WO2020156020A1 - 一种通信方法及装置 - Google Patents

一种通信方法及装置 Download PDF

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Publication number
WO2020156020A1
WO2020156020A1 PCT/CN2020/070097 CN2020070097W WO2020156020A1 WO 2020156020 A1 WO2020156020 A1 WO 2020156020A1 CN 2020070097 W CN2020070097 W CN 2020070097W WO 2020156020 A1 WO2020156020 A1 WO 2020156020A1
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WIPO (PCT)
Prior art keywords
remote
information
relay
rrc
downlink
Prior art date
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PCT/CN2020/070097
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English (en)
French (fr)
Inventor
罗海燕
戴明增
Original Assignee
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 EP20747788.6A priority Critical patent/EP3911019B1/en
Publication of WO2020156020A1 publication Critical patent/WO2020156020A1/zh
Priority to US17/392,071 priority patent/US20210368417A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
    • H04W40/22—Communication route or path selection, e.g. power-based or shortest path routing using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H04W76/27—Transitions between radio resource control [RRC] states
    • 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
    • H04W76/19—Connection re-establishment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/04—Terminal devices adapted for relaying to or from another terminal or user
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices
    • H04W88/085—Access point devices with remote components

Definitions

  • This application relates to the field of communication technology, and in particular to a communication method and device.
  • the CU-DU architecture refers to the separation of the functions of the base station, and part of the functions of the base station are deployed in a centralized unit (CU), and another part of the functions are deployed in a distributed unit (DU).
  • One possible deployment method is to split the base station into CU and DU according to the protocol stack. For example, radio resource control (Radio Resource Control, RRC), service data adaptation protocol (Service Data Adaptation Protocol, SDAP), and packet data convergence protocol (Packet Data Convergence Protocol, PDCP) layers are deployed in the CU.
  • RRC Radio Resource Control
  • service data adaptation protocol Service Data Adaptation Protocol
  • SDAP Service Data Adaptation Protocol
  • Packet Data Convergence Protocol Packet Data Convergence Protocol
  • the remaining radio link control (RLC) layer, media access control (MAC) layer, and physical layer (physical, PHY) are deployed in the DU.
  • This application provides a communication method and device, which can implement a UE-to-Network relay communication process based on the CU-DU architecture.
  • this application provides a communication method, including: a CU generates a user context modification request message, the user context modification request message is used to request the DU to modify the context of the relay UE, and the user context modification request message carries the remote UE’s
  • the bearer identifier of the relay UE is the identifier of the bearer between the relay UE and the CU, and the logical channel is The logical channel between the remote UE and the relay UE; the CU sends a user context modification request message to the DU.
  • the CU determines the mapping relationship between the bearer identifier of the relay UE and the identifier of the logical channel between the relay UE and the remote UE, and sends a user context modification request message to the DU to request DU modification.
  • the relay UE can complete the forwarding of the RRC message or data packet for the remote UE according to the RRC reconfiguration message.
  • the user context modification request message also carries the bearer identifier of the remote UE that has a mapping relationship with the bearer identifier of the relay UE and the identifier of the logical channel.
  • the bearer identifier of the remote UE is the bearer identifier of the remote UE and the CU. logo.
  • the CU uses three of the bearer identifier of the relay UE, the bearer identifier of the remote UE, and the identifier of the logical channel between the relay UE and the remote UE.
  • the mapping relationship between the DU is convenient for the DU after receiving the user context modification request message, based on the remote UE’s bearer identity, and the logical channel identity between the remote UE and the relay UE and the remote UE’s bearer identity.
  • the mapping relationship generates RRC configuration information for the remote UE.
  • the method further includes: the CU sends a downlink RRC information transmission message to the DU.
  • the downlink RRC information transmission message includes the downlink RRC information of the remote UE, the identifier of the relay UE on the CU-DU interface, and the first indication.
  • the RRC information includes the downlink RRC message of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink RRC message.
  • the adaptation information is used to indicate that the downlink RRC message is a downlink RRC message of the remote UE, and the first indication is used to indicate the The downlink RRC message is externally encapsulated with adaptation information.
  • the transmission process of the downlink RRC message of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the CU receives an uplink RRC information transmission message sent by the DU, where the uplink RRC information transmission message includes the uplink RRC information of the remote UE, the identifier of the relay UE on the CU-DU interface, and the first indication.
  • the uplink RRC information includes the uplink RRC message of the remote UE and the PDCP layer and adaptation information encapsulated outside the uplink RRC message.
  • the adaptation information is used to indicate that the uplink RRC message is the uplink RRC message of the remote UE, and the first indication is used to indicate The uplink RRC message is externally encapsulated with adaptation information.
  • the adaptation layer when the adaptation layer is deployed in the protocol stack of the CU, the transmission process of the uplink RRC message of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the CU sends a downlink General Packet Radio Service Technology Tunneling Protocol GTP-U frame to the DU, where the downlink GTP-U frame includes the downlink data information of the remote UE, the first indication, and the GTP-U of the relay UE.
  • the downlink data information includes the downlink data packet of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink data packet.
  • the adaptation information is used to indicate that the downlink data packet is the downlink data of the remote UE Packet
  • the first indication is used to indicate that adaptation information is encapsulated outside the downlink data packet.
  • the adaptation layer when the adaptation layer is deployed in the protocol stack of the CU, the transmission process of the downlink data packet of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the CU receives an uplink GTP-U frame sent by the DU, where the uplink GTP-U frame includes uplink data information of the remote UE, a first indication, and a tunnel endpoint identifier of the GTP-U tunnel of the relay UE
  • the uplink data information includes the uplink data packet of the remote UE and the PDCP layer and adaptation information encapsulated outside the uplink data packet.
  • the adaptation information is used to indicate that the uplink data packet is the uplink data packet of the remote UE. It indicates that adaptation information is encapsulated outside the uplink data packet.
  • the adaptation layer when the adaptation layer is deployed in the protocol stack of the CU, the transmission process of the uplink data packet of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the CU sends a user context establishment request message to the DU, where the user context establishment request message includes the identity of the relay UE, the identity of the remote UE, and the mapping relationship between the bearer identity of the remote UE and the logical channel
  • the user context establishment request message is used to request the DU to establish the context of the remote UE.
  • the process of establishing the context of the remote UE in the UE-to-Network relay communication process can be realized.
  • the user context modification request message also carries a second indication, which is used to instruct the DU to add adaptation to the downlink data information or downlink RRC information when sending the downlink data information or downlink RRC information of the remote UE Information
  • adaptation information is used to indicate that the downlink data or downlink RRC information is downlink data information or downlink RRC information of the remote UE.
  • the method further includes: the CU receives from the DU the RRC connection establishment request message, the RRC reestablishment request message, or the RRC recovery request message of the remote UE forwarded by the relay UE.
  • the present application provides a communication method.
  • the method includes: a DU receives a user context modification request message sent by a CU, and the user context modification request message carries the identifier of the remote UE, the bearer identifier of the relay UE, and the relay
  • the bearer identifier of the UE is the identifier of the logical channel with the mapping relationship
  • the bearer identifier of the relay UE is the identifier of the bearer between the relay UE and the CU
  • the logical channel is the logical channel between the remote UE and the relay UE
  • DU Generate the RRC configuration information of the relay UE according to the identifier of the remote UE, the bearer identifier of the relay UE, and the identifier of the logical channel.
  • the RRC configuration information includes the identifier of the remote UE, the bearer identifier of the relay UE, and the identifier of the logical channel.
  • the mapping relationship includes the identifier of the remote UE
  • the DU can determine the mapping relationship between the bearer identifier of the relay UE and the identifier of the logical channel between the relay UE and the remote UE based on the user context modification request message sent by the CU, and regenerate the relay.
  • the RRC configuration information of the UE so that the subsequent CU can generate the RRC reconfiguration message of the relay UE according to the RRC configuration information of the relay UE, so that the relay UE can complete the RRC message or data packet for the remote UE according to the RRC reconfiguration message Forward.
  • the UE-to-Network relay communication process is realized under the CU-DU architecture.
  • the user context modification request message also carries the bearer identifier of the remote UE that has a mapping relationship with the bearer identifier of the relay UE and the identifier of the logical channel.
  • the bearer identifier of the remote UE is the bearer identifier of the remote UE and the CU.
  • Identifier; the mapping relationship between the bearer identifier of the relay UE and the identifier of the logical channel is specifically: the mapping relationship between the bearer identifier of the relay UE, the identifier of the logical channel, and the bearer identifier of the remote UE.
  • the DU can determine one of the bearer identifier of the relay UE, the bearer identifier of the remote UE, and the identifier of the logical channel between the relay UE and the remote UE based on the user context modification request message sent by the CU.
  • the mapping relationship between the remote UEs facilitates subsequent generation of RRC configuration information for the remote UE based on the bearer identifier of the remote UE and the mapping relationship between the identifier of the logical channel between the remote UE and the relay UE and the bearer identifier of the remote UE.
  • the method further includes: the DU receives a downlink RRC information transmission message sent by the CU, where the downlink RRC information transmission message includes the downlink RRC information of the remote UE, the identifier of the relay UE on the CU-DU interface, and the first indication.
  • the RRC information includes the downlink RRC message of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink RRC message.
  • the adaptation information is used to indicate that the downlink RRC message is a downlink RRC message of the remote UE, and the first indication is used to indicate the
  • the downlink RRC message is externally encapsulated with adaptation information; the DU sends the downlink RRC information encapsulating the RLC layer, MAC layer, and PHY layer to the relay UE.
  • the PHY layer, MAC layer, or RLC layer carries a third indication, and the third indication is used to Indicates that adaptation information is encapsulated outside the downlink RRC message.
  • the transmission process of the downlink RRC message of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the DU receives uplink RRC information of the remote UE sent by the relay UE, the uplink RRC information includes the uplink RRC message of the remote UE, and the PDCP layer and adaptation information encapsulated outside the uplink RRC message , RCL layer, MAC layer, and PHY layer.
  • the PHY layer, MAC layer or RLC layer carries a third indication.
  • the third indication is used to indicate that the uplink RRC message is encapsulated with adaptation information, and the adaptation information is used to indicate the uplink RRC.
  • the message is an uplink RRC message of the remote UE; the DU sends an uplink RRC information transmission message to the CU.
  • the uplink RRC information transmission message includes the identifier of the relay UE on the CU-DU interface, the first indication, the uplink RRC message, and the uplink RRC message encapsulated in the uplink.
  • PDCP layer and adaptation information outside the RRC message includes the identifier of the relay UE on the CU-DU interface, the first indication, the uplink RRC message, and the uplink RRC message encapsulated in the uplink.
  • the transmission process of the uplink RRC message of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the DU receives a downlink GTP-U frame sent by the CU, where the downlink GTP-U frame includes downlink data information of the remote UE, a first indication, and a tunnel endpoint identifier of the GTP-U tunnel of the relay UE
  • the downlink data information includes the downlink data packet of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink data packet.
  • the adaptation information is used to indicate that the downlink data packet is the downlink data packet of the remote UE.
  • the DU sends the downlink data information encapsulating the RLC layer, MAC layer, and PHY layer to the relay UE.
  • the PHY layer, MAC layer, or RLC layer carries a third indication, The three indications are used to indicate that adaptation information is encapsulated outside the downlink data packet.
  • the adaptation layer when the adaptation layer is deployed in the protocol stack of the CU, the transmission process of the downlink data packet of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the DU receives the uplink data information of the remote UE sent by the relay UE, the uplink data information includes the uplink data packet of the remote UE and the PDCP layer encapsulated outside the uplink data packet, adaptation information, RCL layer, MAC layer, and PHY layer.
  • the PHY layer, MAC layer or RLC layer carries a third indication.
  • the third indication is used to indicate that the uplink data packet is encapsulated with adaptation information, and the adaptation information is used to indicate the uplink data packet. Is an uplink data packet of a remote UE; the DU sends an uplink GTP-U frame to the CU.
  • the uplink GTP-U frame includes the first indication, the tunnel endpoint identifier of the GTP-U tunnel that relays the UE, the uplink data packet, and the The PDCP layer and adaptation information outside the uplink data packet, and the first indication is used to indicate that adaptation information is encapsulated outside the uplink data packet.
  • the adaptation layer when the adaptation layer is deployed in the protocol stack of the CU, the transmission process of the uplink data packet of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the DU receives a user context establishment request message sent by the CU, where the user context establishment request message includes the identity of the relay UE, the identity of the remote UE, and the mapping between the bearer identity of the remote UE and the logical channel
  • the user context establishment request message is used to request the DU to establish the context of the remote UE; the DU generates the RRC of the remote UE according to the mapping relationship between the identifier of the relay UE, the identifier of the remote UE, the bearer identifier of the remote UE and the logical channel Configuration information.
  • the process of establishing the context of the remote UE in the UE-to-Network relay communication process can be realized.
  • the user context establishment request message also carries a second indication, which is used to instruct the DU to send the downlink data information or downlink RRC information of the remote UE to the relay UE.
  • Adaptation information is added in the, and the adaptation information is used to indicate that the downlink data information or downlink RRC information is the downlink data information or downlink RRC information of the remote UE.
  • the method further includes: the DU receives a downlink RRC information transmission message sent by the CU, where the downlink RRC information transmission message includes the downlink RRC information of the remote UE and the identifier of the remote UE on the CU-DU interface, and the downlink RRC information includes the remote The UE's downlink RRC message and the PDCP layer encapsulated outside the downlink RRC message; the DU sends to the relay UE the downlink RRC information encapsulating adaptation information, RLC layer, MAC layer, and PHY layer, PHY layer, MAC layer or RLC layer
  • the third indication is used to indicate that the downlink RRC message is externally encapsulated with adaptation information, and the adaptation information is used to indicate that the downlink RRC message is a downlink RRC message of a remote UE.
  • the transmission process of the downlink RRC message of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the DU receives uplink RRC information sent by the relay UE, where the uplink RRC information includes the uplink RRC message of the remote UE and the PDCP layer, adaptation information, and RLC layer that are sequentially encapsulated outside the uplink RRC message , MAC layer and PHY layer, RLC layer, MAC layer or PHY layer carries a third indication, the third indication is used to indicate that the uplink RRC message is externally encapsulated with adaptation information, and the adaptation information is used to indicate that the uplink RRC message is remote.
  • the DU sends an uplink RRC information transmission message to the CU.
  • the uplink RRC information transmission message includes the bearer identifier for transmitting the uplink RRC information, the identifier of the remote UE on the CU-DU interface, the uplink RRC message, and the uplink RRC message encapsulated in the uplink RRC message External PDCP layer.
  • the transmission process of the uplink RRC message of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the DU receives a downlink GTP-U frame sent by the CU, where the downlink GTP-U frame includes the downlink data information of the remote UE and the tunnel endpoint identifier of the GTP-U tunnel of the remote UE, the downlink data information Including the downlink data packet of the remote UE and the PDCP layer encapsulated outside the downlink data packet; the DU sends the downlink data information encapsulating adaptation information, RLC layer, MAC layer and PHY layer to the relay UE, RLC layer, MAC layer or The PHY layer carries a third indication. The third indication is used to indicate that the downlink data packet is encapsulated with adaptation information, and the adaptation information is used to indicate that the downlink data packet is a downlink data packet of a remote UE.
  • the transmission process of the downlink data packet of the remote UE during the UE-to-Network relay communication process can be realized.
  • the method further includes: the DU receives uplink data information sent by the relay UE, the uplink data information includes the uplink data packet of the remote UE and the PDCP layer, adaptation information, and RLC layer sequentially encapsulated outside the uplink data packet , MAC layer and PHY layer, RLC layer, MAC layer or PHY layer carries a third indication, the third indication is used to indicate that the uplink data packet is externally encapsulated with adaptation information, and the adaptation information is used to indicate that the uplink data packet is remote UE's uplink data packet; the DU reads the adaptation information in the uplink data information according to the third instruction to determine the bearer identity used to transmit the uplink data information in the bearer identity of the remote UE, and is used to transmit the uplink data packet
  • the bearer identifier of the data information corresponds to the tunnel endpoint identifier of the GTP-U tunnel of the remote UE; the DU sends an uplink GTP-U frame to the CU.
  • the uplink GTP-U frame includes the bearer identifier used to transmit the uplink data information and the remote UE’s The tunnel endpoint identifier of the GTP-U tunnel, the uplink data packet, and the PDCP layer encapsulated outside the uplink data packet.
  • the transmission process of the uplink data packet of the remote UE during the UE-to-Network relay communication process can be realized.
  • an embodiment of the present application provides a communication device, which may be a CU or a chip in the CU.
  • the communication device has the function of implementing the method described in the first aspect. This function can be realized by hardware, or by hardware executing corresponding software.
  • the hardware or software includes one or more modules corresponding to the above-mentioned functions.
  • the device includes a processing unit and a communication unit.
  • the device may also include a storage unit.
  • the processing unit can complete the receiving or sending of information through the communication unit, and the processing unit can process the information so that the communication device implements the method described in the first aspect.
  • the processing unit is configured to generate a user context modification request message, the user context modification request message is used to request the DU to modify the context of the relay user equipment UE, and the user context modification request message carries the identifier of the remote UE and the relay
  • the bearer identifier of the UE and the identifier of the logical channel that has a mapping relationship with the bearer identifier of the relay UE.
  • the bearer identifier of the relay UE is the identifier of the bearer between the relay UE and the CU, and the logical channel is the remote UE and the middle Following the logical channel between the UEs; the processing unit is also used to send a user context modification request message to the DU through the communication unit.
  • the user context modification request message also carries the bearer identifier of the remote UE that has a mapping relationship with the bearer identifier of the relay UE and the identifier of the logical channel.
  • the bearer identifier of the remote UE is the bearer identifier of the remote UE and the CU. logo.
  • the processing unit is further configured to send a downlink RRC information transmission message to the DU through the communication unit.
  • the downlink RRC information transmission message includes the downlink RRC information of the remote UE, the identifier of the relay UE on the CU-DU interface, and the first indication
  • the downlink RRC information includes the downlink RRC message of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink RRC message.
  • the adaptation information is used to indicate that the downlink RRC message is the downlink RRC message of the remote UE. It indicates that adaptation information is encapsulated outside the downlink RRC message.
  • the processing unit is further configured to receive, through the communication unit, an uplink RRC information transmission message sent by the DU.
  • the uplink RRC information transmission message includes the uplink RRC information of the remote UE, the identifier of the relay UE on the CU-DU interface, and the first Indication, the uplink RRC information includes the uplink RRC message of the remote UE and the PDCP layer and adaptation information encapsulated outside the uplink RRC message.
  • the adaptation information is used to indicate that the uplink RRC message is the uplink RRC message of the remote UE.
  • the first indication Used to indicate that the uplink RRC message is externally encapsulated with adaptation information.
  • the processing unit is further configured to send a downlink GTP-U frame to the DU through the communication unit, where the downlink GTP-U frame includes downlink data information of the remote UE, a first indication, and a tunnel for the GTP-U tunnel of the relay UE Endpoint identifier, the downlink data information includes the downlink data packet of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink data packet.
  • the adaptation information is used to indicate that the downlink data packet is the downlink data packet of the remote UE.
  • the indication is used to indicate that adaptation information is encapsulated outside the downlink data packet.
  • the processing unit is further configured to receive the uplink GTP-U frame sent by the DU through the communication unit, where the uplink GTP-U frame includes the uplink data information of the remote UE, the first indication, and the GTP-U tunnel of the relay UE.
  • Tunnel endpoint identifier the uplink data information includes the uplink data packet of the remote UE and the PDCP layer and adaptation information encapsulated outside the uplink data packet.
  • the adaptation information is used to indicate that the uplink data packet is the uplink data packet of the remote UE.
  • An indication is used to indicate that adaptation information is encapsulated outside the uplink data packet.
  • the processing unit is further configured to send a user context establishment request message to the DU through the communication unit.
  • the user context establishment request message includes the identity of the relay UE, the identity of the remote UE, the bearer identity of the remote UE and the logical channel.
  • the user context establishment request message is used to request the DU to establish the context of the remote UE.
  • the user context modification request message also carries a second indication, which is used to instruct the DU to add adaptation to the downlink data information or downlink RRC information when sending the downlink data information or downlink RRC information of the remote UE Information
  • adaptation information is used to indicate that the downlink data or downlink RRC information is downlink data information or downlink RRC information of the remote UE.
  • the processing unit is further configured to receive the RRC connection establishment request message, the RRC re-establishment request message or the RRC recovery request message of the remote UE forwarded by the relay UE through the communication unit DU.
  • the processing unit may be a processor, for example, and the communication unit may include a network interface, for example.
  • the CU further includes a storage unit, and the storage unit may be a memory, for example.
  • the storage unit is used to store computer-executable instructions
  • the processing unit is connected to the storage unit, and the processing unit executes the computer-executable instructions stored in the storage unit, so that the CU executes the above-mentioned first aspect The method described.
  • the processing unit may be, for example, a processor, and the communication unit may be, for example, an input/output interface, a pin, or a circuit.
  • the processing unit can execute computer-executable instructions stored in the storage unit, so that the chip executes the communication method described in the first aspect or any one of the first aspects.
  • the storage unit is a storage unit in the chip, such as a register, a cache, etc., and the storage unit can also be a storage unit in the CU located outside the chip, such as a read-only memory (ROM). ) Or other types of static storage devices that can store static information and instructions, random access memory (RAM), etc.
  • an embodiment of the present application provides a communication device, which may be a DU or a chip in the DU.
  • the communication device has the function of implementing the method described in the first aspect. This function can be realized by hardware, or by hardware executing corresponding software.
  • the hardware or software includes one or more modules corresponding to the above-mentioned functions.
  • the device includes a processing unit and a communication unit.
  • the device may also include a storage unit.
  • the processing unit may complete the receiving or sending of information through the communication unit, and the processing unit may process the information so that the communication device implements the method described in the second aspect.
  • the processing unit is configured to receive, through the communication unit, a user context modification request message sent by the CU.
  • the user context modification request message carries the identifier of the remote UE, the bearer identifier of the relay UE, and the bearer identifier of the relay UE.
  • the identifier of the logical channel of the mapping relationship, the bearer identifier of the relay UE is the identifier of the bearer between the relay UE and the CU, and the logical channel is the logical channel between the remote UE and the relay UE;
  • the processing unit is also used for Generate the RRC configuration information of the relay UE according to the identifier of the remote UE, the bearer identifier of the relay UE, and the identifier of the logical channel.
  • the RRC configuration information includes the identifier of the remote UE, the bearer identifier of the relay UE, and the identifier of the logical channel.
  • the user context modification request message also carries the bearer identifier of the remote UE that has a mapping relationship with the bearer identifier of the relay UE and the identifier of the logical channel.
  • the bearer identifier of the remote UE is the bearer identifier of the remote UE and the CU.
  • Identifier; the mapping relationship between the bearer identifier of the relay UE and the identifier of the logical channel is specifically: the mapping relationship between the bearer identifier of the relay UE, the identifier of the logical channel, and the bearer identifier of the remote UE.
  • the processing unit is further configured to receive a downlink RRC information transmission message sent by the CU through the communication unit, where the downlink RRC information transmission message includes the downlink RRC information of the remote UE, the identifier of the relay UE on the CU-DU interface, and the first indication
  • the downlink RRC information includes the downlink RRC message of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink RRC message.
  • the adaptation information is used to indicate that the downlink RRC message is the downlink RRC message of the remote UE.
  • the processing unit is also used to send downlink RRC information encapsulating the RLC layer, MAC layer, and PHY layer to the relay UE through the communication unit, PHY layer, MAC layer or RLC layer It carries a third indication, and the third indication is used to indicate that adaptation information is encapsulated outside the downlink RRC message.
  • the processing unit is further configured to receive, through the communication unit, the uplink RRC information of the remote UE sent by the relay UE.
  • the uplink RRC information includes the uplink RRC message of the remote UE and the PDCP layer encapsulated outside the uplink RRC message.
  • the PHY layer, MAC layer or RLC layer carries a third indication.
  • the third indication is used to indicate that the uplink RRC message is encapsulated with adaptation information, and the adaptation information is used to indicate
  • the uplink RRC message is an uplink RRC message of the remote UE; the processing unit is also used to send an uplink RRC information transmission message to the CU through the communication unit.
  • the uplink RRC information transmission message includes the identifier of the relay UE on the CU-DU interface, the first Indication, the uplink RRC message, and the PDCP layer and adaptation information encapsulated outside the uplink RRC message.
  • the processing unit is further configured to receive, through the communication unit, a downlink GTP-U frame sent by the CU, where the downlink GTP-U frame includes downlink data information of the remote UE, a first indication, and the GTP-U tunnel of the relay UE.
  • Tunnel endpoint identifier the downlink data information includes the downlink data packet of the remote UE and the PDCP layer and adaptation information encapsulated outside the downlink data packet.
  • the adaptation information is used to indicate that the downlink data packet is a downlink data packet of the remote UE.
  • An indication is used to indicate that the downlink data packet is encapsulated with adaptation information; the processing unit is also used to send the downlink data information encapsulating the RLC layer, MAC layer, and PHY layer to the relay UE through the communication unit.
  • the layer or the RLC layer carries a third indication, and the third indication is used to indicate that the downlink data packet is externally encapsulated with adaptation information.
  • the processing unit is further configured to receive, through the communication unit, the uplink data information of the remote UE sent by the relay UE.
  • the uplink data information includes the uplink data packet of the remote UE and the PDCP layer encapsulated outside the uplink data packet, and Configuration information, RCL layer, MAC layer, and PHY layer.
  • the PHY layer, MAC layer or RLC layer carries a third indication. The third indication is used to indicate that the uplink data packet is encapsulated with adaptation information.
  • the adaptation information is used to indicate the The uplink data packet is the uplink data packet of the remote UE; the processing unit is also used to send the uplink GTP-U frame to the CU through the communication unit, and the uplink GTP-U frame includes the first indication and the tunnel that relays the UE’s GTP-U tunnel
  • the endpoint identifier, the uplink data packet, the PDCP layer and adaptation information encapsulated outside the uplink data packet, and the first indication is used to indicate that the uplink data packet is encapsulated with adaptation information.
  • the processing unit is further configured to receive, through the communication unit, a user context establishment request message sent by the CU.
  • the user context establishment request message includes the identity of the relay UE, the identity of the remote UE, the bearer identity of the remote UE, and the logical channel.
  • the user context establishment request message is used to request the DU to establish the context of the remote UE; the processing unit is also used to relay the UE’s identity, the remote UE’s identity, the remote UE’s bearer identity and the logical channel through the communication unit
  • the mapping relationship between the remote UEs generates RRC configuration information.
  • the user context establishment request message also carries a second indication, which is used to instruct the DU to send the downlink data information or downlink RRC information of the remote UE to the relay UE.
  • Adaptation information is added in the, and the adaptation information is used to indicate that the downlink data information or downlink RRC information is the downlink data information or downlink RRC information of the remote UE.
  • the processing unit is further configured to receive, through the communication unit, a downlink RRC information transmission message sent by the CU.
  • the downlink RRC information transmission message includes the downlink RRC information of the remote UE and the identifier of the remote UE on the CU-DU interface.
  • the information includes the downlink RRC message of the remote UE and the PDCP layer encapsulated outside the downlink RRC message; the processing unit is also used to send the downlink encapsulated adaptation information, RLC layer, MAC layer, and PHY layer to the relay UE through the communication unit RRC information, the PHY layer, MAC layer or RLC layer carries a third indication, the third indication is used to indicate that the downlink RRC message is externally encapsulated with adaptation information, and the adaptation information is used to indicate that the downlink RRC message is the downlink RRC of the remote UE news.
  • the processing unit is further configured to receive the uplink RRC information sent by the relay UE through the communication unit.
  • the uplink RRC information includes the uplink RRC message of the remote UE and the PDCP layer and adaptation information that are sequentially encapsulated outside the uplink RRC message , RLC layer, MAC layer, and PHY layer.
  • the RLC layer, MAC layer or PHY layer carries a third indication.
  • the third indication is used to indicate that the uplink RRC message is externally encapsulated with adaptation information, and the adaptation information is used to indicate the uplink RRC.
  • the message is an uplink RRC message of the remote UE; the processing unit is further configured to read the adaptation information in the uplink RRC information according to the third instruction to determine the bearer identity and the bearer identity used to transmit the uplink RRC information in the bearer identity of the remote UE.
  • the identifier of the remote UE on the CU-DU interface; the processing unit is also used to send an uplink RRC information transmission message to the CU through the communication unit.
  • the uplink RRC information transmission message includes a bearer identifier for transmitting uplink RRC information, and the remote UE is in the CU -The identifier of the DU interface, the uplink RRC message, and the PDCP layer encapsulated outside the uplink RRC message.
  • the processing unit is further configured to receive, through the communication unit, a downlink GTP-U frame sent by the CU, where the downlink GTP-U frame includes downlink data information of the remote UE and the tunnel endpoint identifier of the GTP-U tunnel of the remote UE.
  • the downlink data information includes the downlink data packet of the remote UE and the PDCP layer encapsulated outside the downlink data packet; the processing unit is also used to send the encapsulated adaptation information, RLC layer, MAC layer, and PHY layer to the relay UE through the communication unit
  • the third indication is carried in the RLC layer, MAC layer or PHY layer.
  • the third indication is used to indicate that the downlink data packet is encapsulated with adaptation information, and the adaptation information is used to indicate that the downlink data packet is for the remote UE.
  • Downlink data packet is carried in the RLC layer, MAC layer or PHY layer.
  • the processing unit is further configured to receive the uplink data information sent by the relay UE through the communication unit.
  • the uplink data information includes the uplink data packet of the remote UE and the PDCP layer and adaptation information sequentially encapsulated outside the uplink data packet , RLC layer, MAC layer, and PHY layer, the RLC layer, MAC layer or PHY layer carries a third indication, the third indication is used to indicate that the uplink data packet is encapsulated with adaptation information, and the adaptation information is used to indicate the uplink data
  • the packet is an uplink data packet of the remote UE; the processing unit is further configured to read the adaptation information in the uplink data information according to the third instruction to determine the bearer identity used to transmit the uplink data information in the bearer identity of the remote UE , And the tunnel endpoint identifier of the GTP-U tunnel of the remote UE corresponding to the bearer identifier used to transmit the uplink data information; the processing unit is further configured to send the uplink GTP-U frame to the CU through
  • the processing unit may be, for example, a processor, and the communication unit may include, for example, an antenna, a transceiver, and a network interface.
  • the communication device further includes a storage unit, and the storage unit may be a memory, for example.
  • the storage unit is used to store computer-executable instructions
  • the processing unit is connected to the storage unit, and the processing unit executes the computer-executable instructions stored in the storage unit, so that the DU executes the second aspect described above The method described.
  • the processing unit may be, for example, a processor, and the communication unit may be, for example, an input/output interface, a pin, or a circuit.
  • the processing unit can execute computer-executable instructions stored in the storage unit, so that the chip executes the communication method described in the second aspect or any one of the second aspects.
  • the storage unit is a storage unit in the chip, such as a register, a cache, etc.
  • the storage unit may also be a storage unit in the DU located outside the chip, such as a ROM or other storage units that can store static information and instructions Types of static storage devices, random access memory RAM, etc.
  • the processor mentioned in any one of the above can be a general-purpose central processing unit (Central Processing Unit, CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or A plurality of integrated circuits for controlling program execution of the method of the second aspect described above.
  • CPU Central Processing Unit
  • ASIC application-specific integrated circuit
  • an embodiment of the present application provides a computer storage medium that stores a program for implementing the method described in the first aspect.
  • the program runs in the device, the device is caused to execute the method of the first aspect described above.
  • an embodiment of the present application provides a computer storage medium that stores a program for implementing the method described in the second aspect.
  • the program runs in the device, the device is caused to execute the method of the second aspect described above.
  • the embodiments of the present application provide a computer program product, the program product includes a program, and when the program is executed, the method described in the first aspect is executed.
  • the embodiments of the present application provide a computer program product, the program product includes a program, and when the program is executed, the method described in the second aspect is executed.
  • the present application provides a communication system including the communication device described in the third aspect and the communication device described in the fourth aspect.
  • Figure 1 is a schematic diagram of a UE-to-Network relay communication system provided by this application;
  • Figure 2 is a schematic structural diagram of a base station deployed based on the CU-DU architecture provided by this application;
  • Figure 3 is a schematic diagram of a possible user plane protocol stack provided by this application.
  • Figure 4 is a schematic diagram of a possible control plane protocol stack provided by this application.
  • Figure 5 is a schematic diagram of the communication principle of a UE-to-Network relay provided by this application;
  • FIG. 6 is a flowchart of an embodiment of a communication method provided by this application.
  • FIG. 7 is a schematic diagram of another possible user plane protocol stack provided by this application.
  • FIG. 8 is a schematic diagram of another possible control plane protocol stack provided by this application.
  • Figure 9 is a schematic diagram of another UE-to-Network relay communication principle provided by this application.
  • FIG. 10 is a flowchart of an embodiment of another communication method provided by this application.
  • FIG. 11 is a schematic structural diagram of a communication device provided by this application.
  • FIG. 12 is a schematic structural diagram of a CU provided by this application.
  • FIG. 13 is a schematic structural diagram of a DU provided by this application.
  • association relationship means that there can be three kinds of relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B alone exists.
  • a and/or B can mean: A alone exists, A and B exist at the same time, and B alone exists.
  • a plurality of means two or more.
  • the communication method provided in this application is used to implement UE-to-Network relay communication under the CU-DU architecture.
  • the UE-to-Network relay communication system based on L2 relay and the base station adopting the CU-DU architecture will be exemplarily introduced below in conjunction with the accompanying drawings.
  • a UE-to-Network relay communication system includes a base station and multiple user equipment (UEser equipment, UE).
  • UE user equipment
  • some UEs may serve as relays and provide relay services for another portion of UEs.
  • a UE that can provide a relay service is referred to as a relay UE in the following, and a UE that exchanges information with a base station through the relay UE is referred to as a remote (remote) UE.
  • the remote UE sends its own data and RRC messages to the relay UE, and the relay UE forwards the data and RRC messages of the remote UE through the bearer between the relay UE and the base station To the base station.
  • the bearer may be a data radio bearer (DRB) and a signaling radio bearer (DRB) between the relay UE and the base station.
  • DRB data radio bearer
  • DRB signaling radio bearer
  • the relay UE forwards the data of the remote UE to the base station through its own DRB, and forwards the RRC message of the remote UE to the base station through its own SRB. It is not ruled out that the relay UE forwards the RRC message of the remote UE to the base station through its own DRB, and forwards the data of the remote UE to the base station through its own SRB.
  • the base station in FIG. 1 may be a base station deployed based on the CU-DU architecture, that is, the functions of the traditional base station in the LTE system are respectively deployed in the two units of the CU and DU.
  • the RLC layer, MAC layer, and PHY layer functions of the traditional base station in the LTE system are deployed in the DU, and the remaining functions (for example, the RRC layer and the PDCP layer functions) are deployed in the CU.
  • the non-access stratum (NAS) function of the core network in the LTE system is also deployed in the CU.
  • the function of the SDAP layer may also be deployed on the PDCP layer in the CU.
  • a base station deployed based on the CU-DU architecture can consist of one CU and multiple DUs, and multiple DUs can share one CU, thereby reducing costs and expanding the edge network.
  • the CU and DU are connected through the F1 interface, and in the LTE system, the CU and DU are connected through the V1/W1 interface.
  • the CU and the CU are connected through the Xn interface to realize the information exchange between the base stations through the Xn interface on behalf of the base station.
  • the CU is connected to the 5G core network (5GC) through the NG interface to exchange information with the core network equipment through the NG interface on behalf of the base station.
  • 5GC may include access and mobility management functions (AMF) and/or user plane functions (UPF) in the 5G system.
  • AMF access and mobility management functions
  • UPF user plane functions
  • the UE involved in this application may be a handheld device with wireless communication function, a vehicle-mounted device, a wearable device, a computing device or other connected to a wireless modem Processing equipment, as well as various forms of UE, mobile station (mobile station, MS), terminal (terminal), terminal equipment (terminal equipment), etc.
  • mobile station mobile station, MS
  • terminal terminal equipment
  • terminal equipment terminal equipment
  • an adaptation layer is generally set in the protocol stack between the relay UE and the base station for the relay UE or the base station to learn about the remote UE, the bearer of the remote UE, and/or the logic between the remote UE and the relay UE.
  • Channel adaptation information is generally set in the protocol stack between the relay UE and the base station for the relay UE or the base station to learn about the remote UE, the bearer of the remote UE, and/or the logic between the remote UE and the relay UE.
  • the relay UE can learn the received data packet/RRC message of the remote UE through which DRB/SRB of the relay UE to be transmitted to the base station according to the RRC configuration information of the base station, and then the data packet of the remote UE
  • the adaptation information of the adaptation layer is encapsulated outside the /RRC message, so that the base station can learn which remote UE the data packet/RRC message is, which bearer, or which UE it is, and which remote UE passes through the logical channel between the relay UE Transmission.
  • the adaptation information encapsulated by the base station outside the data packet/RRC message after the relay UE receives the data packet/RRC message from the base station through DRB/SRB, it is encapsulated outside the data packet/RRC message through the base station
  • the adaptation information knows which remote UE needs to be forwarded and which bearer is sent to the remote UE, or which logical channel between the relay UE and the remote UE is sent to the remote UE.
  • the adaptation layer can be deployed in the CU protocol stack or in the DU protocol stack.
  • the communication method provided in the present application will be exemplarily described in two deployment modes: deploying the adaptation layer in the protocol stack of the CU and deploying the adaptation layer in the protocol stack of the DU.
  • a possible user plane protocol stack between the remote UE, relay UE, CU and DU in the UE-to-Network relay communication system can be as shown in Figure 3. Show.
  • the remote UE and the relay UE exchange information through the PC5 interface, and establish an end-to-end PDCP layer to interact with the CU.
  • the relay UE and DU exchange information through the Uu interface.
  • the PDCP packet of the remote UE is transparently transmitted to the CU through the relay UE and DU, and the RLC packet, MAC packet, and PHY packet need to be processed by the relay UE and DU.
  • the user plane protocol stack of the remote UE includes the PDCP layer, the RLC layer, the MAC layer, and the PHY layer on the PC5 interface; the relay UE includes the RLC layer and the MAC layer in the user plane protocol stack of the PC5 interface.
  • PHY layer the user plane protocol stack of the Uu interface with the DU includes the RLC layer, the MAC layer, and the PHY layer.
  • the user plane protocol stack of the relay UE also includes an adaptation layer, and the adaptation information of the adaptation layer is transparently transmitted to the CU through the DU.
  • the user plane protocol stack of the Uu interface between the DU and the relay UE includes the RLC layer, the MAC layer, and the PHY layer.
  • the user plane protocol stack between DU and CU includes layer 1/layer 2 (layer 1/layer 1, L1/L2) layer, user datagram protocol/Internet protocol (User Datagram Protocol/Internet Protocol, UDP/IP) layer, General Packet Radio Service Technology Tunneling Protocol (General Packet Radio Service Tunneling Protocol User Plane, GTP-U) layer.
  • the user plane protocol stack in the CU includes the L1/L2 layer, UDP/IP layer, GTP-U layer with the DU, the adaptation layer with the relay UE, and the PDCP layer with the remote UE on the Uu interface .
  • a possible control plane protocol stack between the remote UE, the relay UE, the CU, and the DU in the UE-to-Network relay communication system may be as shown in FIG. 4.
  • the control plane protocol stack of the remote UE includes the RRC layer and the PDCP layer with the CU, and the RLC layer, the MAC layer, and the PHY layer with the relay UE at the PC5 interface.
  • the control plane protocol stack of the relay UE includes the RLC layer, MAC layer, and PHY layer on the PC5 interface with the remote UE, the RLC layer, MAC layer, and PHY layer on the Uu interface with the DU, and the compatibility with the CU. Distribution layer.
  • the control plane protocol stack of the DU includes the RLC layer, MAC layer and PHY layer on the Uu interface with the relay UE, the L1/L2 layer with the CU, and the stream control transmission protocol/Internet protocol (Stream Control Transmission Protocol/Internet). Protocol, SCTP/IP) layer, F1 Application Protocol (F1AP) layer.
  • the control plane protocol stack of the CU includes the L1/L2 layer, SCTP/IP layer and F1AP layer with the DU, the adaptation layer with the relay UE, and the PDCP layer and the RRC layer with the remote UE on the Uu interface. .
  • this application provides two schemes, including scheme 1 and scheme 2 as described below.
  • the first solution is that when transmitting the data packet/RRC message of the relay UE, the protocol stack of the CU and the relay UE does not include the adaptation layer, and when transmitting the data packet/RRC message of the remote UE, the CU and the relay UE
  • the adaptation layer will be included in the protocol stack. That is, for the uplink, when the relay UE sends an uplink data packet/uplink RRC message, if the relay UE sends its own uplink data packet/uplink RRC message, the relay UE does not need to send the uplink data packet/uplink RRC message.
  • RRC message encapsulates adaptation information.
  • the relay UE needs to encapsulate adaptation information for the uplink data packet/uplink RRC message to indicate to the CU that the uplink data packet/uplink RRC message is from the remote UE .
  • the CU sends a downlink data packet/downlink RRC message, if it is sending a relay UE downlink data packet/downlink RRC message, the CU does not need to be the downlink data packet/downlink RRC message Package adaptation information.
  • the CU needs to encapsulate adaptation information for the downlink data packet/downlink RRC message to indicate to the relay UE that the downlink data packet/downlink RRC message is from the remote UE . Since the adaptation layer may or may not exist, it is necessary for the relay or base station to indicate whether the counterparty adaptation layer exists when sending each data packet/RRC message.
  • the second solution is that the protocol stack of the CU and the relay UE always includes an adaptation layer. For uplink, whether the relay UE sends its own data packet/RRC message or forwards the data packet/RRC message of the remote UE, the relay UE will encapsulate the adaptation information for the sent data packet/RRC message for the CU to learn Whether the data packet/RRC message sent by the relay UE belongs to the remote UE or the relay UE itself.
  • the CU For the downlink, whether the CU sends data packets/RRC messages to remote UEs through the relay UE, or directly sends data packets/RRC messages to the relay UE, the CU will encapsulate the configuration information for the sent data packets/RRC messages for use Then the UE knows whether the data packet/RRC message sent by the CU is sent to the relay UE or to the remote UE. For the second solution, since the adaptation layer always exists, the relay or base station does not need to indicate whether the counterparty adaptation layer exists when sending each data packet/RRC message.
  • the DU since the adaptation layer is deployed in the CU protocol stack, the DU does not need to determine whether to receive the data packet/RRC message sent by the relay UE Is it the relay UE or which remote UE.
  • the DU can be directly sent by the relay UE to the GTP-U tunnel corresponding to the DRB of the data packet, and the data packet is transmitted to the CU.
  • the DU For the RRC message of the control plane, the DU directly sends the RRC message to the CU through the control plane message of the interface between the CU-DU related to the relay UE (for example, the F1 interface in the 5G system).
  • the CU sends the data packet/RRC message to the PDCP entity corresponding to the relay UE (for the communication route, see the thick solid line shown in Figure 5, PDCP1 Is the PDCP entity corresponding to the relay UE). If the data packet/RRC message is from a remote UE, the CU will determine the data packet based on the indication of the adaptation information of the adaptation layer after receiving the data packet/RRC message from the GTP-U tunnel or F1 interface of the relay UE The /RRC message is which bearer of which remote UE.
  • the CU determines that the data packet/RRC message belongs to the remote UE1 based on the adaptation information, the CU sends the data packet/RRC message to the corresponding PDCP entity (refer to the dotted line shown in Figure 5 for the communication route, and PDCP2 is the one corresponding to the relay UE. PDCP entity).
  • the adaptation layer when a remote UE requests the base station of the CU-DU architecture to establish an RRC connection through the relay UE, or request the restoration of the RRC connection, or request reconfiguration.
  • the CU and DU may not need to establish a context for the remote UE, but the context of the relay UE needs to be modified so that the relay UE can provide relay services for the remote UE.
  • a flowchart of an embodiment of a communication method provided by this application mainly describes that when the adaptation layer is deployed on the CU side, the remote UE requests the base station to establish an RRC connection and restore through the relay UE. RRC connection, or the process of requesting to re-establish an RRC connection.
  • the method includes:
  • Step 601 The CU generates a user context modification request (UE context modification request) message.
  • the user context modification request message is used to request the DU to modify the context of the relay UE.
  • the user context modification request message carries the identifier of the remote UE and the relay.
  • the bearer identifier of the UE and the identifier of the logical channel that has a mapping relationship with the bearer identifier of the relay UE, the bearer identifier of the relay UE is the identifier of the bearer between the relay UE and the CU, and the logical channel is the remote UE Logical channel with the relay UE.
  • the logical channel between the remote UE and the relay UE is the logical channel of the side link between the remote UE and the relay UE, or the PC5 interface between the remote UE and the relay UE (It can also be called a sidelink interface) logical channel.
  • the remote UE and the relay UE exchange information through the logical channel by means of direct transmission.
  • the CU after the CU receives a request message from the remote UE (for example, an RRC connection request message, an RRC re-establishment request message, or an RRC recovery request message), it can generate a user context modification request message to request the DU to be modified to The remote UE provides the context of the relay UE for the relay service.
  • a request message from the remote UE for example, an RRC connection request message, an RRC re-establishment request message, or an RRC recovery request message
  • the identifier of the remote UE may be the identifier of the remote UE carried in the request message of the remote UE received by the CU.
  • the identifier of the remote UE may be the layer 2 identification (L2ID) of the remote UE, or the identifier of the PC5 interface of the remote UE between the remote UE and the relay UE, or the L2ID of the remote UE The combination of the logo with the PC5 interface.
  • the identifier of the remote UE may be carried in the request message by the remote UE itself, or may be carried in the adaptation information when the relay UE forwards the request message.
  • the CU determines that it is the request of the remote UE through the received identifier of the remote UE, and the relay UE that forwards the request message serves as a relay to provide a relay service for the remote UE. Therefore, the CU needs to allocate the bearer of the relay UE to the remote UE, and determine which bearer of the relay UE forwards the data packet/RRC message of the remote UE. That is, the CU needs to determine the bearer identifier and the logical channel of the relay UE.
  • the mapping relationship between the identities Exemplarily, the CU may request to add DRB and SRB for the relay UE. Then determine the mapping relationship between the newly added DRB identifier and the SRB identifier and the logical channel identifier pair between the relay UE and the remote UE.
  • the CU may also modify the identifier set of the logical channel corresponding to the identifiers of the DRB and SRB allocated for the relay UE, that is, add the identifier of the remote UE and the identifier of the logical channel between the relay UE and the remote UE To the logical channel identifier set corresponding to the DRB and SRB identifiers allocated to the relay UE.
  • the CU may allocate a different SRB or DRB of the relay UE to each logical channel. It is also possible to allocate the same SRB or DRB of the relay UE to the multiple logical channels. That is, one bearer of the relay UE may correspond to one or more logical channels with different remote UEs.
  • the remote UE2 requests an RRC connection from the CU and DU through the relay UE, and the remote UE1 has completed the RRC connection through the relay UE.
  • the current bearer usage of the relay UE is: the SRB1 and DRB1 of the relay UE are used to transmit the RRC messages and data packets of the relay UE, and the logical channel LCID1 between the SRB2 of the relay UE and the remote UE1 and the relay UE has Mapping relationship (that is, the SRB2 of the relay UE transmits the uplink and downlink RRC messages of the remote UE1), the DRB2 of the relay UE and the logical channel LCID2 between the remote UE1 and the relay UE have a mapping relationship (that is, the DRB2 of the relay UE transmits Uplink and downlink data packets of remote UE1).
  • the CU When the CU receives the RRC connection request message of the remote UE2 forwarded by the relay UE, the CU can determine that the logical channels LCID3 and LCID4 of the PC5 interface between the remote UE and the relay UE are the RRC messages used to transmit SRB1 and SRB2 The logical channels LCID5 and LCID6 are logical channels used to transmit data packets of DRB1 and DRB2 of the remote UE. Then the CU allocates the SRB of the relay UE to LCID3 and LCID4, and allocates the DRB of the relay UE to LCID5 and LCID6.
  • the CU establishes the mapping relationship between the SRB2 identity of the relay UE and LCID3 and LCID4 to determine the uplink and downlink RRC messages corresponding to the SRB1 and SRB2 of the remote UE2 transmitted on the logical channels LCID3 and LCID4 transmitted by the SRB2 of the relay UE. . Then, the CU can add LCID3 and LCID4 to the set of identities of the logical channels corresponding to the identity of the SRB2 of the relay UE. After modification, the identity of the SRB2 of the relay UE corresponds to the identity of the remote UE1 and LCID1, and the identity of the remote UE2 And LCID3, LCID4.
  • the CU requests to increase the relayed DRB, and establishes the mapping relationship between the added DRB and LCID5 and LCID6. For example, request to add DRB3, and establish the mapping relationship between the ID of the relay UE's DRB3 and LCID5, LCID6 to determine the uplink and downlink of the DRB1 and DRB2 of the remote UE2 transmitted by the DRB3 of the relay UE. data pack.
  • the remote UE’s identifier, the modified or added relay UE’s bearer identifier, and the modified or added relay UE’s The identifier of the logical channel whose bearer identifier has a mapping relationship is carried in the user context modification request message and sent to the DU. To request the DU to modify the RRC configuration and context of the relay UE.
  • the user context modification request message carries the identity of the remote UE2, the identity of the SRB2 of the relay UE, the LCID3 and LCID4 corresponding to the identity of the SRB2 of the relay UE, the identity of the DRB3 of the relay UE, and the identity of the relay UE.
  • the ID of DRB3 corresponds to LCID5 and LCID6.
  • the CU requests the DU to modify the context of the relay UE through the user context modification request message, and generates RRC configuration information for the relay UE, so that the RRC configuration information of the relay UE has the identifier of the remote UE2 and the SRB2 of the relay UE.
  • the mapping relationship between the identifier of the, and the LCID3 and LCID4 the mapping relationship between the identifier of the DRB3 of the relay UE and the LCID5 and LCID6.
  • the CU may carry the GTP-U tunnel of the DRB3 of the relay UE in the user context modification request message on the CU side Tunnel endpoint identity (TEID) to request the DU to feed back the TEID of the DRB3 GTP-U tunnel on the DU side of the relay UE.
  • TEID Tunnel endpoint identity
  • the RRC configuration information of the remote UE needs to include the bearer identifier of the remote UE and the logical channel between the remote UE and the relay UE.
  • the bearer identifier of the remote UE is the identifier of the bearer between the remote UE and the CU. That is to say, in the process of generating the user context modification request message by the CU, the CU can establish the bearer identity of the relay UE, the bearer identity of the remote UE, and the identity of the logical channel between the relay UE and the remote UE.
  • the mapping relationship between There is a one-to-one correspondence between the bearer of the remote UE and the logical channel between the relay UE and the remote UE.
  • DRB1 of remote UE2 corresponds to LCID5
  • DRB2 of remote UE2 corresponds to LCID6
  • SRB1 of remote UE2 corresponds to LCID3
  • SRB2 of remote UE2 corresponds to LCID4.
  • the DRB3 of the relay UE provides forwarding services for the data packets transmitted on the DRB1 and DRB2 of the remote UE2
  • the SRB2 of the relay UE2 is the RRC message transmitted on the SRB1 and SRB2 of the remote UE2.
  • the user context modification request message may be encapsulated in a CU-DU interface message and sent to the DU.
  • the user context modification request message may be encapsulated in an F1 message, and the CU sends it to the DU through the F1 interface with the DU.
  • the F1 message encapsulating the user context modification request message may carry the identifier of the relay UE on the CU-DU interface, including the CU side identifier of the F1 interface assigned by the CU to the relay UE and the DU assigned to the relay UE. DU side identification of the F1 interface.
  • the DU and CU can identify the user context modification request message by relaying the UE's identity on the F1 interface.
  • the user context modification request message also carries the quality of service (QoS) information of the modified or added DRB, and the QoS information of the logical channel corresponding to the modified or added DRB, so that the DU is a remote UE Configure the resource pool for the PC5 interface.
  • QoS quality of service
  • Step 602 The CU sends a user context modification request message to the DU.
  • Step 603 The DU generates RRC configuration information of the relay UE according to the identifier of the remote UE, the bearer identifier of the relay UE, and the identifier of the logical channel.
  • the RRC configuration information includes the identifier of the remote UE, the bearer identifier of the relay UE, and the logical channel. The mapping relationship between the identities of the channels.
  • the DU After receiving the user context modification request message, the DU confirms that the context of the relay UE needs to be modified, and generates the RRC configuration information of the relay UE according to the information carried in the user context modification request message.
  • the RRC configuration information of the relay UE includes the identifier of the remote UE and the mapping relationship between the bearer identifier of the relay UE and the identifier of the logical channel between the relay UE and the remote UE.
  • the CU also carries the bearer identifier of the remote UE in the user context modification request message
  • the RRC configuration information generated by the DU for the relay UE may include the identifier of the remote UE and the identifier of the relay UE.
  • the RRC configuration information may specifically be cell group configuration (Cell Group Config) information.
  • the remote UE2 in the RRC configuration information of the relay UE generated by the DU, the bearer identifier of the relay UE, the bearer identifier of the remote UE2, and the identifier of the logical channel between the relay UE and the remote UE2
  • Table 1 The mapping relationship between the three can be shown in Table 1 below:
  • the DRB3 of the relay UE requests the added DRB for the CU, so when the DU generates the configuration information of the relay UE, it also needs to allocate the DRB3 of the added relay UE to the DU side of the corresponding GTP-U tunnel.
  • TEID The TEID on the DU side is carried in a user context modification response (UE context modification response) message and fed back to the CU to complete the establishment of the GTP-U tunnel corresponding to the DRB3 of the relay UE.
  • the RRC configuration information of the relay UE may also include resource pool information of the PC5 interface between the remote UE configured by the DU and the relay UE.
  • the configuration of the resource pool may include side link discontinuous transmission configuration (sl-DiscConfig), side link common configuration (sl-CommonConfig), side link car networking dedicated configuration (sl-V2X-ConfigDedicated), car networking Mobile control information (mobilityControlInfoV2X), etc.
  • the DU can also modify the context of the relay UE.
  • the RRC configuration information for the remote UE is generated, that is, the cell group configuration information is generated for the remote UE.
  • the DU generates the RRC configuration information of the remote UE according to the identifier of the remote UE, the bearer identifier of the remote UE, and the identifier of the logical channel.
  • the RRC configuration information of the remote UE includes the mapping relationship between the bearer identifier of the remote UE and the identifier of the logical channel, the underlying information configured by the DU for the remote UE, and may also include the identifier of the relay UE.
  • the DU and CU do not need to establish a context for the remote UE on the CU-DU interface, the DU needs to provide an underlying configuration for the remote UE.
  • the DU needs to allocate identifiers such as C-RNTI, local ID, or SL-RNTI to the remote UE, and configure the resource pool of the PC5 interface between the remote UE and the relay UE.
  • Step 604 The DU sends a user context modification response message to the CU, and the user context modification response message carries RRC configuration information.
  • the RRC configuration information of the relay UE can be carried in the user context modification response message and fed back to the CU, so that the CU generation can be sent to the relay UE RRC reconfiguration message.
  • the DU may add an information element (for example, CellGroupConfig-for remote UE) to the user context modification response message to carry the cell group configuration for the remote UE . Therefore, the DU can send the RRC configuration information of the relay UE and the RRC configuration information of the remote UE to the CU together in the user context modification response message.
  • an information element for example, CellGroupConfig-for remote UE
  • the user context modification response message is also encapsulated in the CU-DU interface message (for example, the F1 message in the 5G system), based on the identity of the relay UE on the CU-DU interface, through the communication between the DU and the CU The CU-DU interface is sent to the CU.
  • the CU-DU interface message for example, the F1 message in the 5G system
  • Step 605 The CU generates an RRC reconfiguration message.
  • the user context modification response message carries the RRC configuration information of the relay UE and the RRC configuration information of the remote UE.
  • the CU generates an RRC reconfiguration message for the relay UE according to the RRC configuration information of the relay UE, and generates an RRC reconfiguration message for the remote UE according to the RRC configuration information of the remote UE.
  • Step 606 the CU sends an RRC reconfiguration message.
  • the CU sends the RRC reconfiguration message of the relay UE to the relay UE through the DU, and forwards the RRC reconfiguration message of the remote UE to the remote UE through the DU and the relay UE.
  • RRC messages When RRC messages are transmitted between the CU and DU, they are all encapsulated in a downlink RRC information transmission (DL RCC message transfer) message or an uplink RRC information transmission (UL RCC message transfer) message for transmission.
  • RRC messages refer to messages related to RRC control, such as RRC connection request message, RRC connection establishment message, RRC recovery request message, RRC recovery message, RRC security mode completion message, RRC reconfiguration message, RRC connection completion Messages, RRC re-establishment messages, etc.
  • the cell structure of the downlink RRC information transmission message and the uplink RRC information transmission message is generally: the identity of the UE on the CU-DU interface, the SRB identity, and the RRC container (RRC-container).
  • the identifier of the UE on the CU-DU interface may include the CU side identifier and the DU side identifier of the CU-DU interface. It is used by the CU and DU to identify which UE the message is for, which is equivalent to establishing a connection between the CU and DU for the UE The channel for transmitting RRC messages.
  • the RRC container is used to carry specific RRC messages, and the SRB identifier is used to instruct the DU to send the RRC message to the UE through the logical channel (logical channel between the DU and the CU and the UE) corresponding to the SRB identifier, or for the CU to send the RRC message Sent to the PDCP entity corresponding to the SRB identifier.
  • the SRB identifier is used to instruct the DU to send the RRC message to the UE through the logical channel (logical channel between the DU and the CU and the UE) corresponding to the SRB identifier, or for the CU to send the RRC message Sent to the PDCP entity corresponding to the SRB identifier.
  • the CU When the CU sends the RRC reconfiguration message of the relay UE to the relay UE, the CU needs to encapsulate the PDCP layer outside the RRC reconfiguration message of the relay UE to obtain the downlink RRC information of the relay UE.
  • the CU also needs to continue to encapsulate adaptation information outside the PDCP layer, and the adaptation information may include the identifier of the relay UE.
  • the CU carries the obtained downlink RRC information in the RRC container of the downlink RRC information transmission message and sends it to the DU.
  • the CU-DU interface identifier carried in the downlink RRC information transmission message is the identifier of the relay UE on the CU-DU interface.
  • the DU After obtaining the downlink RRC information of the relay UE, the DU continues to encapsulate the RCL layer, MAC layer, and PHY layer for the downlink RRC message of the relay UE. That is, if adaptation information is encapsulated in the downlink RRC information, the DU encapsulates the RLC layer, MAC layer, and PHY layer outside the adaptation information. If there is no encapsulation adaptation information in the downlink RRC information, the DU encapsulates the RLC layer, MAC layer, and PHY layer outside the PDCP layer.
  • the DU sends the downlink RRC information encapsulating the RRC reconfiguration message of the relay UE to the relay UE through the logical channel corresponding to the SRB1 of the relay UE.
  • the relay UE After the relay UE obtains the RRC reconfiguration message of the relay UE from the downlink RRC information, it can learn the bearer identity of the relay UE, the relay UE and the remote UE2 according to the indication of the RRC reconfiguration message.
  • the relay service is provided for the remote UE2 subsequently, the data packet and the RRC message between the remote UE2 and the CU are forwarded based on the learned mapping relationship.
  • the CU When the CU sends the RRC reconfiguration message of the remote UE2 to the remote UE, the CU encapsulates the PDCP layer and adaptation information for the RRC reconfiguration message of the remote UE2 (that is, the RRC reconfiguration message encapsulates the PDCP layer, PDCP The outside of the layer encapsulates adaptation information) to obtain the downlink RRC information of the remote UE2.
  • the adaptation information is used to indicate that the currently transmitted RRC reconfiguration message is the RRC reconfiguration message of the remote UE2, and the adaptation information may include the identifier of the remote UE2 and the logical channel between the remote UE2 and the relay UE. Identification (assumed to be LCID4).
  • the adaptation information may also include the identifier of the remote UE2 and the identifier of the SRB of the remote UE2 (assuming the identifier of the SRB2 of the remote UE2). Then the CU carries the downlink RRC information of the remote UE2 in the RRC container of the downlink RRC information transmission message and sends it to the DU.
  • the remote UE2 Since the CU and DU have not established a context for the remote UE2, the remote UE2 does not have an identity on the CU-DU interface. Therefore, when sending the RRC reconfiguration message of the remote UE, the CU-DU interface identifier carried in the downlink RRC information transmission message used is still the identifier of the relay UE on the CU-DU interface.
  • the protocol stack of the relay UE and the CU adopts the above scheme 1 to set the adaptation layer, then in order for the relay UE to know that the downlink RRC message of the remote UE is encapsulated with adaptation information, the CU can encapsulate the downlink RRC information of the remote UE2.
  • a first indication is added to the downlink RRC information transmission message to indicate that the downlink RRC message of the remote UE2 is externally encapsulated with adaptation information.
  • the first indication may be an adaptation layer indication (adaptation layer indication) or a relay indication (relay indication).
  • the first indication is carried in the interaction message between the CU and the DU (for example, uplink/downlink RRC information transmission message, uplink/downlink GTP-U frame), and is used to indicate the current transmitted RRC message or data packet external
  • the package has adaptation information.
  • the DU after the DU obtains the downlink RRC information of the remote UE2 sent by the CU, when encapsulating the PHY layer, MAC layer, and RLC layer for the downlink RRC information of the remote UE2, the DU can transmit the first information carried in the message according to the downlink RRC information. Indication, a third indication is added to the PHY layer, MAC layer or RLC layer. Finally, the encapsulated downlink RRC information of the remote UE2 is sent to the relay UE.
  • the downlink RRC information sent by the DU to the relay UE includes the RRC reconfiguration message of the remote UE2, the PDCP layer encapsulated outside the RRC reconfiguration message, the adaptation information encapsulated outside the PDCP layer, and the information encapsulated outside the adaptation information.
  • the third indication is an indication that the relay UE or DU is added to the PHY layer, MAC layer, or RLC layer to indicate that the currently transmitted RRC message or data packet is encapsulated with adaptation information.
  • the relay UE After the relay UE receives the downlink RRC information of the remote UE2 sent by the DU, it obtains the third indication in the process of deleting the PHY layer, MAC layer, and RLC layer of the downlink RRC information, so that the relay UE can follow the third instruction Indicates that the downlink RRC information includes adaptation information. Then the relay UE reads the adaptation information after deleting the PHY layer, MAC layer, and RLC layer of the downlink RRC information, and determines that the RRC message encapsulated in the downlink RRC information is the RRC reconfiguration message of the remote UE2.
  • the relay UE sends the downlink RRC information to the remote UE2 through the logical channel LCID4. If the adaptation information carries the identifier of the remote UE2 and the identifier of the SRB2 of the remote UE2, the relay UE determines according to the mapping relationship shown in Table 1 indicated by the previously received RRC reconfiguration message of the relay UE The downlink RRC information is sent to the remote UE2 through the logical channel LCID4.
  • the downlink RRC information received by the relay UE from the DU includes the PHY layer, MAC layer, and RLC layer of the Uu interface between the relay UE and the DU. Then, when the relay UE sends the downlink RRC information to the remote UE2, it needs to delete the Uu interface PHY layer, MAC layer, and RLC layer, and re-encapsulate the PHY layer, MAC layer, and MAC layer of the PC5 interface between the relay UE and the remote UE2.
  • RLC layer
  • the CU does not need to add the first indication to the downlink RRC information transmission message carrying the downlink RRC information of the remote UE2, so the DU does not need to A third indication is added to the PHY layer, MAC layer, or RLC layer in the downlink RRC information.
  • the relay UE When the relay UE receives any piece of downlink RRC information, it will read the adaptation information in the downlink RRC information, determine which UE has received the downlink RRC message encapsulated in the downlink RRC information, and forward the downlink RRC according to the adaptation information information.
  • the remote UE2 requests the base station under the CU-DU architecture to establish an RRC connection, restore the RRC connection, or re-establish the RRC connection through the relay UE. After that, the remote UE2 can perform subsequent information exchange with the CU through the relay UE.
  • the remote UE2 when the remote UE2 sends an uplink RRC message to the CU, the remote UE2 encapsulates the PDCP layer and the RLC layer, MAC layer, and PHY layer of the PC5 interface for the uplink RRC message. And send the obtained uplink RRC information to the relay UE through the PC5 interface. Assume that the remote UE2 sends the uplink RRC information to the relay UE through the logical channel LCID4.
  • the relay UE After the relay UE deletes the RLC layer, MAC layer, and PHY layer of the PC5 interface in the uplink RRC information, the adaptation information and the RLC layer, MAC layer, and PHY layer of the Uu interface are sequentially encapsulated outside the PDCP layer in the uplink RRC information.
  • the adaptation information can carry the identifier of the remote UE2 and the LCID4.
  • the relay UE determines that the bearer identifier of the relay UE corresponding to the logical channel LCID4 is the SRB1 of the relay UE according to the mapping relationship shown in Table 1.
  • the relay UE sends the uplink RRC information to the DU through the logical channel between the relay UE and the DU corresponding to the SRB1 of the relay UE.
  • the relay UE determines the bearer identifier of the relay UE corresponding to the logical channel LCID4 (that is, the SRB1 of the relay UE) and the bearer identifier of the remote UE2 (that is, the SRB2 of the remote UE2) corresponding to the mapping relationship shown in Table 1.
  • the relay UE carries the identification of the remote UE2 and the identification of the SRB2 of the remote UE2 in the adaptation information. Then the relay UE sends the uplink RRC information to the DU through the logical channel between the relay UE and the DU corresponding to the SRB1 of the relay UE.
  • the relay UE can send the uplink RRC information to the DU in the RLC layer, A third indication is added to the MAC layer or the PHY layer to indicate that the uplink RRC message is externally encapsulated with adaptation information, so that the CU reads the adaptation information when receiving the uplink RRC information to determine the uplink RRC message in the uplink RRC information It's remote UE2.
  • the DU After receiving the uplink RRC information, the DU deletes the PHY layer, MAC layer, and RLC layer of the uplink RRC information. Then, according to the third instruction, carry the first instruction in the uplink RRC information transmission message to be sent to the CU, and carry the uplink RRC message and the PDCP layer and adaptation information encapsulated outside the uplink RRC message in the uplink RRC information transmission message In the RRC container, the uplink RRC information transmission message is finally sent to the CU.
  • the uplink RRC information transmission message also carries the identifier of the relay UE on the CU-DU interface.
  • the CU After receiving the uplink RRC information, the CU reads the adaptation information for reading the uplink RRC information according to the first indication carried in the uplink RRC information transmission message. Exemplarily, if the adaptation information carries the identification of the remote UE2 and the LCID4, the CU determines that the SRB of the remote UE2 corresponding to the LCID4 is the SRB2 of the remote UE2. Then the CU sends the uplink RRC information to the PDCP entity corresponding to the SRB2 of the remote UE2. If the adaptation information carries the identification of the remote UE2 and the identification of the SRB2 of the remote UE2, the CU may directly send the uplink RRC information to the PDCP entity corresponding to the SRB2 of the remote UE2.
  • the relay UE does not need to add the second layer to the PHY layer, MAC layer or RLC layer when sending the uplink RRC message of the remote UE.
  • the DU does not need to add the first indication to the uplink RRC information transmission message carrying the uplink RRC message.
  • the CU When the CU receives any uplink RRC information, it will read the adaptation information in the uplink RRC information, determine which UE the uplink RRC message encapsulated in the uplink RRC information is received, and send it to the SRB corresponding to the UE according to the adaptation information
  • the PDCP entity sends an uplink RRC message.
  • the encapsulated adaptation information may include the identity of the relay UE.
  • the specific process can refer to the above-mentioned process of the CU sending the RRC reconfiguration message of the remote UE2 to the remote UE2, which will not be repeated here.
  • the remote UE2 For the user plane data transmission process between the remote UE2 and the CU, when the remote UE2 sends an uplink data packet to the CU, the remote UE2 encapsulates the PDCP layer and the RLC layer, MAC layer and PHY layer of the PC5 interface for the uplink data packet, and Send the obtained uplink data information to the relay UE. Assume that the remote UE2 sends the uplink data information to the relay UE through the logical channel LCID5.
  • the relay UE After the relay UE deletes the RLC layer, MAC layer, and PHY layer of the PC5 interface in the uplink data information, it sequentially encapsulates the adaptation information and the RLC layer, MAC layer, and PHY layer of the Uu interface outside the PDCP layer in the uplink data information.
  • the adaptation information is used to indicate that the uplink data packet in the uplink data information belongs to the remote UE2, and the adaptation information may carry the identifier of the remote UE2 and the LCID5.
  • the relay UE determines, according to the mapping relationship shown in Table 1, that the bearer identifier of the relay UE corresponding to the logical channel LCID5 is the DRB3 of the relay UE.
  • the relay UE sends the uplink data information to the DU through the logical channel between the relay UE and the DU corresponding to the DRB3 of the relay UE.
  • the relay UE determines the bearer identity of the relay UE (ie DRB3 of the relay UE) and the bearer identity of the remote UE2 (ie DRB1 of the remote UE2) corresponding to the logical channel LCID5 according to the mapping relationship shown in Table 1.
  • the relay UE carries the identification of the remote UE2 and the identification of the DRB1 of the remote UE2 in the adaptation information. Then the relay UE sends the uplink data information to the DU through the logical channel between the relay UE and the DU corresponding to the DRB3 of the relay UE.
  • the relay UE can send the uplink data information to the DU in the RLC
  • a third indication is added to the layer, MAC layer, or PHY layer to indicate that the uplink data information includes adaptation information, so that the CU reads the adaptation information when receiving the uplink data information to determine that the uplink data information is encapsulated
  • the uplink data packet is remote UE2.
  • the DU After the DU receives the uplink data information, it deletes the PHY layer, MAC layer and RLC layer of the uplink data information. Then the remaining uplink data packet and the PDCP layer and adaptation information encapsulated outside the uplink data packet are carried in the uplink GTP-U frame and sent to the CU.
  • the DU since the CU and DU have not established a context for the remote UE2, that is, the remote UE2 does not have GTP-U tunnel resources. Therefore, the DU needs to encapsulate the uplink data information in the uplink GTP-U frame of the GTP-U tunnel corresponding to the DRB3 of the relay UE. That is, the uplink GTP-U frame carries the tunnel endpoint information of the GTP-U tunnel corresponding to the DRB3 of the relay UE.
  • the DU also needs to add a first indication to the uplink GTP-U frame according to the third indication carried in the PHY layer, MAC layer, or RLC layer of the uplink data information, so as to indicate the uplink data of the CU.
  • the information includes adaptation information.
  • the CU After receiving the uplink data information, the CU reads the adaptation information of the uplink data information according to the first indication carried in the uplink GTP-U frame. Exemplarily, if the adaptation information carries the identifier of the remote UE2 and LCID5, then the CU determines that the DRB of the remote UE2 corresponding to the LCID5 is the DRB1 of the remote UE2. Then the CU sends the uplink data information to the PDCP entity corresponding to the DRB1 of the remote UE2. If the adaptation information carries the identifier of the remote UE2 and the identifier of the DRB1 of the remote UE2, the CU can directly send the uplink data information to the PDCP entity corresponding to the DRB1 of the remote UE2.
  • the relay UE does not need to add the second layer to the PHY layer, MAC layer or RLC layer when sending uplink data information of the remote UE.
  • the DU does not need to add the first indication to the uplink GTP-U frame that carries the uplink data information.
  • the CU When the CU receives any piece of uplink data information, it will read the adaptation information in the uplink data information, determine which UE the uplink data packet in the received uplink data information belongs to, and assign the DRB corresponding to the UE according to the adaptation information.
  • the PDCP entity sends uplink data packets.
  • the encapsulated adaptation information may include the identity of the relay UE.
  • the CU When the CU sends a downlink data packet to the remote UE2, the CU encapsulates the PDCP layer and adaptation information for the downlink data packet to obtain the downlink data information of the remote UE2.
  • the adaptation information includes the identifier of the remote UE2 and the identifier of the logical channel between the remote UE2 and the relay UE (assumed to be LCID5).
  • the adaptation information may also include the identifier of the remote UE2 and the identifier of the DRB of the remote UE2 (assuming the identifier of the DRB1 of the remote UE2). Then the CU carries the downlink data information of the remote UE2 in the downlink GTP-U frame and sends it to the DU.
  • the CU needs to determine the identity of the DBR of the relay UE corresponding to LCID5 or LCID5 and the identity of the DRB1 of the remote UE2, that is, the identity of the DRB3 of the relay UE . Then the downlink data information is encapsulated in the downlink GTP-U frame of the GTP-U tunnel corresponding to the DRB3 of the relay UE and sent to the DU. That is, the downlink GTP-U frame carries the tunnel endpoint information of the GTP-U tunnel corresponding to the DRB3 of the relay UE.
  • the CU can carry the first in the downlink GTP-U frame.
  • An indication is used to indicate that the downlink data packet of the remote UE2 is encapsulated with adaptation information, so that the relay UE can read the adaptation information and perform corresponding forwarding operations.
  • the CU may add the first indication to the frame header of the downlink GTP-U frame whose type is downlink user data (DL user data).
  • the DU After receiving the downlink GTP-U frame, the DU obtains the downlink data information generated by the CU for the remote UE2. Then encapsulate the PHY layer, MAC layer, and RLC layer for the downlink data information, and add a third instruction to the PHY layer, MAC layer, or RLC layer according to the first instruction carried in the downlink GTP-U frame. Finally, the encapsulated downlink data information is sent to the relay UE.
  • the relay UE After the relay UE receives the downlink data information sent by the DU, it deletes the PHY layer, MAC layer, and RLC layer of the Uu interface encapsulated by the DU in the downlink data information, and determines that there is adaptation information in the downlink data information according to the third instruction .
  • the relay UE reads the adaptation information to determine that the downlink data packet encapsulated in the downlink data information is the downlink data packet of the remote UE2.
  • the relay UE deletes the adaptation information, and sequentially encapsulates the PHY layer and MAC layer of the PC5 interface outside the PDCP layer in the downlink data information. After layer and RLC layer, the downlink data information is sent to the remote UE2 through the logical channel LCID5 between the remote UE and the relay UE.
  • the relay UE determines according to the mapping relationship shown in Table 1 indicated by the previously received RRC reconfiguration message of the relay UE.
  • the downlink data information is sent to the remote UE2 through the logical channel LCID5 between the remote UE2 and the relay UE.
  • the CU does not need to add the first indication to the downlink GTP-U frame carrying the downlink data packet of the remote UE2, so the DU also needs A third indication is added to the RLC layer, MAC layer or PHY layer of the downlink data packet.
  • the relay UE When the relay UE receives any downlink data information, it will read the adaptation information in the downlink data information, determine which UE the downlink data packet encapsulated in the downlink data information is received, and forward the downlink data according to the adaptation information information. In this case, if the CU sends a downlink data packet of the relay UE to the relay UE, the encapsulated adaptation information may carry the identity of the relay UE.
  • the above communication method provided for this application is used to implement a UE-to-Network relay communication process based on the CU-DU architecture, when the adaptation layer is deployed in the protocol stack of the CU.
  • the DU protocol stack is The communication principle of UE-to-Network relay when the adaptation layer is deployed.
  • FIG 7 is a possible user plane protocol stack between the remote UE2, the relay UE, the CU, and the DU in the UE-to-Network relay communication system.
  • the adaptation layer is deployed in the DU protocol stack.
  • Fig. 8 is a possible control plane protocol stack between the remote UE2, the relay UE, the CU, and the DU in the UE-to-Network relay communication system.
  • the adaptation layer is deployed in the DU protocol stack.
  • the third solution is that when transmitting the data packet/RRC message of the relay UE, the protocol stack of the DU and the relay UE does not include the adaptation layer, and when transmitting the data packet/RRC message of the remote UE, the DU and the relay UE
  • the adaptation layer will be included in the protocol stack. That is, for the uplink, when the relay UE sends an uplink data packet/uplink RRC message, if the relay UE sends its own uplink data packet/uplink RRC message, the relay UE does not need to send the uplink data packet/uplink RRC message.
  • RRC message encapsulates adaptation information.
  • the relay UE needs to encapsulate adaptation information for the uplink data packet/uplink RRC message to indicate to the DU that the uplink data packet/uplink RRC message is from the remote UE .
  • the DU sends a downlink data packet/downlink RRC message, if it is sending a relay UE downlink data packet/downlink RRC message, the DU does not need to be the downlink data packet/downlink RRC message Package adaptation information.
  • the DU needs to encapsulate adaptation information for the downlink data packet/downlink RRC message to indicate to the relay UE that the downlink data packet/downlink RRC message is from the remote UE . Since the adaptation layer may or may not exist, it is necessary for the relay or base station to indicate whether the counterparty adaptation layer exists when sending each data packet/RRC message.
  • the fourth solution is that the protocol stack of the DU and the relay UE always includes an adaptation layer. For uplink, whether the relay UE sends its own data packet/RRC message or forwards the data packet/RRC message of the remote UE, the relay UE will encapsulate the adaptation information for the sent data packet/RRC message for the DU to know Whether the data packet/RRC message sent by the relay UE belongs to the remote UE or the relay UE itself.
  • the DU For the downlink, whether the DU sends data packets/RRC messages to remote UEs through the relay UE, or directly sends data packets/RRC messages to the relay UE, the DU encapsulates the configuration information for the sent data packets/RRC messages for use Then the UE knows whether the data packet/RRC message sent by the DU is sent to the relay UE or to the remote UE.
  • the relay or base station since the adaptation layer always exists, the relay or base station does not need to indicate whether the counterparty adaptation layer exists when sending each data packet/RRC message.
  • the DU is sending to the CU the packet/RRC message sent by the relay UE.
  • the data packet/RRC message is a relay UE or which remote UE.
  • Figure 9 it is a schematic diagram of the communication principle of UE-to-Network relay based on the protocol stacks shown in Figures 7 and 8.
  • the DU sends the data packet to the GTP-U tunnel through the relay UE CU, the CU transmits the data packet to the PDCP entity corresponding to the DRB of the relay UE.
  • the DU sends the RRC message to the CU through the identifier of the relay UE on the CU-DU interface, and the CU transmits the RRC message to the PDCP entity of the relay UE. If the data packet/RRC message is from the remote UE1 (the communication route can be referred to the dotted line shown in FIG. 9).
  • the DU For a data packet, if the DU determines that the data packet is a DRB data packet of the remote UE1 according to the adaptation information of the adaptation layer, the DU sends the data packet to the CU through the GTP-U tunnel corresponding to the DRB of the remote UE1. The CU transmits the data packet to the PDCP entity corresponding to the DRB of the remote UE1. For the RRC message, if the DU judges that the RRC message is an SRB data packet of remote UE1 according to the adaptation information of the adaptation layer, the DU sends the RRC message to the CU through the identifier of the remote UE1 on the CU-DU interface. The RRC message is transmitted to the PDCP entity corresponding to the SRB of the remote UE1.
  • the adaptation layer when the adaptation layer is deployed on the DU side, when a remote UE requests the CU and DU to establish an RRC connection through the relay UE, or requests to restore the RRC connection, or requests to re-establish the RRC connection, the CU and DU need
  • the context is established for the remote UE, and the context of the relay UE needs to be modified at the same time, so that the relay UE can provide relay services for the remote UE.
  • FIG. 10 is a flowchart of an embodiment of a communication method provided by this application, which mainly describes the UE-to-Network relay communication process when the adaptation layer is deployed on the DU side.
  • the method includes:
  • Step 1001 The CU generates a user context modification request message.
  • the user context modification request message is used to request the DU to modify the context of the relay UE.
  • the user context modification request message carries the identifier of the remote UE, the bearer identifier of the relay UE, and the The bearer identifier of the relay UE has a mapping relationship between the logical channel identifier, the bearer identifier of the relay UE is the identifier of the bearer between the relay UE and the CU, and the logical channel is between the remote UE and the relay UE. Logical channel between.
  • Step 1002 The CU sends a user context modification request message to the DU.
  • Step 1003 The DU generates RRC configuration information of the relay UE according to the identification of the remote UE, the bearer identification of the relay UE, and the identification of the logical channel.
  • the RRC configuration information of the relay UE includes the identification of the remote UE and the identification of the relay UE.
  • Step 1004 The DU sends a user context modification response message to the CU.
  • the user context modification response message carries the RRC configuration information of the relay UE.
  • steps 1001-1004 can be referred to in the above steps 601-604, the CU and DU modify the context of the relay UE and the process of generating RRC configuration information, which will not be repeated here.
  • Step 1005 The CU generates an RRC reconfiguration message of the relay UE according to the RRC configuration information of the relay UE.
  • Step 1006 The CU sends an RRC reconfiguration message of the relay UE to the relay UE.
  • the CU when the CU sends the RRC reconfiguration message of the relay UE to the relay UE, the CU needs to encapsulate the PDCP layer outside the RRC reconfiguration message of the relay UE to obtain the downlink RRC information of the relay UE. Then the CU carries the obtained downlink RRC information in the RRC container of the downlink RRC information transmission message and sends it to the DU.
  • the CU-DU interface identifier carried in the downlink RRC information transmission message is the identifier of the relay UE on the CU-DU interface.
  • the protocol stack of the relay UE and the DU adopts the above scheme 3 to set the adaptation layer, then after the DU obtains the downlink RRC information of the relay UE sent by the CU, the RLC layer can be sequentially encapsulated outside the PDCP layer in the downlink RRC information , MAC layer and PHY layer.
  • the protocol stack of the relay UE and the DU adopts the above scheme 4 to set the adaptation layer, then after the DU obtains the downlink RRC information of the relay UE sent by the CU, it can sequentially encapsulate the adaptation outside the PDCP layer in the downlink RRC information Information, RLC layer, MAC layer and PHY layer.
  • the adaptation information may include the identifier of the relay UE, which is used to indicate that the RRC reconfiguration message encapsulated in the downlink RRC information is for the relay UE.
  • the DU sends the encapsulated downlink RRC information to the relay UE through the logical channel (logical channel between the relay UE and the CU) corresponding to the SRB1 of the relay UE.
  • the relay UE After the relay UE obtains the RRC reconfiguration message of the relay UE from the downlink RRC information, it can learn the bearer identity of the relay UE, the relay UE and the remote UE2 according to the indication of the RRC reconfiguration message.
  • the relay service is provided for the remote UE2 subsequently, the data packet and the RRC message between the remote UE2 and the CU are forwarded based on the learned mapping relationship.
  • Step 1007 The CU sends a user context establishment request message to the DU.
  • the CU after receiving a request message from a remote UE (for example, an RRC connection request message, an RRC re-establishment request message, or an RRC recovery request message), the CU can generate a user context establishment request message to request the DU for the The remote UE establishes the context.
  • a request message from a remote UE for example, an RRC connection request message, an RRC re-establishment request message, or an RRC recovery request message
  • the CU can generate a user context establishment request message to request the DU for the The remote UE establishes the context.
  • the user context establishment request message may include the identifier of the remote UE, the identifier of the CU-DU interface allocated by the CU to the remote UE, the identifier of the relay UE, the SRB list and the DRB list added by the CU for the remote UE request, and the The mapping relationship between the bearer identifier of the remote UE and the logical channel.
  • the identifier of the remote UE may be the identifier of the remote UE carried in the request message of the remote UE received by the CU.
  • the identifier of the remote UE may be the L2ID of the remote UE, or the identifier of the PC5 interface of the remote UE between the remote UE and the relay UE, or a combination of the L2ID of the remote UE and the identifier of the PC5 interface.
  • the CU determines that it is the request of the remote UE through the received identifier of the remote UE, and the relay UE that forwards the request message serves as a relay to provide a relay service for the remote UE. Therefore, the CU needs to determine each logical channel (logical channel between the remote UE and the relay UE) to determine the corresponding bearer for the remote UE, so that the DU can establish an uplink for the remote UE.
  • the SRB list may include the identification of each SRB that the CU requests for the remote UE to be added.
  • the DRB list may include the identification of each DRB requested by the CU for the remote UE to be added, and the TEID on the CU side of the GTP-U tunnel corresponding to each DRB.
  • the bearer identifier of the remote UE is the identifier of the bearer between the remote UE and the CU, that is, the identifier of the SRB in the SRB list and the identifier of the DRB in the DRB list.
  • the logical channel is the logical channel of the side link between the remote UE and the relay UE, or the logical channel of the PC5 interface between the remote UE and the relay UE.
  • the remote UE and the relay UE adopt direct transmission through the logical channel. Information exchange in a way.
  • the user context establishment request message includes the identifier of the remote UE2, the identifier on the CU-DU interface allocated by the CU for the remote UE2, and the SRB list requested by the CU for the remote UE2 (including the SRB1 and SRB1 of the remote UE2)
  • the user context establishment request message also carries a second indication, and the second indication is used to instruct the DU to send the downlink data information or downlink RRC information of the remote UE to the relay UE.
  • Add adaptation information to indicate that the downlink data information or downlink RRC information is for the remote UE.
  • the user context establishment request message can be encapsulated in a CU-DU interface message and sent to the DU.
  • the user context establishment request message can be encapsulated in an F1 message, and the CU sends it to the DU through the F1 interface with the DU to request the DU to establish the context of the remote UE.
  • Step 1008 The DU generates RRC configuration information of the remote UE according to the mapping relationship between the identifier of the relay UE, the identifier of the remote UE, the bearer identifier of the remote UE and the logical channel.
  • the DU After receiving the user context establishment request message, the DU confirms the CU-DU interface identifier of the remote UE assigned to the remote UE by the CU, the identifier of the relay UE, the SRB list and DRB list requested to be added, and the bearer identifier and logic of the remote UE The mapping relationship between channels. And for each DRB in the DRB list, the TEID on the DU side of the corresponding GTP-U tunnel and the DU side identifier of the UE allocated for the UE on the CU-DU interface are allocated to complete the context establishment of the remote UE.
  • the DU can also provide underlying configuration for the remote UE, including allocating identifiers such as C-RNTI, local ID or SL-RNTI for the remote UE, and configuring the remote UE and relay UE Low-level information such as the resource pool of the PC5 interface.
  • the DU allocates the DU side identifier of the CU-DU interface for the remote UE and the TEID of the corresponding GTP-U tunnel based on the information carried in the user context establishment request message and the information carried in the user context request message.
  • the underlying information generates the RRC configuration information of the remote UE, for example, the cell group configuration information for the remote UE.
  • Step 1009 The DU sends a user context setup response (UE context setup response) message to the CU.
  • UE context setup response UE context setup response
  • the DU encapsulates the RRC configuration information of the remote UE into a user context establishment response message and feeds it back to the CU.
  • the context establishment of the remote UE is completed.
  • Step 1010 The CU generates an RRC reconfiguration message of the remote UE according to the RRC configuration information of the remote UE.
  • Step 1011 The CU sends an RRC reconfiguration message of the remote UE to the remote UE.
  • the CU when the CU sends the RRC reconfiguration message of the remote UE2 to the remote UE2, the CU encapsulates the PDCP layer for the RRC reconfiguration message of the remote UE2 to obtain the downlink RRC information of the remote UE2. Then the downlink RRC information is carried in the RRC container of the downlink RRC information transmission message and sent to the DU.
  • the remote UE2 since the CU and DU establish a context for the remote UE2, the remote UE2 has an identity on the CU-DU interface. Therefore, when sending the RRC reconfiguration message of the remote UE2, the CU-DU interface identifier carried in the downlink RRC information transmission message is the identifier of the remote UE2 on the CU-DU interface.
  • the DU After receiving the downlink RRC information transmission message, the DU obtains the downlink RRC information of the remote UE2, and then sequentially encapsulates the adaptation information, the RLC layer, the MAC layer, and the PHY layer outside the PDCP layer in the downlink RRC information. Finally, the encapsulated downlink RRC information of the remote UE2 is sent to the relay UE through the logical channel corresponding to the SRB1 of the relay UE (the logical channel between the relay UE and the DU).
  • the adaptation information is used to indicate that the RRC reconfiguration message encapsulated in the downlink RRC information is the RRC reconfiguration message of the remote UE2, and the adaptation information may include the identifier of the remote UE2 and the communication between the remote UE2 and the relay UE.
  • the identifier of the logical channel (assumed to be LCID3).
  • the adaptation information may also include the identifier of the remote UE2 and the bearer identifier of the remote UE2 (assumed to be the identifier of the SRB1 of the remote UE2).
  • the protocol stack of the relay UE and the DU adopts the above scheme 3 to set the adaptation layer, then in order for the relay UE to know that the downlink RRC information sent by the DU is encapsulated with adaptation information, the DU can be in the RLC layer, MAC layer or PHY layer A third indication is added to indicate that the downlink RRC information includes adaptation information, so that the relay UE can read the adaptation information in the downlink RRC information, and then forward the RRC reconfiguration of the remote UE2 based on the read adaptation information news.
  • the relay UE After the relay UE receives the downlink RRC information sent by the DU, it obtains the third indication in the process of deleting the PHY layer, MAC layer, and RLC layer of the Uu interface encapsulated by the DU in the downlink RRC information, so that the relay UE obtains the third indication according to the third Indicates that the downlink RRC information includes adaptation information. Then, after the relay UE deletes the PHY layer, MAC layer, and RLC part of the Uu interface in the downlink RRC information, it reads the adaptation information and determines that the RRC reconfiguration message encapsulated in the downlink RRC information is the RRC reconfiguration message of the remote UE2. Configuration message.
  • the relay UE is deleting the adaptation information and encapsulating the PHY layer and MAC layer of the PC5 interface outside the PDCP layer in the downlink RRC information After the RLC part, the downlink RRC information is sent to the remote UE2 through the logical channel LCID3. If the adaptation information carries the identifier of the remote UE2 and the identifier of the SRB1 of the remote UE2, the relay UE determines according to the mapping relationship shown in Table 1 indicated by the RRC reconfiguration message of the relay UE received before The logical channel LCID3 sends the downlink RRC information of the remote UE2 to the remote UE2.
  • the DU does not need to add the RLC layer, MAC layer or PHY layer when sending downlink RRC information of remote UE2 to the middle UE.
  • the third instruction When the relay UE receives any piece of downlink RRC information, it will read the adaptation information in the downlink RRC information, determine which UE has received the downlink RRC message encapsulated in the downlink RRC information, and forward the downlink RRC according to the adaptation information information.
  • the remote UE2 requests the base station under the CU-DU architecture to establish an RRC connection, restore the RRC connection, or re-establish the RRC connection through the relay UE. After that, the remote UE2 can perform subsequent information exchange with the CU through the relay UE.
  • the remote UE2 when the remote UE2 sends an uplink RRC message to the CU, the remote UE2 encapsulates the PDCP layer and the RLC layer, MAC layer, and PHY layer of the PC5 interface for the uplink RRC message, and Send the obtained uplink RRC information to the relay UE.
  • the uplink RRC message is the RRC message transmitted on SRB1 of the remote UE2
  • the remote UE2 can be based on the remote UE2’s bearer identifier indicated by the previously received RRC reconfiguration message and the logical channel between the remote UE2 and the relay UE.
  • the mapping relationship between the identities determines that the RRC message transmitted on the SRB1 of the remote UE2 can be sent through the logical channel LCID3. Then the remote UE2 can send the uplink RRC information to the relay UE through the logical channel LCID3.
  • the relay UE After the relay UE deletes the RLC layer, MAC layer, and PHY layer of the PC5 interface in the uplink RRC information, the adaptation information and the RLC layer, MAC layer, and PHY layer of the Uu interface are sequentially encapsulated outside the PDCP layer in the uplink RRC information.
  • the adaptation information can carry the identifier of the remote UE2 and LCID3.
  • the relay UE determines, according to the mapping relationship shown in Table 1, that the bearer identifier of the relay UE corresponding to the logical channel LCID3 is the SRB1 of the relay UE.
  • the relay UE sends the uplink RRC information to the DU through the logical channel between the relay UE and the DU corresponding to the SRB1 of the relay UE.
  • the relay UE determines the bearer identifier of the relay UE (ie SRB1 of the relay UE) and the bearer identifier of the remote UE2 (ie SRB1 of the remote UE2) corresponding to the logical channel LCID3 according to the mapping relationship shown in Table 1.
  • the relay UE carries the identification of the remote UE2 and the identification of the SRB1 of the remote UE2 in the adaptation information. Then the relay UE sends the uplink RRC information to the DU through the logical channel between the relay UE and the DU corresponding to the SRB1 of the relay UE.
  • the relay UE can use the RLC layer of the Uu interface of the uplink RRC message, A third indication is added to the MAC layer or the PHY layer to indicate that the uplink RRC message is encapsulated with adaptation information, so that the DU reads the adaptation information when receiving the uplink RRC information to determine the uplink RRC encapsulated in the uplink RRC information
  • the message is for remote UE2.
  • the DU After receiving the uplink RRC information, the DU determines that the uplink RRC information includes adaptation information according to the third indication carried in the PHY layer, MAC layer, or RLC layer of the uplink RRC information. After deleting the PHY layer, MAC layer and RLC layer of the uplink RRC information, the DU reads the adaptation information of the uplink RRC information.
  • the DU can determine the identifier of the SRB2 of the relay UE and/or the identifier of the SRB of the remote UE2 corresponding to LCID3 according to the mapping relationship shown in Table 1. , That is, the identifier of the SRB1 of the remote UE2. If the adaptation information carries the identifier of the remote UE2 and the identifier of the remote UE's SRB1, the DU can directly obtain the identifier of the remote UE's SRB1 from the adaptation information.
  • the DU encapsulates the uplink RRC message, the PDCP layer encapsulated outside the uplink RRC message, the identifier of the remote UE2 on the CU-DU interface, and the identifier of the SRB1 of the remote UE2 in an uplink RRC information transmission message and sends it to the CU.
  • the CU After receiving the uplink RRC information transmission message, the CU obtains the uplink RRC information of the remote UE2 carried, and sends the uplink RRC information to the remote UE2 according to the identifier of the SRB1 of the remote UE2 carried in the uplink RRC information transmission message.
  • the PDCP entity corresponding to SRB1.
  • the relay UE does not need to use the PHY layer, MAC layer or RLC layer of the Uu interface when sending the uplink RRC message of the remote UE.
  • the DU When the DU receives any uplink RRC information sent by the relay UE, it will read the adaptation information in the uplink RRC information, and determine which UE has received the uplink RRC message encapsulated in the uplink RRC information.
  • the relay UE sends its own uplink RRC message the externally encapsulated adaptation information may include the identity of the relay UE.
  • the specific process can refer to the process in which the CU sends the RRC reconfiguration message of the remote UE2 to the remote UE2 in step 1011, which will not be repeated here.
  • the remote UE2 For the user plane data transmission process between the remote UE2 and the CU, when the remote UE2 sends an uplink data packet to the CU, the remote UE2 encapsulates the PDCP layer and the RLC layer, MAC layer, and PHY layer of the PC5 interface for the uplink data packet.
  • the obtained uplink data information is sent to the relay UE.
  • the remote UE2 uses the mapping relationship between the bearer identifier of the remote UE2 and the identifier of the logical channel indicated by the previously received RRC reconfiguration message to determine that the logical channel is passed LCID5 sends the uplink data information to the relay UE.
  • the relay UE After the relay UE deletes the RLC layer, MAC layer, and PHY layer of the PC5 interface in the uplink data information, it sequentially encapsulates the adaptation information and the RLC layer, MAC layer, and PHY layer of the Uu interface outside the PDCP layer in the uplink data information.
  • the adaptation information is used to indicate that the uplink data packet in the uplink data information belongs to the remote UE2, and the adaptation information may carry the identifier of the remote UE2 and the LCID5.
  • the relay UE determines, according to the mapping relationship shown in Table 1, that the bearer identifier of the relay UE corresponding to the logical channel LCID5 is the DRB3 of the relay UE.
  • the relay UE sends the uplink data information to the DU through the logical channel between the relay UE and the DU corresponding to the DRB3 of the relay UE.
  • the relay UE determines the bearer identity of the relay UE (ie DRB3 of the relay UE) and the bearer identity of the remote UE2 (ie DRB1 of the remote UE2) corresponding to the logical channel LCID5 according to the mapping relationship shown in Table 1.
  • the relay UE carries the identification of the remote UE2 and the identification of the DRB1 of the remote UE2 in the adaptation information. Then the relay UE sends the uplink data information to the DU through the logical channel between the relay UE and the DU corresponding to the DRB3 of the relay UE.
  • the relay UE can use the Uu interface of the uplink data packet
  • a third indication is added to the RLC layer, MAC layer or PHY layer to indicate that the uplink data packet is externally encapsulated with adaptation information, so that the DU reads the adaptation information when receiving the uplink data information to determine the uplink data
  • the uplink data packet in the information is from the remote UE2.
  • the DU After receiving the uplink data information, the DU determines that the uplink data information includes adaptation information according to the third indication carried in the PHY layer, MAC layer, or RLC layer of the uplink data information.
  • the DU reads the adaptation information of the uplink data information, and determines that the uplink data packet encapsulated in the uplink data information is of the remote UE2. If the adaptation information carries the identification of the remote UE2 and LCID5, then the DU can determine the identification of the DRB3 of the relay UE and the identification of the DRB of the remote UE2 corresponding to LCID5 according to the mapping relationship shown in Table 1. The ID of DRB1.
  • the DU carries the deleted PHY layer, MAC layer, RLC layer, and uplink data information (that is, including the uplink data packet and the PDCP layer encapsulated outside the uplink data packet) in the uplink GTP-U frame corresponding to DRB1 of the remote UE2.
  • the uplink GTP-U frame carries the tunnel endpoint information of the GTP-U tunnel corresponding to the DRB1 of the remote UE2.
  • the DU can directly carry the uplink data information with the PHY layer, the MAC layer, the RLC layer and the adaptation information deleted in the uplink corresponding to the DRB1 of the remote UE2 Sent to the CU in the GTP-U frame.
  • the relay UE does not need to add a second layer to the PHY layer, MAC layer or RLC layer when sending uplink data packets of the remote UE.
  • the DU will read the adaptation information in the uplink data information and determine which UE belongs to the uplink data packet encapsulated in the received uplink data information.
  • the externally encapsulated adaptation information may include the identity of the relay UE.
  • the CU After receiving the uplink GTP-U frame, the CU obtains uplink data information. Then the uplink data information is sent to the PDCP entity corresponding to the DRB1 of the remote UE2.
  • the CU When the CU sends a downlink data packet to the remote UE2, the CU encapsulates the PDCP layer for the downlink data packet to obtain downlink data information. Assuming that the downlink data packet is a data packet transmitted by the DRB1 of the remote UE2, the CU carries the downlink data information in the downlink GTP-U frame corresponding to the DRB1 of the remote UE2 and sends it to the DU, that is, the downlink GTP-U frame carries the remote The tunnel endpoint information of the GTP-U tunnel corresponding to the DRB1 of the UE2.
  • the DU After receiving the downlink GTP-U frame, the DU obtains the carried downlink data information. Then, the adaptation information and the RLC layer, MAC layer, and PHY layer of the Uu interface are sequentially encapsulated outside the PDCP layer in the downlink data information. Finally, the DU sends the encapsulated downlink RRC information of the remote UE2 to the relay UE through the logical channel corresponding to the DRB3 of the relay UE (the logical channel between the relay UE and the DU).
  • the adaptation information is used to indicate that the downlink data packet encapsulated in the downlink data information is a downlink data packet of the remote UE2, and the adaptation information may include the identifier of the remote UE2 and the identifier of the logical channel.
  • the identifier of the logical channel is LCID5 corresponding to DRB1 of remote UE2.
  • the configuration information generated by the DU for the relay UE includes the mapping relationship between the bearer identifier of the relay UE, the bearer identifier of the remote UE2, and the identifier of the logical channel between the relay UE and the remote UE2
  • the adaptation information may also include the identifier of the remote UE2 and the identifier of the DRB1 of the remote UE2.
  • the protocol stack of the relay UE and the DU adopts the above scheme 3 to set the adaptation layer, then in order for the relay UE to learn that the downlink data packet of the remote UE2 is encapsulated with adaptation information, the DU can be used in the RLC layer and MAC layer of the Uu interface. Or a third indication is added to the PHY layer to indicate to the relay UE that the downlink data packet is encapsulated with adaptation information, so that the relay UE can read the adaptation information.
  • the relay UE After the relay UE receives the downlink data information sent by the DU, it deletes the PHY layer, MAC layer, and RLC layer of the Uu interface encapsulated by the DU in the downlink data information, and determines that there is adaptation information in the downlink data information according to the third instruction .
  • the relay UE reads the adaptation information to determine that the downlink data packet encapsulated in the downlink data information is the downlink data packet of the remote UE2.
  • the relay UE deletes the adaptation information, and sequentially encapsulates the PHY layer and MAC layer of the PC5 interface outside the PDCP layer in the downlink data information. After the layer and RLC layer, the downlink data information is sent to the remote UE2 through the logical channel LCID5 between the relay UE and the remote UE2.
  • the relay UE determines according to the mapping relationship shown in Table 1 indicated by the previously received RRC reconfiguration message of the relay UE.
  • the downlink data information is sent to the remote UE2 through the logical channel LCID5 between the remote UE2 and the relay UE.
  • the DU does not need to add a third indication to the PHY layer, MAC layer or RLC layer of the downlink data packet of the remote UE2.
  • the relay UE When the relay UE receives any downlink data information, it will read the adaptation information in the downlink data information, determine which UE the downlink data packet in the received downlink data information belongs to, and forward the downlink data information according to the adaptation information .
  • the encapsulated adaptation information may carry the identifier of the relay UE to indicate that the downlink data information is for the relay UE.
  • the above communication method provided for this application is used to implement a UE-to-Network relay communication process based on the CU-DU architecture and when the adaptation information is deployed on the DU side.
  • the communication device 1100 includes a processing unit 1101 and a communication unit 1102.
  • the communication device 1100 further includes a storage unit 1103.
  • the processing unit 1101, the communication unit 1102, and the storage unit 1103 are connected through a communication bus 1104.
  • the processing unit 1101 may include at least one processor, where the processor may include at least one of the following types: a general-purpose central processing unit (Central Processing Unit, CPU), a digital signal processor (Digital Signal Processor, DSP), a microprocessor, Application-Specific Integrated Circuit (ASIC), Microcontroller Unit (MCU), Field Programmable Gate Array (FPGA), or integrated circuit used to implement logic operations .
  • the processor may be a single-CPU processor or a multi-CPU processor. It can implement or execute various exemplary logical blocks, modules, and circuits described in conjunction with the disclosure of the embodiments of the present application.
  • the processor may also be a combination of computing functions, for example, a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on.
  • the communication unit 1102 may be a functional module with a transceiver function, and is used to exchange information with the CU, DU or UE.
  • the storage unit 1103 may include one or more memories, and the memories may be devices for storing programs or data in one or more devices or circuits.
  • the storage unit 1103 may exist independently, and is connected to the processing unit 1101 through the communication bus 1104.
  • the storage unit 1103 may also be integrated with the processing unit 1104.
  • the memory may include at least one of the following types: read-only memory (ROM) or other types of static storage devices that can store static information and instructions, random access memory (RAM), or Other types of dynamic storage devices that store information and instructions can also be Electrically Erasable Programmable-only Memory (EEPROM).
  • ROM read-only memory
  • RAM random access memory
  • EEPROM Electrically Erasable Programmable-only Memory
  • the memory can also be a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital universal discs, Blu-ray discs, etc.) , A magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited thereto.
  • the communication bus 1104 may be a Peripheral Component Interconnect (PCI) bus or an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, etc.
  • PCI Peripheral Component Interconnect
  • EISA Extended Industry Standard Architecture
  • the bus can be divided into address bus, data bus, control bus, etc. For ease of presentation, only one thick line is used in FIG. 11 to represent, but it does not mean that there is only one bus or one type of bus.
  • the communication device 1100 may be used in a CU, a DU, a circuit, a hardware component, or a chip.
  • the communication device 1100 may be the CU in the embodiment of the present application.
  • the communication unit 1102 may be a network interface (for example, including an F1 interface between the CU and DU), the processing unit 1101 may be, for example, a processor, and the storage unit 1103 may be, for example, a memory.
  • the CU includes a storage unit 1103, the storage unit 1103 is used to store computer execution instructions, the processing unit 1101 is connected to the storage unit 1103, and the processing unit 1101 executes the computer execution instructions stored in the storage unit 1103 to enable the CU
  • the method executed by the CU in the foregoing embodiment includes the relevant steps executed by the CU in the embodiment shown in FIG. 6 and FIG. 10, and processes executed by other CUs of the technology described in this document. All relevant content of the steps involved in the foregoing method embodiments can be cited in the functional description of the corresponding functional module, which will not be repeated here.
  • the processing unit 1101 is the processor 1201
  • the communication unit 1102 is the network interface 1202
  • the storage unit 1103 is the memory 1203
  • the CU involved in this application may be the CU shown in FIG. 12.
  • the communication device 1100 may be a chip in the CU in the embodiment of the present application.
  • the communication unit 1102 may be an input or output interface, pin or circuit, or the like.
  • the storage unit 1101 may store a computer-executed instruction of the method on the CU side, so that the processing unit 1101 executes the method executed by the CU in the foregoing embodiment, including relevant steps executed by the CU in the embodiment shown in FIG. 6 and FIG. 10 , And other CU implementation of the technology described in this article.
  • the storage unit 1103 can be a register, a cache or RAM, etc.
  • the storage unit 1103 can be integrated with the processing unit 1101; the storage unit 1103 can be a ROM or other types of static storage devices that can store static information and instructions.
  • the storage unit 1103 can be integrated with The processing unit 1101 is independent.
  • the communication device 1100 may be the DU in the embodiment of the present application.
  • the communication unit 1102 may include a network interface (for example, including an F1 interface between the CU and DU), an antenna, and a transceiver.
  • the processing unit 1101 may be a processor, for example, and the storage unit 1103 may be a memory, for example.
  • the DU includes a storage unit 1103, the storage unit 1103 is used to store computer execution instructions, the processing unit 1101 is connected to the storage unit 1103, and the processing unit 1101 executes the computer execution instructions stored in the storage unit 1103 to make the DU
  • the execution method includes the relevant steps executed by the DU in the embodiments shown in FIG. 6 and FIG. 10, and other processes executed by the DU of the technology described in this article. All relevant content of the steps involved in the foregoing method embodiments can be cited in the functional description of the corresponding functional module, which will not be repeated here.
  • the communication unit 1102 When the processing unit 1101 is the processor 1301, the communication unit 1102 includes a network interface 1302a, a transceiver 1302b, and an antenna 1302c, and the storage unit 1103 is a memory 1303, the DU involved in this application may be the DU shown in FIG.
  • the transceiver and the network interface may be integrated on the communication device.
  • the communication unit 1102 integrates the network interface 1302a and the transceiver 1302b.
  • the communication device 1100 may be a chip in the DU in the embodiment of the present application.
  • the communication unit 1102 may be an input or output interface, pin or circuit, or the like.
  • the storage unit 1101 may store a computer-executed instruction of the method on the DU side, so that the processing unit 1101 executes the method executed by the DU in the foregoing embodiment, including related steps executed by the DU in the embodiment shown in FIG. 6 and FIG. 10 , And other processes performed by the DU of the technology described in this article.
  • the storage unit 1103 can be a register, a cache or RAM, etc.
  • the storage unit 1103 can be integrated with the processing unit 1101; the storage unit 1103 can be a ROM or other types of static storage devices that can store static information and instructions.
  • the storage unit 1103 can be integrated with The processing unit 1101 is independent.
  • the embodiment of the present application also provides a computer-readable storage medium.
  • the methods described in the foregoing embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted on a computer-readable medium as one or more instructions or codes.
  • Computer-readable media may include computer storage media and communication media, and may also include any media that can transfer a computer program from one place to another.
  • the storage medium may be any available medium that can be accessed by a computer.
  • the computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used for carrying or with instructions or data structures
  • the required program code is stored in the form of and can be accessed by the computer.
  • any connection is properly termed a computer-readable medium.
  • coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave
  • coaxial cable, fiber optic cable , Twisted pair, DSL or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium.
  • Magnetic disks and optical disks as used herein include compact disks (CDs), laser disks, optical disks, digital versatile disks (DVDs), floppy disks and blu-ray disks, in which disks usually reproduce data magnetically, while optical disks reproduce data optically using lasers. Combinations of the above should also be included in the scope of computer-readable media.
  • the embodiment of the present application also provides a computer program product.
  • the methods described in the foregoing embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. If implemented in software, it can be implemented in whole or in part in the form of computer program products.
  • the computer program product includes one or more computer instructions. When the above computer program instructions are loaded and executed on the computer, the procedures or functions described in the above method embodiments are generated in whole or in part.
  • the above-mentioned computer may be a general-purpose computer, a special-purpose computer, a computer network, network equipment, user equipment, or other programmable devices.

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Abstract

本申请提供一种通信方法及装置，涉及通信技术领域，能够基于CU-DU架构，实现UE-to-Network relay的通信过程。该方法包括：CU生成用户上下文修改请求消息，该用户上下文修改请求消息用于请求DU修改中继用户设备UE的上下文，该用户上下文修改请求消息中携带远程UE的标识、中继UE的承载标识以及与该中继UE的承载标识具有映射关系的逻辑信道的标识，中继UE的承载标识为该中继UE与CU之间的承载的标识，该逻辑信道为远程UE与中继UE之间的逻辑信道；CU向DU发送用户上下文修改请求消息。

Description

一种通信方法及装置
本申请要求在2019年2月2日提交中国专利局、申请号为201910106285.X、发明名称为“一种通信方法及装置”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，尤其涉及一种通信方法及装置。
背景技术
CU-DU架构是指对基站的功能进行拆分，将基站的一部分功能被部署在集中式单元(centralized unit,CU)，另一部分功能被部署在分布式单元(distributed unit,DU)。一种可能的部署方式为按照协议栈将基站拆分为CU和DU。例如，将无线资源控制(Radio Resource Control，RRC)，服务数据适应协议(Service Data Adaptation Protocol，SDAP)以及分组数据汇聚协议(Packet Data Convergence Protocol，PDCP)层部署在CU。其余的无线链路控制(Radio Link Control，RLC)层、介质访问控制(Media Access Control，MAC)层以及物理层(physical,PHY)部署在DU。
那么，当基站采用CU-DU架构进行部署时，如何实现用户设备到网络中继(UE-to-Network relay)的通信过程就成为一个问题。
发明内容
本申请提供一种通信方法及装置，能够基于CU-DU架构，实现UE-to-Network relay的通信过程。
第一方面，本申请提供一种通信方法，包括：CU生成用户上下文修改请求消息，该用户上下文修改请求消息用于请求DU修改中继UE的上下文，该用户上下文修改请求消息中携带远程UE的标识、中继UE的承载标识以及与该中继UE的承载标识具有映射关系的逻辑信道的标识，中继UE的承载标识为该中继UE与CU之间的承载的标识，该逻辑信道为远程UE与中继UE之间的逻辑信道；CU向DU发送用户上下文修改请求消息。
采用该本申请提供的方法，由CU确定中继UE的承载标识与中继UE与远程UE之间的逻辑信道的标识的映射关系，并通过向DU发送用户上下文修改请求消息以请求DU修改中继UE的上下文，以便于后续重新生成中继UE的RRC重配置消息，使得中继UE能够根据该RRC重配置消息完成针对远程UE的RRC消息或者数据包的转发。从而在CU-DU架构下，实现UE-to-Network relay的通信过程。
可选的，用户上下文修改请求消息中还携带与中继UE的承载标识和逻辑信道的标识具有映射关系的远程UE的承载标识，远程UE的承载标识为该远程UE与CU之间的承载的标识。
采用该可选方式，CU在生成用户上下文修改请求消息的过程中，通过中继UE的承载标识、远程UE的承载标识以及该中继UE与该远程UE之间的逻辑信道的标识这三者之间 的映射关系，便于DU在接收到用户上下文修改请求消息后，基于远程UE的承载标识，以及该远程UE与中继UE之间的逻辑信道的标识与该远程UE的承载标识之间的映射关系生成针对远程UE的RRC配置信息。
可选的，该方法还包括：CU向DU发送下行RRC信息传输消息，该下行RRC信息传输消息包括远程UE的下行RRC信息、中继UE在CU-DU接口的标识、第一指示，该下行RRC信息包括远程UE的下行RRC消息以及封装在该下行RRC消息外部的PDCP层和适配信息，适配信息用于指示该下行RRC消息为远程UE的下行RRC消息，第一指示用于指示该下行RRC消息外部封装有适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的下行RRC消息的传输过程。
可选的，该方法还包括：CU接收DU发送的上行RRC信息传输消息，该上行RRC信息传输消息包括远程UE的上行RRC信息、中继UE在CU-DU接口的标识、第一指示，该上行RRC信息包括远程UE的上行RRC消息以及封装在该上行RRC消息外部的PDCP层和适配信息，适配信息用于指示该上行RRC消息为远程UE的上行RRC消息，第一指示用于指示该上行RRC消息外部封装有适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的上行RRC消息的传输过程。
可选的，该方法还包括：CU向DU发送下行通用分组无线服务技术隧道协议GTP-U帧，该下行GTP-U帧包括远程UE的下行数据信息、第一指示、中继UE的GTP-U隧道的隧道端点标识，该下行数据信息包括远程UE的下行数据包以及封装在该下行数据包外部的PDCP层和适配信息，适配信息用于指示该下行数据包为远程UE的下行数据包，第一指示用于指示该下行数据包外部封装有适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的下行数据包的传输过程。
可选的，该方法还包括：CU接收DU发送的上行GTP-U帧，该上行GTP-U帧包括远程UE的上行数据信息、第一指示、中继UE的GTP-U隧道的隧道端点标识，该上行数据信息包括远程UE的上行数据包以及封装在该上行数据包外部的PDCP层和适配信息，适配信息用于指示该上行数据包为远程UE的上行数据包，第一指示用于指示该上行数据包外部封装有适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的上行数据包的传输过程。
可选的，该方法还包括：CU向DU发送用户上下文建立请求消息，该用户上下文建立请求消息包括中继UE的标识、远程UE的标识、远程UE的承载标识与逻辑信道之间的映射关系，该用户上下文建立请求消息用于请求DU建立远程UE的上下文。
基于该可选方式，能够实现当适配层部署在DU的协议栈中时，UE-to-Network relay的通信过程中，建立远程UE的上下文的过程。
可选的，用户上下文修改请求消息还携带第二指示，该第二指示用于指示DU在发送远程UE的下行数据信息或下行RRC信息时，在该下行数据信息或下行RRC信息中增加适配信息，适配信息用于指示该下行数据或下行RRC信息为远程UE的下行数据信息或下行 RRC信息。
可选的，CU生成用户上下文修改请求消息之前，该方法还包括：CU从DU接收由中继UE转发的远程UE的RRC连接建立请求消息、RRC重建立请求消息或者RRC恢复请求消息。
第二方面，本申请提供一种通信方法，该方法包括：DU接收CU发送的用户上下文修改请求消息，该用户上下文修改请求消息中携带远程UE的标识、中继UE的承载标识以及与中继UE的承载标识具有映射关系的逻辑信道的标识，中继UE的承载标识为该中继UE与CU之间的承载的标识，该逻辑信道为远程UE与中继UE之间的逻辑信道；DU根据远程UE的标识、中继UE的承载标识以及逻辑信道的标识，生成中继UE的RRC配置信息，该RRC配置信息包括远程UE的标识、中继UE的承载标识与逻辑信道的标识之间的映射关系。
采用该本申请提供的方法，DU可以基于CU发送的用户上下文修改请求消息，确定中继UE的承载标识与中继UE与远程UE之间的逻辑信道的标识的映射关系，并重新生成中继UE的RRC配置信息，以便于后续CU根据中继UE的RRC配置信息生成中继UE的RRC重配置消息，使得中继UE能够根据该RRC重配置消息完成针对远程UE的RRC消息或者数据包的转发。从而在CU-DU架构下，实现UE-to-Network relay的通信过程。
可选的，用户上下文修改请求消息中还携带与中继UE的承载标识和逻辑信道的标识具有映射关系的远程UE的承载标识，远程UE的承载标识为该远程UE与CU之间的承载的标识；中继UE的承载标识与逻辑信道的标识之间的映射关系，具体为：中继UE的承载标识、逻辑信道的标识以及远程UE的承载标识之间的映射关系。
采用该可选方式，DU可以基于CU发送的用户上下文修改请求消息确定中继UE的承载标识、远程UE的承载标识以及该中继UE与该远程UE之间的逻辑信道的标识这三者之间的映射关系，便于后续基于远程UE的承载标识，以及该远程UE与中继UE之间的逻辑信道的标识与该远程UE的承载标识之间的映射关系生成针对远程UE的RRC配置信息。
可选的，该方法还包括：DU接收CU发送下行RRC信息传输消息，该下行RRC信息传输消息包括远程UE的下行RRC信息、中继UE在CU-DU接口的标识、第一指示，该下行RRC信息包括远程UE的下行RRC消息以及封装在该下行RRC消息外部的PDCP层和适配信息，适配信息用于指示该下行RRC消息为远程UE的下行RRC消息，第一指示用于指示该下行RRC消息外部封装有适配信息；DU向中继UE发送封装了RLC层、MAC层以及PHY层的下行RRC信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该下行RRC消息外部封装有适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的下行RRC消息的传输过程。
可选的，该方法还包括：DU接收中继UE发送的远程UE的上行RRC信息，该上行RRC信息包括远程UE的上行RRC消息，以及封装在该上行RRC消息外部的PDCP层、适配信息、RCL层、MAC层以及PHY层，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该上行RRC消息外部封装有适配信息，适配信息用于指示该上行RRC消息是远程UE的上行RRC消息；DU向CU发送上行RRC信息传输消息，该上行RRC信息传输消息包括中继UE在CU-DU接口的标识、第一指示、该上行RRC消息以及封装在该上行RRC消息外部的PDCP层和适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay 的通信过程中，远程UE的上行RRC消息的传输过程。
可选的，该方法还包括：DU接收CU发送的下行GTP-U帧，该下行GTP-U帧包括远程UE的下行数据信息、第一指示以及中继UE的GTP-U隧道的隧道端点标识，该下行数据信息包括远程UE的下行数据包以及封装在该下行数据包外部的PDCP层和适配信息，适配信息用于指示该下行数据包是远程UE的下行数据包，第一指示用于指示该下行数据包外部封装有适配信息；DU向中继UE发送封装了RLC层、MAC层以及PHY层的该下行数据信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该下行数据包外部封装有适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的下行数据包的传输过程。
可选的，该方法还包括：DU接收中继UE发送的远程UE的上行数据信息，该上行数据信息包括远程UE的上行数据包以及封装在该上行数据包外部的PDCP层、适配信息、RCL层、MAC层以及PHY层，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该上行数据包外部封装有适配信息，适配信息用于指示该上行数据包为远程UE的上行数据包；DU向CU发送上行GTP-U帧，该上行GTP-U帧包括第一指示、中继UE的GTP-U隧道的隧道端点标识、该上行数据包以及封装在该上行数据包外部的PDCP层和适配信息，第一指示用于指示该上行数据包外部封装有适配信息。
基于该可选方式，能够实现当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的上行数据包的传输过程。
可选的，该方法还包括：DU接收CU发送的用户上下文建立请求消息，该用户上下文建立请求消息包括中继UE的标识、远程UE的标识、远程UE的承载标识与逻辑信道之间的映射关系，该用户上下文建立请求消息用于请求DU建立远程UE的上下文；DU根据中继UE的标识、远程UE的标识、远程UE的承载标识与逻辑信道之间的映射关系，生成远程UE的RRC配置信息。
基于该可选方式，能够实现当适配层部署在DU的协议栈中时，UE-to-Network relay的通信过程中，建立远程UE的上下文的过程。
可选的，用户上下文建立请求消息还携带第二指示，该第二指示用于指示DU在向中继UE发送远程UE的下行数据信息或下行RRC信息时，在该下行数据信息或下行RRC信息中增加适配信息，适配信息用于指示该下行数据信息或下行RRC信息是远程UE的下行数据信息或下行RRC信息。
可选的，该方法还包括：DU接收CU发送的下行RRC信息传输消息，该下行RRC信息传输消息包括远程UE的下行RRC信息和远程UE在CU-DU接口的标识，该下行RRC信息包括远程UE的下行RRC消息和封装在该下行RRC消息外部的PDCP层；DU向中继UE发送封装了适配信息、RLC层、MAC层以及PHY层的下行RRC信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该下行RRC消息外部封装有适配信息，适配信息用于指示该下行RRC消息为远程UE的下行RRC消息。
基于该可选方式，能够实现当适配层部署在DU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的下行RRC消息的传输过程。
可选的，该方法还包括：DU接收中继UE发送的上行RRC信息，该上行RRC信息包括 远程UE的上行RRC消息和依次封装在该上行RRC消息外部的PDCP层、适配信息、RLC层、MAC层以及PHY层,RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示该上行RRC消息外部封装有适配信息，适配信息用于指示该上行RRC消息为远程UE的上行RRC消息；DU根据第三指示读取该上行RRC信息中的适配信息，以确定远程UE的承载标识中用于传输该上行RRC信息的承载标识和该远程UE在CU-DU接口的标识；DU向CU发送上行RRC信息传输消息，该上行RRC信息传输消息包括用于传输上行RRC信息的承载标识、远程UE在CU-DU接口的标识、上行RRC消息以及封装在该上行RRC消息外部的PDCP层。
基于该可选方式，能够实现当适配层部署在DU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的上行RRC消息的传输过程。
可选的，该方法还包括：DU接收CU发送的下行GTP-U帧，该下行GTP-U帧包括远程UE的下行数据信息以及远程UE的GTP-U隧道的隧道端点标识，该下行数据信息包括远程UE的下行数据包以及封装在该下行数据包外部的PDCP层；DU向中继UE发送封装了适配信息、RLC层、MAC层以及PHY层的下行数据信息，RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示该下行数据包外部封装有适配信息，适配信息用于指示该下行数据包为远程UE的下行数据包。
基于该可选方式，能够实现当适配层部署在DU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的下行数据包的传输过程。
可选的，该方法还包括：DU接收中继UE发送的上行数据信息，该上行数据信息包括远程UE的上行数据包和依次封装在该上行数据包外部的PDCP层、适配信息、RLC层、MAC层以及PHY层,RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示该上行数据包外部封装有适配信息，适配信息用于指示该上行数据包为远程UE的上行数据包；DU根据第三指示读取该上行数据信息中的适配信息，以确定该远程UE的承载标识中用于传输该上行数据信息的承载标识，和与用于传输该上行数据信息的承载标识对应的远程UE的GTP-U隧道的隧道端点标识；DU向CU发送上行GTP-U帧，该上行GTP-U帧包括用于传输该上行数据信息的承载标识、远程UE的GTP-U隧道的隧道端点标识、该上行数据包以及封装在该上行数据包外部的PDCP层。
基于该可选方式，能够实现当适配层部署在DU的协议栈中时，UE-to-Network relay的通信过程中，远程UE的上行数据包的传输过程。
第三方面，本申请实施例提供了一种通信装置，该通信装置可以是CU或者是CU内的芯片。该通信装置具有实现上述第一方面所述的方法的功能。该功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块。该装置包括处理单元和通信单元，可选的，该装置还可以包括存储单元。该处理单元可以通过该通信单元完成信息的接收或者发送，该处理单元可以对信息进行处理，使得该通信装置实现上述第一方面所述的方法。
示例性的，处理单元，用于生成用户上下文修改请求消息，该用户上下文修改请求消息用于请求DU修改中继用户设备UE的上下文，该用户上下文修改请求消息中携带远程UE的标识、中继UE的承载标识以及与该中继UE的承载标识具有映射关系的逻辑信道的标识，中继UE的承载标识为该中继UE与CU之间的承载的标识，该逻辑信道为远程UE与中继UE之间的逻辑信道；处理单元，还用于通过通信单元向DU发送用户上下文修改请求消息。
可选的，用户上下文修改请求消息中还携带与中继UE的承载标识和逻辑信道的标识具有映射关系的远程UE的承载标识，远程UE的承载标识为该远程UE与CU之间的承载的标识。
可选的，处理单元，还用于通过通信单元向DU发送下行RRC信息传输消息，该下行RRC信息传输消息包括远程UE的下行RRC信息、中继UE在CU-DU接口的标识、第一指示，该下行RRC信息包括远程UE的下行RRC消息以及封装在该下行RRC消息外部的PDCP层和适配信息，适配信息用于指示该下行RRC消息为远程UE的下行RRC消息，第一指示用于指示该下行RRC消息外部封装有适配信息。
可选的，处理单元，还用于通过通信单元接收DU发送的上行RRC信息传输消息，该上行RRC信息传输消息包括远程UE的上行RRC信息、中继UE在CU-DU接口的标识、第一指示，该上行RRC信息包括远程UE的上行RRC消息以及封装在该上行RRC消息外部的PDCP层和适配信息，适配信息用于指示该上行RRC消息为远程UE的上行RRC消息，第一指示用于指示该上行RRC消息外部封装有适配信息。
可选的，处理单元，还用于通过通信单元向DU发送下行GTP-U帧，该下行GTP-U帧包括远程UE的下行数据信息、第一指示、中继UE的GTP-U隧道的隧道端点标识，该下行数据信息包括远程UE的下行数据包以及封装在该下行数据包外部的PDCP层和适配信息，适配信息用于指示该下行数据包为远程UE的下行数据包，第一指示用于指示该下行数据包外部封装有适配信息。
可选的，处理单元，还用于通过通信单元接收DU发送的上行GTP-U帧，该上行GTP-U帧包括远程UE的上行数据信息、第一指示、中继UE的GTP-U隧道的隧道端点标识，该上行数据信息包括远程UE的上行数据包以及封装在该上行数据包外部的PDCP层和适配信息，适配信息用于指示该上行数据包为远程UE的上行数据包，第一指示用于指示该上行数据包外部封装有适配信息。
可选的，处理单元，还用于通过通信单元向DU发送用户上下文建立请求消息，该用户上下文建立请求消息包括中继UE的标识、远程UE的标识、远程UE的承载标识与逻辑信道之间的映射关系，该用户上下文建立请求消息用于请求DU建立远程UE的上下文。
可选的，用户上下文修改请求消息还携带第二指示，该第二指示用于指示DU在发送远程UE的下行数据信息或下行RRC信息时，在该下行数据信息或下行RRC信息中增加适配信息，适配信息用于指示该下行数据或下行RRC信息为远程UE的下行数据信息或下行RRC信息。
可选的，处理单元生成用户上下文修改请求消息之前，还用于通过通信单元DU接收由中继UE转发的远程UE的RRC连接建立请求消息、RRC重建立请求消息或者RRC恢复请求消息。
作为一种可选的设计，当该通信装置为CU时，该处理单元例如可以是处理器，该通信单元例如可以包括网络接口。可选地，该CU还包括存储单元，该存储单元例如可以是存储器。当该通信装置包括存储单元时，该存储单元用于存储计算机执行指令，该处理单元与该存储单元连接，该处理单元执行该存储单元存储的计算机执行指令，以使该CU执行上述第一方面所述的方法。
在另一种可能的设计中，当该通信装置为CU内的芯片时，该处理单元例如可以是处 理器，该通信单元例如可以是输入/输出接口、管脚或电路等。该处理单元可执行存储单元存储的计算机执行指令，以使芯片执行上述第一方面或第一方面的任意一项的所述的通信方法。可选地，该存储单元为该芯片内的存储单元，如寄存器、缓存等，该存储单元还可以是该CU内的位于该芯片外部的存储单元，如只读存储器(read-only memory，ROM)或可存储静态信息和指令的其他类型的静态存储设备，随机存取存储器(random access memory，RAM)等。
本申请提供的通信装置的技术效果可以参见上述第二方面或第二方面的各个实现方式的技术效果，此处不再赘述。
第四方面，本申请实施例提供了一种通信装置，该通信装置可以是DU或者是DU内的芯片。该通信装置具有实现上述第一方面所述的方法的功能。该功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。该硬件或软件包括一个或多个与上述功能相对应的模块。该装置包括处理单元和通信单元，可选的，该装置还可以包括存储单元。该处理单元可以通过该通信单元完成信息的接收或者发送，该处理单元可以对信息进行处理，使得该通信装置实现上述第二方面所述的方法。
示例性的，处理单元，用于通过通信单元接收CU发送的用户上下文修改请求消息，该用户上下文修改请求消息中携带远程UE的标识、中继UE的承载标识以及与中继UE的承载标识具有映射关系的逻辑信道的标识，中继UE的承载标识为该中继UE与CU之间的承载的标识，该逻辑信道为远程UE与中继UE之间的逻辑信道；处理单元，还用于根据远程UE的标识、中继UE的承载标识以及逻辑信道的标识，生成中继UE的RRC配置信息，该RRC配置信息包括远程UE的标识、中继UE的承载标识与逻辑信道的标识之间的映射关系。
可选的，用户上下文修改请求消息中还携带与中继UE的承载标识和逻辑信道的标识具有映射关系的远程UE的承载标识，远程UE的承载标识为该远程UE与CU之间的承载的标识；中继UE的承载标识与逻辑信道的标识之间的映射关系，具体为：中继UE的承载标识、逻辑信道的标识以及远程UE的承载标识之间的映射关系。
可选的，处理单元，还用于通过通信单元接收CU发送下行RRC信息传输消息，该下行RRC信息传输消息包括远程UE的下行RRC信息、中继UE在CU-DU接口的标识、第一指示，该下行RRC信息包括远程UE的下行RRC消息以及封装在该下行RRC消息外部的PDCP层和适配信息，适配信息用于指示该下行RRC消息为远程UE的下行RRC消息，第一指示用于指示该下行RRC消息外部封装有适配信息；处理单元，还用于通过通信单元向中继UE发送封装了RLC层、MAC层以及PHY层的下行RRC信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该下行RRC消息外部封装有适配信息。
可选的，处理单元，还用于通过通信单元接收中继UE发送的远程UE的上行RRC信息，该上行RRC信息包括远程UE的上行RRC消息，以及封装在该上行RRC消息外部的PDCP层、适配信息、RCL层、MAC层以及PHY层，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该上行RRC消息外部封装有适配信息，适配信息用于指示该上行RRC消息是远程UE的上行RRC消息；处理单元，还用于通过通信单元向CU发送上行RRC信息传输消息，该上行RRC信息传输消息包括中继UE在CU-DU接口的标识、第一指示、该上行RRC消息以及封装在该上行RRC消息外部的PDCP层和适配信息。
可选的，处理单元，还用于通过通信单元接收CU发送的下行GTP-U帧，该下行GTP-U帧包括远程UE的下行数据信息、第一指示以及中继UE的GTP-U隧道的隧道端点标识，该下行数据信息包括远程UE的下行数据包以及封装在该下行数据包外部的PDCP层和适配信息，适配信息用于指示该下行数据包是远程UE的下行数据包，第一指示用于指示该下行数据包外部封装有适配信息；处理单元，还用于通过通信单元向中继UE发送封装了RLC层、MAC层以及PHY层的该下行数据信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该下行数据包外部封装有适配信息。
可选的，处理单元，还用于通过通信单元接收中继UE发送的远程UE的上行数据信息，该上行数据信息包括远程UE的上行数据包以及封装在该上行数据包外部的PDCP层、适配信息、RCL层、MAC层以及PHY层，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该上行数据包外部封装有适配信息，适配信息用于指示该上行数据包为远程UE的上行数据包；处理单元，还用于通过通信单元向CU发送上行GTP-U帧，该上行GTP-U帧包括第一指示、中继UE的GTP-U隧道的隧道端点标识、该上行数据包以及封装在该上行数据包外部的PDCP层和适配信息，第一指示用于指示该上行数据包外部封装有适配信息。
可选的，处理单元，还用于通过通信单元接收CU发送的用户上下文建立请求消息，该用户上下文建立请求消息包括中继UE的标识、远程UE的标识、远程UE的承载标识与逻辑信道之间的映射关系，该用户上下文建立请求消息用于请求DU建立远程UE的上下文；处理单元，还用于通过通信单元根据中继UE的标识、远程UE的标识、远程UE的承载标识与逻辑信道之间的映射关系，生成远程UE的RRC配置信息。
可选的，用户上下文建立请求消息还携带第二指示，该第二指示用于指示DU在向中继UE发送远程UE的下行数据信息或下行RRC信息时，在该下行数据信息或下行RRC信息中增加适配信息，适配信息用于指示该下行数据信息或下行RRC信息是远程UE的下行数据信息或下行RRC信息。
可选的，处理单元，还用于通过通信单元接收CU发送的下行RRC信息传输消息，该下行RRC信息传输消息包括远程UE的下行RRC信息和远程UE在CU-DU接口的标识，该下行RRC信息包括远程UE的下行RRC消息和封装在该下行RRC消息外部的PDCP层；处理单元，还用于通过通信单元向中继UE发送封装了适配信息、RLC层、MAC层以及PHY层的下行RRC信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示该下行RRC消息外部封装有适配信息，适配信息用于指示该下行RRC消息为远程UE的下行RRC消息。可选的，处理单元，还用于通过通信单元接收中继UE发送的上行RRC信息，该上行RRC信息包括远程UE的上行RRC消息和依次封装在该上行RRC消息外部的PDCP层、适配信息、RLC层、MAC层以及PHY层,RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示该上行RRC消息外部封装有适配信息，适配信息用于指示该上行RRC消息为远程UE的上行RRC消息；处理单元，还用于根据第三指示读取该上行RRC信息中的适配信息，以确定远程UE的承载标识中用于传输该上行RRC信息的承载标识和该远程UE在CU-DU接口的标识；处理单元，还用于通过通信单元向CU发送上行RRC信息传输消息，该上行RRC信息传输消息包括用于传输上行RRC信息的承载标识、远程UE在CU-DU接口的标识、上行RRC消息以及封装在该上行RRC消息外部的PDCP层。
可选的，处理单元，还用于通过通信单元接收CU发送的下行GTP-U帧，该下行GTP-U帧包括远程UE的下行数据信息以及远程UE的GTP-U隧道的隧道端点标识，该下行数据信息包括远程UE的下行数据包以及封装在该下行数据包外部的PDCP层；处理单元，还用于通过通信单元向中继UE发送封装了适配信息、RLC层、MAC层以及PHY层的下行数据信息，RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示该下行数据包外部封装有适配信息，适配信息用于指示该下行数据包为远程UE的下行数据包。
可选的，处理单元，还用于通过通信单元接收中继UE发送的上行数据信息，该上行数据信息包括远程UE的上行数据包和依次封装在该上行数据包外部的PDCP层、适配信息、RLC层、MAC层以及PHY层,RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示该上行数据包外部封装有适配信息，适配信息用于指示该上行数据包为远程UE的上行数据包；处理单元，还用于根据第三指示读取该上行数据信息中的适配信息，以确定该远程UE的承载标识中用于传输该上行数据信息的承载标识，和与用于传输该上行数据信息的承载标识对应的远程UE的GTP-U隧道的隧道端点标识；处理单元，还用于通过通信单元向CU发送上行GTP-U帧，该上行GTP-U帧包括用于传输该上行数据信息的承载标识、远程UE的GTP-U隧道的隧道端点标识、该上行数据包以及封装在该上行数据包外部的PDCP层。
作为一种可选的设计，当该通信装置为DU时，该处理单元例如可以是处理器，该通信单元例如可以包括天线、收发机和网络接口。可选地，该通信装置还包括存储单元，该存储单元例如可以是存储器。当该通信装置包括存储单元时，该存储单元用于存储计算机执行指令，该处理单元与该存储单元连接，该处理单元执行该存储单元存储的计算机执行指令，以使该DU执行上述第二方面所述的方法。
在另一种可能的设计中，当该通信装置为DU内的芯片时，该处理单元例如可以是处理器，该通信单元例如可以是输入/输出接口、管脚或电路等。该处理单元可执行存储单元存储的计算机执行指令，以使芯片执行上述第二方面或第二方面的任意一项的所述的通信方法。可选地，该存储单元为该芯片内的存储单元，如寄存器、缓存等，该存储单元还可以是该DU内的位于该芯片外部的存储单元，如ROM或可存储静态信息和指令的其他类型的静态存储设备，随机存取存储器RAM等。
本申请提供的装置的技术效果可以参见上述第二方面或第二方面的各个实现方式的技术效果，此处不再赘述。
示例性的，上述任一处提到的处理器，可以是一个通用中央处理器(Central Processing Unit，CPU)，微处理器，特定应用集成电路(application-specific integrated circuit，ASIC)，或一个或多个用于控制上述第二方面的方法的程序执行的集成电路。
本申请提供的通信装置的技术效果可以参见上述第二方面或第二方面的各个实现方式的技术效果，此处不再赘述。
第五方面，本申请实施例提供了一种计算机存储介质，存储有用于实现上述第一方面所述的方法的程序。当所述程序在装置中运行时，使得该装置执行上述第一方面的方法。
第六方面，本申请实施例提供了一种计算机存储介质，存储有用于实现上述第二方面所述的方法的程序。当所述程序在装置中运行时，使得该装置执行上述第二方面的方法。
第七方面，本申请实施例提供了一种计算机程序产品，该程序产品包括程序，当该程 序被运行时，使得上述第一方面所述的方法被执行。
第八方面，本申请实施例提供了一种计算机程序产品，该程序产品包括程序，当该程序被运行时，使得上述第二方面所述的方法被执行。
第九方面，本申请提供一种通信系统，包括如第三方面所述的通信装置和如第四方面所述的通信装置。
附图说明
图1为本申请提供的一种UE-to-Network relay的通信系统示意图；
图2为本申请提供的一种基于CU-DU架构部署的基站的结构示意图；
图3为本申请提供的一种可能的用户面协议栈的示意图；
图4为本申请提供的一种可能的控制面协议栈的示意图；
图5为本申请提供的一种UE-to-Network relay的通信原理示意图；
图6为本申请提供的一种通信方法的一个实施例的流程图；
图7为本申请提供的另一种可能的用户面协议栈的示意图；
图8为本申请提供的另一种可能的控制面协议栈的示意图；
图9为本申请提供的另一种UE-to-Network relay的通信原理示意图；
图10为本申请提供的另一种通信方法的一个实施例的流程图；
图11为本申请提供的一种通信装置的结构示意图；
图12为本申请提供的一种CU的结构示意图；
图13为本申请提供的一种DU的结构示意图。
具体实施方式
首先，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；本申请中的“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。另外，在本申请的描述中，“多个”是指两个或两个以上。
其次，本申请提供的通信方法用于在CU-DU架构下，实现UE-to-Network relay通信。为了便于读者理解本申请提供的通信方法，下面结合附图对基于L2中继的UE-to-Network relay通信系统和采用CU-DU架构的基站进行示例性的介绍。
如图1所示，为本申请提供的一种UE-to-Network relay的通信系统，包括基站和多个用户设备(ueser equipment，UE)。在该多个UE中，一部分UE可以作为中继，为另一部分UE提供中继服务。为了便于描述，下文中将能够提供中继服务的UE称为中继UE，将通过中继UE与基站进行信息交互的UE称为远程(remote)UE。在UE-to-Network relay的通信系统中，远程UE将自己的数据和RRC消息发送给中继UE，中继UE通过中继UE与基站之间的承载，将远程UE的数据和RRC消息转发给基站。示例性的，该承载可以是中继UE与基站之间的数据无线承载(data radio bearer，DRB)和信令无线承载(signal radio bearer，DRB)。一般情况下，中继UE通过自己的DRB向基站转发远程UE的数据，通过自己的SRB向基站转发远程UE的RRC消息。也不排除中继UE通过自己的DRB向基站转发远程UE的RRC消息，通过自己的SRB向基站转发远程UE的数据的情况。
图1中的基站可以是基于CU-DU架构部署的基站，即将LTE系统中传统基站的功能分别部署在CU和DU这两个单元中。例如，LTE系统中传统基站的RLC层、MAC层以及PHY层功能部署在DU中，剩余的功能(例如，RRC层、PDCP层功能)部署在CU。此外，CU中还部署有LTE系统中核心网的非接入层(non-access stratum，NAS)的功能。可选的，在第五代移动通信(the 5th Generation mobile communication technology，5G)系统中，CU中PDCP层之上还可以部署有SDAP层的功能。
如图2所示，基于CU-DU架构部署的基站可以由一个CU和多个DU构成，多个DU可以共用一个CU，从而降低成本，且边缘网络扩展。在5G系统中，CU与DU之间通过F1接口连接，在LTE系统中，CU与DU之间通过V1/W1接口连接。在5G系统中，CU与CU之间通过Xn接口连接，以代表所属基站通过Xn接口实现基站间的信息交互。在5G系统中，CU与5G核心网(5GC)通过NG接口连接，以代表所属基站通过NG接口与核心网设备进行信息交互。其中，5GC可以包括5G系统中的接入和移动管理功能(access and mobility management function，AMF)和/或用户面管理功能(user plane function，UPF)。
本申请所涉及到的UE(例如，本申请中所提及的中继UE和远程UE)可以是具有无线通信功能的手持设备、车载设备、可穿戴设备、计算设备或连接到无线调制解调器的其它处理设备,以及各种形式的UE、移动台(mobile station,MS)，终端(terminal)，终端设备(terminal equipment)等等。为方便描述，本申请中，简称为用户设备或UE。
在UE-to-Network relay通信中，由于中继UE是通过自己的承载，向基站传输远程UE的数据包和RRC消息。因此，中继UE与基站之间的协议栈中一般会设置适配层，用于设置供中继UE或基站获知远程UE、远程UE的承载和/或远程UE与中继UE之间的逻辑信道的适配信息。例如对于上行而言，中继UE可以根据基站的RRC配置信息获知接收到的远程UE的数据包/RRC消息需要通过该中继UE的哪个DRB/SRB传输给基站，接着在远程UE的数据包/RRC消息外部封装适配层的适配信息，以便于基站获知所述数据包/RRC消息是哪个远程UE的哪个承载，或者是哪个UE以及通过哪个远程UE与中继UE之间的逻辑信道传输的。对于下行而言，基站在数据包/RRC消息外部封装的适配信息，中继UE通过DRB/SRB从基站接收到该数据包/RRC消息后，通过基站在该数据包/RRC消息外部封装的适配信息获知需要转发给哪个远程UE，以及发送给远程UE的哪个承载，或者通过中继UE和远程UE之间的哪个逻辑信道发送给远程UE。
在CU-DU架构中，适配层可以部署在CU的协议栈中，也可以部署在DU的协议栈中。下面分别以在CU的协议栈中部署适配层，和在DU的协议栈中部署适配层这两种部署方式，对本申请提供的通信方法进行示例性的说明。
针对在CU的协议栈中部署适配层的方式，UE-to-Network relay的通信系统中远程UE、中继UE、CU和DU之间的一种可能的用户面协议栈可以如图3所示。远程UE与中继UE之间通过PC5接口交互信息，与CU之间建立端到端的PDCP层进行交互。中继UE与DU之间通过Uu接口交互信息。而远程UE的PDCP包通过中继UE和DU透传至CU，而RLC包、MAC包以及PHY包需要经过中继UE以及DU的处理。因此，如图3所示，远程UE的用户面协议栈包括PDCP层、在PC5接口的RLC层、MAC层、PHY层；中 继UE在PC5接口的用户面协议栈中包括RLC层、MAC层、PHY层，在与DU之间Uu接口的用户面协议栈包括RLC层、MAC层、PHY层。此外，中继UE的用户面协议栈还包括适配层，该适配层的适配信息通过DU透传至CU。DU在与中继UE之间Uu接口的用户面协议栈包括RLC层、MAC层、PHY层。DU与CU之间的用户面协议栈包括层1/层2(layer 1/layer 1，L1/L2)层、用户数据报协议/互联网协议(User Datagram Protocol/Internet Protocol，UDP/IP)层、通用分组无线服务技术隧道协议(General Packet Radio Service Tunneling Protocol User Plane，GTP-U)层。CU中的用户面协议栈包括与DU之间的L1/L2层、UDP/IP层、GTP-U层，与中继UE之间的适配层，与远程UE之间在Uu接口的PDCP层。
与图3相对应的，UE-to-Network relay的通信系统中远程UE、中继UE、CU和DU之间的一种可能的控制面协议栈可以如图4所示。远程UE的控制面协议栈包括与CU之间的RRC层和PDCP层，以及与中继UE之间在PC5接口的RLC层、MAC层和PHY层。中继UE的控制面协议栈包括与远程UE之间在PC5接口的RLC层、MAC层和PHY层，与DU之间在Uu接口的RLC层、MAC层和PHY层，与CU之间的适配层。DU的控制面协议栈包括与中继UE之间在Uu接口的RLC层、MAC层和PHY层，与CU之间的L1/L2层、流控制传输协议/互联网协议(Stream Control Transmission Protocol/Internet Protocol，SCTP/IP)层、F1应用程序协议(F1 Application Protocol，F1AP)层。CU的控制面协议栈包括与DU之间的L1/L2层、SCTP/IP层和F1AP层，与中继UE之间的适配层，与远程UE之间在Uu接口的PDCP层和RRC层。
关于适配层在中继UE和CU的协议栈中的设置方案，示例性的，本申请提供两种方案，包括如下所述方案一和方案二。
方案一是当传输中继UE的数据包/RRC消息时，CU和中继UE的协议栈中不包括适配层，而当传输远程UE的数据包/RRC消息时，CU和中继UE的协议栈中才会包括适配层。即对于上行而言，中继UE在发送上行数据包/上行RRC消息时，若发送的是中继UE自己的上行数据包/上行RRC消息，中继UE则不需要为该上行数据包/上行RRC消息封装适配信息。若发送的是远程UE的上行数据包/上行RRC消息，中继UE则需为该上行数据包/上行RRC消息封装适配信息，以向CU指示该上行数据包/上行RRC消息是远程UE的。同理，对于下行而言，CU在发送在发送下行数据包/下行RRC消息时，若发送的是中继UE下行数据包/下行RRC消息，CU则不需要为该下行数据包/下行RRC消息封装适配信息。若发送的是远程UE的下行数据包/下行RRC消息，CU则需要为该下行数据包/下行RRC消息封装适配信息，以向中继UE指示该下行数据包/下行RRC消息是远程UE的。由于适配层可能存在或不存在，所以中继或基站有必要在发送每个数据包/RRC消息时指示对方适配层是否存在。
方案二是CU和中继UE的协议栈中始终包括适配层。对于上行而言，中继UE无论是发送自己的数据包/RRC消息，还是转发远程UE的数据包/RRC消息，中继UE都会为发送的数据包/RRC消息封装适配信息，供CU获知中继UE发送的数据包/RRC消息是远程UE的还是中继UE自己。对于下行而言，CU无论通过中继UE向远程UE发送数据包/RRC消息，还是直接给中继UE发送数据包/RRC消息，CU都会为发送的数据包/RRC消息封装配置信息，供中继UE获知CU下发的数据包/RRC消息发给中继UE的还是发 给远程UE。对于方案二，由于适配层一直存在，则中继或基站在发送每个数据包/RRC消息时不需要指示对方适配层是否存在。
那么，基于如图3和图4所示的协议栈，在CU-DU架构中，由于适配层部署在CU的协议栈中，DU不需要判断接收到中继UE发送的数据包/RRC消息是中继UE的，还是哪个远程UE。对于用户面数据包，DU可以直接由中继UE发送该数据包的DRB所对应的GTP-U隧道，将该数据包传输给CU。对于控制面的RRC消息，DU直接通过该中继UE相关的CU-DU之间的接口(例如，5G系统中的F1接口)的控制面消息，将该RRC消息发送给CU。如图5所示，若该数据包/RRC消息是中继UE的，CU则将该数据包/RRC消息发送给中继UE对应的PDCP实体(通信路线参见图5所示粗实线，PDCP1为中继UE对应的PDCP实体)。若该数据包/RRC消息是远程UE的，CU则从中继UE的GTP-U隧道或者F1接口接收到该数据包/RRC消息后，基于适配层的适配信息的指示，确定该数据包/RRC消息是哪个远程UE的哪个承载。例如，CU基于适配信息确定数据包/RRC消息是远程UE1的，CU则将该数据包/RRC消息发送给对应的PDCP实体(通信路线参见图5所示虚线，PDCP2为中继UE对应的PDCP实体)。
基于上述通信原理可知，在适配层部署在CU的协议栈中的场景下，当一个远程UE通过中继UE向CU-DU架构的基站请求建立RRC连接，或者请求恢复RRC连接，或者请求重建立RRC连接时，CU和DU可以无需为该远程UE建立上下文，但需要修改中继UE的上下文，以使得中继UE可以为该远程UE提供中继服务。
示例性的，参见图6，为本申请提供的一种通信方法的一个实施例的流程图，主要描述适配层部署在CU侧时，远程UE通过中继UE向基站请求建立RRC连接、恢复RRC连接，或者请求重建立RRC连接的过程。该方法包括：
步骤601，CU生成用户上下文修改请求(UE context modification request)消息，该用户上下文修改请求消息用于请求DU修改中继UE的上下文，该用户上下文修改请求消息中携带远程UE的标识、该中继UE的承载标识以及与该中继UE的承载标识具有映射关系的逻辑信道的标识，该中继UE的承载标识为该中继UE与CU之间的承载的标识，该逻辑信道为该远程UE与该中继UE之间的逻辑信道。
示例性的，该远程UE和该中继UE之间的逻辑信道为该远程UE和该中继UE之间的侧链路的逻辑信道，或该远程UE和该中继UE之间的PC5接口(也可以称为sidelink接口)的逻辑信道，远程UE和中继UE通过逻辑信道采用直接传输的方式进行信息交互。
在本申请中，CU在接收到远程UE的请求消息(例如，RRC连接请求消息，RRC重建立请求消息或者RRC恢复请求消息)后，即可生成用户上下文修改请求消息，用以请求DU修改为该远程UE提供中继服务的中继UE的上下文。
示例性的，远程UE的标识可以是CU接收到远程UE的请求消息中携带的远程UE的标识。例如，该远程UE的标识可以是远程UE的层2标识(layer 2 identification，L2ID)，也可以是远程UE在该远程UE与中继UE之间的PC5接口的标识，或者是远程UE的L2ID和PC5接口的标识的组合。远程UE的标识可以是远程UE自己携带在请求消息中的，也可以是中继UE在转发请求消息时携带在适配信息中的。CU通过接收到的远程UE的标识，确定是远程UE的请求，且由转发该请求消息的中继UE作为中继， 为该远程UE提供中继服务。因此，CU需要为该远程UE分配中继UE的承载，确定由该中继UE的哪个承载转发该远程UE的数据包/RRC消息，即CU需确定该中继UE的承载标识与逻辑信道的标识之间的映射关系。示例性的，CU可以请求为中继UE增加DRB和SRB。然后确定该新增的DRB的标识和SRB的标识与该中继UE和远程UE之间的逻辑信道的标识对之间的映射关系。
或者，CU也可以修改已经为该中继UE分配的DRB和SRB的标识所对应的逻辑信道的标识集合，即将远程UE的标识，以及该中继UE和远程UE之间的逻辑信道的标识添加到为该中继UE分配的DRB和SRB的标识所对应的逻辑信道标识集合中。
需要说明的是，当该中继UE与远程UE之间存在多个逻辑信道时，CU可以为每个逻辑信道分配不同的中继UE的SRB或者DRB。也可以为该多个逻辑信道分配相同的中继UE的SRB或者DRB。即中继UE的一个承载可以对应一个或多个与不同远程UE之间的逻辑信道。
示例性的，以远程UE2为例，假设在远程UE2通过中继UE向CU和DU请求RRC连接，远程UE1已经通过中继UE完成了RRC连接。中继UE当前的承载使用情况为：中继UE的SRB1和DRB1用于传输中继UE自己的RRC消息和数据包，中继UE的SRB2与远程UE1与中继UE之间的逻辑信道LCID1具有映射关系(即由中继UE的SRB2传输远程UE1的上下行RRC消息)，中继UE的DRB2与远程UE1与中继UE之间的逻辑信道LCID2具有映射关系(即由中继UE的DRB2传输远程UE1的上下行数据包)。
当CU接收到由该中继UE转发的远程UE2的RRC连接请求消息时，CU可以确定远程UE和中继UE之间的PC5接口的逻辑信道LCID3和LCID4为用于传输SRB1和SRB2的RRC消息的逻辑信道，逻辑信道LCID5和逻辑信道LCID6为用于传输远程UE的DRB1和DRB2的数据包的逻辑信道。然后CU分别为LCID3和LCID4分配中继UE的SRB，为LCID5和LCID6分配中继UE的DRB。例如，CU建立中继UE的SRB2的标识和LCID3、LCID4之间的映射关系，以确定由中继UE的SRB2传输逻辑信道LCID3和LCID4上传输的远程UE2的SRB1和SRB2对应的上下行RRC消息。那么，CU可以将LCID3、LCID4添加到中继UE的SRB2的标识所对应的逻辑信道的标识的集合中，修改之后中继UE的SRB2的标识对应远程UE1的标识和LCID1，以及远程UE2的标识和LCID3、LCID4。
CU请求增加中继的DRB，并建立该增加的DRB与LCID5、LCID6之间的映射关系。例如，请求增加DRB3，并建立该中继UE的DRB3的标识与LCID5、LCID6之间的映射关系，以确定由中继UE的DRB3传输LCID5和LCID6上传输的远程UE2的DRB1和DRB2的上下行数据包。
当CU确定中继UE的承载标识与逻辑信道的标识之间的映射关系后，即可将远程UE的标识、修改或者增加的中继UE的承载标识，以及与修改或者增加的中继UE的承载标识具有映射关系的逻辑信道的标识携带在用户上下文修改请求消息中，发送至DU。以请求DU修改中继UE的RRC配置以及上下文。
例如，该用户上下文修改请求消息携带远程UE2的标识、中继UE的SRB2的标识、与该中继UE的SRB2的标识对应的LCID3和LCID4、中继UE的DRB3的标识、与该中继UE的DRB3的标识对应的LCID5和LCID6。CU通过该用户上下文修改请求消息请求DU修改中继UE的上下文，并生成针对中继UE的RRC配置信息，以使得中继的UE的 RRC配置信息中具有远程UE2的标识、中继UE的SRB2的标识与LCID3和LCID4之间的映射关系、中继UE的DRB3的标识与LCID5和LCID6之间的映射关系。
需要说明的是，若CU请求中继UE增加DRB，例如，CU请求增加中继UE的DRB3，CU则可以在用户上下文修改请求消息中携带该中继UE的DRB3的GTP-U隧道在CU侧的隧道端点标识(tunnel endpoint identity，TEID)，以请求DU反馈该中继UE的DRB3的GTP-U隧道在DU侧的TEID。
在一个示例中，由于DU在生成针对远程UE的RRC配置信息时，需要在该远程UE的RRC配置信息中包含该远程UE的承载标识，以及该远程UE与中继UE之间的逻辑信道的标识与该远程UE的承载标识之间的映射关系。因此，CU还可以将与中继UE的承载标识和该逻辑信道的标识具有映射关系的远程UE的承载标识携带在该用户上下文修改请求消息发送给DU，以便DU生成针对远程UE的RRC配置信息。示例性的，远程UE的承载标识为远程UE与CU之间的承载的标识。也就是说，CU在生成用户上下文修改请求消息的过程中，CU可以建立中继UE的承载标识、远程UE的承载标识以及该中继UE与该远程UE之间的逻辑信道的标识这三者之间的映射关系。远程UE的承载和该中继UE与该远程UE之间的逻辑信道是一一对应的。例如，远程UE2的DRB1与LCID5对应，远程UE2的DRB2与LCID6对应，远程UE2的SRB1与LCID3对应，远程UE2的SRB2与LCID4对应。当CU建立三者之间的映射关系后，中继UE的DRB3为远程UE2的DRB1和DRB2上传输的数据包提供转发服务，中继UE2的SRB2为远程UE2的SRB1和SRB2上传输的RRC消息提供转发服务。
该用户上下文修改请求消息可以封装在CU-DU接口消息中发送给DU。示例性的，在5G系统中，该用户上下文修改请求消息可以封装在F1消息中，CU通过与DU之间的F1接口发送至DU。示例性的，封装该用户上下文修改请求消息的F1消息中可以携带中继UE在CU-DU接口的标识，包括CU给中继UE分配的F1接口的CU侧标识和DU给中继UE分配的F1接口的DU侧标识。DU和CU可以通过中继UE在F1接口的标识，识别该用户上下文修改请求消息。
此外，该用户上下文修改请求消息中还携带有修改或增加的DRB的服务质量(Quality of Service，QoS)信息，以及修改或增加的DRB所对应的逻辑信道的QoS信息，以便于DU为远程UE配置PC5接口的资源池。
步骤602，CU向DU发送用户上下文修改请求消息。
步骤603，DU根据远程UE的标识、中继UE的承载标识以及逻辑信道的标识，生成该中继UE的RRC配置信息，该RRC配置信息包括远程UE的标识、中继UE的承载标识与逻辑信道的标识之间的映射关系。
DU接收到用户上下文修改请求消息后，确认需要修改中继UE的上下文，并根据该用户上下文修改请求消息中携带的信息生成该中继UE的RRC配置信息。以使得中继UE的RRC配置信息中包括远程UE的标识，以及中继UE的承载标识与该中继UE与该远程UE之间的逻辑信道的标识之间的映射关系。或者，当上述步骤601中，CU在用户上下文修改请求消息中还携带有远程UE的承载标识，那么DU生成的针对中继UE的RRC配置信息中可以包括远程UE的标识，以及中继UE的承载标识、远程UE的承载标识、该中继UE与该远程UE之间的逻辑信道的标识这三者之间的映射关系。示例性 的，RRC配置信息具体可以为小区组配置(Cell Group Config)信息。
示例性的，以远程UE2为例，DU生成的该中继UE的RRC配置信息中，中继UE的承载标识、远程UE2的承载标识、以及中继UE与远程UE2之间的逻辑信道的标识这三者之间的映射关系可以如下表1所示：
表1
Figure PCTCN2020070097-appb-000001
可以理解的是，中继UE的DRB3为CU请求增加的DRB，那么DU在生成中继UE的配置信息时，还需要为该增加的中继UE的DRB3分配对应的GTP-U隧道的DU侧的TEID。并将该DU侧的TEID携带在用户上下文修改响应(UE context modification response)消息中反馈给CU，完成与该中继UE的DRB3对应的GTP-U隧道的建立。
此外，该中继UE的RRC配置信息中还可以包括DU配置的远程UE与中继UE之间的PC5接口的资源池信息。示例性的，资源池的配置可以包含侧链路间断传输配置(sl-DiscConfig)、侧链路公共配置(sl-CommonConfig)、侧链路车联网专用配置(sl-V2X-ConfigDedicated)、车联网移动控制信息(mobilityControlInfoV2X)等。
若在上述步骤601中，用户上下文修改请求消息中携带具有映射关系的远程UE的承载标识和远程UE与中继UE之间的逻辑信道的标识，那么DU还可以在修改中继UE的上下文的过程中，生成针对远程UE的RRC配置信息，即为远程UE生成小区组配置信息。例如，DU根据远程UE的标识、远程UE的承载标识以及逻辑信道的标识，生成该远程UE的RRC配置信息。该远程UE的RRC配置信息中包括远程UE的承载标识与逻辑信道的标识之间的映射关系、DU为远程UE配置的底层信息，还可以包括中继UE的标识。
在该示例中，DU和CU虽然不需要在CU-DU接口上为远程UE建立上下文，但是DU需要为远程UE提供底层配置。例如，DU需要为远程UE分配C-RNTI、本地ID或者SL-RNTI等标识，以及配置远程UE与中继UE之间的PC5接口的资源池。
步骤604，DU向CU发送用户上下文修改响应消息，该用户上下文修改响应消息中携带RRC配置信息。
DU完成修改中继的上下文，并生成中继UE的RRC配置信息后，可以该中继UE的RRC配置信息携带在用户上下文修改响应消息中反馈给CU，以便于CU生成能够发送给中继UE的RRC重配置消息。
在一个示例中，若DU还为远程UE生成了RRC配置信息，那么DU可以在用户上下文修改响应消息中增加一个信元(例如CellGroupConfig-for remote UE)，用于携带针对远程UE的小区组配置。从而DU可以在用户上下文修改响应消息将中继UE的RRC配置信息以及远程UE的RRC配置信息一起发送给CU。
可以理解的是，该用户上下文修改响应消息也是封装在CU-DU接口消息(例如，5G系统中的F1消息)中，基于中继UE在CU-DU接口的标识，通过DU与CU之间的CU-DU 接口发送至CU。
步骤605，CU生成RRC重配置消息。
在该示例中，用户上下文修改响应消息携带中继UE的RRC配置信息，和远程UE的RRC配置信息。CU根据中继UE的RRC配置信息，为中继UE生成RRC重配置消息，根据远程UE的RRC配置信息为远程UE生成RRC重配置消息。
步骤606，CU发送RRC重配置消息。
CU将中继UE的RRC重配置消息通过DU发送给中继UE，将远程UE的RRC重配置消息通过DU和中继UE的转发给远程UE。
CU和DU之间传输RRC消息时，都是封装在下行RRC信息传输(DL RCC message transfer)消息或者上行RRC信息传输(UL RCC message transfer)消息中进行传输。示例性的，RRC消息是指与RRC控制相关的消息，例如，RRC连接请求消息、RRC连接建立消息、RRC恢复请求消息、RRC恢复消息、RRC安全模式完成消息、RRC重配置消息、RRC连接完成消息、RRC重建立消息等。
下行RRC信息传输消息和上行RRC信息传输消息的信元结构一般为：UE在CU-DU接口的标识、SRB标识以及RRC容器(RRC-container)。UE在CU-DU接口的标识可以包括CU-DU接口的CU侧标识和DU侧标识，用于CU和DU识别该消息是针对哪个UE的消息，相当于为该UE建立CU与DU之间的传输RRC消息的通道。RRC容器用于携带具体的RRC消息，SRB标识用于指示DU通过和该SRB标识对应的逻辑信道(DU和CU与UE之间的逻辑信道)向UE发送RRC消息，或者用于CU将RRC消息送到SRB标识对应的PDCP实体。
当CU向中继UE发送中继UE的RRC重配置消息时，CU需要在该中继UE的RRC重配置消息外部封装PDCP层，得到中继UE的下行RRC信息。示例性的，若CU和中继UE的协议栈采用上述方案二设置适配层，那么CU还需要继续在该PDCP层外部封装适配信息，该适配信息可以包括中继UE的标识，用来指示该RRC重配置消息是中继UE的。然后CU将得到的下行RRC信息携带在下行RRC信息传输消息的RRC容器中发送给DU。该下行RRC信息传输消息携带的CU-DU接口标识为中继UE在CU-DU接口的标识。
DU获取到中继UE的下行RRC信息后为中继UE的下行RRC消息继续封装RCL层、MAC层以及PHY层。即若该下行RRC信息中封装有适配信息，DU则在适配信息外部封装RLC层、MAC层以及PHY层。若该下行RRC信息中没有封装适配信息，DU则在PDCP层外部封装RLC层、MAC层以及PHY层。
DU通过中继UE的SRB1对应的逻辑信道将封装了该中继UE的RRC重配置消息的下行RRC信息发送给中继UE。中继UE从该下行RRC信息中获取到该中继UE的RRC重配置消息后，即可根据该RRC重配置消息的指示，获知中继UE的承载标识、中继UE与远程UE2之间的逻辑信道的标识这两者之间的映射关系，或者中继UE的承载标识、远程UE2的承载标识、中继UE与远程UE2之间的逻辑信道的标识这三者之间的映射关系。并在后续为远程UE2提供中继服务时，基于获知的映射关系对远程UE2与CU之间的数据包以及RRC消息进行转发。
以远程UE2为例，当CU向远程UE发送远程UE2的RRC重配置消息时，CU为远程UE2的RRC重配置消息封装PDCP层和适配信息(即RRC重配置消息外部封装了PDCP 层，PDCP层的外部封装了适配信息)，得到远程UE2的下行RRC信息。示例性的，该适配信息用来指示当前传输的RRC重配置消息是远程UE2的RRC重配置消息，该适配信息可以包括远程UE2的标识以及远程UE2与中继UE之间的逻辑信道的标识(假设为LCID4)。或者，若在上述步骤603中DU为中继UE生成的配置信息中包括中继UE的承载标识、远程UE2的承载标识、以及中继UE与远程UE2之间的逻辑信道的标识这三者之间的映射关系，那么该适配信息也可以包括远程UE2的标识和远程UE2的SRB的标识(假设为远程UE2的SRB2的标识)。然后CU将该远程UE2的下行RRC信息携带在下行RRC信息传输消息的RRC容器中发送给DU。由于CU和DU没有为远程UE2建立上下文，远程UE2没有在CU-DU接口的标识。因此在发送远程UE的RRC重配置消息时，使用的下行RRC信息传输消息所携带的CU-DU接口标识仍为中继UE在CU-DU接口的标识。
如果中继UE和CU的协议栈采用上述方案一设置适配层，那么为了使得中继UE获知该远程UE的下行RRC消息外部封装有适配信息，CU可以在封装远程UE2的下行RRC信息的下行RRC信息传输消息中增加第一指示，用来指示该远程UE2的下行RRC消息外部封装有适配信息。示例性的，该第一指示可以是适配层指示(adaptation layer indication)，也可以是中继指示(relay indication)。在本申请中，第一指示携带在CU与DU之间交互消息(例如，上行/下行RRC信息传输消息、上行/下行GTP-U帧)中，用来指示当前传输的RRC消息或者数据包外部封装有适配信息。
在这种情况下，DU获取到CU发送的远程UE2的下行RRC信息后，为远程UE2的下行RRC信息封装PHY层、MAC层以及RLC层时，可以根据下行RRC信息传输消息中携带的第一指示，在该PHY层、MAC层或者RLC层中添加第三指示。最后将封装好的该远程UE2的下行RRC信息发送给中继UE。即DU发送给中继UE的下行RRC信息包括该远程UE2的RRC重配置消息，封装在该RRC重配置消息外部的PDCP层、封装在PDCP层外部的适配信息、封装在适配信息外部的RLC层、封装在RLC层外部的MAC层以及封装在MAC层外部的PHY层。
在本申请中，第三指示是中继UE或者DU添加在PHY层、MAC层或者RLC层中指示，用来指示当前传输的RRC消息或者数据包外部封装有适配信息。
中继UE接收到DU发送的远程UE2的下行RRC信息后，在删除该下行RRC信息的PHY层、MAC层、RLC层的过程中，获取到第三指示，从而中继UE即可根据第三指示确定该下行RRC信息中包括适配信息。那么中继UE在删除该下行RRC信息的PHY层、MAC层、RLC层后，读取适配信息，并确定该下行RRC信息中封装的RRC消息为远程UE2的RRC重配置消息。
示例性的，若适配信息中携带的是远程UE2的标识和LCID4，则中继UE通过逻辑信道LCID4将该下行RRC信息发送给远程UE2。若适配信息中携带的是远程UE2的标识和远程UE2的SRB2的标识，则中继UE根据之前接收到的该中继UE的RRC重配置消息指示的如表1所示的映射关系，确定由逻辑信道LCID4向远程UE2发送该下行RRC信息。
基于图4所示的协议栈可知，中继UE从DU接收到的下行RRC信息包括中继UE与DU之间Uu接口的PHY层、MAC层、RLC层。那么中继UE在向远程UE2发送该下行 RRC信息时，需要删除Uu接口PHY层、MAC层、RLC层，并重新封装该中继UE与远程UE2之间的PC5接口的PHY层、MAC层、RLC层。
可以理解的是，如果中继UE和CU的协议栈采用上述方案二设置适配层，CU则无需在携带远程UE2的下行RRC信息的下行RRC信息传输消息中添加第一指示，从而DU也无需在该下行RRC信息中的PHY层、MAC层或者RLC层中添加第三指示。中继UE在接收到任何一个下行RRC信息时都会读取该下行RRC信息中的适配信息，确定接收到下行RRC信息中封装的下行RRC消息是哪个UE的，并根据适配信息转发下行RRC信息。
至此，即可认为远程UE2通过中继UE向CU-DU架构下的基站请求建立RRC连接、恢复RRC连接，或者重建立RRC连接的过程完成。之后，远程UE2即可通过中继UE与CU进行后续的信息交互。
仍然以远程UE2为例，在后续的信息交互过程中，当远程UE2向CU发送上行RRC消息时，远程UE2为该上行RRC消息封装了PDCP层以及PC5接口的RLC层、MAC层和PHY层，并将得到的上行RRC信息通过PC5接口发送给中继UE。假设远程UE2通过逻辑信道LCID4将该上行RRC信息发送给中继UE。中继UE删除该上行RRC信息中PC5接口的RLC层、MAC层和PHY层后，在该上行RRC信息中的PDCP层外部依次封装适配信息以及Uu接口的RLC层、MAC层和PHY层。该适配信息中可以携带远程UE2的标识和LCID4。然后中继UE根据表1所示映射关系确定与逻辑信道LCID4对应的该中继UE的承载标识为中继UE的SRB1。中继UE通过该中继UE的SRB1对应的中继UE与DU之间的逻辑信道将该上行RRC信息发送给DU。
或者，中继UE根据表1所示映射关系确定逻辑信道LCID4对应的中继UE的承载标识(即中继UE的SRB1)和远程UE2的承载标识(即远程UE2的SRB2)。中继UE在适配信息中携带远程UE2的标识和远程UE2的SRB2的标识。然后该中继UE通过该中继UE的SRB1对应的中继UE与DU之间的逻辑信道将该上行RRC信息发送给DU。
如果中继UE和CU的协议栈采用上述方案一设置适配层，那么为了使得CU获知上行RRC信息中封装有适配信息，中继UE可以在向DU发送上行RRC信息时，在RLC层、MAC层或者PHY层中添加第三指示，以指示该上行RRC消息外部封装有适配信息，使得CU在接收到该上行RRC信息时读取适配信息，以确定该上行RRC信息中上行RRC消息是远程UE2的。
DU接收到上行RRC信息后，删除该上行RRC信息的PHY层、MAC层和RLC层。然后根据第三指示在待发送给CU的上行RRC信息传输消息中携带第一指示，并将上行RRC消息以及封装在该上行RRC消息外部的PDCP层和适配信息携带在该上行RRC信息传输消息的RRC容器，最后将该上行RRC信息传输消息中发送给CU。可选的，该上行RRC信息传输消息还携带该中继UE在CU-DU接口的标识。
CU接收到上行RRC信息后，根据该上行RRC信息传输消息中携带的第一指示，读取该读取该上行RRC信息的适配信息。示例性的，若适配信息中携带远程UE2的标识以及LCID4，那么CU确定该LCID4所对应的远程UE2的SRB为该远程UE2的SRB2。然后CU将上行RRC信息发送到与该远程UE2的SRB2对应的PDCP实体。若适配信息中携带远程UE2的标识以及远程UE2的SRB2的标识，那么CU可以直接该将上行RRC信息发送到与该远程UE2的SRB2对应的PDCP实体。
可以理解的是，如果中继UE和CU的协议栈采用上述方案二设置适配层，中继UE则无需在发送远程UE的上行RRC消息时，在PHY层、MAC层或者RLC层中添加第三指示。从而DU也无需在发送携带该上行RRC消息的上行RRC信息传输消息中增加第一指示。CU接收到任何一个上行RRC信息时都会读取该上行RRC信息中的适配信息，确定接收到上行RRC信息中封装的上行RRC消息是哪个UE的，并根据适配信息向UE的SRB对应的PDCP实体发送上行RRC消息。在这种情况下，中继UE发送自己的上行RRC消息时，封装的适配信息可包括该中继UE的标识。
当CU向远程UE2发送下行RRC消息时，具体过程可以参见上述CU向远程UE2发送远程UE2的RRC重配置消息的过程，此处不再赘述。
对于远程UE2与CU之间的用户面数据传输过程，当远程UE2向CU发送上行数据包时，远程UE2为该上行数据包封装了PDCP层以及PC5接口的RLC层、MAC层和PHY层，并将得到的上行数据信息发送给中继UE。假设远程UE2通过逻辑信道LCID5将该上行数据信息发送给中继UE。中继UE删除该上行数据信息中PC5接口的RLC层、MAC层和PHY层后，在该上行数据信息中的PDCP层外部依次封装适配信息以及Uu接口的RLC层、MAC层和PHY层。该适配信息用于指示上行数据信息中的上行数据包是远程UE2的，该适配信息中可以携带远程UE2的标识和LCID5。然后中继UE根据表1所示映射关系确定与逻辑信道LCID5对应的该中继UE的承载标识为中继UE的DRB3。中继UE通过该中继UE的DRB3对应的中继UE与DU之间的逻辑信道将该上行数据信息发送给DU。
或者，中继UE根据表1所示映射关系确定逻辑信道LCID5对应的中继UE的承载标识(即中继UE的DRB3)和远程UE2的承载标识(即远程UE2的DRB1)。中继UE在适配信息中携带远程UE2的标识和远程UE2的DRB1的标识。然后该中继UE通过该中继UE的DRB3对应的中继UE与DU之间的逻辑信道将该上行数据信息发送给DU。
如果中继UE和CU的协议栈采用上述方案一设置适配层，那么为了使得CU获知该上行数据信息中封装有适配信息，中继UE可以在向DU发送该上行数据信息时，在RLC层、MAC层或者PHY层中添加第三指示，以指示该上行数据信息中包括适配信息，从而使得CU在接收到该上行数据信息时读取适配信息，以确定该上行数据信息中封装的上行数据包是远程UE2的。
DU接收到上行数据信息后，删除该上行数据信息的PHY层、MAC层和RLC层。然后将剩余的上行数据包以及封装在该上行数据包外部的PDCP层和适配信息携带在上行GTP-U帧中发送给CU。在该示例中，由于CU和DU未对远程UE2建立上下文，即远程UE2不具有GTP-U隧道资源。因此DU需要将该上行数据信息封装在中继UE的DRB3所对应的GTP-U隧道的上行GTP-U帧中。即该上行GTP-U帧携带中继UE的DRB3所对应的GTP-U隧道的隧道端点信息。
在该示例中，DU还需要将根据该上行数据信息的PHY层、MAC层或者RLC层中携带的第三指示在该上行GTP-U帧中添加第一指示，以用于指示CU该上行数据信息中包括适配信息。
CU接收到上行数据信息后，根据上行GTP-U帧中携带的第一指示，读取该上行数据信息的适配信息。示例性的，若适配信息中携带远程UE2的标识以及LCID5，那么 CU确定该LCID5所对应的远程UE2的DRB为该远程UE2的DRB1。然后CU将上行数据信息发送到与该远程UE2的DRB1对应的PDCP实体。若适配信息中携带远程UE2的标识以及远程UE2的DRB1的标识，那么CU可以直接该将上行数据信息发送到与该远程UE2的DRB1对应的PDCP实体。
可以理解的是，如果中继UE和CU的协议栈采用上述方案二设置适配层，中继UE则无需在发送远程UE的上行数据信息时，在PHY层、MAC层或者RLC层中添加第一指示。从而DU也无需在发送携带该上行数据信息的上行GTP-U帧中增加第一指示。CU接收到任何一个上行数据信息时都会读取该上行数据信息中的适配信息，确定接收到上行数据信息中的上行数据包是哪个UE的，并根据适配信息向该UE的DRB对应的PDCP实体发送上行数据包。在这种情况下，中继UE发送自己的上行数据包时，封装的适配信息可包括该中继UE的标识。
当CU向远程UE2发送下行数据包时，CU为该下行数据包封装PDCP层以及适配信息，得到该远程UE2的下行数据信息。示例性的，该适配信息包括远程UE2的标识以及远程UE2与中继UE之间的逻辑信道的标识(假设为LCID5)。或者，若在上述步骤603中DU为中继UE生成的配置信息中包括中继UE的承载标识、远程UE2的承载标识、以及中继UE与远程UE2之间的逻辑信道的标识这三者之间的映射关系，那么该适配信息也可以包括远程UE2的标识和远程UE2的DRB的标识(假设为远程UE2的DRB1的标识)。然后CU将该远程UE2的下行数据信息携带在下行GTP-U帧中发送给DU。在该示例中，由于远程UE2不具有GTP-U隧道资源，因此，CU需要确定LCID5、或者LCID5和远程UE2的DRB1的标识对应的中继UE的DBR的标识，即中继UE的DRB3的标识。然后将该下行数据信息封装在中继UE的DRB3所对应的GTP-U隧道的下行GTP-U帧中发送给DU。即该下行GTP-U帧携带中继UE的DRB3所对应的GTP-U隧道的隧道端点信息。
如果中继UE和CU的协议栈采用上述方案一设置适配层，那么为了使得中继UE获知该远程UE2的下行数据包外部封装有适配信息，CU可以在下行GTP-U帧中携带第一指示，用来指示该远程UE2的下行数据包外部封装有适配信息，以便于中继UE读取适配信息并做相应的转发操作。例如，CU可以在类型为下行用户数据(DL user data)的下行GTP-U帧的帧头中添加第一指示。
DU接收到该下行GTP-U帧后，获取CU为远程UE2生成的下行数据信息。然后为该下行数据信息封装PHY层、MAC层以及RLC层，并根据该下行GTP-U帧中携带的第一指示，在PHY层、MAC层或者RLC层中添加第三指示。最后将封装好的下行数据信息发送给中继UE。
中继UE接收到DU发送的下行数据信息后，删除该下行数据信息中由DU封装的Uu接口的PHY层、MAC层以及RLC层，并根据第三指示确定该下行数据信息中存在适配信息。中继UE读取该适配信息，以确定该下行数据信息中封装的下行数据包为远程UE2的下行数据包。
示例性的，若适配信息中携带的是远程UE2的标识和LCID5，则中继UE在删除该适配信息，并在该下行数据信息中的PDCP层外部依次封装PC5接口的PHY层、MAC层、RLC层后，通过远程UE和中继UE之间的逻辑信道LCID5将该下行数据信息发送给远 程UE2。若适配信息中携带的是远程UE2的标识和远程UE2的DRB1的标识，则中继UE根据之前接收到的该中继UE的RRC重配置消息指示的如表1所示的映射关系，确定通过远程UE2和中继UE之间的逻辑信道LCID5向远程UE2发送该下行数据信息。
可以理解的是，如果中继UE和CU的协议栈采用上述方案二设置适配层，CU则无需在携带远程UE2的下行数据包的下行GTP-U帧中添加第一指示，从而DU也需要在该下行数据包的RLC层、MAC层或者PHY层中添加第三指示。中继UE在接收到任何一个下行数据信息时都会读取该下行数据信息中的适配信息，确定接收到下行数据信息中封装的下行数据包是哪个UE的，并根据适配信息转发下行数据信息。在这种情况下，如果CU向中继UE发送中继UE的下行数据包，则可以在封装的适配信息中携带该中继UE的标识。
以上为本申请提供的一种通信方法，用于实现基于CU-DU架构，当适配层部署在CU的协议栈中时，UE-to-Network relay的通信过程。
针对在DU的协议栈中部署适配层的方式，示例性的，以如图7所示的用户面协议栈和如图8所示的控制面协议栈为例，说明在DU的协议栈中部署适配层时，UE-to-Network relay的通信原理。
参见图7，为UE-to-Network relay的通信系统中，远程UE2、中继UE、CU和DU之间的一种可能的用户面协议栈。相比于图3所示的用户面协议栈，适配层部署在DU的协议栈中。
参见图8，为UE-to-Network relay的通信系统中，远程UE2、中继UE、CU和DU之间的一种可能的控制面协议栈。相比于图4所示的控制面协议栈，适配层部署在DU的协议栈中。
示例性的，关于适配层在中继UE和DU的协议栈中的设置方案，本申请提供两种方案，包括如下所述方案三和方案四。
方案三是当传输中继UE的数据包/RRC消息时，DU和中继UE的协议栈中不包括适配层，而当传输远程UE的数据包/RRC消息时，DU和中继UE的协议栈中才会包括适配层。即对于上行而言，中继UE在发送上行数据包/上行RRC消息时，若发送的是中继UE自己的上行数据包/上行RRC消息，中继UE则不需要为该上行数据包/上行RRC消息封装适配信息。若发送的是远程UE的上行数据包/上行RRC消息，中继UE则需为该上行数据包/上行RRC消息封装适配信息，以向DU指示该上行数据包/上行RRC消息是远程UE的。同理，对于下行而言，DU在发送在发送下行数据包/下行RRC消息时，若发送的是中继UE下行数据包/下行RRC消息，DU则不需要为该下行数据包/下行RRC消息封装适配信息。若发送的是远程UE的下行数据包/下行RRC消息，DU则需要为该下行数据包/下行RRC消息封装适配信息，以向中继UE指示该下行数据包/下行RRC消息是远程UE的。由于适配层可能存在或不存在，所以中继或基站有必要在发送每个数据包/RRC消息时指示对方适配层是否存在。
方案四是DU和中继UE的协议栈中始终包括适配层。对于上行而言，中继UE无论是发送自己的数据包/RRC消息，还是转发远程UE的数据包/RRC消息，中继UE都会为发送的数据包/RRC消息封装适配信息，供DU获知中继UE发送的数据包/RRC消息是远程UE的还是中继UE自己。对于下行而言，DU无论通过中继UE向远程UE发送数据包 /RRC消息，还是直接给中继UE发送数据包/RRC消息，DU都会为发送的数据包/RRC消息封装配置信息，供中继UE获知DU下发的数据包/RRC消息发给中继UE的还是发给远程UE。对于方案四，由于适配层一直存在，则中继或基站在发送每个数据包/RRC消息时不需要指示对方适配层是否存在。
那么，基于如图7和图8所示的协议栈，在CU-DU架构中，由于适配层部署在DU的协议栈中，因此DU在向CU发送中继UE发送的数据包/RRC消息之前，需要先判断该数据包/RRC消息是中继UE的，还是哪个远程UE。如图9所示，为基于如图7和图8所示的协议栈，UE-to-Network relay的通信原理示意图。若该数据包/RRC消息是中继UE的(通信路线可以参见图9所示的实线)，对于数据包而言，DU则通过中继UE的GTP-U隧道，将该数据包发送给CU，由CU将该数据包传送到该中继UE的DRB对应的PDCP实体。对于RRC消息，DU则通过中继UE在CU-DU接口的标识，将该RRC消息发送给CU，由CU将该RRC消息传送到该中继UE的PDCP实体。若该数据包/RRC消息，是远程UE1的(通信路线可以参见图9所示的虚线)。对于数据包，若DU根据适配层的适配信息判断该数据包是远程UE1的DRB的数据包，DU则通过远程UE1的DRB所对应的GTP-U隧道，将该数据包发送给CU，由CU将该数据包传送到该远程UE1的DRB所对应的PDCP实体。对于RRC消息，若DU根据适配层的适配信息判断该RRC消息是远程UE1的SRB的数据包，DU则通过远程UE1在CU-DU接口的标识，将该RRC消息发送给CU，由CU将该RRC消息传送到该远程UE1的SRB所对应的PDCP实体。
基于上述通信原理可知，适配层部署在DU侧时，当一个远程UE通过中继UE向CU和DU请求建立RRC连接，或者请求恢复RRC连接，或者请求重建立RRC连接时，CU和DU需要为该远程UE建立上下文，同时需要修改中继UE的上下文，以使得中继UE可以为该远程UE提供中继服务。
示例性的，参见图10，为本申请提供的一种通信方法的一个实施例的流程图，主要描述适配层部署在DU侧时，UE-to-Network relay的通信过程。该方法包括：
步骤1001，CU生成用户上下文修改请求消息，该用户上下文修改请求消息用于请求DU修改中继UE的上下文，该用户上下文修改请求消息中携带远程UE的标识、该中继UE的承载标识以及与该中继UE的承载标识具有映射关系的逻辑信道的标识，该中继UE的承载标识为该中继UE与CU之间的承载的标识，该逻辑信道为该远程UE与该中继UE之间的逻辑信道。
步骤1002，CU向DU发送用户上下文修改请求消息。
步骤1003，DU根据远程UE的标识、中继UE的承载标识以及逻辑信道的标识，生成该中继UE的RRC配置信息，该中继UE的RRC配置信息包括远程UE的标识、中继UE的承载标识与逻辑信道的标识之间的映射关系。
步骤1004，DU向CU发送用户上下文修改响应消息，该用户上下文修改响应消息中携带该中继UE的RRC配置信息。
示例性的，步骤1001-1004的具体实现方式可以参见上述步骤601-604中，CU和DU针对中继UE的上下文的修改以及RRC配置信息的生成过程，此处不再赘述。
步骤1005，CU根据中继UE的RRC配置信息生成中继UE的RRC重配置消息。
步骤1006，CU向中继UE发送该中继UE的RRC重配置消息。
在该示例中，当CU向中继UE发送中继UE的RRC重配置消息时，CU需要在该中继UE的RRC重配置消息外部封装PDCP层，得到中继UE的下行RRC信息。然后CU将得到的下行RRC信息携带在下行RRC信息传输消息的RRC容器中发送给DU。示例性的，下行RRC信息传输消息携带的CU-DU接口标识为中继UE在CU-DU接口的标识。
若中继UE和DU的协议栈采用上述方案三设置适配层，那么DU获取到CU发送的中继UE的下行RRC信息后，即可在该下行RRC信息中的PDCP层外部依次封装RLC层、MAC层以及PHY层。
若中继UE和DU的协议栈采用上述方案四设置适配层，那么DU获取到CU发送的中继UE的下行RRC信息后，即可在该下行RRC信息中的PDCP层外部依次封装适配信息、RLC层、MAC层以及PHY层。此时，该适配信息可以包括中继UE的标识，用来指示该下行RRC信息中封装的RRC重配置消息是中继UE的。
DU通过中继UE的SRB1对应的逻辑信道(中继UE和CU之间的逻辑信道)将封装好的下行RRC信息发送给中继UE。中继UE从该下行RRC信息中获取到该中继UE的RRC重配置消息后，即可根据该RRC重配置消息的指示，获知中继UE的承载标识、中继UE与远程UE2之间的逻辑信道的标识这两者之间的映射关系，或者中继UE的承载标识、远程UE2的承载标识、中继UE与远程UE2之间的逻辑信道的标识这三者之间的映射关系。并在后续为远程UE2提供中继服务时，基于获知的映射关系对远程UE2与CU之间的数据包以及RRC消息进行转发。
步骤1007，CU向DU发送用户上下文建立请求消息。
在该示例中，CU在接收到远程UE的请求消息(例如，RRC连接请求消息，RRC重建立请求消息或者RRC恢复请求消息)后，即可生成用户上下文建立请求消息，用以请求DU为该远程UE建立上下文。
该用户上下文建立请求消息可以包括远程UE的标识、CU为远程UE分配的在CU-DU接口的标识、中继UE的标识、CU为该远程UE的请求增加的SRB列表、DRB列表，以及该远程UE的承载标识与逻辑信道之间的映射关系。
示例性的，远程UE的标识可以是CU接收到远程UE的请求消息中携带的远程UE的标识。例如，该远程UE的标识可以是远程UE的L2ID，也可以是远程UE在该远程UE与中继UE之间的PC5接口的标识，或者是远程UE的L2ID和PC5接口的标识的组合。CU通过接收到的远程UE的标识，确定是远程UE的请求，且由转发该请求消息的中继UE作为中继，为该远程UE提供中继服务。因此，CU需要为该远程UE确定每个逻辑信道(远程UE与中继UE之间的逻辑信道)确定对应的承载，以便于DU为该远程UE建立上行文。
SRB列表可以包括CU为该远程UE请求增加的每个SRB的标识。DRB列表可以包括CU为该远程UE请求增加的每个DRB的标识，以及每个DRB所对应的GTP-U隧道的CU侧的TEID。该远程UE的承载标识为该远程UE与CU之间的承载的标识，即该SRB列表中的SRB的标识和DRB列表中的DRB的标识。逻辑信道是为远程UE和中继UE之间的侧链路的逻辑信道，或该远程UE和该中继UE之间的PC5接口的逻辑信道，远程UE和中继UE通过逻辑信道采用直接传输的方式进行信息交互。
例如，以远程UE2为例，该用户上下文建立请求消息包括远程UE2的标识、CU为 远程UE2分配的在CU-DU接口的标识、CU为远程UE2请求增加的SRB列表(包括远程UE2的SRB1和SRB2的标识)、远程UE2的SRB1的标识与逻辑信道LCID3的映射关系、远程UE2的SRB2的标识与逻辑信道LCID4的映射关系、CU为远程UE2请求增加的DRB列表(包括远程UE2的DRB1和DRB2的标识、远程UE2的DRB1所对应的GTP-U隧道的CU侧的TEID、远程UE2的DRB2所对应的GTP-U隧道的CU侧的TEID、)、远程UE2的DRB1的标识与逻辑信道LCID5的映射关系、远程UE2的DRB2的标识与逻辑信道LCID6的映射关系。
可选的，该用户上下文建立请求消息还携带第二指示，该第二指示用于指示DU在向中继UE发送远程UE的下行数据信息或下行RRC信息时，在下行数据信息或下行RRC信息中增加适配信息，以指示该下行数据信息或下行RRC信息是远程UE的。
该用户上下文建立请求消息可以封装在CU-DU接口消息中发送给DU。例如，在5G系统中，该用户上下文建立请求消息可以封装在F1消息中，CU通过与DU之间的F1接口发送至DU，以请求DU建立远程UE的上下文。
步骤1008，DU根据中继UE的标识、远程UE的标识、远程UE的承载标识与逻辑信道之间的映射关系，生成远程UE的RRC配置信息。
DU接收到用户上下文建立请求消息后，确认CU为远程UE分配的远程UE在CU-DU接口的标识、中继UE的标识、请求增加的SRB列表和DRB列表、以及远程UE的承载标识与逻辑信道之间的映射关系。并为DRB列表中每个DRB分配对应的GTP-U隧道的DU侧的TEID，以及为UE分配的UE在CU-DU接口的DU侧标识，完成远程UE的上下文建立。
同时，DU接收到用户上下文建立请求消息后，还可以为该远程UE提供底层配置，包括为远程UE分配C-RNTI、本地ID或者SL-RNTI等标识，以及配置远程UE与中继UE之间的PC5接口的资源池等底层信息。
DU根据该用户上下文建立请求消息中携带的信息，以及基于该用户上下文请求消息中携带的信息，为远程UE分配的CU-DU接口的DU侧标识、对应的GTP-U隧道的DU侧的TEID、底层信息生成该远程UE的RRC配置信息，例如针对远程UE的小区组配置信息。
步骤1009，DU向CU发送用户上下文建立响应(UE context setup response)消息。
DU将该远程UE的RRC配置信息封装到用户上下文建立响应消息中反馈给CU。从而完成对远程UE的上下文建立。
步骤1010，CU根据远程UE的RRC配置信息生成远程UE的RRC重配置消息。
步骤1011，CU向远程UE发送该远程UE的RRC重配置消息。
以远程UE2为例，当CU向远程UE2发送该远程UE2的RRC重配置消息时，CU为远程UE2的RRC重配置消息封装PDCP层，得到远程UE2的下行RRC信息。然后将该下行RRC信息携带在下行RRC信息传输消息的RRC容器中发送给DU。在该示例中，由于CU和DU为远程UE2建立上下文，远程UE2具有在CU-DU接口的标识。因此在发送远程UE2的RRC重配置消息时，该下行RRC信息传输消息携带的CU-DU接口标识为远程UE2在CU-DU接口的标识。
DU接收该下行RRC信息传输消息后，获取该远程UE2的下行RRC信息，然后在该下行RRC信息中的PDCP层外部依次封装适配信息、RLC层、MAC层以及PHY层。最后通过中继UE的SRB1对应的逻辑信道(中继UE与DU之间的逻辑信道)，将封装好的远程UE2的下行RRC信息发送给中继UE。
示例性的，该适配信息用来指示该下行RRC信息中封装的RRC重配置消息是远程UE2的RRC重配置消息，该适配信息可以括远程UE2的标识以及远程UE2与中继UE之间的逻辑信道的标识(假设为LCID3)。或者，若在DU为中继UE生成的配置信息中包括中继UE的承载标识、远程UE2的承载标识、以及中继UE与远程UE2之间的逻辑信道的标识这三者之间的映射关系，那么该适配信息也可以包括远程UE2的标识和远程UE2的承载标识(假设为远程UE2的SRB1的标识)。
若中继UE和DU的协议栈采用上述方案三设置适配层，那么为了使得中继UE获知DU发送的下行RRC信息中封装有适配信息，DU可以在RLC层、MAC层或者PHY层中增加第三指示，用来指示该下行RRC信息中包括适配信息，以便于中继UE读取该下行RRC信息中的适配信息，进而基于读取的适配信息转发远程UE2的RRC重配置消息。
中继UE接收到DU发送下行RRC信息后，在删除该下行RRC信息中DU封装的Uu接口的PHY层、MAC层、RLC层的过程中，获取到第三指示，从而中继UE根据第三指示确定该下行RRC信息中包括适配信息。那么中继UE在删除该下行RRC信息中的Uu接口的PHY层、MAC层、RLC部后，读取适配信息，并确定该下行RRC信息中封装的RRC重配置消息为远程UE2的RRC重配置消息。
示例性的，若适配信息中携带的是远程UE2的标识和LCID3，则中继UE在删除该适配信息，并在该下行RRC信息中的PDCP层外部封装PC5接口的PHY层、MAC层、RLC部后，通过逻辑信道LCID3将该下行RRC信息发送给远程UE2。若适配信息中携带的是远程UE2的标识和远程UE2的SRB1的标识，则中继UE根据之前接收到的该中继UE的RRC重配置消息指示的如表1所示的映射关系，确定由逻辑信道LCID3向远程UE2发送该远程UE2的下行RRC信息。
可以理解的是，如果中继UE和DU的协议栈采用上述方案四设置适配层，DU则在向中UE发送远程UE2的下行RRC信息时，无需在RLC层、MAC层或者PHY层中添加第三指示。中继UE在接收到任何一个下行RRC信息时都会读取该下行RRC信息中的适配信息，确定接收到下行RRC信息中封装的下行RRC消息是哪个UE的，并根据适配信息转发下行RRC信息。
至此，即可认为远程UE2通过中继UE向CU-DU架构下的基站请求建立RRC连接、恢复RRC连接，或者重建立RRC连接的过程完成。之后，远程UE2即可通过中继UE与CU进行后续的信息交互。
仍然以远程UE2为例，在后续的信息交互过程中，当远程UE2向CU发送上行RRC消息时，远程UE2为该上行RRC消息封装PDCP层以及PC5接口的RLC层、MAC层和PHY层，并将得到的上行RRC信息发送给中继UE。假设该上行RRC消息为远程UE2的SRB1上传输的RRC消息，远程UE2则可以根据之前接收到的RRC重配置消息指示的该远程UE2的承载标识与远程UE2和中继UE之间的逻辑信道的标识之间的映射关系，确定可以通过逻辑信道LCID3来发送远程UE2的SRB1上传输的RRC消息。那么远程UE2可以 通过逻辑信道LCID3将该上行RRC信息发送给中继UE。
中继UE删除该上行RRC信息中PC5接口的RLC层、MAC层和PHY层后，在该上行RRC信息中的PDCP层外部依次封装适配信息以及Uu接口的RLC层、MAC层和PHY层。该适配信息中可以携带远程UE2的标识和LCID3。然后中继UE根据表1所示映射关系确定与逻辑信道LCID3对应的该中继UE的承载标识为中继UE的SRB1。中继UE通过该中继UE的SRB1对应的中继UE与DU之间的逻辑信道将该上行RRC信息发送给DU。
或者，中继UE根据表1所示映射关系确定逻辑信道LCID3对应的中继UE的承载标识(即中继UE的SRB1)和远程UE2的承载标识(即远程UE2的SRB1)。中继UE在适配信息中携带远程UE2的标识和远程UE2的SRB1的标识。然后该中继UE通过该中继UE的SRB1对应的中继UE与DU之间的逻辑信道将该上行RRC信息发送给DU。
如果中继UE和DU的协议栈采用上述方案三设置适配层，那么为了使得DU获知该上行RRC消息外部封装有适配信息，中继UE可以在该上行RRC消息的Uu接口的RLC层、MAC层或者PHY层中添加第三指示，以指示该上行RRC消息外部封装有适配信息，使得DU在接收到上行RRC信息时读取适配信息，以确定该上行RRC信息中封装的上行RRC消息是远程UE2的。
DU接收到上行RRC信息后，根据该上行RRC信息的PHY层、MAC层或者RLC层中携带的第三指示确定该上行RRC信息包括适配信息。DU在删除该上行RRC信息的PHY层、MAC层和RLC层后，读取该上行RRC信息的适配信息。
示例性的，若适配信息中携带远程UE2的标识以及LCID3，那么DU可以根据如表1所示的映射关系，确定中继UE的SRB2的标识和/或LCID3对应的远程UE2的SRB的标识，即远程UE2的SRB1的标识。若适配信息中携带远程UE2的标识以及远程UE的SRB1的标识，DU则可以直接从该适配信息中获取远程UE的SRB1的标识。
然后，DU将上行RRC消息、封装在该上行RRC消息外部的PDCP层、远程UE2在CU-DU接口的标识、远程UE2的SRB1的标识封装在上行RRC信息传输消息中发送给CU。
CU接收到该上行RRC信息传输消息后，获取携带的远程UE2的上行RRC信息，并根据该上行RRC信息传输消息携带的远程UE2的SRB1的标识，将该上行RRC信息发送到与该远程UE2的SRB1对应的PDCP实体中。
可以理解的是，如果中继UE和DU的协议栈采用上述方案四设置适配层，中继UE则无需在发送远程UE的上行RRC消息时，在Uu接口的PHY层、MAC层或者RLC层中添加第三指示。DU接收到中继UE发送的任何一个上行RRC信息时都会读取该上行RRC信息中的适配信息，确定接收到上行RRC信息中封装的上行RRC消息是哪个UE的。在这种情况下，中继UE发送自己的上行RRC消息时，外部封装的适配信息可包括该中继UE的标识。
当CU向远程UE2发送下行RRC消息时，具体过程可以参见上述步骤1011中CU向远程UE2发送远程UE2的RRC重配置消息的过程，此处不再赘述。
对于远程UE2与CU之间的用户面数据传输过程，当远程UE2向CU发送上行数据包时，远程UE2为该上行数据包封装PDCP层以及PC5接口的RLC层、MAC层和PHY层，并将得到的上行数据信息发送给中继UE。假设该上行数据包是远程UE2的DRB1上传输的数据包，远程UE2通过之前接收到的RRC重配置消息指示的该远程UE2的承载标 识与逻辑信道的标识之间的映射关系，确定通过逻辑信道LCID5将该上行数据信息发送给中继UE。中继UE删除该上行数据信息中PC5接口的RLC层、MAC层和PHY层后，在该上行数据信息中的PDCP层外部依次封装适配信息以及Uu接口的RLC层、MAC层和PHY层。该适配信息用于指示上行数据信息中的上行数据包是远程UE2的，该适配信息可以携带远程UE2的标识和LCID5。然后中继UE根据表1所示映射关系确定与逻辑信道LCID5对应的该中继UE的承载标识为中继UE的DRB3。中继UE通过该中继UE的DRB3对应的中继UE与DU之间的逻辑信道将该上行数据信息发送给DU。
或者，中继UE根据表1所示映射关系确定逻辑信道LCID5对应的中继UE的承载标识(即中继UE的DRB3)和远程UE2的承载标识(即远程UE2的DRB1)。中继UE在适配信息中携带远程UE2的标识和远程UE2的DRB1的标识。然后该中继UE通过该中继UE的DRB3对应的中继UE与DU之间的逻辑信道将该上行数据信息发送给DU。
如果中继UE和DU的协议栈采用上述方案三设置适配层，那么为了使得DU获知该远程UE2的上行数据包的外部封装有适配信息，中继UE可以在该上行数据包的Uu接口的RLC层、MAC层或者PHY层中添加第三指示，以指示该上行数据包的外部封装有适配信息，从而使得DU在接收到上行数据信息时读取适配信息，以确定该上行数据信息中上行数据包是远程UE2的。
DU接收到上行数据信息后，根据该上行数据信息的PHY层、MAC层或者RLC层中携带的第三指示确定该上行数据信息包括适配信息。DU读取该上行数据信息的适配信息，确定该上行数据信息中封装的上行数据包是远程UE2的。若适配信息中携带远程UE2的标识以及LCID5，那么DU可以根据如表1所示的映射关系，确定中继UE的DRB3的标识和LCID5所对应的远程UE2的DRB的标识，即远程UE2的DRB1的标识。进而DU将删除了PHY层、MAC层和RLC层以及的上行数据信息(即包括上行数据包以及封装在该上行数据包外部的PDCP层)携带在远程UE2的DRB1对应的上行GTP-U帧中发送给CU。即该上行GTP-U帧携带远程UE2的DRB1所对应的GTP-U隧道的隧道端点信息。若适配信息中携带远程UE2的标识和远程UE2的DRB1的标识，DU则可以直接将删除了PHY层、MAC层和RLC层以及适配信息的上行数据信息携带在远程UE2的DRB1对应的上行GTP-U帧中发送给CU。
可以理解的是，如果中继UE和DU的协议栈采用上述方案四设置适配层，中继UE则无需在发送远程UE的上行数据包时，在PHY层、MAC层或者RLC层中添加第三指示。DU接收到任何一个上行数据信息时都会读取该上行数据信息中的适配信息，确定接收到上行数据信息中封装的上行数据包是哪个UE的。在这种情况下，中继UE发送自己的上行数据包时，外部封装的适配信息可包括该中继UE的标识。
CU接收到上行GTP-U帧后，获取上行数据信息。然后将该上行数据信息发送到与该远程UE2的DRB1对应的PDCP实体。
当CU向远程UE2发送下行数据包时，CU为该下行数据包封装PDCP层，得到下行数据信息。假设该下行数据包为远程UE2的DRB1传输的数据包，CU则将该下行数据信息携带在远程UE2的DRB1对应的下行GTP-U帧中发送给DU，即该下行GTP-U帧中携带远程UE2的DRB1所对应的GTP-U隧道的隧道端点信息。
DU接收到该下行GTP-U帧后，获取携带的下行数据信息。然后在该下行数据信息 中的PDCP层外部依次封装适配信息以及Uu接口的RLC层、MAC层以及PHY层。最后DU通过中继UE的DRB3对应的逻辑信道(中继UE与DU之间的逻辑信道)，将封装好的远程UE2的下行RRC信息发送给中继UE。示例性的，该适配信息用于指示该下行数据信息中封装的下行数据包是远程UE2的下行数据包，该适配信息可以包括远程UE2的标识以及逻辑信道的标识。例如，该逻辑信道的标识为远程UE2的DRB1对应的LCID5。或者，若在DU为中继UE生成的配置信息中包括中继UE的承载标识、远程UE2的承载标识、以及中继UE与远程UE2之间的逻辑信道的标识这三者之间的映射关系，该适配信息也可以包括远程UE2的标识和远程UE2的DRB1的标识。
如果中继UE和DU的协议栈采用上述方案三设置适配层，那么为了使得中继UE获知该远程UE2的下行数据包外部封装有适配信息，DU可以在Uu接口的RLC层、MAC层或者PHY层中添加第三指示，用来向中继UE指示该下行数据包外部封装有适配信息，从而使得中继UE读取该适配信息。
中继UE接收到DU发送的下行数据信息后，删除该下行数据信息中由DU封装的Uu接口的PHY层、MAC层以及RLC层，并根据第三指示确定该下行数据信息中存在适配信息。中继UE读取该适配信息，以确定该下行数据信息中封装的下行数据包为远程UE2的下行数据包。
示例性的，若适配信息中携带的是远程UE2的标识和LCID5，则中继UE在删除该适配信息，并在该下行数据信息中的PDCP层外部依次封装PC5接口的PHY层、MAC层、RLC层后，通过中继UE与远程UE2之间的逻辑信道LCID5将该下行数据信息发送给远程UE2。若适配信息中携带的是远程UE2的标识和远程UE2的DRB1的标识，则中继UE根据之前接收到的该中继UE的RRC重配置消息指示的如表1所示的映射关系，确定通过远程UE2和中继UE之间的由逻辑信道LCID5向远程UE2发送该下行数据信息。
可以理解的是，如果中继UE和DU的协议栈采用上述方案四设置适配层，DU则无需远程UE2的下行数据包的PHY层、MAC层或者RLC层中添加第三指示。中继UE在接收到任何一个下行数据信息时都会读取该下行数据信息中的适配信息，确定接收到下行数据信息中的下行数据包是哪个UE的，并根据适配信息转发下行数据信息。在这种情况下，如果DU向中继UE发送中继UE的下行数据包，则可以在封装的适配信息中携带该中继UE的标识，以指示该下行数据信息是中继UE的。
以上为本申请提供的一种通信方法，用于实现基于CU-DU架构，当适配信息部署在DU侧时，UE-to-Network relay的通信过程。
下面介绍本申请实施例提供的一种通信装置1100。如图11所示：该通信装置1100包括处理单元1101和通信单元1102。可选的，该通信装置1100还包括存储单元1103。处理单元1101、通信单元1102和存储单元1103通过通信总线1104相连。
处理单元1101可以包括至少一个处理器，其中，处理器可以包括如下至少一种类型：通用中央处理器(Central Processing Unit，CPU)、数字信号处理器(Digital Signal Processor，DSP)、微处理器、特定应用集成电路专用集成电路(Application-Specific Integrated Circuit，ASIC)、微控制器(Microcontroller Unit，MCU)、现场可编程门阵列(Field Programmable Gate Array，FPGA)、或者用于实现逻辑运算的集成电路。例如，处理器可以是一个单核(single-CPU)处理器 或多核(multi-CPU)处理器。其可以实现或执行结合本申请实施例公开内容所描述的各种示例性的逻辑方框，模块和电路。处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。
通信单元1102可以是具有收发功能的功能模块，用于与CU、DU或者UE进行信息交换。
存储单元1103可以包括一个或者多个存储器，存储器可以是一个或者多个设备、电路中用于存储程序或者数据的器件。存储单元1103可以独立存在，通过通信总线1104与处理单元1101相连。存储单元1103也可以与处理单元1104集成在一起。
其中，存储器可以包括如下至少一种类型：只读存储器(read-only memory，ROM)或可存储静态信息和指令的其他类型的静态存储设备，随机存取存储器(random access memory，RAM)或者可存储信息和指令的其他类型的动态存储设备，也可以是电可擦可编程只读存储器(Electrically erasable programmabler-only memory，EEPROM)。在某些场景下，存储器还可以是只读光盘(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、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质，但不限于此。
通信总线1104可以是外设部件互连标准(Peripheral Component Interconnect，PCI)总线或扩展工业标准结构(Extended Industry Standard Architecture，EISA)总线等。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图11中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
通信装置1100可以用于CU、DU、电路、硬件组件或者芯片中。
可选的，该通信装置1100可以是本申请实施例中的CU。该通信单元1102可以是网络接口(例如，包括CU与DU之间的F1接口)，该处理单元1101例如可以是处理器，存储单元1103例如可以是存储器。当该CU包括存储单元1103时，该存储单元1103用于存储计算机执行指令，该处理单元1101与该存储单元1103连接，该处理单元1101执行该存储单元1103存储的计算机执行指令，以使该CU执行上述实施例中CU执行的方法，包括上述图6、图10所示实施例中CU执行的相关步骤，以及本文中描述的技术的其他CU执行的过程。上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
当处理单元1101为处理器1201，通信单元1102为网络接口1202，存储单元1103为存储器1203时，本申请所涉及的CU可以为图12所示的CU。
可选的，通信装置1100可以是本申请实施例中的CU中的芯片。通信单元1102可以是输入或者输出接口、管脚或者电路等。可选的，存储单元1101可以存储CU侧的方法的计算机执行指令，以使处理单元1101执行上述实施例中CU执行的方法，包括上述图6、图10所示实施例中CU执行的相关步骤，以及本文中描述的技术的其他CU执行的过程。存储单元1103可以是寄存器、缓存或者RAM等，存储单元1103可以和处理单元1101集成在一起；存储单元1103可以是ROM或者可存储静态信息和指令的其他类型的静态存储设备，存储单元1103可以与处理单元1101相独立。
可选的，该通信装置1100可以是本申请实施例中的DU。该通信单元1102可以包括网络接口(例如，包括CU与DU之间的F1接口)、天线和收发机，该处理单元1101例如可以是处理器，存储单元1103例如可以是存储器。当该DU包括存储单元1103时，该存储单元1103用于存储计算机执行指令，该处理单元1101与该存储单元1103连接，该处理单元1101执行该存储单元1103存储的计算机执行指令，以使该DU执行的方法，包括上述图6、图10所示实施例中DU执行的相关步骤，以及本文中描述的技术的DU执行的其他过程。上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
当处理单元1101为处理器1301，通信单元1102包括网络接口1302a、收发机1302b以及天线1302c，存储单元1103为存储器1303时，本申请所涉及的DU可以为图13所示的DU。可选的，随着无线通信技术的发展，收发机、网络接口可以被集成在通信装置上，例如通信单元1102集成了网络接口1302a和收发机1302b。
可选的，通信装置1100可以是本申请实施例中的DU中的芯片。通信单元1102可以是输入或者输出接口、管脚或者电路等。可选的，存储单元1101可以存储DU侧的方法的计算机执行指令，以使处理单元1101执行上述实施例中DU执行的方法，包括上述图6、图10所示实施例中DU执行的相关步骤，以及本文中描述的技术的DU执行的其他过程。存储单元1103可以是寄存器、缓存或者RAM等，存储单元1103可以和处理单元1101集成在一起；存储单元1103可以是ROM或者可存储静态信息和指令的其他类型的静态存储设备，存储单元1103可以与处理单元1101相独立。
本申请实施例还提供了一种计算机可读存储介质。上述实施例中描述的方法可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。如果在软件中实现，则功能可以作为一个或多个指令或代码存储在计算机可读介质上或者在计算机可读介质上传输。计算机可读介质可以包括计算机存储介质和通信介质，还可以包括任何可以将计算机程序从一个地方传送到另一个地方的介质。存储介质可以是可由计算机访问的任何可用介质。
作为一种可选的设计，计算机可读介质可以包括RAM，ROM，EEPROM，CD-ROM或其它光盘存储器，磁盘存储器或其它磁存储设备，或可用于承载的任何其它介质或以指令或数据结构的形式存储所需的程序代码，并且可由计算机访问。而且，任何连接被适当地称为计算机可读介质。例如，如果使用同轴电缆，光纤电缆，双绞线，数字用户线(DSL)或无线技术(如红外，无线电和微波)从网站，服务器或其它远程源传输软件，则同轴电缆，光纤电缆，双绞线，DSL或诸如红外，无线电和微波之类的无线技术包括在介质的定义中。如本文所使用的磁盘和光盘包括光盘(CD)，激光盘，光盘，数字通用光盘(DVD)，软盘和蓝光盘，其中磁盘通常以磁性方式再现数据，而光盘利用激光光学地再现数据。上述的组合也应包括在计算机可读介质的范围内。
本申请实施例还提供了一种计算机程序产品。上述实施例中描述的方法可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。如果在软件中实现，可以全部或者部分得通过计算机程序产品的形式实现。计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行上述计算机程序指令时，全部或部分地产生按照上述方法实施例中描述的流程或功能。上述计算机可以是通用计算机、专用计算机、计算 机网络、网络设备、用户设备或者其它可编程装置。
以上所述的具体实施方式，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明的具体实施方式而已，并不用于限定本发明的保护范围，凡在本发明的技术方案的基础之上，所做的任何修改、等同替换、改进等，均应包括在本发明的保护范围之内。

Claims (25)

  1. 一种通信方法，其特征在于，包括：
    集中式单元CU生成用户上下文修改请求消息，所述用户上下文修改请求消息用于请求分布式单元DU修改中继用户设备UE的上下文，所述用户上下文修改请求消息中携带远程UE的标识、所述中继UE的承载标识以及与所述中继UE的承载标识具有映射关系的逻辑信道的标识，所述中继UE的承载标识为所述中继UE与所述CU之间的承载的标识，所述逻辑信道为所述远程UE与所述中继UE之间的逻辑信道；
    所述CU向所述DU发送所述用户上下文修改请求消息。
  2. 根据权利要求1所述的方法，其特征在于，所述用户上下文修改请求消息中还携带与所述中继UE的承载标识和所述逻辑信道的标识具有映射关系的所述远程UE的承载标识，所述远程UE的承载标识为所述远程UE与所述CU之间的承载的标识。
  3. 根据权利要求1或2所述的方法，其特征在于，所述方法还包括：
    所述CU向所述DU发送下行无线资源控制RRC信息传输消息，所述下行RRC信息传输消息包括所述远程UE的下行RRC信息、所述中继UE在CU-DU接口的标识、第一指示，所述下行RRC信息包括所述远程UE的下行RRC消息以及封装在所述下行RRC消息外部的分组数据汇聚协议PDCP层和适配信息，适配信息用于指示所述下行RRC消息为所述远程UE的下行RRC消息，第一指示用于指示所述下行RRC消息外部封装有适配信息。
  4. 根据权利要求1-3任一项所述的方法，其特征在于，所述方法还包括：
    所述CU接收所述DU发送的上行RRC信息传输消息，所述上行RRC信息传输消息包括所述远程UE的上行RRC信息、所述中继UE在CU-DU接口的标识、第一指示，所述上行RRC信息包括所述远程UE的上行RRC消息以及封装在所述上行RRC消息外部的PDCP层和适配信息，适配信息用于指示所述上行RRC消息为所述远程UE的上行RRC消息，第一指示用于指示所述上行RRC消息外部封装有适配信息。
  5. 根据权利要求1-4任一项所述的方法，其特征在于，所述方法还包括：
    所述CU向所述DU发送下行通用分组无线服务技术隧道协议GTP-U帧，所述下行GTP-U帧包括所述远程UE的下行数据信息、第一指示、所述中继UE的GTP-U隧道的隧道端点标识，所述下行数据信息包括所述远程UE的下行数据包以及封装在所述下行数据包外部的PDCP层和适配信息，适配信息用于指示所述下行数据包为所述远程UE的下行数据包，第一指示用于指示所述下行数据包外部封装有适配信息。
  6. 根据权利要求1-5任一项所述的方法，其特征在于，所述方法还包括：
    所述CU接收所述DU发送的上行GTP-U帧，所述上行GTP-U帧包括所述远程UE的上行数据信息、第一指示、所述中继UE的GTP-U隧道的隧道端点标识，所述上行数据信息包括所述远程UE的上行数据包以及封装在所述上行数据包外部的PDCP层和适配信息，适配信息用于指示所述上行数据包为所述远程UE的上行数据包，第一指示用于指示所述上行数据包外部封装有适配信息。
  7. 根据权利要求1或2所述的方法，其特征在于，所述方法还包括：
    所述CU向所述DU发送用户上下文建立请求消息，所述用户上下文建立请求消息包括所述中继UE的标识、所述远程UE的标识、所述远程UE的承载标识与所述逻辑信 道之间的映射关系，所述用户上下文建立请求消息用于请求所述DU建立所述远程UE的上下文。
  8. 根据权利要求7所述的方法，其特征在于，所述用户上下文修改请求消息还携带第二指示，所述第二指示用于指示所述DU在发送所述远程UE的下行数据信息或下行RRC信息时，在所述下行数据信息或下行RRC信息中增加适配信息，适配信息用于指示所述下行数据或下行RRC信息为所述远程UE的下行数据信息或下行RRC信息。
  9. 根据权利要求1-8任一项所述的方法，其特征在于，所述CU生成用户上下文修改请求消息之前，所述方法还包括：
    所述CU从所述DU接收由所述中继UE转发的所述远程UE的RRC连接建立请求消息、RRC重建立请求消息或者RRC恢复请求消息。
  10. 一种通信方法，其特征在于，所述方法包括：
    分布式单元DU接收集中式单元CU发送的用户上下文修改请求消息，所述用户上下文修改请求消息中携带远程UE的标识、所述中继UE的承载标识以及与所述中继UE的承载标识具有映射关系的逻辑信道的标识，所述中继UE的承载标识为所述中继UE与所述CU之间的承载的标识，所述逻辑信道为所述远程UE与所述中继UE之间的逻辑信道；
    所述DU根据所述远程UE的标识、所述中继UE的承载标识以及所述逻辑信道的标识，生成所述中继UE的无线资源控制RRC配置信息，所述RRC配置信息包括远程UE的标识、所述中继UE的承载标识与所述逻辑信道的标识之间的映射关系。
  11. 根据权利要求10所述的方法，其特征在于，所述用户上下文修改请求消息中还携带与所述中继UE的承载标识和所述逻辑信道的标识具有映射关系的所述远程UE的承载标识，所述远程UE的承载标识为所述远程UE与所述CU之间的承载的标识；
    所述中继UE的承载标识与所述逻辑信道的标识之间的映射关系，具体为：所述中继UE的承载标识、所述逻辑信道的标识以及所述远程UE的承载标识之间的映射关系。
  12. 根据权利要求10或11所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述CU发送下行无线资源控制RRC信息传输消息，所述下行RRC信息传输消息包括所述远程UE的下行RRC信息、所述中继UE在CU-DU接口的标识、第一指示，所述下行RRC信息包括所述远程UE的下行RRC消息以及封装在所述下行RRC消息外部的分组数据汇聚协议PDCP层和适配信息，适配信息用于指示所述下行RRC消息为所述远程UE的下行RRC消息，第一指示用于指示所述下行RRC消息外部封装有适配信息；
    所述DU向所述中继UE发送封装了无线链路控制RLC层、介质访问控制MAC层以及物理PHY层的所述下行RRC信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示所述下行RRC消息外部封装有适配信息。
  13. 根据权利要求10-12任一项所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述中继UE发送的所述远程UE的上行RRC信息，所述上行RRC信息包括所述远程UE的上行RRC消息，以及封装在所述上行RRC消息外部的PDCP层、适配信息、RCL层、MAC层以及PHY层，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示所述上行RRC消息外部封装有适配信息，适配信息用于指示所述上行 RRC消息是所述远程UE的上行RRC消息；
    所述DU向所述CU发送上行RRC信息传输消息，所述上行RRC信息传输消息包括所述中继UE在CU-DU接口的标识、第一指示、所述上行RRC消息以及封装在所述上行RRC消息外部的PDCP层和适配信息。
  14. 根据权利要求10-13任一项所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述CU发送的下行通用分组无线服务技术隧道协议GTP-U帧，所述下行GTP-U帧包括所述远程UE的下行数据信息、第一指示以及所述中继UE的GTP-U隧道的隧道端点标识，所述下行数据信息包括所述远程UE的下行数据包以及封装在所述下行数据包外部的PDCP层和适配信息，适配信息用于指示所述下行数据包是所述远程UE的下行数据包，第一指示用于指示所述下行数据包外部封装有适配信息；
    所述DU向所述中继UE发送封装了RLC层、MAC层以及PHY层的所述下行数据信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示所述下行数据包外部封装有适配信息。
  15. 根据权利要求10-14任一项所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述中继UE发送的所述远程UE的上行数据信息，所述上行数据信息包括所述远程UE的上行数据包以及封装在所述上行数据包外部的PDCP层、适配信息、RCL层、MAC层以及PHY层，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示所述上行数据包外部封装有适配信息，适配信息用于指示所述上行数据包为所述远程UE的上行数据包；
    所述DU向所述CU发送上行GTP-U帧，所述上行GTP-U帧包括第一指示、所述中继UE的GTP-U隧道的隧道端点标识、所述上行数据包以及封装在所述上行数据包外部的PDCP层和适配信息，第一指示用于指示所述上行数据包外部封装有适配信息。
  16. 根据权利要求10所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述CU发送的用户上下文建立请求消息，所述用户上下文建立请求消息包括所述中继UE的标识、所述远程UE的标识、所述远程UE的承载标识与所述逻辑信道之间的映射关系，所述用户上下文建立请求消息用于请求所述DU建立所述远程UE的上下文；
    所述DU根据所述中继UE的标识、所述远程UE的标识、所述远程UE的承载标识与所述逻辑信道之间的映射关系，生成所述远程UE的RRC配置信息。
  17. 根据权利要求16所述的方法，其特征在于，所述用户上下文建立请求消息还携带第二指示，所述第二指示用于指示所述DU在向所述中继UE发送所述远程UE的下行数据信息或下行RRC信息时，在所述下行数据信息或下行RRC信息中增加适配信息，适配信息用于指示所述下行数据信息或下行RRC信息是所述远程UE的下行数据信息或下行RRC信息。
  18. 根据权利要求16或17所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述CU发送的下行RRC信息传输消息，所述下行RRC信息传输消息包括所述远程UE的下行RRC信息和所述远程UE在CU-DU接口的标识，所述下行RRC信息包括所述远程UE的下行RRC消息和封装在所述下行RRC消息外部的PDCP层；
    所述DU向所述中继UE发送封装了适配信息、RLC层、MAC层以及PHY层的所述下 行RRC信息，PHY层、MAC层或者RLC层中携带第三指示，第三指示用于指示所述下行RRC消息外部封装有适配信息，适配信息用于指示所述下行RRC消息为所述远程UE的下行RRC消息。
  19. 根据权利要求16-18任一项所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述中继UE发送的上行RRC信息，所述上行RRC信息包括所述远程UE的上行RRC消息和依次封装在所述上行RRC消息外部的PDCP层、适配信息、RLC层、MAC层以及PHY层,RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示所述上行RRC消息外部封装有适配信息，适配信息用于指示所述上行RRC消息为所述远程UE的上行RRC消息；
    所述DU根据第三指示读取所述上行RRC信息中的适配信息，以确定所述远程UE的承载标识中用于传输所述上行RRC信息的承载标识和所述远程UE在CU-DU接口的标识；
    所述DU向所述CU发送上行RRC信息传输消息，所述上行RRC信息传输消息包括所述用于传输所述上行RRC信息的承载标识、所述远程UE在CU-DU接口的标识、所述上行RRC消息以及封装在所述上行RRC消息外部的PDCP层。
  20. 根据权利要求16-19任一项所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述CU发送的下行GTP-U帧，所述下行GTP-U帧包括所述远程UE的下行数据信息以及所述远程UE的GTP-U隧道的隧道端点标识，所述下行数据信息包括所述远程UE的下行数据包以及封装在所述下行数据包外部的PDCP层；
    所述DU向所述中继UE发送封装了适配信息、RLC层、MAC层以及PHY层的所述下行数据信息，RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示所述下行数据包外部封装有适配信息，适配信息用于指示所述下行数据包为所述远程UE的下行数据包。
  21. 根据权利要求16-20任一项所述的方法，其特征在于，所述方法还包括：
    所述DU接收所述中继UE发送的上行数据信息，所述上行数据信息包括所述远程UE的上行数据包和依次封装在所述上行数据包外部的PDCP层、适配信息、RLC层、MAC层以及PHY层,RLC层、MAC层或者PHY层中携带第三指示，第三指示用于指示所述上行数据包外部封装有适配信息，适配信息用于指示所述上行数据包为所述远程UE的上行数据包；
    所述DU根据第三指示读取所述上行数据信息中的适配信息，以确定所述远程UE的承载标识中用于传输所述上行数据信息的承载标识，和与所述用于传输所述上行数据信息的承载标识对应的所述远程UE的GTP-U隧道的隧道端点标识；
    所述DU向所述CU发送上行GTP-U帧，所述上行GTP-U帧包括所述用于传输所述上行数据信息的承载标识、所述远程UE的GTP-U隧道的隧道端点标识、所述上行数据包以及封装在所述上行数据包外部的PDCP层。
  22. 一种通信装置，其特征在于，包括存储器和处理器，所述存储器用于存储计算机程序，所述处理器用于从存储器中调用并运行所述计算机程序，使得所述通信装置执行如权利要求1-9任一项所述的通信方法。
  23. 一种计算机存储介质，存储有程序，其特征在于，所述程序用于实现如权利 要求1-9任一项所述的通信方法。
  24. 一种通信装置，其特征在于，包括存储器和处理器，所述存储器用于存储计算机程序，所述处理器用于从存储器中调用并运行所述计算机程序，使得所述通信装置执行如权利要求10-21任一项所述的通信方法。
  25. 一种计算机存储介质，存储有程序，其特征在于，所述程序用于实现如权利要求10-21任一项所述的通信方法。
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