标识在第一排列顺序/第二排列顺序中的序号，作为第一组员的编号。其中，第一排列顺序是指所有可达组员的应用层标识从小到大的排列顺序。第二排列顺序是指所有可达组员的应用层标识从大到小的排列顺序。
示例性的，对于第一排列顺序或第二排列顺序来说，起始序号可以为任意一个自然数，例如0。
下面以举例的方式说明上述实现方式一。假设可达组员#1的应用层标识为0000，可达组员#2的应用层标识为0011，可达组员#3的应用层标识为0010，可达组员#4的应用层标识为0001，则第一排列顺序可以为：可达组员#1的应用层标识、可达组员#4的应用层标识、可达组员#3的应用层标识，可达组员#2的应用层标识。假设第一排列顺序的起始序号为0，因此，可达组员#1的应用层标识在第一排列顺序中的序号为0，可达组员#4的应用层标识在第一排列顺序中的序号为1，可达组员#3的应用层标识在第一排列顺序中的序号为2，可达组员#2的应用层标识在第一排列顺序中的序号为3。这样一来，若第一组员为可达组员#3，则第一终端的V2X层可以第一组员的编号为2。
实现方式二、第一终端的V2X层根据可达组员的层2标识的大小，确定第一组员的编号。
可选的，第一终端的V2X层将所有可达组员的层2标识按照大小进行排序，并根据第一组员的层2标识在第三排列顺序/第四排列顺序中的序号，作为第一组员的编号。其中，第三排列顺序是指所有可达组员的层2标识从小到大的排列顺序。第四排列顺序是指所有可达组员的层2标识从大到小的排列顺序。
示例性的，对于第三排列顺序或第四排列顺序来说，起始序号可以为任意一个自然数，例如0。
下面以举例的方式说明上述实现方式二。假设可达组员#1的层2标识为0011001111110000，可达组员#2的层2标识为0011001111110011，可达组员#3的层2标识为0011001111110010，可达组员#4的层2标识为0011001111110001，则第三排列顺序可以为：可达组员#1的层2标识、可达组员#4的层2标识、可达组员#3的层2标识，可达组员#2的层2标识。假设第三排列顺序的起始序号为0，因此，可达组员 #1的层2标识在第三排列顺序中的序号为0，可达组员#4的层2标识在第三排列顺序中的序号为1，可达组员#3的层2标识在第三排列顺序中的序号为2，可达组员#2的层2标识在第三排列顺序中的序号为3。这样一来，若第一组员为可达组员#3，第一终端的V2X层可以确定第一组员的编号为2。
实现方式三、第一终端的V2X层分配第一组员的编号。
其中，编号的取值范围是根据可达组员的个数来确定的。例如，可达组员的个数为10，则编号的取值可以从0至9的整数中选择，或者编号的取值可以从1至10的整数中选择。
需要说明的是，分配给第一组员的编号不会被分配给可达组员中的其他组员。也就是说，在群组中，可达组员中不同的两个组员具有不同的两个编号。
举例来说，假设群组中可达组员包括10个组员，则第一终端的V2X层需要分配10个编号，这10个编号可以分别为0,1,2,3,4,5,6,7,8,9。第一终端的V2X层可以从10个编号之中随机选择一个编号(例如编号9)分配给第一组员。
S202、第一终端的V2X层向第一终端的AS发送第一组员的编号。
需要说明的是，本申请实施例不限制步骤S201-S202与步骤S105-S106的执行顺序。也就是说，第一终端的V2X层可以先执行步骤S201-S202，再执行步骤S105-S106；或者，先执行步骤S105-S106，再执行步骤S201-S202；或者，同时执行步骤S105-S106，和步骤S201-S202。
可选的，在第一终端的V2X层同时执行步骤S202和步骤S106的情况下，第一组员的编号以及可达组员的个数可以承载于同一消息中。
基于步骤S201-S202，第一终端的AS能够获知第一组员的编号。从而，第一终端的AS在接收到组播消息之后，第一终端的AS能够根据第一组员的编号，确定相应的反馈资源，并根据反馈资源，发送组播消息的ACK/NACK消息。其具体细节可以参考下文图12所示的实施例。
可选的，如图14所示，提供了另一种通信方法，该通信方法是在图4所示的通信方法的基础上实现的，具体地，在步骤S104之后，该通信方法还包括步骤S206-S207。
S206、第一终端的V2X层获取可达组员中除第一组员之外的其他所有组员的编号。
其中，其他所有组员中每一个组员的编号可以是该组员的层2标识、层1标识或者其他参数。
可选的，若其他所有组员的编号为其他参数的情况下，第一终端的V2X层可以采用以下实现方式中的任意一种，以获得其他所有组员的编号。
实现方式一、第一终端的V2X层根据所有可达组员的应用层标识的大小，确定其他所有组员的编号。
实现方式二、第一终端的V2X层根据所有可达组员的层2标识的大小，确定其他所有组员的编号。
实现方式三、第一终端的V2X层分配其他所有组员的编号。
实现方式四、第一终端的V2X层根据响应消息，确定其他所有组员的编号。响应消息包括用于指示可达组员的编号的指示信息。
其中，上述实现方式一至实现方式三的具体细节可以参考步骤S201中的描述，在 此不再赘述。
S207、第一终端的V2X层向第一终端的AS发送所述其他所有组员的编号。
需要说明的是，本申请实施例不限制步骤S206-S202与步骤S105-S106的执行顺序。也就是说，第一终端的V2X层可以先执行步骤S201-S207，再执行步骤S105-S106；或者，先执行步骤S105-S106，再执行步骤S206-S207；或者，同时执行步骤S105-S106，和步骤S206-S207。
基于步骤S206-S207，第一终端的AS能够获知所有可达组员中除第一组员之外的其他所有组员的编号。
可选的，图5所示的实施例和图14所示的实施例可以一起执行，也可以各自单独执行，本申请对此不作限定。
可选的，如图5所示，图4所示的通信方法在步骤S107之后，还可以包括步骤S203-S204。
S203、第二终端的V2X层获得第二组员的编号。
其中，第二组员的编号可以为第二组员的层2标识、层1标识、或者其他参数。
在第二组员的编号为其他参数的情况下，第二终端的V2X层可以根据第二消息，获得第二组员的编号。
可选的，第二消息以隐式的方式指示第二组员的编号。例如，第二消息包括可达组员的标识。
这样一来，第二终端的V2X层可以从第二消息，获取可达组员的标识。之后，第二终端的V2X层根据可达组员的应用层标识/层2标识的大小，确定第二组员的编号。其中，第二组员的编号的确定方式可以参考步骤S201中实现方式一或实现方式二的相关描述。
或者，组员的标识在第二消息中的位置对应组员的编号。从而，第二终端的V2X层根据第二组员的标识在第二消息中的位置，确定第二组员的编号。
结合图6进行举例说明，组员#1的标识位于第二消息中的第一位置，组员#2的标识位于第二消息中的第二位置，组员#3的标识位于第二消息中的第三位置。第二消息中第一位置对应编号1，第二消息中的第二位置对应编号2，第二消息中的第三位置对应编号3。假设第二终端对应的第二组员为组员#3，则第二终端的V2X层能够确定第二组员的编号为3。
可选的，第二消息以显式的方式指示第二组员的编号。
例如，第二消息包括第二组员的编号。这样一来，第二终端的V2X层通过解析第二消息，可以直接获取到第二组员的编号。
需要说明的是，在第二消息仅包括第二组员的编号，不包括其他组员的编号的情况下，第一终端的V2X层是以单播的方式将该第二消息发送给第二终端的V2X层。
又例如，第二消息可以包括可达组员的编号。或者，在第一组员为群组中可达组员中的一个的情况下，第二消息还可以包括可达组员中除了第一组员之外的其他所有组员的编号。
下面以第二消息包括可达组员的编号的情况，具体说明第二终端的V2X层如何确定第二组员的编号。可以理解的是，在第二消息包括可达组员中除了第一组员之外的 其他所有组员的编号的情况下，第二终端的V2X层确定第二组员的编号的实现方式也可以参考下文中的相应描述。
第二消息包括可达组员的编号，还包括可达组员的标识。对于可达组员中的任一个组员来说，该组员的标识在第二消息中的位置，可以隐式指示该组员的编号在第二消息中的位置。从而，由于第二终端的V2X层预先获知第二组员的标识，因此第二终端的V2X层可以先确定第二组员的标识在第二消息中的位置，从而确定第二组员的编号在第二消息中的位置，进而确定第二组员的编号。
可选的，在第二消息包括可达组员的编号和可达组员的标识的情况下，组员的标识在第二消息中的位置隐式指示该组员的编号在第二消息中的位置，包括以下两种实现方式：
实现方式一、第二消息包括第一信元和第二信元，第一信元用于承载可达组员的标识，第二信元用于承载可达组员的编号。对于可达组员中的任一个组员来说，组员的标识在第一信元中的位置与组员的编号在第二信元中的位置相同。
基于实现方式一，第二终端的V2X层通过确定第二组员的标识在第一信元中的位置，从而确定第二组员的编号在第二信元中的位置。这样一来，第二终端的V2X层从第二信元中能够获取到第二组员的编号。
结合图7进行举例说明，如图7所示，组员#1的标识在第一信元中的第一位置，组员#2的标识在第一信元中的第二位置，组员#3的标识在第一信元中的第三位置。组员#1的编号在第二信元中的第一位置，组员#2的编号在第二信元中的第二位置，组员#3的编号在第二信元中的第三位置。假设第二组员为组员#3，第二终端的V2X层先确定组员#3的标识位于第一信元中的第三位置，从而第二终端的V2X层从第二信元的第三位置获取组员#3的编号。
实现方式二、第二消息包括M个信元，M等于可达组员的个数。M个信元中一个信元对应一个组员，一个信元用于承载对应的组员的标识和编号。
基于实现方式二，第二终端的V2X层通过确定第二信息中用于承载第二组员的标识的信元，从而在第二信息中用于承载第二组员的标识的信元中获取到第二组员的编号。
结合图8进行举例说明，组员#1的标识以及编号承载于第二消息的信元#1中，组员#2的标识以及编号承载于第二消息的信元#2中，组员#3的标识以及编号承载于第二消息的信元#3中。假设第二组员为组员#2，则第二终端的V2X层能够确定根据组员#2的标识，确定信元#2，并从信元#2中获得组员#2的编号。
S204、第二终端的V2X层向第二终端的AS发送第二组员的编号，以使得第二终端的AS接收到第二终端的V2X层发送的第二组员的编号。
需要说明的是，本申请实施例不限制步骤S203-S204和步骤S108-S109的执行顺序。也就是说，第二终端的V2X层可以先执行步骤S203-S204，再执行步骤S108-S109；或者，先执行步骤S108-S10，再执行步骤S203-S204；或者，同时执行步骤S203-S204，和步骤S108-S109。
可选的，在第二终端的V2X层同时执行步骤S204和步骤S109的情况下，第二组员的编号和可达组员的个数可以承载于同一消息中。
基于上述步骤S203-S204，第二终端的AS能够获知第二组员的编号。从而，第二终端的AS在接收到组播消息之后，第二终端的AS能够根据第二组员的编号，确定相应的反馈资源，并根据反馈资源，发送组播消息的ACK/NACK消息。其具体细节可以参考下文图12所示的实施例。
可选的，在第二消息包括第二组员的编号的情况下，如图5所示，该通信方法在步骤S107之前还包括步骤S205。
S205、第一终端的V2X层获得第二组员的编号。
其中，第一终端获得第二组员的编号的具体实现方式可以参考步骤S201中的相关描述，在此不再赘述。
需要说明的是，本申请实施例不限制步骤S201和步骤S205的执行顺序。
如图9所示，为本申请实施例提供的一种通信方法，该方法包括以下步骤：
S301、终端的应用层向终端的V2X层发送可达组员的应用层标识。相应地，终端的V2X层接收终端的应用层发送的可达组员的应用层标识。
在本申请实施例中，终端对应群组中的第三组员。第三组员可以是群组中可达组员中的一个。
可选的，终端的应用层执行步骤S301的触发条件包括但不限于：终端的V2X应用触发组播业务、群组的建立、群组的更新。
作为一种实现方式，终端的应用层获得群组中可达组员的应用层标识；之后，终端的应用层向终端的V2X层发送可达组员的应用层标识。
可选的，终端的应用层获得群组中可达组员的应用层标识，包括：终端的应用层接收其他设备(例如应用服务器或者群组管理终端)发送的可达组员的应用层标识。
其中，群组管理终端是用于管理群组的终端，具有创建群组、更新群组的组员、删除群组等功能。或者说，群组管理终端对应群组中的管理组员，该管理组员用于对群组进行管理，具有创建群组、更新群组的组员、删除群组等功能。
S302、终端的V2X层根据可达组员的应用层标识，获得可达组员的个数。
作为一种实现方式，终端的V2X层统计可达组员的应用层标识的个数，获得可达组员的个数。其中，可达组员的个数等于可达组员的应用层标识的个数。
例如，终端的V2X层接收到组员#1的应用层标识、组员#3的应用层标识、组员#5的应用层标识、组员#6的应用层标识、以及组员#7的应用层标识，则终端的V2X层能够确定可达组员的应用层标识的个数为5，从而终端的V2X层确定可达组员的个数为5。
作为另一种实现方式，终端的V2X层根据可达组员的应用层标识，生成/分配可达组员的层2标识；之后，终端的V2X层统计可达组员的层2标识的个数，获得可达组员的个数。其中，可达组员的个数等于可达组员的层2标识的个数。
其中，终端的V2X层根据可达组员的应用层标识，分配可达组员的层2标识，具体是指：终端的V2X层随机分配一个可达组员的层2标识。
终端的V2X层根据可达组员的应用层标识，生成可达组员的层2标识，具体是指：终端的V2X层根据预设的算法/第二对应关系，以及可达组员的应用层标识，生成可达组员的层2标识。其中，第二对应关系是指组员的应用层标识与组员的层2标识之 间的对应关系。示例性的，表2为第二对应关系的一个示例。结合表2进行举例说明，假设可达组员中的一个组员的应用层标识为1101，则终端的V2X层能够确定该组员的层2标识为111101011001001。假设可达组员中的一个组员的应用层标识为1111，则终端的V2X层能够确定该组员的层2标识为111101011001101。
表2
组员的应用层标识 组员的层2标识
1101 111101011001001
1110 111101011001010
1111 111101011001101
1100 111101111001001
S303、终端的V2X层向终端的AS发送可达组员的个数。相应地，终端的AS接收终端的V2X层发送的可达组员的个数。
基于上述步骤S301-S303，终端的AS层能够获知可达组员的个数，从而保证终端的AS能够在组播模式下执行HARQ机制。
可选的，如图9所示，该通信方法还包括步骤S304-S305。
S304、终端的V2X层获得第三组员的编号。
其中，第三组员的编号可以是第三组员的层2标识、层1标识或者其他参数。
可选的，在第三组员是群组中可达组员中的一个的情况下，若第三组员的编号为其他参数，则终端的V2X层可以根据以下实现方式中的任意一种，确定第三组员的编号。
实现方式一、终端的V2X层根据可达组员的应用层标识的大小，确定第三组员的编号。
实现方式二、终端的V2X层根据可达组员的层2标识的大小，确定第三组员的编号。
实现方式三、终端的V2X层分配第三组员的编号。
上述实现方式一至实现方式三的细节可以参考图5所示实施例中步骤S201的相关描述，在此不在赘述。
实现方式四、终端的V2X层根据第一列表中第三组员所处的位置，确定第三组员的编号。
其中，第一列表用于记录可达组员的应用层标识或层2标识。
可选的，终端的V2X层根据第三组员的应用层标识/层2标识在第一列表中的位置，确定第三组员的编号。例如，在第一列表以一列/行记录一个可达组员的应用层标识/层2标识的情况下，终端的V2X层可以以第三组员的应用层标识/层2标识所在的列/行的序号，作为第一可达组员的编号。
举例说明，假设第一列表用于记录可达组员的应用层标识，表3为第一列表的一个示例。假设第三组员的应用层标识为1101，可见第三组员的应用层标识在第一列表中的第一行。假设第一列表中的行从0开始排序时，第一行的序号为0。这样一来，终端的V2X层可以确定第三组员的编号为0。
表3
1101
1110
1111
1100
举例说明，假设第一列表用于记录可达组员的层2标识。表4为第一列表的一个示例。假设第三组员的层2标识为111101011001001，可见第三组员的层2标识在第一列表中的第一行。假设第一列表中的行从0开始排序时，第一行的序号为0。这样一来，终端的V2X层可以确定第三组员的编号为0。
表4
111101011001001
111101011001010
111101011001101
111101111001001
可以理解的是，上述第三组员的编号的确定方法可以应用于可达组员中的其他组员。
S305、终端的V2X层向终端的AS发送第三组员的编号。相应地，终端的AS接收终端的V2X层发送的第三组员的编号。
需要说明的是，本申请实施例不限制步骤S302-S303，和步骤S304-S305的执行顺序。也就是说，可以先执行步骤S302-S303，再执行步骤S304-S305；或者，先执行步骤S304-S305，再执行步骤S302-S303，或者，同时执行步骤S302-S303，和步骤S304-S305。
基于步骤S304-S305，终端的AS可以获知第三组员的编号，以便于保证在终端的AS接收到组播消息之后，终端的AS能够正确地反馈组播消息的ACK/NACK消息。其具体细节可以参考下文图12所示的实施例。
可选的，如图15所示，提供了另一种通信方法，该通信方法是在图9所示的通信方法的基础上实现的，具体地，在步骤S301之后，该通信方法还包括步骤S306-S307。
S306、终端的V2X层获取可达组员中除第三组员之外的其他所有组员的编号。
其中，其他所有组员中每一个组员的编号可以是该组员的层2标识、层1标识或者其他参数。
若其他所有组员的编号为其他参数，则终端的V2X层可以根据以下实现方式中的任意一种，确定其他所有组员的编号。
实现方式一、终端的V2X层根据可达组员的应用层标识的大小，确定其他所有组员的编号。
实现方式二、终端的V2X层根据可达组员的层2标识的大小，确定其他所有组员的编号。
实现方式三、终端的V2X层分配其他所有组员的编号。
实现方式四、终端的V2X层根据其他所有组员中每一个组员在第一表格所处的位置，确定其他所有组员中每一个组员的编号。
上述实现方式一至实现方式四的具体细节可以参考图9所示实施例中步骤S304中的描述，在此不再赘述。
S307、终端的V2X层向终端的AS发送可达组员中除第三组员之外其他所有组员的编号。
需要说明的是，本申请实施例不限制步骤S302-S303，和步骤S306-S307的执行顺序。也就是说，可以先执行步骤S302-S303，再执行步骤S306-S307；或者，先执行步骤S306-S307，再执行步骤S302-S303，或者，同时执行步骤S302-S303，和步骤S306-S307。
基于步骤S306-S307，终端的AS可以获取可达组员中除第三组员之外的其他所有组员的编号。
如图10所示，为本申请实施例提供的一种通信方法，该方法包括以下步骤：
S401、终端的应用层向终端的V2X层发送可达组员的应用层标识。相应地，终端的V2X层接收可达组员的应用层标识。
其中，步骤S401的具体描述可参考步骤S301，在此不再赘述。
S402、终端的V2X层根据可达组员的应用层标识，向终端的AS发送可达组员的层2标识。相应地，终端的AS接收可达组员的层2标识。
作为一种实现方式，终端的V2X层根据可达组员的应用层标识，生成/分配可达组员的层2标识；之后，终端的V2X层向终端的AS发送可达组员的层2标识。
其中，终端的V2X层生成/分配可达组员的层2标识的具体描述可参考图9所示实施例的步骤S301中的相关描述，在此不再赘述。
S403、终端的AS根据可达组员的层2标识，获得可达组员的个数。
其中，可达组员的个数等于可达组员的层2标识的个数。
基于步骤S401-S403，终端的AS层能够获知可达组员的个数，从而保证终端的AS能够在组播模式下执行HARQ机制。
可选的，如图10所示，该通信方法还包括步骤S404。
S404、终端的AS获得第三组员的编号。
其中，第三组员的编号可以是第三组员的层2标识、层1标识或者其他参数。
可选的，在第三组员为群组中可达组员中的一个的情况下，若第三组员的编号为其他参数，则终端的AS可以根据以下实现方式中的任意一种，确定第三组员的编号。
实现方式一、终端的AS根据可达组员的层2标识的大小，确定第三组员的编号。
实现方式二、终端的AS分配第三组员的编号。
上述实现方式一和实现方式二的细节可以参考图5所示实施例中步骤S201中的相关描述，在此不再赘述。
实现方式三、终端的AS根据第二列表中第三组员所处的位置，确定第三组员的编号。其中，第二列表用于记录可达组员的层2标识。
上述实现方式三的细节可以参考图9所示实施例中步骤S304中的相关描述，在此不再赘述。
可以理解的是，上述第三组员的编号的确定方法可以应用于可达组员中的其他组员。
需要说明的是，本申请实施例不限制步骤S403和步骤S404的执行顺序。也就是说，可以先执行步骤S403，再执行步骤S404；或者，先执行步骤S404，再执行步骤S403，或者，同时执行步骤S403，和S404。
基于步骤S404，终端的AS可以获知第三组员的编号，以便于保证在终端的AS接收到组播消息之后，终端的AS能够正确地反馈组播消息的ACK/NACK消息。其具体细节可以参考下文图12所示的实施例。
可选的，如图16所示，提供了另一种通信方法，该通信方法是在图10所示的通信方法的基础上实现的，具体地，在步骤S403之后，该通信方法还包括步骤S405。
S405、终端的AS获取可达组员中除第三组员之外的其他所有组员的编号。
其中，其他所有组员中每一个组员的编号可以是该组员的层2标识、层1标识或者其他参数。
若其他所有组员的编号为其他参数，则终端的V2X层可以根据以下实现方式中的任意一种，确定其他所有组员的编号。
实现方式一、终端的V2X层根据可达组员的层2标识的大小，确定其他所有组员的编号。
实现方式二、终端的V2X层分配其他所有组员的编号。
实现方式三、终端的V2X层根据其他所有组员中每一个组员在第一表格所处的位置，确定其他所有组员中每一个组员的编号。
上述实现方式一至实现方式三的具体细节可以参考图10所示的实施例中步骤S404的描述，在此不再赘述。
基于步骤S405，终端的AS可以获知可达组员中除第三组员之外的其他所有组员的编号。
如图11所示，为本申请实施例提供的一种通信方法，该方法包括以下步骤：
S501、终端的应用层获得可达组员的个数。
在本申请实施例中，终端对应群组中的第三组员。
可选的，终端的应用层执行步骤S501的触发条件包括但不限于：终端的V2X应用触发组播业务、群组的建立、群组的更新。
作为一种实现方式，终端的应用层获得可达组员的应用层标识；之后，终端的应用层根据可达组员的应用层标识，获得可达组员的个数。其中，可达组员的个数等于可达组员的应用层标识的个数。
可选的，终端的应用层获得群组中可达组员的应用层标识，包括：终端的应用层接收其他设备(例如应用服务器或者群组管理终端)发送的可达组员的应用层标识。
S502、终端的应用层向终端的V2X层发送可达组员的个数。相应地，终端的V2X层接收可达组员的个数。
S503、终端的V2X层向终端的AS发送可达组员的个数。相应地，终端的AS接收可达组员的个数。
基于上述步骤S501-S503，终端的AS获知可达组员的个数，以保证终端的AS能够在组播模式下正常执行HARQ机制。
可选的，如图11所示，该通信方法还包括步骤S504-S506。S504、终端的应用层 获得第三组员的编号。
其中，第三组员的编号可以是第三组员的层2标识、层1标识或者其他参数。
可选的，在第三组员为群组中可达组员中的一个的情况下，若第三组员的编号为其他参数，则终端的应用层可以根据以下实现方式中的任意一种，确定第三组员的编号。
实现方式一、终端的应用层根据可达组员的应用层标识的大小，确定第三组员的编号。
实现方式二、终端的应用层分配第三组员的编号。
上述实现方式一和实现方式二的细节可以参考图5所示实施例中步骤S201中的相关描述，在此不再赘述。
实现方式三、所述终端的应用层根据第三列表中第三组员所处的位置，确定第三组员的编号。其中，第三列表用于记录可达组员的应用层标识。
上述实现方式三的细节可以参考图9所示实施例中步骤S304中的相关描述，在此不再赘述。
实现方式四、终端的应用层接收来自于应用服务器或群组管理终端的第三组员的编号。
可以理解的是，上述第三组员的编号的确定方法可以应用于可达组员中的其他组员。
S505、终端的应用层向终端的V2X层发送第三组员的编号。相应地，终端的V2X层接收第三组员的编号。
S506、终端的V2X层向终端的AS发送第三组员的编号。相应地，终端的AS接收第三组员的编号。
需要说明的是，本申请实施例不限制步骤S501-S503，与步骤S504-S506的执行顺序。也就是说，可以先执行步骤S501-S503，再执行步骤S504-S506；或者，先执行步骤S504-S506，再执行步骤S501-S503，或者，同时执行步骤S501-S503，和S504-S506。
基于步骤S504-S506，终端的AS可以获知第三组员的编号，以便于保证在终端的AS接收到组播消息之后，终端的AS能够正确地反馈组播消息的ACK/NACK消息。其具体细节可以参考下文图12所示的实施例。
可选的，如图17所示，提供了另一种通信方法，该通信方法是在图10所示的通信方法的基础上实现的，具体地，该通信方法还包括步骤S507-S509。
S507、终端的应用层获取可达组员中除第三组员之外的其他所有组员的编号。
其中，其他所有组员中每一个组员的编号可以是该组员的层2标识、层1标识或者其他参数。
若其他所有组员的编号为其他参数，则终端的应用层可以根据以下实现方式中的任意一种，确定其他所有组员的编号。
实现方式一、终端的应用层根据可达组员的应用层标识的大小，确定其他所有可达组员的编号。
实现方式二、终端的应用层分配其他所有可达组员的编号。
实现方式三、终端的应用层根据其他所有组员中每一个组员在第三列表中所处的 位置，确定其他所有组员中每一个组员的编号。
实现方式四、终端的应用层接收来自应用服务器或者群组管理终端发送的其他所有组员的编号。
值得说明的是，上述实现方式一至实现方式四的具体细节可以参考图11所示实施例中步骤S504的描述，在此不再赘述。
S508、终端的应用层向终端的V2X层发送其他所有组员的编号。相应地，终端的V2X层接收终端的应用层发送的其他所有组员的编号。
S509、终端的V2X层向终端的AS发送其他所有组员的编号。相应地，终端的AS接收终端的V2X层发送的其他所有组员的编号。
需要说明的是，本申请实施例不限制步骤S501-S503，与步骤S507-S509的执行顺序。也就是说，可以先执行步骤S501-S503，再执行步骤S507-S509；或者，先执行步骤S507-S509，再执行步骤S501-S503，或者，同时执行步骤S501-S503，和S507-S509。
在图9、图10或者图11所示的实施例中，终端的应用层可以向终端的V2X层发送群组的应用层标识；之后，终端的V2X层根据群组的应用层标识，生成/分配群组的层2标识，并向终端的AS发送群组的层2标识。这样使得终端的AS获知群组的层2标识。从而，终端的AS所发送的组播消息可以包括群组的层2标识，以指示该组播消息对应的群组。
在图9、图10或者图11所示的实施例中，在第三组员不是群组中可达组员中的一个的情况下，终端的应用层还向终端的V2X层发送第三组的应用层标识；终端的V2X层根据第三组员的应用层标识，生成/分配第三组员的层2标识；之后，终端的V2X层向终端的AS发送第三组的层2标识。这样使得终端的AS获知第三组员的层2标识。从而，终端的AS在发送组播消息时，第三组员的层2标识可以作为组播消息中的源地址。
下面以图12所示的实施例，具体说明终端对应的组员的编号的功能。
如图12所示，为本申请实施例提供的一种通信方法，该方法包括以下步骤：
S601、组播接收端的AS接收组播发送端的AS发送的组播消息。
其中，组播消息可以包括群组的标识。
可以理解的是，组播接收端可以图4或图5所示实施例中的第一终端/第二终端，也可以是图9、图10或图11所示实施例中的终端。
组播接收端对应群组中的第四组员。可以理解的是，若组播接收端为图4或图5所示实施例中的第一终端，则第四组员即为第一组员。若组播接收端为图4或图5所示实施例中的第二终端，则第四组员即为第二组员。若组播接收端为图9、图10或图11所示实施例中的终端，则第四组员即为第三组员。
S602、组播接收端的AS根据第四组员的编号，确定反馈资源。
其中，反馈资源用于承载组播消息的ACK/NACK消息。反馈资源包括时域资源、频域资源、空域资源、和/或码域资源。
时域资源包括一个或多个时间单元，时间单元可以是子帧、时隙、正交频分复用(orthogonal frequency division multiplexing，OFDM)符号等。
频域资源包括一个或多个频域单元，频域单元可以是子载波、带宽。
空域资源包括波束、天线端口。
码域资源可以为在相同时域和频域上互不影响的符号序列。
在本申请实施例中，组员的编号与反馈资源之间存在对应关系。或者说，组员的编号用于确定该组员对应的反馈资源。
可选的，组员的编号与反馈资源之间存在对应关系，具体是指：组员的编号与反馈资源的索引/名称/标识/序号之间的对应关系。
示例性的，表5为组员的编号与反馈资源的索引之间对应关系的一个示例。结合表5进行举例说明，假设第四组员的编号为2，从而终端的AS在索引为2的反馈资源上发送ACK/NACK消息。
表5
可达组员的编号 反馈资源的索引
0 0
1 1
2 2
3 3
可以理解的是，组员的编号与反馈资源之间的对应关系可以是隐式存在的，例如编号0的组员对应第一个反馈资源，编号1的组员对应第二个反馈资源，以此类推，不再赘述。
或者，组员的编号与反馈资源之间的对应关系可以是显式存在的。可选的，在这种情况下，组播发送端可以以广播/组播的方式，向组播接收端发送组员的编号与反馈资源之间的对应关系。
S603、组播接收端的AS根据反馈资源，发送组播消息的ACK/NACK消息。
当组播接收端的AS接收到完整的组播消息时，组播接收端的AS根据反馈资源，发送组播消息的ACK消息，以使组播发送端的AS获知该组播接收端的AS已完整接收到组播消息。
当组播接收端的AS未接收到组播消息或者接收到不完整的组播消息时，组播接收端的AS根据反馈资源，发送组播消息的NACK消息，以触发组播发送端的AS重新发送组播消息。
基于图12所示的技术方案，一方面，组播接收端的AS根据组播接收对应的组员的编号，确定相应的反馈资源，从而保证了组播接收端的AS可以正常地向组播发送端反馈ACK/NACK消息。另一方面，组播发送端无需针对可达组员中的每一个组员逐一配置相应的反馈资源，从而有利于节省信令开销，也减少了组播流程的实现复杂度。
在图12所示的实施例中，组播发送端的AS存储着组员的编号与反馈资源之间的对应关系。因此，组播发送端的AS可以根据接收到的ACK/NACK消息所在的反馈资源的索引，确定反馈ACK/NACK消息的组员的编号。相应的，组播发送端的AS也可以根据未传输ACK/NACK消息的反馈资源的索引，确定未反馈ACK/NACK消息的组员的编号。
可选的，组播发送端的AS可以根据未反馈ACK/NACK消息的组员的编号，以单 播的方式向未反馈ACK/NACK消息的组员发送组播消息所携带的内容。
可以理解的是，上述组播发送端的AS或者组播接收端的AS可以获取组员的编号，可以参考图5、图9-图10、图14-图17所示的实施例。
一种可能的设计中，终端获取到的可达组员的编号可以是之前生成的编号，而不是在每次获取时重新生成的编号。例如，一个组人数为20的群组，生成了组员的编号为1,2,3,……,20。若终端发现了5个可达组员，这5个可达组员之前在群组中的编号分别为1,5,7,13,18。则终端可以确定这5个可达组员的编号为1,5,7,13,18，而不是重新为这5个可达组员重新分配编号1,2,3,4,5。
另一种可能的设计中，终端获取到的可达组员的编号可以是在每次获取时重新生成的编号。一个组人数为20的群组，生成了组员的编号为1,2,3,……,20。若终端发现了5个可达组员，这5个可达组员之前在群组中的编号分别为1,5,7,13,18。终端可以重新为这5个可达组员重新分配编号1,2,3,4,5。因此，终端可以确定这5个可达组员的编号为1,2,3,4,5。
上述两种设计可以适用于本文中的任一实施例。
上述主要从方法的角度对本申请实施例提供的方案进行了介绍。可以理解的是，终端为了实现上述功能，其包含了执行各个功能相应的硬件结构和/或软件模块。本领域技术人员应该很容易意识到，结合本文中所公开的实施例描述的各示例的算法步骤，本申请能够以硬件或硬件和计算机软件的结合形式来实现。某个功能究竟以硬件还是计算机软件驱动硬件的方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
本申请实施例可以根据上述方法示例对终端进行功能模块的划分，例如，可以对应每一个功能划分每一个功能模块，也可以将两个或两个以上的功能集成在一个处理模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。需要说明的是，本申请实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式。下面以采用对应每一个功能划分每一个功能模块为例进行说明：
图13为本申请实施例提供的一种通信装置的结构示意图。如图13所示，该通信装置包括：应用层模块1301、V2X模块1302、以及AS模块1303。其中，应用层模块1301可以用于支持通信装置执行图9中的步骤S301，图10中的步骤S401，图5中的步骤S501、S502、S504和S505，和/或用于支持本文描述的技术方案的其他过程。V2X层模块1302可以用于支持通信装置执行图4中的步骤S101-S109，图5中的步骤S201-S205，图9中的步骤S301-S305，图10中的步骤S401和S402，图11中的步骤S502、S503、S505和S506，和/或用于支持本文描述的技术方案的其他过程。AS模块1303可以用于支持通信装置执行图4中的步骤S106或者S109，图5中的步骤S202或者S204，图9中的步骤S303和S305，图10中的步骤S402-S404，图11中的步骤S503和S506，图12中的S601-S603，和/或用于支持本文描述的技术方案的其他过程。
本申请实施例还提供一种计算机可读存储介质，其上存储有指令，该指令被执行时执行上述方法实施例中的方法。
本申请实施例还提供一种包含指令的计算机程序产品，该指令被执行时执行上述方法实施例中的方法。
本申请实施例再提供一种芯片***，该芯片***包括处理器，用于实现本发明实施例的技术方法。在一种可能的设计中，该芯片***还包括存储器，用于保存本发明实施例通信设备必要的程序指令和/或数据。在一种可能的设计中，该芯片***还包括存储器，用于处理器调用存储器中存储的应用程序代码。该芯片***，可以由一个或多个芯片构成，也可以包含芯片和其他分立器件，本申请实施例对此不作具体限定。
本申请实施例还提供一种通信***，该通信***包括第一终端和第二终端。该第一终端用于执行图4或图5所示的通信方法。该第二终端用于执行图4或图5所示的通信方法。
结合本申请公开内容所描述的方法或者算法的步骤可以硬件的方式来实现，也可以是由处理器执行软件指令的方式来实现。软件指令可以由相应的软件模块组成，软件模块可以被存放于RAM、闪存、ROM、可擦除可编程只读存储器(erasable programmable ROM，EPROM)、电可擦可编程只读存储器(electrically EPROM，EEPROM)、寄存器、硬盘、移动硬盘、只读光盘(CD-ROM)或者本领域熟知的任何其它形式的存储介质中。一种示例性的存储介质耦合至处理器，从而使处理器能够从该存储介质读取信息，且可向该存储介质写入信息。当然，存储介质也可以是处理器的组成部分。处理器和存储介质可以位于ASIC中。另外，该ASIC可以位于核心网接口设备中。当然，处理器和存储介质也可以作为分立组件存在于核心网接口设备中。或者，存储器可以与处理器耦合，例如存储器可以是独立存在，通过总线与处理器相连接。存储器也可以和处理器集成在一起。存储器可以用于存储执行本申请实施例提供的技术方案的应用程序代码，并由处理器来控制执行。处理器用于执行存储器中存储的应用程序代码，从而实现本申请实施例提供的技术方案。
通过以上的实施方式的描述，所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，仅以上述各功能模块的划分进行举例说明，实际应用中，可以根据需要而将上述功能分配由不同的功能模块完成，即将装置的内部结构划分成不同的功能模块，以完成以上描述的全部或者部分功能。
在本申请所提供的几个实施例中，应该理解到，所揭露的装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述模块或单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个装置，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是一个物理单元或多个物理单元，即可以位于一个地方，或者也可以分布到多个不同地方。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成 的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个可读取存储介质中。基于这样的理解，本申请实施例的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该软件产品存储在一个存储介质中，包括若干指令用以使得一个设备(可以是单片机，芯片等)或处理器(processor)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、ROM、RAM、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何在本申请揭露的技术范围内的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (40)

  1. 一种通信方法，其特征在于，所述方法包括：
    第一终端的车联网V2X层发送第一消息，所述第一消息包括群组的标识，所述第一终端对应所述群组的第一组员；
    所述第一终端的V2X层接收所述第一消息的响应消息；
    所述第一终端的V2X层根据所述响应消息，确定所述群组中的可达组员的个数；
    所述第一终端的V2X层向所述第一终端的接入层AS发送所述可达组员的个数。
  2. 根据权利要求1所述的通信方法，其特征在于，所述方法还包括：
    所述第一终端的V2X层获得所述第一组员的编号，并向所述第一终端的AS发送所述第一组员的编号。
  3. 根据权利要求2所述的通信方法，其特征在于，所述第一组员是所述群组中的可达组员中的一个；所述第一终端的V2X层获得所述第一组员的编号，包括：
    所述第一终端的V2X层根据所述可达组员的应用层标识的大小，确定所述第一组员的编号；或者，
    所述第一终端的V2X层根据所述可达组员的层2标识的大小，确定所述第一组员的编号；或者，
    所述第一终端的V2X层分配所述第一组员的编号。
  4. 根据权利要求1至3任一项所述的通信方法，其特征在于，所述方法还包括：
    所述第一终端的V2X层获得所述可达组员中除所述第一组员之外其他所有组员的编号；
    所述第一终端的V2X层向所述第一终端的AS发送所述其他所有组员的编号。
  5. 根据权利要求4所述的通信方法，其特征在于，所述第一终端的V2X层获得所述其他所有组员的编号，包括：
    所述第一终端的V2X层根据所述可达组员的应用层标识的大小，确定所述其他所有组员的编号；或者，
    所述第一终端的V2X层根据所述其他所有组员的层2标识的大小，确定所述其他所有组员的编号；或者，
    所述第一终端的V2X层分配所述其他所有组员的编号；或者，
    所述第一终端的V2X层根据所述响应消息，确定其他所有组员的编号，其中，所述响应消息包括用于指示所述可达组员的编号的指示信息。
  6. 根据权利要求2或3所述的通信方法，其特征在于，所述方法包括：
    所述第一终端的AS接收组播消息；
    所述第一终端的AS根据所述第一组员的编号，确定反馈资源；
    所述第一终端的AS根据所述反馈资源，发送所述组播消息的应答ACK/否认应答NACK消息。
  7. 根据权利要求1至6任一项所述的通信方法，其特征在于，所述响应消息包括所述群组的标识以及所述群组中第二组员的标识，所述第二组员为所述群组中的可达组员中的一个。
  8. 根据权利要求7所述的通信方法，其特征在于，所述方法还包括：
    所述第一终端的V2X层向所述第二组员对应的第二终端发送第二消息，所述第二消息携带有所述可达组员的个数或所述可达组员的标识中的至少一种。
  9. 根据权利要求8所述的通信方法，其特征在于，所述第二消息包括以下任意一种：
    所述可达组员的编号；或者，
    所述第二组员的编号；或者，
    所述可达组员中除所述第一组员之外其他所有组员的编号。
  10. 一种通信方法，其特征在于，所述方法包括：
    第二终端的车联网V2X层接收来自第一终端的第一消息，所述第一消息包括群组的标识，所述第一终端对应所述群组中的第一组员，所述第二终端对应所述群组中的第二组员；
    所述第二终端的V2X层向所述第一终端发送所述第一消息的响应消息；
    所述第二终端的V2X层接收来自所述第一终端的第二消息；
    所述第二终端的V2X层根据所述第二消息，获得所述群组中的可达组员的个数；
    所述第二终端的V2X层向所述第二终端的接入层AS发送所述可达组员的个数。
  11. 根据权利要求10所述的通信方法，其特征在于，所述响应消息包括所述群组的标识以及所述第二组员的标识。
  12. 根据权利要求10或11所述的通信方法，其特征在于，所述第二消息携带有所述可达组员的个数或所述可达组员的标识中的至少一种。
  13. 根据权利要求10至12任一项所述的通信方法，其特征在于，所述第二消息包括以下任意一种：
    所述可达组员的编号；或者，
    所述第二组员的编号；或者，
    所述可达组员中除所述第一组员之外其他所有组员的编号。
  14. 根据权利要求13所述的通信方法，其特征在于，当所述第二消息包括所述第二组员的编号时，所述方法还包括：
    所述第二终端的V2X层根据所述第二消息，获得所述第二组员的编号；
    所述第二终端的V2X层向所述第二终端的AS发送所述第二组员的编号。
  15. 根据权利要求14所述的通信方法，其特征在于，所述方法还包括：
    所述第二终端的AS接收组播消息；
    所述第二终端的AS根据所述第二组员的编号，确定反馈资源；
    所述第二终端的AS根据所述反馈资源，发送所述组播消息的应答ACK/否认应答NACK消息。
  16. 一种通信方法，其特征在于，所述方法包括：
    终端的应用层向所述终端的车联网V2X层发送群组中的可达组员的应用层标识，所述终端对应所述群组中的第三组员；
    所述终端的V2X层根据所述可达组员的应用层标识，确定所述可达组员的个数；
    所述终端的V2X层向所述终端的接入层AS发送所述可达组员的个数。
  17. 根据权利要求16所述的通信方法，其特征在于，所述终端的V2X层根据所 述可达组员的应用层标识，确定所述可达组员的个数，包括：
    所述终端的V2X层根据所述可达组员的应用层标识，生成/分配所述可达组员的层2标识；
    所述终端的V2X层根据所述可达组员的层2标识，确定所述可达组员的个数。
  18. 根据权利要求16或17所述的通信方法，其特征在于，所述方法还包括：
    所述终端的V2X层获得所述第三组员的编号；
    所述终端的V2X层向所述终端的AS发送所述第三组员的编号。
  19. 根据权利要求18所述的通信方法，其特征在于，所述第三组员为所述群组中的可达组员中的一个；所述终端的V2X层获得所述第三组员的编号，包括：
    所述终端的V2X层根据所述可达组员的应用层标识的大小，确定所述第三组员的编号；或者，
    所述终端的V2X层根据所述可达组员的层2标识的大小，确定所述第三组员的编号；或者，
    所述终端的V2X层根据第一列表中所述第三组员所处的位置，确定所述第三组员的编号，所述第一列表用于记录所述可达组员的应用层标识或层2标识；或者，
    所述终端的V2X层分配所述第三组员的编号。
  20. 根据权利要求16至19任一项所述的通信方法，其特征在于，所述方法还包括：
    所述终端的V2X层获得所述可达组员中除所述第三组员之外其他所有组员的编号；
    所述终端的V2X层向所述终端的AS发送所述其他所有组员的编号。
  21. 根据权利要求20所述的通信方法，其特征在于，所述终端的V2X层获得所述其他所有组员的编号，包括：
    所述终端的V2X层根据所述可达组员的应用层标识的大小，确定所述其他所有组员的编号；或者，
    所述终端的V2X层根据所述其他所有组员的层2标识的大小，确定所述其他所有组员的编号；或者，
    所述终端的V2X层根据所述其他所有组员中每一个组员在第一列表中所处的位置，确定所述其他所有组员中每一个组员的编号，所述第一列表用于记录所述可达组员的应用层标识或层2标识；或者，
    所述终端的V2X层分配所述其他所有组员的编号。
  22. 根据权利要求18或19所述的通信方法，其特征在于，所述方法还包括：
    所述终端的AS接收组播消息；
    所述终端的AS根据所述第三组员的编号，确定反馈资源；
    所述终端的AS根据所述反馈资源，发送所述组播消息的应答ACK/否认应答NACK消息。
  23. 一种通信方法，其特征在于，所述方法包括：
    终端的应用层向所述终端的车联网V2X层发送群组中的可达组员的应用层标识，所述终端对应所述群组中的第三组员；
    所述终端的V2X层根据所述可达组员的应用层标识，向所述终端的接入层AS发送所述可达组员的层2标识；
    所述终端的AS根据所述可达组员的层2标识，确定所述可达组员的个数。
  24. 根据权利要求23所述的通信方法，其特征在于，所述方法还包括：
    所述终端的AS获得所述第三组员的编号。
  25. 根据权利要求24所述的通信方法，其特征在于，所述第三组员为所述群组中的可达组员中的一个；所述终端的AS获得所述第三组员的编号，包括：
    所述终端的AS根据所述可达组员的层2标识的大小，确定所述第三组员的编号；或者，
    所述终端的AS根据第二列表中所述第三组员所处的位置，确定所述第三组员的编号，所述第二列表用于记录所述可达组员的层2标识；或者，
    所述终端的AS分配所述第三组员的编号。
  26. 根据权利要求23所述的通信方法，其特征在于，所述方法还包括：
    所述终端的AS层获得所述可达组员中除所述第三组员之外其他所有组员的编号。
  27. 根据权利要求26所述的通信方法，其特征在于，所述终端的V2X层获得所述其他所有组员的编号，包括：
    所述终端的AS根据所述可达组员的层2标识的大小，确定所述其他所有组员的编号；或者，
    所述终端的AS根据所述其他所有组员中每一个组员在第二列表中所处的位置，确定所述其他所有组员中每一个组员的编号，所述第二列表用于记录所述可达组员的层2标识；或者，
    所述终端的AS分配所述其他所有组员的编号。
  28. 根据权利要求23或24所述的通信方法，其特征在于，所述方法还包括：
    所述终端的AS接收组播消息；
    所述终端的AS根据所述第三组员的编号，确定反馈资源；
    所述终端的AS根据所述反馈资源，发送所述组播消息的应答ACK/否认应答NACK消息。
  29. 一种通信方法，其特征在于，所述方法包括：
    终端的应用层获得群组中的可达组员的个数，所述终端对应所述群组中的第三组员；
    所述终端的应用层向所述终端的车联网V2X层发送所述可达组员的个数；
    所述终端的V2X层向所述终端的接入层AS发送所述可达组员的个数。
  30. 根据权利要求29所述的通信方法，其特征在于，所述终端的应用层获得群组中的可达组员的个数，包括：
    所述终端的应用层获取所述可达组员的应用层标识，并根据所述可达组员的应用层标识，确定所述可达组员的个数；或者，
    所述终端的应用层接收来自应用服务器或群组管理终端的所述可达组员的个数。
  31. 根据权利要求30所述的通信方法，其特征在于，所述终端的应用层获取所述可达组员的应用层标识，包括：
    所述终端的应用层接收来自应用服务器或群组管理终端的所述可达组员的应用层标识。
  32. 根据权利要求29至31任一项所述的通信方法，其特征在于，所述方法还包括：
    所述终端的应用层获得所述第三组员的编号；
    所述终端的应用层向所述终端的V2X层发送所述第三组员的编号；
    所述终端的V2X层向所述终端的AS发送所述第三组员的编号。
  33. 根据权利要求29所述的通信方法，其特征在于，所述第三组员为所述群组中的可达组员中的一个；所述终端的应用层获得所述第三组员的编号，包括：
    所述终端的应用层根据所述可达组员的应用层标识的大小，确定所述第三组员的编号；或者，
    所述终端的应用层根据第三列表中所述第三组员所处的位置，确定所述第三组员的编号，所述第三列表用于记录所述可达组员的应用层标识；或者，
    所述终端的应用层分配所述第三组员的编号；或者，
    所述终端的应用层接收来自应用服务器或群组管理终端的所述第三组员的编号。
  34. 根据权利要求29至33任一项所述的通信方法，其特征在于，所述方法还包括：
    所述终端的应用层获得所述可达组员中除所述第三组员之外其他所有组员的编号；
    所述终端的应用层向所述终端的V2X层发送所述其他所有组员的编号；
    所述终端的V2X层向所述终端的AS发送所述其他所有组员的编号。
  35. 根据权利要求34所述的通信方法，其特征在于，所述终端的V2X层获得所述其他所有组员的编号，包括：
    所述终端的应用层根据所述可达组员的应用层标识的大小，确定所述其他所有组员的编号；或者，
    所述终端的应用层根据所述其他所有组员中每一个组员在第三列表中所处的位置，确定所述其他所有组员中每一个组员的编号，所述第三列表用于记录所述可达组员的应用层标识；或者，
    所述终端的应用层分配所述其他所有组员的编号；或者，
    所述终端的应用层接收来自应用服务器或群组管理终端的所述其他所有组员的编号。
  36. 根据权利要求32或33所述的通信方法，其特征在于，所述方法还包括：
    所述终端的AS接收组播消息；
    所述终端的AS根据所述第三组员的编号，确定反馈资源；
    所述终端的AS根据所述反馈资源，发送所述组播消息的应答ACK/否认应答NACK消息。
  37. 一种通信装置，其特征在于，包括处理器和存储器，所述存储器和所述处理器耦合，所述处理器执行所述存储器中存储的指令时，实现权利要求1-36任一项所述的通信方法。
  38. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质包括计算 机指令，当所述计算机指令在计算机上运行时，使得所述计算机执行如权利要求1-36任一项所述的通信方法。
  39. 一种计算机程序产品，其特征在于，所述计算机程序产品包括指令，当所述计算机程序产品在计算机上运行时，使得所述计算机执行如权利要求1-36任一项所述的通信方法。
  40. 一种通信***，其特征在于，所述通信***包括第一终端和第二终端，所述第一终端用于执行权利要求1-9任一项所述的通信方法，所述第二终端用于执行权利要求10-15任一项所述的通信方法。
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