CN113455097A

CN113455097A - Method and device for recovering link failure

Info

Publication number: CN113455097A
Application number: CN201980092501.8A
Authority: CN
Inventors: 王静; 李晨琬; 吴毅凌; 李振宇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-03-29
Filing date: 2019-03-29
Publication date: 2021-09-28
Also published as: WO2020198961A1

Abstract

The embodiment of the application provides a method and equipment for recovering link failure, wherein the method comprises the following steps: the second communication equipment sends a first Radio Resource Control (RRC) connection reestablishment request message to the first communication equipment, wherein the first RRC connection reestablishment request message is used for requesting the second communication equipment and the network equipment to reestablish RRC connection; receiving a first RRC connection reestablishment message sent by first communication equipment; and then, a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of the Signaling Radio Bearer (SRB) are reestablished according to the first RRC connection reestablishment message, and the SRB of the second communication equipment is recovered, so that the RRC connection between the second communication equipment and the network equipment is recovered, namely a control plane of multi-hop communication between the second communication equipment and the network equipment is recovered.

Description

Method and device for recovering link failure

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and a device for recovering a link failure.

Background

In some communication application scenarios, such as an electric power scenario, a problem of insufficient coverage capability of a base station often occurs, in order to extend a coverage, at least one relay device is usually deployed, so that terminals at the edge of the coverage of the base station or which cannot be covered by the base station can communicate with the base station through the relay device, thereby forming a multi-hop communication link. The multi-hop communication technology can improve the coverage area of the base station to a great extent, so that more terminals can communicate with the base station.

In a multi-hop communication network, if one of the relay devices fails in a Radio Link Failure (RLF), the relay device and the node device connected to the relay device cannot communicate with the base station. Therefore, in order to ensure that the relay device and the node devices connected to the relay device communicate with the base station normally, a recovery process of the link failure needs to be performed. However, in the prior art, only the radio link failure recovery between the terminal and the base station in the one-hop communication mode is supported, and the link recovery after the relay device or the terminal device generates the RLF in the multi-hop communication mode is not supported.

Therefore, how to recover the communication with the base station after the RLF occurs in the relay device is an urgent technical problem to be solved by those skilled in the art.

Disclosure of Invention

The application provides a method and equipment for recovering link failure, which can recover communication with a base station after a relay device generates RLF.

In a first aspect, an embodiment of the present application provides a method for recovering a link failure, where the method for recovering the link failure may be implemented by

The method comprises the following steps:

sending a first Radio Resource Control (RRC) connection reestablishment request message to the first communication device, wherein the first RRC connection reestablishment request message is used for requesting the second communication device and the network device to reestablish RRC connection;

receiving a first RRC connection reestablishment message sent by first communication equipment;

and reestablishing a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of the Signaling Radio Bearer (SRB) according to the first RRC connection reestablishment message, and recovering the SRB of the second communication equipment, so that the RRC connection between the second communication equipment and the network equipment is recovered, namely, a control plane of multi-hop communication between the second communication equipment and the network equipment is recovered.

In a possible implementation manner, after reconstructing the packet data convergence protocol PDCP and the radio link control protocol RLC of the signaling radio bearer SRB according to the first RRC connection reestablishment message, the method may further include:

and sending an RRC connection reestablishment completion message to the network equipment so as to inform the network equipment of the completion of the RRC connection reestablishment.

In one possible implementation, the method may further include:

reconstructing RLC of a data radio bearer DRB according to a first RRC connection reconfiguration message sent by first communication equipment; and/or the like, and/or,

and reconstructing PDCP of the DRB according to the second RRC connection reconfiguration message sent by the network equipment to recover the DRB, thereby further recovering the multi-hop communication user plane between the second communication equipment and the network equipment. In addition, by means of link failure recovery between the second communication device and the network device, the situation that a child node device (third communication device) of the second communication device executes a reconstruction process is avoided, and signaling overhead of recovering communication between the child node device of the second communication device and the base station after the second communication device in the multi-hop link generates RLF is reduced.

In a possible implementation manner, after re-establishing the RLC of the data radio bearer DRB according to the first RRC connection reconfiguration message sent by the first communication device, the method may further include:

a first RRC connection reconfiguration complete message is sent to the first communication device.

In a possible implementation manner, after reconstructing the PDCP of the DRB according to the second RRC connection reconfiguration message sent by the network device, the method may further include:

and sending a second RRC connection reconfiguration complete message to the network equipment.

In a possible implementation manner, if the network device is different from the network device that was serviced before the second communication device reestablishes service, the method may further include:

sending first indication information to the third communication equipment; the first indication information is used for indicating the third communication device to initiate an RRC connection reestablishment procedure.

In one possible implementation, the first indication information is carried in RRC signaling, a medium access control element, MAC CE, or physical layer signaling.

In one possible implementation, the first indication information includes at least one of:

the method comprises the steps of identifying a cell, indexing a carrier corresponding to a cell synchronous channel, and a special cell radio network temporary identifier C-RNTI or random access channel RACH resource; wherein the cell is a cell served by the second communication device.

In a possible implementation manner, before sending the first indication information to the third communication device, the method may further include:

receiving a third RRC connection reconfiguration message sent by the network equipment; the third RRC connection reconfiguration message comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device;

and according to the third RRC connection reconfiguration message, establishing or configuring the cell, so that other communication equipment can search the cell and take the second communication equipment as a parent node (namely, access the second communication equipment) to communicate with the network equipment.

In a second aspect, an embodiment of the present application further provides a method for recovering a link failure, where the method for recovering a link failure may include:

receiving a first Radio Resource Control (RRC) connection reestablishment request message sent by second communication equipment, wherein the first RRC connection reestablishment request message is used for requesting the second communication equipment and network equipment to reestablish RRC connection;

a first RRC connection reestablishment message is sent to the second communication device.

In a possible implementation manner, before sending the first RRC connection reestablishment message to the second communication device, the method may further include:

receiving a second RRC connection reestablishment message sent by the network equipment;

and generating a first RRC connection reestablishment message according to the second RRC connection reestablishment message, so that the second communication equipment reestablishes the packet data convergence protocol PDCP and the radio link control protocol RLC of the signaling radio bearer SRB according to the first RRC connection reestablishment message.

and sending a second RRC connection reestablishment request message to the network equipment, wherein the second RRC connection reestablishment request message comprises the identification which is allocated to the second communication equipment by the first communication equipment.

In one possible implementation, the method may further include:

generating a first RRC connection reconfiguration message according to a fourth RRC connection reconfiguration message sent by the network equipment;

and sending the first RRC connection reconfiguration message to the second communication equipment, so that the second communication equipment rebuilds the RLC of the data radio bearer DRB after receiving the first RRC connection reconfiguration message.

In a possible implementation manner, after sending the first RRC connection reconfiguration message to the second communication device, the method may further include:

receiving a first RRC connection reconfiguration completion message sent by second communication equipment;

and sending a fourth RRC connection reconfiguration complete message to the network equipment.

In a third aspect, an embodiment of the present application further provides a method for recovering a link failure, where the method for recovering a link failure may include:

receiving a second Radio Resource Control (RRC) connection reestablishment request message sent by the first communication equipment, wherein the second RRC connection reestablishment request message comprises an identifier distributed to the second communication equipment by the first communication equipment;

and sending a second RRC connection reestablishment message to the first communication device.

In a possible implementation manner, after sending the second RRC connection reestablishment message to the first communication device, the method may further include:

and receiving an RRC connection reestablishment completion message sent by the second communication equipment.

In one possible implementation, the method may further include:

sending a fourth RRC connection reconfiguration message to the first communication device; the fourth RRC connection reconfiguration message is used to instruct the first communications device to reconfigure the bearer according to the fourth RRC connection reconfiguration message;

and sending a second RRC connection reconfiguration message to the second communication device.

In a possible implementation manner, after sending the fourth RRC connection reconfiguration message to the first communication device, the method may further include:

and receiving a fourth RRC connection reconfiguration complete message sent by the first communication equipment.

In a possible implementation manner, after sending the second RRC connection reconfiguration message to the second communication device, the method may further include:

and receiving a second RRC connection reconfiguration complete message sent by the second communication equipment.

In one possible implementation, the method may further include:

sending a third RRC connection reconfiguration message to the second communication device; the third RRC connection reconfiguration message is used for indicating the second communication equipment to establish a cell or configure the cell, and comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device.

In a possible implementation manner, after sending the third RRC connection reconfiguration message to the second communication device, the method may further include:

and receiving a third RRC connection reconfiguration complete message sent by the second communication equipment.

In a fourth aspect, an embodiment of the present application further provides a communication device, where the communication device may include:

a sending unit, configured to send a first RRC connection reestablishment request message to a first communication device, where the first RRC connection reestablishment request message is used to request that an RRC connection be reestablished between a second communication device and a network device;

a receiving unit, configured to receive a first RRC connection reestablishment message sent by a first communication device;

and the processing unit is used for reestablishing a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of the Signaling Radio Bearer (SRB) according to the first RRC connection reestablishment message.

In a possible implementation manner, the sending unit is further configured to send an RRC connection reestablishment complete message to the network device.

In a possible implementation manner, the processing unit is further configured to reconstruct the RLC of the DRB according to the first RRC connection reconfiguration message sent by the first communication device; and/or reconstructing the PDCP of the DRB according to a second RRC connection reconfiguration message sent by the network equipment.

In a possible implementation manner, the sending unit is further configured to send a first RRC connection reconfiguration complete message to the first communication device.

In a possible implementation manner, the sending unit is further configured to send a second RRC connection reconfiguration complete message to the network device.

In a possible implementation manner, if the network device is different from the network device served before the second communication device is reestablished, the sending unit is further configured to send the first indication information to the third communication device; the first indication information is used for indicating the third communication device to initiate an RRC connection reestablishment procedure.

In a possible implementation manner, the receiving unit is further configured to receive a third RRC connection reconfiguration message sent by the network device; the third RRC connection reconfiguration message comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device;

and the processing unit is further configured to establish a cell or configure the cell according to the third RRC connection reconfiguration message.

In a fifth aspect, an embodiment of the present application further provides a communication device, where the communication device may include:

a receiving unit, configured to receive a first radio resource control, RRC, connection reestablishment request message sent by a second communication device, where the first RRC connection reestablishment request message is used to request the second communication device to reestablish an RRC connection with a network device;

a sending unit, configured to send a first RRC connection reestablishment message to the second communication device.

In one possible implementation, the communication device may further include a processing unit;

the receiving unit is further configured to receive a second RRC connection reestablishment message sent by the network device;

and the processing unit is used for generating a first RRC connection reestablishment message according to the second RRC connection reestablishment message.

In a possible implementation manner, the sending unit is configured to send a second RRC connection reestablishment request message to the network device, where the second RRC connection reestablishment request message includes an identifier that is allocated by the first communication device for the second communication device.

In a possible implementation manner, the processing unit is further configured to generate a first RRC connection reconfiguration message according to a fourth RRC connection reconfiguration message sent by the network device;

the sending unit is further configured to send the first RRC connection reconfiguration message to the second communication device.

In a possible implementation manner, the receiving unit is further configured to receive a first RRC connection reconfiguration complete message sent by the second communication device;

the sending unit is further configured to send a fourth RRC connection reconfiguration complete message to the network device.

In a sixth aspect, an embodiment of the present application further provides a communication device, where the communication device may include:

a receiving unit, configured to receive a second RRC connection reestablishment request message sent by a first communication device, where the second RRC connection reestablishment request message includes an identifier allocated by the first communication device to a second communication device;

a sending unit, configured to send a second RRC connection reestablishment message to the first communication device.

In a possible implementation manner, the receiving unit is further configured to receive an RRC connection reestablishment complete message sent by the second communication device.

In a possible implementation manner, the sending unit is further configured to send a fourth RRC connection reconfiguration message to the first communication device; the fourth RRC connection reconfiguration message is used to instruct the first communications device to reconfigure the bearer according to the fourth RRC connection reconfiguration message; and sending a second RRC connection reconfiguration message to the second communication device.

In a possible implementation manner, the receiving unit is further configured to receive a fourth RRC connection reconfiguration complete message sent by the first communication device.

In a possible implementation manner, the receiving unit is further configured to receive a second RRC connection reconfiguration complete message sent by the second communication device.

In a possible implementation manner, the sending unit is further configured to send a third RRC connection reconfiguration message to the second communication device; the third RRC connection reconfiguration message is used for indicating the second communication equipment to establish a cell or configure the cell, and comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device.

In a possible implementation manner, the receiving unit is further configured to receive a third RRC connection reconfiguration complete message sent by the second communication device.

In a seventh aspect, embodiments of the present application further provide a communication device, which may include a processor and a memory, wherein,

the memory is used for storing program instructions;

the processor is configured to read a program instruction in the memory, and execute the method for recovering the link failure in any one of the possible implementations of the first aspect, or execute the method for recovering the link failure in any one of the possible implementations of the second aspect, or execute the method for recovering the link failure in any one of the possible implementations of the third aspect according to the program instruction in the memory.

In an eighth aspect, an embodiment of the present application further provides a computer storage medium, where the computer storage medium includes instructions that, when executed by one or more processors, cause a communication device to perform the method for recovering a link failure in any one of the foregoing possible implementations of the first aspect, or perform the method for recovering a link failure in any one of the foregoing possible implementations of the second aspect, or perform the method for recovering a link failure in any one of the foregoing possible implementations of the third aspect.

In a ninth aspect, an embodiment of the present application further provides a chip, where the chip stores a computer program, and when the computer program is executed by a processor, the method for recovering a link failure in any one of the foregoing possible implementation manners of the first aspect is executed, or the method for recovering a link failure in any one of the foregoing possible implementation manners of the second aspect is executed, or the method for recovering a link failure in any one of the foregoing possible implementation manners of the third aspect is executed.

In a tenth aspect, an embodiment of the present application further provides a communication system, which may include a first communication device, a second communication device, and a network device, where the second communication device is the communication device described in any one of the foregoing possible implementation manners of the fourth aspect, the first communication device is the communication device described in any one of the foregoing possible implementation manners of the fifth aspect, and the network device is the communication device described in any one of the foregoing possible implementation manners of the sixth aspect.

According to the method and the device for recovering the link failure, the second communication device sends a first Radio Resource Control (RRC) connection reestablishment request message to the first communication device, wherein the first RRC connection reestablishment request message is used for requesting the second communication device and the network device to reestablish RRC connection; receiving a first RRC connection reestablishment message sent by first communication equipment; and then, a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of the Signaling Radio Bearer (SRB) are reestablished according to the first RRC connection reestablishment message, and the SRB of the second communication equipment is recovered, so that the RRC connection between the second communication equipment and the network equipment is recovered, namely a control plane of multi-hop communication between the second communication equipment and the network equipment is recovered.

Drawings

Fig. 1 is a schematic view of an application scenario provided in an embodiment of the present application;

fig. 2 is a schematic flowchart of a method for recovering a link failure according to an embodiment of the present application;

fig. 3 is a schematic flowchart of another method for recovering a link failure according to an embodiment of the present application;

fig. 4 is a schematic flowchart of another method for recovering a link failure according to an embodiment of the present application;

fig. 5 is a schematic diagram of a reconstruction failure according to an embodiment of the present application;

fig. 6 is a schematic flow chart of data recovery according to an embodiment of the present application;

fig. 7 is a schematic diagram of a format of a PDCP control PDU according to an embodiment of the present application;

fig. 8 is a schematic diagram of another PDCP control PDU format according to an embodiment of the present application;

fig. 9 is a schematic diagram of a format of another PDCP control PDU according to an embodiment of the present application;

fig. 10 is a schematic diagram of a format of a PDCP control PDU according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 12 is a schematic structural diagram of another communication device provided in an embodiment of the present application;

fig. 13 is a schematic structural diagram of another communication device provided in an embodiment of the present application;

fig. 14 is a schematic structural diagram of a communication device according to an embodiment of the present application.

Detailed Description

The embodiment of the application can be applied to an LTE system, an Enterprise LTE Discrete narrowband Aggregation (LTE-DSA) system, and other communication systems, such as a New Radio (NR) system, a fifth generation (5G) mobile communication system, or other mobile communication systems that may appear in the future.

Some terms in the present application are explained below to facilitate understanding by those skilled in the art. It should be noted that, when the scheme of the embodiment of the present application is applied to a 5G or other mobile communication system that may appear in the future, names of the network device and the terminal may change, but this does not affect the implementation of the scheme of the embodiment of the present application.

Fig. 1 is a schematic view of an application scenario provided in an embodiment of the present application, where the communication system may include a terminal device, three communication devices and a network device, where the three communication devices are a first communication device, a second communication device and an original communication device, and because the coverage capability of the network device is limited, when the terminal communicates with the network device, data transmission may be performed through the second communication device and the original communication device, that is, the second communication device and the original communication device serve as relay devices, so as to implement communication between the terminal device and the network device. For example, during the uplink transmission, the terminal device may transmit data to its parent node device, i.e., the second communication device; the second communication equipment transmits the data to the father node equipment, namely the original communication equipment; and the original communication equipment transmits the data to the network equipment, thereby completing the uplink transmission process of the data. In the downlink transmission process, the network device can transmit data to the original communication device, and the original communication device transmits the data to the child node device, namely the second communication device; and the second communication equipment transmits the data to the terminal equipment, thereby finishing the downlink transmission process of the data. By arranging the second communication equipment and the original communication equipment between the terminal equipment and the network equipment, the coverage area of the network equipment can be improved, so that more terminal equipment can communicate with the network equipment. When the second communication device fails to perform a wireless link or a handover failure, so that a link between the second communication device and the original communication device is interrupted, at this time, the second communication device may access the first communication device, and determine the first communication device as a parent node device of the second communication device, so that the second communication device may implement communication with the network device through the first communication device. In the multi-hop communication mode, a communication device accessed by a communication device may be referred to as a parent node.

The terminal device is also called a terminal or a User Equipment (UE), and is a device that provides voice and/or data connectivity to a user, for example, a handheld device, a vehicle-mounted device, an internet of things device, and the like having a wireless connection function. Common terminal devices include, for example: a mobile phone, a tablet computer, a notebook computer, a handheld computer, a Mobile Internet Device (MID), an electric power communication device, a Customer Premises Equipment (CPE), and a wearable device, where the wearable device includes: smart watches, smart bracelets, pedometers, and the like.

A network device, also called Radio Access Network (RAN) device, is an access device in which a terminal device accesses to the mobile communication system in a wireless manner, and may be a base station NodeB, an evolved node b (eNB), a Transmission and Reception Point (TRP), a next generation base station (next generation NodeB, gNB) in a 5G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system; or may be a module or a unit that performs part of the functions of the base station, for example, a Centralized Unit (CU) or a Distributed Unit (DU). The embodiments of the present application do not limit the specific technologies and the specific device forms adopted by the radio access network device.

A relay device is a device capable of providing data forwarding, for example, an integrated access and backhaul node (IAB node), where the IAB node not only provides data forwarding, but also provides wireless access service and wireless backhaul service for other communication devices. The communication equipment can access the IAB node and carry out multi-hop communication with the network equipment through the IAB node. The relay device may also be a terminal device having a relay function, or a CPE.

It can be understood that, when the second communication device can access the first communication device, the network device accessed by the first communication device may be the same network device as the network device accessed by the original parent node device (i.e., the original communication device) of the second communication device, or may be a different network device from the network device accessed by the original communication device. These two possible scenarios will be described in detail below by the embodiments shown in fig. 2 and 3, respectively.

In the embodiments of the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. In the description of the text of the present application, the character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

In a first possible scenario, a network device accessed by a first communication device and a network device accessed by an original communication device are the same network device, for example, please refer to fig. 2, where fig. 2 is a schematic flow diagram of a method for recovering link failure according to an embodiment of the present application, where the method for recovering link failure may include:

s201, the second communication device sends a first Radio Resource Control (RRC) connection reestablishment request message to the first communication device.

The first RRC connection reestablishment request message is used to request the second communication device and the network device to reestablish the RRC connection.

It is to be understood that, after detecting that RLF occurs in the second communication device, or the handover fails, or the integrity check fails, or the RRC connection reconfiguration fails, the second communication device sends a first RRC connection reestablishment request message to the first communication device to request the second communication device and the network device to reestablish the RRC connection. For example, the first RRC connection reestablishment request message may include a reestablishment reason and identity information of the second communication device; wherein the identity information of the second communication device may include: a short integrity message authentication code (shortMAC-I), a cell radio network temporary Identifier (C-RNTI) used when the second communication device generates RLF, and a Physical Cell Identifier (PCI) of a serving cell when the second communication device generates RLF. For example, the first RRC connection reestablishment request message may be an rrcconnectionrequestablistequest-UR message.

The first communication device and the second communication device may be Relay user equipment (Relay UE), or access backhaul integrated node (IAB node), or other communication devices with Relay function.

The network device may be a base station or an access backhaul integrated base station (IAB Donor).

S202, the first communication device sends a second RRC connection reestablishment request message to the network device.

The second RRC connection reestablishment request message includes an identifier allocated by the first communication device to the second communication device. Illustratively, the identity allocated by the first communication device to the second communication device is a C-RNTI. Illustratively, the second RRC connection reestablishment request message is an rrcconnectionrequestablistenergerequest-IAB message.

After receiving the first RRC connection reestablishment request message, the first communication device allocates an identifier to the second communication device, and sends the identifier to the network device by carrying the identifier in the second RRC connection reestablishment request message, so as to request the network device that the second communication device needs to reestablish the RRC connection. For example, the second RRC connection reestablishment request message may further include a reestablishment reason and identity information of the second communication device; likewise, the identity information of the second communication device may include: shortMAC-I, C-RNTI used when the second communication equipment generates RLF, and PCI of a service cell when the second communication equipment generates RLF.

After assigning the identity to the second communication device, the first communication device may send a second RRC connection reestablishment request message including the identity of the second communication device to the network device, so that the network device performs the following S203 after receiving the second RRC connection reestablishment request message:

s203, the network device sends a second RRC connection reestablishment message to the first communication device.

For example, the second RRC connection reestablishment message may include a security parameter, such as a next hop chain count (nextHopChainingCount), where the security parameter is used for the second communication device to update an air interface key, so that the second communication device may perform encryption according to the updated air interface key.

For example, the second RRC connection reestablishment message may include a C-RNTI of the second communication device to indicate that the second RRC connection reestablishment message is for reestablishing an RRC connection between the second communication device and the network device. For example, the second RRC connection reestablishment message may be an rrcconnectionreessabeliment-IAB message.

S204, the first communication device sends a first RRC connection reestablishment message to the second communication device.

For example, the first RRC connection reestablishment message may include security parameters, such as a next hop chain count, and optionally, the first RRC connection reestablishment message may further include radio resource configuration information, which may be one or more of the following: RLC configuration information, logical channel configuration information, medium access control address (MAC) configuration information, physical layer (PHY) configuration information, and the like. For example, the first RRC connection reestablishment message may be an RRCConnectionReestablishment-UR message.

After receiving a second RRC connection reestablishment message sent by the network device, the first communication device generates a corresponding first RRC connection reestablishment message according to the second RRC connection reestablishment message, and sends the first RRC connection reestablishment message to the second communication device through an interface between the first communication device and the second communication device.

S205, the second communication device reestablishes a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of the Signaling Radio Bearer (SRB) according to the first RRC connection reestablishment message.

After receiving the first RRC connection reestablishment message sent by the first communication device, the second communication device reestablishes a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of a Signaling Radio Bearer (SRB), performs radio resource configuration according to the received radio resource configuration information, thereby recovering the SRB of the second communication device, and updates a corresponding air interface key using the security parameter carried in the first RRC connection reestablishment message.

Optionally, after reconstructing the packet data convergence protocol PDCP and the radio link control protocol RLC of the signaling radio bearer SRB according to the first RRC connection reestablishment message, the second communication device may further send an RRC connection reestablishment complete message to the network device, so as to notify the network device that the RRC connection reestablishment is complete.

Therefore, in this embodiment of the present application, the second communication device sends the first RRC connection reestablishment request message to the first communication device, and the first communication device sends the second RRC connection reestablishment request message to the network device, so as to request the network device that the second communication device needs to reestablish RRC connection, and receives the first RRC connection reestablishment message sent by the first communication device and generated according to the second RRC connection reestablishment message, and then reestablishes the packet data convergence protocol PDCP and the radio link control protocol RLC of the signaling radio bearer SRB according to the first RRC connection reestablishment message, so as to recover the SRB of the second communication device, thereby recovering the RRC connection between the second communication device and the network device, that is, recovering the control plane of the multi-hop communication between the second communication device and the network device.

It is understood that the PDCP and RLC of the SRB may be re-established by S201-S205 in the embodiment shown in fig. 2, so as to recover the SRB, and thus recover the multi-hop communication control plane between the second communication device and the network device. Based on the embodiment shown in fig. 2, further, PDCP and RLC of a Data Radio Bearer (DRB) may be re-established through following S301-S306 to recover the DRB, that is, recover a multi-hop communication user plane between the second communication device and the network device. For example, please refer to fig. 3, where fig. 3 is a schematic flow chart of another method for recovering a link failure according to an embodiment of the present application, where the method for recovering a link failure may further include:

s301, the network device sends a fourth RRC connection reconfiguration message to the first communication device.

And the fourth RRC connection reconfiguration message is used for indicating the first communication equipment to establish or reconfigure the bearer according to the fourth RRC connection reconfiguration message. For example, the fourth RRC connection reconfiguration message may include at least one of: a C-RNTI of the second network device, quality of service (QoS) information of the second network device, a DRB ID.

For example, the fourth RRC connection reconfiguration message may be an RRCConnectionReconfiguration-IAB message or a radiobearesettuppequest-IAB message.

For example, after determining that the RRC connection reestablishment of the second communication device is completed, the network device may send a fourth RRC connection reconfiguration message to the first communication device, so that the first communication device performs the following S302:

s302, the first communication device sends a first RRC connection reconfiguration message to the second communication device.

Wherein the first RRC connection reconfiguration message comprises at least one of: DRB ID, logical channel ID, RLC configuration information, logical channel configuration information, MAC configuration information, PHY configuration information, etc. of the second communication device.

Illustratively, the first RRC connection reconfiguration message is an RRCConnectionReconfiguration-UR message.

For example, after receiving the fourth RRC connection reconfiguration message, the first communication device may generate a corresponding first RRC connection reconfiguration message according to the fourth RRC connection reconfiguration message, and send the first RRC connection reconfiguration message to the second communication device through an interface between the first communication device and the second communication device.

S303, the second communication device rebuilds the RLC of the data radio bearer DRB after receiving the first RRC connection reconfiguration message.

And after receiving the first RRC connection reconfiguration message sent by the first communication equipment, the second communication equipment reconstructs the RLC of the data DRB. Optionally, if the first RRC connection reconfiguration message includes radio resource configuration information, performing radio resource configuration according to the radio resource configuration information. Optionally, after the second communication device reconstructs the RLC of the DRB according to the first RRC connection reconfiguration message, the second communication device may further send a first RRC connection reconfiguration complete message to the first communication device, so as to notify the first communication device that the RRC connection reconfiguration process is completed. Correspondingly, the first communication device may also send a fourth RRC connection reconfiguration complete message to the network device after receiving the first RRC connection reconfiguration complete message. For example, the fourth RRC connection reconfiguration complete message may carry the C-RNTI allocated by the first communication device for the second communication device. For example, the fourth RRC connection reconfiguration complete message may be an rrcconnectionreconfiguration complete-IAB or a radiobearesetuprpesponse-IAB message.

S304, the second communication device rebuilds the PDCP of the DRB.

Illustratively, the network device sends a second RRC connection reconfiguration message to the second communication device. Optionally, the second RRC connection reconfiguration message may also include radio resource configuration information, for example, PDCP configuration information. And after receiving the second RRC connection reconfiguration message, the second communication equipment rebuilds the PDCP of the DRB, and if the second RRC connection reconfiguration message comprises the radio resource configuration information, the second communication equipment performs radio resource configuration according to the radio resource configuration information, so as to recover the DRB of the second communication equipment. Optionally, after the second communication device recovers the DRB, the second communication device may further send an RRC connection reconfiguration complete message to the network device, so as to notify the network device that the RRC connection reconfiguration is complete and the DRB is recovered.

For example, the second communication device re-establishes PDCP of the DRB after receiving the first RRC connection reconfiguration message sent by the first communication device.

It should be understood that the present application does not limit the order of steps S303 and S304, that is, S303 may be executed first and then S304 is executed, or S304 may be executed first and then S303 is executed, and of course, S303 and S304 may also be executed simultaneously, which may be specifically set according to actual needs.

As can be seen, the PDCP and RLC of the DRB may be re-established by S301-S304 in the embodiment shown in fig. 3 to recover the DRB, so as to further recover the multi-hop communication user plane between the second communication device and the network device. In addition, by means of link failure recovery between the second communication device and the network device, the situation that a child node device (third communication device) of the second communication device executes a reconstruction process is avoided, and signaling overhead of recovering communication between the child node device of the second communication device and the base station after the second communication device in the multi-hop link generates RLF is reduced.

It should be noted that, in the embodiment shown in fig. 2 or fig. 3, if the network device determines that the parent node of the second communication device changes or determines that the second communication device is reestablished or switched to another network device, the network device may further send an RRC connection release message to an original parent node device (original communication device) of the second communication device, where the RRC connection release message is used to instruct the original communication device to release the stored context information and related radio resource configuration information of the second communication device. For example, the RRC connection release message may carry a C-RNTI allocated by the original communication device for the second communication device, and is used to instruct the original communication device to release the stored context information and related radio resource configuration information of the second communication device. Correspondingly, after the original communication device receives the RRC connection release message, the original communication device releases the context information and the related radio resource configuration information of the second communication device. Illustratively, the RRC connection Release message is an RRCConnectionRelease-IAB message.

The above-mentioned embodiments shown in fig. 2 and fig. 3 describe in detail how to implement, in one possible scenario, the recovery of the link failure when the network device accessed by the second communication device when the second communication device generates the RLF and the network device corresponding to the second communication device request to reestablish the RRC connection are the same network device. For example, referring to fig. 4, the method for recovering the link failure may include:

on the basis of the embodiment shown in fig. 2, different from the embodiment shown in fig. 2, after receiving the second RRC connection reestablishment request message sent by the first communication device, the network device (the network device to which the second communication device requests to reestablish the RRC connection) needs to communicate with the original network device of the second communication device (i.e., the network device accessed by the second communication device when the second communication device has RLF) before sending the second RRC connection reestablishment message to the first communication device in S203, so as to check reestablishment information of the second communication device and determine whether to reject the reestablishment request of the second communication device. For example, the network device may authenticate the identity of the second communication device through the identity information of the second communication device, or the original network device may retrieve the context of the second communication device and send the context to the network device, where the identity of the second communication device is authenticated by the network device according to the identity information of the second communication device, where the identity information of the second communication device includes shortMAC-I, a C-RNTI used when the second communication device generates RLF, and a PCI of a serving cell when the second communication device generates RLF, so that the validity of the second communication device is determined.

It should be understood that the above-mentioned S201-S205, S301-S304 are also applicable to the link failure recovery after the terminal device in the multi-hop communication mode has RLF.

In addition, the embodiment shown in fig. 3 is different in that, after S304 the second communication device reconstructs the PDCP of the DRB according to the second RRC connection reconfiguration message sent by the network device, the following S401-S402 may be further included, for example, please refer to fig. 4, where fig. 4 is a flowchart of a further method for recovering a link failure according to the embodiment of the present application, and the method for recovering a link failure may further include:

s401, the network device sends a third RRC connection reconfiguration message to the second communication device.

The third RRC connection reconfiguration message is used to instruct the second communications device to establish a cell or configure a cell. For example, the third RRC connection reconfiguration message may include one or more of: the method comprises the following steps that a cell identifier, a carrier index corresponding to a cell synchronous channel, a cell radio network temporary identifier C-RNTI set, random access channel RACH resources and downlink control channel resources are obtained; the cell is served by the second communication device, and the C-RNTI set is used for the second communication device to distribute the C-RNTI to the sub-node device accessed to the second communication device. For example, the cell may be a relay cell or an access backhaul integrated IAB cell. The child node device of the second communication device refers to a communication device that accesses the second communication device in a multi-hop communication mode.

Illustratively, the third RRC connection reconfiguration message is an RRCConnectionReconfiguration-IAB message.

S402, the second communication device establishes the cell or configures the cell according to the third RRC connection reconfiguration message.

After receiving the third RRC connection reconfiguration message, the second communication device may establish or configure a cell according to the third RRC connection reconfiguration message, so that other communication devices may search for the cell and communicate with the network device using the second communication device as a parent node. Wherein the cell is a cell served by the second communication device. For example, the cell may be a relay cell or an access backhaul integrated IAB cell.

Optionally, after the second communication device establishes or configures the cell according to the third RRC connection reconfiguration message, the second communication device may further send a third RRC connection reconfiguration complete message to the network device, so as to notify the network device that the RRC connection reconfiguration process is completed. Illustratively, the third RRC connection reconfiguration complete message is an rrcconnectionreconfiguration complete-IAB message.

It should be noted that after the link failure of the second communication device is recovered, the second communication device further needs to instruct the child node device to initiate an RRC connection reestablishment procedure, and may send the first indication information to the third communication device.

The first indication information is used for indicating the third communication device to initiate an RRC connection reestablishment procedure. Optionally, the first indication information includes at least one of a cell identifier, a carrier index corresponding to a cell synchronization channel, a dedicated cell radio network temporary identifier C-RNTI, or a random access channel RACH resource. Wherein the cell is a cell served by the second communication device. For example, the cell may be a relay cell or an access backhaul integrated IAB cell.

In detail, the first indication information may include only any one of the cell identifier, the carrier index corresponding to the cell synchronization channel, the dedicated cell radio network temporary identifier C-RNTI, or the random access channel RACH resource, or may include any two of the cell identifier, the carrier index corresponding to the cell synchronization channel, the dedicated cell radio network temporary identifier C-RNTI, or the random access channel RACH resource, or may include any three of the cell identifier, the carrier index corresponding to the cell synchronization channel, the dedicated cell radio network temporary identifier C-RNTI, or the random access channel RACH resource, or may include four of the cell identifier, the carrier index corresponding to the cell synchronization channel, the dedicated cell radio network temporary identifier C-RNTI, and the random access channel RACH resource, or may be specifically set according to actual needs, here, the embodiments of the present application are not particularly limited.

Optionally, when the second communication device sends the first indication information to the third communication device, the first indication information may be carried in an RRC signaling, a media access control element MAC CE, or a physical layer signaling, and may be specifically set according to an actual need, which is not specifically limited in the embodiment of the present application. For example, the first indication information may be carried in an RRCConnectionReconfiguration-UR message or an RRCConnectionRelease-UR message.

It should be appreciated that as another implementation of instructing the third communication device to initiate the RRC connection re-establishment procedure, the second communication device may implicitly instruct the third communication device to initiate the RRC connection re-establishment procedure, e.g., the second communication device stops providing communication services to the third communication device, thereby triggering the third communication device to detect the RLF and initiate the RRC connection re-establishment procedure.

Optionally, the original network device sends an RRC connection release-IAB message to the fourth communication device.

Wherein, the RRC connection release-IAB message is used to instruct the fourth communication device to release the context information and the radio resource configuration information of the second communication device; and the second communication equipment reestablishes the cell served by the fourth communication equipment. In this embodiment, the fourth communication device is the original communication device.

It can be seen that, with the embodiment shown in fig. 4, the communication between the second communication device and the network device can also be resumed, and unlike the embodiment shown in fig. 3, the network device accessed when the second communication device generates RLF is different from the network device corresponding to the request of reestablishing RRC connection.

It should be noted that the embodiments shown in fig. 2 to fig. 4 describe in detail how to implement the recovery of the link failure when the network device accessed by the second communication device when the RLF occurs is the same network device as the network device corresponding to the request to reestablish the RRC connection, and how to implement the recovery of the link failure when the network device accessed by the second communication device when the RLF occurs is different from the network device corresponding to the request to reestablish the RRC connection. In the two possible scenarios, the second communication device is successfully reestablished, and conversely, if the second communication device initiates an RRC connection reestablishment process in the process of link recovery, but the reestablishment fails (rejected by the network device or no suitable parent node is found), at this time, the second communication device may explicitly or implicitly instruct a child node device (i.e., a third communication device) thereof to trigger the third communication device to initiate the RRC connection reestablishment process, so that the third communication device finds a new parent node device as a relay device to communicate with the network device, for example, please refer to fig. 5, where fig. 5 is a schematic diagram of a reestablishment failure provided in the embodiment of the present application.

In addition, for the network device, if the network device does not receive the data sent by the second communication device within the first preset time period, it indicates that the second communication device has an RLF failure or the second communication device has no service for a long time, and at this time, the network device may release the context information and the radio resource configuration information of the second communication device. The first preset duration may be set according to actual needs, and the embodiment of the present application is not particularly limited herein.

For example, the first preset duration may be implemented by a timer T1, the timer T1 may be maintained by the network device, and if the timer T1 maintained by the network device is time out, the network device releases the context information and the related configuration information of the second communication device and initiates a route update and bearer reconfiguration process. For the timer T1, which is maintained by the network device and is a UE specific timer (related to the service type), when receiving an uplink packet sent by a corresponding UE or relay device, the timer T1 starts/restarts, starts timing, and if the timer T1 is out of time and no uplink packet sent by the corresponding UE or relay device is received, the network device releases the context information and the radio resource configuration information of the corresponding UE or relay device.

Further, for the second communication device, the second communication device does not receive the data sent by the third communication device within the second preset time period, which indicates that the third communication device has an RLF failure or the third communication device has no service for a long time, and at this time, the second communication device may release the context information and the radio resource configuration information of the third communication device. The second preset duration may be set according to actual needs, and the embodiment of the present application is not particularly limited herein.

For example, the second preset duration may be implemented by a timer T2, the timer T2 may be maintained by the second communication device, and if the timer T2 maintained by the second communication device is time out, the second communication device releases the context information and the related configuration information of the third communication device, and initiates a route update and bearer reconfiguration process. For the timer T2, which is maintained by the second communication device and configured by the network device, and is a UE specific timer (related to the service type), when receiving the uplink data packet sent by the corresponding child node device, the timer T2 starts/restarts, starts timing, and if the timer T2 times out and no uplink data packet sent by the corresponding child node device is received, the second communication device releases the context information and the radio resource configuration information of the corresponding child node device.

For the third communication device, the third communication device does not receive the data sent by the corresponding child node within a third preset time period, which indicates that the child node of the third communication device has an RLF failure or the child node of the third communication device has no service for a long time, and at this time, the third communication device may release the context information and the radio resource configuration information of the corresponding child node. The third preset time period may be set according to actual needs, and the embodiment of the present application is not particularly limited herein. The child node device of the third communication device refers to a communication device that accesses the third communication device in a multi-hop communication mode.

For example, the third preset duration may be implemented by a timer T3, the timer T3 may be maintained by the third communication device, and if the timer T3 maintained by the third communication device is time out, the third communication device releases the context information and the related configuration information of the corresponding child node device, and initiates a route update and bearer reconfiguration process. For the timer T3, which is maintained by the third communication device and configured by the network device, and is a UE specific timer (related to the service type), when receiving an uplink data packet sent by the corresponding child node device, the timer T3 starts/restarts, starts timing, and if the timer T3 is overtime and no uplink data packet sent by the corresponding child node device is received, the third communication device releases the context information and the radio resource configuration information of the corresponding child node device; or the third communication device triggers itself to leave the connected state.

Based on the embodiments shown in fig. 3 or fig. 4, the connection reestablishment of the second communication device and the reconfiguration process after the connection reestablishment can be implemented. In the reconfiguration process of the second communication device, the RLC of the DRB is required to be reconstructed according to the first RRC connection reconfiguration message, and then the PDCP of the DRB is reconstructed according to the second RRC connection reconfiguration message; or reconstructing RLC and PDCP of the data radio bearer DRB according to the first RRC connection reconfiguration message. In the RLC re-establishment process, buffered data of the RLC (including data of the second communication device and the child node devices of the second communication device) is cleared, so that data of the second communication device and the child node devices of the second communication device are lost. When recovering the data lost in the RLC re-establishment process, the data lost in the uplink transmission process may be recovered, and the data lost in the downlink transmission process may also be recovered. For example, please refer to fig. 6, where fig. 6 is a schematic flow chart of data recovery provided in an embodiment of the present application, and the data recovery method may include:

s601, the network equipment sends the uplink PDCP receiving state information to the second communication equipment or the subnode equipment thereof.

Wherein the uplink PDCP receiving status information may include: a first missing uplink PDCP SDU or a Sequence Number (SN) of the first missing uplink PDCP PDU. Optionally, the uplink PDCP receiving status information may further include a bitmap indicating whether each PDCP SDU is successfully received from a next PDCP SDU of a first missing PDCP Service Data Unit (SDU). Optionally, the uplink PDCP receiving status information may further include a bitmap indicating whether each PDCP PDU is successfully received from a PDCP PDU (protocol data unit) next to a first missing PDCP PDU. The child node of the second communication device refers to a communication device accessing the second communication device in a multi-hop communication mode.

For example, when the network device sends the uplink PDCP receipt status information to the second communication device or the sub-node device thereof, the uplink PDCP receipt status information may be carried in a PDCP control PDU and sent to the second communication device or the sub-node device thereof, or may be carried in an RRC message and sent to the second communication device or the sub-node device thereof. For example, when the uplink PDCP reception status information may be carried in a PDCP control PDU and sent to the second communication device or a child node device thereof, please refer to fig. 7, where fig. 7 is a schematic format diagram of a PDCP control PDU provided in this embodiment of the present application. Optionally, in the format of the PDCP control PDU shown in fig. 7, the PDU type field may take a value of 000 or 010 or 011. Wherein, the value of the First Missing SDU (FMS) field is the first missing uplink PDCP SDU SN or the first missing uplink PDCP PDU SN. R is a reserved field. The Bitmap field is optional. D/C (data/control) indicates whether the PDCP PDU is a data PDU or a control PDU. For example, fig. 8 is a schematic diagram of another PDCP control PDU format provided in this embodiment. Wherein SR Type is a status report Type field for indicating the Type of the status report. Different values correspond to different types and to different receiving operations. For example, the SR Type value is 0, which indicates that the status report is used for retransmitting the PDCP PDU, and the operation of retransmitting the PDCP PDU is performed after receiving the status report; and when the SR Type value is 1, indicating that the status report is used for retransmitting the PDCP SDU, and executing corresponding operation of retransmitting the PDCP SDU after receiving the status report. For example, fig. 9 is a schematic diagram of a format of another PDCP control PDU provided in the embodiment of the present application. For example, when the SR Type value is 01 or 00, it indicates that the status report is used for retransmitting the PDCP PDU, and after receiving the status report, performs a corresponding operation of retransmitting the PDCP PDU; and when the SR Type value is 10 or 01, the status report is used for retransmitting the PDCP SDU, and the corresponding operation of retransmitting the PDCP SDU is executed after the status report is received.

S602, the second communication device or the sub-node device thereof receives the uplink PDCP receiving state information and executes retransmission.

Illustratively, the second communication device or a child node device thereof performs a retransmission operation prior to re-establishing PDCP. When the second communication device or the child node device thereof executes the retransmission operation, it may start retransmission from the first missing PDCP SDU indicated by the uplink PDCP reception status information, or transmit all PDCP SDUs that already have PDCP SNs; or, starting retransmission from the first lost PDCP SDU indicated by the uplink PDCP receiving state information, or transmitting all PDCP SDUs with PDCP SNs except the PDCP SDU which is indicated by the bitmap and is successfully received; alternatively, retransmission or transmission is started from a PDCP SDU having a smaller corresponding COUNT value among the first missing PDCP SDU indicated by the uplink PDCP reception status information and the first unsuccessfully transmitted PDCP SDU indicated to the PDCP layer by the RLC layer.

For example, the second communication device or its child node device performs a retransmission operation after receiving the uplink PDCP reception status information. When the second communication device or the child node device thereof performs the retransmission operation, it may start retransmission from the first missing PDCP PDU indicated by the uplink PDCP reception status information, or transmit all buffered PDCP PDUs; or, starting retransmission from the first lost PDCP PDU indicated by the uplink PDCP receiving state information, or transmitting all buffered PDCP PDUs except the PDCP PDU which is indicated by the bitmap and is successfully received; or, starting retransmission or transmission from one PDCP PDU with a smaller corresponding COUNT value among the first missing PDCP PDU indicated by the uplink PDCP reception status information and the first unsuccessfully transmitted PDCP PDU indicated to the PDCP layer by the RLC layer. Optionally, if the SR Type field of the PDCP control PDU corresponding to the uplink PDCP reception status information indicates that the PDCP PDU retransmission operation is performed, for example, the value of the SR Type field is 1, 10, or 01.

For example, the second communication device or its child node device performs a retransmission operation after receiving the uplink PDCP reception status information. When the second communication device or the child node device thereof executes the retransmission operation, it may start retransmission from the first missing PDCP SDU indicated by the uplink PDCP reception status information, or transmit all PDCP SDUs that already have PDCP SNs; or, starting retransmission from the first lost PDCP SDU indicated by the uplink PDCP receiving state information, or transmitting all PDCP SDUs with PDCP SNs except the PDCP SDU which is indicated by the bitmap and is successfully received; or, starting retransmission or transmission from the first missing PDCP SDU indicated by the uplink PDCP reception status information and the PDCP SDU with the COUNT value earlier than the corresponding COUNT value among the first unsuccessfully transmitted PDCP SDUs indicated by the RLC layer to the PDCP layer. Optionally, if the SR Type field of the PDCP control PDU corresponding to the uplink PDCP reception status information indicates that the PDCP SDU retransmission operation is performed, for example, the value of the SR Type field is 0, 01, or 00.

It can be seen that, in the embodiment of the present application, data lost in the uplink transmission process can be recovered through the above S601 and S602.

S603, the second communication device or the sub-node device thereof generates the downlink PDCP receiving state information.

Wherein, the downlink PDCP receiving status information may include: the SN of the first missing downlink PDCP SDU or the SN of the first missing downlink PDCP PDU. Optionally, the downlink PDCP reception status information may further include a bitmap indicating whether each PDCP SDU was successfully received from the next PDCP SDU of the first missing PDCP SDU. Optionally, the uplink PDCP receiving status information may further include a bitmap indicating whether each PDCP PDU is successfully received from a PDCP PDU (protocol data unit) next to a first missing PDCP PDU.

For example, the second communication device or its child node device may generate the downlink PDCP receipt status information before the second communication device or its child node device re-establishes PDCP and/or when the second communication device or its child node device is configured by RRC signaling to send the downlink PDCP receipt status information.

For example, when the second communication device receives the polling information, the polling information is used to request the second communication device or its child node device to send the downlink PDCP receiving status information. The polling information may be a PDCP control PDU, or a field of RRC signaling or PDCP data PDU. For example, when the polling information is a PDCP control PDU, the format of the corresponding PDCP control PDU may be as shown in fig. 10, and fig. 10 is a schematic format diagram of a PDCP control PDU provided in this embodiment of the present application. Optionally, in the format of the PDCP control PDU shown in fig. 10, the value of the PDU type field may be 010 or 111.

S604, the second communication device or the sub-node device thereof sends the downlink PDCP receiving state information to the network device.

And after receiving the polling information, the second communication equipment or the child node equipment thereof sends downlink PDCP receiving state information.

For example, after receiving the polling information sent by the network device, the second communication device or the child node device thereof sends downlink PDCP receiving status information to the network device.

S605, the network equipment executes retransmission operation according to the downlink PDCP receiving state information.

For example, when the network device performs the retransmission operation, it may start to retransmit or transmit all PDCP SDUs that already have PDCP SNs from the first missing PDCP SDU indicated by the downlink PDCP reception status information; or, starting to retransmit or transmit all the PDCP SDUs with the PDCP SN from the first lost PDCP SDU indicated by the downlink PDCP receiving state information except the PDCP SDU which is indicated by the bitmap and is successfully received; alternatively, retransmission or transmission is started from the first missing PDCP SDU indicated by the downlink PDCP reception status information and the earlier PDCP SDU from among the first unsuccessfully transmitted PDCP SDUs indicated by the RLC layer to the PDCP layer.

For example, when the network device performs a retransmission operation, it may start to retransmit or transmit all PDCP PDUs from the first missing PDCP PDU indicated by the downlink PDCP reception status information; or, starting to retransmit or transmit all PDCP PDUs from the first lost PDCP PDU indicated by the downlink PDCP receiving state information except the PDCP PDU which is indicated by the bitmap and is successfully received; or, starting retransmission or transmission from the first missing PDCP SDU indicated by the downlink PDCP reception status information and the PDCP PDU with the smaller corresponding COUNT value among the first unsuccessfully transmitted PDCP PDUs indicated by the RLC layer to the PDCP layer.

It can be seen that, in the embodiment of the present application, the data lost in the downlink transmission process can be recovered through the above S603-S605. It should be noted that there is no sequence between the above S601-S602 and S603-S605, and the above S601-S602 may be executed first, and then the above S603-S605 may be executed; or S603-S605 can be executed first, and then S601-S602 can be executed; of course, the above-mentioned S601-S602 and S603-S605 may also be executed simultaneously, and here, the embodiment of the present application is only described by taking the example of executing the above-mentioned S601-S602 first and then executing the S603-S605, but the embodiment of the present application is not limited thereto.

It is to be understood that the above-described S601-S605 is applicable not only to the child node of the second communication device but also to other lower nodes of the second communication device. The subordinate nodes of the second communication device include child nodes of the second communication device, child nodes of the second communication device, and so on. The child node of the second communication device is a communication device which accesses the child node of the second communication device in a multi-hop communication mode.

It can be understood that the above S601-S605 are not limited to data recovery after RLF occurs in the communication device in the multi-hop network, and may also be applied to data recovery when the communication device in the multi-hop network is switched, which is not limited in this application.

It can be understood that the link failure recovery method provided in the present application is not limited to the communication device in which RLF occurs in the multi-hop network, but may also be applied to the communication device in which RRC connection reconfiguration fails, the communication device in which integrity check fails, or the communication device in which handover fails, and the present application does not limit this.

Fig. 11 is a schematic structural diagram of a communication device 110 according to an embodiment of the present application, for example, please refer to fig. 11, where the communication device 110 may include:

a sending unit 1101, configured to send a first radio resource control, RRC, connection reestablishment request message to a first communication device, where the first RRC connection reestablishment request message is used to request that an RRC connection between a second communication device and a network device is reestablished.

A receiving unit 1102, configured to receive a first RRC connection reestablishment message sent by a first communication device.

The processing unit 1103 is configured to reestablish a packet data convergence protocol PDCP and a radio link control protocol RLC of the signaling radio bearer SRB according to the first RRC connection reestablishment message.

Optionally, the sending unit 1101 is further configured to send an RRC connection reestablishment complete message to the network device.

Optionally, the processing unit 1103 is further configured to reestablish the RLC of the DRB according to the first RRC connection reconfiguration message sent by the first communication device; and/or reconstructing the PDCP of the DRB according to a second RRC connection reconfiguration message sent by the network equipment.

Optionally, the sending unit 1101 is further configured to send a first RRC connection reconfiguration complete message to the first communication device.

Optionally, the sending unit 1101 is further configured to send a second RRC connection reconfiguration complete message to the network device.

Optionally, if the network device is different from the network device served before the second communication device is reestablished, the sending unit 1101 is further configured to send the first indication information to the third communication device; the first indication information is used for indicating the third communication device to initiate an RRC connection reestablishment procedure.

Optionally, the first indication information is carried in RRC signaling, MAC CE, or physical layer signaling.

Optionally, the first indication information includes at least one of:

Optionally, the receiving unit 1102 is further configured to receive a third RRC connection reconfiguration message sent by the network device; the third RRC connection reconfiguration message comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device;

the processing unit 1103 is further configured to establish a cell or configure the cell according to the third RRC connection reconfiguration message.

The communication device 110 shown in the embodiment of the present application may execute the method for recovering the link failure on the second communication device side in the embodiments shown in fig. 2 to fig. 6, and the implementation principle and the beneficial effect of the method are similar to those of the method for recovering the link failure on the second communication device side, and details are not repeated here.

Fig. 12 is a schematic structural diagram of another communication device 120 according to an embodiment of the present application, for example, please refer to fig. 12, where the communication device 120 may include:

a receiving unit 1201, configured to receive a first RRC connection reestablishment request message sent by a second communication device, where the first RRC connection reestablishment request message is used to request the second communication device to reestablish an RRC connection with a network device.

A sending unit 1202, configured to send a first RRC connection reestablishment message to the second communication device.

Optionally, the communication device 120 may further include a processing unit 1203.

The receiving unit 1201 is further configured to receive a second RRC connection reestablishment message sent by the network device.

The processing unit 1203 is configured to generate a first RRC connection reestablishment message according to the second RRC connection reestablishment message.

Optionally, the sending unit 1202 is configured to send a second RRC connection reestablishment request message to the network device, where the second RRC connection reestablishment request message includes an identifier that the first communication device is configured to be allocated to the second communication device.

Optionally, the processing unit 1203 is further configured to generate a first RRC connection reconfiguration message according to a fourth RRC connection reconfiguration message sent by the network device.

The sending unit 1202 is further configured to send the first RRC connection reconfiguration message to the second communication device.

Optionally, the receiving unit 1201 is further configured to receive a first RRC connection reconfiguration complete message sent by the second communication device.

The sending unit 1202 is further configured to send a fourth RRC connection reconfiguration complete message to the network device.

The communication device 120 shown in the embodiment of the present application may execute the method for recovering the link failure on the first communication device side in the embodiments shown in fig. 2 to fig. 6, and the implementation principle and the beneficial effect of the method for recovering the link failure on the first communication device side are similar to those of the method for recovering the link failure on the first communication device side, and details are not repeated here.

Fig. 13 is a schematic structural diagram of another communication device 130 provided in an embodiment of the present application, for example, please refer to fig. 13, where the communication device 130 may include:

a receiving unit 1301, configured to receive a second RRC connection reestablishment request message sent by the first communication apparatus, where the second RRC connection reestablishment request message includes an identifier allocated by the first communication apparatus to the second communication apparatus.

A sending unit 1302, configured to send a second RRC connection reestablishment message to the first communication device.

Optionally, the receiving unit 1301 is further configured to receive an RRC connection reestablishment complete message sent by the second communication device.

Optionally, the sending unit 1302 is further configured to send a fourth RRC connection reconfiguration message to the first communication device; the fourth RRC connection reconfiguration message is used to instruct the first communications device to reconfigure the bearer according to the fourth RRC connection reconfiguration message; and sending a second RRC connection reconfiguration message to the second communication device.

Optionally, the receiving unit 1301 is further configured to receive a fourth RRC connection reconfiguration complete message sent by the first communication device.

Optionally, the receiving unit 1301 is further configured to receive a second RRC connection reconfiguration complete message sent by the second communication device.

Optionally, the sending unit 1302 is further configured to send a third RRC connection reconfiguration message to the second communication device; the third RRC connection reconfiguration message is used for indicating the second communication equipment to establish a cell or configure the cell, and comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device.

Optionally, the receiving unit 1301 is further configured to receive a third RRC connection reconfiguration complete message sent by the second communication device.

The communication device 130 shown in the embodiment of the present application may execute the method for recovering the link failure on the network device side in the embodiments shown in fig. 2 to fig. 6, and the implementation principle and the beneficial effect of the method for recovering the link failure on the network device side are similar to those of the method for recovering the link failure on the network device side, and details are not described here again.

Fig. 14 is a schematic structural diagram of a communication device 140 according to an embodiment of the present application, and for example, referring to fig. 14, the communication device 140 may include a processor 1401 and a memory 1402, wherein,

memory 1402 is used to store program instructions;

the processor 1401 is configured to read the program instruction in the memory 1402, and execute the method for recovering the link failure on the second communication device side in the embodiment shown in fig. 2 to 6 according to the program instruction in the memory 1402, or execute the method for recovering the link failure on the first communication device side in the embodiment shown in fig. 2 to 6, or execute the method for recovering the link failure on the network device side in the embodiment shown in fig. 2 to 6, which is similar to the implementation principle and the beneficial effect of the method for recovering the link failure, and therefore, details are not described here.

An embodiment of the present application further provides a communication system, which may include a first communication device, a second communication device, and a network device, where the first communication device is configured to execute the method for recovering the link failure on the first communication device side in the embodiment shown in fig. 2 to 6, the second communication device is configured to execute the method for recovering the link failure on the second communication device side in the embodiment shown in fig. 2 to 6, and the network device is configured to execute the method for recovering the link failure on the network device side in the embodiment shown in fig. 2 to 6, and an implementation principle and beneficial effects of the method for recovering the link failure are similar to an implementation principle and beneficial effects of the method for recovering the link failure, and are not described herein again.

An embodiment of the present application further provides a computer storage medium, which includes instructions, and when the instructions are executed by one or more processors, the communication device executes a method for recovering a link failure on a second communication device side in the embodiment shown in fig. 2 to 6, or executes a method for recovering a link failure on a first communication device side in the embodiment shown in fig. 2 to 6, or executes a method for recovering a link failure on a network device side in the embodiment shown in fig. 2 to 6, where an implementation principle and beneficial effects of the method for recovering a link failure are similar to an implementation principle and beneficial effects of the method for recovering a link failure, and details are not described here.

An embodiment of the present application further provides a chip, where a computer program is stored on the chip, and when the computer program is executed by a processor, the method for recovering a link failure on a second communication device side in the embodiment shown in fig. 2 to 6 is executed, or the method for recovering a link failure on a first communication device side in the embodiment shown in fig. 2 to 6 is executed, or the method for recovering a link failure on a network device side in the embodiment shown in fig. 2 to 6 is executed, where an implementation principle and beneficial effects of the method for recovering a link failure are similar to those of the method for recovering a link failure, and details are not described here.

The processor in the above embodiments may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, or discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules may be located in a Random Access Memory (RAM), a flash memory, a read-only memory (ROM), a programmable ROM, an electrically erasable programmable memory, a register, or other storage media that are well known in the art. The storage medium is located in a memory, and a processor reads instructions in the memory and combines hardware thereof to complete the steps of the method.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.

Claims

A method for recovering link failure, comprising:

sending a first Radio Resource Control (RRC) connection reestablishment request message to the first communication device, wherein the first RRC connection reestablishment request message is used for requesting the second communication device and the network device to reestablish RRC connection;

receiving a first RRC connection reestablishment message sent by the first communication equipment;

and reconstructing a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of a Signaling Radio Bearer (SRB) according to the first RRC connection reestablishment message.
The method of claim 1, wherein after reestablishing the packet data convergence protocol PDCP and radio link control protocol RLC of the signaling radio bearer SRB according to the first RRC connection reestablishment message, the method further comprises:

and sending an RRC connection reestablishment completion message to the network equipment.
The method according to claim 1 or 2, characterized in that the method further comprises:

reconstructing RLC of a Data Radio Bearer (DRB) according to a first RRC connection reconfiguration message sent by the first communication equipment; and/or the like, and/or,

and reconstructing PDCP of the DRB according to the second RRC connection reconfiguration message sent by the network equipment.
The method of any of claims 1-3, wherein if the network device is different from the network device that was serviced before the second communication device reestablished service, the method further comprises:

sending first indication information to the third communication equipment; the first indication information is used for indicating the third communication device to initiate an RRC connection reestablishment process; wherein the first indication information is carried in RRC signaling, media access control element (MAC CE) or physical layer signaling.
The method of claim 4,

the first indication information includes at least one of:

the method comprises the steps of identifying a cell, indexing a carrier corresponding to a cell synchronous channel, and a special cell radio network temporary identifier C-RNTI or random access channel RACH resource; wherein the cell is a cell served by the second communication device.
The method according to claim 4 or 5, wherein before sending the first indication information to the third communication device, further comprising:

receiving a third RRC connection reconfiguration message sent by the network equipment; the third RRC connection reconfiguration message comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device;

and establishing the cell or configuring the cell according to the third RRC connection reconfiguration message.
A method for recovering link failure, comprising:

receiving a first Radio Resource Control (RRC) connection reestablishment request message sent by second communication equipment, wherein the first RRC connection reestablishment request message is used for requesting the second communication equipment and network equipment to reestablish RRC connection;

and sending a first RRC connection reestablishment message to the second communication equipment.
The method of claim 7, wherein before sending the first RRC connection reestablishment message to the second communication device, further comprising:

receiving a second RRC connection reestablishment message sent by the network equipment;

and generating the first RRC connection reestablishment message according to the second RRC connection reestablishment message.
The method according to claim 7 or 8, wherein before sending the first RRC connection reestablishment message to the second communication device, further comprising:

and sending a second RRC connection reestablishment request message to the network equipment, wherein the second RRC connection reestablishment request message comprises an identifier which is allocated to the second communication equipment by the first communication equipment.
The method according to any one of claims 7-9, further comprising:

generating a first RRC connection reconfiguration message according to a fourth RRC connection reconfiguration message sent by the network equipment;

sending the first RRC connection reconfiguration message to the second communication device.
A method for recovering link failure, comprising:

receiving a second Radio Resource Control (RRC) connection reestablishment request message sent by a first communication device, wherein the second RRC connection reestablishment request message comprises an identifier distributed to the second communication device by the first communication device;

sending a second RRC connection reestablishment message to the first communication device.
The method of claim 11, wherein after sending the second RRC connection reestablishment message to the first communication device, further comprising:

and receiving an RRC connection reestablishment completion message sent by the second communication equipment.
The method according to claim 11 or 12, characterized in that the method further comprises:

sending a fourth RRC connection reconfiguration message to the first communication device; the fourth RRC connection reconfiguration message is used to instruct the first communication device to reconfigure a bearer according to the fourth RRC connection reconfiguration message;

sending a second RRC connection reconfiguration message to the second communication device.
The method according to any one of claims 11-13, further comprising:

sending a third RRC connection reconfiguration message to the second communication device; the third RRC connection reconfiguration message is used to instruct the second communications device to establish a cell or configure a cell; the third RRC connection reconfiguration message comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device.
A communication device, comprising:

a sending unit, configured to send a first RRC connection reestablishment request message to a first communication device, where the first RRC connection reestablishment request message is used to request that an RRC connection be reestablished between a second communication device and a network device;

a receiving unit, configured to receive a first RRC connection reestablishment message sent by the first communication device;

and the processing unit is used for reestablishing a Packet Data Convergence Protocol (PDCP) and a radio link control protocol (RLC) of the Signaling Radio Bearer (SRB) according to the first RRC connection reestablishment message.
The apparatus of claim 15,

the sending unit is further configured to send an RRC connection reestablishment complete message to the network device.
The apparatus according to claim 15 or 16,

the processing unit is further configured to reestablish the RLC of the DRB according to the first RRC connection reconfiguration message sent by the first communication device; and/or reconstructing the PDCP of the DRB according to the second RRC connection reconfiguration message sent by the network equipment.
The device according to any of claims 15-17, wherein the sending unit is further configured to send first indication information to a third communication device if the network device is different from the network device that was served before the second communication device reestablishment; the first indication information is used for indicating the third communication device to initiate an RRC connection reestablishment process; wherein the first indication information is carried in RRC signaling, media access control element (MAC CE) or physical layer signaling.
The apparatus of claim 18,

the first indication information includes at least one of:

the method comprises the steps of identifying a cell, indexing a carrier corresponding to a cell synchronous channel, and a special cell radio network temporary identifier C-RNTI or random access channel RACH resource; wherein the cell is a cell served by the second communication device.
The apparatus according to claim 18 or 19,

the receiving unit is further configured to receive a third RRC connection reconfiguration message sent by the network device; the third RRC connection reconfiguration message comprises a cell identifier, a carrier index corresponding to a cell synchronization channel, a special cell radio network temporary identifier C-RNTI and a random access channel RACH resource; wherein the cell is a cell served by the second communication device;

the processing unit is further configured to establish the cell or configure the cell according to the third RRC connection reconfiguration message.
A communication device, comprising:

a receiving unit, configured to receive a first radio resource control, RRC, connection reestablishment request message sent by a second communication device, where the first RRC connection reestablishment request message is used to request the second communication device to reestablish an RRC connection with a network device;

a sending unit, configured to send a first RRC connection reestablishment message to the second communication device.
The device of claim 21, wherein the communication device further comprises a processing unit;

the receiving unit is further configured to receive a second RRC connection reestablishment message sent by the network device;

the processing unit is configured to generate the first RRC connection reestablishment message according to the second RRC connection reestablishment message.
The apparatus of claim 21 or 22,

the sending unit is configured to send a second RRC connection reestablishment request message to the network device, where the second RRC connection reestablishment request message includes an identifier that is allocated by the first communication device to the second communication device.
The apparatus of claim 22,

the processing unit is further configured to generate a first RRC connection reconfiguration message according to a fourth RRC connection reconfiguration message sent by the network device;

the sending unit is further configured to send the first RRC connection reconfiguration message to the second communication device.
A communication device, comprising:

a receiving unit, configured to receive a second RRC connection reestablishment request message sent by a first communication device, where the second RRC connection reestablishment request message includes an identifier allocated by the first communication device to a second communication device;

a sending unit, configured to send a second RRC connection reestablishment message to the first communication device.
The apparatus of claim 25,

the receiving unit is further configured to receive an RRC connection reestablishment complete message sent by the second communication device.
The apparatus of claim 25 or 26,

the sending unit is further configured to send a fourth RRC connection reconfiguration message to the first communication device; the fourth RRC connection reconfiguration message is used to instruct the first communication device to reconfigure a bearer according to the fourth RRC connection reconfiguration message; and sending a second RRC connection reconfiguration message to the second communication device.
The apparatus according to any one of claims 25 to 27,

the sending unit is further configured to send a third RRC connection reconfiguration message to the second communication device; the third RRC connection reconfiguration message is used to instruct the second communications device to establish or configure a cell, where the third RRC connection reconfiguration message includes a cell identifier, a carrier index corresponding to a cell synchronization channel, a dedicated cell radio network temporary identifier C-RNTI, and a random access channel RACH resource; wherein the cell is a cell served by the second communication device.
A communication device comprising a processor and a memory, wherein,

the memory is to store program instructions;

the processor is configured to read the program instructions in the memory, and execute the method for recovering a link failure according to any one of claims 1 to 6, or execute the method for recovering a link failure according to any one of claims 7 to 10, or execute the method for recovering a link failure according to any one of claims 11 to 14 according to the program instructions in the memory.
A computer storage medium comprising instructions that, when executed by one or more processors, cause a communication device to perform the method for recovering from a link failure of any one of claims 1-6, or to perform the method for recovering from a link failure of any one of claims 7-10, or to perform the method for recovering from a link failure of any one of claims 11-14.