WO2022133912A1

WO2022133912A1 - Sidelink communication method, apparatus and system

Info

Publication number: WO2022133912A1
Application number: PCT/CN2020/139044
Authority: WO
Inventors: 王南鑫; 彭文杰
Original assignee: 华为技术有限公司
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2022-06-30

Abstract

Disclosed in the present application are a sidelink communication method, apparatus and system, applied to the field of mobile communication. The method comprises: a first terminal device determines that PDCP COUNT of a first bearer is about to be rolled over, and that the first bearer is a sidelink bearer initiated and established by the first terminal device with a second terminal device; and the first terminal device initiates a bearer modification process or a key update process for the first bearer with the second terminal device. The method can solve the problem that different data packets use the same security input parameter, can avoid security risks caused by security reduction, and compared with a method of deleting the first bearer and adding a bearer, can avoid the problem of causing large transmission interruption and loss of data packets.

Description

Sidelink communication method, apparatus and system

technical field

The present application relates to the field of mobile communication technologies, and in particular, to a sidelink communication method, apparatus and system.

Background technique

The terminal device can communicate with the terminal device through the network, and can also communicate directly. Sidelink (SL) communication is a direct communication technology between terminal equipment and terminal equipment formulated by the 3rd Generation Partnership Project (3GPP). Data transmission can be directly performed between the terminal equipment and the terminal equipment through the side link without going through the network, which can effectively reduce the communication delay. In SL communication, data is transmitted between two terminal devices through the PC5 interface. The typical application of SL communication is the Vehicle to Everything (V2X) scenario. In the V2X scenario, a vehicle is a terminal device. In addition to V2X scenarios, SL communication can also be used in other scenarios, such as direct communication between wearable devices. In order to ensure the communication security at both ends of the communication, the data communicated between the two terminal devices needs to be secured.

However, the inventors of the present application have found that the problem of reduced security of communication between two terminal devices may currently occur.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a sidelink communication method, apparatus, and system. According to the technical solution provided by the present application, the first terminal device determines that the PDCP COUNT of the first bearer is about to be reversed, and the first bearer is initiated by the first terminal device. The established sidelink bearer with the second terminal device, the first terminal device initiates a bearer modification process or a key update process for the first bearer between the first terminal device and the second terminal device, so that different data packets can be resolved The problem of using the same security input parameters can avoid the security risk caused by the reduction of security. Compared with the method of deleting the first bearer and adding another bearer, the problem of causing a larger transmission interruption and loss of data packets can be avoided.

In a first aspect, a communication method is provided. It can be understood that the method of the first aspect may be performed by a first apparatus, and the first apparatus may be a communication device or a communication device capable of supporting the functions required by the communication device to implement the method, such as a chip system. Exemplarily, the communication device may be the first terminal device. The following description will be given by taking the implementation of the method by the first terminal device as an example.

The method includes: the first terminal device determines that the PDCP COUNT of the first bearer is about to be reversed, the first bearer is a side link bearer between the first terminal device and the second terminal device initiated and established, and the first terminal device initiates and establishes a side link bearer with the second terminal device. A bearer modification process or a key update process for the first bearer between the second terminal devices. The method provided by the first aspect solves the problem that different data packets use the same security input parameters, and can avoid security risks caused by security reduction. Compared with the method of deleting the first bearer and adding another bearer, it can Avoid problems that cause large transmission interruptions and packet loss.

It should be noted that the PDCP COUNT of the first bearer is about to be reversed, which may be that the PDCP COUNT of the first bearer maintained by the first terminal device as the sender is about to be reversed, or it may be the first terminal device maintained as the receiver. The carried PDCP COUNT is about to be rolled over, or both of them are about to roll over.

In a possible implementation manner of the first aspect, the first terminal device receives a first message from the second terminal device, where the first message includes first indication information, and the first indication information indicates the PDCP of the first bearer The COUNT is about to be rolled over, and the first terminal device determines, based on the first indication information, that the PDCP COUNT of the first bearer is about to roll over.

In a possible implementation manner of the first aspect, the PDCP layer of the first terminal device recognizes that the PDCP COUNT of the first bearer is about to be reversed, and the PDCP layer of the first terminal device reports to the RRC layer of the first terminal device the second indication information, the second indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over, and the RRC layer of the first terminal device determines that the PDCP COUNT of the first bearer is about to roll over based on the second indication information.

In a possible implementation manner of the first aspect, the PDCP layer of the first terminal device periodically reports the maintained PDCP COUNT of the first bearer to the RRC layer of the first terminal device according to a first period, and the first terminal device The RRC layer identifies whether the PDCP COUNT is about to rollover. The duration of the first cycle may be configured by the RRC layer of the first terminal device to the PDCP layer of the first terminal device, or may be determined by the PDCP layer itself.

It should be noted that the PDCP layer or the RRC layer of the first terminal device may determine or recognize that the PDCP COUNT is about to be flipped according to a first rule, and the first rule may be, for example, that the HFN in the PDCP COUNT value reaches the maximum value, or the HFN The highest bit becomes 1, or the PDCP COUNT value reaches the first threshold value, etc. This embodiment of the present application does not limit the first rule. It can be understood that the first rule may be determined by the first terminal device itself, may also be specified by a standard protocol, may be determined through negotiation between the first terminal device and the second terminal device, or may be determined by the network The device configuration is also not limited in this embodiment of the present application.

In a possible implementation manner of the first aspect, the first terminal device initiates a bearer modification process with the second terminal device for the first bearer, including: the first terminal device judging whether there is an available logical channel identifier, The available logical channel identifier is the logical channel identifier that has not been used together with the current key. When it is determined that there is an available logical channel identifier, the first terminal device sends a second message to the second terminal device, and the second message includes the first The bearer identifier of the bearer and the first logical channel identifier, and the second message is used to modify the logical channel identifier of the first bearer to the first logical channel identifier. With the method in this implementation, it is not necessary to delete the first bearer, and the buffered data packets will not be discarded during the bearer modification process. Compared with the method of deleting the first bearer and adding another bearer, it is possible to avoid causing large transmission interruptions and data packets. Missing question.

Optionally, the second message may only be used to modify the logical channel identifier of the first bearer without modifying other parameters of the first bearer, and the original configuration of the first bearer except the logical channel identifier continues to be used.

Optionally, in the bearer modification process for the first bearer, the PDCP entity of the first bearer may not be re-established, and the PDCP COUNT of the first bearer maintained by the first terminal device and the second terminal device may continue to be used without being re-established. Set to 0, so that the data transmission is less affected, and there will be no problems such as packet loss.

Optionally, in the bearer modification process for the first bearer, the PDCP entity of the first bearer may also be re-established, and the PDCP COUNT of the first bearer maintained by the first terminal device and the second terminal device is reset to 0, thereby The implementation complexity is reduced.

In a possible implementation manner of the first aspect, the first terminal device initiates a key update process with the second terminal device, including: the RRC layer of the first terminal device to the PC5-S layer of the first terminal device Reporting third indication information, where the third indication information is used to request key update. The PC5-S layer of the first terminal device initiates a key update process with the second terminal device based on the third indication information.

Optionally, the first terminal device determines whether there is an available logical channel identifier, the available logical channel identifier is a logical channel identifier that has not been used with the current key, and when it is determined that there is no available logical channel identifier, the first The RRC layer of the terminal device reports the third indication information to the PC5-S layer of the first terminal device.

Optionally, the third indication information includes a cause value, and the cause value may be used to indicate that the PDCP COUNT is overturned or that there is no available logical channel identifier.

In a second aspect, a communication method is provided. It can be understood that the method of the second aspect may be performed by a second apparatus, and the second apparatus may be a communication device or a communication device capable of supporting the functions required by the communication device to implement the method, such as a chip system. Exemplarily, the communication device may be the second terminal device. The following description will be given by taking the implementation of the method by the second terminal device as an example.

The method includes: the second terminal device receives a second message from the first terminal device, the second message includes a bearer identifier of the first bearer and a first logical channel identifier, and the second message is used to modify the logical channel identifier of the first bearer is the first logical channel identifier, the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established, and the second terminal device modifies the logical channel identifier of the first bearer based on the second message to The first logical channel identifier. Through the method provided in the second aspect, the PDCP COUNT carried by a sidelink is about to be reversed, and the terminal device that initiates the establishment of the sidelink bearer solves the problem of possible reduction in security, which can reduce the complexity, Reduce the impact on data transfer.

Optionally, before the second terminal device receives the second message from the first terminal device, the second terminal device determines that the PDCP COUNT of the first bearer is about to be reversed, and the first bearer is initiated by the first terminal device and established with the second terminal device. A side link between terminal devices is carried, and the second terminal device sends a first message to the first terminal device, where the first message includes first indication information, and the first indication information indicates that the PDCP COUNT of the first bearer is about to be reversed . Therefore, the first terminal device can be informed that the PDCP COUNT of the first bearer is about to be reversed and initiate a bearer modification process or a key update process for the first bearer, thereby avoiding security risks caused by security reduction.

In a possible implementation manner of the second aspect, the PDCP layer of the second terminal device recognizes that the PDCP COUNT of the first bearer is about to be flipped, and the PDCP layer of the second terminal device reports the second terminal device to the RRC layer of the second terminal device. indication information, the second indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over, and the RRC layer of the second terminal device determines that the PDCP COUNT of the first bearer is about to roll over according to the second indication information.

In a possible implementation manner of the second aspect, the PDCP layer of the second terminal device periodically reports the maintained PDCP COUNT of the first bearer to the RRC layer of the second terminal device according to the first period, and the second terminal device reports the PDCP COUNT of the first bearer to the RRC layer of the second terminal device periodically. The RRC layer identifies whether the PDCP COUNT is about to rollover. The duration of the first cycle may be configured by the RRC layer of the second terminal device to the PDCP layer of the second terminal device, or may be determined by the PDCP layer itself.

It should be noted that the PDCP layer or the RRC layer of the second terminal device may determine or identify that the PDCP COUNT is about to be overturned according to the first rule. For example, the first rule may be that the HFN in the PDCP COUNT value reaches the maximum value, or the HFN The highest bit becomes 1, or the PDCP COUNT value reaches the first threshold value, etc. This embodiment of the present application does not limit the first rule. It can be understood that the first rule may be determined by the second terminal device itself, may also be specified by a standard protocol, may be determined through negotiation between the first terminal device and the second terminal device, or may be determined by the network The device configuration is also not limited in this embodiment of the present application.

In a possible implementation manner of the second aspect, the second terminal device receives a second message from the first terminal device, the second message includes the bearer identifier of the first bearer and the first logical channel identifier, and the second message uses The second terminal device modifies the logical channel identifier of the first bearer to the first logical channel identifier based on the second message.

In a possible implementation manner of the second aspect, the second terminal device receives a third message from the first terminal device, where the third message is used to request key update; the second terminal device verifies the encryption based on the third message key to update.

Optionally, in the first aspect and the second aspect, the first message may be a PC5 RRC message or a PDCP control PDU, and the first indication information includes a bearer identifier or a logical channel identifier of the first bearer.

Optionally, in the first aspect and the second aspect, the first indication information includes a PDCP COUNT value of the first bearer or a high-order bit of the PDCP COUNT value.

Optionally, in the first aspect and the second aspect, the first indication information includes information for indicating which transmission direction the PDCP COUNT is about to flip.

Optionally, in the first aspect and the second aspect, the second indication information includes a bearer identifier or a logical channel identifier of the first bearer.

Optionally, in the first aspect and the second aspect, the second indication information includes the PDCP COUNT value of the first bearer or the high-order bit of the PDCP COUNT value.

Optionally, in the first aspect and the second aspect, the second indication information includes information used to indicate which transmission direction the PDCP COUNT is about to flip.

In a third aspect, a communication device is provided, the communication device having a function of implementing the behavior in the method of the first aspect above. The functions can be implemented by hardware, or by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above functions. The communication device may be a terminal device, or a device capable of supporting the terminal device to implement the functions in the method of the first aspect. For example, the communication device may be a chip system.

In a possible design, the communication apparatus includes: a processing unit, configured to determine that the PDCP COUNT of the first bearer is about to be reversed, wherein the first bearer is a side between the first terminal device and the second terminal device initiated by the establishment uplink bearer; a sending unit, configured to send a second message to the second terminal device, where the second message includes a bearer identifier of the first bearer and a first logical channel identifier, and the second message is used to send the logical channel identifier of the first bearer The channel identifier is modified to the first logical channel identifier, or, used to send a third message to the second terminal device, where the third message is used to request key update; optionally, a receiving unit, configured to receive data from the second terminal device The first message of the first message, wherein the first message includes first indication information, the first indication information indicates that the PDCP COUNT of the first bearer is about to be flipped, or, for receiving the second indication information reported by the PDCP layer of the first terminal device, Wherein, the second indication information indicates that the PDCP COUNT of the first bearer is about to be reversed. These modules can perform the corresponding functions in the method examples of the first aspect. For details, please refer to the detailed descriptions in the method examples, which will not be repeated here.

In a fourth aspect, a communication device is provided, the communication device having a function of implementing the behavior in the method of the second aspect above. This function can be implemented by hardware or by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above functions. The communication device may be a terminal device, or a device capable of supporting the terminal device to implement the functions in the method of the second aspect. For example, the communication device may be a chip system.

In a possible design, the communication apparatus includes: a receiving unit, configured to receive a second message from the first terminal device, where the second message includes a bearer identifier of the first bearer and a first logical channel identifier, and the second message is used for Modifying the logical channel identifier of the first bearer to a first logical channel identifier, where the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established; the processing unit is configured to, based on the second message Modify the logical channel identifier of the first bearer to the first logical channel identifier. These modules can perform the corresponding functions in the method examples of the second aspect. For details, please refer to the detailed descriptions in the method examples, which will not be repeated here.

In a fifth aspect, a communication device is provided, and the communication device may be a communication device implementing the method of any one of the above-mentioned first and second aspects, or a communication device configured to implement any of the above-mentioned first and second aspects. A chip in a communication device of the method of one aspect. The communication device includes a communication interface, a processor, and optionally, a memory. Wherein, the memory is used to store computer programs or instructions or data, and the processor is coupled with the memory and the communication interface, and when the processor reads the computer program or instructions or data, the communication device is made to perform the functions of the first terminal device or the first terminal device in various aspects. Two methods performed by a terminal device.

It should be understood that the communication interface may be a transceiver in the communication device, for example, implemented by an antenna, a feeder, a codec, etc. in the communication device, or, if the communication device is a chip provided in the terminal device, the communication interface may is the input/output interface of the chip, such as input/output pins, etc. The transceiver is used for the communication device to communicate with other devices.

In a sixth aspect, a chip system is provided, the chip system includes a processor for implementing the communication method of any one of the first aspect and the second aspect. In one possible design, the system-on-a-chip further includes a memory for storing program instructions and/or data. The chip system can be composed of chips, and can also include chips and other discrete devices.

In a seventh aspect, a communication system is provided, the system comprising a communication device implementing the method of the first aspect and a communication device implementing the method of the second aspect.

In an eighth aspect, a computer program product is provided, the computer program product includes instructions, when the instructions are executed, the methods performed by the first terminal device in the above aspects are executed, or the methods in the above aspects are executed by the first terminal device. The method performed by the two terminal devices is performed.

In a ninth aspect, a computer-readable storage medium is provided, and the computer-readable storage medium stores a computer program or instruction, and when the computer program or instruction is executed, the method executed by the first terminal device in the above aspects is implemented ; or implement the method performed by the second terminal device in the above aspects.

Description of drawings

FIG. 1 is a schematic structural diagram of a communication system to which an embodiment of the application is applied;

2 is a schematic diagram of a protocol stack of a sidelink provided by an embodiment of the present application;

FIG. 3 is a schematic diagram of security protection of a sidelink provided by an embodiment of the present application;

FIG. 4 is a flowchart of an example of a communication method provided by an embodiment of the present application;

5 is a flowchart of another example of a communication method provided by an embodiment of the present application;

6 is a flowchart of another example of a communication method provided by an embodiment of the present application;

7 is a flowchart of another example of a communication method provided by an embodiment of the present application;

8 is a flowchart of another example of a communication method provided by an embodiment of the present application;

FIG. 9 is a schematic structural diagram of a communication device provided by an embodiment of the present application;

FIG. 10 is another schematic structural diagram of a communication device provided by an embodiment of the present application;

FIG. 11 is another schematic structural diagram of a communication device provided by an embodiment of the present application.

Detailed ways

The terms "first", "second" and "third" in the description and claims of the present application and the drawings are used to distinguish different objects, rather than to limit a specific order. In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or illustrations. Any embodiments or designs described in the embodiments of the present application as "exemplary" or "such as" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present the related concepts in a specific manner.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work, all belong to the scope of protection of the present application.

The technical solutions of the embodiments of the present application can be applied to various communication systems, for example, a long term evolution (Long Term Evolution, LTE) system, a fifth generation (5th generation, 5G) system or a new radio (new radio, NR) system, vehicle To other devices (Vehicle to X, V2X), where V2X can include vehicle to network (Vehicle to Network, V2N), vehicle to vehicle (Vehicle to Vehicle, V2V), vehicle to infrastructure (Vehicle to Infrastructure, V2I), vehicle Vehicle to Pedestrian (V2P), Long Term Evolution-Vehicle (LTE-V), Internet of Vehicle (IoV), Machine Type Communication (MTC), Internet of Things (IoT), Long Term Evolution-Machine (LTE-M), Machine to Machine (M2M), Non-Terrestrial Network (NTN) systems Or other communication systems that evolve in the future.

FIG. 1 is a schematic diagram of a communication system 100 suitable for this embodiment of the present application. The communication system may include at least two terminal devices, such as the

terminal devices

102 , 103 , 104 , and 105 in the communication system 100 shown in FIG. 1 . The communication system may further include at least one network device, such as the network device 101 in the wireless communication system 100 shown in FIG. 1 . A sidelink (sidelink, SL) can be established between the at least two terminal devices, and a sidelink is a link established between the terminal devices that can communicate directly, such as

links

120, 121, SL in FIG. 122, 123, and 124, the terminal devices that have established sidelinks can communicate directly. Wherein, a terminal device can establish a side link with one or more terminal devices, and the terminal device can receive data sent by one or more terminal devices that have established a side link with the terminal device. The interface between two terminal devices is called PC5 interface. The terminal device in the communication system can also establish a wireless connection with the network device for data communication. As shown in FIG. 1 , the

terminal devices

102 and 103 respectively establish

wireless links

110 and 111 with the network device. The terminal device in the communication system may also not establish a wireless link with the network device, such as the terminal devices 104 and 105 shown in FIG. 1 , which is not limited in this application. It can be understood that the above-mentioned side link may also be referred to as a side link, a side link, a straight-through link, etc., which is not limited in this embodiment of the present application.

In this application, a terminal device is a device with wireless transceiver function, which can be a fixed device, a mobile device, a handheld device, a wearable device, a vehicle, a vehicle-mounted device, or a device built into the above-mentioned device (for example, a communication module or system-on-chip, etc.). The terminal device is used to connect people, objects, machines, etc., and can be widely used in various scenarios. Also sometimes referred to as user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiment of the present application may be a mobile phone (mobile phone), a tablet computer (pad), a computer with a wireless transceiver function, a virtual reality (virtual reality, VR) terminal device, an augmented reality (augmented reality, AR) terminal Equipment, wireless terminals in industrial control, wireless terminals in internet of things (IoT) systems, wireless terminals in self-driving, wireless terminals in remote medical , wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, cellular phone, cordless phone , Session Initiation Protocol (SIP) telephones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or connected to Other processing equipment of wireless modems, in-vehicle equipment, in-vehicle communication devices, in-vehicle communication processing chips, wearable devices, terminal equipment in 5G networks or terminal equipment in the future evolved public land mobile network (PLMN) Wait. It should be understood that the present application does not limit the specific form of the terminal device.

In order to facilitate the understanding of the embodiments of the present application, the related concepts involved in the embodiments of the present application are now described.

If a terminal device needs to communicate with another terminal device on a side link, first, the terminal device can establish a side link bearer with another terminal device, and the terminal device sends the wireless resources of the PC5 port to the opposite terminal device. Control (Radio Resource Control, RRC) message to establish sidelink bearer. Fig. 2 is a protocol stack related to sidelink communication of PC5 port, wherein Fig. 2-a is a control plane protocol stack for the RRC layer, and the RRC layer is used to manage the radio configuration parameters of the radio interface. In addition, there is a control plane protocol stack for the PC5 signaling protocol (PC5-Signalling, PC5-S) layer, see Figure 2-b, the PC5-S layer is responsible for functions such as security establishment and key update. After the sidelink bearer is established, the two terminal devices send data packets based on the established sidelink bearer. Figure 2-c shows the user plane protocol stack for user data transmission, in which the service data adaptation protocol (service The data adaptation protocol, SDAP) layer completes the mapping of quality of service (Quality of service, QoS) flows to bearers. In each protocol stack, the bottom protocol layer includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (media access control) layer. , MAC) layer and physical (Physical, PHY) layer. The PDCP layer performs functions such as data encryption, integrity protection and header compression; the RLC layer performs functions such as data packet size matching; the MAC layer performs functions such as data scheduling and mapping between logical channels and transmission channels; the PHY layer is responsible for data in Wireless air interface transmission.

In order to ensure the security of sidelink communication and avoid being eavesdropped or tampered with by attackers, the data packets transmitted by the sidelink need to be protected. FIG. 3 is a schematic diagram of security protection for data packets transmitted on the side link. The sender encrypts the data, and the receiver decrypts the data. Whether it is encryption or decryption, the input parameters are the same, including the key, the COUNT value of the Packet Data Convergence Protocol (PDCP) of the data packet, and the logical channel carried by the side link corresponding to the data packet. Identity (Logic Channel Identity, LCID), transmission direction, and length of the keystream. Wherein, the COUNT is usually 32 bits. In this application, for the convenience of description, the default COUNT is 32 bits, but it is not limited. Each transmitted data packet has a COUNT value, and each terminal device independently maintains the COUNT value in each transmission direction carried by each side link. In the same transmission direction carried by a side link, The COUNT value of the next packet is the COUNTN value of the previous packet plus 1.

It should be noted that COUNT is a unique name used to number data packets, and COUNT is divided into two parts: Hyper Frame Number (HFN) and PDCP sequence number. HFN is the high-order bit of COUNT, and the PDCP sequence number is the low-order bit of COUNT, and the two together are 32 bits. For example, if the length of the PDCP sequence number occupies 11 bits, the HFN occupies 21 bits. The PDCP sequence number is transmitted on the wireless interface, but the HFN is not transmitted on the wireless interface, but is maintained by the sender and the receiver. The advantage of this is that the transmission overhead is reduced. If two terminal devices transmit a large number of data packets through the side link, the problem of COUNT value inversion may occur, that is, the COUNT value overflows and starts from 0 again, and also HFN starts from 0 again. This results in that different data packets use the same security input parameters, which increases the risk of key compromise and reduces security from a security point of view.

In view of this, the technical solutions of the embodiments of the present application are provided. The technical solutions provided by the embodiments of the present application are described below with reference to the accompanying drawings.

An embodiment of the present application provides a communication method. Please refer to FIG. 4 , which is a flowchart of the method. The method may be performed by two communication devices, eg a first terminal device and a second terminal device. Wherein, the first terminal device and the second terminal device may be various types of terminal devices described above or communication devices capable of supporting the functions required by the terminal device to implement the method.

S410. The first terminal device determines that the PDCP COUNT of the first bearer is about to be rolled over.

A sidelink bearer is established between the first terminal device and the second terminal device for data transmission between the two terminal devices, which is referred to as a first bearer here. With the transmission of data between the two terminal devices, it may happen that the PDCP COUNT of the first bearer is about to be reversed. Since a bearer can be bidirectional, the first terminal device can act as the sender to encrypt the data packet and then send the data packet to the second terminal device, and can also act as the receiver to receive and decrypt the data packet sent by the second terminal device. The number of data packets transmitted in the two transmission directions may be inconsistent. The first terminal device maintains two PDCP COUNTs for the first bearer, one of which is the PDCP COUNT maintained by the sender, which is used to encrypt the sent data. The other is the PDCP COUNT maintained as the receiver to decrypt the received data. Correspondingly, the second terminal device also maintains two PDCP COUNTs. It should be noted that the PDCP COUNT of the first bearer mentioned here is about to be reversed, which may be that the PDCP COUNT of the first bearer maintained by the first terminal device as the sender is about to be reversed, or the first terminal device as the receiver. The maintained PDCP COUNT of the first bearer is about to roll over, or both of them are about to roll over. That is to say, if the PDCP COUNT of any transmission direction on the first bearer is about to roll over, it can be considered that the PDCP of the first bearer is about to roll over. COUNT is about to roll over.

FIG. 5 is a possible implementation manner in which the first terminal device determines that the PDCP COUNT of the first bearer is about to be flipped. In this implementation manner, the PDCP layer of the first terminal device recognizes that the PDCP COUNT of the first bearer is about to be reversed, and the PDCP layer of the first terminal device reports the second indication information to the RRC layer of the first terminal device. Correspondingly, the first The RRC layer of a terminal device receives the second indication information reported by the PDCP layer of the first terminal device. The second indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over. The second indication information may include a bearer identifier of the first bearer, or a logical channel identifier of the first bearer. Optionally, the second indication information may also include the PDCP COUNT value or the high-order bit of the COUNT value of the first bearer. Optionally, the second indication information may also include information for indicating which transmission direction the PDCP COUNT is about to roll over, for example, the PDCP COUNT maintained by the second terminal device as the receiver is about to roll over, or the second terminal device as the receiver is about to roll over. The PDCP COUNT maintained by the sender is about to rollover. The RRC layer of the first terminal device determines, based on the second indication information, that the PDCP COUNT of the first bearer is about to be rolled over.

In another possible implementation manner, the PDCP layer of the first terminal device may periodically report the maintained PDCP COUNT of the first bearer to the RRC layer of the first terminal device according to the first period, and the first terminal device The RRC layer identifies whether the PDCP COUNT is about to rollover. The duration of the first cycle may be configured by the RRC layer of the first terminal device to the PDCP layer of the first terminal device, or may be determined by the PDCP layer itself.

FIG. 6 is another possible implementation manner in which the first terminal device determines that the PDCP COUNT of the first bearer is about to be flipped. Specific steps are as follows:

S610. The second terminal device determines that the PDCP COUNT of the first bearer is about to be rolled over.

For the method for the second terminal device to determine that the PDCP COUNT of the first bearer is about to be inverted, refer to the method for the first terminal device to determine that the PDCP COUNT of the first bearer is about to be inverted in FIG. 5, and simply replace the first terminal device with the second terminal device That’s it, no further details are given here.

S620. The second terminal device determines that the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established by the first terminal device.

The sidelink bearer between two terminal devices may be initiated by the first terminal device or initiated by the second terminal device, and even if there are multiple sidelink bearers, some of which are initiated by the first terminal device. The terminal device initiates the establishment, and the other part is initiated by the second terminal device. The second terminal device determines whether the first bearer is a sidelink bearer initiated and established by the first terminal device. If the second terminal device determines that the first bearer is a sidelink bearer initiated and established by the first terminal device, it proceeds to step S630.

S630. The second terminal device sends the first message to the first terminal device.

Correspondingly, the first terminal device receives the first message. The first message includes first indication information, where the first indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over. The second terminal device sends the first message to the first terminal device to trigger the first terminal device to initiate a bearer modification procedure or a key update procedure for the first bearer, instead of directly initiating a bearer modification procedure or a key update procedure for the first bearer Update process, the advantage of this is that the PDCP COUNT carried by a side link is about to be reversed, and the terminal device that initiates the establishment of the side link bearer solves the problem of possible reduction in security, which can reduce the complexity. Reduce the impact on data transfer.

The first indication information may include a bearer identifier of the first bearer, or a logical channel identifier of the first bearer, and the bearer identifier may be a configuration index of a sidelink bearer of the PC5 interface. Optionally, the first indication information may also include the PDCP COUNT value of the first bearer or the high-order bit of the PDCP COUNT value. Optionally, the first indication information may also include information used to indicate which transmission direction the PDCP COUNT is about to roll over, for example, the PDCP COUNT maintained by the second terminal device as the receiver is about to roll over, or the second terminal device as the receiver is about to roll over. The PDCP COUNT maintained by the sender is about to rollover.

The first message may be an RRC message of the PC5 interface, or may be a PDCP control protocol data unit (Protocol Data Unit, PDU). If the first message is a PDCP control PDU, after receiving the first message, the PDCP layer of the first terminal device reports the first indication information to the RRC layer of the first terminal device.

S640. The first terminal device determines, based on the first indication information, that the PDCP COUNT of the first bearer is about to roll over.

For example, it may be that the RRC layer of the first terminal device determines, based on the first indication information, that the PDCP COUNT of the first bearer is about to be rolled over. Specifically, based on the bearer identification of the first bearer or the logical channel identification of the first bearer included in the first indication information, it is learned that the PDCP COUNT of the first bearer is about to be reversed.

S420. The first terminal device determines that the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established by the first terminal device.

This step is optional. For example, if the implementation shown in FIG. 6 is adopted in step S410, that is, the first terminal device determines that the PDCP COUNT of the first bearer is about to be reversed based on the first indication information received from the second terminal device, it can be By default, it is considered that the first bearer was established by the first terminal device, so this step can be skipped and step S430 is entered. Step S420 is performed.

The sidelink bearer between two terminal devices may be initiated by the first terminal device or initiated by the second terminal device, and even if there are multiple sidelink bearers, some of which are initiated by the first terminal device. The terminal device initiates the establishment, and the other part is initiated by the second terminal device. Whether the first bearer is a sidelink bearer initiated and established by the first terminal device may be determined by the RRC layer of the first terminal device. If it is determined that the first bearer is not a sidelink bearer initiated and established by the first terminal device, that is, the first bearer is a sidelink bearer initiated and established by the second terminal device, the first The terminal device sends a message to notify the opposite party that the PDCP COUNT of the first bearer is about to be flipped. Refer to Figure 6 and related descriptions. The difference is that the roles of the first terminal device and the second terminal device need to be interchanged. Here No longer. The PDCP COUNT carried by a sidelink is about to be reversed. The terminal device that initiates the establishment of the sidelink bearer can solve the problem of possible security reduction, which can reduce the complexity and reduce the impact on data transmission.

If the RRC layer of the first terminal device determines that the first bearer is a sidelink bearer initiated and established by the first terminal device, step S430 is entered.

It should be noted that the execution sequence of step S410 and step S420 can be interchanged, which is not limited here.

S430. The first terminal device initiates a bearer modification process or a key update process for the first bearer.

In order to solve the problem of reduced security, that is, to prevent different data packets from using the same security input parameters, in this embodiment of the present application, it may be implemented through a bearer modification or key update process. It should be noted that, the first terminal device may also initiate bearer modification and key update procedures at the same time to solve the problem of reduced security.

Method 1: Bearing Modification

FIG. 7 exemplarily describes a possible bearer modification process. As shown in FIG. 7 , a bearer modification process may be initiated by the RRC layer of the first terminal device to modify the logical channel identifier of the first bearer to another available logical channel identifier. The available logical channel identifiers refer to logical channel identifiers that have not been used together with the current key, which is the key being used for communication between the first terminal device and the second terminal device. Since the logical channel identifier is one of the security input parameters, the change of the logical channel identifier of the first bearer can avoid the problem of reduced security. The specific steps can be as follows:

S710. The first terminal device determines that there is an available logical channel identifier.

For example, a maximum of 32 logical channel identities can be supported between two terminal devices. Each time a sidelink bearer is added, an available logical channel identifier will be allocated. Then, among the 32 logical channel identifiers, the logical channel identifier that is not allocated and used in conjunction with the current key can be regarded as the available logical channel identifier. For example, when starting to use the current key, there are 3 sidelink bearers between the two terminal devices, and their logical channel IDs are 1, 2 and 3 respectively. When a new one needs to be added between the two terminal devices When the sidelink bearer A, the available logical channel identifiers are 4-32. If the logical channel identifier allocated to this sidelink bearer is 4, the logical channel identifier 4 becomes unavailable. When another sidelink bearer B needs to be added between the two terminal devices, the available logical channel identifiers at this time are 5-32. It can be understood that the maximum number of 32 logical channel identifiers is an example of a scenario, and the maximum number of logical channel identifiers that can be supported between two terminal devices may also be other numbers.

It should be noted that even if a certain sidelink bearer is released, the logical channel identifier allocated to this sidelink bearer is unavailable, otherwise there will be a problem that different data packets use the same security input parameters. There may therefore be a problem that there is no logical channel identity available. After the key is updated, this assigned logical channel identity becomes available again.

If the first terminal device determines that there is no available logical channel identifier, it can initiate a key update process to solve the problem of reduced security, and for details, refer to the related description of FIG. 8 below.

If the first terminal device determines that there is an available logical channel identifier, the first terminal device may select one of the available logical channel identifiers as the target logical channel identifier of the first bearer, which is referred to as the first logical channel identifier herein. The first terminal device may randomly select one of the available logical channel identifiers or select one as the first logical channel identifier according to preset conditions or rules, for example, select the smallest available logical channel identifier.

Optionally, S710 may be implemented by the RRC layer of the first terminal device. The RRC layer is responsible for radio resource configuration, and is implemented by the RRC layer, with low implementation complexity.

S720. The first terminal device sends a second message to the second terminal device, where the second message includes the bearer identifier of the first bearer and the first logical channel identifier, and is used to modify the logical channel identifier of the first bearer to the first logical channel identifier .

Correspondingly, the second terminal device receives the second message. The bearer identifier of the first bearer may be a configuration index of a sidelink bearer of the PC5 interface, which is used to indicate that the modification is for the first bearer. The first logical channel identifier is used to indicate the target logical channel identifier of the first bearer. Optionally, the second message may only be used to instruct to modify the logical channel identifier of the first bearer without modifying other parameters of the first bearer, that is, other configurations of the first bearer except the logical channel identifier continue to be used.

In a possible implementation manner, the second message may be an RRC reconfiguration message of the PC5 interface.

In this embodiment of the present application, a bearer modification method is adopted, that is, by modifying the logical channel identifier of the first bearer without deleting the first bearer and adding another bearer, it is possible to avoid the cause of discarding the cached data packets due to the deletion of the first bearer. Large transmission interruptions and packet loss problems. In addition, because in the sidelink scenario, the COUNT value carried by the sidelink is maintained by the two terminal devices that communicate with each other, the base station cannot perceive the COUNT value carried by the sidelink, so the base station does not know what When the process of deleting and creating a new bearer is initiated at the same time, the problem in the sidelink scenario cannot be solved, but this problem can be solved by the embodiments of the present application.

S730. The second terminal device modifies the logical channel identifier of the first bearer to the first logical channel identifier based on the second message.

After receiving the second message, the second terminal device finds that the bearer identifier of the first bearer included in the second message is the currently configured bearer identifier, and then learns that the second message initiates the bearer corresponding to the bearer identifier (that is The bearer modification process of the first bearer), so that the logical channel identification of the first bearer can be modified to the first logical channel identification according to the first logical channel identification contained in the second message.

Optionally, in the bearer modification process, the PDCP entity of the first bearer may not be re-established, and the PDCP COUNT of the first bearer maintained by the first terminal device and the second terminal device may continue to be used without being reset to 0. Even if the same PDCP COUNT value is used again after the PDCP COUNT is flipped, because the logical channel identifier of the first bearer has been modified, there will not be a problem that different data packets use the same security input parameters, so there is no problem The problem of reduced security. The advantage of continuing to use the maintained PDCP COUNT of the first bearer is that data transmission is less affected, and problems such as data packet loss will not occur. Optionally, if the PDCP COUNT value of the first bearer is X when the bearer is modified this time, before the next PDCP COUNT reaches the value X, but not before the rollover, the bearer modification process or the key update process can be performed again to avoid the occurrence of The problem of different packets using the same security input parameters.

Optionally, during the bearer modification process, the PDCP entity of the first bearer may also be re-established, and the PDCP COUNT of the first bearer maintained by the first terminal device and the second terminal device is reset to 0, that is, the first The terminal device and the second terminal device allocate PDCP COUNTs starting from 0 for subsequent data packets. By resetting the PDCP COUNT, the above-mentioned X value does not need to be saved, thus reducing the implementation complexity.

S740. The second terminal device sends a response message of the second message to the first terminal device, which is used to confirm that the modification of the logical channel identifier of the first bearer has been successfully completed.

Correspondingly, the first terminal device receives the response message of the second message. The response message of the second message may be an RRC reconfiguration complete message of the PC5 interface.

S750. The first terminal device modifies the logical channel identifier of the first bearer to the first logical channel identifier.

It should be noted that step S750 may occur after step S740, that is, after receiving the response message of the second message, or after step S720, that is, after sending the second message.

Method 2: Key update

In this manner, the key update process can be initiated by the first terminal device to change the key to a new key. Since the key is one of the security input parameters, even if the same PDCP COUNT value is used again, the change of the key will prevent the problem of different data packets using the same security input parameter, thus avoiding the security input that will occur. Sexual decline problem.

Figure 8 exemplarily describes a possible key update process.

S810. The RRC layer of the first terminal device reports the third indication information to the PC5-S layer of the first terminal device to request key update.

After the RRC layer of the first terminal device determines that the PDCP COUNT of the first bearer is about to be inverted, or, after determining that the PDCP COUNT of the first bearer is about to be inverted and there is no available logical channel identifier, the first terminal device's PC5 - The S layer reports third indication information, and the third indication information is used to trigger or request the PC5-S layer to initiate a key update process. Optionally, the third indication information includes a cause value, for example, the cause value indicates that the PDCP COUNT rollover occurs, or indicates that there is no available logical channel identifier, or indicates that the key needs to be updated.

S820. The PC5-S layer of the first terminal device initiates a key update process.

After receiving the third indication information, the PC5-S layer of the first terminal device determines and initiates a key update process with the second terminal device based on the third indication information. For example, the first terminal device sends a third message to the second terminal device for requesting key update, where the third message is a PC5-S layer message. The second terminal device receives the third message, and updates the key based on the third message. Optionally, the key update process of the PC5-S layer can refer to the prior art, for example, the first terminal device sends a direct link rekeying request (direct link rekeying request) message of the PC5-S layer to the second terminal device. , the message carries the parameters used for key update, which will not be repeated here.

It can be understood that, the above-mentioned manner 1 or manner 2 may specify which manner to be adopted by the protocol, or may be determined by the first terminal device to adopt manner 1 or manner 2.

For example, it may be determined by the RRC layer of the first terminal device whether to adopt the first mode or the second mode. In a possible implementation manner, when step S430 needs to be performed, or the first terminal device determines that the PDCP COUNT of the first bearer is about to be flipped and the first bearer is established between the first terminal device and the second terminal device After carrying the sidelink between the two, the RRC layer of the first terminal device determines whether there is an available logical channel identifier. If there is an available logical channel identifier, the bearer modification process shown in FIG. If there is no available logical channel identifier, the key update process shown in FIG. 8 (ie, mode 2) can be used. Since the key update process takes up more signaling overhead, and once the key is updated, the keys used by all the sidelink bearers between the first terminal device and the second terminal device are updated. For data transmission carried by other sidelinks between the first terminal device and the second terminal device, in this way, the bearer modification process can be preferentially used, thereby reducing signaling overhead and avoiding affecting other sidelink bearers data transmission. In another possible implementation manner, when step S430 needs to be performed, or the first terminal device determines that the PDCP COUNT of the first bearer is about to be flipped and the first bearer is initiated by the first terminal device and established with the second terminal device After the sidelink between them is carried, the first terminal device directly uses the key update process shown in FIG. 8 (ie, the second mode), thereby reducing the implementation complexity.

In this embodiment, after it is determined that the PDCP COUNT of the first bearer is about to be reversed and the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established, the first terminal device initiates the bearer The modification process modifies the logical channel identifier of the first bearer to another available logical channel identifier, or the RRC layer of the first terminal device reports the third indication information for requesting key update to the PC5-S layer of the first terminal device In order to trigger the PCS-5 layer to initiate the key update process, the problem of different data packets using the same security input parameters is solved, and the security reduction problem that will occur is avoided.

The apparatus for implementing the above method in the embodiments of the present application will be described below with reference to the accompanying drawings. Therefore, the above content can be used in subsequent embodiments, and repeated content will not be repeated.

FIG. 9 is a schematic block diagram of a communication apparatus 900 provided by an embodiment of the present application. The communication apparatus 900 may correspondingly implement the functions or steps implemented by the first terminal device or the second terminal device in each of the foregoing method embodiments.

In some possible implementations, the communication apparatus may include one or more of a sending unit 910 , a receiving unit 920 and a processing unit 930 . Optionally, a storage unit may also be included, and the storage unit may be used to store instructions (codes or programs) and/or data. The sending unit 910, the receiving unit 920 and the processing unit 930 may be coupled with the storage unit, for example, the processing unit 930 may read instructions (codes or programs) and/or data in the storage unit to implement corresponding methods. The above-mentioned units may be set independently, or may be partially or fully integrated.

In some possible implementation manners, the communication apparatus 900 can correspondingly implement the behaviors and functions of the first terminal device in the foregoing method embodiments. For example, the communication apparatus 900 may be a first terminal device, or may be a component (eg, a chip or a circuit) applied in the first terminal device. The sending unit 910 and the receiving unit 920 may be respectively configured to perform all sending or receiving operations performed by the first terminal device in the foregoing method embodiments, for example, S630 in the embodiment shown in FIG. 6 or the embodiment shown in FIG. 7 . S720 and S740 in, and/or other processes for supporting the techniques described herein. Wherein, the processing unit 930 is configured to perform all operations performed by the first terminal device in the foregoing method embodiments except for the transceiving operations, and/or to support other processes of the technology described herein.

In some embodiments, the processing unit 930 is configured to determine that the PDCP COUNT of the first bearer is about to be reversed, where the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established.

Optionally, the processing unit 930 is configured to identify at the PDCP layer that the PDCP COUNT of the first bearer is about to be overturned, and report second indication information to the RRC layer, where the second indication information indicates that the PDCP COUNT of the first bearer is about to be overturned. The layer determines that the PDCP COUNT of the first bearer is about to be rolled over based on the second indication information. When it is determined that the PDCP COUNT of the first bearer is about to be rolled over, the processing unit 930 may initiate a bearer modification process with the second terminal device for the first bearer, or initiate a key update process with the second terminal device.

Optionally, the processing unit 930 is further configured to determine whether there is an available logical channel identifier, where the available logical channel identifier is a logical channel identifier that has not been used with the current key. When the processing unit 930 determines that there is an available logical channel identifier, the processing unit 930 initiates a bearer modification process with the second terminal device for the first bearer; when the processing unit 930 determines that there is no available logical channel identifier, the processing unit 930 initiates a key update process with the second terminal device.

The sending unit 910 is configured to send a second message to the second terminal device, wherein the second message includes the bearer identifier of the first bearer and the first logical channel identifier, and the second message is used to modify the logical channel identifier of the first bearer to the first bearer identifier. A logical channel identifier, or used to send a third message to the second terminal device, where the third message is used to request key update.

As an optional implementation manner, the receiving unit 920 is configured to receive a first message from the second terminal device, where the first message includes first indication information, and the first indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over , or, for receiving the second indication information reported by the PDCP layer of the first terminal device, where the second indication information indicates that the PDCP COUNT of the first bearer is about to be reversed.

It should be understood that the processing unit 930 in this embodiment of the present application may be implemented by at least one processor or a processor-related circuit component, and the sending unit 910 and the receiving unit 920 may be implemented by a transceiver or a transceiver-related circuit component or a communication interface.

In some possible implementation manners, the communication apparatus 900 can correspondingly implement the behaviors and functions of the second terminal device in the foregoing method embodiments. For example, the communication apparatus 900 may be the second terminal device, or may be a component (such as a chip or a circuit) applied in the second terminal device. The sending unit 910 and the receiving unit 920 may be configured to perform all receiving or sending operations performed by the second terminal device in the above method embodiments, for example, S630 in the embodiment shown in FIG. 6 or the implementation shown in FIG. 7 . Examples S720 and S740, and/or other processes for supporting the techniques described herein. The processing unit 930 is configured to perform all the operations performed by the second terminal device in the foregoing method embodiments except for the transceiving operations, and/or to support other processes of the technology described herein.

The sending unit 910 is configured to send a first message to the first terminal device, where the first message includes first indication information, and the first indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over.

As an optional implementation manner, the receiving unit 920 is configured to receive second indication information reported by the PDCP layer of the second terminal device, where the second indication information indicates that the PDCP COUNT of the first bearer is about to be reversed, or is used to receive a second message from the first terminal device, where the second message includes the bearer identifier of the first bearer and the first logical channel identifier, and the second message is used to modify the logical channel identifier of the first bearer to the first logical channel identifier, or It is used to receive a third message from the first terminal device, and the third message is used to request key update.

It should be understood that the processing unit 930 in this embodiment of the present application may be implemented by a processor or a processor-related circuit component, and the sending unit 910 and the receiving unit 920 may be implemented by a transceiver or a transceiver-related circuit component.

The storage unit in the above embodiment may be implemented by a memory.

FIG. 10 shows a communication apparatus 1000 provided by an embodiment of the present application. The communication apparatus 1000 may be a terminal device, which can implement the function of the first terminal device or the second terminal device in the method provided by the embodiment of the present application; the communication apparatus 1000 is also It may be a device capable of supporting the first terminal device or the second terminal device to implement the corresponding functions in the methods provided in the embodiments of the present application. Wherein, the communication apparatus 1000 may be a chip system. In this embodiment of the present application, the chip system may be composed of chips, or may include chips and other discrete devices.

The communication apparatus 1000 includes at least one processor 1020, which is configured to implement or support the communication apparatus 1000 to implement the function of the first terminal device or the second terminal device in the methods provided in the embodiments of this application. For details, refer to the detailed description in the method example, which is not repeated here.

Communication apparatus 1000 may also include at least one memory 1030 for storing program instructions and/or data. Memory 1030 is coupled to processor 1020 . The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units or modules, which may be in electrical, mechanical or other forms, and is used for information exchange between devices, units or modules. The processor 1020 may cooperate with the memory 1030 . The processor 1020 may execute program instructions and/or data stored in the memory 1030 to cause the communication apparatus 1000 to implement the corresponding method. Optionally, at least one of the at least one memory may be included in the processor.

The communication apparatus 1000 may further include a communication interface 1010 for communicating with other devices through a transmission medium, so that the devices used in the communication apparatus 1000 may communicate with other devices. Exemplarily, when the communication device is the first terminal device, the other device is the second terminal device; or, when the communication device is the second terminal device, the other device is the first terminal device. The processor 1020 may utilize the communication interface 1010 to send and receive data. The communication interface 1010 may specifically be a transceiver. For example, the above-mentioned transmitting unit 910 and receiving unit 920 constitute the communication interface 1010 .

The specific connection medium between the communication interface 1010 , the processor 1020 , and the memory 1030 is not limited in this embodiment of the present application. Exemplarily, in the embodiment of the present application, the memory 1030, the processor 1020, and the communication interface 1010 are connected through a bus 1040 in FIG. 10, and the bus is represented by a thick line in FIG. A schematic illustration is provided, but not limited. The bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of presentation, only one thick line is used in FIG. 10, but it does not mean that there is only one bus or one type of bus.

In this embodiment of the present application, the processor 1020 may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, which can realize Alternatively, each method, step, and logic block diagram disclosed in the embodiments of the present application are executed. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of the methods disclosed in conjunction with the embodiments of the present application may be directly embodied as executed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

In this embodiment of the present application, the memory 1030 may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), etc., or a volatile memory (volatile memory), Such as random-access memory (random-access memory, RAM). Memory is, but is not limited to, any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory in this embodiment of the present application may also be a circuit or any other device capable of implementing a storage function, for storing program instructions and/or data.

It should be noted that, the communication device in the above embodiment may be a terminal device or a circuit, and may also be a chip applied in the terminal device or other combined devices or components having the functions of the above-mentioned terminal device. When the communication device is a terminal device, the transceiver unit may be a transceiver, which may include an antenna and a radio frequency circuit, etc., and the processing module may be a processor, such as a central processing unit (central processing unit, CPU). When the communication device is a component having the functions of the above terminal equipment, the transceiver unit may be a radio frequency unit, and the processing module may be a processor. When the communication device is a chip system, the transceiver unit may be an input and output interface of the chip system, and the processing module may be a processor of the chip system.

FIG. 11 shows a schematic structural diagram of a simplified terminal device. For the convenience of understanding and illustration, in FIG. 11 , the terminal device takes a mobile phone as an example. As shown in FIG. 11 , the terminal device includes a processor, a memory, a radio frequency circuit, an antenna, and an input and output device. The processor is mainly used to process the communication protocol and communication data, control each unit, execute the software program, process the data of the software program, and so on. The memory is mainly used to store software programs and data. The radio frequency circuit is mainly used for the conversion of the baseband signal and the radio frequency signal and the processing of the radio frequency signal. Antennas are mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, and keyboards, are mainly used to receive data input by users and output data to users. It should be noted that some types of equipment may not have input and output devices.

When data needs to be sent, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and sends the radio frequency signal through the antenna in the form of electromagnetic waves. When data is sent to the device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor, which converts the baseband signal into data and processes the data. For ease of illustration, only one memory and processor are shown in FIG. 11 . In an actual device product, there may be one or more processors and one or more memories. The memory may also be referred to as a storage medium or a storage device or the like. The memory may be set independently of the processor, or may be integrated with the processor, which is not limited in this embodiment of the present application.

In the embodiments of the present application, the antenna and the radio frequency circuit with a transceiver function may be regarded as the transceiver unit of the apparatus, and the processor with the processing function may be regarded as the processing unit of the apparatus. As shown in FIG. 11 , the apparatus includes a transceiver unit 1110 and a processing unit 1120 . The transceiver unit 1110 may also be referred to as a transceiver, a transceiver, a transceiver, or the like. The processing unit 1120 may also be referred to as a processor, a processing board, a processing module, a processing device, and the like. Optionally, the device for implementing the receiving function in the transceiver unit 1110 may be regarded as a receiving unit, and the device for implementing the transmitting function in the transceiver unit 1110 may be regarded as a transmitting unit, that is, the transceiver unit 1110 includes a receiving unit and a transmitting unit. The transceiver unit 1110 may also be sometimes referred to as a transceiver, a transceiver, or a transceiver circuit or the like. The receiving unit may also sometimes be referred to as a receiver, receiver, or receiving circuit, or the like. The transmitting unit may also sometimes be referred to as a transmitter, a transmitter, or a transmitting circuit, or the like.

It should be understood that the transceiving unit 1110 is configured to perform the sending and receiving operations of the terminal device in the above method embodiments, and the processing unit 1120 is configured to perform other operations on the terminal device in the above method embodiments except the transceiving operations.

For example, in one implementation, the transceiver unit 1110 may be used to perform S630 in the embodiment shown in FIG. 6, and/or to support other processes of the techniques described herein.

For another example, in one implementation, the transceiver unit 1110 may be configured to perform S720 and S740 in the embodiment shown in FIG. 7 , and/or other processes for supporting the techniques described herein.

When the communication device is a chip-type device or circuit, the device may include a transceiver unit and a processing unit. The transceiver unit may be an input/output circuit and/or a communication interface; the processing unit may be an integrated processor, a microprocessor or an integrated circuit.

An embodiment of the present application further provides a communication system. Specifically, the communication system may include a first terminal device and a second terminal device, or may further include more terminal devices. Exemplarily, the communication system includes a first terminal device and a second terminal device for implementing the relevant functions of the above-mentioned FIG. 4 , FIG. 5 and FIG. The first terminal device and the second terminal device with the relevant functions, or the communication system includes the first terminal device and the second terminal device for implementing the relevant functions of the above-mentioned FIG. 4 , FIG. 6 and FIG. 7 , or the communication system includes A first terminal device and a second terminal device for implementing the functions related to the embodiments of FIG. 4 , FIG. 6 , and FIG. 8 .

Embodiments of the present application also provide a computer-readable storage medium, including a computer program or instruction, which, when executed, for example, by a computer or a processor, enables the first terminal in any one of FIG. 4 to FIG. 8 The method performed by the device or the second terminal device is performed.

Embodiments of the present application also provide a computer program product, including instructions that, when executed, for example, by a computer or a processor, make the first terminal device or the second terminal in any one of FIGS. 4 to 8 . The method performed by the device is executed.

An embodiment of the present application provides a chip system, where the chip system includes a processor, and may also include a memory, for implementing the functions of the first terminal device or the second terminal device in the foregoing method. The chip system can be composed of chips, and can also include chips and other discrete devices.

It should be understood that the terms "system" and "network" in the embodiments of the present application may be used interchangeably. "At least one" means one or more, and "plurality" means two or more. "And/or", which describes the association relationship of the associated objects, indicates that there can be three kinds of relationships, for example, A and/or B, which can indicate: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A, B can be singular or plural. The character "/" generally indicates that the associated objects are an "or" relationship. "At least one item(s) below" or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (a) of a, b or c may represent: a, b, c, a-b, a-c, b-c or a-b-c, wherein a, b, c may be single or multiple.

And, unless stated to the contrary, the ordinal numbers such as “first” and “second” mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, sequence, priority or priority of multiple objects. Importance. For example, the first message and the second message are only for distinguishing different messages, but do not indicate the difference in priority, sending order, or importance of the two kinds of messages.

It should be understood that the processor mentioned in the embodiments of the present application may be a CPU, and may also be other general-purpose processors, digital signal processors (digital signal processors, DSPs), application specific integrated circuits (application specific integrated circuits, ASICs), off-the-shelf processors Field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

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

It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, the memory (storage module) is integrated in the processor.

It should be noted that the memory described herein is intended to include, but not be limited to, these and any other suitable types of memory.

It should be understood that, in various embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not be dealt with in the embodiments of the present application. implementation constitutes any limitation.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

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

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions described in accordance with the embodiments of the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server, or data center Transmission to another website site, computer, server, or data center is by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), and the like.

The above are only specific implementations of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes within the technical scope disclosed in the embodiments of the present application. Or alternatives, all should be covered within the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be based on the protection scope of the claims.

Claims

A sidelink communication method, characterized in that the method comprises:

The first terminal device determines that the packet data convergence protocol PDCP COUNT of the first bearer is about to be reversed, and the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established;

The first terminal device initiates a bearer modification process with the second terminal device for the first bearer, or the first terminal device initiates a key update process with the second terminal device .
The method according to claim 1, wherein determining, by the first terminal device, that the PDCP COUNT of the first bearer is about to be reversed, comprising:

The first terminal device receives a first message from the second terminal device, wherein the first message includes first indication information, and the first indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over ;

The first terminal device determines that the PDCP COUNT of the first bearer is about to roll over based on the first indication information; or,

The radio resource control RRC layer of the first terminal device receives second indication information reported by the PDCP layer of the first terminal device, where the second indication information indicates that the PDCP COUNT of the first bearer is about to be reversed;

The first terminal device determines, based on the second indication information, that the PDCP COUNT of the first bearer is about to be rolled over.
The method of claim 2, wherein:

The first message is a PC5 RRC message or a PDCP control protocol data unit, and the first indication information includes a bearer identifier of the first bearer or a logical channel identifier of the first bearer.
The method according to any one of claims 1 to 3, wherein the first terminal device initiating a bearer modification process for the first bearer with the second terminal device comprises:

The first terminal device sends a second message to the second terminal device, where the second message includes the bearer identifier of the first bearer and the first logical channel identifier, the modified logical channel of the first bearer The identifier is the first logical channel identifier.
The method according to any one of claims 1 to 4, wherein before the first terminal device initiates a bearer modification process with the second terminal device for the first bearer, the method further comprises:

The first terminal device determines that there is an available logical channel identifier, wherein the available logical channel identifier is a logical channel identifier that has not been used with the current key.
The method according to any one of claims 1 to 3, wherein the first terminal device initiates a key update process with the second terminal device, comprising:

The first terminal device sends a third message to the second terminal device, where the third message is used to request key update.
The method according to claim 6, wherein before the first terminal device sends the third message to the second terminal device, the method further comprises:

The RRC layer of the first terminal device reports third indication information to the PC5-S layer of the first terminal device, where the third indication information is used to request key update;

The PC5-S layer of the first terminal device determines to initiate a key update process with the second terminal device based on the third indication information.
The method of claim 7, wherein:

The third indication information includes a cause value, and the cause value indicates that the PDCP COUNT is reversed, or that there is no available logical channel identifier.
The method according to claim 1, 6, 7 or 8, wherein before the first terminal device initiates a key update process with the second terminal device, the method further comprises:

The first terminal device determines that there is no available logical channel identifier, where the available logical channel identifier is a logical channel identifier that has not been used with the current key.
A sidelink communication method, characterized in that the method comprises:

The second terminal device receives a second message from the first terminal device, where the second message includes a bearer identifier of the first bearer and a first logical channel identifier, and the second message is used to convert the logical channel of the first bearer The identifier is modified to the first logical channel identifier, and the first bearer is a sidelink bearer between the first terminal device and the second terminal device initiated and established;

The second terminal device modifies the logical channel identifier of the first bearer to the first logical channel identifier based on the second message.
The method according to claim 10, wherein before the second terminal device receives the second message from the first terminal device, the method further comprises:

The second terminal device determines that the PDCP COUNT of the first bearer is about to be flipped;

The second terminal device sends a first message to the first terminal device, where the first message includes first indication information, and the first indication information indicates that the PDCP COUNT of the first bearer is about to be rolled over.
The method according to claim 11, wherein determining, by the second terminal device, that the PDCP COUNT of the first bearer is about to be reversed, comprising:

The radio resource control RRC layer of the second terminal device receives the second indication information reported by the PDCP layer of the second terminal device, the second indication information indicates that the PDCP COUNT of the first bearer is about to be inverted, the The second terminal device determines, according to the second indication information, that the PDCP COUNT of the first bearer is about to be rolled over.
The method of claim 12, wherein:

The first message is a PC5 RRC message or a PDCP control protocol data unit, and the first indication information includes a bearer identifier of the first bearer or a logical channel identifier of the first bearer.
The method according to any one of claims 10 to 13, characterized in that, further comprising:

receiving, by the second terminal device, a third message from the first terminal device, where the third message is used to request key update;

The second terminal device updates the key based on the third message.
A communication device for performing the method of any one of claims 1 to 14.
A communication device, comprising at least one processor and a memory;

the memory for storing program codes;

The processor is configured to execute the program code, so that the communication device executes the method according to any one of claims 1-14.
A communication system, characterized in that, the communication system comprises a communication device implementing the communication method according to any one of claims 1-9 and/or a communication device implementing the communication method according to any one of claims 10-14.
A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program or instruction, and when executed, the computer program or instruction makes the computer program or instruction described in any one of claims 1 to 14. method is executed.
A computer program product, characterized in that the computer program product includes instructions that, when executed, cause the method according to any one of claims 1 to 14 to be implemented.