Communication method and device

Abstract

The embodiment of the invention discloses a communication method and device, relates to the technical field of communication, and can enable input parameters of corresponding PDCP (Packet Data Convergence Protocol) entities of a first terminal and a second terminal to be consistent when executing a security algorithm, ensure normal communication of a side link SL and improve the communication reliability. The specific scheme is as follows: a first terminal determines a logical channel identifier (LCID) meeting a preset condition; a first packet data convergence protocol PDCP entity of the first terminal is associated with two or more logical channels LCHs; the first terminal receives a first data packet from the second terminal; and the first PDCP entity of the first terminal analyzes the first data packet based on the LCID.

Description

[0001] This application is a divisional application. The application number of the original application is 201980103097.X, the original application date is December 31, 2019, and the entire content of the original application is incorporated herein by reference. Technical Field

[0002] Embodiments of this application relate to the field of communication technologies, and in particular, to a communication method and apparatus. Background Art

[0003] Vehicle to everything (V2X) refers to the interconnection between a vehicle and the outside world through devices configured on the vehicle and various communication technologies, such as interconnection communication between vehicle and vehicle, vehicle and person, vehicle and roadside infrastructure, vehicle and network, etc. The direct communication link between V2X user equipment (UE) is a sidelink (SL), and the direct communication interface between V2X UEs is the V2X PC5 interface.

[0004] In long term evolution (LTE) V2X, before device to device (D2D) performs unicast communication, PC5 interface signaling (PC5-S) connection establishment and security establishment need to be carried out. After the PC5-S connection establishment and security establishment are completed, subsequent user plane data transmission of the corresponding access stratum (AS) can be based on the security algorithm negotiated by UE1 and UE2 during the PC5-S connection establishment, and the logical channel identifier (LCID) is used as the bearer parameter in the input parameters of the AS layer security algorithm. To improve the reliability of service transmission, packet data convergence protocol (PDCP) duplication can be introduced, that is, one PDCP entity is associated with multiple logical channels (LCH). Then, when the corresponding PDCP entities of the sending UE and the receiving UE execute the security algorithm, different LCIDs may be used as the input parameters of the security algorithm, which will cause the receiving UE to be unable to correctly parse the data packets sent by the sending UE, resulting in abnormal communication of the SL between the sending UE and the receiving UE. Summary of the Invention

[0005] The embodiments of the present application provide a communication method and apparatus, which can make the input parameters of the corresponding PDCP entities of the first terminal and the second terminal consistent when executing the security algorithm, ensure the normal communication of the sidelink, and improve the reliability of communication.

[0006] To achieve the above object, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect of the embodiments of the present application, a communication method is provided. The method includes: the first terminal determines a logical channel identifier (LCID) that meets a preset condition; the first packet data convergence protocol (PDCP) entity of the first terminal is associated with two or more logical channels (LCHs); the first terminal receives a first data packet from the second terminal; the above-mentioned first PDCP entity of the first terminal parses the first data packet based on the LCID. Based on this solution, the first terminal determines the LCID that meets the preset condition, and after receiving the first data packet, parses the data packet sent by the second terminal based on the LCID that meets the preset condition. Therefore, after receiving the data packet, the first terminal does not randomly parse the data packet sent by the second terminal based on an LCID. Instead, it parses the data packet sent by the second terminal based on the LCID that meets the preset condition. It can be understood that the LCID determined by the first terminal that meets the preset condition is the same as the LCID when the second terminal performs security protection on the first data packet. Therefore, it can be ensured that the first terminal can normally parse the first data packet based on the LCID that meets the preset condition, so that the sidelink between the first terminal and the second terminal can communicate normally. That is, this solution can ensure the consistency of the input parameters of the corresponding PDCP entities of the first terminal and the second terminal when executing the security algorithm, and enable the sidelink between the transceiver UEs to communicate normally.

[0008] Optionally, the first terminal may determine the LCID that meets the preset condition based on the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal.

[0009] Combined with the first aspect, in a possible implementation manner, the first data packet is a data packet after the second PDCP entity of the second terminal performs security protection based on the LCID that meets the preset condition, and the second PDCP entity of the second terminal corresponds to the first PDCP entity of the first terminal. Based on this solution, it can be ensured that the LCID when the second terminal performs security protection on the first data packet is the same as the LCID when the first terminal parses the first data packet, so that the sidelink between the first terminal and the second terminal can communicate normally.

[0010] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above preset condition includes a first preset condition, and the size of the above LCID meets this first preset condition. Based on this solution, the LCID determined by the first terminal that meets the preset condition can be an LCID whose size meets the first preset condition. Exemplarily, the LCID determined by the first terminal that meets the preset condition can be the largest LCID, or the smallest LCID, or the second largest LCID, or the second smallest LCID, etc. among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal. The present application embodiment does not limit the specific content of the first preset condition.

[0011] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above first terminal determines a logical channel identifier LCID that meets the preset condition, including: the above first terminal determines an LCID that meets the above first preset condition based on a preset rule, and this preset rule is predefined. Based on this solution, the first terminal can determine an LCID whose size meets the first preset condition based on the predefined rule. Exemplarily, the above preset rule can be stipulated by the protocol, that is, the first terminal can determine an LCID that meets the first preset condition based on the rule stipulated by the protocol. For example, if the protocol stipulates that the largest LCID among the LCIDs corresponding to the LCHs associated with PDCP is used as the input parameter of the security algorithm of this PDCP entity, then the first terminal can, based on this rule, determine the largest LCID among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal as the LCID that meets the first preset condition.

[0012] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above method further includes: the above first terminal receives first indication information from the second terminal, and this first indication information is used to instruct the above first terminal to use the LCID that meets the above first preset condition as the input parameter of the security algorithm of the above first PDCP entity. Based on this solution, the first terminal can also receive the indication information sent by the second terminal, so that the first terminal can determine the LCID that meets the first preset condition based on the indication information of the second terminal. It should be noted that the indication granularity of the first indication information can be all PDCP entities of the first terminal, or a certain PDCP entity of the first terminal.

[0013] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above first terminal determines a logical channel identifier LCID that meets a preset condition, including: the above first terminal determines, based on the above first indication information, an LCID that meets the above first preset condition. Based on this solution, the first terminal can determine, based on the indication information of the second terminal, an LCID that meets the first preset condition, so that the LCID determined by the first terminal that meets the first preset condition is the same as the LCID when the second terminal performs security protection on the first data packet. Therefore, it can be ensured that the first terminal can normally parse the first data packet based on the LCID that meets the preset condition, so that the SL between the first terminal and the second terminal can communicate normally. Optionally, the above first indication information may further include the LCID determined by the second terminal that meets the first preset condition, and the first indication information is specifically used to instruct the first terminal to use the LCID determined by the second terminal that meets the first preset condition as the input parameter of the security algorithm of the above first PDCP entity.

[0014] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above first indication information is carried in the first sidelink radio bearer SLRB configuration information, and the first SLRB configuration information is carried in the PC5-radio resource control RRC message. Based on this solution, when the first indication information is carried in the first SLRB configuration information, the first indication information indicates that the PDCP entity corresponding to the SLRB configuration uses the LCID that meets the above first preset condition as the input parameter of the security algorithm of the PDCP entity, so that the granularity indicated by the first indication information is a certain PDCP entity. Optionally, the above first indication information may also be sent separately from the first SLRB configuration information.

[0015] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above LCID that meets the above first preset condition is the smallest LCID or the largest LCID among the LCIDs corresponding to the above two or more logical channel headers LCHs. Based on this solution, the first terminal can determine the smallest LCID or the largest LCID among the LCIDs corresponding to the two or more LCHs associated with the first PDCP entity as the above LCID that meets the first preset condition. Optionally, the first terminal may also determine the second smallest LCID or the second largest LCID among the LCIDs corresponding to the two or more LCHs associated with the first PDCP entity as the above LCID that meets the first preset condition, etc., and the present application does not limit this.

[0016] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above preset condition includes a second preset condition, and the LCH configuration parameter corresponding to the above LCID conforms to the second preset condition. Based on this solution, the LCID determined by the first terminal that meets the preset condition can be the LCID corresponding to the LCH whose LCH configuration parameter corresponding to the LCID conforms to the second preset condition. Exemplarily, the LCID determined by the first terminal that meets the preset condition can be the LCID corresponding to the LCH with the highest priority among two or more LCHs associated with the first PDCP entity of the first terminal, or it can also be the LCID corresponding to other LCHs whose LCH configuration parameters meet the second preset condition. The embodiments of the present application do not limit the specific content of the second preset condition.

[0017] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above method further includes: the first terminal receives second indication information from the second terminal, the second indication information includes a target LCID, and the second indication information is used to instruct the first terminal to use the target LCID as an input parameter of the security algorithm of the first PDCP entity, and the target LCID is the LCID corresponding to the LCH determined by the second terminal that meets the second preset condition. Based on this solution, the first terminal can receive the second indication information sent by the second terminal, so that the first terminal determines the LCID that meets the second preset condition based on the second indication information.

[0018] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the first terminal determines a logical channel identifier LCID that meets the preset condition, including: the first terminal determines the LCID that meets the second preset condition based on the second indication information. Based on this solution, the first terminal can use the LCID corresponding to the LCH determined by the second terminal that meets the second preset condition as an input parameter of the security algorithm of the first PDCP entity of the first terminal based on the second indication information sent by the second terminal, so as to ensure that the input parameters of the corresponding PDCP entities of the first terminal and the second terminal are consistent when executing the security algorithm, and enable the SL between the first terminal and the second terminal to communicate normally.

[0019] Combined with the first aspect and the above possible implementation manners, in another possible implementation manner, the above second indication information is carried in the second SLRB configuration information, and the second SLRB configuration information is carried in the PC5-RRC message. Based on this solution, when the second indication information is carried in the second SLRB configuration information, the second indication information indicates that the PDCP entity corresponding to the SLRB configuration information uses the LCID that meets the above second preset condition as the input parameter of the security algorithm of the PDCP entity, so that the granularity indicated by the second indication information is a certain PDCP entity. Optionally, the above second indication information may also be sent separately from the second SLRB configuration information.

[0020] In a second aspect of the embodiments of the present application, a communication method is provided. The method includes: a second terminal determines a logical channel identifier (LCID) that meets a preset condition; a second packet data convergence protocol (PDCP) entity of the second terminal is associated with two or more logical channels (LCHs); the second terminal uses the LCID as the input parameter of the security algorithm of the second PDCP entity to perform security protection on a first data packet; the second terminal sends the first data packet after security protection to a first terminal; wherein the LCID is the input parameter when a first PDCP entity of the first terminal parses the first data packet, and the first PDCP entity of the first terminal corresponds to the second PDCP entity of the second terminal. Based on this solution, by the second terminal determining the LCID that meets the preset condition and using the LCID as the input parameter of the security algorithm of the second PDCP entity of the second terminal to perform security protection on the first data packet, and the LCID is the input parameter when the first PDCP entity of the first terminal parses the first data packet, therefore, this solution can ensure that the input parameters of the corresponding PDCP entities of the first terminal and the second terminal are consistent when performing the security algorithm, so that the SL between the first terminal and the second terminal can communicate normally.

[0021] Combined with the second aspect, in a possible implementation manner, the above preset condition includes a first preset condition, and the size of the LCID meets the first preset condition. Based on this solution, the LCID determined by the second terminal that meets the preset condition can be an LCID whose size meets the first preset condition.

[0022] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, when the second terminal determines a logical channel identifier (LCID) that meets a preset condition, it includes: the second terminal determines, based on a preset rule, an LCID that meets the first preset condition, and the preset rule is predefined. Based on this solution, the first terminal can determine, based on the predefined rule, an LCID whose size meets the first preset condition. Exemplarily, the above preset rule may be specified by a protocol.

[0023] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the second terminal determines a logical channel identifier LCID that meets a preset condition, including: the second terminal determines the LCID that meets the first preset condition based on the sizes of the LCIDs corresponding to the two or more LCHs. Based on this solution, the second terminal can also determine, based on the sizes of the LCIDs corresponding to the two or more LCHs associated with the second PDCP entity, the LCID that serves as an input parameter of the security algorithm of the second PDCP entity.

[0024] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the method further includes: the second terminal receives third indication information from a network device, and the third indication information is used to instruct the second terminal to use the LCID that meets the first preset condition as an input parameter of the security algorithm of the second PDCP entity. Based on this solution, the second terminal can receive the third indication information from the network device, so that the second terminal determines the LCID that meets the first preset condition according to the indication of the network device. For example, the network device instructs the second terminal to use the largest or smallest LCID as the input parameter of the security algorithm of the second PDCP entity.

[0025] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the second terminal determines a logical channel identifier LCID that meets a preset condition, including: the second terminal determines the LCID that meets the first preset condition based on the third indication information. Based on this solution, the second terminal determines the LCID that meets the first preset condition based on the third indication information of the network device. For example, the second terminal can determine, based on the third indication information of the network device, that the largest or smallest LCID is the LCID that meets the first preset condition.

[0026] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the third indication information further includes the identifier information of the first terminal. Based on this solution, the network device can instruct the second terminal to use the LCID that meets the first preset condition within the unicast connection communication between the first terminal and the second terminal as the input parameter of the security algorithm of the first PDCP entity.

[0027] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the above third indication information is carried in the third sidelink radio bearer (SLRB) configuration information, and the third SLRB configuration information is carried in a radio resource control (RRC) message, a system information block (SIB), or a preconfigured message. Based on this solution, the third indication information sent by the network device can be carried in the RRC message, the SIB, or the preconfigured message. In this solution, the above third indication information specifically indicates that the PDCP entity corresponding to the SLRB configuration information uses the LCID that meets the above first preset condition as the input parameter of the security algorithm of this PDCP entity, so that the granularity indicated by the third indication information is a certain PDCP entity. Optionally, the above third indication information may also be sent separately from the third SLRB configuration information.

[0028] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the above method further includes: the above second terminal sends first indication information to the above first terminal, and the first indication information is used to indicate that the above first terminal uses the LCID that meets the above first preset condition as the input parameter of the security algorithm of the first PDCP entity of the above first terminal. Based on this solution, the second terminal can send the first indication information to the first terminal to indicate that the first terminal uses one LCID among multiple LCIDs as the input parameter of the security algorithm of the first PDCP entity of the first terminal, so as to ensure that the input parameters of the corresponding PDCP entities of the first terminal and the second terminal are consistent when executing the security algorithm.

[0029] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the above first indication information is carried in the first sidelink radio bearer (SLRB) configuration information, and the first SLRB configuration information is carried in the PC5-RRC message. Based on this solution, when the first indication information is carried in the first SLRB configuration information, the first indication information indicates that the PDCP entity corresponding to the SLRB configuration uses the LCID that meets the above first preset condition as the input parameter of the security algorithm of this PDCP entity, so that the granularity indicated by the first indication information is a certain PDCP entity. Optionally, the above first indication information may also be sent separately from the first SLRB configuration information.

[0030] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the LCID that meets the above first preset condition is the smallest LCID or the largest LCID among the LCIDs corresponding to the two or more LCHs. Based on this solution, the second terminal may determine the smallest LCID or the largest LCID among the LCIDs corresponding to the two or more LCHs associated with the second PDCP entity as the LCID that meets the first preset condition. Optionally, the second terminal may also determine the second smallest LCID or the second largest LCID among the LCIDs corresponding to the two or more LCHs associated with the second PDCP entity as the LCID that meets the first preset condition, and so on. This application does not limit this.

[0031] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the preset condition includes a second preset condition, and the LCH configuration parameter corresponding to the LCID meets this second preset condition. Based on this solution, the LCID determined by the second terminal that meets the preset condition may be the LCID whose LCH configuration parameter corresponding to the LCID meets the second preset condition.

[0032] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the second terminal determines the logical channel identifier LCID that meets the preset condition, including: the second terminal determines the LCID that meets the second preset condition based on the LCH configuration parameters of the two or more LCHs. Based on this solution, the second terminal may autonomously determine the LCID that is an input parameter of the security algorithm of the second PDCP entity based on the LCH configuration parameters of the two or more LCHs associated with the second PDCP entity. For example, the second terminal may determine to use the LCID corresponding to the LCH with the highest priority as the input parameter of the security algorithm of the second PDCP entity based on the LCH configuration parameters of the two or more LCHs associated with the second PDCP entity.

[0033] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the above method further includes: the above second terminal receives fourth indication information from a network device, where the fourth indication information includes target LCH configuration parameters, and the fourth indication information is used to instruct the above second terminal to use an LCID that meets the above second preset condition as an input parameter of the security algorithm of the above second PDCP entity, and the LCID that meets the above second preset condition is the LCID corresponding to the above target LCH configuration parameter. Based on this solution, the second terminal can receive the fourth indication information from the network device, so that the second terminal determines the LCID that meets the second preset condition according to the indication of the network device. For example, the network device instructs the second terminal to use the LCID corresponding to the LCH with the highest priority as the input parameter of the security algorithm of the above second PDCP entity. Alternatively, the network device instructs the second terminal to use the LCID corresponding to the LCH associated with the configuration grant type CG as the input parameter of the security algorithm of the above second PDCP entity.

[0034] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the above second terminal determines a logical channel identifier LCID that meets a preset condition, including: the above second terminal determines the LCID that meets the above second preset condition based on the above fourth indication information. Based on this solution, the second terminal determines the LCID that meets the second preset condition based on the fourth indication information of the network device. For example, the second terminal can determine, based on the fourth indication information of the network device, that the LCID corresponding to the LCH with the highest priority is the LCID that meets the second preset condition.

[0035] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the above fourth indication information is carried in fourth SLRB configuration information, and the fourth SLRB configuration information is carried in an RRC message, a system information block SIB, or a preconfigured message. Based on this solution, when the fourth indication information is carried in the fourth SLRB configuration information, the fourth indication information sent by the network device specifically instructs the second terminal to use the LCID that meets the above second preset condition as the input parameter of the security algorithm of the PDCP entity corresponding to the fourth SLRB configuration information, so that the granularity indicated by the fourth indication information is a certain PDCP entity. Optionally, the above fourth indication information may also be sent separately from the fourth SLRB configuration information.

[0036] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the above method further includes: the second terminal sends second indication information to the first terminal, where the second indication information includes a target LCID, and the second indication information is used to instruct the first terminal to use the target LCID as an input parameter of a security algorithm of a first PDCP entity of the first terminal, and the target LCID is an LCID corresponding to an LCH that meets the second preset condition determined by the second terminal. Based on this solution, the second terminal can send the second indication information to the first terminal to instruct the first terminal to use one LCID among multiple LCIDs as an input parameter of the security algorithm of the first PDCP entity of the first terminal, so as to ensure that the input parameters of the corresponding PDCP entities of the first terminal and the second terminal are consistent when performing the security algorithm.

[0037] Combined with the second aspect and the above possible implementation manners, in another possible implementation manner, the second indication information is carried in second SLRB configuration information, and the second SLRB configuration information is carried in a PC5-RRC message. Based on this solution, when the second indication information is carried in the second SLRB configuration information, the second indication information instructs the PDCP entity corresponding to the SLRB configuration information to use the LCID that meets the second preset condition as an input parameter of the security algorithm of the PDCP entity, so that the granularity indicated by the second indication information is a certain PDCP entity. Optionally, the second indication information may also be sent separately from the second SLRB configuration information.

[0038] In a third aspect of the embodiments of the present application, a communication method is provided. The method includes: a network device determines a preset condition; the network device sends indication information to a second terminal, where the indication information is used to instruct the second terminal to use a logical channel identifier (LCID) that meets the preset condition as an input parameter of a security algorithm of a second packet data convergence protocol (PDCP) entity of the second terminal, and the second PDCP entity of the second terminal is associated with two or more logical channels (LCHs). Based on this solution, the network device can determine the content of the preset condition and send indication information to the second terminal to instruct the second terminal to use the LCID that meets the preset condition as an input parameter of the security algorithm of the second PDCP entity of the second terminal. It can be understood that in this solution, the transmitting UE can determine the LCID used as the input parameter of the security algorithm of the PDCP entity of the transmitting UE based on the indication of the network device. Exemplarily, the network device may be an access network device or a core network device.

[0039] In combination with the third aspect, in a possible implementation manner, the above preset condition includes a first preset condition, and the size of the above LCID meets the above first preset condition; the above indication information includes third indication information, and this third indication information is used to instruct the above second terminal to use the LCID that meets the above first preset condition as the input parameter of the security algorithm of the second PDCP entity of the above second terminal. Based on this solution, the network device can determine the content of the first preset condition based on the size of the LCID.

[0040] In combination with the third aspect and the above possible implementation manner, in another possible implementation manner, the above preset condition includes a second preset condition, and the configuration parameters of the LCH corresponding to the above LCID meet the above second preset condition; the above indication information includes fourth indication information, and this fourth indication information is used to instruct the above second terminal to use the LCID that meets the above second preset condition as the input parameter of the security algorithm of the second PDCP entity of the above second terminal. Based on this solution, the network device can determine the content of the second preset condition based on the LCH configuration parameters.

[0041] In combination with the third aspect and the above possible implementation manner, in another possible implementation manner, the above fourth indication information further includes target LCH configuration parameters, and the LCID that meets the above second preset condition is the LCID corresponding to the above target LCH configuration parameters. Based on this solution, the network device can also send the target LCH configuration parameters to the second terminal, so that the second terminal determines the LCID corresponding to the above target LCH configuration parameters as the input parameter of the security algorithm of the second PDCP entity of the second terminal.

[0042] In combination with the third aspect and the above possible implementation manner, in another possible implementation manner, the above indication information is carried in the sidelink radio bearer SLRB configuration information, and this SLRB configuration information is carried in the radio resource control RRC message, the system information block SIB or the preconfigured message. Based on this solution, the indication information sent by the network device is carried in the SLRB configuration information, and this indication information can be the above third indication information or fourth indication information. In this solution, the network device can instruct the PDCP entity corresponding to the SLRB configuration information to use the LCID that meets the above preset condition as the input parameter of the security algorithm of the PDCP entity, so that the granularity indicated by the indication information is a certain PDCP entity. Optionally, the above indication information can also be sent separately from the SLRB configuration information.

[0043] In the fourth aspect of the embodiments of the present application, a communication method is provided. The method includes: The second terminal uses the identifier SLRB ID of the first sidelink radio bearer as an input parameter of the security algorithm to perform security protection on the first data packet; The second terminal sends the first data packet after security protection to the first terminal, and the first SLRB ID is carried in the first data packet. Based on this solution, the first terminal uses the first SLRB ID as an input parameter of the security algorithm to perform security protection on the first data packet, and sends the first data packet carrying the first SLRB ID to the second terminal, so that after receiving the first data packet, the second terminal can parse the first data packet based on the first SLRB ID carried in the first data packet. Therefore, the first terminal and the second terminal can use the same SLRB ID as the input parameter to ensure that the data transmission on the SL between the first terminal and the second terminal can be protected by the security algorithm.

[0044] In the fifth aspect of the embodiments of the present application, a communication method is provided. The method includes: The first terminal receives a first data packet from the second terminal, and the first SLRB ID is carried in the first data packet; The first terminal parses the first data packet based on the first SLRB ID. Based on this solution, the second terminal can parse the first data packet sent by the first terminal based on the first SLRB ID carried in the first data packet, so that the second terminal can normally parse the first data packet, ensuring that the data transmission on the SL between the first terminal and the second terminal can be protected by the security algorithm. It can be understood that the first data packet received by the first terminal from the second terminal is the data packet after the second terminal performs security protection based on the first SLRB ID.

[0045] Combined with the fourth aspect or the fifth aspect, in a possible implementation manner, the first SLRB ID is carried in the header of the first data packet. Based on this solution, by carrying the first SLRB ID in the header of the first data packet, after receiving the first data packet, the first terminal can parse the first data packet based on the first SLRB ID carried in the header of the first data packet, so that the first terminal can know the first SLRB ID when the first data packet is protected during receiving the first data packet. Therefore, the first terminal can normally parse the first data packet, ensuring that the data transmission on the SL between the first terminal and the second terminal can be protected by the security algorithm. For example, the first SLRB ID can be carried in the PDCP header of the first data packet.

[0046] In the sixth aspect of the embodiments of the present application, a communication method is provided. The method includes: a second terminal sends a first message to a first terminal, and the first message carries an identifier SLRB ID of a first sidelink radio bearer; the second terminal receives a second message from the first terminal, and the second message is a message after the first terminal performs security protection based on the first SLRB ID; the second terminal parses the second message based on the first SLRB ID. Based on this solution, by the second terminal sending the first SLRB ID to the first terminal in advance, the first terminal can perform security protection on the second message based on the first SLRB ID, ensuring that the input parameters for the second terminal to perform security protection on the second message are consistent with the input parameters for the first terminal to parse the second message. Therefore, the transmission on the SL between the second terminal and the first terminal can achieve the protection of the security algorithm.

[0047] Optionally, after the second terminal sends a first message carrying the first SLRB ID to the first terminal, the second terminal can also perform security protection on the second message based on the first SLRB and send the second message after security protection to the first terminal. Based on this solution, after the first terminal receives the second message after security protection, the first terminal can perform security parsing on the second message based on the first SLRB carried in the first message.

[0048] In the seventh aspect of the embodiments of the present application, a communication method is provided. The method includes: a first terminal receives a first message from a second terminal, and the first message carries an identifier SLRB ID of a first sidelink radio bearer; the first terminal performs security protection on the second message based on the first SLRB ID; the first terminal sends the second message after security protection to the second terminal. Based on this solution, by the first terminal receiving the first SLRB ID from the first terminal and performing security protection on the second message based on the first SLRB ID, ensuring that the input parameters for the second terminal to perform security protection on the second message are consistent with the input parameters for the first terminal to parse the second message. Therefore, the transmission on the SL between the second terminal and the first terminal can achieve the protection of the security algorithm.

[0049] Optionally, after the first terminal receives a first message carrying the first SLRB ID from the second terminal, the first terminal can also receive the second message after security protection from the second terminal, and the first terminal can perform security parsing on the second message after security protection based on the first SLRB carried in the first message. The second message after security protection is a message after the second terminal performs security protection on the second message based on the first SLRB ID.

[0050] Combined with the sixth aspect or the seventh aspect, in a possible implementation, the first message is a PC5-S message, and the second message is a PC5-S message or a PC5-RRC message. Based on this solution, the second message can be a PC5-S message or a PC5-RRC message after the first message, so that by sending the SLRB ID carrying the second message to the first terminal in advance, the first terminal can perform security protection or security parsing on the second message based on the SLRB ID.

[0051] An eighth aspect of the embodiments of the present application provides a communication device, which includes: a processing unit, configured to determine a logical channel identifier (LCID) that meets a preset condition; the first packet data convergence protocol (PDCP) entity of the device is associated with two or more logical channels (LCHs); a transceiver unit, configured to receive a first data packet from a second terminal; the above-mentioned processing unit is further configured to parse the first data packet based on the LCID.

[0052] Optionally, the above-mentioned processing unit is specifically configured to determine the LCID that meets the preset condition based on the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the device.

[0053] Combined with the eighth aspect, in a possible implementation, the above-mentioned first data packet is a data packet after security protection by the second PDCP entity of the second terminal based on the LCID that meets the preset condition, and the second PDCP entity of the second terminal corresponds to the first PDCP entity of the above-mentioned device.

[0054] Combined with the eighth aspect, in a possible implementation, the above-mentioned preset condition includes a first preset condition, and the size of the LCID meets the first preset condition.

[0055] Combined with the eighth aspect and the above possible implementation, in another possible implementation, the above-mentioned processing unit is specifically configured to determine the LCID that meets the first preset condition based on a preset rule, and the preset rule is predefined.

[0056] Combined with the eighth aspect and the above possible implementation, in another possible implementation, the above-mentioned transceiver unit is further configured to receive first indication information from the second terminal, and the first indication information is used to instruct the above-mentioned device to use the LCID that meets the first preset condition as an input parameter of the security algorithm of the first PDCP entity.

[0057] Combined with the eighth aspect and the above possible implementation, in another possible implementation, the above-mentioned processing unit is specifically configured to determine the LCID that meets the first preset condition based on the first indication information.

[0058] Combined with the eighth aspect and the above possible implementation manners, in another possible implementation manner, the above first indication information is carried in the first sidelink radio bearer (SLRB) configuration information, and the first SLRB configuration information is carried in the PC5 - radio resource control (RRC) message.

[0059] Combined with the eighth aspect and the above possible implementation manners, in another possible implementation manner, the LCID that meets the above first preset condition is the smallest LCID or the largest LCID among the LCIDs corresponding to the above two or more logical channels (LCHs).

[0060] Combined with the eighth aspect and the above possible implementation manners, in another possible implementation manner, the above preset condition includes a second preset condition, and the configuration parameters of the LCH corresponding to the LCID meet the second preset condition.

[0061] Combined with the eighth aspect and the above possible implementation manners, in another possible implementation manner, the above transceiver unit is further configured to receive second indication information from the above second terminal, where the second indication information includes a target LCID, and the second indication information is used to instruct the above device to use the target LCID as an input parameter of the security algorithm of the above first packet data convergence protocol (PDCP) entity, and the target LCID is the LCID corresponding to the LCH determined by the above second terminal and meeting the second preset condition.

[0062] Combined with the eighth aspect and the above possible implementation manners, in another possible implementation manner, the above processing unit is specifically further configured to determine the LCID that meets the second preset condition based on the second indication information.

[0063] Combined with the eighth aspect and the above possible implementation manners, in another possible implementation manner, the above second indication information is carried in the second SLRB configuration information, and the second SLRB configuration information is carried in the PC5 - RRC message.

[0064] In a ninth aspect of the embodiments of the present application, a communication device is provided, and the device includes: a processing unit, configured to determine a logical channel identifier (LCID) that meets a preset condition; the second packet data convergence protocol (PDCP) entity of the device is associated with two or more logical channels (LCHs); the above processing unit is further configured to use the LCID as an input parameter of the security algorithm of the above second PDCP entity to perform security protection on a first data packet; a transceiver unit, configured to send the security - protected first data packet to a first terminal; where the LCID is an input parameter when the first PDCP entity of the first terminal parses the first data packet, and the first PDCP entity of the first terminal corresponds to the second PDCP entity of the above device.

[0065] In combination with the ninth aspect, in a possible implementation, the above-mentioned preset condition includes a first preset condition, and the size of the above-mentioned LCID meets the above-mentioned first preset condition.

[0066] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned processing unit is specifically configured to determine, based on a preset rule, an LCID that meets the above-mentioned first preset condition, and the preset rule is predefined.

[0067] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned processing unit is specifically further configured to determine, based on the sizes of the LCIDs corresponding to the above two or more LCHs, an LCID that meets the above-mentioned first preset condition.

[0068] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned transceiver unit is further configured to receive third indication information from a network device, and the third indication information is used to instruct the above-mentioned device to use the LCID that meets the above-mentioned first preset condition as an input parameter of the security algorithm of the above-mentioned second PDCP entity.

[0069] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned processing unit is specifically further configured to determine, based on the above-mentioned third indication information, an LCID that meets the above-mentioned first preset condition.

[0070] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned third indication information further includes identification information of the above-mentioned first terminal.

[0071] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned third indication information is carried in third sidelink radio bearer (SLRB) configuration information, and the third SLRB configuration information is carried in a radio resource control (RRC) message, a system information block (SIB), or a preconfigured message.

[0072] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned transceiver unit is further configured to send first indication information to the above-mentioned first terminal, and the first indication information is used to instruct the above-mentioned first terminal to use the LCID that meets the above-mentioned first preset condition as an input parameter of the security algorithm of the first PDCP entity of the above-mentioned first terminal.

[0073] In combination with the ninth aspect and the above possible implementation, in another possible implementation, the above-mentioned first indication information is carried in first sidelink radio bearer (SLRB) configuration information, and the first SLRB configuration information is carried in a PC5-RRC message.

[0074] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the LCID that meets the above first preset condition is the smallest LCID or the largest LCID among the LCIDs corresponding to the two or more LCHs.

[0075] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the above preset condition includes a second preset condition, and the LCH configuration parameter corresponding to the LCID meets the second preset condition.

[0076] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the above processing unit is specifically further configured to determine an LCID that meets the second preset condition based on the LCH configuration parameters of the two or more LCHs.

[0077] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the above transceiver unit is further configured to receive fourth indication information from a network device, where the fourth indication information includes a target LCH configuration parameter, and the fourth indication information is used to instruct the above device to use the LCID that meets the second preset condition as an input parameter of the security algorithm of the second PDCP entity, and the LCID that meets the second preset condition is the LCID corresponding to the target LCH configuration parameter.

[0078] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the above processing unit is specifically further configured to determine an LCID that meets the second preset condition based on the fourth indication information.

[0079] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the fourth indication information is carried in fourth SLRB configuration information, and the fourth SLRB configuration information is carried in an RRC message, a system information block SIB, or a preconfigured message.

[0080] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the above transceiver unit is further configured to send second indication information to the above first terminal, where the second indication information includes a target LCID, and the second indication information is used to instruct the above first terminal to use the target LCID as an input parameter of the security algorithm of the first PDCP entity of the above first terminal, and the target LCID is the LCID corresponding to the LCH that meets the second preset condition determined by the above device.

[0081] Combined with the ninth aspect and the above possible implementation manners, in another possible implementation manner, the second indication information is carried in second SLRB configuration information, and the second SLRB configuration information is carried in a PC5-RRC message.

[0082] In the tenth aspect of the embodiments of the present application, a communication device is provided. The device includes: a processing unit, configured to determine a preset condition; a transceiver unit, configured to send indication information to a second terminal, where the indication information is used to indicate that the second terminal uses a logical channel identifier (LCID) that meets the preset condition as an input parameter of a security algorithm of a second packet data convergence protocol (PDCP) entity of the second terminal, and the second PDCP entity of the second terminal is associated with two or more logical channels (LCHs).

[0083] In combination with the tenth aspect, in a possible implementation manner, the preset condition includes a first preset condition, and the size of the LCID meets the first preset condition; the indication information includes third indication information, and the third indication information is used to indicate that the second terminal uses the LCID that meets the first preset condition as an input parameter of the security algorithm of the second PDCP entity of the second terminal.

[0084] In combination with the tenth aspect and the above possible implementation manner, in another possible implementation manner, the preset condition includes a second preset condition, and configuration parameters of the LCH corresponding to the LCID meet the second preset condition; the indication information includes fourth indication information, and the fourth indication information is used to indicate that the second terminal uses the LCID that meets the second preset condition as an input parameter of the security algorithm of the second PDCP entity of the second terminal.

[0085] In combination with the tenth aspect and the above possible implementation manner, in another possible implementation manner, the fourth indication information further includes target LCH configuration parameters, and the LCID that meets the second preset condition is the LCID corresponding to the target LCH configuration parameters.

[0086] In combination with the tenth aspect and the above possible implementation manner, in another possible implementation manner, the indication information is carried in side-link radio bearer (SLRB) configuration information, and the SLRB configuration information is carried in a radio resource control (RRC) message, a system information block (SIB), or a pre-configured message.

[0087] In the eleventh aspect of the embodiments of the present application, a communication device is provided. The device includes: a processing unit, configured to use an identifier of a first side-link radio bearer (SLRB ID) as an input parameter of a security algorithm to perform security protection on a first data packet; a transceiver unit, configured to send the security-protected first data packet to a first terminal, where the first data packet carries the first SLRB ID.

[0088] In a twelfth aspect of the embodiments of the present application, a communication device is provided. The device includes: a transceiver unit configured to receive a first data packet from a second terminal, where the first data packet includes an identifier SLRB ID of a first sidelink radio bearer; and a processing unit configured to parse the first data packet based on the first SLRB ID.

[0089] Combined with the eleventh aspect or the twelfth aspect, in a possible implementation, the first SLRB ID is carried in the header of the first data packet.

[0090] In a thirteenth aspect of the embodiments of the present application, a communication device is provided. The device includes: a transceiver unit configured to send a first message to a first terminal, where the first message carries an identifier SLRB ID of a first sidelink radio bearer; the transceiver unit is further configured to receive a second message from the first terminal, where the second message is a message after the first terminal performs security protection based on the first SLRB ID; and a processing unit configured to parse the second message based on the first SLRB ID.

[0091] In a fourteenth aspect of the embodiments of the present application, a communication device is provided. The device includes: a transceiver unit configured to receive a first message from a second terminal, where the first message carries an identifier SLRB ID of a first sidelink radio bearer; a processing unit configured to perform security protection on the second message based on the first SLRB ID; and the transceiver unit is further configured to send the second message after security protection to the second terminal.

[0092] Combined with the thirteenth aspect or the fourteenth aspect, in a possible implementation, the first message is a PC5-S message, and the second message is a PC5-S message or a PC5-RRC message.

[0093] For the description of the effects of the above eighth aspect and various implementation manners of the eighth aspect, reference may be made to the description of the corresponding effects of the first aspect and various implementation manners of the first aspect. For the description of the effects of the above ninth aspect and various implementation manners of the ninth aspect, reference may be made to the description of the corresponding effects of the second aspect and various implementation manners of the second aspect. For the description of the effects of the above tenth aspect and various implementation manners of the tenth aspect, reference may be made to the description of the corresponding effects of the third aspect and various implementation manners of the third aspect. For the description of the effects of the above eleventh aspect and various implementation manners of the eleventh aspect, reference may be made to the description of the corresponding effects of the fourth aspect and various implementation manners of the fourth aspect. For the description of the effects of the above twelfth aspect and various implementation manners of the twelfth aspect, reference may be made to the description of the corresponding effects of the fifth aspect and various implementation manners of the fifth aspect. For the description of the effects of the above thirteenth aspect and various implementation manners of the thirteenth aspect, reference may be made to the description of the corresponding effects of the sixth aspect and various implementation manners of the sixth aspect. For the description of the effects of the above fourteenth aspect and various implementation manners of the fourteenth aspect, reference may be made to the description of the corresponding effects of the seventh aspect and various implementation manners of the seventh aspect. Details are not described herein again.

[0094] In a fifteenth aspect of the embodiments of the present application, a computer-readable storage medium is provided. Computer program code is stored in the computer-readable storage medium. When the computer program code runs on a processor, the processor is caused to execute the communication method described in any of the above aspects.

[0095] In a sixteenth aspect of the embodiments of the present application, a computer program product is provided. The program product stores computer software instructions executed by the above processor. The computer software instructions include a program for executing the communication method described in any of the above aspects.

[0096] In a seventeenth aspect of the embodiments of the present application, a communication device is provided. The device includes a processor, and may further include a transceiver and a memory. The transceiver is used for receiving and transmitting information, or for communicating with other network devices. The memory is used for storing computer execution instructions. The processor is used for executing the computer execution instructions to implement the communication method described in any of the above aspects.

[0097] In an eighteenth aspect of the embodiments of the present application, a communication device is provided. The device may exist in the form of a chip product. The structure of the device includes a processor, and may further include a memory. The memory is used for coupling with the processor to store necessary program instructions and data of the device. The processor is used for executing the program instructions stored in the memory to support a terminal device or a network device in executing the communication method described in any of the above aspects.

[0098] In the nineteenth aspect of the embodiments of the present application, a communication device is provided. This device can exist in the form of a chip product. The structure of this device includes a processor and an interface circuit. The processor is used to communicate with other devices through a receiving circuit, enabling this device to execute the communication method described in any of the above aspects.

[0099] In the twentieth aspect of the embodiments of the present application, a communication system is provided, including a first terminal and a second terminal. The first terminal is used to execute the communication method described in the first aspect above, and the second terminal is used to execute the communication method described in the second aspect above.

[0100] In the twenty-first aspect of the embodiments of the present application, a communication system is provided, including a first terminal, a second terminal, and a network device. The first terminal is used to execute the communication method described in the first aspect above, the second terminal is used to execute the communication method described in the second aspect above, and the network device is used to execute the communication method described in the third aspect above.

[0101] In the twenty-second aspect of the embodiments of the present application, a communication system is provided, including a first terminal and a second terminal. The second terminal is used to execute the communication method described in the fourth aspect above, and the first terminal is used to execute the communication method described in the fifth aspect above.

[0102] In the twenty-third aspect of the embodiments of the present application, a communication system is provided, including a first terminal and a second terminal. The second terminal is used to execute the communication method described in the sixth aspect above, and the first terminal is used to execute the communication method described in the seventh aspect above. Description of the Drawings

[0103] Figure 1 It is a schematic diagram of a V2X communication scenario provided by the embodiments of the present application;

[0104] Figure 2 It is a schematic diagram of the structure of a communication device provided by the embodiments of the present application;

[0105] Figure 3 It is a schematic diagram of PDCP replication provided by the embodiments of the present application;

[0106] Figure 4 It is a schematic flowchart of a communication method provided by the embodiments of the present application;

[0107] Figure 5 It is a schematic flowchart of another communication method provided by the embodiments of the present application;

[0108] Figure 6 It is a schematic flowchart of another communication method provided by the embodiments of the present application;

[0109] Figure 7Schematic flowchart of another communication method provided by an embodiment of the present application;

[0110] Figure 8 Schematic flowchart of another communication method provided by an embodiment of the present application;

[0111] Figure 9 Schematic flowchart of another communication method provided by an embodiment of the present application;

[0112] Figure 10 Schematic flowchart of another communication method provided by an embodiment of the present application;

[0113] Figure 11 Schematic diagram of an application when the SLRB ID is an input parameter of a security algorithm provided by an embodiment of the present application;

[0114] Figure 12 Schematic diagram of another application when the SLRB ID is an input parameter of a security algorithm provided by an embodiment of the present application;

[0115] Figure 13 Schematic diagram of the composition of a communication device provided by an embodiment of the present application;

[0116] Figure 14 Schematic diagram of the composition of another communication device provided by an embodiment of the present application;

[0117] Figure 15 Schematic diagram of the composition of another communication device provided by an embodiment of the present application;

[0118] Figure 16 Schematic diagram of the composition of a second terminal provided by an embodiment of the present application;

[0119] Figure 17 Schematic diagram of the composition of a first terminal provided by an embodiment of the present application;

[0120] Figure 18 Schematic diagram of the composition of a network device provided by an embodiment of the present application. Detailed implementation manners

[0121] Next, the technical solutions in the embodiments of the present application will be described in conjunction with the accompanying drawings in the embodiments of the present application. In the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (item)" or its similar expression below refers to any combination of these items, including any combination of single item (item) or multiple items (items). For example, at least one (item) of a, b, or c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple. In addition, in order to clearly describe the technical solutions in the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and roles. Those skilled in the art can understand that the words such as "first" and "second" do not limit the quantity and execution order. For example, the "first" in the first terminal in the embodiments of the present application and the "second" in the second terminal are only used to distinguish different terminal devices.

[0122] It should be noted that in the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific way.

[0123] The embodiments of the present application provide a communication method, and this communication method is applied to Figure 1 the V2X communication scenario shown. As Figure 1 shown, the first terminal and the second terminal communicate through a sidelink (SL). The sidelink refers to the secondary link in the V2X network. In addition to the secondary link in the V2X network, there are also an uplink (UL) and a downlink (DL). Exemplarily, V2X communication includes vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-people (V2P) communication, and vehicle-to-network (V2N) communication, etc. Figure 1Only the V2V communication where both the first terminal and the second terminal are vehicles is taken as an example for illustration, and the specific communication scenarios of V2X in the embodiments of the present application are not limited. For example, the first terminal and the second terminal can communicate with each other between in-vehicle devices, or a road side unit (RSU) can communicate with in-vehicle devices and / or network devices (such as base station devices), or network devices (such as base station devices) can communicate with in-vehicle devices and / or RSU, etc. The network device can be an LTE base station device or an NR base station device or a base station in a subsequent evolved system. It can be understood that the embodiments of the present application do not limit the specific forms of the first terminal and the second terminal, and only exemplary descriptions are provided here. Exemplarily, Figure 1 The access network device in it can be a base station or a device in a network providing wireless access.

[0124] Figure 1 The V2X communication architecture shown contains two communication interfaces, namely the PC5 interface and the Uu interface. The V2X PC5 interface is a direct connection communication interface between V2X terminals. V2X Uu interface communication is a communication mode in which the sending V2X terminal (for example, the second terminal) sends V2X data through the Uu interface to the access network device (for example, the base station), and after being sent to the V2X application server for processing, the V2X application server then sends it down to the access network device and sends it to the receiving V2X terminal (for example, the first terminal) through the access network device. In the V2X Uu interface communication mode, the access network device forwarding the uplink data from the terminal to the server and the access network device forwarding the downlink data sent by the server to the receiving terminal can be the same access network device or different access network devices, which can be specifically determined by the V2X application server.

[0125] Figure 2A communication device provided by an embodiment of the present application. The communication device may be the first terminal or the second terminal in the present application. The communication device may be a vehicle; it may also be an in-vehicle communication device or an in-vehicle terminal used to assist vehicle driving on the vehicle, or a chip in the in-vehicle communication device or the in-vehicle terminal. Among them, the in-vehicle terminal may be a device for implementing wireless communication functions, such as a terminal or a chip that can be used in the terminal. Among them, the terminal may be a user equipment (UE), access terminal, terminal unit, terminal station, mobile station, mobile unit, remote station, remote terminal, mobile device, wireless communication device, terminal agent or terminal device in a 5G network or a future evolved public land mobile network (PLMN). The access terminal may be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication function, computing device or other processing device connected to a wireless modem, in-vehicle device or wearable device, virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc. The in-vehicle terminal may be mobile or fixed.

[0126] As Figure 2 shown, the communication device 200 includes at least one processor 201, a memory 202, a transceiver 203, and a communication bus 204.

[0127] Next, in combination with Figure 2 each component of the communication device will be specifically introduced:

[0128] The processor 201 is the control center of the communication device, which can be a single processor or a collective term for multiple processing elements. For example, the processor 201 can be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention, such as one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs).

[0129] Among them, the processor 201 can execute various functions of the communication device by running or executing software programs stored in the memory 202 and calling data stored in the memory 202.

[0130] In a specific implementation, as an embodiment, the processor 201 may include one or more CPUs, such as Figure 2 CPU0 and CPU1 shown in

[0131] In a specific implementation, as an embodiment, the communication device may include multiple processors, such as Figure 2 the processor 201 and the processor 205 shown in

[0132] The memory 202 can be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM), or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 202 can exist independently and be connected to the processor 201 through the communication bus 204. The memory 202 can also be integrated with the processor 201.

[0133] Among them, the memory 202 is used to store the software program for executing the solution of the present invention and is controlled by the processor 201 for execution.

[0134] The transceiver 203 is used to communicate with other communication devices. Of course, the transceiver 203 can also be used to communicate with a communication network, such as Ethernet, a radio access network (RAN), a wireless local area network (WLAN), etc. The transceiver 203 can include a receiving unit to implement the receiving function and a transmitting unit to implement the transmitting function.

[0135] The communication bus 204 can be an industry standard architecture (ISA) bus, a peripheral component interconnect (PCI) bus, or an extended industry standard architecture (EISA) bus, etc. This bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of convenience of representation, Figure 2 only a thick line is shown in the figure, but it does not mean that there is only one bus or one type of bus.

[0136] Figure 2 The communication device structure shown in the figure does not limit the communication device, and it can include more or fewer components than shown in the figure, or combine some components, or have different component arrangements.

[0137] In V2X, before D2D performs unicast communication, PC5-S connection establishment and security establishment need to be carried out. After the PC5-S connection establishment and security establishment are completed, subsequent data transmission at the corresponding AS layer and transmission of PC5-S messages can be protected based on the security algorithm negotiated by the transceiver UEs during the PC5-S connection establishment.

[0138] When the input of the security algorithm at the AS layer is LCID, in order to improve the reliability of service transmission, PDCP duplication can be introduced. As Figure 3 shown, after the PDCP entity performs security algorithm operations (such as integrity protection and encryption operations) on a PDCP packet, it will duplicate and transmit a PDCP packet to multiple radio link control (RLC) entities. For example, Figure 3 the primary RLC entity and the secondary RLC entity in Figure 3 . The two RLC entities will process independently and transmit the processed packets to the medium access control (MAC) layer through two LCHs. For the MAC, the packets transmitted by the two RLC entities are two independent packets, and the MAC layer cannot recognize whether this is a packet transmitted by PDCP duplication. The MAC layer only needs to schedule according to the algorithm. It should be noted that a PDCP entity can also be associated with more RLC entities / LCHs.

[0139] Since the LCID needs to be used as an input parameter of the security algorithm when performing the security algorithm, and when PDCP duplication is introduced, a PDCP entity can be associated with multiple LCHs, and the multiple LCHs correspond to different LCIDs. Therefore, when the PDCP entities of the sending UE and the receiving UE perform the security algorithm, different LCIDs may be used as the input parameters of the security algorithm, which will cause the receiving UE to be unable to correctly parse the data packets sent by the sending UE, resulting in the receiving UE failing to receive data and causing the SL between the sending UE and the receiving UE to fail to communicate normally.

[0140] When solving the problem that when the PDCP entities of the sending and receiving UEs are associated with multiple LCHs, it is impossible to ensure the consistency of the input parameters when the sending and receiving UEs execute the security algorithm in the corresponding PDCP entities, resulting in the failure of SL communication. An embodiment of the present application provides a communication method, which can ensure the consistency of the input parameters when the sending and receiving UEs execute the security algorithm in the corresponding PDCP entities, ensure the normal communication of SL, and improve the reliability of communication.

[0141] Combined with Figures 1 - 3 , as Figure 4 shown, it is a communication method provided by an embodiment of the present application, and the communication method includes steps S401-S406.

[0142] S401. The second terminal determines a first LCID that meets a preset condition.

[0143] The second PDCP entity of the second terminal is associated with two or more LCHs, and one LCH can correspond to one LCID. The LCID corresponding to each LCH can be allocated by the second terminal or obtained through negotiation between the second terminal and the first terminal.

[0144] Exemplarily, the second terminal may include one or more second PDCP entities, and one second PDCP entity may be associated with two or more LCHs. The number of LCHs associated with different second PDCP entities may be the same or different. The embodiment of the present application does not limit the number of second PDCP entities included in the second terminal and the specific number of LCHs associated with each second PDCP entity. When the second terminal includes multiple second PDCP entities, each second PDCP entity may correspond to a first LCID, and the first LCID may be an LCID that meets the preset condition among the LCIDs corresponding to the multiple LCHs associated with the first PDCP. The first LCID is an input parameter for the second PDCP entity to execute the security algorithm. It should be noted that the first LCID described in the embodiment of the present application as an input parameter for the second PDCP entity to execute the security algorithm means that the first LCID is an input parameter when the second PDCP entity executes the security algorithm, and the second PDCP entity may also include other input parameters when executing the security algorithm.

[0145] It should be noted that within a unicast connection communication, the LCID is unique. That is, within a unicast connection communication with the same sender ID and receiver ID, the LCID corresponding to the LCH associated with the PDCP entity of the sender / receiver is unique. Exemplarily, the sender ID and receiver ID are layer 2 identifiers, L2 ID. For example, taking the second terminal as UE1, the first terminal as UE2, UE1 includes 2 second PDCP entities, one second PDCP entity is associated with 2 LCHs, and the other second PDCP entity is associated with 3 LCHs. UE2 includes 2 first PDCP entities, one first PDCP entity is associated with 2 LCHs, and the other first PDCP entity is associated with 3 LCHs. In the unicast connection communication between UE1 and UE2, the 5 LCIDs corresponding to the LCHs associated with the 2 second PDCP entities of UE1 are different from each other, and the LCID corresponding to each LCH is unique within the unicast connection communication between UE1 and UE2. It can be understood that the two second PDCP entities of UE1 correspond to the two first PDCP entities of UE2 respectively. The LCID corresponding to the LCH associated with the second PDCP entity of UE1 is the same as the LCID corresponding to the LCH associated with the first PDCP entity in UE2 that corresponds to the second PDCP entity.

[0146] Exemplarily, the above preset condition may include a first preset condition. The size of the above first LCID meets the first preset condition. The first LCID may be the LCID among the LCIDs corresponding to two or more LCHs associated with the second PDCP entity of the second terminal, and the size of the LCID meets the first preset condition.

[0147] Exemplarily, the above first preset condition may be the largest LCID, the smallest LCID, the second largest LCID, or the second smallest LCID, etc. For example, when the first preset condition is the largest LCID, the first LCID is the largest LCID among the LCIDs corresponding to two or more LCHs associated with the second PDCP entity of the second terminal. When the first preset condition is the smallest LCID, the first LCID is the smallest LCID among the LCIDs corresponding to two or more LCHs associated with the second PDCP entity of the second terminal. When the first preset condition is the second smallest LCID, the first LCID is the second smallest LCID among the LCIDs corresponding to two or more LCHs associated with the second PDCP entity of the second terminal. When the first preset condition is the second largest LCID, the first LCID is the second largest LCID among the LCIDs corresponding to two or more LCHs associated with the second PDCP entity of the second terminal. The embodiments of the present application do not limit the specific first preset condition that the size of the first LCID meets. The following embodiments only take the size of the first LCID being the largest or the smallest as an example for illustration.

[0148] In the first implementation manner, the above step S401 may include: The second terminal determines a first LCID that meets the first preset condition based on a preset rule. The preset rule is a predefined rule. For example, the preset rule may be a rule stipulated by the protocol, and the second terminal may determine the first LCID that meets the first preset condition based on the rule stipulated by the protocol.

[0149] For example, the protocol may stipulate that among the LCIDs corresponding to two or more LCHs associated with a PDCP entity, the largest LCID or the smallest LCID is used as the input parameter of the security algorithm of the PDCP entity. In this implementation manner, if the second terminal includes multiple second PDCP entities, then each second PDCP entity determines the largest LCID or the smallest LCID among the LCIDs corresponding to the LCHs associated with it as the first LCID, and this first LCID is the input parameter of the security algorithm of the second PDCP entity. That is, all the second PDCP entities included in the second terminal determine the LCID whose size meets the first preset condition among the LCIDs corresponding to the LCHs associated with them based on this preset rule.

[0150] It can be understood that in this implementation manner, both the second terminal and the first terminal can determine to use one LCID among multiple LCIDs as the input parameter of the security algorithm based on the preset rule stipulated by the protocol, and the LCIDs of the second terminal and the first terminal correspond one by one. Therefore, based on this rule, when the security algorithm is executed on the corresponding PDCP entities of the second terminal and the first terminal, the input parameters of the security algorithm are the same. In this implementation manner, without the need for interaction between the second terminal and the first terminal about this rule, the consistency of the input parameters when the security algorithm is executed on the corresponding PDCP entities of the second terminal and the first terminal can be ensured.

[0151] In the second implementation manner, the above step S401 may include: The second terminal determines a first LCID that meets the first preset condition based on the sizes of the LCIDs corresponding to two or more LCHs. Exemplarily, in this implementation manner, the second terminal may independently determine to use one LCID among multiple LCIDs as the input parameter of the security algorithm based on the size of the LCID.

[0152] In this implementation, one LCID among the LCIDs corresponding to multiple LCHs associated with the second PDCP entity can be determined by the AS layer of the second terminal or the upper layer of the second terminal as an input parameter for the security algorithm of the second PDCP entity. The aforementioned AS layer may include one or more of the PDCP layer, RLC layer, MAC layer, physical (PHY) layer, service data adaptation protocol (SDAP), and radio resource control (RRC) layer. The upper layer of the second terminal can be a layer above the AS layer of the second terminal. For example, the PC5-S layer of the second terminal or the V2X layer of the second terminal.

[0153] Exemplarily, in this implementation, when the second terminal includes multiple second PDCP entities, the sizes of the first LCIDs corresponding to all the second PDCP entities in the second terminal can meet the same first preset condition. For example, the second terminal can determine the smallest LCID among the LCIDs corresponding to the LCHs associated with each second PDCP entity as the first LCID corresponding to this PDCP entity. For another example, the second terminal can also determine the largest LCID among the LCIDs corresponding to the LCHs associated with each second PDCP entity as the first LCID corresponding to this PDCP entity.

[0154] Exemplarily, in this implementation, when the second terminal includes multiple second PDCP entities, the sizes of the first LCIDs corresponding to different second PDCP entities in the second terminal can also meet different first preset conditions. For example, the second terminal includes two second PDCP entities, namely PDCP1 and PDCP2. The second terminal can determine the smallest LCID among the LCIDs corresponding to the LCHs associated with PDCP1 as the first LCID corresponding to PDCP1, that is, use the smallest LCID among the LCIDs corresponding to the LCHs associated with PDCP1 as the input parameter for the security algorithm of PDCP1. Determine the largest LCID among the LCIDs corresponding to the LCHs associated with PDCP2 as the first LCID corresponding to PDCP2, that is, use the largest LCID among the LCIDs corresponding to the LCHs associated with PDCP2 as the input parameter for the security algorithm of PDCP2. That is to say, for different second PDCP entities of the second terminal, the first preset condition that the size of the first LCID conforms to can be different.

[0155] It should be noted that this application embodiment does not limit whether the first preset conditions that the first LCIDs corresponding to different second PDCP entities of the second terminal conform to are the same.

[0156] It can be understood that in this implementation manner, after the second terminal determines to use the LCID that meets the first preset condition as the first LCID, it may send indication information to the first terminal to inform the first terminal of the LCID that is used as the input parameter of the security algorithm of the corresponding first PDCP entity, so as to ensure that the input parameters of the second terminal and the first terminal are consistent when the security algorithm is executed on the corresponding PDCP entities.

[0157] In the third implementation manner, before the above step S401, the following steps may further be included: The second terminal receives third indication information from the network device, where the third indication information is used to instruct the second terminal to use the LCID that meets the first preset condition as the input parameter of the security algorithm of the second PDCP entity. Correspondingly, the above step S401 includes: The second terminal determines a first LCID that meets the first preset condition based on the third indication information. Exemplarily, the above network device may be an access network device or a core network device, and the embodiments of the present application do not limit this.

[0158] Exemplarily, taking the third indication information instructing the second terminal to use the smallest LCID as the input parameter of the security algorithm of the second PDCP entity as an example. The second terminal may determine the smallest LCID among the LCIDs corresponding to two or more LCHs associated with the second PDCP as the LCID that meets the first preset condition based on the third indication information. That is, the second terminal may determine the LCID that meets the first preset condition based on the third indication information of the network device.

[0159] Exemplarily, taking the first preset condition as the smallest LCID. The above third indication information may instruct the second terminal to determine the smallest LCID among the LCIDs corresponding to two or more LCHs associated with each second PDCP entity as the input parameter of the security algorithm of the second PDCP entity. The above third indication information may also instruct the second terminal to determine the smallest LCID among the LCIDs corresponding to two or more LCHs associated with a certain second PDCP entity as the input parameter of the security algorithm of the second PDCP entity. That is, the granularity indicated by the third indication information may be for all second PDCP entities of the second terminal or for a certain second PDCP entity. When the granularity indicated by the third indication information is for a certain second PDCP entity, the sizes of the first LCIDs corresponding to different second PDCP entities may meet different first preset conditions.

[0160] Optionally, the above third indication information may further include the first LCID. That is, the network device instructs the second terminal to use the first LCID that meets the preset condition determined by the network device as the input parameter of the security algorithm of the second PDCP entity of the second terminal through the third indication information.

[0161] Exemplarily, the above-mentioned third indication information may be carried in the third side link radio bearer (SLRB) configuration information, and the third SLRB configuration information may include one or more of service data adaptation protocol (SDAP) configuration information, PDCP configuration information, radio link control (RLC) configuration information, LCH configuration information, SLRB ID / index, and LCID / LCH index. When the third indication information can be carried in the third SLRB configuration information, the third indication information in the third SLRB configuration information is used to indicate the second terminal to determine the LCIDs that meet the first preset condition among the LCIDs corresponding to two or more LCHs associated with the second PDCP entity corresponding to the SLRB as the input parameters of the security algorithm of the second PDCP entity.

[0162] It can be understood that the SLRB index is the index corresponding to the SLRB configuration information, and the LCH index is the index corresponding to the LCH configuration.

[0163] Exemplarily, the above-mentioned third SLRB configuration information may be carried in an RRC message, a system information block (SIB), or a pre-configured message.

[0164] Optionally, the above-mentioned third indication information may further include the identification information of the first terminal. When the third indication information includes the identification information of the first terminal, the above-mentioned third indication information is specifically used to indicate the second terminal to use the LCIDs that meet the first preset condition in the unicast connection communication between the second terminal and the first terminal as the input parameters of the security algorithm of the second PDCP entity. It can be understood that in different unicast connection communications of the second terminal, the LCIDs corresponding to the LCHs associated with different PDCP entities of the second terminal may be the same. When the network device indicates the second terminal to use the LCIDs that meet the first preset condition as the input parameters of the security algorithm of the PDCP entity of the second terminal, it may indicate the second terminal to use the LCIDs with LCID sizes that meet the conditions in a certain unicast connection communication as the input parameters of the security algorithm of the PDCP entity of the second terminal. Exemplarily, the identification information of the first terminal may be the source layer 2 ID (source L2 ID) of the first terminal.

[0165] It can be understood that when the third indication information does not include the identification information of the first terminal, when the second terminal determines the LCID that meets the first preset condition, it may not distinguish specific unicast connections. For example, taking the first preset condition as the smallest LCID, the second terminal may use the smallest LCID among the LCIDs corresponding to the LCHs associated with each second PDCP entity of the second terminal within the unicast connection between the second terminal and the first terminal as the input parameter for the second PDCP entity to execute the security algorithm. For another example, the second terminal may also use the smallest LCID among the LCIDs corresponding to the LCHs associated with each second PDCP entity of the second terminal within the unicast connection between the second terminal and the third terminal as the input parameter for the second PDCP entity to execute the security algorithm. That is to say, when the second terminal determines the first LCID, it does not distinguish different unicast connections.

[0166] Exemplarily, the above preset condition may include a second preset condition. The LCH configuration parameter corresponding to the first LCID meets the second preset condition. That is, the first LCID may be the LCID corresponding to the LCH among two or more LCHs associated with the second PDCP entity of the second terminal, where the LCH configuration parameter meets the second preset condition.

[0167] Exemplarily, the above LCH configuration parameter may include one or more of the following parameters: the priority of the LCH, the logical channel identifier LCID, the prioritised bit rate (PBR), the bucket size duration (BSD), the allowed carriers, the subcarrier spacing (SCS), the maximum physical sidelink shared channel (PSSCH) support time (maxPSSCH-duration), the configured grant type1allowed (CG), the logical channel group identifier (LCG ID), the scheduling request ID (SR ID), etc. For example, the above second preset condition may be that the priority of the LCH is the highest. For another example, the above second preset condition may also be the LCH associated with the CG or the LCH associated with a certain CG. The embodiments of the present application do not limit the specific parameters included in the LCH configuration parameter and the specific content of the second preset condition, and only exemplary descriptions are provided here. It should be understood that the LCH configuration parameter may be in the form of a list or a set. For example, the SCS parameter in an LCH configuration parameter is an SCS list.

[0168] In the fourth implementation manner, the above step S401 may include: The second terminal determines a first LCID that meets the second preset condition based on a preset rule. The preset rule is a predefined rule. The predefined in this application can be understood as defined, predefined, stored, prestored, pre-negotiated, pre-configured, solidified, or pre-burned. For example, the preset rule may be a rule stipulated by a protocol, and the second terminal may determine the LCID that meets the second preset condition based on the rule stipulated by the protocol.

[0169] For example, the protocol may stipulate that among two or more LCHs associated with the second PDCP entity of the second terminal, the LCID corresponding to the LCH with the highest priority is used as the input parameter of the security algorithm of the second PDCP entity. In this implementation manner, if the second terminal includes multiple second PDCP entities, then each second PDCP entity uses the LCID corresponding to the LCH with the highest priority among the LCHs associated with it as the input parameter of the security algorithm of the second PDCP entity. That is, all the second PDCP entities included in the second terminal determine, based on this preset rule, the LCID corresponding to the LCH whose LCH configuration parameters meet the second preset condition among the LCHs associated with them.

[0170] It can be understood that in this implementation manner, both the second terminal and the first terminal can determine the LCID used as the input parameter of the security algorithm based on the preset rule stipulated by the protocol, and the LCHs associated with the PDCP entities of the second terminal correspond to the LCHs associated with the PDCP entities of the first terminal. Therefore, based on this rule, when the security algorithm is executed on the corresponding PDCP entities, the input parameters of the security algorithm are the same. In this implementation manner, without the need for interaction between the second terminal and the first terminal regarding this rule, the consistency of the input parameters when the security algorithm is executed on the corresponding PDCP entities of the second terminal and the first terminal can be ensured.

[0171] In the fifth implementation manner, the above step S401 may include: The second terminal determines a first LCID that meets the second preset condition based on the LCH configuration parameters of two or more LCHs. Exemplarily, in this implementation manner, the second terminal may independently determine the LCID used as the input parameter of the security algorithm based on the LCH configuration parameters.

[0172] Exemplarily, in this implementation manner, when the second terminal includes multiple second PDCP entities, the second terminal may use the LCID corresponding to the LCH that meets the second preset condition among the LCH configuration parameters of the LCH associated with each second PDCP entity as the input parameter of the security algorithm of this second PDCP entity. The second terminal may also use the LCIDs corresponding to the LCHs that meet different second preset conditions among the LCH configuration parameters of the LCHs associated with different PDCP entities as the input parameters of the security algorithm of this second PDCP entity. That is to say, the LCH configuration parameters of the first LCID corresponding to all second PDCP entities in the second terminal may meet the same second preset condition. The LCH configuration parameters of the first LCID corresponding to different second PDCP entities in the second terminal may also meet different second preset conditions.

[0173] For example, the second terminal may determine the LCID corresponding to the LCH with the highest priority among the LCH configuration parameters of the LCH associated with each second PDCP entity as the first LCID corresponding to this PDCP entity. For another example, the second terminal includes two second PDCP entities, namely PDCP1 and PDCP2. The second terminal may determine the LCID corresponding to the LCH with the highest priority among the configuration parameters of the LCH associated with PDCP1 as the first LCID corresponding to PDCP1, that is, use the LCID corresponding to the LCH with the highest priority among the configuration parameters of the LCH associated with PDCP1 as the input parameter of the security algorithm of PDCP1. The LCID corresponding to the LCH associated with CG among the configuration parameters of the LCH associated with PDCP2 is determined as the first LCID corresponding to PDCP2, that is, use the LCID corresponding to the LCH associated with CG among the configuration parameters of the LCH associated with PDCP2 as the input parameter of the security algorithm of PDCP2.

[0174] It should be noted that the embodiments of the present application do not limit whether the second preset conditions met by the first LCIDs corresponding to different second PDCP entities of the second terminal are the same.

[0175] It can be understood that, in this implementation manner, after the second terminal determines to use the LCID that meets the second preset condition as the first LCID, it may send an indication message to the first terminal to inform the corresponding first PDCP entity in the first terminal to use this LCID as the input parameter of the security algorithm of this first PDCP entity, so as to ensure that the input parameters of the second terminal and the first terminal are consistent when the corresponding PDCP entities execute the security algorithm.

[0176] In a sixth implementation manner, before the above step S401, the following steps may further be included: The second terminal receives fourth indication information from a network device, where the fourth indication information includes target LCH configuration parameters, and the fourth indication information is used to instruct the second terminal to use an LCID that meets a second preset condition as an input parameter of the security algorithm of the second PDCP entity, and the LCID that meets the second preset condition is the LCID corresponding to the target LCH configuration parameter. Correspondingly, the above step S401 includes: The second terminal determines a first LCID that meets the second preset condition based on the fourth indication information. Exemplarily, the above network device may be an access network device or a core network device, and the embodiments of the present application do not limit this.

[0177] Exemplarily, taking the fourth indication information instructing the second terminal to use the LCID corresponding to the LCH with the highest priority as the input parameter of the security algorithm of the second PDCP entity as an example. The second terminal may determine, based on the fourth indication information, that the LCID corresponding to the LCH with the highest priority among the LCH configuration parameters of two or more LCHs associated with the first PDCP is the LCID that meets the second preset condition. That is, the second terminal may determine the LCID that meets the second preset condition based on the fourth indication information of the network device.

[0178] Exemplarily, taking the second preset condition as the highest priority of the LCH as an example. The above fourth indication information may instruct the second terminal to determine, as the input parameter of the security algorithm of the second PDCP entity, the LCID corresponding to the LCH with the highest priority among the LCH configuration parameters of two or more LCHs associated with each second PDCP entity. The above fourth indication information may also instruct the second terminal to determine, as the input parameter of the security algorithm of the second PDCP entity, the LCID corresponding to the LCH with the highest priority among the LCH configuration parameters of two or more LCHs associated with a certain second PDCP entity. That is, the granularity indicated by the fourth indication information may be for all second PDCP entities of the second terminal or for a certain second PDCP entity. When the granularity indicated by the fourth indication information is a certain second PDCP entity, the LCH configuration parameters of the first LCID corresponding to different second PDCP entities may meet different second preset conditions.

[0179] Exemplarily, the above-mentioned fourth indication information may be carried in the fourth SLRB configuration information, which may include one or more of SDAP configuration information, PDCP configuration information, RLC configuration information, LCH configuration information, SLRB ID / index, and LCID / LCH index. When the fourth indication information is carried in the fourth SLRB configuration information, the fourth indication information in the fourth SLRB configuration information is used to indicate the second terminal to determine the LCID corresponding to the LCH whose LCH configuration parameters meet the second preset condition among two or more LCHs associated with the second PDCP entity corresponding to the SLRB as the input parameter of the security algorithm of the second PDCP entity.

[0180] Exemplarily, the above-mentioned fourth SLRB configuration information may be carried in an RRC message, an SIB, or a pre-configured message.

[0181] It can be understood that in this embodiment, the second terminal may determine the LCID that meets the preset condition through multiple implementation manners, and this application embodiment does not limit which of the above manners the second terminal specifically uses to determine the LCID that meets the preset condition.

[0182] S402. The first terminal determines a second LCID that meets the preset condition.

[0183] The first PDCP entity of the first terminal is associated with two or more LCHs. The first PDCP entity of the first terminal corresponds to the second PDCP entity of the second terminal. The LCHs associated with the first PDCP entity of the first terminal correspond to the LCHs associated with the second PDCP entity of the second terminal.

[0184] Exemplarily, the preset condition in step S402 may be the same as the preset condition in step S401. Therefore, for a corresponding group of PDCP entities in the second terminal and the first terminal, the second LCID determined by the first terminal in step S402 that meets the preset condition is the same as the first LCID determined by the second terminal in step S401 that meets the preset condition. This second LCID that meets the preset condition may be used as the input parameter for the first PDCP entity of the first terminal to execute the security algorithm. That is to say, the first LCID determined by the second terminal in step S401 as the input parameter of the security algorithm of the second PDCP entity is the same as the second LCID determined by the first terminal in step S402 as the input parameter of the security algorithm of the first PDCP entity.

[0185] Exemplarily, the above preset condition may include a first preset condition. The size of the second LCID meets the first preset condition. The second LCID may be the LCID among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal, and the size of the LCID meets the first preset condition.

[0186] Exemplarily, the above first preset condition may be that the LCID is the largest, the LCID is the smallest, the LCID is the second largest, or the LCID is the second smallest, etc. For example, when the first preset condition is that the LCID is the largest, the second LCID is the largest LCID among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal. When the first preset condition is that the LCID is the smallest, the second LCID is the smallest LCID among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal. When the first preset condition is that the LCID is the second smallest, the second LCID is the second smallest LCID among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal. When the first preset condition is that the LCID is the second largest, the second LCID is the second largest LCID among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity of the first terminal. The embodiments of the present application do not limit the specific first preset condition that the size of the second LCID meets. It should be noted that the first preset condition that the size of the second LCID meets is the same as the first preset condition that the size of the first LCID meets in the foregoing steps.

[0187] In a first implementation manner, the above step S402 may include: The first terminal determines a second LCID that meets the first preset condition based on a preset rule. The preset rule is a predefined rule. For example, the preset rule may be a rule stipulated by the protocol, and the first terminal may determine a second LCID that meets the first preset condition based on the rule stipulated by the protocol.

[0188] For example, the protocol may stipulate that the largest LCID or the smallest LCID among the LCIDs corresponding to two or more LCHs associated with the PDCP entity of the terminal is used as the input parameter of the security algorithm of the PDCP entity. In this implementation manner, if the first terminal includes multiple first PDCP entities, then each first PDCP entity uses the largest LCID or the smallest LCID among the LCIDs corresponding to the LCHs associated with it as the input parameter of the security algorithm of the first PDCP entity. That is, all the first PDCP entities included in the first terminal determine, based on the preset rule, a second LCID among the LCIDs corresponding to the LCHs associated with them, and the size of the second LCID meets the first preset condition.

[0189] It should be noted that when the protocol stipulates that the largest or smallest LCID is used as the input parameter of the security algorithm, all terminals can, based on this regulation, determine that among the LCIDs corresponding to multiple LCHs associated with the PDCP entity of the terminal, the largest or smallest LCID is used as the input parameter of the security algorithm of the PDCP entity.

[0190] It can be understood that in this implementation manner, the second terminal and the first terminal can determine the LCID used as the input parameter of the security algorithm based on the same preset rule stipulated by the protocol, and the LCIDs of the second terminal and the first terminal correspond one by one. Therefore, based on this rule, when the security algorithm is executed on the corresponding PDCP entities of the second terminal and the first terminal, the input parameters of the security algorithm are the same. Thus, it is ensured that the input parameters are consistent when the security algorithm is executed on the corresponding PDCP entities of the second terminal and the first terminal.

[0191] In the second implementation manner, before the above step S402, it may further include: the first terminal receives first indication information from the second terminal, and the first indication information is used to instruct the first terminal to use the LCID that meets the first preset condition as the input parameter of the security algorithm of the first PDCP entity. Correspondingly, the above step S402 includes: the first terminal determines a second LCID that meets the first preset condition based on the first indication information.

[0192] Exemplarily, taking the first indication information instructing the first terminal to use the smallest LCID as the input parameter of the security algorithm of the first PDCP entity as an example. The first terminal can determine the smallest LCID among the LCIDs corresponding to two or more LCHs associated with the second PDCP as the second LCID that meets the first preset condition based on the first indication information. That is, the first terminal can determine the second LCID that meets the first preset condition based on the first indication information of the second terminal.

[0193] Optionally, the above first indication information may further include a first LCID. That is, the second terminal directly instructs the first terminal to use the first LCID determined by the second terminal and meeting the preset condition as the input parameter of the security algorithm of the first PDCP entity of the first terminal through the first indication information.

[0194] Exemplarily, taking the first preset condition as the smallest LCID as an example. The above first indication information may instruct the first terminal to determine the smallest LCID among the LCIDs corresponding to two or more LCHs associated with each first PDCP entity as the input parameter of the security algorithm of the first PDCP entity. The above first indication information may also instruct the first terminal to determine the smallest LCID among the LCIDs corresponding to two or more LCHs associated with a certain first PDCP entity as the input parameter of the security algorithm of the first PDCP entity. That is, the granularity indicated by the first indication information may be for all first PDCP entities of the first terminal or for a certain first PDCP entity. When the granularity indicated by the first indication information is a certain first PDCP entity, the sizes of the second LCIDs corresponding to different first PDCP entities may satisfy different first preset conditions.

[0195] Exemplarily, the above first indication information may be carried in the first SLRB configuration information, and the first SLRB configuration information may include one or more of SDAP configuration information, PDCP configuration information, RLC configuration information, LCH configuration information, SLRB ID / index, LCID / LCH index. When the first indication information is carried in the first SLRB configuration information, the first indication information in the first SLRB configuration information is used to instruct the first terminal to determine the LCID that meets the first preset condition among the LCIDs corresponding to two or more LCHs associated with the first PDCP entity corresponding to the SLRB as the input parameter of the security algorithm of the first PDCP entity.

[0196] Exemplarily, the above first SLRB configuration information may be carried in the PC5 - RRC message.

[0197] Exemplarily, the above preset condition may include a second preset condition. The LCH configuration parameters corresponding to the second LCID meet the second preset condition. That is, the second LCID may be the LCID corresponding to the LCH among two or more LCHs associated with the first PDCP entity of the first terminal, and the LCH configuration parameters meet the second preset condition. For the specific content of the LCH configuration parameters and the second preset condition, reference may be made to the relevant description in step S401, which will not be elaborated here.

[0198] In the third implementation manner, the above step S402 may include: The first terminal determines a second LCID that meets the second preset condition based on a preset rule. The preset rule is a predefined rule. For example, the preset rule may be a rule stipulated by the protocol, and the first terminal may determine a second LCID that meets the second preset condition based on the rule stipulated by the protocol.

[0199] For example, the protocol may stipulate that among two or more LCHs associated with a PDCP entity, the LCID corresponding to the LCH with the highest priority is used as the input parameter of the security algorithm of the PDCP entity. In this implementation manner, if the first terminal includes multiple first PDCP entities, then each first PDCP entity uses the LCID corresponding to the LCH with the highest priority among the LCHs associated with it as the input parameter of the security algorithm of the first PDCP entity. That is, all the first PDCP entities included in the first terminal determine, based on the preset rule, the LCID corresponding to the LCH whose LCH configuration parameter meets the second preset condition among the LCHs associated with them.

[0200] It should be noted that in this implementation manner, when both the first terminal and the second terminal determine the LCID based on the implementation manner of the LCH configuration parameter, the LCH configuration parameter of the first terminal is the configuration parameter obtained from the second terminal. Therefore, the configuration parameters of the LCHs associated with the first PDCP entity of the first terminal are the same as those of the LCHs associated with the second PDCP entity of the second terminal. Thus, when the second terminal and the first terminal determine the LCID used as the input parameter of the security algorithm based on the preset rule stipulated by the protocol, this LCID is the same. This ensures the consistency of the input parameters when the corresponding PDCP entities of the second terminal and the first terminal execute the security algorithm.

[0201] In the fourth implementation manner, before the above step S402, it may further include: the first terminal receives second indication information from the second terminal. The second indication information includes a first LCID, and the second indication information is used to instruct the first terminal to use the first LCID as the input parameter of the security algorithm of the first PDCP entity. The first LCID is the LCID corresponding to the LCH determined by the second terminal to meet the second preset condition. Correspondingly, the above step S402 includes: the first terminal determines a second LCID that meets the second preset condition based on the second indication information. That is to say, in this implementation manner, the second terminal may send the first LCID determined by the second terminal that meets the preset condition to the first terminal and instruct the first terminal to use the first LCID as the input parameter of the security algorithm of the first PDCP entity of the first terminal. That is, the above second LCID is the first LCID.

[0202] Optionally, the above second indication information may further include a target LCH configuration parameter that meets the second preset condition. For example, the second indication information includes that the priority of the LCH is the highest, and the second indication information may instruct the first terminal to use the LCID corresponding to the LCH with the highest priority as the input parameter of the security algorithm of the first PDCP entity.

[0203] Exemplarily, taking the second preset condition that the priority of LCH is the highest as an example. The above second indication information may indicate that the first terminal determines the LCID corresponding to the LCH with the highest priority among the LCH configuration parameters of two or more LCHs associated with each first PDCP entity as the input parameter of the security algorithm of the first PDCP entity. The above second indication information may also indicate that the first terminal determines the LCID corresponding to the LCH with the highest priority among the LCH configuration parameters of two or more LCHs associated with a certain first PDCP entity as the input parameter of the security algorithm of the first PDCP entity. That is, the granularity indicated by the second indication information may be for all first PDCP entities of the first terminal or for a certain first PDCP entity. When the granularity indicated by the second indication information is a certain first PDCP entity, the LCH configuration parameters of the second LCID corresponding to different first PDCP entities may satisfy different second preset conditions.

[0204] Exemplarily, the above second indication information may be carried in the second SLRB configuration information, and the second SLRB configuration information may include one or more of SDAP configuration information, PDCP configuration information, RLC configuration information, LCH configuration information, SLRB ID / index, LCID / LCH index. When the second indication information is carried in the second SLRB configuration information, the second indication information in the second SLRB configuration information is used to indicate that the first terminal determines the LCID corresponding to the LCH whose LCH configuration parameters meet the second preset condition among two or more LCHs associated with the first PDCP entity corresponding to the SLRB as the input parameter of the security algorithm of the first PDCP entity.

[0205] Exemplarily, the above second SLRB configuration information may be carried in the PC5-RRC message.

[0206] It can be understood that in this embodiment, the first terminal can determine the LCID that meets the preset condition through multiple implementation manners, and the embodiments of the present application do not limit which of the above manners the first terminal specifically uses to determine the LCID that meets the preset condition. It should be noted that the second LCID determined by the first terminal that meets the preset condition in this embodiment is the same as the first LCID determined by the foregoing second terminal that meets the preset condition.

[0207] It should be noted that when the second terminal determines the first LCID based on the preset rules specified in the protocol, the present application embodiment does not limit the execution order of the above steps S401 and S402. For example, S401 can be executed before S402, can be executed after S402, or can be executed simultaneously with S402. When the second terminal independently determines the first LCID, or when the second terminal determines the first LCID based on the indication information of the network device, the above step S402 is executed after step S401.

[0208] It should be noted that when the second terminal determines the first LCID by adopting the fifth implementation manner or the sixth implementation manner in the above step S401, in step S402, the first terminal can determine the second LCID by adopting the fourth implementation manner or can determine the second LCID by adopting the second implementation manner. When the first terminal determines the second LCID by adopting the second implementation manner in step S402, the above first indication information includes the first LCID to ensure that the first LCID determined by the second terminal is the same as the second LCID determined by the first terminal.

[0209] S403. The second terminal uses the first LCID as the input parameter of the security algorithm of the second PDCP entity to perform security protection on the first data packet.

[0210] Exemplarily, the above security protection of the first data packet by the second terminal may include: the second PDCP entity of the second terminal encrypts and / or performs integrity protection on the first data packet.

[0211] Exemplarily, when the preset condition includes the above first preset condition. Correspondingly, in step S403, the second terminal may use the LCID that meets the first preset condition determined in step S401 as the input parameter of the security algorithm of the second PDCP entity to perform security protection on the first data packet.

[0212] Exemplarily, when the preset condition includes the above second preset condition. Correspondingly, in step S403, the second terminal may use the LCID that meets the second preset condition determined in step S401 as the input parameter of the security algorithm of the second PDCP entity to perform security protection on the first data packet.

[0213] It should be noted that in the embodiment of the present application, the LCID that meets the preset condition is also the input parameter when the first PDCP entity of the first terminal parses the first data packet. The first PDCP entity of the first terminal corresponds to the second PDCP entity of the second terminal, so as to ensure that the input parameters of the second terminal and the first terminal when performing the security algorithm in the corresponding PDCP entities are consistent, so that the SL communication between the second terminal and the first terminal is normal.

[0214] It can be understood that in this embodiment, the second terminal can determine the LCID that meets the preset conditions through various implementation manners, and use the LCID that meets the preset conditions as the input parameter for the second PDCP entity of the second terminal to execute the security algorithm, so as to perform security protection on the first data packet.

[0215] S404. The second terminal sends the first data packet after security protection to the first terminal.

[0216] S405. The first terminal receives the first data packet after security protection.

[0217] S406. The first PDCP entity of the first terminal parses the first data packet after security protection based on the second LCID.

[0218] Exemplarily, the first PDCP entity of the first terminal parses the first data packet after security protection based on the second LCID, including: the first PDCP entity of the first terminal decrypts and / or performs integrity verification on the first data packet based on the second LCID.

[0219] Exemplarily, since the second LCID that meets the preset conditions determined by the first terminal in step S402 is the same as the first LCID that meets the preset conditions determined by the second terminal. Therefore, when the first PDCP entity of the first terminal parses the first data packet based on the second LCID in step S406, since the second LCID is the same as the input parameter when the second terminal performs security protection on the first data packet, the first terminal can normally parse the first data packet.

[0220] It should be noted that the present application embodiment does not limit the execution order of the above steps S402 and steps S403 - S405. For example, step S402 can be executed before steps S403 - S405, can also be executed after steps S403 - S405, or can be executed at any time between steps S403 - S405. Figure 4 Only step S402 being executed before steps S403 - S405 is taken as an example for illustration.

[0221] It can be understood that when the second PDCP entity of the second terminal and the first PDCP entity of the first terminal are associated with multiple LCHs in the embodiment of the present application, the second terminal determines the first LCID that meets the preset conditions, and the first terminal determines the second LCID that meets the same preset conditions, and the first LCID and the second LCID are the same, so as to ensure the consistency of the input parameters when the corresponding PDCP entities of the second terminal and the first terminal execute the security algorithm. Therefore, the first terminal can normally parse the data packet after security protection sent by the second terminal, enabling the SL between the first terminal and the second terminal to communicate normally.

[0222] Exemplarily, an embodiment of the present application further provides a communication method, which corresponds to the second implementation manner in step S401 and the second implementation manner in step S402. As Figure 5 shown, the method includes steps S501 - S508.

[0223] S501. The second terminal determines a first LCID that meets the first preset condition.

[0224] It can be understood that the specific implementation manner of step S501 can refer to the second implementation manner in step S401, which will not be elaborated here.

[0225] S502. The second terminal sends first indication information to the first terminal.

[0226] The first indication information is used to instruct the first terminal to use the LCID that meets the first preset condition as an input parameter of the security algorithm of the first PDCP entity.

[0227] S503. The first terminal receives the first indication information.

[0228] S504. The first terminal determines a second LCID that meets the first preset condition based on the first indication information.

[0229] It can be understood that the specific implementation manner of step S504 can refer to the second implementation manner in step S402, which will not be elaborated here.

[0230] S505. The second terminal uses the first LCID as an input parameter of the security algorithm of the second PDCP entity to perform security protection on the first data packet.

[0231] S506. The second terminal sends the first data packet after security protection to the first terminal.

[0232] S507. The first terminal receives the first data packet after security protection.

[0233] S508. The first PDCP entity of the first terminal parses the first data packet after security protection based on the second LCID.

[0234] It can be understood that the specific implementation manners of the above steps S505 - S508 can refer to steps S403 - S406, which will not be elaborated here.

[0235] It should be noted that the present embodiment does not limit the execution order of the above steps S502 - S504 and steps S505 - S507. For example, step S502 can be executed before steps S505 - S507, after steps S505 - S507, or at any time between steps S505 - S507. Figure 5 Only taking the execution of steps S502 - S504 before steps S505 - S507 as an example for illustration.

[0236] It can be understood that in this embodiment, the second terminal autonomously determines the first LCID based on the sizes of the LCIDs corresponding to two or more LCHs associated with the second PDCP entity, and instructs the first terminal to use the LCID that meets the first preset condition as the input parameter of the security algorithm of the first PDCP entity by sending the first indication information to the first terminal. Thus, when the corresponding PDCP entities of the second terminal and the first terminal execute the security algorithm, the consistency of the input parameters can be ensured. Therefore, the first terminal can normally parse the security - protected data packet sent by the second terminal, enabling the SL between the first terminal and the second terminal to communicate normally.

[0237] Exemplarily, the embodiment of the present application further provides a communication method, which corresponds to the third implementation manner in step S401 and the second implementation manner in step S402, as Figure 6 shown, this method includes steps S601 - S611.

[0238] S601. The network device determines the first preset condition.

[0239] Exemplarily, the network device can be an access network device or a core network device, and the embodiment of the present application does not limit this.

[0240] Regarding the relevant content of the first preset condition, reference can be made to the relevant description in the foregoing step S401, and details will not be elaborated here.

[0241] S602. The network device sends the third indication information to the second terminal.

[0242] The third indication information is used to instruct the second terminal to use the LCID that meets the first preset condition as the input parameter of the security algorithm of the second PDCP entity.

[0243] The second PDCP entity of the second terminal is associated with two or more logical channels LCH.

[0244] S603. The second terminal receives the third indication information.

[0245] S604. The second terminal determines a first LCID that meets the first preset condition based on the third indication information.

[0246] It can be understood that the specific implementation manner of step S604 can refer to the third implementation manner in step S401, which will not be elaborated here.

[0247] S605. The second terminal sends the first indication information to the first terminal.

[0248] The third indication information is used to instruct the first terminal to use the first LCID that meets the first preset condition as the input parameter of the security algorithm of the first PDCP entity.

[0249] S606. The first terminal receives the first indication information.

[0250] S607. The first terminal determines a second LCID that meets the first preset condition based on the first indication information.

[0251] It can be understood that the specific implementation manner of step S607 can refer to the second implementation manner in step S402, which will not be elaborated here.

[0252] S608. The second terminal uses the first LCID as the input parameter of the security algorithm of the second PDCP entity to perform security protection on the first data packet.

[0253] S609. The second terminal sends the first data packet after security protection to the first terminal.

[0254] S610. The first terminal receives the first data packet after security protection.

[0255] S611. The first PDCP entity of the first terminal parses the first data packet after security protection based on the second LCID.

[0256] It can be understood that the specific implementation manners of the above steps S608 - S611 can refer to steps S403 - S�06, which will not be elaborated here.

[0257] It should be noted that this embodiment does not limit the execution order of the above steps S605 - S607 and steps S608 - S610. For example, step S605 can be executed before steps S608 - S610, can also be executed after steps S608 - S610, or can be executed at any time between steps S608 - S610. Figure 6 Only taking the case where steps S605 - S607 are executed before steps S608 - S610 as an example for illustration.

[0258] It can be understood that in this embodiment, the second terminal receives the third indication information sent by the network device, determines the first LCID that meets the first preset condition based on the third indication information, and by sending the first indication information to the first terminal, instructs the first terminal to use the LCID that meets the first preset condition as the input parameter of the security algorithm of the first PDCP entity, so that when the corresponding PDCP entities of the second terminal and the first terminal execute the security algorithm, the consistency of the input parameters can be ensured. Therefore, the first terminal can normally parse the security-protected data packet sent by the second terminal, enabling the SL between the first terminal and the second terminal to communicate normally.

[0259] Exemplarily, an embodiment of the present application further provides a communication method, which corresponds to the fifth implementation manner in step S401 and the fourth implementation manner in step S402, as Figure 7 shown, this method includes steps S701 - S708.

[0260] S701. The second terminal determines the first LCID that meets the second preset condition.

[0261] It can be understood that the specific implementation manner of step S701 can refer to the fifth implementation manner in step S401, which will not be elaborated here.

[0262] S702. The second terminal sends the second indication information to the first terminal.

[0263] The second indication information includes the first LCID, and is used to instruct the first terminal to use the first LCID as the input parameter of the security algorithm of the first PDCP entity. The first LCID is the LCID corresponding to the LCH determined by the second terminal that meets the second preset condition.

[0264] S703. The first terminal receives the second indication information.

[0265] S704. The first terminal determines the second LCID that meets the second preset condition based on the second indication information.

[0266] It can be understood that the specific implementation manner of step S704 can refer to the fourth implementation manner in step S402, which will not be elaborated here.

[0267] S705. The second terminal uses the first LCID as the input parameter of the security algorithm of the second PDCP entity to perform security protection on the first data packet.

[0268] S706. The second terminal sends the first data packet after security protection to the first terminal.

[0269] S707. The first terminal receives the first data packet after security protection.

[0270] The first PDCP entity of the first terminal parses the first data packet after security protection based on the second LCID.

[0271] It can be understood that the specific implementation manners of the above steps S705 - S708 can refer to steps S403 - S406, and will not be elaborated here.

[0272] It should be noted that this embodiment does not limit the order of execution of the above steps S702 - S704 and steps S705 - S707. For example, step S702 can be executed before steps S705 - S707, can be executed after steps S705 - S707, or can be executed at any time between steps S705 - S707. Figure 7 Only taking the case where steps S702 - S704 are executed before steps S705 - S707 as an example for illustration.

[0273] It can be understood that in this embodiment, the second terminal autonomously determines the first LCID based on the LCH configuration parameters of two or more LCHs associated with the second PDCP entity, and indicates to the first terminal to use this first LCID as the input parameter of the security algorithm of the first PDCP entity by sending the second indication information to the first terminal. Thus, when the corresponding PDCP entities of the second terminal and the first terminal execute the security algorithm, the consistency of the input parameters can be ensured. Therefore, the first terminal can normally parse the data packet after security protection sent by the second terminal, enabling the SL between the first terminal and the second terminal to communicate normally.

[0274] Exemplarily, an embodiment of the present application further provides a communication method, which corresponds to the sixth implementation manner in step S401 and the fourth implementation manner in step S402, as Figure 8 shown, this method includes steps S801 - S811.

[0275] S801. The network device determines a second preset condition.

[0276] Exemplarily, the network device can be an access network device or a core network device, and this embodiment of the present application does not limit this.

[0277] S802. The network device sends fourth indication information to the second terminal.

[0278] The fourth indication information includes target LCH configuration parameters, and is used to indicate the second terminal to use the LCID that meets the second preset condition as the input parameter of the security algorithm of the second PDCP entity of the second terminal, and the LCID that meets the second preset condition is the LCID corresponding to the target LCH configuration parameters.

[0279] The second PDCP entity of the second terminal is associated with two or more logical channels LCH.

[0280] S803. The second terminal receives fourth indication information.

[0281] S804. The second terminal determines a first LCID that meets the second preset condition based on the fourth indication information.

[0282] It can be understood that the specific implementation manner of step S804 can refer to the sixth implementation manner in step S401, which will not be elaborated here.

[0283] S805. The second terminal sends second indication information to the first terminal.

[0284] The second indication information includes the first LCID, and the second indication information is used to instruct the first terminal to use the first LCID as an input parameter of the security algorithm of the first PDCP entity. The first LCID is the LCID corresponding to the LCH determined by the second terminal that meets the second preset condition.

[0285] S806. The first terminal receives the second indication information.

[0286] S807. The first terminal determines a second LCID that meets the second preset condition based on the second indication information.

[0287] It can be understood that the specific implementation manner of step S807 can refer to the fourth implementation manner in step S402, which will not be elaborated here.

[0288] S808. The second terminal uses the first LCID as an input parameter of the security algorithm of the second PDCP entity to perform security protection on the first data packet.

[0289] S809. The second terminal sends the first data packet after security protection to the first terminal.

[0290] S810. The first terminal receives the first data packet after security protection.

[0291] S811. The first PDCP entity of the first terminal parses the first data packet after security protection based on the second LCID.

[0292] It can be understood that the specific implementation manners of the above steps S808 - S811 can refer to steps S403 - S406, which will not be elaborated here.

[0293] It should be noted that this embodiment does not limit the execution order of the above steps S805 - S807 and steps S808 - S810. For example, step S805 can be executed before steps S808 - S810, after steps S808 - S810, or at any time between steps S808 - S810. Figure 8 Only taking the execution of steps S805 - S807 before steps S808 - S810 as an example for illustration.

[0294] It can be understood that in this embodiment, the second terminal receives the fourth indication information sent by the network device, determines the first LCID that meets the second preset condition based on the fourth indication information, and instructs the first terminal to use the first LCID as the input parameter of the security algorithm of the first PDCP entity by sending the second indication information to the first terminal. Thus, when the corresponding PDCP entities of the second terminal and the first terminal execute the security algorithm, the consistency of the input parameters can be ensured. Therefore, the first terminal can correctly parse the security - protected data packet sent by the second terminal, enabling the SL between the first terminal and the second terminal to communicate normally.

[0295] Exemplarily, when the input parameter of the security algorithm is the SLRB ID, for the SL - Data Radio Bearer (DRB), the transceiver UEs can align the SLRB ID corresponding to the SL - DRB through PC5 - RRC interaction. For the SL - Signaling Radio Bearer (SRB), most of the SL - SRBs carrying PC5 - S messages are sent before the PC5 - RRC message. Therefore, it may not be possible to let the PDCP entities of the second terminal and the first terminal know the SLRB ID of the SL - SRB through the PC5 - RRC message to correctly execute the security algorithm.

[0296] To solve the problem that when the input parameter of the security algorithm is the SLRB ID, for the PDCP entity corresponding to the SL - SRB to execute the security protection algorithm, the transceiver UEs may not be able to know the SLRB ID corresponding to the SL - SRB through the PC5 - RRC message, resulting in the SL - SRB not supporting security protection. The embodiment of the present application provides a communication method, as Figure 9 shown, the method includes steps S901 - S904.

[0297] S901. The second terminal uses the first SLRB ID as the input parameter of the security algorithm to perform security protection on the first data packet.

[0298] Exemplarily, the second terminal uses the first SLRB ID as an input parameter of the security algorithm to perform security protection on the first data packet, including: the second terminal uses the first SLRB ID as an input parameter of the security algorithm to encrypt and / or perform integrity protection on the first data packet.

[0299] S902. The second terminal sends the first data packet after security protection to the first terminal.

[0300] The first SLRB ID is carried in the first data packet.

[0301] Exemplarily, the first SLRB ID is carried in the header of the first data packet. For example, the first SLRB ID is carried in the PDCP header of the first data packet.

[0302] S903. The first terminal receives the first data packet after security protection.

[0303] S904. The first terminal analyzes the first data packet based on the first SLRB ID.

[0304] Exemplarily, since the first SLRB ID is carried in the header of the first data packet, when the first terminal receives the first data packet at the PDCP layer, it can determine that the input parameter of the security algorithm corresponding to the PDCP entity is the first SLRB ID according to the first SLRB ID carried in the header of the data packet. Thus, the corresponding PDCP entities in the second terminal and the first terminal can use the same SLRB ID as the input parameter to ensure that the data transmission on the SL between the second terminal and the first terminal can be protected by the security algorithm.

[0305] It can be understood that the above methods of S901 - S904 are not only applicable to the security protection of data packets corresponding to SL - SRB, but also applicable to the security protection of data packets corresponding to SL - DRB.

[0306] It can be understood that in this embodiment, the second terminal uses the first SLRB ID as an input parameter of the security algorithm to perform security protection on the first data packet, and sends the first data packet carrying the first SLRB ID to the first terminal. Thus, after the first terminal receives the first data packet, it can analyze the first data packet based on the first SLRB ID carried in the header of the first data packet. Therefore, the second terminal and the first terminal can use the same SLRB ID as the input parameter to ensure that the data transmission on the SL between the second terminal and the first terminal can be protected by the security algorithm.

[0307] When the input parameter of the security algorithm is the SLRB ID, the PDCP entity corresponding to the SL-SRB executes the security protection algorithm, and the sending and receiving UEs may not be able to obtain the SLRB ID corresponding to the SL-SRB through the PC5-RRC message, resulting in the problem that the SL-SRB cannot support security protection. An embodiment of the present application also provides a communication method, as Figure 10 shown, the method includes: S1001-S1006.

[0308] S1001. The second terminal sends a first message to the first terminal.

[0309] The first SLRB ID is carried in the first message.

[0310] Exemplarily, the first message is a PC5-S message. The above first SLRB ID is carried in the PC5-S message. The PC5-S message may be a message during the PC5-S connection establishment process between the second terminal and the first terminal. The first SLRB ID is the SRB ID corresponding to the SRB that carries the second message after the first message.

[0311] Exemplarily, in this embodiment, the SLRB ID information indicating the SRB may directly indicate the SLRB ID corresponding to SRBX, or may indicate the SLRB ID corresponding to the LCID. The embodiments of the present application do not limit this. The following embodiments only take the SLRB ID indicating the SRB as the SLRB ID corresponding to SRBX as an example for illustration.

[0312] For example, the messages during the PC5-S connection establishment process may include Message 1 to Message 4. Among them, Message 1 is a connection establishment request message sent by the second terminal to the first terminal; Message 2 is a security activation command message sent by the first terminal to the second terminal; Message 3 is a security activation completion message fed back by the second terminal to the first terminal; Message 4 is a PC5-S connection establishment acceptance message fed back by the first terminal to the second terminal.

[0313] For example, SRB0 is used to carry PC5-S messages without security protection (for example, Message 1 during PC5-S connection establishment), SRB1 is used to carry PC5-S messages related to security activation (for example, Message 2 and Message 3 during PC5-S connection establishment), SRB2 is used to carry PC5-S messages with security protection (for example, Message 4 during PC5-S connection establishment), and SRB3 is used to carry PC5-RRC messages. The embodiments of the present application do not limit the specific number of SL-SRBs carrying PC5-S messages and PC5-RRC messages, nor the specific SRBX carried by each message. This is only an exemplary illustration here.

[0314] It can be understood that the above first message can be any one of Messages 1-4 in the PC5-S connection establishment process. Taking the first message as Message 1 as an example, the second message can be a PC5-S message or a PC5-RRC message after Message 1.

[0315] Exemplarily, as Figure 11 shown, the second terminal can carry the SRB ID corresponding to the SRB carrying the PC5-S message and the PC5-RRC message after Message 1 in Message 1, and send the first message to the first terminal. That is to say, the second terminal can send the SRB ID corresponding to the SRB carrying the PC5-S message and the PC5-RRC message after Message 1 to the first terminal at one time in Message 1.

[0316] Exemplarily, as Figure 12 shown, the second terminal can also carry the SRB ID corresponding to the SRB carrying Message 2 in Message 1, and send the first message to the first terminal. That is to say, the second terminal can only send the SRB ID corresponding to the SRB carrying one or more messages after Message 1 to the first terminal.

[0317] The embodiments of the present application do not limit the SRB ID carried in the first message for the specific message after the first message. The above Figure 11 and Figure 12 are only exemplary illustrations.

[0318] S1002. The first terminal receives the first message.

[0319] Exemplarily, when the first terminal receives the first message, it can obtain the SRB ID corresponding to the SRB carrying the second message.

[0320] S1003. The first terminal performs security protection on the second message based on the first SLRB ID.

[0321] Exemplarily, the first terminal performs security protection on the second message based on the first SLRB ID, including: the first terminal uses the first SLRB ID as an input parameter of the security algorithm to encrypt and / or perform integrity protection on the second message.

[0322] Exemplarily, the second message can be a PC5-S message or a PC5-RRC message. It should be noted that the second message is a message after the first message. That is to say, the second terminal can send the SRB ID carrying the second message to the first terminal in advance, so that the first terminal can perform security protection on the second message based on the SRB ID carrying the second message.

[0323] For example, when the first message is Message 1, the second message can be Message 2, Message 4, or a PC5-RRC message. When the second message is Message 2, the first SLRB ID carried in the first message includes the SRB ID corresponding to the SRB carrying Message 2. That is, the first SLRB ID carried in Message 1 includes the SRB1 ID.

[0324] It should be noted that the SRB IDs corresponding to the SRBs carrying PC5-S messages and PC5-RRC messages can all be determined by the second terminal, or jointly determined by the second terminal and the first terminal (for example, the SRB1 ID is determined by the second terminal, and the SRB2 ID and SRB3 ID are determined by the first terminal). This application does not limit this. This embodiment only takes the example that the SRB ID corresponding to the SRB carrying the second message is determined by the second terminal for illustration.

[0325] S1004. The first terminal sends the second message after security protection to the second terminal.

[0326] S1005. The second terminal receives the second message after security protection.

[0327] S1006. The second terminal analyzes the second message based on the first SLRB ID.

[0328] Exemplarily, in this embodiment, the first SLRB ID is determined by the second terminal, and the second terminal can analyze the second message after security protection sent by the first terminal based on this first SLRB ID.

[0329] In this embodiment, the second terminal sends the first message carrying the first SLRB ID to the first terminal, and the first SLRB ID is the SRB ID corresponding to the SRB carrying the second message, so that the first terminal can perform security protection on the second message based on this first SLRB ID. The second terminal receives the second message after security protection from the first terminal and analyzes the second message based on the first SLRB ID. That is, in this embodiment, the second terminal sends the first SLRB ID corresponding to the SRB carrying the second message to the first terminal in advance, so that the first terminal knows the input parameters for performing security protection on the second message, thereby ensuring that the input parameters for the first terminal to perform security protection on the second message are consistent with the input parameters for the second terminal to analyze the second message. Therefore, the transmission on the SL between the second terminal and the first terminal can achieve the protection of the security algorithm.

[0330] Exemplarily, when the above-mentioned second message is Message 3 or a PC5-RRC message, in step S1003, the first terminal may perform secure parsing of the second message based on the first SLRB ID. In this implementation manner, after the above-mentioned steps S1001 - S1002, the second terminal may also perform security protection on the second message based on the first SLRB and send the securely protected second message to the first terminal. After receiving the second message, the first terminal may perform secure parsing of the second message based on the first SLRB. That is to say, by the second terminal sending the first SLRB to the first terminal in advance, so that after receiving the securely protected second message, the first terminal can parse the second message based on this first SLRB. For example, as Figure 11 shown, the second terminal carries the SRB1 ID, SRB2 ID, and SRB3 ID in Message 1. The second terminal may perform security protection on Message 3 based on the SRB1 ID and send the securely protected Message 3 to the first terminal. The first terminal receives Message 3 and parses Message 3 based on the SRB1 ID carried in Message 1.

[0331] It should be noted that when the SRB ID corresponding to the SRB carrying the second message is determined by the first terminal, the first terminal may send the SRB ID corresponding to the SRB carrying the second message to the second terminal in advance, so that the second terminal performs security protection on the second message based on this SRB ID, ensuring that the input parameters for the second terminal to perform security protection on the second message are consistent with the input parameters for the first terminal to parse the second message. Therefore, the data transmission on the SL between the second terminal and the first terminal can achieve the protection of the security algorithm.

[0332] The above mainly introduces the solution provided in the embodiments of the present application from the perspective of method steps. It can be understood that in order for a computer to implement the above functions, it includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, combining the modules and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of a combination of hardware and computer software. Professional technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0333] The embodiments of the present application may perform functional module division on the computer according to the above method examples. For example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The above integrated module may be implemented in the form of hardware or in the form of a software functional module. It should be noted that the division of modules in the embodiments of the present application is illustrative, only a logical functional division, and there may be other division methods in actual implementation.

[0334] In the case where each functional module is divided corresponding to each function, [[ID= FIG. shows a schematic structural diagram of a communication device 1300. The communication device 1300 may be the second terminal in the above embodiment, or may also be a chip in the second terminal. The communication device 1300 includes: a processing unit 1301 and a transceiver unit 1302.

[0335] Among them, the processing unit 1301 may execute, for example, ​ S401 and S403 in, or ​ S501 and S505 in, or ​ S604 and S608 in, or ​ S701 and S705 in, or ​ S804 and S808 in, or ​ S901 in, or ​ S1006 in; the transceiver unit 1302 may execute, for example, ​ S404 in, or ​ S502 and S506 in, or ​ S603, S605 and S609 in, or ​ S702 and S706 in, or ​ S803, S805 and S809 in, or ​ S902 in, or ​ S1001 and S1005 in. It can be understood that the above processing unit 1301 can also send and receive information through the transceiver unit 1302, or be used for communicating with other network elements, and / or be used for other processes of the technologies described in this article. Among them, all relevant contents of each step involved in the above method embodiments can be cited in the function descriptions of the corresponding functional modules, and will not be elaborated here.

[0336] In the case where each functional module is divided corresponding to each function, ​ FIG. shows a schematic structural diagram of a communication device 1400. The communication device 1400 may be the first terminal in the above embodiment, or may also be a chip in the first terminal. The communication device 1400 includes: a processing unit 1401 and a transceiver unit 1402.

[0337] Among them, the processing unit 1401 may execute, for example, ​ S402 and S406 in, or ​ S504 and S508 in, or ​ S607 and S611 in, or ​ S704 and S708 in, or ​ S807 and S811 in, or​ S904 in ​ or S1003 in ​ The transceiver unit 1402 may execute, for example, S405 in ​ or S503 and S507 in ​ or S606 and S610 in ​ or S703 and S707 in ​ or S806 and S810 in ​ or S903 in ​ or S1002 and S1004 in

[0338] In the case of dividing each function into corresponding function modules, ​ FIG. shows a schematic structural diagram of a communication device 1500. The communication device 1500 may be the network device in the above embodiment, or may be a chip in the above network device. The communication device 1500 includes: a processing unit 1501 and a transceiver unit 1502.

[0339] Among them, the processing unit 1501 may execute ​ S601 in ​ or S801 in ​ The transceiver unit 1502 may execute S602 in ​ or S802 in

[0340] In the case of adopting an integrated unit, ​ FIG. shows a possible schematic structural diagram of the second terminal involved in the above embodiment. The second terminal 1600 includes: a processor 1601 and a transceiver 1602.

[0341] Among them, the processor 1601 is used to control and manage the actions of the second terminal 1600. For example, the processor 1601 may execute ​ S401 and S40, or, ​ S501 and S505 in ​S604 and S608 in, or, ​ S701 and S705 in, or, ​ S804 and S808 in, or, ​ S901 in, or, ​ S1006 in, and / or other processes for the technologies described herein.

[0342] The transceiver 1602 is used to send and receive information, or to communicate with other network elements. For example, the transceiver 1602 can execute ​ S404 in, or, ​ S502 and S506 in, or, ​ S603, S605 and S609 in, or, ​ S702 and S706 in, or, ​ S803, S805 and S809 in, or, ​ S902 in, or, ​ S1001 and S1005 in, and / or other processes for the technologies described herein.

[0343] Optionally, the second terminal 1600 may further include a memory 1603, which is used to store the program codes and data corresponding to any communication method provided above executed by the second terminal 1600. The memory 1603 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM), etc. The second terminal 1600 may be ​ the communication device shown above, and all the relevant content descriptions of the above ​ involved components can be cited to ​ the function descriptions of the corresponding components, which will not be elaborated here.

[0344] In the case of adopting an integrated unit, ​ shows a possible structural schematic diagram of the first terminal 1700 involved in the above embodiments. The first terminal 1700 includes: a processor 1701 and a transceiver 1702.

[0345] Among them, the processor 1701 is used to control and manage the actions of the first terminal 1700. For example, the processor 1701 can execute ​ S402 and S406 in, or, ​ S504 and S508 in, or, ​ S607 and S611 in, or, ​ S704 and S708 in, or,​ S807 and S811 in ​ S904 in ​ S1003 in

[0346] The transceiver 1702 is used to send and receive information, or to communicate with other network elements. For example, the transceiver 1702 can execute ​ S405 in ​ S503 and S507 in ​ S606 and S610 in ​ S703 and S707 in ​ S806 and S810 in ​ S903 in ​ S1002 and S1004 in

[0347] Optionally, the first terminal 1700 may further include a memory 1703, which is used to store the program codes and data corresponding to any communication method provided above executed by the first terminal 1700. The memory 1703 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM), etc. The first terminal 1700 may be ​ the communication device shown in ​ All relevant descriptions of the components involved above can be cited to ​ the function descriptions of the corresponding components, which will not be elaborated here.

[0348] In the case of adopting an integrated unit, ​ FIG. shows a possible structural schematic diagram of the network device 1800 involved in the above embodiments. The network device 1800 includes: a processor 1801 and a transceiver 1802.

[0349] Among them, the processor 1801 is used to control and manage the actions of the network device 1800. For example, the processor 1801 can execute ​ S601 in ​ S801 in

[0350] The transceiver 1802 is used to send and receive information, or to communicate with other network elements. For example, the transceiver 1802 can execute ​ S602 in ​S802 in, and / or other processes for the techniques described herein.

[0351] Optionally, the network device 1800 may further include a memory 1803 for storing program codes and data corresponding to any of the communication methods provided above for the network device 1800 to execute. The memory 1803 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM), etc. The network device 1800 may be ​ the communication device shown above, and all relevant descriptions of the various components involved above may be cited to ​ the function description of the corresponding component, which will not be elaborated here. ​

[0352] An embodiment of the present application further provides a communication device, which includes a processor, and may further include a transceiver and a memory. The transceiver is used to send and receive information, or to communicate with other network elements; the memory is used to store computer execution instructions; the processor is used to execute the computer execution instructions to support the terminal device to implement ​ the communication method in any of the embodiments in

[0353] An embodiment of the present application further provides a communication device, which includes a processor, and may further include a transceiver and a memory. The transceiver is used to send and receive information, or to communicate with other network elements; the memory is used to store computer execution instructions; the processor is used to execute the computer execution instructions to support the network device to implement ​ or ​ the communication method in any of the embodiments.

[0354] An embodiment of the present application further provides a computer-readable storage medium, in which computer program codes are stored. When the above processor executes the computer program codes, the electronic device executes ​ the communication method in any of the embodiments in

[0355] An embodiment of the present application further provides a computer program product. When the computer program product runs on a computer, it causes the computer to execute ​ the communication method in any of the embodiments in

[0356] An embodiment of the present application further provides a communication device, which may exist in the form of a chip product. The structure of the device includes a processor and an interface circuit. The processor is used to communicate with other devices through a receiving circuit, so that the device executes the above ​ the communication method in any of the embodiments in​

[0357] An embodiment of the present application further provides a communication system, including a second terminal and a first terminal, and the second terminal and the first terminal can execute the communication method in any of the above ​ embodiments.

[0358] The steps of the method or algorithm described in combination with the disclosed content of the present application can be implemented in a hardware manner or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in a random access memory (RAM), flash memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), register, hard disk, removable hard disk, read-only optical disc (CD-ROM), or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in a core network interface device. Of course, the processor and the storage medium can also exist as discrete components in the core network interface device.

[0359] Those skilled in the art should be able to realize that in one or more of the above examples, the functions described in the present application can be implemented by hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. The computer-readable medium includes a computer-readable storage medium and a communication medium, where the communication medium includes any medium facilitating the transmission of a computer program from one place to another. The storage medium can be any available medium accessible by a general-purpose or special-purpose computer.

[0360] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present application. It should be understood that the above is only the specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solution of the present application should be included in the protection scope of the present application.

Claims

1. A communication method, characterized in that, Applied to the first terminal or the chip in the first terminal, the method includes: Receiving a first data packet from a second terminal, where the first data packet is a data packet obtained by the second PDCP entity of the second terminal after performing security protection on a logical channel identifier (LCID) that meets a preset condition, and the first packet data convergence protocol (PDCP) entity of the first terminal is associated with two or more logical channels (LCHs); The first PDCP entity of the first terminal parsing the first data packet based on the LCID.

2. The method according to claim 1, characterized in that, The preset condition includes a first preset condition, and the size of the LCID meets the first preset condition.

3. The method according to claim 2, wherein Determining the logical channel identifier (LCID) that meets the preset condition includes: Based on a preset rule, determining the LCID that meets the first preset condition, where the preset rule is predefined.

4. The method according to claim 2, wherein The method further includes: Receiving first indication information from the second terminal, where the first indication information is used to instruct the first terminal to use the LCID that meets the first preset condition as an input parameter of the security algorithm of the first PDCP entity.

5. The method according to claim 4, wherein Determining the logical channel identifier (LCID) that meets the preset condition includes: Based on the first indication information, determining the LCID that meets the first preset condition.

6. The method according to claim 4 or 5, characterized in that The first indication information is carried in first sidelink radio bearer (SLRB) configuration information, and the first SLRB configuration information is carried in a PC5-radio resource control (RRC) message.

7. The method according to any one of claims 2-5, characterized in that, The LCID that meets the first preset condition is the smallest LCID or the largest LCID among the LCIDs corresponding to the two or more LCHs.

8. The method according to claim 1, wherein The preset condition includes a second preset condition, and the configuration parameters of the LCH corresponding to the LCID meet the second preset condition.

9. The method according to claim 8, wherein The method further includes: Receiving second indication information from the second terminal, where the second indication information includes a target LCID, and the second indication information is used to instruct the first terminal to use the target LCID as an input parameter of the security algorithm of the first PDCP entity, and the target LCID is the LCID corresponding to the LCH determined by the second terminal to meet the second preset condition.

10. The method according to claim 9, wherein Determining the logical channel identifier (LCID) that meets the preset condition includes: Based on the second indication information, determining the LCID that meets the second preset condition.

11. The method according to claim 9 or 10, characterized in that, The second indication information is carried in second SLRB configuration information, and the second SLRB configuration information is carried in a PC5-RRC message.

12. A communication method, characterized in that, Applied to the second terminal or the chip in the second terminal, the method includes: Using the logical channel identifier (LCID) that meets the preset condition as an input parameter of the security algorithm of the second PDCP entity to perform security protection on a first data packet, where the second packet data convergence protocol (PDCP) entity of the second terminal is associated with two or more logical channels (LCHs); Send the first data packet after security protection to the first terminal; wherein, the LCID is an input parameter when the first PDCP entity of the first terminal parses the first data packet, and the first PDCP entity of the first terminal corresponds to the second PDCP entity of the second terminal.

13. The method according to claim 12, wherein The preset condition includes a first preset condition, and the size of the LCID meets the first preset condition.

14. The method according to claim 13, characterized in that, The determining the logical channel identifier LCID that meets the preset condition includes: Based on a preset rule, determine the LCID that meets the first preset condition, and the preset rule is predefined.

15. The method according to claim 13, wherein The determining the logical channel identifier LCID that meets the preset condition includes: Based on the sizes of the LCIDs corresponding to the two or more LCHs, determine the LCID that meets the first preset condition.

16. The method according to claim 13, wherein The method further includes: Receive third indication information from a network device, where the third indication information is used to instruct the second terminal to use the LCID that meets the first preset condition as an input parameter of the security algorithm of the second PDCP entity.

17. The method according to claim 16, wherein The determining the logical channel identifier LCID that meets the preset condition includes: Based on the third indication information, determine the LCID that meets the first preset condition.

18. The method according to claim 16 or 17, characterized in that, The third indication information further includes the identification information of the first terminal.

19. The method according to claim 16 or 17, characterized in that, The third indication information is carried in the third sidelink radio bearer SLRB configuration information, and the third SLRB configuration information is carried in a radio resource control RRC message, a system information block SIB, or a preconfigured message.

20. The method according to any one of claims 15 - 17, characterized in that, The method further includes: Send first indication information to the first terminal, where the first indication information is used to instruct the first terminal to use the LCID that meets the first preset condition as an input parameter of the security algorithm of the first PDCP entity of the first terminal.

21. The method according to claim 20, characterized in that, The first indication information is carried in the first sidelink radio bearer SLRB configuration information, and the first SLRB configuration information is carried in a PC5-RRC message.

22. The method according to any one of claims 13-17, characterized in that, The LCID that meets the first preset condition is the smallest LCID or the largest LCID among the LCIDs corresponding to the two or more LCHs.

23. A communication method, characterized in that, Applied to a network device or a chip in the network device, the method includes: Send indication information to a second terminal, where the indication information is used to instruct the second terminal to use the logical channel identifier LCID that meets the preset condition as an input parameter of the security algorithm of the second packet data convergence protocol PDCP entity of the second terminal, and the second PDCP entity of the second terminal is associated with two or more logical channels LCHs.

24. The method according to claim 23, wherein, The preset condition includes a first preset condition, and the size of the LCID meets the first preset condition; the indication information includes third indication information, and the third indication information is used to instruct the second terminal to use the LCID that meets the first preset condition as an input parameter of the security algorithm of the second PDCP entity of the second terminal.

25. The method according to claim 23, characterized in that, The preset conditions include a second preset condition, and the configuration parameters of the LCH corresponding to the LCID meet the second preset condition; the indication information includes fourth indication information, and the fourth indication information is used to indicate the second terminal to use the LCID that meets the second preset condition as the input parameter of the security algorithm of the second PDCP entity of the second terminal.

26. The method according to claim 25, characterized in that, The fourth indication information further includes target LCH configuration parameters, and the LCID that meets the second preset condition is the LCID corresponding to the target LCH configuration parameters.

27. The method according to any one of claims 23-26, characterized in that, The indication information is carried in the sidelink radio bearer (SLRB) configuration information, and the SLRB configuration information is carried in a radio resource control (RRC) message, a system information block (SIB), or a preconfigured message.

28. A communication device, characterized in that, The device includes: a processor, configured to execute instructions to implement the communication method according to any one of claims 1-27.

29. A communication device, characterized in that, It includes units for executing the communication method according to any one of claims 1-27.

30. A computer-readable storage medium storing computer program code, characterized in that, When the computer program code runs on the processor, the processor is caused to execute the communication method according to any one of claims 1-27.

31. A communication device, characterized in that, The communication device includes: a transceiver, configured to transmit and receive information, or configured to communicate with other network elements; a processor, configured to execute computer program instructions to implement the communication method according to any one of claims 1-27.

32. A computer program product storing computer software instructions executable by a processor, characterized in that, When the computer software instructions run on the computer, the computer is caused to execute the communication method according to any one of claims 1-27.

33. A communication system, characterized in that, The communication system includes: a first terminal, a second terminal, and a network device. The first terminal is configured to execute the communication method according to any one of claims 1-11, the second terminal is configured to execute the communication method according to any one of claims 12-22, and the network device is configured to execute the communication method according to any one of claims 23-27.

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