Communication method, communication device and communication system

Abstract

The present application provides a communication method, a communication device, and a communication system, the method comprising: a terminal device determines that a radio resource control (RRC) connection with a first cell has failed, wherein the first cell belongs to a first base station; the terminal device sends a first message to a second base station, the first message being used to request re-establishment of the RRC connection, the first message carrying first indication information and first auxiliary indication information, the first indication information including a physical cell identifier (PCI) of the first cell, and the first auxiliary indication information including information for determining the first base station. The communication method provided in the present application can control the number of candidate base stations determined by a target base station, thereby saving signaling overhead and improving communication efficiency.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a communication method, a communication device, and a communication system. Background Art

[0002] After a terminal device establishes a radio resource control (RRC) connection with the network and enters the RRC connected state (RRC_CONNECTED), if radio link failure, handover failure, integrity protection check failure, RRC reconfiguration failure, etc. occur, the RRC re-establishment process may be triggered. This process aims to re-establish the RRC connection, including the resumption of signaling radio bearer 1 (SRB1) operations, to restore service continuity.

[0003] For example, the terminal device may send an RRC re-establishment request message to the target base station, which carries the physical cell identifier (PCI) of the source cell corresponding to the terminal device. If the target base station determines that it does not have the context of the terminal device, it may determine at least one candidate base station based on the PCI (the at least one candidate base station includes the source base station of the terminal device, but the target base station does not know which specific one it is), and the target base station may send a restore terminal device context request message to the at least one candidate base station to request the context of the terminal device.

[0004] In the fifth generation (5G) communication system, base stations will be deployed more densely, and each base station may have more cells. According to the existing RRC re-establishment mechanism, when the target base station requests the context of the terminal device, the number of determined candidate base stations may surge. As a result, the target base station will send terminal device context recovery request messages to a large number of candidate base stations and receive a large number of terminal device context recovery failure messages sent by non-source base stations, which may cause waste of signaling overhead and reduce communication efficiency. Summary of the Invention

[0005] The present application provides a communication method, a communication device, and a communication system, which can control the number of candidate base stations determined by a target base station, thereby saving signaling overhead and improving communication efficiency.

[0006] In a first aspect, a communication method is provided. The method may be executed by a terminal device, or may be executed by a chip or circuit configured in the terminal device, and this application does not limit this.

[0007] In some possible implementations, the method may include: determining that the radio resource control (RRC) connection with the first cell has failed, wherein the first cell belongs to the first base station; sending a first message to the second base station, the first message being used to request re-establishment of the RRC connection, the first message carrying first indication information and first auxiliary indication information, the first indication information including the physical cell identifier (PCI) of the first cell, and the first auxiliary indication information including information used to determine the first base station.

[0008] In this embodiment of the present application, in addition to first indication information indicating the PCI of the first cell, the first message also includes first auxiliary indication information. The first auxiliary indication information includes information used to identify the first base station, that is, the first auxiliary indication information can provide auxiliary indication for the first base station. The content indicated by the first auxiliary indication information should be different from the content indicated by the first indication information. In other words, the first auxiliary indication information indicates information other than the PCI of the first cell, or in other words, the first auxiliary indication information includes information other than the PCI of the first cell.

[0009] After receiving the first message, the second base station may determine at least one candidate base station according to the first indication information and the first auxiliary indication information in the first message, where the at least one candidate base station includes the first base station.

[0010] According to the communication method provided in the embodiment of the present application, the second base station can determine the candidate base station based on the first indication information and the first auxiliary indication information. Since the PCI of the cell is a local identifier, compared with determining the candidate base station only based on the PCI of the first cell, the present application uses more message content to determine the candidate base station, thereby making the range of the candidate base stations clearer, and can control the number of candidate base stations determined by the second base station, reduce the number of determined candidate base stations, and reduce the number of terminal device context recovery request messages sent by the second base station and reduce the number of terminal device context recovery failure messages sent by the candidate base station, thereby saving signaling overhead and improving communication efficiency.

[0011] Optionally, the first message may be an RRC re-establishment request message.

[0012] Optionally, the first message may also be an RRC reestablishment request message 1 (RRC ReestablishmentRequest 1).

[0013] Optionally, the first message may carry a cell radio network temporary identifier (c-RNTI) and a short message authentication code for Integrity (short MAC-I) of the terminal device.

[0014] In combination with the first aspect, in certain implementations of the first aspect, the first auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; cell global identifier CGI information of the first cell; and identification information of the first base station.

[0015] Optionally, the first auxiliary indication information may indicate any one of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0016] Optionally, the first auxiliary indication information may indicate two or three of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0017] In conjunction with the first aspect, in certain implementations of the first aspect, the first auxiliary indication information occupies one bit, and the one bit is a reserved bit in an existing RRC re-establishment request message. The first auxiliary indication information indicates attribute information of at least one of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station. This allows the format of the existing RRC re-establishment request message to remain unchanged, resulting in greater versatility.

[0018] Optionally, the attribute information may be parity information of the frequency points.

[0019] Optionally, the first auxiliary indication information may occupy multiple bits.

[0020] Optionally, the first auxiliary indication information may indicate parity information of two or three of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0021] With reference to the first aspect, in certain implementations of the first aspect, the first auxiliary indication information includes indication information of the frequency information of the first cell, including: the first auxiliary indication information includes all or part of the frequency information of the first cell. In embodiments of the present application, candidate base stations are jointly determined by the PCI of the first cell and the frequency information of the first cell, so that the number of determined candidate base stations is significantly reduced, and the number of terminal device context restore request messages and terminal device context restore failure messages sent can be reduced, thereby saving signaling overhead and improving communication efficiency.

[0022] Optionally, the first auxiliary indication information indicates the frequency information of the first cell. The first auxiliary indication information may include an index value of the frequency of the first cell. In this case, the second base station can determine the frequency of the first cell based on the index value. Through the above configuration, the first auxiliary indication information can contain less content, which is conducive to saving signaling overhead.

[0023] Optionally, the terminal device may determine the index value corresponding to the frequency of the first cell based on a frequency-index list in the frequency information broadcast in the system information blocks 4 (SIB4) sent by the second base station.

[0024] In conjunction with the first aspect, in certain implementations of the first aspect, the first auxiliary indication information includes indication information of the CGI information of the first cell, including: the first auxiliary indication information includes all or part of the CGI information of the first cell. In embodiments of the present application, candidate base stations are jointly determined by the PCI of the first cell and the CGI information of the first cell, so that the number of determined candidate base stations is significantly reduced, and the number of terminal device context restore request messages and terminal device context restore failure messages sent can be reduced, thereby saving signaling overhead and improving communication efficiency.

[0025] With reference to the first aspect, in certain implementations of the first aspect, the first auxiliary indication information includes indication information of the identification information of the first base station, including: the first auxiliary indication information includes all or part of the identification information of the first base station. In an embodiment of the present application, candidate base stations are jointly determined by the PCI of the first cell and the identification information of the first base station, so that the number of determined candidate base stations is significantly reduced, and the number of terminal device context recovery request messages and terminal device context recovery failure messages sent can be reduced, thereby saving signaling overhead and improving communication efficiency.

[0026] In combination with the first aspect, in certain implementations of the first aspect, before sending the first message to the second base station, the method may also include: receiving third indication information sent by the second base station, the third indication information being used to indicate whether the second base station supports receiving the first auxiliary indication information; sending the first message to the second base station, including: sending the first message to the second base station when it is determined that the second base station supports receiving the first auxiliary indication information.

[0027] On the second aspect, a communication method is provided. The method can be executed by an access network device (such as a gNB), or can be executed by a chip or circuit configured in the access network device. This application does not limit this.

[0028] In some possible implementations, the method may include: receiving a first message sent by a terminal device, the first message is used to request re-establishing an RRC connection, the first message carries first indication information and first auxiliary indication information, the first indication information includes a physical cell identifier PCI of a first cell, the first auxiliary indication information includes information used to determine a first base station, wherein the first cell is a cell in which the RRC connection of the terminal device fails, and the first cell belongs to the first base station; determining at least one candidate base station based on the first indication information and the first auxiliary indication information, the at least one candidate base station including the first base station.

[0029] In combination with the second aspect, in certain implementations of the second aspect, the first auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; cell global identifier CGI information of the first cell; and identification information of the first base station.

[0030] In combination with the second aspect, in certain implementations of the second aspect, the first auxiliary indication information occupies one bit, and one bit is a reserved bit, and the first auxiliary indication information indicates attribute information of at least one of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0031] In combination with the second aspect, in some implementations of the second aspect, the first auxiliary indication information includes indication information of the frequency information of the first cell, including: the first auxiliary indication information includes all or part of the frequency information of the first cell.

[0032] In combination with the second aspect, in some implementations of the second aspect, the first auxiliary indication information includes indication information of the CGI information of the first cell, including: the first auxiliary indication information includes all or part of the CGI information of the first cell.

[0033] In combination with the second aspect, in some implementations of the second aspect, the first auxiliary indication information includes indication information of the identification information of the first base station, including: the first auxiliary indication information includes all or part of the identification information of the first base station.

[0034] In combination with the second aspect, in some implementations of the second aspect, before receiving the first message from the terminal device, the method may further include: sending third indication information to the terminal device, the third indication information being used to indicate support for receiving the first auxiliary indication information.

[0035] In combination with the second aspect, in certain implementations of the second aspect, the method may further include: determining a second message based on the first indication information and the first auxiliary indication information, the second message being used to request the context of the terminal device; and the second base station sending the second message to the candidate base station.

[0036] In combination with the second aspect, in certain implementations of the second aspect, the second message carries second indication information and second auxiliary indication information, the second indication information includes the PCI of the first cell, and the second auxiliary indication information includes information used to determine the first cell.

[0037] There may be multiple cells with PCI #1 under the same candidate base station. Compared with determining whether the context of the terminal device exists only based on the PCI of the first cell, the embodiment of the present application can simultaneously determine whether the context of the terminal device exists based on the second indication information (the PCI of the first cell) and the second auxiliary indication information (information other than the PCI of the first cell). At this time, some cells can be excluded according to the second auxiliary indication information (for example, some cells are excluded according to the parity information of the frequency point), without using the algorithm corresponding to each cell in the multiple cells to calculate multiple shortMAC-Is in sequence, thereby improving the computing speed of the candidate base station and improving communication efficiency.

[0038] Optionally, when the first auxiliary indication information only includes identification information of the first base station, the second message may include second indication information, the second indication information includes the PCI of the first cell, and the second indication information may be the same as the first indication information.

[0039] Optionally, when the first auxiliary indication information includes the frequency information of the first cell and / or the CGI information of the first cell, the second message may include, in addition to the second indication information, second auxiliary indication information, and the second auxiliary indication information includes information used to determine the first cell.

[0040] The content indicated by the second auxiliary indication information should be different from the content indicated by the second indication information, that is, the second auxiliary indication information indicates information other than the PCI of the first cell, or in other words, the second auxiliary indication information includes information other than the PCI of the first cell.

[0041] The second auxiliary indication information can be determined based on the first indication information and the first auxiliary indication information. The content included in the second auxiliary indication information can be the same as or different from the content included in the first auxiliary indication information, and this application does not limit this.

[0042] For example, the first auxiliary indication information may include the frequency information of the first cell, in which case the second auxiliary indication information may include the frequency information of the first cell; or, the second base station may determine the CGI of the first cell based on the PCI and frequency information of the first cell, in which case the second auxiliary indication information may also include the CGI information of the first cell.

[0043] For another example, the first auxiliary indication information may include the CGI information of the first cell, in which case the second auxiliary indication information may include the CGI information of the first cell; alternatively, the second base station may determine the frequency of the first cell based on the PCI and CGI information of the first cell, in which case the second auxiliary indication information may also include the frequency information of the first cell.

[0044] That is, the second auxiliary indication information may indicate at least one of the frequency information of the first cell and the CGI information of the first cell.

[0045] For example, the second auxiliary indication information may include all or part of the frequency information of the first cell.

[0046] For another example, the second auxiliary indication information may include all or part of the CGI information of the first cell.

[0047] For another example, the second auxiliary indication information may include attribute information of the frequency information of the first cell and / or attribute information of the CGI information of the first cell.

[0048] Optionally, the attribute information may be parity information.

[0049] In the embodiment of the present application, after determining the second message, the terminal device sends the second message to the candidate base station. The candidate base station can determine whether there is a context of the terminal device based on the second message.

[0050] Optionally, the second message may be a terminal device context restoration request message.

[0051] Optionally, the second message may also be a retrieve UE context request message 1 (retrieve UE context request 1).

[0052] Optionally, the second message also carries information such as the c-RNTI, shortMAC-I and identifier of the target cell of the terminal device.

[0053] Optionally, the second message includes second indication information, and the candidate base station then determines whether the context of the terminal device exists based on the second indication information.

[0054] In combination with the second aspect, in certain implementations of the second aspect, the first auxiliary indication information includes frequency information of the first cell, and the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0055] In combination with the second aspect, in certain implementations of the second aspect, the first auxiliary indication information includes CGI information of the first cell, and the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0056] On the third aspect, a communication method is provided. The method can be executed by an access network device (such as a gNB), or can be executed by a chip or circuit configured in the access network device. This application does not limit this.

[0057] In some possible implementations, the method may include: receiving a second message sent by a second base station, the second message is used to request the context of the terminal device, the second message carries second indication information and second auxiliary indication information, the second indication information includes the physical cell identifier PCI of the first cell, the second auxiliary indication information includes information used to determine the first cell, and the first cell is the cell where the RRC connection of the terminal device fails; determining whether the context of the terminal device exists based on the second indication information and the second auxiliary indication information.

[0058] In combination with the third aspect, in certain implementations of the third aspect, the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0059] For example, the second auxiliary indication information may include all or part of the frequency information of the first cell.

[0060] For another example, the second auxiliary indication information may include all or part of the CGI information of the first cell.

[0061] In a fourth aspect, a communication device is provided. In some possible implementations, the communication device may include: a processing unit, used to determine that the RRC connection between the communication device and a first cell has failed, wherein the first cell belongs to a first base station; a transceiver unit, used to send a first message to a second base station, the first message being used to request re-establishment of the RRC connection, the first message carrying first indication information and first auxiliary indication information, the first indication information including a physical cell identifier PCI of the first cell, and the first auxiliary indication information including information used to determine the first base station.

[0062] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; cell global identifier CGI information of the first cell; and identification information of the first base station.

[0063] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first auxiliary indication information occupies one bit, and the one bit is a reserved bit, and the first auxiliary indication information indicates attribute information of at least one of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0064] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first auxiliary indication information includes indication information of the frequency information of the first cell, including: the first auxiliary indication information includes all or part of the frequency information of the first cell.

[0065] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first auxiliary indication information includes indication information of the CGI information of the first cell, including: the first auxiliary indication information includes all or part of the CGI information of the first cell.

[0066] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first auxiliary indication information includes indication information of the identification information of the first base station, including: the first auxiliary indication information includes all or part of the identification information of the first base station.

[0067] In combination with the fourth aspect, in certain implementations of the fourth aspect, before the transceiver unit sends the first message to the second base station, the transceiver unit is also used to: receive third indication information sent by the second base station, the third indication information being used to indicate whether the second base station supports receiving the first auxiliary indication information; the transceiver unit is specifically used to: when it is determined that the second base station supports receiving the first auxiliary indication information, the transceiver unit sends the first message to the second base station.

[0068] In a fifth aspect, a communication device is provided. In some possible implementation methods, the communication device may include: a transceiver unit, used to receive a first message sent by a terminal device, the first message is used to request to re-establish an RRC connection, the first message carries first indication information and first auxiliary indication information, the first indication information includes a physical cell identifier PCI of the first cell, and the first auxiliary indication information includes information used to determine a first base station, wherein the first cell is a cell in which the RRC connection of the terminal device fails, and the first cell belongs to the first base station; a processing unit, used to determine at least one candidate base station based on the first indication information and the first auxiliary indication information, and the at least one candidate base station includes the first base station.

[0069] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; cell global identifier CGI information of the first cell; and identification information of the first base station.

[0070] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first auxiliary indication information occupies one bit, and the one bit is a reserved bit, and the first auxiliary indication information indicates attribute information of at least one of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0071] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first auxiliary indication information includes indication information of the frequency information of the first cell, including: the first auxiliary indication information includes all or part of the frequency information of the first cell.

[0072] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first auxiliary indication information includes indication information of the CGI information of the first cell, including: the first auxiliary indication information includes all or part of the CGI information of the first cell.

[0073] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first auxiliary indication information includes indication information of the identification information of the first base station, including: the first auxiliary indication information includes all or part of the identification information of the first base station.

[0074] In combination with the fifth aspect, in certain implementations of the fifth aspect, before the transceiver unit receives the first message sent by the terminal device, the transceiver unit is also used to: send third indication information to the terminal device, and the third indication information is used to indicate that the second base station supports receiving the first auxiliary indication information.

[0075] In combination with the fifth aspect, in certain implementations of the fifth aspect, the processing unit is further used to: determine a second message based on the first indication information and the first auxiliary indication information, the second message being used to request the context of the terminal device; the transceiver unit is further used to: send the second message to the candidate base station.

[0076] In combination with the fifth aspect, in certain implementations of the fifth aspect, the second message carries second indication information and second auxiliary indication information, the second indication information includes the PCI of the first cell, and the second auxiliary indication information includes information used to determine the first cell.

[0077] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first auxiliary indication information includes frequency information of the first cell, and the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0078] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first auxiliary indication information includes CGI information of the first cell, and the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0079] In the sixth aspect, a communication device is provided. In some possible implementation methods, the communication device may include: a transceiver unit, used to receive a second message sent by a second base station, the second message is used to request the context of the terminal device, the second message carries second indication information and second auxiliary indication information, the second indication information includes the physical cell identifier PCI of the first cell, and the second auxiliary indication information includes information used to determine the first cell, and the first cell is the cell where the RRC connection of the terminal device fails; a processing unit, used to determine whether there is a context of the terminal device based on the second indication information and the second auxiliary indication information.

[0080] In combination with the sixth aspect, in certain implementations of the sixth aspect, the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0081] In a seventh aspect, a communication device is provided, which may be a terminal device or a chip within a terminal device. The device may include a processing unit and a transceiver unit. When the device is a terminal device, the processing unit may be a processor, and the transceiver unit may be a transceiver; the terminal device may further include a storage unit, which may be a memory; the storage unit is used to store instructions, and the processing unit executes the instructions stored in the storage unit to cause the terminal device to perform the method of the first aspect. When the device is a chip within a terminal device, the processing unit may be a processor, and the transceiver unit may be an input / output interface, a pin, or a circuit; the processing unit executes the instructions stored in the storage unit to cause the terminal device to perform the method of the first aspect or the second aspect; the storage unit may be a storage unit within the chip (e.g., a register, a cache, etc.), or a storage unit within the terminal device located outside the chip (e.g., a read-only memory, a random access memory, etc.).

[0082] In an eighth aspect, a communication device is provided. The device may be an access network device or a chip within the access network device. The device may include a processing unit and a transceiver unit. When the device is an access network device, the processing unit may be a processor, and the transceiver unit may be a transceiver. The access network device may further include a storage unit, which may be a memory. The storage unit is configured to store instructions, and the processing unit executes the instructions stored in the storage unit to cause the access network device to perform the method of the second aspect. When the device is a chip within a network device, the processing unit may be a processor, and the transceiver unit may be an input / output interface, pin, or circuit. The processing unit executes the instructions stored in the storage unit to cause the network device to perform the method of the second aspect. The storage unit may be a storage unit within the chip (e.g., a register, cache, etc.), or a storage unit within the access network device located outside the chip (e.g., a read-only memory, a random access memory, etc.).

[0083] In a ninth aspect, a communication device is provided. The device may be an access network device or a chip within the access network device. The device may include a processing unit and a transceiver unit. When the device is an access network device, the processing unit may be a processor, and the transceiver unit may be a transceiver. The access network device may further include a storage unit, which may be a memory. The storage unit is configured to store instructions, and the processing unit executes the instructions stored in the storage unit to cause the access network device to perform the method of the third aspect. When the device is a chip within a network device, the processing unit may be a processor, and the transceiver unit may be an input / output interface, pin, or circuit. The processing unit executes the instructions stored in the storage unit to cause the network device to perform the method of the third aspect. The storage unit may be a storage unit within the chip (e.g., a register, cache, etc.), or a storage unit within the access network device located external to the chip (e.g., a read-only memory, a random access memory, etc.).

[0084] In a tenth aspect, a communication device is provided, comprising at least one processor, wherein the at least one processor is used to couple with a memory, read and execute instructions in the memory, so as to implement any one of the methods in the first aspect, the second aspect or the third aspect.

[0085] Optionally, the communication device further includes the memory.

[0086] In an eleventh aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in the first, second or third aspect above.

[0087] It should be noted that the above-mentioned computer program code can be stored in whole or in part on the first storage medium, wherein the first storage medium can be packaged together with the processor or separately from the processor, and this application does not make any specific restrictions on this.

[0088] In the twelfth aspect, a computer-readable medium is provided, wherein the computer-readable medium stores a program code, and when the computer program code is run on a computer, the computer executes the method in the first aspect, the second aspect or the third aspect above.

[0089] In the thirteenth aspect, a chip system is provided, comprising a processor for calling and running a computer program from a memory, so that a communication device equipped with the chip system executes the method in the first, second or third aspect above.

[0090] In the fourteenth aspect, a communication system is provided, which includes at least one of the communication device provided in the fourth aspect, the communication device provided in the fifth aspect, and the communication device provided in the sixth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 It is a schematic diagram of a communication system provided in an embodiment of the present application.

[0092] Figure 2 It is a schematic interaction diagram of the RRC re-establishment process of the terminal device.

[0093] Figure 3 This is a schematic flowchart of an example of a communication method provided in an embodiment of the present application.

[0094] Figure 4 This is a schematic block diagram of an example of a communication device provided in an embodiment of the present application.

[0095] Figure 5 It is a structural diagram of the terminal device provided in an embodiment of the present application.

[0096] Figure 6 This is another schematic block diagram of a communication device provided in an embodiment of the present application.

[0097] Figure 7 This is another schematic block diagram of a communication device provided in an embodiment of the present application.

[0098] Figure 8 It is a structural diagram of the access network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0099] The technical solution in this application will be described below with reference to the accompanying drawings.

[0100] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, fifth generation (5G) communication system or new radio (NR) communication system and new wireless communication systems evolved in the future.

[0101] To facilitate understanding of the embodiments of the present application, first Figure 1 The communication system shown in FIG. 1 is used as an example to describe in detail a communication system applicable to an embodiment of the present application. Figure 1 1 is a schematic diagram of a communication system 100 provided in an embodiment of the present application.

[0102] like Figure 1 As shown, the communication system 100 may include at least two access network devices (e.g., base station 110 and base station 120) and a terminal device (e.g., terminal device 130). The terminal device is connected to the access network device in a wireless manner, and the access network device is connected to the core network device in a wireless or wired manner. The core network device is connected to the core network device in a wireless or wired manner. Figure 1 Not shown in the figure, it should be understood that the core network equipment and the access network equipment can be independent and different physical devices, or the functions of the core network equipment and the logical functions of the access network equipment can be integrated into the same physical device, or part of the functions of the core network equipment and part of the functions of the access network equipment can be integrated into one physical device.

[0103] Terminal devices can be fixed in location or mobile. Figure 1 This is just a schematic diagram. The communication system may also include other network devices, such as wireless relay devices and wireless backhaul devices. Figure 1 The embodiment of the present application does not limit the number of core network devices, access network devices, and terminal devices included in the communication system 100.

[0104] Access network equipment may include devices within the access network that communicate with wireless terminals over the air interface through one or more sectors. The access network system can convert received air frames to and from Internet Protocol (IP) packets, acting as a router between the wireless terminals and the rest of the access network, which may include an IP network. The wireless access network system also coordinates the management of air interface attributes. It should be understood that the access network equipment includes but is not limited to: evolved Node B (eNB), radio network controller (RNC), node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (for example, Home evolved NodeB, or HomeNode B, HNB), baseband unit (BBU), access point (AP) in wireless fidelity (WIFI) system, wireless relay node, wireless backhaul node, transmission point (TRP or transmission point, TP), etc., and can also be a gNB in 5G, such as NR, system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or it can also be a network node constituting a gNB or transmission point, such as a baseband unit (BBU), or a distributed unit (DU), etc.

[0105] In some deployments, a gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some gNB functions, while the DU implements some gNB functions. For example, the CU implements radio resource control (RRC) and packet data convergence protocol (PDCP) layer functions, while the DU implements radio link control (RLC), media access control (MAC), and physical (PHY) layer functions. Because RRC layer information ultimately becomes PHY layer information, or is converted from PHY layer information, in this architecture, higher-layer signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by both the DU and the CU. It is understood that an access network device can be a CU node, a DU node, or a device that includes both a CU node and a DU node. In addition, the CU may be classified as an access network device in a radio access network (RAN), or may be classified as an access network device in a core network (CN), which is not limited here.

[0106] The terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiments of the present application may be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. In this application, the aforementioned terminal devices and chips applicable to the aforementioned terminal devices are collectively referred to as terminal devices. It should be understood that the embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal devices.

[0107] Figure 1 Two access network devices and one terminal device are shown as an example. Optionally, the communication system 100 may include at least one access network device and each access network device may include a different number of terminal devices within its coverage area, which is not limited in this embodiment of the present application. Optionally, the wireless communication system 100 may also include other network entities such as a network controller and a mobility management entity, which is not limited in this embodiment of the present application.

[0108] In a mobile communication system, after a terminal device establishes an RRC connection with the network and enters the RRC connected state (RRC_CONNECTED), if radio link failure (RLF), handover failure, integrity check failure, RRC connection reconfiguration failure, etc. occur, the RRC reestablishment procedure may be triggered. This procedure aims to reestablish the RRC connection, including the resumption of signaling radio bearer 1 (SRB1) operation and secure reactivation to restore service continuity. During this process, the terminal device first performs a cell selection process to select a suitable cell and initiates the RRC reestablishment procedure.

[0109] In the description of the embodiments of this application, Figure 1 Taking the terminal device 130 in the example, the RRC re-establishment process is described. Figure 1 As shown, the terminal device 130 establishes an RRC connection with the base station 110 through cell 1 and enters the RRC connected state. In certain circumstances (for example, handover failure), the RRC re-establishment process will be triggered. At this time, the terminal device 130 performs a cell selection process, for example, selects cell 2 to initiate the RRC re-establishment process. Cell 2 is a cell under the base station 120. That is to say, at this time, the terminal device 130 will initiate the RRC re-establishment process with the base station 120 through cell 2 (or in cell 2).

[0110] In the embodiments of the present application, a terminal device initiates an RRC re-establishment process at a new base station. The new base station may be referred to as the target base station (target gNB) of the terminal device, and the cell accessed may be referred to as the target cell of the terminal device. For example, if terminal device 130 initiates an RRC re-establishment process with base station 120 via cell 2, cell 2 is the target cell of terminal device 130, and base station 120 is the target base station of terminal device 130.

[0111] In this embodiment of the present application, the base station to which a terminal device last establishes a connection before initiating the RRC re-establishment process may be referred to as the terminal device's last serving gNB, anchor gNB, or source gNB, and the last connected cell may be referred to as the terminal device's source cell. For example, cell 1 is the source cell of terminal device 130, and base station 110 is the source base station of terminal device 130.

[0112] The target base station has the context of the terminal device, which is a necessary condition for the terminal device to complete RRC re-establishment with the target base station. The context of the terminal device includes at least one of the security configuration, RRC configuration, and mobility restriction list of the terminal device. After the target base station determines that it does not have the context of the terminal device, in order to complete RRC re-establishment, it can request the context of the terminal device from the source base station. Figure 2 , further explains the RRC re-establishment process of the terminal device.

[0113] Figure 2 It is a schematic interaction diagram of the RRC re-establishment process of the terminal device. Figure 2 The terminal device, target base station, and source base station in the above Figure 1 The terminal device 130, base station 120, and base station 110 in it. Figure 2 The process includes steps 210 to 250, the specific contents of which are as follows:

[0114] Step 210: After being in the RRC connected state and the security mode of the access layer has been activated, the terminal device may re-establish the RRC under certain circumstances (for example, handover failure). At this time, the terminal device can determine the target cell through the cell selection process, and send an RRC re-establishment request (RRCReestablishment Request) message to the target base station through the selected target cell.

[0115] The RRC re-establishment request message may carry three information elements, namely:

[0116] (1) UE Identity: This is used to obtain UE information and help lower layers mitigate contention issues. The UE Identity here is a ReestabUE-Identity, or a reconstructed UE Identity.

[0117] (2) Reestablishment Cause: This field may contain different reasons depending on the scenario, such as handover failure, radio link failure, integrity protection check failure, or RRC connection reconfiguration failure.

[0118] (3) Reserved bit: The reserved bit is a bit that is not configured in the entire message and can be used for the expansion of subsequent communication technologies.

[0119] Optionally, the terminal device identifier may include the following three information elements:

[0120] (1) Cell Radio Network Temporary Identifier (c-RNTI). A terminal device in a cell is assigned a unique identifier within the cell during random access or handover procedures. During reestablishment, the c-RNTI carried is the identifier of the terminal device in the source cell.

[0121] (2) Physical cell identity (PCI): The terminal device can obtain the cell's PCI through methods such as the cell synchronization signal found during the cell search process.

[0122] The PCI consists of the primary synchronization signal (PSS) and the secondary synchronization signal (SSS). Terminal devices use different PCIs to distinguish different wireless signals. For example, LTE systems provide 504 PCIs, ranging from 0 to 503, while 5G systems provide 1008 PCIs, ranging from 0 to 1007.

[0123] The PCI is a cell identifier and a local identifier. Different cells use different frequencies for network deployment, so the frequency plus the PCI can be used to distinguish between different cells. If two adjacent cells have the same frequency and PCI, terminal devices will be confused about the PCI. As long as there is a difference in either the frequency or the PCI, the terminal device can distinguish between two different cells. When deploying networks, operators should avoid deploying adjacent cells with the same frequency and PCI. During the reestablishment process, the PCI carried is the PCI of the source cell.

[0124] (3) Short message authentication code for integrity (shortMAC-I) captures a portion of the MAC-I. MAC-I calculation parameters include the PCI of the source cell, the c-RNTI of the source cell, and the cell identity of the target cell selected by the terminal device (e.g., NR cell identity). The terminal device inputs these three parameters into the algorithm, and the output is shortMAC-I. During the reestablishment process, shortMAC-I is used to verify whether the base station is the source base station and whether the terminal device is a legitimate terminal device.

[0125] Optionally, the RRC re-establishment request message may be the third message (Msg3) in a four-step contention random access procedure.

[0126] In step 220, the target base station receives the RRC re-establishment request message sent by the terminal device, and after determining that it does not have the context of the terminal device, the target base station will determine which base stations to send a retrieve UE context request message to based on the source cell PCI carried in the RRC re-establishment request message. The retrieve UE context request message is used to request the context of the terminal device.

[0127] Specifically, the target base station will establish an XN interface with the surrounding neighboring base stations for communication. During the XN interface establishment process, the two base stations will exchange each other's cell information through XN interface establishment request (XN setup request) message and XN interface establishment response (XN setup response) message, including the cell's PCI and cell global identifier (CGI) and other information.

[0128] Because the PCI is a local identifier, the target base station may determine multiple base stations based on the source cell PCI carried in the RRC re-establishment request message (i.e., the multiple base stations all include cells with the same PCI as the source cell). Each of these multiple base stations may be the source base station of the terminal device, and therefore these multiple base stations can be referred to as candidate base stations. Since the target base station cannot determine which of the multiple candidate base stations is the source base station of the terminal device, the target base station can send a restore terminal device context request message to each of the multiple candidate base stations.

[0129] As an example, the PCI of the source cell can be recorded as PCI#1. After receiving the RRC re-establishment request message, the target base station determines multiple candidate base stations, each of which includes at least one cell with PCI#1. At this time, the target base station can send a restore terminal device context request message to each of the multiple candidate base stations.

[0130] The restore terminal device context request message may carry the c-RNTI, source cell PCI and shortMAC-I, and target cell ID carried in the RRC re-establishment request message. These parameters are used by the candidate base station that receives the restore terminal device context request message to determine whether it has context information for the terminal device.

[0131] In step 230, the candidate base station determines whether it has the context of the terminal device based on the received Retrieve UE Context Request message. If so, it sends a Retrieve UE Context Response message containing the context information of the terminal device to the target base station. If it does not have the context of the terminal device, it sends a Retrieve UE Context Failure message to the target base station.

[0132] Exemplarily, the process of a candidate base station determining whether it has the context of the terminal device can be as follows: the base station uses the PCI of the source cell (denoted as PCI#1) to determine at least one cell (the cell is denoted as cell#1, and the PCI of cell#1 is PCI#1) based on the various parameters in the received restore terminal device context request message, and then uses PCI#1, c-RNTI, and the cell identifier of the target cell as input parameters, and uses the algorithm corresponding to cell#1 to calculate the shortMAC-I, and compares it with the shortMAC-I in the restore terminal device context request message. If they are the same, the verification is successful (that is, the terminal device is determined to be a user under cell#1), and the candidate base station knows that it does have the context of the terminal device, that is, it can determine that it is the source base station of the terminal device, and at this time it will send a restore terminal device context response message carrying the terminal device context information to the target base station. On the contrary, if the two are not the same, that is, the verification fails (it is determined that the terminal device is not a user under cell#1), then the candidate base station does not have the context of the terminal device, and at this time sends a restore UE context failure message to the target base station.

[0133] It should be understood that using the PCI of the source cell (denoted as PCI#1) may determine multiple cells under the same candidate base station (that is, there may be multiple cells with PCI of PCI#1 under the candidate base station). At this time, PCI#1, c-RNTI, and the cell identifier of the target cell can be used as input parameters, and the algorithm corresponding to each of the multiple cells is used to calculate multiple shortMAC-Is in sequence, and then the shortMAC-I in the terminal device context recovery request message is compared in sequence. The cell that is successfully matched is the true source cell of the terminal device, that is, at this time, it can be determined that the terminal device is a user under the cell that is successfully matched, so that the identity of the terminal device can be accurately determined, and the context information of the terminal device can be accurately obtained. If the multiple cells all fail to match, it means that the terminal device is not a user under the multiple cells, that is, the candidate base station is not the source base station of the terminal device, and the context information of the terminal device does not exist.

[0134] In step 240, upon receiving the terminal device context restore response message from the source base station, which carries the terminal device context, the target base station completes relevant processing based on the context and sends an RRC Reestablishment message to the terminal device, which contains the target base station's secret key. This is to allow future communications between the base station and the terminal device to be encrypted and integrity protected. Upon receiving the RRC Reestablishment message, the terminal device stops the relevant timers, restores SRB1, reactivates security, including integrity protection and encryption, and performs measurement processing.

[0135] In step 250, the terminal device sends an RRC Reestablishment Complete message to the target base station. After the target base station receives the message, the RRC reestablishment process ends.

[0136] The RRC re-establishment process described above is used in LTE systems. In LTE systems, a base station may have 24 or fewer cells, and base stations in LTE systems have a wide coverage area. Therefore, during the RRC re-establishment process, the target base station does not need to send many candidate base stations, and the corresponding signaling overhead is also low.

[0137] However, in 5G systems, compared to LTE systems, the number of candidate base stations to be sent by the target base station may increase significantly due to the following reasons:

[0138] 1. The frequency is high, reaching over 30GHz in the high frequency band. High frequencies inevitably lead to rapid attenuation, so the coverage area of each base station is small. Compared with LTE base stations, 5G base stations can be much denser in the same area.

[0139] 2. Compared with 4G base stations, each 5G base station may have many more cells.

[0140] With the surge in the number of candidate base stations, the target base station needs to send terminal device context recovery request messages to a large number of candidate base stations, and subsequently receives a large number of terminal device context recovery failure messages sent by non-source base stations, thereby wasting signaling overhead and reducing communication efficiency.

[0141] In response to the above problems, the embodiments of the present application provide a communication method, a communication device and a communication system, which improve and optimize the above-mentioned RRC re-establishment process to reduce the number of candidate base stations, thereby saving signaling overhead and improving communication efficiency.

[0142] The following describes the communication method provided in an embodiment of the present application in conjunction with the accompanying drawings. The terminal device, the first base station, and the second base station in the embodiment may correspond to the terminal device 130, the base station 110, and the base station 120 in the aforementioned system 100, and the first cell and the second cell may correspond to the cell 1 and the cell 2 in the aforementioned system 100.

[0143] Figure 3 This is a schematic flow chart of the communication method 300 provided by this application. Figure 3 The communication method 300 provided in an embodiment of the present application is described. The method 300 includes:

[0144] In step 310, the terminal device determines that the RRC connection with the first cell has failed, where the first cell belongs to the first base station.

[0145] In step 320, the terminal device sends a first message to the second base station. The first message is used to request the re-establishment of the RRC connection. The first message carries first indication information and first auxiliary indication information. The first indication information includes the physical cell identifier PCI of the first cell, and the first auxiliary indication information includes information used to determine the first base station. In some possible implementations, the information used to determine the first base station may also be referred to as information used to determine the first cell.

[0146] Correspondingly, in step 320, the second base station receives the first message sent by the terminal device.

[0147] Step 330: The second base station determines at least one candidate base station according to the first indication information and the first auxiliary indication information, where the at least one candidate base station includes the first base station.

[0148] In an embodiment of the present application, the terminal device establishes an RRC connection with the network through a first cell and enters an RRC connection state. The first cell belongs to a first base station, that is, the first base station is a serving base station for the terminal device. At this time, if a radio link failure, handover failure, integrity protection check failure, RRC reconfiguration failure, etc. occur, the RRC re-establishment process may be triggered. It should be understood that the present application does not limit the scenario in which the terminal device triggers the RRC re-establishment process, which may be any one of the aforementioned multiple situations or other situations.

[0149] The first base station is the base station that the terminal device last establishes a connection with before initiating the RRC re-establishment process. Therefore, the first base station in the embodiment of the present application can also be called the last serving base station, anchor base station, source base station, etc. of the terminal device.

[0150] Accordingly, the first cell is the cell to which the terminal device last establishes a connection before initiating the RRC re-establishment process. Therefore, the first cell in the embodiment of the present application can also be referred to as the last serving cell, anchor cell, source cell, etc. of the terminal device.

[0151] After the terminal device triggers the RRC re-establishment process, the terminal device will first perform a cell selection process. For example, in an embodiment of the present application, the terminal device will select the second cell under the second base station to initiate the RRC re-establishment process (that is, the terminal device will initiate the RRC re-establishment process with the second base station through the second cell). The second base station and the aforementioned first base station are two different base stations (in this case, the second cell and the first cell are also two different cells). This application does not impose any restrictions on the specific process of the terminal device performing cell selection. For example, please refer to the cell selection and reselection part of the protocol TS38.304 (Section 5.2 Cell selection and reselection).

[0152] In the embodiment of the present application, the terminal device initiates an RRC re-establishment process at a new base station. The new base station may be referred to as the target base station of the terminal device, and the cell accessed may be referred to as the target cell of the terminal device. In other words, the second cell here may also be referred to as the target cell of the terminal device, and the second base station may be referred to as the target base station of the terminal device.

[0153] At this time, the terminal device can send a first message to the second base station through the second cell. The first message is used to request to re-establish the RRC connection. The first message carries first indication information and first auxiliary indication information. The first indication information includes the physical cell identifier PCI of the first cell, and the first auxiliary indication information includes information used to determine the first base station.

[0154] Optionally, the first message may be an RRC re-establishment request message.

[0155] Optionally, the first message may also be an RRC reestablishment request message 1 (RRC ReestablishmentRequest 1).

[0156] Optionally, the first message may also carry the c-RNTI and shortMAC-I of the terminal device.

[0157] In an embodiment of the present application, in addition to first indication information indicating the PCI of the first cell, the first message also includes first auxiliary indication information, where the first auxiliary indication information includes information used to identify the first base station, i.e., the first auxiliary indication information can provide auxiliary indication for the first base station. The content indicated by the first auxiliary indication information should be different from the content indicated by the first indication information, i.e., the first auxiliary indication information indicates information other than the PCI of the first cell, or in other words, the first auxiliary indication information includes information other than the PCI of the first cell.

[0158] After receiving the first message, the second base station may determine at least one candidate base station according to the first indication information and the first auxiliary indication information in the first message, where the at least one candidate base station includes the first base station.

[0159] According to the communication method 300 provided in an embodiment of the present application, the second base station can determine the candidate base station based on the first indication information and the first auxiliary indication information. Since the PCI of the cell is a local identifier, compared with determining the candidate base station based only on the PCI of the first cell, the present application uses more message content to determine the candidate base station, thereby making the determination of the candidate base station more specific, and can control the number of candidate base stations determined by the second base station, reduce the number of determined candidate base stations, and reduce the number of terminal device context recovery request messages sent by the second base station and reduce the number of terminal device context recovery failure messages sent by the candidate base station, thereby saving signaling overhead and improving communication efficiency.

[0160] The following further introduces the first auxiliary indication information in the embodiment of the present application.

[0161] In an embodiment of the present application, the first auxiliary indication information includes information used to determine the first base station. The first auxiliary indication information may be information other than the PCI of the first cell. The second base station may determine candidate base stations based on the first auxiliary indication information and in combination with the first indication information, and the number of candidate base stations may be maintained within a reasonable range. The embodiment of the present application does not limit the specific content indicated by the first auxiliary indication information; any information may be used as long as it can be used to determine the first base station.

[0162] As an example, the first auxiliary indication information indicates at least one of the following information: frequency information of the first cell, cell global identifier (CGI) information of the first cell, and identification information of the first base station. The first auxiliary indication information is further described below according to different contents indicated by the first auxiliary indication information.

[0163] (1) The first auxiliary indication information indicates the frequency information of the first cell (ie, the first auxiliary indication information includes indication information of the frequency information of the first cell).

[0164] Specifically, for the frequency information of the LTE cell (ARFCN-ValueEUTRA), the maximum frequency value is 262143, which can be represented by 18 bits. For the frequency information of the 5G cell (ARFCN-ValueNR), the maximum frequency value is 3279165, which can be represented by 22 bits. The first auxiliary indication information can indicate the frequency information of the first cell. At this time, the first auxiliary indication information may include all or part of the frequency information of the first cell.

[0165] Here, the partial information of the frequency information of the first cell may be a partial numerical value of the frequency, or a partial bit value after conversion into binary. For example, the first cell may be a 5G cell, and the frequency numerical value is 3201111, and the corresponding binary numerical value is "1100001101100001010111". In this case, the first auxiliary indication information may include partial information of the frequency information of the first cell, and the partial information may be a partial numerical value of the frequency, such as the four-digit numerical value "3201" on the left, or the four-digit numerical value "1111" on the right, or the second to fifth digit numerical values "2011" in the middle, etc.

[0166] The partial information may also be the value of some bits after conversion to binary. For example, the partial information may be the value "110000" of the first six bits of the 22 bits, or the value "010111" of the last six bits. It may also be the value of other specific continuous or discontinuous bits, which is not limited in this application.

[0167] At this time, in step 320, the second base station can jointly determine the candidate base station based on the first indication information (i.e., the PCI (denoted as PCI#1) information of the first cell) and the first auxiliary indication information (i.e., the frequency point (denoted as ARF#1) information of the first cell).

[0168] The second base station can determine, based on the neighboring station information obtained during the XN interface establishment process, that base stations #1 to #9 all include a cell with PCI #1. At this point, the second base station can further screen these nine base stations based on the first auxiliary indication information. Specifically, the second base station can further determine whether the frequency of the cell with PCI #1 among base stations #1 to #9 is ARF #1. Only when both the PCI and the frequency match successfully can the corresponding base station be determined as a candidate base station.

[0169] For example, for base stations #1 to #9, only the cell with PCI #1 among base stations #1, #5, and #8 has a frequency of ARF #1. In this case, base stations #1, #5, and #8 can be determined as candidate base stations. Compared to determining candidate base stations based solely on the PCI of the first cell, the embodiment of the present application determines candidate base stations using both the PCI of the first cell and the frequency information of the first cell, significantly reducing the number of candidate base stations determined. This can reduce the number of terminal device context restore request messages and terminal device context restore failure messages sent, thereby saving signaling overhead and improving communication efficiency.

[0170] In this embodiment of the present application, the first auxiliary indication information indicates the frequency information of the first cell. The first auxiliary indication information may include an index value of the frequency of the first cell. In this case, the second base station can determine the frequency of the first cell based on the index value. Through the above configuration, the first auxiliary indication information can contain less content, which is conducive to saving signaling overhead.

[0171] Optionally, the terminal device may determine the index value corresponding to the frequency of the first cell based on a frequency-index list in the frequency information broadcast in the system information blocks 4 (SIB4) sent by the second base station.

[0172] In an embodiment of the present application, one possible implementation of the first auxiliary indication information indicating the frequency information of the first cell is to indicate attribute information of the frequency information of the first cell. In other words, the first auxiliary indication information can indicate attribute information of the frequency information of the first cell. It is understood that attribute information can also be called feature information, parameter information, etc. For example, attribute information can be parity information of the frequency (also called parity information).

[0173] In addition, the attribute information may also be information on the number of bits of the frequency point and the size of the frequency point value, etc., which is not limited in this application.

[0174] In some possible implementations, the first auxiliary indication information may indicate parity information of the frequency information of the first cell. The parity information here may include the parity characteristics of one or more bits of the frequency value, or the parity characteristics of one or more bits after the frequency value is converted into binary (i.e., "0" or "1").

[0175] Optionally, the first auxiliary indication information can occupy 1 bit, and on this bit, "0" is used to indicate that the value of a certain bit (for example, the last bit) of the frequency value of the first cell is an even number, and "1" is used to indicate that the value of the corresponding bit of the frequency value of the first cell is an odd number.

[0176] For example, the frequency value of the first cell is 3201111. At this time, the first auxiliary indication information can occupy 1 bit, and the value on this bit is "1", thereby indicating that the last digit of the frequency value of the first cell is an odd number (1).

[0177] For another example, the first auxiliary indication information may occupy 1 bit, and the value of the bit is "0", thereby indicating that the second bit of the frequency point number of the first cell is an even number (2).

[0178] Optionally, the first auxiliary indication information can occupy 1 bit, and on this bit, "0" is used to indicate that the value of a certain bit (for example, the last bit) after the frequency value of the first cell is converted into binary is an even number (that is, the value of this bit is "0"), and "1" is used to indicate that the value of the corresponding bit of the frequency value of the first cell is an odd number (that is, the value of this bit is "1").

[0179] For example, the frequency value of the first cell is 3201111, and the corresponding binary value is "1100001101100001010111". At this time, the first auxiliary indication information can occupy 1 bit, and the value on this bit is "1", thereby indicating that the last digit of the binary number is an odd number (that is, the value is 1).

[0180] For another example, the first auxiliary indication information may occupy 1 bit, and the value of the bit is "0", thereby indicating that the value of the third bit of the binary number is an even number (ie, the value is 0).

[0181] Optionally, the first message may be an RRC re-establishment request message, and the one bit occupied by the first auxiliary indication information may be a reserved (spare) bit, thereby not changing the format of the existing RRC re-establishment request message and having greater versatility.

[0182] At this time, in step 320, the second base station can jointly determine a candidate base station based on the PCI of the first cell and the parity information of the frequency information of the first cell. For ease of understanding, the following description uses the first auxiliary indication information indicating the parity of the last digit of the frequency number of the first cell as an example.

[0183] Optionally, the frequency information of each cell is randomly allocated according to the operator's network planning, which can be roughly understood as the same probability of odd and even. In the embodiment of the present application, the first auxiliary indication information indicates the parity of the last digit of the frequency number of the first cell, which can reduce about half of the candidate cells, and then reduce half of the candidate base stations. It can enable the first base station to send half fewer terminal device context recovery request messages, and can also reduce half of the candidate base stations to send terminal device context recovery failure messages, which can save a lot of signaling overhead.

[0184] For example, the second base station may determine, based on the neighboring station information obtained during the XN interface establishment process, that base stations #1 to #9 all include a cell with a PCI of PCI#1. At this point, the nine base stations may be further screened based on the first auxiliary indication information, assuming that the first auxiliary indication information indicates the parity of the last digit of the frequency point value corresponding to the first cell. Exemplarily, the second base station may further determine whether the last digit of the frequency point value of the cell with a PCI of PCI#1 among base stations #1 to #9 is an odd number or an even number, and match the last digit with the parity of the last digit of the frequency point value of the first cell. Base stations for which both the PCI and the parity of the last digit of the frequency point value successfully match are determined as candidate base stations.

[0185] For example, if the frequency value of the first cell ends with an odd number, for base stations #1 to #9, only the frequency value of the cell with PCI PCI#1 among base stations #1, #5, and #8 ends with an odd number. In this case, base stations #1, #5, and #8 can be determined as candidate base stations. Compared to determining candidate base stations based solely on the PCI of the first cell, the embodiment of the present application determines candidate base stations by jointly determining the PCI of the first cell and the frequency parity information of the first cell, significantly reducing the number of determined candidate base stations. This can reduce the number of terminal device context restore request messages and terminal device context restore failure messages sent, thereby saving signaling overhead and improving communication efficiency.

[0186] Optionally, the first auxiliary indication information may also occupy multiple bits, and indicate whether the values on multiple bits of the frequency value of the first cell are even or odd by whether the values on multiple bits are "1" or "0", or indicate whether the values on multiple bits of the frequency value of the first cell are even (that is, the value of the bit is "0") or odd (that is, the value of the bit is "1") after the frequency value of the first cell is converted into binary. This application does not limit this.

[0187] For example, the frequency value of the first cell is 3201111. At this time, the first auxiliary indication information can occupy 3 bits, and the value on the 3 bits is "100", thereby indicating that the first three digits of the frequency value of the first cell are odd, even, and even respectively.

[0188] (2) The first auxiliary indication information indicates the CGI information of the first cell (ie, the first auxiliary indication information includes indication information of the CGI information of the first cell).

[0189] The CGI is a cell global identifier that uniquely identifies a cell. The LTE cell CGI consists of 28 bits, while the 5G cell CGI consists of 36 bits. The first auxiliary indication information may indicate the CGI information of the first cell and may include all or part of the CGI information of the first cell.

[0190] Here, the first auxiliary indication information may include partial information of the CGI information of the first cell.

[0191] For example, the first cell is a 5G cell, and the CGI of the first cell consists of a total of 36 bits. The partial information can be the value of any one or more bits of the 36 bits. For example, the partial information can be the value of the first few (for example, the first 4, 5, 6, 8) bits of the 36 bits, or the value of the last few (for example, the last 4, 5, 6, 8) bits. In addition, it can also be a value on other continuous or discontinuous specific bits (for example, the value of several continuous bits in the middle). This application does not limit this.

[0192] At this time, in step 320, the second base station can jointly determine the candidate base station based on the first indication information (ie, the PCI information of the first cell) and the first auxiliary indication information (ie, the CGI information of the first cell).

[0193] The second base station can determine, based on the neighboring station information obtained during the XN interface establishment process, that base stations #1 to #9 all include a cell with a PCI of PCI#1. At this point, the second base station can further screen the nine base stations based on the first auxiliary indication information. For example, the second base station can further obtain the CGI information of the cells with a PCI of PCI#1 from base stations #1 to #9, and match it with the CGI information of the first cell (i.e., determine whether the corresponding bit values are the same). The second base station can then determine the base stations for which both the PCI and CGI successfully match as candidate base stations.

[0194] For example, for base stations #1 to #9, only the CGI of the cell with PCI #1 among base stations #2, #3, and #4 successfully matches the CGI of the first cell (i.e., the corresponding bit values are the same).

[0195] At this time, base stations #2, #3, and #4 can be determined as candidate base stations. Compared to determining candidate base stations based solely on the PCI of the first cell, the embodiment of the present application determines candidate base stations using both the PCI of the first cell and the CGI information of the first cell, significantly reducing the number of determined candidate base stations. This can reduce the number of terminal device context restore request messages and terminal device context restore failure messages sent, thereby saving signaling overhead and improving communication efficiency.

[0196] Similarly, in an embodiment of the present application, the first auxiliary indication information indicates the CGI information of the first cell and also includes indicating attribute information of the CGI information of the first cell. In other words, the first auxiliary indication information may also indicate attribute information of the CGI information of the first cell. For example, the attribute information may be parity information of the CGI.

[0197] For example, the first auxiliary indication information may indicate the parity information of the CGI information of the first cell. The parity information here may include the parity characteristics of one or more bits in the CGI (ie, "0" or "1").

[0198] Optionally, the first auxiliary indication information can occupy 1 bit, and on this bit, "0" is used to indicate that the value of a certain bit (for example, the first bit, the last bit, or any bit in the middle) of the CGI of the first cell is an even number (i.e., "0"), and "1" is used to indicate that the value of the corresponding bit of the frequency point value of the first cell is an odd number (i.e., "1").

[0199] Optionally, the one bit occupied by the first auxiliary indication information may be a reserved bit, thereby not changing the format of the existing RRC re-establishment request message and having greater versatility.

[0200] At this time, in step 320, the second base station can jointly determine the candidate base station based on the PCI of the first cell and the parity information of the CGI information of the first cell. For ease of understanding, the following is an example of indicating the parity of the last digit of the CGI of the first cell using the first auxiliary indication information.

[0201] Optionally, the CGI of each cell is randomly allocated according to the operator's network planning, which can be roughly understood as the same probability of odd and even. In the embodiment of the present application, the first auxiliary indication information indicates the parity of the last digit of the CGI of the first cell, which can reduce about half of the candidate cells, and then reduce half of the candidate base stations. It can enable the first base station to send half fewer terminal device context recovery request messages, and can also reduce half of the candidate base stations to send terminal device context recovery failure messages, which can save a lot of signaling overhead.

[0202] For example, the second base station may determine, based on the neighboring station information obtained during the XN interface establishment process, that base stations #1 to #9 all include a cell with a PCI of PCI#1. In this case, the second base station may further screen these nine base stations based on the first auxiliary indication information. Specifically, the second base station may further determine whether the last digit of the CGI of the cell with PCI#1 among base stations #1 to #9 is an odd number or an even number, and determine the base station for which both the PCI and the parity of the last digit of the frequency point successfully match as a candidate base station.

[0203] For example, if the last digit of the CGI of the first cell is an even number, for base stations #1 to #9, only the cell with PCI #1 among base stations #1, #5, and #8 has an even number at the end of its CGI. In this case, base stations #1, #5, and #8 can be determined as candidate base stations. Compared to determining candidate base stations based solely on the PCI of the first cell, the embodiment of the present application determines candidate base stations by jointly determining the PCI of the first cell and the odd and even number information of the CGI of the first cell, significantly reducing the number of candidate base stations determined. This can reduce the number of terminal device context recovery request messages and terminal device context recovery failure messages sent, thereby saving signaling overhead and improving communication efficiency.

[0204] Optionally, the first auxiliary indication information may also occupy multiple bits, and whether the values on the multiple bits of the CGI of the first cell are even or odd is indicated by whether the values on the multiple bits are "1" or "0". This application does not limit this.

[0205] For example, the first auxiliary indication information can occupy 3 bits, and the value of the 3 bits is "100", so as to indicate that the values of any three digits (such as the first three digits, the last three digits, or the continuous or discontinuous three digits in the middle) of the CGI of the first cell are odd, even, and even, respectively.

[0206] (3) The first auxiliary indication information indicates the identification information of the first base station (ie, the first auxiliary indication information includes indication information of the identification information of the first base station).

[0207] Depending on the scenario, the LTE base station identifier can be composed of 18 / 20 / 21 / 28 bits, and the 5G base station identifier can be composed of 22-32 bits. The first auxiliary indication information can indicate the identification information of the first base station. In this case, the first auxiliary indication information can include all or part of the identification information of the first base station.

[0208] Here, the first auxiliary indication information may include partial information of the identification information of the first base station.

[0209] For example, the first base station is a 5G base station, and the identification of the first base station consists of a total of 32 bits. The partial information can be the value of any one or more bits of the 32 bits. For example, the partial information can be the value of the first few (for example, the first 4, 5, 6, 8) bits of the 32 bits, or the value of the last few (for example, the last 4, 5, 6, 8) bits. In addition, it can also be a value on other continuous or discontinuous specific bits (for example, the value of several continuous bits in the middle). This application does not limit this.

[0210] At this time, in step 330, the second base station can jointly determine the candidate base station based on the first indication information (ie, the PCI information of the first cell) and the first auxiliary indication information (ie, the identification information of the first base station).

[0211] The second base station can determine, based on the neighboring station information obtained during the XN interface establishment process, that base stations #1 to #9 all include a cell with a PCI of PCI #1. At this point, the nine base stations can be further screened based on the first auxiliary indication information. Specifically, the second base station can further obtain the identification information of base stations #1 to #9 and match it with the identification information of the first base station (i.e., determine whether the values of the corresponding bits are the same), and determine the base station whose PCI of the first cell and the identification of the first base station both successfully match as a candidate base station.

[0212] For example, for base stations #1 to #9, only the identifiers of base stations #2, #3, and #4 successfully match the identifier of the first base station (i.e., the corresponding bit values are the same). In this case, base stations #2, #3, and #4 can be determined as candidate base stations. Compared to determining candidate base stations based solely on the PCI of the first cell, the embodiment of the present application determines candidate base stations through the PCI of the first cell and the identification information of the first base station, so that the number of determined candidate base stations is significantly reduced, and the number of terminal device context recovery request messages and terminal device context recovery failure messages sent can be reduced, thereby saving signaling overhead and improving communication efficiency.

[0213] Similarly, in this embodiment of the present application, the first auxiliary indication information indicates the identification information of the first base station and also includes indicating attribute information of the identification information of the first base station. In other words, the first auxiliary indication information may also indicate attribute information of the identification information of the first base station. For example, the attribute information may be parity information of the identification information of the first base station.

[0214] Specifically, the first auxiliary indication information may indicate the parity information of the identification information of the first base station. The parity information here may include the parity characteristics of one or more bits in the identification of the first base station (ie, "0" or "1").

[0215] Optionally, the first auxiliary indication information can occupy 1 bit, and on this bit, "0" is used to indicate that the value of a certain bit (for example, the first bit, the last bit, or any bit in the middle) of the identifier of the first base station is an even number (i.e., "0"), and "1" is used to indicate that the value of the corresponding bit of the frequency value of the first cell is an odd number (i.e., "1").

[0216] Optionally, the one bit occupied by the first auxiliary indication information may be a reserved bit, thereby not changing the format of the existing RRC re-establishment request message and having greater versatility.

[0217] At this time, in step 320, the second base station can jointly determine a candidate base station based on the PCI of the first cell and the parity information of the identification information of the first base station. For ease of understanding, the following example uses the first auxiliary indication information to indicate the parity of the last digit of the identification information of the first base station as an example.

[0218] Optionally, the identifiers of each base station are usually randomly assigned according to the operator's network planning, which can be roughly understood as the same probability of odd and even numbers. In the embodiment of the present application, the first auxiliary indication information indicates the parity of the last digit of the identifier of the first base station, which can reduce the number of candidate base stations by about half, and can enable the first base station to send half fewer terminal device context recovery request messages, and can also reduce half of the candidate base stations to send terminal device context recovery failure messages, which can save a lot of signaling overhead.

[0219] For example, the second base station may determine, based on the neighboring station information obtained during the XN interface establishment process, that base stations #1 to #9 all include a cell with a PCI of PCI #1. In this case, the second base station may further screen these nine base stations based on the first auxiliary indication information. Specifically, the second base station may further determine whether the last digit of the base station identifiers of base stations #1 to #9 is an odd number or an even number, and determine as a candidate base station the base station for which both the PCI and the parity of the last digit of the base station identifier successfully match.

[0220] For example, if the last digit of the identifier of the first base station is an even number, for base stations #1 to #9, only the last digit of the identifiers of base stations #1, #5, and #8 is an even number. In this case, base stations #1, #5, and #8 can be determined as candidate base stations. Compared to determining candidate base stations based solely on the PCI of the first cell, the embodiment of the present application jointly determines candidate base stations using the PCI of the first cell and the odd and even number information of the identifier of the first base station, significantly reducing the number of candidate base stations determined. This can reduce the number of terminal device context recovery request messages and terminal device context recovery failure messages sent, thereby saving signaling overhead and improving communication efficiency.

[0221] Optionally, the first auxiliary indication information may also occupy multiple bits, and whether the values on the multiple bits of the first base station identifier are even or odd is indicated by whether the values on the multiple bits are "1" or "0". This application does not limit this.

[0222] For example, the first auxiliary indication information can occupy 3 bits, and the value of the 3 bits is "100", so as to indicate that the values of any three digits (such as the first three digits, the last three digits, or the continuous or discontinuous three digits in the middle) of the identification of the first base station are odd, even, and even, respectively.

[0223] The previous article has provided a detailed description of how the first auxiliary indication information separately indicates the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station. It should be understood that the first auxiliary indication information of this application can also indicate multiple information at the same time, and this application does not limit this.

[0224] Optionally, the first auxiliary indication information may indicate two or three of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0225] Optionally, the first auxiliary indication information may indicate attribute information of two or three of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0226] For example, the first auxiliary indication information may indicate parity information of two or three of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0227] As an example, the first auxiliary indication information may occupy one bit, and the value of the bit is "1" or "0" to indicate that the frequency of the first cell and the last digit of the first cell CGI are both odd or even.

[0228] As another example, the first auxiliary indication information may occupy two bits, and the values of the two bits being "1" or "0" indicate whether the frequency of the first cell and the last digit of the CGI of the first cell are odd or even. As an example, the value of the two bits may be "10", indicating that the last digit of the frequency of the first cell is an odd number and the last digit of the CGI of the first cell is an even number.

[0229] Optionally, the first auxiliary indication information may indicate a logical operation result of two or three of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station. This embodiment of the application does not limit the specific indication method. For example, the first auxiliary indication information may indicate the sum of the number of digits of two or three of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0230] For another example, the first auxiliary indication information may indicate the sum of one or more digits of two or three of the frequency of the first cell, the CGI of the first cell, and the identifier of the first base station.

[0231] It can be understood that when the first auxiliary indication information includes part or all of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station, the first auxiliary indication information may require multiple bits. As a result, compared with the existing RRC re-establishment request message, the first message of the present application may contain more content. Therefore, in some cases, the first message of the present application can also be understood as an "expanded version" of the RRC re-establishment request message.

[0232] Since the first message of the present application may contain more content than the existing RRC re-establishment request message, not all base stations may support receiving the first message of the present application. For example, some older base stations do not have the ability to receive (or parse) such large-format messages. For another example, some base stations are not allowed to receive such large-format messages. Based on the above reasons, optionally, before the terminal device sends the first message to the second base station, the method 300 provided in the embodiment of the present application further includes step 340.

[0233] In step 340, the second base station sends third indication information to the terminal device, where the third indication information is used to determine whether the second base station supports (or allows) receiving the first auxiliary indication information;

[0234] In step 320, when it is determined that the second base station supports receiving the first auxiliary indication information, the terminal device sends a first message to the second base station.

[0235] For example, a terminal device may first receive third indication information sent by a second base station. This third indication information is used to determine whether the second base station supports receiving the first auxiliary indication information. If the terminal device determines, based on the third indication information, that the second base station supports receiving the first auxiliary indication information, the terminal device sends a first message to the second base station. This prevents the terminal device from sending invalid signaling, saves signaling overhead, and improves communication efficiency. In an embodiment of the present application, the third indication information indicates that the second base station supports receiving the first auxiliary indication information, in which case the terminal device sends the first message to the second base station. Optionally, if the second base station does not support receiving the first auxiliary indication information, the third indication information may be sent or not. In other words, if the third indication information is not sent, it is assumed that the second base station does not support receiving the first auxiliary indication information. Optionally, in other embodiments, the third indication information may indicate that the second base station does not support receiving the first auxiliary indication information. In this case, the terminal device may not send the first message to the second base station. Optionally, if the second base station supports receiving the first auxiliary indication information, the third indication information may be sent or not. In other words, if the third indication information is not sent, it is assumed that the second base station supports receiving the first auxiliary indication information.

[0236] Optionally, the third indication information may be carried in a system message.

[0237] Optionally, the third indication information may be carried in system information blocks 1 (SIB1).

[0238] For example, the third indication information may reuse the usefullResume information element in the existing SIB1 for indication.

[0239] For another example, the third indication information may be added to SIB1 as a new information element.

[0240] It should be understood that there is no logical order between step 310 and step 340. This application does not limit the execution order of step 310 and step 340. Step 340 can be executed before step 310 or after step 310. Step 310 and step 340 can also be executed simultaneously.

[0241] Optionally, step 340 is performed after step 310, that is, after determining that the RRC connection with the first cell has failed, the terminal device monitors the broadcast message of the neighboring cell and receives the third indication information through the broadcast message.

[0242] The previous article has made a detailed introduction to how the second base station determines the candidate base station to reduce the number of candidate base stations, thereby saving signaling overhead. Figure 3, describes how the second base station requests the context of the terminal device from the candidate base station. Figure 3 As shown, the method 300 provided in the embodiment of the present application also includes steps 350 , 360 , and 370 .

[0243] Step 350: The second base station determines a second message according to the first indication information and the first auxiliary indication information, where the second message is used to request the context of the terminal device.

[0244] Step 360: The second base station sends a second message to the candidate base station;

[0245] Accordingly, in step 360, the candidate base station receives the second message sent by the second base station.

[0246] Step 370: The candidate base station determines whether there is a context of the terminal device according to the second message.

[0247] Specifically, in an embodiment of the present application, the second base station may determine a second message based on the first indication information and the first auxiliary indication information carried in the first message, where the second message is used to request the context of the terminal device. The second base station may send the second message to each of the at least one determined candidate base station, where the second message is used to request the context of the terminal device.

[0248] It should be understood that Figure 3 Only one candidate base station is shown in the figure. In actual scenarios, there may be multiple candidate base stations. Since the second base station does not know which one of the multiple candidate base stations is the first base station, the second base station can send a second message to each of the multiple candidate base stations to request the context of the terminal device.

[0249] The content included in the second message may be different depending on the content included in the first auxiliary indication information.

[0250] Optionally, when the first auxiliary indication information is indication information of the identification information of the first base station, the second message may include second indication information, and the second indication information includes the PCI of the first cell. The second indication information may be the same as the content of the first indication information.

[0251] Optionally, when the first auxiliary indication information includes the frequency information of the first cell and / or the indication information of the CGI information of the first cell, the second message may include, in addition to the second indication information, second auxiliary indication information, and the second auxiliary indication information includes information used to determine the first cell.

[0252] It is easy to understand that the content indicated by the second auxiliary indication information should be different from the content indicated by the second indication information, that is, the second auxiliary indication information indicates information other than the PCI of the first cell, or the second auxiliary indication information includes information other than the PCI of the first cell.

[0253] The second auxiliary indication information can be determined based on the first indication information and the first auxiliary indication information. The content included in the second auxiliary indication information can be the same as or different from the content included in the first auxiliary indication information, and this application does not limit this.

[0254] For example, the first auxiliary indication information may include the frequency information of the first cell, in which case the second auxiliary indication information may include indication information of the frequency information of the first cell; alternatively, the second base station may determine the CGI of the first cell based on the PCI and frequency information of the first cell, in which case the second auxiliary indication information may also include indication information of the CGI information of the first cell.

[0255] For another example, the first auxiliary indication information may include the CGI information of the first cell, in which case the second auxiliary indication information may include indication information of the CGI information of the first cell; alternatively, the second base station may determine the frequency of the first cell based on the PCI and CGI information of the first cell, in which case the second auxiliary indication information may also include indication information of the frequency information of the first cell.

[0256] That is, the second auxiliary indication information may indicate at least one of the frequency information of the first cell and the CGI information of the first cell.

[0257] For example, the second auxiliary indication information may include all or part of the frequency information of the first cell.

[0258] For another example, the second auxiliary indication information may include all or part of the CGI information of the first cell.

[0259] For another example, the second auxiliary indication information may include attribute information of the frequency information of the first cell and / or attribute information of the CGI information of the first cell.

[0260] Optionally, the attribute information may be parity information.

[0261] The frequency information of the first cell and the CGI information of the first cell contained in the second auxiliary indication information can be understood by referring to the frequency information of the first cell and the CGI information of the first cell contained in the aforementioned first auxiliary indication information, and this application will not repeat them here.

[0262] In the embodiment of the present application, after determining the second message, the terminal device sends the second message to the candidate base station. The candidate base station can determine whether there is a context of the terminal device based on the second message.

[0263] Optionally, the second message may be a terminal device context restoration request message.

[0264] Optionally, the second message may also be a retrieve UE context request message 1 (retrieve UE context request 1).

[0265] Optionally, the second message also carries information such as the c-RNTI, shortMAC-I and identifier of the target cell of the terminal device.

[0266] Optionally, the second message includes second indication information, and the candidate base station then determines whether the context of the terminal device exists based on the second indication information.

[0267] Specifically, the second indication information indicates that the PCI of the first cell is PCI#1. The candidate base station can use PCI#1, c-RNTI, and the cell identifier of the second cell as input parameters, and use the algorithm corresponding to the cell with PCI#1 under the candidate base station to calculate the shortMAC-I, and compare it with the shortMAC-I in the second message. If they are the same, the verification is successful (i.e., it is determined that the terminal device is a user under the cell), and the cell is the first cell. The candidate base station knows that it does have the context of the terminal device, and the candidate base station is the first base station. At this time, it will send a recovery terminal device context response message carrying the terminal device context information to the second base station. On the contrary, if the two are not the same, that is, the verification fails (it is determined that the terminal device is not a user under the cell), then the candidate base station does not have the terminal device context, and at this time, a recovery terminal device context failure message is sent to the second base station.

[0268] It should be understood that there may be multiple cells with PCI # 1 under the same candidate base station. In this case, PCI # 1, c-RNTI, and the cell identifier of the second cell should be used as input parameters, and the algorithm corresponding to each of the multiple cells should be used to calculate multiple shortMAC-Is in sequence. Then, the shortMAC-I in the second message is compared in sequence. The cell with a successful match is the first cell. In this way, the identity of the terminal device can be accurately determined, and the context information of the terminal device can be accurately obtained. If the multiple cells all fail to match, it means that the terminal device is not a user under the multiple cells, that is, the candidate base station is not the first base station, and there is no context information of the terminal device.

[0269] Optionally, the second message includes second indication information and second auxiliary indication information, such as Figure 3 As shown, at this time in step 370, the candidate base station determines whether there is a context of the terminal device based on the second indication information and the second auxiliary indication information.

[0270] Referring to the above description, it can be seen that there may be multiple cells with PCI#1 under the same candidate base station. Compared with the aforementioned method of determining whether the context of the terminal device exists only based on the PCI of the first cell, the embodiment of the present application can simultaneously determine whether the context of the terminal device exists based on the second indication information (PCI of the first cell) and the second auxiliary indication information (information other than the PCI of the first cell). At this time, some cells can be excluded according to the second auxiliary indication information (for example, some cells are excluded according to the parity information of the frequency point), and there is no need to use the algorithm corresponding to each cell in the multiple cells to calculate multiple shortMAC-Is in sequence, thereby improving the computing speed of the candidate base station and improving communication efficiency.

[0271] Optionally, Figure 3 The candidate base stations shown in have the context of the terminal device, i.e. Figure 3 The candidate base station shown in is the first base station. At this time, a terminal device context recovery response message can be sent to the second base station, and the message carries the context of the terminal device.

[0272] Furthermore, after the second base station receives the terminal device context recovery response message sent by the candidate base station (i.e., the first base station), the second base station completes relevant processing according to the context and sends an RRC re-establishment message to the terminal device, which contains the secret key of the target base station. The purpose is to allow future communications between the base station and the UE to be encrypted and integrity protected.

[0273] Optionally, after receiving the RRC re-establishment message, the terminal device stops the relevant timers, restores SRB1, reactivates security, including integrity protection and encryption, and performs measurement processing. The terminal device may then send an RRC re-establishment completion message to the second base station. Upon receipt of this message, the RRC re-establishment process ends.

[0274] Alternatively, if Figure 3 The candidate base station shown in does not have the context of the terminal device, that is, Figure 3 The candidate base station shown in is not the first base station. At this time, a message of failure to restore the terminal device context can be sent to the second base station.

[0275] It can be understood that in the above method embodiments, the steps or operations implemented by the terminal device can be implemented by components that can be configured in the terminal device (such as chips or circuits), and the steps or operations implemented by the access network device (such as the first base station and the second base station) can be implemented by components that can be configured in the access network device (such as chips or circuits).

[0276] Combined with the above Figures 1 to 3 The communication method of the embodiment of the present application is described in detail. Figures 4 to 8 , describe in detail the device of the embodiment of the present application. It should be understood that Figures 4 to 8 The device shown enables Figure 3 To avoid repetition, one or more steps in the method flow shown are not described in detail here.

[0277] Figure 4 4 is a schematic block diagram of a communication device 400 provided in an embodiment of the present application. Figure 4 As shown, the device 400 includes: a processing unit 410 and a transceiver unit 420.

[0278] The processing unit 410 is configured to determine that an RRC connection between the communication device 400 and a first cell fails, where the first cell belongs to a first base station;

[0279] The transceiver unit 420 is used to send a first message to the second base station, where the first message is used to request the re-establishment of the RRC connection. The first message carries first indication information and first auxiliary indication information. The first indication information includes the physical cell identifier PCI of the first cell, and the first auxiliary indication information includes information used to determine the first base station.

[0280] Optionally, the first auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; cell global identifier CGI information of the first cell; and identification information of the first base station.

[0281] Optionally, the first auxiliary indication information occupies one bit, and the one bit is a reserved bit. The first auxiliary indication information indicates attribute information of at least one of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0282] Optionally, the first auxiliary indication information includes indication information of the frequency information of the first cell, including: the first auxiliary indication information includes all or part of the frequency information of the first cell.

[0283] Optionally, the first auxiliary indication information includes indication information of the CGI information of the first cell, including: the first auxiliary indication information includes all or part of the CGI information of the first cell.

[0284] Optionally, the first auxiliary indication information includes indication information of the identification information of the first base station, including: the first auxiliary indication information includes all or part of the identification information of the first base station.

[0285] Optionally, before the transceiver unit 420 sends the first message to the second base station, the transceiver unit 420 is also used to: receive third indication information sent by the second base station, the third indication information is used to indicate whether the second base station supports receiving the first auxiliary indication information; the transceiver unit 420 is specifically used to: when it is determined that the second base station supports receiving the first auxiliary indication information, the transceiver unit 420 sends the first message to the second base station.

[0286] The communication device 400 may correspond to the terminal device in the communication method 300 according to the embodiment of the present application, or a component (chip or circuit) configured in the terminal device. Figure 3 The units of the method executed by the terminal device of the communication method 300. In addition, the units in the communication device 400 and the above-mentioned other operations and / or functions are respectively for implementing Figure 3 The corresponding process of the communication method 300 and the specific process of each unit performing the above corresponding steps have been described in detail in the method 300, and for the sake of brevity, they will not be repeated here.

[0287] The transceiver unit 420 may be a transceiver, or a transceiver circuit, or an interface circuit, or a communication interface, or an input / output circuit.

[0288] The processing unit 410 may include at least one processor or processing circuit.

[0289] Optionally, the communication device 400 may further include a storage unit that can be used to store data and / or code (program). The processing unit 410 and the transceiver unit 420 may be coupled to the storage unit. For example, the processing unit 410 may read the data and / or code (program) to implement the corresponding method. The storage unit may include at least one processor.

[0290] In a possible implementation, the communication device 400 may be a terminal device 50, wherein the function of the processing unit 410 may be implemented by the processor 502 of the terminal device 50, and the function of the sending unit 420 may be implemented by the transceiver 501 (i.e., the control circuit and the antenna together) of the terminal device. Figure 5 The structure of the terminal device of the embodiment of the present application is introduced.

[0291] Figure 5 This is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application. The terminal device can be applied to Figure 1In the system shown, the functions of the terminal device in the above method embodiment are executed. For the convenience of explanation, Figure 5 Only the main components of the terminal device are shown. Figure 5 As shown, the terminal device 50 includes a processor, memory, control circuitry, an antenna, and input / output devices. The processor is primarily used to process communication protocols and communication data, control the entire terminal device, execute software programs, and process software program data, for example, to support the terminal device in performing the actions described in the above method embodiments. The memory is primarily used to store software programs and data. The control circuitry is primarily used to convert baseband signals into radio frequency signals and process radio frequency signals. The control circuitry and antenna together can also be referred to as a transceiver, which is primarily used to transmit and receive radio frequency signals in the form of electromagnetic waves. Input / output devices, such as a touch screen, display, and keyboard, are primarily used to receive user input and output data to the user.

[0292] When a terminal device is powered on, the processor reads the software program from its memory, interprets and executes its instructions, and processes its data. When data needs to be transmitted wirelessly, the processor performs baseband processing on the data to be transmitted and outputs the baseband signal to the RF circuit. The RF circuit then processes the baseband signal and transmits it via the antenna as electromagnetic waves. When data is sent to the terminal device, the RF circuit receives the RF signal via the antenna, converts it into a baseband signal, and outputs the baseband signal to the processor, which converts the baseband signal into data and processes it.

[0293] Those skilled in the art will understand that for ease of explanation, Figure 5 Only one memory and one processor are shown. In an actual terminal device, multiple processors and multiple memories may exist. Memory may also be referred to as a storage medium or storage device. The memory may be a storage element on the same chip as the processor, i.e., an on-chip storage element, or an independent storage element, which is not limited in the embodiments of the present application.

[0294] As an optional implementation, the terminal device may include a baseband processor and a central processing unit. The baseband processor is mainly used to process the communication protocol and communication data, and the central processing unit is mainly used to control the entire terminal device, execute software programs, and process software program data. Figure 5The processor in the can integrate the functions of the baseband processor and the central processing unit. Those skilled in the art will understand that the baseband processor and the central processing unit can also be independent processors that are interconnected through technologies such as buses. Those skilled in the art will understand that the terminal device can include multiple baseband processors to adapt to different network standards, and the terminal device can include multiple central processing units to enhance its processing capabilities. The various components of the terminal device can be connected through various buses. The baseband processor can also be expressed as a baseband processing circuit or a baseband processing chip. The central processing unit can also be expressed as a central processing circuit or a central processing chip. The function of processing communication protocols and communication data can be built into the processor, or it can be stored in the memory in the form of a software program, and the processor executes the software program to implement the baseband processing function.

[0295] In the embodiment of the present application, the antenna and the control circuit with transceiver functions can be regarded as the transceiver unit 501 of the terminal device 50, for example, for supporting the terminal device to perform the receiving function and the sending function. The processor 502 with the processing function can be regarded as the processing unit 502 of the terminal device 50. Figure 5 As shown, the terminal device 50 includes a transceiver unit 501 and a processing unit 502. The transceiver unit may also be referred to as a transceiver, a transceiver, a transceiver device, etc. Optionally, the device in the transceiver unit 501 that implements the receiving function may be considered a receiving unit, and the device in the transceiver unit 501 that implements the transmitting function may be considered a transmitting unit. That is, the transceiver unit 501 includes a receiving unit and a transmitting unit. The receiving unit may also be referred to as a receiver, an input port, a receiving circuit, etc., and the transmitting unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0296] The processor 502 may be configured to execute instructions stored in the memory to control the transceiver unit 501 to receive and / or transmit signals, thereby completing the functions of the terminal device in the above-described method embodiment. The processor 502 also includes an interface for implementing signal input / output functions. As an implementation method, the functions of the transceiver unit 501 may be implemented using a transceiver circuit or a dedicated transceiver chip.

[0297] Figure 6 600 is a schematic block diagram of a communication device 600 provided in an embodiment of the present application. Figure 6 As shown, the device 600 includes: a transceiver unit 610 and a processing unit 620.

[0298] The transceiver unit 610 is configured to receive a first message sent by a terminal device, where the first message is used to request re-establishment of an RRC connection, and the first message carries first indication information and first auxiliary indication information, where the first indication information includes a physical cell identifier (PCI) of a first cell, and the first auxiliary indication information includes information used to determine a first base station, where the first cell is a cell in which the RRC connection of the terminal device fails, and the first cell belongs to the first base station;

[0299] The processing unit 620 is configured to determine at least one candidate base station according to the first indication information and the first auxiliary indication information, where the at least one candidate base station includes the first base station.

[0300] Optionally, the first auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; cell global identifier CGI information of the first cell; and identification information of the first base station.

[0301] Optionally, the first auxiliary indication information occupies one bit, and the one bit is a reserved bit. The first auxiliary indication information indicates attribute information of at least one of the frequency information of the first cell, the CGI information of the first cell, and the identification information of the first base station.

[0302] Optionally, the first auxiliary indication information includes indication information of the frequency information of the first cell, including: the first auxiliary indication information includes all or part of the frequency information of the first cell.

[0303] Optionally, the first auxiliary indication information indicates indication information of the CGI information of the first cell, including: the first auxiliary indication information includes all or part of the CGI information of the first cell.

[0304] Optionally, the first auxiliary indication information indicates indication information of the identification information of the first base station, including: the first auxiliary indication information includes all or part of the identification information of the first base station.

[0305] Optionally, before the transceiver unit 610 receives the first message sent by the terminal device, the transceiver unit 610 is further used to: send third indication information to the terminal device, where the third indication information is used to indicate that the second base station supports receiving the first auxiliary indication information.

[0306] Optionally, the processing unit 620 is further used to: determine a second message based on the first indication information and the first auxiliary indication information, the second message being used to request the context of the terminal device; the transceiver unit 620 is further used to: send the second message to the candidate base station.

[0307] Optionally, the second message carries second indication information and second auxiliary indication information, the second indication information includes the PCI of the first cell, and the second auxiliary indication information includes information used to determine the first cell.

[0308] Optionally, the first auxiliary indication information includes frequency information of the first cell, and the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0309] Optionally, the first auxiliary indication information includes CGI information of the first cell, and the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0310] Specifically, the communication device 600 may correspond to the second base station in the communication method 300 according to the embodiment of the present application, or a chip configured in the second base station. Figure 3 The units of the method performed by the second base station in the communication method 300. In addition, the units in the communication device 600 and the above-mentioned other operations and / or functions are respectively for implementing Figure 3 The corresponding process of the communication method 300 and the specific process of each unit performing the above corresponding steps have been described in detail in the method 300, and for the sake of brevity, they will not be repeated here.

[0311] In a possible implementation, the transceiver unit 610 may be a transceiver, or a transceiver circuit, or an interface circuit, or a communication interface, or an input / output circuit.

[0312] The processing unit 620 may include at least one processor or processing circuit.

[0313] Optionally, the communication device 600 may further include a storage unit that can be used to store data and / or code (program). The processing unit 620 and the transceiver unit 610 may be coupled to the storage unit. For example, the processing unit 620 may read the data and / or code (program) to implement the corresponding method. The storage unit may include at least one processor.

[0314] In a possible implementation, the communication device 600 may be an access network device, such as the base station 80 hereinafter, wherein the function of the transceiver unit 610 may be implemented by the RRU 801 of the base station 80 .

[0315] Figure 7 700 is a schematic block diagram of a communication device 700 provided in an embodiment of the present application. Figure 7 As shown, the device 700 includes: a transceiver unit 710 and a processing unit 720.

[0316] The transceiver unit 710 is used to receive a second message sent by the second base station, where the second message is used to request the context of the terminal device. The second message carries second indication information and second auxiliary indication information. The second indication information includes the physical cell identifier PCI of the first cell. The second auxiliary indication information includes information used to determine the first cell. The first cell is the cell where the RRC connection of the terminal device fails.

[0317] The processing unit 720 is configured to determine whether a context of the terminal device exists according to the second indication information and the second auxiliary indication information.

[0318] Optionally, the second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

[0319] Specifically, the communication device 700 may correspond to the candidate base station in the communication method 300 according to the embodiment of the present application, or a chip configured in the candidate base station. Figure 3 The unit of the method performed by the candidate base station of the communication method 300. In addition, the various units in the communication device 700 and the above-mentioned other operations and / or functions are respectively for implementing Figure 3 The corresponding process of the communication method 300 and the specific process of each unit performing the above corresponding steps have been described in detail in the method 300, and for the sake of brevity, they will not be repeated here.

[0320] In a possible implementation, the transceiver unit 710 may be a transceiver, or a transceiver circuit, or an interface circuit, or a communication interface, or an input / output circuit.

[0321] The processing unit 720 may include at least one processor or processing circuit.

[0322] Optionally, the communication device 700 may further include a storage unit that can be used to store data and / or code (program). The processing unit 720 and the transceiver unit 710 may be coupled to the storage unit. For example, the processing unit 720 may read the data and / or code (program) to implement the corresponding method. The storage unit may include at least one processor.

[0323] In a possible implementation, the communication device 700 may be an access network device, such as the base station 80 mentioned below, wherein the function of the transceiver unit 710 may be implemented by the RRU 801 of the base station 80. Figure 8 The structure of the access network device of the embodiment of the present application is introduced.

[0324] Figure 8 This is a schematic diagram of the structure of an access network device in an embodiment of the present application, such as a schematic diagram of the structure of a base station. Figure 8 As shown, the base station can be applied to Figure 1 In the system shown, the functions of the access network device in the above-mentioned method embodiment are performed. The base station 80 may include one or more radio frequency units, such as a remote radio unit (RRU) 801 and one or more baseband units (BBU) (also referred to as digital units, DU) 802. The RRU 801 may be referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., and may include at least one antenna 8011 and a radio frequency unit 8012. The RRU 801 part is mainly used for receiving and transmitting radio frequency signals and converting radio frequency signals into baseband signals, for example, for sending the signaling messages described in the above-mentioned embodiment to the terminal device. The BBU 802 part is mainly used for baseband processing, controlling the base station, etc. The RRU 801 and BBU 802 may be physically arranged together or physically separated, that is, a distributed base station.

[0325] The BBU 802 is the control center of the base station, which can also be called a processing unit. It is mainly used to perform baseband processing functions such as channel coding, multiplexing, modulation, spread spectrum, etc. For example, the BBU (processing unit) 802 can be used to control the base station to execute the operation process of the network device in the above method embodiment.

[0326] In one example, the BBU 802 may be composed of one or more boards, and the multiple boards may jointly support a wireless access network with a single access indication (such as an LTE network), or may respectively support wireless access networks with different access standards (such as an LTE network, a 5G network, or other networks). The BBU 802 also includes a memory 8021 and a processor 8022, and the memory 8021 is used to store necessary instructions and data. For example, the memory 8021 stores the correspondence between the codebook index and the precoding matrix in the above embodiment. The processor 8022 is used to control the base station to perform necessary actions, such as controlling the base station to execute the operation process of the network device in the above method embodiment. The memory 8021 and the processor 8022 may serve one or more boards. That is, a memory and a processor may be separately set on each board. Alternatively, multiple boards may share the same memory and processor. In addition, necessary circuits may be provided on each board.

[0327] It should be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0328] It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0329] According to the method provided in the embodiment of the present application, the present application also provides a computer program product, which includes: a computer program code, which, when executed on a computer, causes the computer to execute Figure 3 A method according to any one of the embodiments shown.

[0330] According to the method provided in the embodiment of the present application, the present application also provides a computer-readable medium, which stores a program code, and when the program code is run on a computer, the computer executes Figure 3 A method according to any one of the embodiments shown.

[0331] According to the method provided in the embodiment of the present application, the present application also provides a system, which includes the aforementioned one or more terminal devices and one or more access network devices.

[0332] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0333] For ease of understanding, the terms involved in the process of introducing the solution of this application are explained below.

[0334] In the embodiment of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the "indication information" in the foregoing text) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein the other information has an association relationship with the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can also be achieved by means of the arrangement order of each information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent.

[0335] In the embodiments of the present application, various terms and abbreviations, such as radio resource control (RRC), physical cell identity (PCI), cell radio network temporary identity (c-RNTI), short MAC-I, cell global identity (CGI), system information block (SIB), etc., are illustrative examples given for the convenience of description and should not constitute any limitation to the present application. The present application does not exclude the possibility of defining other terms that can achieve the same or similar functions in existing or future protocols.

[0336] In the embodiments of the present application, “first”, “second” and various numbers are only used for the convenience of description and are not intended to limit the scope of the embodiments of the present application. For example, different indication information can be distinguished.

[0337] The “communication protocol” involved in the embodiments of the present application may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, a NR protocol, and related protocols used in future communication systems, and the present application does not limit this.

[0338] The term "and / or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. Additionally, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0339] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0340] In various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0341] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0342] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0343] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0344] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0345] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0346] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

Claims

1. A communication method, characterized in that: include: Determining that a radio resource control (RRC) connection with a first cell fails, wherein the first cell belongs to a first base station; Sending a first message to the second base station, where the first message is used to request re-establishing an RRC connection, the first message carrying first indication information and first auxiliary indication information, the first indication information including a physical cell identifier (PCI) of the first cell, and the first auxiliary indication information including information used to identify the first base station; The first auxiliary indication information occupies one bit, and the one bit is a reserved bit. The first auxiliary indication information indicates that the frequency of the first cell and the last digits of the cell global identifier CGI of the first cell are both odd numbers or both are even numbers.

2. The method according to claim 1, characterized in that Before sending the first message to the second base station, the method further includes: receiving third indication information from the second base station, where the third indication information is used to indicate whether the second base station supports receiving the first auxiliary indication information; The sending the first message to the second base station includes: In a case where it is determined that the second base station supports receiving the first auxiliary indication information, the first message is sent to the second base station.

3. A communication method, characterized in that: include: receiving a first message from a terminal device, where the first message is used to request re-establishing an RRC connection, the first message carrying first indication information and first auxiliary indication information, the first indication information including a physical cell identifier (PCI) of a first cell, the first auxiliary indication information including information used to determine a first base station, the first auxiliary indication information occupying one bit, and the one bit being a reserved bit, the first auxiliary indication information indicating that the frequency of the first cell and the last digit of the CGI of the first cell are both odd numbers or both even numbers, wherein the first cell is a cell in which the RRC connection of the terminal device fails, and the first cell belongs to the first base station; At least one candidate base station is determined according to the first indication information and the first auxiliary indication information, where the at least one candidate base station includes the first base station.

4. The method according to claim 3, characterized in that Before receiving the first message from the terminal device, the method further includes: Send third indication information to the terminal device, where the third indication information is used to indicate support for receiving the first auxiliary indication information.

5. The method according to claim 3 or 4, characterized in that The method further comprises: determining a second message according to the first indication information and the first auxiliary indication information, where the second message is used to request a context of the terminal device; Sending the second message to the candidate base station.

6. The method according to claim 5, characterized in that The second message carries second indication information and second auxiliary indication information, the second indication information includes the PCI of the first cell, and the second auxiliary indication information includes information used to determine the first cell.

7. The method according to claim 6, characterized in that The second auxiliary indication information includes indication information of at least one of the following information: frequency information of the first cell; CGI information of the first cell.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is run on a computer, the computer is caused to execute the method according to any one of claims 1 to 7.

9. A communication device, characterized in that: The method comprises units or modules for implementing the method according to claim 1 or 2.

10. A communication device, characterized in that: The method comprises units or modules for implementing the method according to any one of claims 3 to 7.

11. A communication system, characterized in that: Comprising at least one of the communication devices according to claims 9 and 10.

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