Communication method and apparatus

Abstract

A communication method and apparatus, capable of effectively reducing the risk of lower-layer data / signaling of a PDCP layer being spoofed and tampered with, and improving the security of data transmission. The method comprises: during an exchange of a data packet (a first data packet) at a layer below the PDCP layer between a first communication apparatus and a second communication apparatus, the first communication apparatus performs integrity protection and / or encryption on the first data packet on the basis of a first COUNT, and the second communication apparatus performs integrity verification and / or decryption on the first data packet on the basis of the first COUNT, thereby achieving secure protection for the data packet at the layer below the PDCP layer. The first COUNT is determined on the basis of first air interface time corresponding to the first data packet and a first HFN corresponding to the first air interface time.

Description

Communication method and apparatus

[0001] The present application claims priority to the Chinese patent application No. 202411274054.7, filed on September 11, 2024, and entitled "Communication method and apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the field of communication, in particular to a communication method and apparatus. BACKGROUND

[0003] In a mobile communication scenario, the interaction of service information between a terminal and a network device needs to rely on a radio access network protocol stack. For example, in a user plane data transmission process, the radio access network protocol stack involved can include a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a media access link control (MAC) layer, and a physical (PHY) layer, etc. In a control user plane data transmission process, the radio access network protocol stack involved can also include a non-access stratum (NAS) layer and a radio resource control (RRC) layer, etc.

[0004] In order to ensure the security of RRC layer signaling and user plane data, the current common method is to encrypt / decrypt and integrity protect / verify data packets at the PDCP layer according to a security algorithm. However, the lower layer data / signaling of the PDCP layer still has the risk of being imitated and tampered. SUMMARY

[0005] The present application provides a communication method and apparatus, which can effectively reduce the risk of imitating and tampering the lower layer data / signaling of the PDCP layer, and improve the security of data transmission.

[0006] In a first aspect, a communication method is provided, which can be performed by a second communication device, by a component (e.g., a processor, a circuit, a chip, or a chip system, etc.) applied to the second communication device, or by a logic node, a logic module, or software that can implement all or part of the functions of the second communication device. The method includes: receiving a first data packet from a first communication device, the first data packet being a data packet at a lower layer of a packet data convergence protocol (PDCP) layer; performing integrity verification on the first data packet according to a first COUNT, and / or performing decryption on the first data packet according to the first COUNT, the first COUNT being determined according to a first hyper frame number (HFN) and a first air interface time corresponding to the first data packet, and the first HFN being an HFN corresponding to the first air interface time.

[0007] Based on the scheme, the embodiments of the present application provide a communication method. In the process of interaction of a first communication device and a second communication device on a data packet (a first data packet) at a lower layer of a PDCP layer, the first communication device can perform integrity protection and / or encryption on the first data packet based on a first COUNT, and the second communication device can perform integrity verification and / or decryption on the first data packet based on the first COUNT, thereby achieving security protection of the data packet at the lower layer of the PDCP layer and reducing the risk of forgery and tampering of the data / signaling at the lower layer of the PDCP layer. The first COUNT is determined according to a first HFN and a first air interface time corresponding to the first data packet, and the first HFN is an HFN corresponding to the first air interface time. That is, the determination of the first COUNT mainly depends on the air interface time corresponding to the first data packet. Since the first communication device and the second communication device that perform air interface communication through a wireless protocol stack can keep the air interface time synchronized, the first air interface time can be determined based on the air interface time of the transmission of the first data packet or scheduling information of the first data packet in the case of interaction of the first data packet, without the need to carry indication information for determining the first COUNT in the first data packet. This is conducive to achieving security protection of the first data packet without increasing air interface overhead or with a small amount of air interface overhead.

[0008] In a second aspect, a communication method is provided. The method can be performed by a first communication device, or by a component (e.g., a processor, a circuit, a chip, or a chip system, etc.) applied to the first communication device, or by a logic node, a logic module, or software that can implement all or part of the functions of the first communication device. The method includes performing integrity protection on to-be-transmitted data according to a first COUNT, and / or performing encryption on the to-be-transmitted data according to the first COUNT to obtain a first data packet, the first data packet being a data packet at a lower layer of a packet data convergence protocol (PDCP) layer; and sending the first data packet to a second communication device. The first COUNT is determined according to a first hyper frame number (HFN) and a first air interface time corresponding to the first data packet, and the first HFN is an HFN corresponding to the first air interface time. The technical effects brought by the second aspect can refer to the technical effects brought by the first aspect, which will not be repeated here.

[0009] In combination with the first aspect, the communication method further includes receiving or sending first scheduling information, the first scheduling information being used for scheduling the first data packet, and the first scheduling information indicating the first air interface time. In combination with the second aspect, the communication method further includes sending or receiving the first scheduling information, the first scheduling information being used for scheduling the first data packet, and the first scheduling information indicating the first air interface time.

[0010] Based on the scheme, the first air interface time is indicated by the first scheduling information, so that the understanding of the first COUNT by the second communication device and the understanding of the first COUNT by the first communication device are consistent, and the first air interface time does not need to be carried in the first data packet, which facilitates the second communication device to implement decryption and / or integrity check on the first data packet, and is conducive to controlling the air interface resource overhead for transmitting the first data packet.

[0011] In combination with the first aspect, the communication method further includes receiving or sending first indication information, the first indication information indicating that a redundancy version (RV) corresponding to the first data packet is RV0. In combination with the second aspect, the communication method further includes sending or receiving the first indication information, the first indication information indicating that the RV corresponding to the first data packet is RV0.

[0012] Based on the scheme, in a case where the first indication information indicates that the RV corresponding to the first data packet is RV0, the first communication device and the second communication device take the air interface time indicated by the first scheduling information as the first air interface time, without the need to add additional signaling for indicating the first air interface time, which is conducive to reducing the signaling overhead in the scheduling process of the first data packet.

[0013] In combination with the first aspect, the communication method further includes: receiving a second data packet from the first communication device, the second data packet being a retransmission data packet of the first data packet; performing integrity verification on the second data packet according to the first COUNT, and / or decrypting the second data packet according to the first COUNT. Correspondingly, in combination with the second aspect, the communication method further includes: sending a second data packet to the second communication device, the second data packet being a retransmission data packet of the first data packet, the second data packet being a data packet that is integrity protected and / or encrypted according to the first COUNT.

[0014] Based on the scheme, in the process of interacting with the retransmission data packet (second data packet) of the first data packet, the first communication device and the second communication device directly take the first COUNT corresponding to the first data packet as the COUNT corresponding to the second data packet, thereby ensuring the consistency of the content between the retransmission data packet and the initial transmission data packet, and avoiding conflict with the current retransmission mechanism.

[0015] In combination with the first aspect, the communication method further includes: receiving or sending second scheduling information, the second scheduling information being used for scheduling the second data packet, the second scheduling information indicating a second air interface time; and receiving or sending second indication information, the second indication information indicating a first offset and / or a second offset, the first offset being an offset between the first air interface time and the second air interface time, the second offset being an offset between the first HFN and the second HFN, the second HFN being an HFN corresponding to the second air interface time. Correspondingly, in combination with the second aspect, the communication method further includes: sending or receiving second scheduling information, the second scheduling information being used for scheduling the second data packet, the second scheduling information indicating a second air interface time; and receiving or sending second indication information, the second indication information indicating a first offset and / or a second offset, the first offset being an offset between the first air interface time and the second air interface time, the second offset being an offset between the first HFN and the second HFN, the second HFN being an HFN corresponding to the second air interface time.

[0016] Based on the scheme, in the process of interacting with the second data packet, the first communication device and the second communication device can directly take the first air interface time as the air interface time corresponding to the second data packet and take the first hyperframe number as the hyperframe number for determining the COUNT corresponding to the second data packet according to the second air interface time indicated by the second scheduling information and the first offset and the second offset indicated by the second indication information. On the one hand, this is conducive to ensuring the consistency of the retransmission data packet and the initial transmission data packet, and will not interfere with the performance of the current retransmission mechanism. On the other hand, in the case of determining the COUNT corresponding to the second data packet based on the second scheduling information and the second indication information, the first communication device and the second communication device have the same understanding of the COUNT corresponding to the second data packet regardless of whether the second data packet is a retransmission data packet, so that the transmission of the second data packet is not limited by the current retransmission mechanism.

[0017] With reference to the first aspect, the communication method further includes: receiving a third data packet from the first communication device, the third data packet being a retransmission data packet of the first data packet; performing integrity verification on the third data packet according to a second COUNT, and / or performing decryption on the third data packet according to the second COUNT, the second COUNT being determined according to a third HFN and a third air interface time corresponding to the third data packet, the third HFN being an HFN corresponding to the third air interface time. Correspondingly, with reference to the second aspect, the communication method further includes: generating a third data packet according to a second COUNT, the third data packet being a retransmission data packet of the first data packet; and sending the third data packet to the second communication device, wherein the second COUNT is determined according to a third HFN and a third air interface time corresponding to the third data packet, the third HFN being an HFN corresponding to the third air interface time.

[0018] Based on the scheme, in the process of retransmitting the first data packet, the retransmission data packet (the third data packet) is equivalent to a new initial transmission data packet, the second COUNT is generated according to the air interface time corresponding to the third data packet (the third air interface time) and the third HFN corresponding to the third air interface time, to implement security protection on the third data packet, so that the second communication device does not need to perform security verification and / or decryption on the received third data packet according to the first COUNT in the case that the first COUNT cannot be acquired, and the reliability of data transmission is improved.

[0019] With reference to the first aspect, the communication method further includes: receiving third scheduling information, the third scheduling information being used for scheduling the third data packet, and the third scheduling information indicating that the third air interface time and the RV corresponding to the third data packet are RV0. Correspondingly, with reference to the second aspect, the communication method further includes: sending or receiving third scheduling information, the third scheduling information being used for scheduling the third data packet, and the third scheduling information indicating that the third air interface time and the RV corresponding to the third data packet are RV0.

[0020] Based on the scheme, the first communication device and the second communication device can accurately take the air interface time indicated by the third scheduling information as the third air interface time, so that the understanding of the second COUNT by the second communication device and the understanding of the second COUNT by the first communication device are consistent, and the third air interface time does not need to be carried in the first data packet, nor does it need to be set with additional indication information or signaling, which is beneficial to controlling the air interface resource overhead for transmitting the third data packet.

[0021] With reference to the first aspect and the second aspect, in a possible design, the air interface time includes at least one of the following: a frame number FN, a subframe number SFN, or a time slot number.

[0022] In combination with the first aspect, the communication method further includes: receiving or sending third indication information, the third indication information indicating an initial value of the superframe number; and in a case where a frame number FN in the air interface time rolls over, adding 1 to the superframe number. In combination with the second aspect, the communication method further includes: sending or receiving third indication information, the third indication information indicating an initial value of the superframe number; and in a case where a frame number FN in the air interface time rolls over, adding 1 to the superframe number.

[0023] Based on the scheme, the first communication device and the second communication device maintain the HFN according to the same initial HFN and the same rule, and in this case, the first communication device and the second communication device can directly determine the first HFN according to the first air interface time and the maintained HFN, and the first data packet does not need to carry the first HFN, which is beneficial to further reduce air interface resource overhead for transmitting the first data packet on the basis of ensuring consistent understanding of the first COUNT by the first communication device and the second communication device.

[0024] In combination with the first aspect and the second aspect, in a possible design, the communication method further includes: receiving a system information block MIB, the MIB including fourth indication information, the fourth indication information indicating a current FN; and determining the air interface time according to the current FN.

[0025] Based on the scheme, the first communication device or the second communication device can maintain the air interface time according to the MIB, which significantly reduces the probability of air interface time asynchronization of the first communication device and the second communication device, and improves the reliability of implementing data packet security protection according to the air interface time.

[0026] In a third aspect, a communication device is provided, configured to implement various methods. The communication device includes modules, units, or means corresponding to the methods, which can be implemented by hardware, software, or by executing corresponding software by hardware. The hardware or software includes one or more modules or units corresponding to the functions.

[0027] In some possible designs, the communication device can include a processing module and a transceiver module. The processing module can be configured to implement the processing functions in any of the aspects and any possible implementation manners thereof. The transceiver module can include a receiving module and a sending module, which are configured to implement the receiving function and the sending function in any of the aspects and any possible implementation manners thereof.

[0028] In some possible designs, the transceiver module can be composed of a transceiver circuit, a transceiver, a transceiver, or a communication interface.

[0029] In a fourth aspect, a communication apparatus is provided, which comprises: a processor and a memory; the memory is configured to store computer instructions, which, when executed by the processor, cause the communication apparatus to perform the method of any one of the first aspect.

[0030] In a fifth aspect, a communication apparatus is provided, which comprises: a processor and a communication interface; the communication interface is configured to communicate with modules outside the communication apparatus; the processor is configured to execute computer programs or instructions, so as to cause the communication apparatus to perform the method of any one of the first aspect.

[0031] In a sixth aspect, a communication apparatus is provided, which comprises: at least one processor; the processor is configured to execute computer programs or instructions stored in a memory, so as to cause the communication apparatus to perform the method of any one of the first aspect. The memory can be coupled with the processor, or can be independent of the processor.

[0032] In a seventh aspect, a communication apparatus (for example, the communication apparatus can be a chip or a chip system) is provided, which comprises a processor configured to implement the functions involved in any one of the first aspect and the second aspect.

[0033] In some possible designs, the communication apparatus comprises a memory configured to store necessary program instructions and data.

[0034] In some possible designs, when the apparatus is a chip system, the apparatus can be composed of a chip, or can comprise a chip and other discrete devices.

[0035] It can be understood that the communication apparatus provided by the third aspect to the seventh aspect can be the second communication apparatus in the first aspect, or can be modules or units (for example, a chip, or a chip system, or a circuit) corresponding to the second communication apparatus in executing the method / operation / step / action described in the first aspect, or can be modules or units capable of being matched with the second communication apparatus, or can also be logic nodes, logic modules or software capable of implementing all or part of the functions of the second communication apparatus; or the communication apparatus can be the first communication apparatus in the second aspect, or can be modules or units (for example, a chip, or a chip system, or a circuit) corresponding to the first communication apparatus in executing the method / operation / step / action described in the second aspect, or can be modules or units capable of being matched with the first communication apparatus, or can also be logic nodes, logic modules or software capable of implementing all or part of the functions of the first communication apparatus.

[0036] It can be understood that when the communication apparatus in any one of the third aspect to the seventh aspect is a chip, the sending action / function of the communication apparatus can be understood as outputting information, and the receiving action / function of the communication apparatus can be understood as inputting information.

[0037] In an eighth aspect, a computer-readable storage medium is provided, which stores a computer program or instructions, when executed on a communication device, causes the communication device to perform the method of any one of the first aspect and the second aspect.

[0038] In a ninth aspect, a computer program product is provided, which contains instructions, when executed on a communication device, causes the communication device to perform the method of any one of the first aspect and the second aspect.

[0039] In a tenth aspect, a communication system is provided, which includes a first communication device and a second communication device. The second communication device is configured to perform the method of the first aspect and any possible design thereof, and the first communication device is configured to perform the method of the second aspect and any possible design thereof.

[0040] The technical effects brought by any one of the third aspect to the tenth aspect can refer to the technical effects brought by different design manners of the first aspect and the second aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 is a schematic diagram of an architecture of a wireless protocol stack provided by the present application;

[0042] FIG. 2 is a schematic diagram of a flow of implementing a security protection function provided by the present application;

[0043] FIG. 3 is a schematic diagram of a structure of a PDCP COUNT provided by the present application;

[0044] FIG. 4 is a schematic diagram of a flow of HARQ provided by the present application;

[0045] FIG. 5 is a schematic diagram of an RV version provided by the present application;

[0046] FIG. 6 is a schematic diagram of a flow of a multi-process HARQ provided by the present application;

[0047] FIG. 7 is a schematic diagram of a flow of implementing security protection based on SN provided by the present application;

[0048] FIG. 8 is a schematic diagram of an architecture of a communication system provided by the present application;

[0049] FIG. 9 is a schematic diagram of an architecture of a wireless protocol stack on a base station side provided by the present application;

[0050] FIG. 10 is a schematic diagram of an architecture of a wireless protocol stack on a terminal side provided by the present application;

[0051] FIG. 11 is a schematic diagram of a chip structure provided by the present application;

[0052] FIG. 12 is a flow chart of a communication method according to an embodiment of the present application;

[0053] FIG. 13 is a schematic diagram of COUNT according to an embodiment of the present application;

[0054] FIG. 14 is a schematic diagram of data retransmission according to an embodiment of the present application;

[0055] FIG. 15 is a schematic diagram of DCI and data packet according to an embodiment of the present application;

[0056] FIG. 16 is a schematic diagram of data retransmission according to another embodiment of the present application;

[0057] FIG. 17 is a schematic diagram of air interface time and HFN maintenance according to an embodiment of the present application;

[0058] FIGS. 18-20 are schematic diagrams of communication apparatuses according to embodiments of the present application. DETAILED DESCRIPTION

[0059] In the description of the present application, unless otherwise specified, " / " represents that the objects before and after the " / " are in an "or" relationship, for example, A / B can represent A or B; "and / or" in the present application is only a description of the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: A alone, A and B together, B alone, and the three cases, where A and B can be singular or plural.

[0060] In the description of the present application, unless otherwise specified, "multiple" means two or more than two. "At least one of the following" or the like means any combination of the items, including any combination of single item or multiple items. For example, at least one of a, b, or c can represent: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0061] In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, "first", "second" and the like are used to distinguish the same or similar items with basically the same function and role. The skilled in the art can understand that "first", "second" and the like do not limit the quantity and execution order, and "first", "second" and the like do not necessarily mean different.

[0062] In the present embodiments, the word "exemplary" or "for example" is used to mean "an example of" rather than "an example that is preferred" or "an example that is the best". Thus, use of any such terms is not intended to connote that the embodiments described herein (including any implicit combination of the embodiments) are the only way in which the recited or suggested features or technical, conceptual, or aesthetic characteristics can be implemented or utilized. Moreover, depending on the express context, the term "example" can or can not imply that the example is a preferred or desirable embodiment.

[0063] It can be understood that, the "embodiments" mentioned in the specification throughout mean that the specific features, structures or characteristics related to the embodiments are included in at least one embodiment of the present application. Therefore, the various embodiments throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It can be understood that, in various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0064] It can be understood that, in the present application, "when" and "if" refer to the corresponding processing under certain objective conditions, not the time limit, and do not require judgment action when implementing, nor does it mean that there are other limitations.

[0065] It can be understood that, in some scenarios, some optional features in the embodiments of the present application can be implemented independently without relying on other features, such as the scheme currently based on, to solve the corresponding technical problems and achieve the corresponding effects. In some scenarios, it can also be combined with other features according to demand. Correspondingly, the device given in the embodiments of the present application can also realize these features or functions, which will not be described here.

[0066] In the present application, the same or similar parts between various embodiments can be mutually referred to, unless otherwise specified. In various embodiments of the present application, the terms and / or descriptions between different embodiments are consistent and can be mutually referred to, unless otherwise specified and logically conflicted. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship. The following description of the embodiments of the present application does not constitute a limitation on the protection scope of the present application.

[0067] In order to facilitate the understanding of the technical scheme of the embodiments of the present application, first, a brief introduction of the related technology of the present application is given as follows.

[0068] 1. Radio access network side protocol stack:

[0069] The radio protocol stack at the radio access network side can be divided into a user plane protocol stack and a control plane protocol stack. Referring to (a) in FIG. 1, the user plane protocol stack between the terminal and the access network device mainly includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a media access control (MAC) layer, and a physical (PHY) layer, etc. Referring to (b) in FIG. 1, the control plane protocol stack mainly includes a non-access (NAS) layer, a radio resource control (RRC) layer, a PDCP layer, an RLC layer, a MAC layer, and a PHY layer, and the NAS layer is used for interaction between the terminal and the device in the core network.

[0070] Among them, the PHY layer belongs to the first layer (also referred to as layer 1 (L1)); the MAC layer, the RLC layer, the PDCP layer, and the SDAP layer belong to the second layer (also referred to as layer 2 (L2)); and the RRC layer and the NAS layer belong to the third layer (also referred to as layer 3 (L3)).

[0071] Currently, the PDCP layer is mainly used to process the RRC layer message on the control plane and the internet protocol (IP) data packet on the user plane. The main functions of the PDCP layer include: security functions (such as data encryption / decryption, data integrity protection / verification), compression / decompression of IP headers, discarding of timeout user plane data packets, user plane data reordering, and user plane data retransmission, etc.

[0072] Referring to (a) of FIG. 2, in a process in which the PDCP layer implements data encryption / decryption, the PDCP layer of a sender of a data packet identifies a data transmission direction, a data bearer, a key, a key stream length, and a PDCP data packet COUNT as inputs of a security algorithm, calculates a keystream block for encrypting / decrypting the data packet through the security algorithm, and then encrypts a plaintext block corresponding to the data packet according to the keystream block, generates a ciphertext block corresponding to the plaintext block, and transmits the ciphertext block to a receiver. The receiver, upon receipt of the ciphertext block, obtains the keystream block through the security algorithm in a similar manner, decrypts the ciphertext block according to the keystream block, and obtains the plaintext block.

[0073] Referring to (b) of FIG. 2, in a process in which the PDCP layer implements data integrity protection / verification, the PDCP layer of a sender of a data packet identifies a data transmission direction, a data bearer, a key, a message, and a PDCP data packet COUNT as inputs of a security algorithm, calculates a message authentication code (mac) corresponding to the data packet through the security algorithm, and transmits the message authentication code (denoted as mac1) to a receiver of the data packet. The PDCP layer of the receiver of the data packet calculates a message authentication code corresponding to the received data packet through the security algorithm, and determines that the data passes integrity verification in a case where the calculated message authentication code (denoted as mac2) is identical to the received message authentication code (mac1).

[0074] The key can be determined through RRC signaling negotiation, the data bearer is used to indicate a type of a channel to which the data packet is applied, such as a data radio bearer (DRB) and a signaling radio bearer (SRB), and the data transmission direction is used to indicate whether data transmission is uplink transmission or downlink transmission.

[0075] Referring to (a) in FIG. 3, COUNT input to a security algorithm in a PDCP layer is composed of a high bit hyper frame number (HFN) and a low bit PDCP sequence number (SN). The COUNT value is a 32-bit unsigned number, the PDCP SN is added to a data unit transmitted from the PDCP layer to a PLC layer, and the HFN is maintained by a transmitting end and a receiving end. In a case where the PDCP SN exceeds a maximum value of the PDCP SN, the HFN is incremented by 1 and indicates a PDCP SN rollover. Referring to (b) in FIG. 3, the PDCP SN can have a length of 12 bits or 18 bits, which can be determined by an upper protocol layer. The PDCP SN is used to indicate a sequence number of a data unit in a radio bearer.

[0076] 2. Hybrid automatic repeat request (HARQ):

[0077] HARQ is a transmission technology combining a forward error correction (FEC) code and an automatic repeat-request (ARQ) together. The key point thereof is that a receiving end stores received data, and performs soft combining of retransmitted data and the stored data upon a request for retransmission, thereby obtaining a certain combining gain.

[0078] In a process of data transmission using the HARQ technology, upon reception of data, the receiving end first checks the received data using the FEC, and performs automatic error correction of the received data within a range of an FEC capability. In a case where a degree of error of the received data exceeds a limit that can be handled by the FEC, the transmitting end is requested to retransmit the data using the ARQ mechanism, and a content of the retransmitted data is limited, thereby reducing an amount of data transmitted from the transmitting end as much as possible on the basis of successful decoding of the received data by the receiving end, and improving network transmission efficiency.

[0079] HARQ can be classified into synchronous HARQ and asynchronous HARQ according to a time at which retransmission occurs. In the synchronous HARQ, retransmission occurs at a fixed time, and the receiving end knows the time at which retransmission occurs in advance. In the asynchronous HARQ, retransmission can occur at any time, and the receiving end does not know the time at which retransmission occurs in advance.

[0080] According to the resources used in the retransmission process and the MAC order, the HARQ can be divided into adaptive HARQ and non-adaptive HARQ. The adaptive HARQ uses the MAC order and the radio bearer resource of the service channel in the retransmission process, which is different from the MAC order and the radio bearer resource of the service channel in the initial transmission process. The non-adaptive HARQ uses the MAC order and the radio bearer resource of the service channel in the retransmission process, which is consistent with the MAC order and the radio bearer resource of the service channel in the initial transmission process.

[0081] At present, the commonly used HARQ is asynchronous adaptive HARQ. Referring to (a) in FIG. 4, in the case of applying asynchronous adaptive HARQ in the downlink data transmission process, the base station needs to indicate the time domain position of the terminal for feeding back the data reception result, that is, the time domain position of the terminal for feeding back ACK (acknowledgment) and NACK (negative acknowledgment). The base station can send downlink control information (DCI) to the terminal through a physical downlink control channel (PDCCH), and the terminal obtains the DCI from the base station through PDCCH blind detection, and performs downlink data reception and data reception result feedback at the specified time domain position according to the indication of the DCI. In the case of needing to perform downlink data retransmission, the base station reindicates the time domain position of the data transmission and the time domain position of the feedback data reception for the terminal through the DCI.

[0082] In the downlink data transmission process, the DCI can include a downlink scheduling delay field (K0) and a downlink HARQ feedback delay field (K1). K0 is used to indicate the resource position (DL grant) of the terminal receiving downlink data on the physical downlink shared channel (PDSCH), and the time interval D1 between the resource position of the terminal receiving the DCI; K1 is used to indicate the resource position of the terminal feeding back ACK / NACK through the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH), and the time interval D2 between the resource position of the terminal receiving the DCI.

[0083] Similarly, referring to (b) in FIG. 4, in the case of applying asynchronous adaptive HARQ in the uplink data transmission process, the base station can send DCI to the terminal through PDCCH, and the terminal obtains the DCI from the base station through PDCCH blind detection. In the uplink data transmission process, the DCI can include an uplink scheduling delay field (K2), K2 is used to indicate the time domain position of the terminal sending uplink data to the base station through PUSCH (UL grant), and the interval D3 between the time domain position of the terminal receiving the DCI. In the case where uplink data retransmission is required, the base station re-schedules the time domain position of the terminal transmitting uplink data through DCI after unsuccessfully receiving the uplink data.

[0084] It should be understood that the uplink data and the downlink data are defined according to the flow direction of the data transmission, and the uplink data can be understood as the data flowing from the terminal to the base station, and the downlink data can be understood as the data flowing from the base station to the terminal.

[0085] 3. Redundancy version (RV):

[0086] RV is used to implement incremental redundancy (IR) HARQ transmission. According to whether the retransmitted bit information is the same as the initial transmitted bit information, HARQ includes IR-HARQ and chase combining (CC) HARQ.

[0087] In the CC-HARQ mode, the sending end transmits the same data in the initial transmission and retransmission process, the receiving end does not discard the received data, and combines the received data in the initial transmission and retransmission to decode and check, thereby obtaining a combining gain. In the IR-HARQ mode, the sending end transmits different redundancy bits in each transmission in the initial transmission and retransmission process, and the redundancy bits are used to implement cyclic redundancy check (CRC) on the data. The receiving end combines the redundancy bits obtained in each transmission process, and decodes and checks the retransmitted data according to the combined redundancy bits to obtain a combining gain. Compared with CC-HARQ, IR-HARQ can obtain a combining gain, and also obtain additional information quantity due to the existence of part of the redundancy bits, thereby improving the decoding performance.

[0088] In the IR-HARQ mode, before the data transmission occurs, the sending end encodes the original information element bits through the FEC algorithm to obtain encoded information element bits and a plurality of redundancy bits, and then forms a redundancy bit group corresponding to each RV through rate matching or puncturing.

[0089] For example, referring to (a) in FIG. 5, after the original information bits are encoded by a quasi-cyclic low-density parity-check (QC-LDPC) code, the redundancy bits (system bits S and check bits P) obtained after encoding are placed in a circular buffer, and the starting point of the redundancy bits corresponding to each RV is determined by rate matching based on the case that the redundancy bit group corresponding to each RV is determined based on rate matching and the circular buffer. During transmission based on RV, for each HARQ transmission, the data is read out from the circular buffer according to the RV number order.

[0090] For example, the starting points of the redundancy bits corresponding to different RVs are determined by a limited buffer rate matching method. In the case that the length of the original information bit 1 (denoted as BG1) after encoding is 66Z (Z is a lifting value), the starting points of RV0, RV1, RV2, and RV3 are 0, 17Z, 33Z, and 56Z, respectively. In the case that the length of the original information bit 2 (BG2) after encoding is 50Z, the starting points of RV0, RV1, RV2, and RV3 are 0, 13Z, 25Z, and 43Z, respectively. It can be found that the intervals between the starting points of adjacent RVs are different, that is, the interval between the first redundancy bits corresponding to each RV number is a non-uniform interval, which is beneficial to improve the decoding performance.

[0091] The redundancy bits contained in RV0 to RV3 can refer to (b) in FIG. 5. It can be found that RV0 and RV3 have a self-decoding function. In the QC-LDPC code design process, the first transmission performance is mainly used as a benchmark for design, so the initial transmission data is preferably transmitted by using RV0. When it is not determined whether the initial transmission data is received at the receiving end, the first retransmission data is preferably transmitted by using RV3 (because RV3 not only has a self-decoding capability but also has a certain incremental redundancy encoding performance gain), otherwise, the RV2 with the best incremental redundancy encoding performance is preferably used. The RV actually used in the data retransmission process is indicated by the RV number in the DCI. The RV number carried in the DCI is usually sequentially issued according to the order of 2, 3, and 1 according to the retransmission number.

[0092] In addition, in the process of applying the HARQ, the HARQ-related field in the DCI also includes a new data indicator (NDI) identifier. The NDI identifier is identified by 1 bit, having two states of 0 and 1. When the NDI identifier in the current DCI is different from the NDI identifier in the last received DCI, the terminal determines that the current DCI schedules the transmission of an initial data packet. When the NDI identifier in the current DCI is the same as the NDI identifier in the last received DCI, the terminal determines that the current DCI schedules the transmission of a retransmission data packet.

[0093] 4. Multi-process HARQ

[0094] In order to improve the data transmission efficiency in the process of applying the HARQ technology, a multi-process HARQ of the PHY layer is designed. Referring to (a) in FIG. 6, a base station transmits downlink data to a terminal by using a 4-process HARQ as an example.

[0095] The HARQ feedback timing is (n+4), and n is the air interface time of the current HARQ process for transmitting a downlink data packet. That is, after the base station transmits a data packet by using the HARQ Process 1 in the time slot 0, if the data packet transmitted in the time slot 0 is successfully received by the terminal (the base station receives an ACK from the terminal), the base station transmits the next data packet by using the HARQ Process 1 in the time slot 4. If the data packet transmitted in the time slot 4 is not successfully received by the terminal (the base station receives a NACK from the terminal), the base station performs the first retransmission of the data packet by using the HARQ Process 1 in the time slot 8. If the data packet transmitted in the time slot 8 is still not successfully received by the terminal, the base station performs the second retransmission of the data packet by using the HARQ Process 1 in the time slot 12, and continues to retransmit the data packet or transmit a new data packet in the time slot 16 according to the response information from the terminal.

[0096] Similarly, before the base station transmits a data packet in the time slot 4 by using the HARQ Process 1, the base station transmits other data packets in the time slot 1, the time slot 2 and the time slot 3 by using the HARQ Process 2, the HARQ Process 3 and the HARQ Process 4, respectively. The data packet transmission logic in each HARQ process can refer to the HARQ Process 1.

[0097] That is, in the process of data transmission by using multi-process HARQ, different time slots correspond to different HARQ processes, and the data transmission of each time slot corresponding to a HARQ process follows the retransmission logic, that is, a HARQ process sequentially transmits the data packets processed by the process. The data transmission between different HARQ processes is independent of each other, and the progress of data transmission of each HARQ process does not affect each other.

[0098] That is, at present, in the process of data transmission based on the wireless protocol stack, the PDCP layer implements security protection on the transmitted upper layer data packets. The principle of security protection is that the PDCP layer determines the COUNT corresponding to the data packet according to the PDCP SN in the data packet and the HFN maintained by the PDCP layer, and performs integrity check / protection and encryption / decryption on the data packet based on the COUNT corresponding to the data packet through the security algorithm. The current security protection algorithm cannot implement security protection on the data packets of the PDCP layer and the lower layer of the PDCP layer, such as the RLC layer, the MAC layer and the PHY layer.

[0099] Previously, the research report of the relevant institution has proposed that in the case of denial of service attack (DOS attack) by impersonating uplink scheduling request (scheduling request, SR) or buffer status report (buffer status report, BSR), the PHY layer and the MAC layer are prone to data packet tampering or impersonation problems, and carrier aggregation may cause user information leakage problem of the MAC layer. The Global System for Mobile Communications Association (GSMA) has proposed security protection suggestions for the data packets of the MAC layer, DCI, uplink control information (uplink control information, UCI) and other data packets of the lower layer of the PDCP layer. Referring to (b) in FIG. 6, it is suggested that the protected layer of security protection is extended from the upper layer of the PDCP layer to all protocol layers included in the wireless protocol stack.

[0100] In order to implement security protection on the data packets of the wireless protocol stack, as a possible implementation, the security function of the PDCP layer can be sunk to between the MAC layer and the PHY layer.

[0101] Referring to (a) in FIG. 7, taking the application of 3-process HARQ in the PHY layer and the SN as the sequence number of the upper layer data packet as an example. In the process of transmission of the upper layer data packet in the PHY layer, the sending end will transmit each upper layer data packet to the receiving end through different HARQ processes according to the SN corresponding to the upper layer data packet, and each HARQ process transmits data at different air interface times.

[0102] In the first transmission process, HARQ process 0 successfully completes the transmission of the data packet with SN=0, HARQ process 1 does not successfully complete the transmission of the data packet with SN=1, and HARQ process 2 successfully completes the transmission of the data packet with SN=2. In the second transmission process, HARQ process 0 and HARQ process 2 transmit new data packets, and HARQ process 1 retransmits the data packet corresponding to SN1. In the second transmission process, HARQ process 0 successfully completes the transmission of the data packet with SN=3, HARQ process 1 successfully completes the transmission of the data packet with SN=1, and HARQ process 2 successfully completes the transmission of the data packet with SN=4.

[0103] After two rounds of multi-process HARQ transmission, the receiving end successfully receives a total of 5 data packets. After sorting the data packets according to the air interface time of the received data packets, the SNs corresponding to the data packets are 0, 2, 3, 1, and 4, respectively. That is, the SNs corresponding to the data packets received by the receiving end can not be continuous with the air interface time. Therefore, directly sinking the security protection function of the PDCP layer to between the PHY layer and the MAC layer, in order to ensure that the receiving end can correctly calculate the COUNT corresponding to the data packet, the SN corresponding to the data packet needs to be added to the data packet.

[0104] For example, in the case of adding SN to each channel in the PHY layer, the main channels of the PHY layer are PDCCH, PDSCH, and PUSCH. In the case of implementing security protection in the physical layer, the data processing flow of the PDCCH channel transmitting DCI and the PDSCH channel and the PUSCH channel transmitting data packets can refer to (b) in FIG. 7. In the case of implementing security protection in the PDCCH channel, the base station first performs integrity protection on the DCI, then generates data after security protection in the physical layer through channel coding, modulation, and framing, and then sends the DCI to the terminal through air interface transmission. The terminal obtains the DCI through air interface reception, and performs integrity check on the DCI after de-framing, demodulation, and channel decoding. In the case of implementing security protection in the PDSCH channel and the PUSCH channel, the sending end encrypts and / or integrity protects the information element data, selects a redundancy version code according to the number of transmissions of the information element data, modulates and frames the encrypted and / or integrity protected information element data according to the selected redundancy version code, generates security protected data, and sends the security protected data to the terminal through air interface transmission. The terminal obtains the data through air interface reception, and performs de-framing, demodulation, and channel decoding on the data. In the decoding process, if the data is retransmitted data, the data is soft combined and then decoded, and after successful decoding, the decoded information element data is decrypted and / or integrity checked.

[0105] Since each channel needs to be independently operated in a secure manner, the SN needs to be added independently for each channel. After adding the SN for each channel, the format of the COUNT corresponding to each channel can refer to (c) in FIG. 7. The COUNT of the PDCCH channel is determined according to the PDCCH SN and the HFN. The COUNT of the PDSCH channel is determined according to the PDSCH SN and the HFN. The COUNT of the PUSCH channel is determined according to the PUSCH SN and the HFN. In this way, 12 bits to 18 bits of the SN field need to be added in each message of the channel, which greatly affects the air interface performance of the three channels of PDCCH, PDSCH and PUSCH.

[0106] Based on this, the embodiment of the present application provides a communication method, and a process of interacting a data packet (a first data packet) of a lower layer of a PDCP layer between a first communication device and a second communication device. The first communication device can perform integrity protection and / or encryption on the first data packet based on a first COUNT. The second communication device performs integrity check and / or decryption on the first data packet based on the first COUNT, thereby achieving security protection of the data packet of the lower layer of the PDCP layer, and reducing the risk of the data / signaling of the lower layer of the PDCP layer being imitated and tampered. The first COUNT is determined according to a first HFN and a first air interface time corresponding to the first data packet. The first HFN is an HFN corresponding to the first air interface time. That is, the determination of the first COUNT mainly depends on the air interface time corresponding to the first data packet. Since the first communication device and the second communication device performing air interface communication through a wireless protocol stack keep the air interface time synchronized, the first air interface time can be determined based on the air interface time of transmitting the first data packet or scheduling information of scheduling the first data packet in the case of interacting the first data packet. Therefore, it is not necessary to carry indication information for determining the first COUNT in the first data packet, which is beneficial to achieving security protection of the first data packet without increasing air interface overhead or with a small amount of air interface overhead.

[0107] The technical solutions of the embodiments of the present application can be applied to various communication systems, which can be a third generation partnership project (3GPP) communication system, for example, a long term evolution (LTE) system, a 4th generation (4G) system such as a new radio (NR) system, a 5G system, a system of mixed networking of LTE and 5G, a non-terrestrial network (NTN), a device-to-device (D2D) communication system, a vehicle to everything (V2X) communication system, a machine-type communication (MTC) system, an internet of things (IOT) system, or other future communication systems. The communication system can also be a non-3GPP communication system, which is not limited.

[0108] It should be noted that the above-mentioned communication system to which the present application is applicable is only an example, and the communication system to which the present application is applicable is not limited thereto. The communication system provided by the present application does not cause any limitation to the solutions of the present application. Herein, it is uniformly stated that the following will not be repeated.

[0109] Figure 8(a) shows a possible, non-limiting system diagram. As shown in Figure 8(a), the communication system includes a first communication device 801 and a second communication device 802, one of which is an access network device and the other is a terminal. The access network device can be a network-side device with wireless transceiving function, used to provide access service for the terminal, and the terminal can be a user-side device with wireless transceiving function.

[0110] Referring to Figure 8(b), the SDAP layer in the user plane protocol stack is located above the PDCP layer, the PDCP layer is located above the RLC layer, the RLC layer is located above the MAC layer, and the MAC layer is located above the physical layer. In the process of user plane data interaction between the terminal and the access network device, after the data reaches the sending end, each protocol layer processes the data packet in the order from top to bottom as shown in Figure 8(b) in turn, and finally transmits it to the receiving end through the air interface. The receiving end receives the data packet through the air interface, and processes it in the order opposite to that of the sending end. Among them, the processing of the data packet by each protocol layer is realized by the multi-functional entity corresponding to the protocol layer, for example, the processing of the PDCP layer is realized by the corresponding PDCP layer entity.

[0111] In a possible scenario, the access network device can be a base station, an evolved NodeB (eNodeB), an access point (AP), a TRP, a next generation NodeB (gNB), a base station in a future mobile communication system, or an access node in a WiFi system, etc. The access network device can be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in a CRAN scenario. Optionally, the access network device can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the access network device in the V2X technology can be a road side unit (RSU). All or part of the functions of the access network device in this application can also be implemented by software functions running on hardware, or by virtualized functions instantiated on a platform (such as a cloud platform). The access network device in this application can also be a logical node, a logical module or software that can implement all or part of the functions of the access network device.

[0112] In another possible scenario, multiple access network devices cooperate to assist a terminal to implement wireless access, and different access network devices respectively implement part of the functions of a base station. For example, the access network device can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a radio frequency remote unit (RRU), an active antenna processing unit (AAU), or a remote radio head (RRH).

[0113] As a first possible implementation, with reference to (a) in FIG. 9, the CU can be used to implement the functions of the RRC layer, the SDAP layer and the PDCP layer, the DU can be used to implement the functions of the RLC layer, the MAC layer and the PHY layer, and the DU communicates with the radio frequency unit through the PHY layer.

[0114] As a second possible implementation, referring to (b) in FIG. 9, the CU is configured to implement the functions of the RRC layer, the SDAP layer, and the PDCP layer, the DU is configured to implement the functions of the RLC layer, the MAC layer, the security layer, and the PHY layer, and the DU communicates with the radio frequency unit through the PHY layer, wherein the PDCP layer can implement the security function or can not implement the security function.

[0115] That is, the security function of the PDCP layer is implemented by sinking to the security layer arranged between the MAC layer and the PHY layer, or the security layer is arranged independently to implement the security function outside the PDCP layer, wherein the security layer can be a new protocol layer defined in advance by the protocol.

[0116] Optionally, the security layer can be used only to implement the security function (integrity check / protection and / or encryption / decryption function), or the security layer can implement the security function and the functions of packet assembly, packet splitting, adding a packet header, etc.

[0117] As a third possible implementation, referring to (c) in FIG. 9, the CU is configured to implement the functions of the RRC layer, the SDAP layer, and the PDCP layer, the DU is configured to implement the functions of the RLC layer, the MAC layer, and the PHY layer, and the DU communicates with the radio frequency unit through the PHY layer, wherein the PDCP layer can have the security function or can not contain the security function, and the security function is implemented by the lower layer of the MAC layer.

[0118] That is, the security function of the PDCP layer is implemented by sinking to the lower layer of the MAC layer, or the security function is added to the lower layer of the MAC layer.

[0119] As a fourth possible implementation, referring to (d) in FIG. 9, the CU is configured to implement the functions of the RRC layer, the SDAP layer, and the PDCP layer, the DU is configured to implement the functions of the RLC layer, the MAC layer, and the PHY layer, and the DU communicates with the radio frequency unit through the PHY layer, wherein the PDCP layer can have the security function or can not contain the security function, and the security function is implemented by the upper layer of the PHY layer.

[0120] That is, the security function of the PDCP layer is implemented by sinking to the upper layer of the PHY layer, or the security function is added to the upper layer of the PHY layer.

[0121] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, the CU can also be referred to as O-CU (open CU), the DU can also be referred to as O-DU, the CU-CP can also be referred to as O-CU-CP, the CU-UP can also be referred to as O-CU-UP, and the RU can also be referred to as O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0122] The terminal can also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. The terminal can be widely applied to various scenarios, such as D2D, V2X communication, MTC, IoT, virtual reality, augmented reality, industrial control, automatic driving, remote medical treatment, smart power grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal can be a mobile phone, tablet computer, computer with wireless transceiver function, wearable device, vehicle, unmanned aerial vehicle, helicopter, airplane, ship, robot, mechanical arm, smart home device, etc. The embodiments of the present application do not limit the device form of the terminal.

[0123] As a first possible implementation, referring to (a) in FIG. 10, the wireless protocol stack on the terminal side can include an RRC layer, an SDAP layer and a PDCP layer, an RLC layer, a MAC layer, a security layer and a PHY layer, and the PHY layer is connected with a radio frequency unit.

[0124] That is, the security function of the PDCP layer is implemented by sinking to the security layer arranged between the MAC layer and the PHY layer, or the security layer is independently arranged outside the PDCP layer to implement the security function, wherein the security layer can be a new protocol layer defined in advance by the protocol.

[0125] Optionally, the security layer can be used only to implement the security function (integrity check / protection and / or encryption / decryption function), or the security layer can implement the security function and the functions of packet assembly, packet splitting, adding packet header, etc.

[0126] As a second possible implementation, referring to (b) in FIG. 10, the wireless protocol stack on the terminal side can include an RRC layer, an SDAP layer and a PDCP layer, an RLC layer, a MAC layer and a PHY layer, and the PHY layer is connected with a radio frequency unit, wherein the PDCP layer can have a security function or can not contain the security function, and the security function is implemented by the underlying layer of the MAC layer.

[0127] That is, the security function of the PDCP layer is implemented at the bottom of the MAC layer, or a security function is added at the bottom of the MAC layer.

[0128] As a third possible implementation, with reference to (c) in FIG. 10, the wireless protocol stack at the terminal side can include an RRC layer, an SDAP layer and a PDCP layer, an RLC layer, a MAC layer and a PHY layer, the PHY layer being connected with a radio frequency unit, wherein the PDCP layer can have a security function or can not contain a security function, and the security function is implemented by the upper layer of the PHY layer.

[0129] That is, the security function of the PDCP layer is implemented at the upper layer of the PHY layer, or a security function is added at the upper layer of the PHY layer.

[0130] In a possible implementation, the security layer is located at L1 or the security function is implemented by the upper layer of the PHY layer, and the chip architecture diagram of the first communication device and / or the second communication device can refer to (a) in FIG. 11. The input and output interfaces of the L1 layer of the chip include a common public radio interface (CPRI) and an enhanced common public radio interface (eCPRI), the eCPRI being used to connect a transceiver module and a massive multiple input multiple output (Massive MIMO) antenna array, and the CPRI being used to connect a transceiver module and a radio equipment (RE). The L1 layer further includes a digital signal processor (DSP) for implementing a DCI security function, a processing module for implementing PDSCH and PUSCH security functions, and a control module of the L1 layer. The L2 layer includes processing modules for implementing PDCP layer packet compression and header adding functions, RLC layer functions and MAC layer functions, respectively. The L3 layer includes processing modules for implementing SDAP functions and PDCP layer PDCP SN allocation functions.

[0131] It is worth mentioning that the processing module for implementing PDSCH and PUSCH security functions can be a new processing module additionally arranged or a DSP.

[0132] In another possible implementation, the security layer is located at L1 and L2, or, in the case where the security function is implemented jointly by the upper layer of the PHY layer and the bottom layer of the MAC layer, the chip architecture diagram of the first communication apparatus and / or the second communication apparatus can refer to (b) in FIG. 11. The input / output interface in the L1 layer includes CPRI and eCPRI, the L1 layer includes a control module, a transceiver module, and a DSP for implementing the DCI security function. The L2 layer includes processing modules for implementing the PDCP layer data packet compression and header addition function, the RLC layer function, and the MAC layer function, respectively, and the processing module for implementing the MAC layer function is also used for implementing the security function of the PDSCH and the PUSCH. The L3 layer includes processing modules for implementing the SDAP function and the PDCP layer PDCP SN allocation function.

[0133] Referring to (c) in FIG. 11, the processing flow for implementing the security protection function of the data packet mainly includes: determining whether to start security protection according to the security indication; in the case where the security protection is started, determining the implementation manner of the security protection, for example, whether the data packet needs to be encrypted / decrypted, and / or whether the data packet needs to be integrity protected / verified. Then, according to the determined implementation manner of the security protection, performing the security protection operation on the physical layer data, and finally transmitting the data packet after the security protection operation to the next module.

[0134] It should be noted that the communication system described in the embodiments of the present application is for more clearly illustrating the technical solutions of the embodiments of the present application, and does not constitute a limitation on the technical solutions provided by the embodiments of the present application. It can be known by those skilled in the art that, with the evolution of network architecture and the appearance of new business scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0135] The communication method provided by the embodiments of the present application will be described below by taking the first communication apparatus and the second communication apparatus as an example, with reference to the communication system shown in FIG. 8. It should be noted that in the following embodiments of the present application, the message name between the first communication apparatus and the second communication apparatus, the name of each parameter, or the name of each information, etc. are only examples, and in other embodiments, they can also be other names, and the method provided by the present application does not make specific limitations on this.

[0136] It can be understood that in the embodiments of the present application, the first communication apparatus and the second communication apparatus can perform part or all of the steps in the embodiments of the present application, and these steps or operations are only examples, and the embodiments of the present application can also perform other operations or variations of various operations. In addition, each step can be executed in a different order as presented in the embodiments of the present application, and it is possible that not all the operations in the embodiments of the present application are executed.

[0137] It can be understood that the first communication device and the second communication device are taken as an example to illustrate the execution subject of the interaction in the present application, but the present application does not limit the execution subject of the interaction. For example, the method executed by the first communication device in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the first communication device, and can also be realized by a logical node, a logical module or software capable of realizing all or part of the function of the first communication device; the method executed by the second communication device in the present application can also be executed by a module (such as a chip, a chip system, or a processor) applied to the second communication device, and can also be realized by a logical node, a logical module or software capable of realizing all or part of the function of the second communication device.

[0138] In addition, "sending information" in the present application can be understood as that a device sends information to another device, or can also be understood as that a logical module in a device sends information to another logical module. For example, "the first communication device sends information" can be understood as that the first communication device sends information to another device (such as the second communication device), or can be understood as that a logical module 1 (such as a processing module) in the first communication device sends information to a logical module 2 (such as a transceiver module) in the first communication device.

[0139] "Receiving information" in the present application can be understood as that a device receives information from another device, or can also be understood as that a logical module in a device receives information from another logical module. For example, "the second communication device receives information" can be understood as that the second communication device receives information from another device (such as the first communication device), or can be understood as that a logical module 1 (such as a processing module) in the second communication device receives information from a logical module 2 (such as a transceiver module) in the second communication device.

[0140] "Sending information to … (such as the second communication device)" in the present application or the related illustration in the drawings can be understood as that the destination of the information is the second communication device. It can include directly or indirectly sending information to the second communication device. "Receiving information from … (such as the first communication device)" or "receiving information from … (such as the first communication device)" or "receiving information sent by … (such as the first communication device)", or the related illustration in the drawings can be understood as that the source of the information is the first communication device, which can include directly or indirectly receiving information from the first communication device. The information can be processed as necessary between the source and the destination of the information, such as format change, etc., but the destination can understand the valid information from the source. Similar expressions in the present application can be understood similarly, and will not be repeated here.

[0141] Referring to FIG. 12, FIG. 12 is a flowchart of a communication method provided by an embodiment of the present application, which can include the following steps:

[0142] S1201, the first communication device generates a first data packet according to the first COUNT. The first data packet is a data packet of a lower layer of a PDCP layer.

[0143] The first COUNT is determined according to a first HFN and a first air interface time corresponding to the first data packet. The first HFN is an HFN corresponding to the first air interface time.

[0144] For example, the first air interface time can be understood as an air interface time when the first data packet is transmitted, or can also be understood as an air interface time indicated by scheduling information of scheduling the first data packet. The first HFN can be understood as a value of an HFN maintained by the first communication device in the case where the air interface time is the first air interface time. In addition, the value of the HFN is maintained according to an initial value of the HFN and the air interface time. The initial value of the HFN and the specific maintenance manner are described in the following embodiments, and will not be described here.

[0145] As a possible implementation, the format of the COUNT can refer to (a) in FIG. 13. The COUNT can be an unsigned number of N bits composed of the HFN and the air interface time, where N is an integer greater than or equal to 1, for example, N is equal to 5, 8, 15, 20, 32, 45, 56, etc.

[0146] In (a) in FIG. 13, the HFN is taken as the first half of the COUNT, and the air interface time is taken as the second half of the COUNT as an example. In actual application, the order of the HFN and the air interface time can also be reversed, that is, the air interface time is taken as the first half of the COUNT, and the HFN is taken as the second half of the COUNT, which is not limited.

[0147] In a possible implementation, the air interface time includes at least one of the following: a frame number FN, a subframe number SFN, or a slot number (slot Num).

[0148] FN is a parameter used to identify the current air interface time between the base station and the terminal during the air interface transmission process, and its value range is 0-1023, which is issued by the base station to the terminal in the physical broadcast channel (PBCH). The value of FN increases by 1 represents an increase of 10 milliseconds (ms) in air interface time. SFN is used to identify the current air interface time in which the current air interface time is in the first subframe, and its value range is 0-9. The value of SFN increases by 1 represents an increase of 1 ms in air interface time; the time slot number is used to identify the current air interface time in which the current air interface time is in the first time slot. The number of time slots in each SFN and the time length corresponding to each time slot are determined by the frame structure of the air interface. For example, in the 30K subcarrier scenario, the number of time slots in one SFN is 2, the value of the time slot number is 0 or 1, and the time slot number increases by 1 represents an increase of 0.5 ms in air interface time.

[0149] Generally, during the air interface transmission process, the current air interface time can be recorded in units of time length of one time slot by combining FN, SFN and time slot number, and the maximum effective time length that can be recorded is 10.24 seconds.

[0150] For example, taking the air interface time including FN, SFN and time slot number as an example, the format of COUNT can refer to (b) in FIG. 13. HFN is the first half of COUNT, and FN, SFN and time slot number in the air interface time are collectively used as the second half of COUNT.

[0151] It is worth mentioning that (b) in FIG. 13 is an example of air interface time arranged in order by FN, SFN and time slot number. In the application process, the order of FN, SFN and time slot number can also be changed, for example, the order of each element in the air interface time is changed to time slot number, FN and SFN, or changed to SFN, time slot number and FN, etc. without limitation.

[0152] In addition, COUNT is the unique identification information of the data packet of the security algorithm key stream block. COUNT can also be referred to as a unique identifier (identity document, ID) corresponding to the data packet, a data packet number corresponding to the data packet, or a sequence (number once, Nonce) corresponding to the data packet, etc. The naming of COUNT is not limited.

[0153] Among them, generating a first data packet according to the first COUNT can be understood as performing integrity protection and / or encryption on the to-be-transmitted data according to the first COUNT to obtain the first data packet.

[0154] For example, the to-be-transmitted data is integrity-protected according to the first COUNT, and the to-be-transmitted data is encrypted according to the first COUNT to obtain the first data packet; or the to-be-transmitted data is integrity-protected according to the first COUNT to obtain the first data packet; or the to-be-transmitted data is encrypted according to the first COUNT to obtain the first data packet.

[0155] As a possible implementation, in a case where the first data packet is a DCI data packet, the first air interface time is an air interface time for transmitting the first data packet, and the generation of the first data packet according to the first COUNT can be understood as integrity protection of to-be-transmitted DCI information according to the first COUNT, and then the first data packet is generated.

[0156] As another possible implementation, in a case where the first data packet is a PDSCH data packet or a PUSCH data packet, the first air interface time can be an air interface time for transmitting the first data packet or an air interface time indicated by scheduling information for scheduling the first data packet. The generation of the first data packet according to the first COUNT can be encryption and / or integrity protection of to-be-transmitted uplink data or downlink data according to the first COUNT, and then the first data packet is generated.

[0157] In the embodiments of the present application, the implementation manner of integrity protection of to-be-transmitted data according to the first COUNT and encryption of to-be-transmitted data according to the first COUNT is similar to the implementation manner of integrity protection and encryption of a data packet by the PDCP layer based on a COUNT and a security algorithm in the foregoing embodiments, and reference can be made to the related description in the foregoing embodiments. The difference lies in the determination manner of the COUNT, which will not be described herein again.

[0158] The first data packet is an initial transmission data packet. For example, the first data packet being an initial transmission data packet can be understood as that the first data packet is first exchanged between the first communication device and the second communication device, or the content of the first data packet is different from the content of a data packet transmitted before the first data packet is transmitted.

[0159] For example, the first data packet being a data packet of a lower layer of the PDCP layer can be understood as that the first data packet is a data packet generated by the PDCP layer or a lower protocol layer of the PDCP layer, or can also be understood as that the first data packet is a service data unit (SDU) received by the lower protocol layer of the PDCP layer, or can also be understood as that the first data packet is a protocol data unit (PDU) generated by the lower protocol layer of the PDCP layer after implementing a protocol layer function.

[0160] For example, in the case that the wireless protocol stack does not include the newly added security layer, or the wireless protocol stack includes the newly added security layer and the security layer does not have the packet assembling or packet splitting function, the first data packet can be a data packet generated by the PDCP layer, a data packet generated by the RLC layer, a data packet generated by the MAC layer, or a data packet generated by the PHY layer; or the first data packet can also be an RRC PDU (also referred to as a PDCP SDU), a PDCP PDU (also referred to as an RLC SDU), a MAC SDU, a MAC PDU (also referred to as a PHY SDU), or a PHY PDU (such as DCI), etc.

[0161] For example, in the case that the wireless protocol stack does not include the newly added security layer, or the wireless protocol stack includes the newly added security layer and the security layer does not have the packet assembling or packet splitting function, the first data packet can be a data packet generated by the PDCP layer, a data packet generated by the RLC layer, a data packet generated by the MAC layer, or a data packet generated by the PHY layer; or the first data packet can also be an RRC PDU (also referred to as a PDCP SDU), a PDCP PDU (also referred to as an RLC SDU), a MAC SDU, a MAC PDU (also referred to as a PHY SDU), or a PHY PDU (such as DCI), etc.

[0162] For the convenience of description, the first data packet is taken as a PHY PDU in the following embodiments of the present application, and the first data packet can also be a PDU or a SDU of other protocol layers in the application.

[0163] Step S1202, the first communication device sends the first data packet to the second communication device. Correspondingly, the second communication device receives the first data packet from the first communication device.

[0164] For example, after determining the air interface time for sending the first data packet to the second communication device, the first communication device sends the first data packet to the second communication device at the air interface time, and the second communication device can receive the first data packet from the first communication device at the air interface time according to the previously received scheduling information or periodic channel scanning.

[0165] For example, in the case that the first data packet is a DCI data packet, the first communication device sends the first data packet through the PDCCH, and the second communication device acquires the first data packet through PDCCH blind detection. For example, in the case that the first data packet is a PDSCH data packet or a PUSCH data packet, the second communication device acquires the first data packet at the air interface time indicated by the previously received or sent scheduling information.

[0166] In step S1203, the second communication apparatus performs security detection on the first data packet according to the first COUNT.

[0167] The meaning of the first COUNT can refer to the related description in the foregoing embodiments, and will not be described again. In the process of determining the first COUNT, the second communication apparatus can take the air interface time of receiving the first data packet or the air interface time indicated by the scheduling information of scheduling the first data packet as the first air interface time, and take the value of the maintained HFN at the first air interface time as the first HFN.

[0168] For example, in the process of obtaining the first COUNT, when the first data packet is a DCI data packet, the second communication apparatus can take the air interface time of receiving the first data packet as the first air interface time; when the first data packet is a PDSCH data packet or a PUSCH data packet, the first air interface time can be the air interface time when the first data packet is received, or the air interface time indicated by the scheduling information of scheduling the first data packet.

[0169] For example, performing security detection on the first data packet according to the first COUNT can be understood as performing decryption on the first data packet according to the first COUNT; or performing integrity verification on the first data packet according to the first COUNT; or performing integrity verification and decryption on the first data packet according to the first COUNT.

[0170] As a possible implementation, when the first data packet is a DCI data packet, the first air interface time is the air interface time of transmitting the first data packet, and performing security detection on the first data packet according to the first COUNT can be understood as performing integrity verification on the first data packet according to the first COUNT.

[0171] As another possible implementation, when the first data packet is a PDSCH data packet or a PUSCH data packet, the first air interface time can be the air interface time when the first data packet is transmitted, or the air interface time indicated by the scheduling information of scheduling the first data packet. Performing security detection on the first data packet according to the first COUNT can be performing decryption and / or integrity verification on the first data packet according to the first COUNT.

[0172] In the embodiments of the present application, the implementation of performing integrity verification on the first data packet according to the first COUNT and performing decryption on the first data packet according to the first COUNT is similar to the implementation of the PDCP layer performing integrity verification and decryption on the data packet based on the COUNT and the security algorithm in the foregoing embodiments, and the related description in the foregoing embodiments can be referred to, and will not be described again.

[0173] It is worth mentioning that, since the terminal will achieve the air interface time synchronization with the base station according to the system information broadcasted by the base station in the random access process, the first communication device and the second communication device have the same understanding of the first air interface time corresponding to the first data packet; in the case that the first communication device and the second communication device maintain the HFN according to the air interface time in the same way and the initial value of the HFN is the same, the first communication device and the second communication device also have the same understanding of the first HFN corresponding to the first air interface time of the first data packet. That is, the COUNT used by the first communication device in the process of generating the first data packet and the COUNT used by the second communication device in the process of integrity checking and / or decryption of the first data packet are the same.

[0174] Based on the scheme, the embodiment of the present application provides a communication method, in the process of interaction of the first communication device and the second communication device for the data packet (first data packet) of the lower layer of the PDCP layer, the first communication device can perform integrity protection and / or encryption on the first data packet based on the first COUNT, and the second communication device performs integrity checking and / or decryption on the first data packet based on the first COUNT, thereby achieving the security protection of the data packet of the lower layer of the PDCP layer, which is conducive to reducing the risk of forgery and tampering of the data / signaling of the lower layer of the PDCP layer; the first COUNT is determined according to the first HFN and the first air interface time corresponding to the first data packet, and the first HFN is the HFN corresponding to the first air interface time, that is, the determination of the first COUNT mainly depends on the air interface time corresponding to the first data packet. Since the first communication device and the second communication device performing air interface communication through the wireless protocol stack will keep the air interface time synchronized, in the case of interaction of the first data packet, the first air interface time can be determined based on the air interface time of transmitting the first data packet or the scheduling information of scheduling the first data packet, without the need to carry the indication information for determining the first COUNT in the first data packet, which is conducive to achieving the security protection of the first data packet without increasing the air interface overhead or increasing a small amount of air interface overhead.

[0175] The overall flow of the communication method provided by the present application is described above, and the specific implementation of each step is introduced below.

[0176] In a possible implementation, before step S1201, the first communication device transmits or receives the first scheduling information. Correspondingly, the second communication device receives or transmits the first scheduling information. The first scheduling information is used for scheduling the first data packet, and the first scheduling information indicates the first air interface time.

[0177] Exemplarily, in a case that the first communication device is a base station and the second communication device is a terminal, the first communication device transmits the first scheduling information, and the second communication device receives the first scheduling information; in a case that the first communication device is a terminal and the second communication device is a base station, the first communication device receives the first scheduling information, and the second communication device transmits the first scheduling information.

[0178] The first scheduling information can be understood as DCI scheduling the first data packet, or can also be understood as information contained in a field in the DCI scheduling the first data packet for indicating air interface time. The first scheduling information indicating the first air interface time can be understood as that the first air interface time is determined according to the air interface time indicated by the first scheduling information.

[0179] Optionally, determining the first air interface time according to the air interface time indicated by the first scheduling information includes the following two possible implementation manners:

[0180] Manner one, the first air interface time is the air interface time indicated by the first scheduling information.

[0181] For example, taking the first scheduling information as DCI as an example. The DCI contains K0 field and K2 field, and the air interface time indicated by the first scheduling information can be understood as air interface time with a time domain interval length of T between the air interface time of transmitting the DCI, T is the time domain interval length indicated by the K0 field, or T is the time domain interval length indicated by the K2 field.

[0182] That is, the first air interface time is air interface time with a time domain interval length equal to T between the air interface time of the DCI scheduling the first data packet.

[0183] Manner two, the interval between the first air interface time and the air interface time indicated by the first scheduling information is equal to an air interface time offset value.

[0184] For example, taking the first scheduling information as DCI as an example, the DCI includes K0 field, K2 field and preset offset field, and the preset offset field is used to indicate the air interface time offset value (denoted as T1). The air interface time indicated by the first scheduling information (denoted as T2) can be understood as air interface time with a time domain interval length of T between the air interface time of transmitting the DCI, T is the time domain interval length indicated by the K0 field, or T is the time domain interval length indicated by the K2 field.

[0185] Exemplarily, the air interface time offset value can be a value greater than or equal to 0, for example, 0, 2, 4, 7 or 9, etc.

[0186] That is, the first air interface time is an air interface time with a time domain interval length between the first air interface time and T2 equal to T1. In a case where the air interface time offset value is equal to 0, the first air interface time is the air interface time indicated by the first scheduling information. In a case where the air interface time offset value is greater than 0, the first air interface time is an air interface time with a time domain interval length between the first air interface time and T2 equal to T1, which can be understood as that the first air interface time is earlier than T2 and has a time domain interval length equal to T1 between the first air interface time and T2, or can also be understood as that the first air interface time is later than T2 and has a time domain interval length equal to T1 between the first air interface time and T2.

[0187] In addition, the air interface time offset value can also be an arbitrary value, for example, in a case where the first air interface time is earlier than T2, the air interface time offset value is a negative number, and in a case where the first air interface time is later than T2, the air interface time offset value is a positive number; or in a case where the first air interface time is earlier than T2, the air interface time offset value is a positive number, and in a case where the first air interface time is later than T2, the air interface time offset value is a negative number.

[0188] The preset offset field can be a field defined in advance by a protocol, or can also be a field agreed upon in advance by the first communication device and the second communication device.

[0189] It is worth mentioning that the above embodiment is described by taking an example in which the preset offset field indicating the air interface time offset value is located in the first scheduling information. In application, the air interface time offset value can also be defined in advance by a protocol or agreed upon in advance by the first communication device and the second communication device, or can also be carried in other indication information exchanged between the first communication device and the second communication device, without limitation.

[0190] In a possible implementation, before step S1201, the first communication device transmits or receives first indication information. Correspondingly, the second communication device receives or transmits the first indication information. The first indication information is used to determine whether the first air interface time is the air interface time indicated by the first scheduling information.

[0191] The implementation manner of the first communication device and the second communication device exchanging the first indication information is similar to the implementation manner of the first communication device and the second communication device exchanging the first scheduling information, and reference can be made to the related description in the foregoing embodiments, which will not be described herein again.

[0192] For example, the first indication information is used to determine whether the first air interface time is the air interface time indicated by the first scheduling information, which can be understood as that the first indication information is used to indicate whether the first data packet is an initial transmission data packet, and the meaning of the initial transmission data packet can be referred to the related description in the foregoing embodiments, or can also be understood as that the first indication information is used to indicate whether the RV corresponding to the first data packet is RV0.

[0193] As a possible implementation, the first indication information is carried in the NDI identifier in the DCI.

[0194] In the case that the first indication information is carried in the NDI identifier, the first communication device and the second communication device detect whether the current NDI identifier is in the same state as the NDI identifier in the last DCI. In the case that the NDI identifier is in a different state from the NDI identifier in the last DCI, the first indication information indicates that the first data packet is the initial transmission data packet, or in other words, the first indication information indicates that the first air interface time is the air interface time indicated by the first scheduling information.

[0195] As another possible implementation, the first indication information is carried in the RV field in the DCI.

[0196] In the case that the first indication information is carried in the RV field, the first communication device and the second communication device detect the RV value corresponding to the RV field in the DCI scheduling the first data packet. In the case that the RV field is set to 0, the first indication information indicates that the RV corresponding to the first data packet is RV0, or in other words, the first indication information indicates that the first air interface time is the air interface time indicated by the first scheduling information.

[0197] Optionally, the first indication information and the first scheduling information can be carried in the same message. For example, the first indication information is carried in the RV field or the NDI identifier in the DCI, and the first scheduling information is carried in the K0 field and / or the K2 field in the DCI. In the case that the first indication information and the first scheduling information are carried in the same message, it is beneficial to reduce the signaling overhead in scheduling the first data packet, and it is possible to reduce the protocol modification amount caused by implementing data packet security protection based on the first COUNT as much as possible.

[0198] In a possible implementation, the first communication device sends a retransmission data packet of the first data packet to the second communication device. Correspondingly, the second communication device receives the retransmission data packet of the first data packet from the first communication device. The first communication device and the second communication device implement the secure interaction of the information corresponding to the first data packet through the retransmission data packet of the first data packet.

[0199] For example, the first communication device sends the retransmission data packet of the first data packet to the second communication device in the case that the second communication device fails to successfully decode the first data packet, or the first communication device sends the retransmission data packet of the first data packet to the second communication device in the case that the second communication device fails to successfully demodulate the first data packet, or the first communication device sends the retransmission data packet of the first data packet to the second communication device in the case that the second communication device fails to successfully receive the first data packet.

[0200] The first communication device and the second communication device realize the secure interaction of the information corresponding to the first data packet through the retransmission data packet of the first data packet, which can include the following two possible implementation manners:

[0201] Manner one, the first communication device sends a second data packet to the second communication device, and the second data packet is a retransmission data packet of the first data packet. Correspondingly, the second communication device receives the second data packet from the first communication device and performs security detection on the second data packet according to the first COUNT.

[0202] For example, the second data packet being a retransmission data packet of the first data packet can be understood as that the content of the second data packet is the same as that of the first data packet, and the second data packet is a data packet that is integrity protected and / or encrypted according to the first COUNT, that is, the second data packet is completely the same as the first data packet; or, it can also be understood that the NDI identifier in the DCI scheduling the second data packet and the NDI identifier in the DCI scheduling the first data packet are set to the same state.

[0203] For example, the second communication device performing security detection on the second data packet according to the first COUNT can be understood as performing integrity verification on the second data packet according to the first COUNT, and / or performing decryption on the second data packet according to the first COUNT.

[0204] The implementation manner of the first communication device generating the second data packet according to the first COUNT is similar to the implementation manner of the first communication device generating the first data packet according to the first COUNT in the foregoing embodiment, and the related description in the foregoing embodiment can be referred to, and will not be described herein again. Similarly, the implementation manner of the second communication device performing security detection on the second data packet according to the first COUNT is similar to the implementation manner of the second communication device performing security detection on the second data packet according to the first COUNT in the foregoing embodiment, and the related description in the foregoing embodiment can be referred to, and will not be described herein again.

[0205] The security protection of the second data packet according to the first COUNT can include the following two possible implementation manners:

[0206] Manner 1, performing security protection on the second data packet according to the pre-stored first COUNT.

[0207] That is, the first communication device and the second communication device record the first COUNT corresponding to the first data packet according to a preset rule after obtaining the first COUNT corresponding to the first data packet, and in a case where the second communication device fails to successfully parse the first data packet, the first communication device generates a second data packet according to the first COUNT corresponding to the first data packet, and after the second communication device receives the retransmission data packet (the second data packet) of the first data packet according to the scheduling information, the second communication device performs security detection on the second data packet according to the first COUNT corresponding to the first data packet.

[0208] The preset rule can be understood as a data processing rule defined in advance by a protocol, or can also be understood as a data processing rule agreed in advance by the first communication device and the second communication device.

[0209] For example, taking the first communication device as a base station and the second communication device as a terminal as an example. The first data packet is a first transmission data packet in a PDSCH channel. Referring to FIG. 14, the base station sends a message containing a DCI and a PDSCH data packet (the first data packet) to the terminal at an air interface time (FN=21, SFN=0, time slot number=0). The DCI indicates that the air interface time of the first data packet is (FN=21, SFN=0, time slot number=0). The HFN corresponding to the air interface time (FN=21, SFN=0, time slot number=0) is 0. Since the DCI and the first data packet are both first transmission data packets, the HFN in the first COUNT corresponding to the DCI and the first data packet is 0, and the air interface time is FN=21, SFN=0, time slot number=0.

[0210] After the terminal correctly receives the DCI according to the first COUNT, the terminal receives the first data packet at the air interface time (FN=21, SFN=0, time slot number=0) according to the indication of the DCI, and performs decoding and other operations on the first data packet. In a case where the terminal fails to correctly decode or demodulate the first data packet, the terminal feeds back a NACK to the base station. After the base station receives the NACK from the terminal, the base station generates a second data packet according to the first COUNT corresponding to the first data packet, and sends a message containing a new DCI and the second data packet to the terminal at a new air interface time (FN=21, SFN=4, time slot number=0). The DCI indicates that the air interface time of the second data packet is FN=21, SFN=4, time slot number=0.

[0211] Since the HFN corresponding to the air interface time (FN=21, SFN=4, time slot number=0) is also 0, the HFN in the first COUNT corresponding to the DCI and the second data packet is 0, the DCI is a new DCI for initial transmission, and therefore the air interface time corresponding to the DCI is FN=21, SFN=4, time slot number=0, the second data packet is a retransmission data packet of the first data packet, and therefore the air interface time in the COUNT corresponding to the second data packet is FN=21, SFN=0, time slot number=0. After the terminal correctly receives the DCI according to the COUNT corresponding to the DCI, the terminal receives the second data packet at the air interface time FN=21, SFN=4, time slot number=0, determines that the second data packet is a retransmission data packet of the first data packet according to the DCI, and successfully decodes the second data packet, feeds back ACK to the base station, and performs security detection on the second data packet according to the COUNT (the first COUNT) corresponding to the first data packet.

[0212] In addition, the above is described by taking the first communication device as a base station, and in the case where the first communication device is a terminal, the base station sends, to the terminal, a DCI indicating retransmission of the first data packet when the base station fails to successfully decode or demodulate the first data packet, the terminal receives the DCI, and sends, to the base station, a second data packet generated according to the first COUNT at a data packet transmission time indicated by the DCI according to a preset rule, and the base station performs security detection on the second data packet according to the first COUNT. The specific implementation manner is similar to that in the above embodiment, and will not be described herein again.

[0213] Based on the scheme, the first communication device and the second communication device perform security protection on the transmission data packet (the second data packet) of the first data packet based on the first COUNT corresponding to the first data packet, so that retransmission of the first data packet that is protected according to the first COUNT meets the requirements of the HARQ mechanism in the current protocol, and the influence of the security protection function according to the first COUNT on the HARQ mechanism is reduced.

[0214] Option 2: performing security protection on the second data packet through the first COUNT according to the second scheduling information and the second indication information.

[0215] As a possible implementation, the first communication device sends or receives the second indication information and the second scheduling information when the second communication device fails to successfully decode or demodulate the first data packet. Correspondingly, the second communication device receives or sends the second indication information and the second scheduling information.

[0216] The implementation manners of the first communication device and the second communication device interacting with the second scheduling information and the second indication information are similar to the implementation manners of the first communication device and the second communication device interacting with the first scheduling information and the first indication information, and the related descriptions in the foregoing embodiments can be referred to, which will not be repeated here.

[0217] The second scheduling information is used for scheduling the second data packet, and the second scheduling information indicates the second air interface time.

[0218] For example, the second scheduling information can be understood as DCI scheduling the second data packet, or can also be understood as information contained in a field in the DCI scheduling the second data packet for indicating the second air interface time. The second scheduling information indicating the second air interface time can be understood as that the second air interface time is determined according to the air interface time indicated by the second scheduling information.

[0219] The implementation manner of the second scheduling information indicating the second air interface time is similar to the implementation manner of the first scheduling information indicating the first air interface time, and the related descriptions in the foregoing embodiments can be referred to, which will not be repeated here.

[0220] The second indication information is used for determining the COUNT corresponding to the second data packet.

[0221] For example, the second indication information indicates a first offset and / or a second offset. The air interface time in the COUNT corresponding to the second data packet is determined according to the second air interface time and the first offset, or the air interface time in the COUNT corresponding to the second data packet is determined according to the second air interface time, the first offset and the second offset.

[0222] The first offset is an offset between the first air interface time and the second air interface time; and the second offset is an offset between the first HFN and the second HFN, and the second HFN is an HFN corresponding to the second air interface time.

[0223] For example, the second indication information indicates the first offset. In the process of the first communication device and the second communication device determining the COUNT corresponding to the second data packet according to the second indication information, an air interface time (denoted as T3) with a time domain interval length between the second air interface time indicated by the second scheduling information and the second air interface time being the first offset is taken as an air interface time constituting the COUNT corresponding to the second data packet. Since the first offset is an offset between the first air interface time corresponding to the first data packet and the second air interface time indicated by the second scheduling information, T3 is the air interface time (the first air interface time) corresponding to the first data packet. The COUNT corresponding to the second data packet determined according to T3 is the same as a COUNT (the first COUNT) determined according to the first air interface time and a first HFN corresponding to the first air interface time.

[0224] For example, the second indication information indicates the first offset and the second offset. In determining the COUNT corresponding to the second data packet according to the second indication information, in the case that the second offset is 0, the time interval length between the second air interface time indicated by the second scheduling information and the current HFN corresponding air interface time is the first offset, the air interface time (denoted as T3) with the time interval length of the first offset between the second air interface time and the current HFN corresponding air interface time is directly taken as the air interface time constituting the COUNT corresponding to the second data packet; in the case that the second offset is 1, the air interface time (denoted as T3) with the time interval length of the first offset between the second air interface time and the air interface time corresponding to the previous HFN or the next HFN is taken as the air interface time constituting the COUNT corresponding to the second data packet.

[0225] Since the first offset is the offset between the first air interface time corresponding to the first data packet and the second air interface time indicated by the second scheduling information, T3 is exactly the first air interface time. Therefore, the COUNT determined according to T3 and the HFN corresponding to T3 can also be understood as the first COUNT determined according to the first air interface time and the first HFN corresponding to the first air interface time, i.e., the COUNT corresponding to the second data packet is the first COUNT.

[0226] As a possible implementation, the second indication information and the second scheduling information are contained in the same message. For example, referring to (a) in FIG. 15, the second indication information is carried in the preset offset field in the DCI, and the second scheduling information is carried in the K2 and K0 fields in the DCI scheduling the second data packet. Alternatively, the second indication information is carried in the preset offset field in the DCI, and the second scheduling information is the DCI scheduling the second data packet.

[0227] As another possible implementation, the second indication information and the second scheduling information are contained in different messages. For example, referring to (b) in FIG. 15, the second scheduling information is the DCI scheduling the second data packet, or the second scheduling information is carried in the K2 and K0 fields in the DCI scheduling the second data packet; the second indication information is carried in the packet header of the second data packet, and the packet header of the second data packet is only integrity protected but not encrypted.

[0228] It is worth mentioning that, since the upper limit of the scheduling unit time (TTI) of the interval between the retransmission data packet and the initial transmission data packet is usually less than 100, and the number of TTIs corresponding to one HFN is usually much greater than 100, the value of the second offset is usually 0 or 1. In the case where the second indication information explicitly indicates the first offset and the second offset, the second offset can be indicated by one bit, and the first offset can be indicated by 8 bits, that is, the COUNT corresponding to the second data packet can be indicated by an additional 9 bits. In the scheme of adding SN for each data packet, each message needs to occupy at least 12 to 18 additional bits, and therefore, the scheme in the embodiment of the present application is beneficial to reduce the air interface overhead caused by the security protection of the full protocol stack data packet.

[0229] In addition, referring to (c) in FIG. 15, since the frame structure and scheduling rules of the system do not change in real time, the retransmission timing of the data retransmission in the application of the data retransmission technology (such as HARQ) is regular, and the number of data retransmissions has a clear upper limit. Therefore, in the case where the frame structure is fixed, the interval between the air interface time corresponding to the initial transmission data packet and the retransmission data packet can only be a few fixed intervals, usually 4 to 8.

[0230] Therefore, in the case where the second indication information implicitly indicates the first offset, the interval between the first data packet and the second data packet can be indicated by 2 or 3 bits (for example, indicating the index corresponding to the fixed interval). Among them, the specific interval value of each fixed interval can be defined in advance by the protocol, or sent to the terminal by the base station in advance through the RCC message. That is, in the case where the second indication information implicitly indicates the first offset, the COUNT corresponding to the second data packet can be indicated by 2 or 3 bits, which significantly reduces the air interface overhead caused by the security protection of the full protocol stack data packet.

[0231] Based on the scheme, in the process of the first communication device and the second communication device interacting with the second data packet, the first COUNT corresponding to the first data packet can be used as the COUNT corresponding to the second data packet to protect the security of the second data packet according to the second scheduling information and the second indication information, avoiding the problem that the content of the second data packet is inconsistent with the first data packet after the second data packet is protected according to the COUNT corresponding to the second data packet indicated by the DCI scheduling the second data packet, so that the second data packet transmission meets the requirements of the current data retransmission mechanism (such as HARQ), and the influence of the security protection of the full protocol stack data packet according to the COUNT corresponding to the data packet on the retransmission mechanism is minimized.

[0232] In the second mode, the first communication device generates a third data packet according to the second COUNT and sends the third data packet to the second communication device. Correspondingly, the second communication device receives the third data packet from the first communication device and performs security detection on the third data packet according to the second COUNT. The third data packet is a retransmission data packet of the first data packet.

[0233] For example, the third data packet being a retransmission data packet of the first data packet can be understood as that the third data packet corresponds to the same information element as the first data packet, or the third data packet contains the same information as the first data packet, or the NDI in the DCI scheduling the first data packet and the NDI in the DCI scheduling the third data packet are set to the same state.

[0234] The second COUNT is determined according to a third HFN and a third air interface time corresponding to the third data packet, and the third HFN is an HFN corresponding to the third air interface time.

[0235] For example, the third air interface time can be understood as the air interface time when the third data packet is transmitted, or can also be understood as the air interface time indicated by the scheduling information of the third data packet. The third HFN can be understood as the value of the HFN maintained by the first communication device at the air interface time of the third air interface time.

[0236] The manner of determining the second COUNT according to the third HFN and the third air interface time corresponding to the third data packet is similar to the manner of determining the first COUNT according to the first HFN and the first air interface time in the foregoing embodiments, and the relevant description in the foregoing embodiments can be referred to. The difference is that the first air interface time is replaced by the third air interface time, and the first HFN is replaced by the third HFN, and thus the description is not repeated.

[0237] As a possible implementation, the first communication device is a base station, and the second communication device is a terminal. After the first communication device sends the first data packet to the second communication device, if the first communication device does not receive ACK or NACK fed back by the second communication device at the air interface time indicated by the scheduling information of the first data packet for feeding back the transmission result of the first data packet, the first communication device sends the third data packet generated according to the second COUNT to the second communication device at the third air interface time.

[0238] For example, the base station does not receive the ACK and NACK feedback from the second communication device, which can be understood as the base station sending the first data packet to the terminal missing the scheduling information (e.g., DCI), so the terminal does not feedback the ACK or NACK; or it can also be understood as the terminal successfully receiving the scheduling information of the first data packet and the first data packet, and the ACK or NACK feedback is lost in the transmission process (i.e., the response information is lost); or it can also be understood as the terminal successfully receiving the scheduling information of the first data packet, and unsuccessfully receiving the first data packet, so it does not feedback the ACK or NACK to the base station.

[0239] For example, taking the first communication device as the base station and the second communication device as the terminal, and taking the first data packet as a first data packet in a PDSCH channel, as shown in (a) of FIG. 16, the base station sends a message containing DCI and a PDSCH data packet (first data packet) to the terminal at a first air interface time. The DCI indicates that the air interface time where the first data packet is located is (FN=22, SFN=6, slot number=0). Since the HFN corresponding to the air interface time (FN=22, SFN=0, slot number=0) is 0, the first HFN in the first COUNT corresponding to the DCI and the first data packet is 0, and the corresponding first air interface time is FN=22, SFN=6, slot number=0.

[0240] In the case of missing the DCI, the terminal cannot receive the first data packet at the first air interface time indicated by the DCI, and will not feedback the ACK or NACK to the base station. After the base station sends the DCI and the first data packet, if the base station does not receive the feedback information from the terminal at the air interface time where the decoding and / or demodulation result of the first data packet is fed back, the base station sends a retransmission data packet to the terminal based on the retransmission mechanism. If the base station retransmits the retransmission data packet generated according to the first COUNT to the terminal at a new air interface time (FN=23, SFN=0, slot number=0) based on the current retransmission mechanism, the terminal will consider the retransmission data packet as a first data packet after receiving the retransmission data packet, because the terminal does not receive the DCI and the first data packet sent by the base station at the first air interface time, and determine the COUNT corresponding to the retransmission data packet according to the air interface time (FN=23, SFN=0, slot number=0) corresponding to the retransmission data packet and the HFN corresponding to the air interface time. In this case, the terminal and the base station understand the COUNT corresponding to the retransmission data packet differently, and the terminal cannot implement the integrity verification and decryption of the retransmission data packet.

[0241] Therefore, referring to (b) in FIG. 16, in the process that the base station sends the retransmission data packet to the terminal based on the retransmission mechanism, the base station can first determine the third air interface time (FN=23, SFN=0, time slot number=0) for retransmitting the first data packet according to the preset rule, and determine the HFN corresponding to the third data packet according to the third air interface time. Then the base station sends a message containing a new DCI and the third data packet generated according to the second COUNT to the terminal at the third air interface time (FN=23, SFN=0, time slot number=0), and the DCI indicates that the air interface time where the third data packet is located is FN=23, SFN=0, and time slot number=0. The meaning of the preset rule can be referred to the related description in the foregoing embodiments, and will not be described here.

[0242] Since the terminal does not receive the message sent by the base station at the air interface time (FN=22, SFN=6, time slot number=0), the DCI and the third data packet sent by the base station at the air interface time (FN=23, SFN=0, time slot number=0) are initial transmission data for the terminal. After receiving the message from the base station, the terminal takes the air interface time (FN=23, SFN=0, time slot number=0) as the air interface time corresponding to the DCI and the third data packet, and since the HFN corresponding to the air interface time (FN=23, SFN=0, time slot number=0) is also 0, the terminal sets the HFN in the COUNT corresponding to the DCI and the third data packet to 0. After successfully receiving the third data packet according to the DCI, the terminal feeds back ACK to the base station, and performs integrity verification and / or decryption on the third data packet based on the COUNT (second COUNT) determined according to the air interface time (FN=23, SFN=0, time slot number=0).

[0243] The foregoing embodiments are described by taking the case that the terminal does not receive the message sent by the base station at the first air interface time as an example, and in the case that the terminal fails to receive the first data packet at the first air interface time according to the scheduling information of the first data packet, the retransmission of the first data packet can refer to the description of the foregoing embodiments.

[0244] Based on the scheme, in the process that the first communication device and the second communication device interact information corresponding to the first data packet, in the case that the scheduling information is lost, the first data packet is lost, or the response information (ACK / NACK) is lost, in the process that the first communication device and the second communication device retransmit the information corresponding to the first data packet, the first communication device and the second communication device can take the first retransmission data packet as a new initial transmission data packet, implement security protection on the data packet according to the air interface time (third air interface time) corresponding to the data packet, and avoid the problem of inconsistent understanding of the COUNT used by the first communication device and the second communication device in the process of implementing security protection on the third data packet.

[0245] Further, in the case that the ACK or NACK fed back by the terminal is lost, or in the case that the first data packet is an uplink data packet and the base station does not receive the first data packet after sending the scheduling information of the first data packet, the base station can further send third scheduling information to the terminal, and the third scheduling information indicates that the COUNT corresponding to the retransmission data packet (third data packet) of the first data packet is determined according to the third air interface time and the third HFN.

[0246] That is, the first communication device generates the third data packet according to the third scheduling information and the second COUNT. Correspondingly, the second communication device performs security detection on the third data packet according to the third scheduling information and the second COUNT.

[0247] Optionally, the first communication device sends or receives the third scheduling information. Correspondingly, the second communication device receives or sends the third scheduling information.

[0248] The third scheduling information is used for scheduling the third data packet, and the third scheduling information indicates the third air interface time and the RV corresponding to the third data packet as RV0.

[0249] For example, the third scheduling information can be understood as the DCI scheduling the third data packet, or can also be understood as the information contained in the field indicating the third air interface time and the RV field in the DCI scheduling the third data packet. The third scheduling information indicating the third air interface time can be understood as that the third air interface time is determined according to the air interface time indicated by the third scheduling information. The RV corresponding to the third data packet is indicated by the RV field in the DCI.

[0250] The implementation manner of the third scheduling information indicating the third air interface time is similar to the implementation manner of the first scheduling information indicating the first air interface time in the foregoing embodiments, and can refer to the related description in the foregoing embodiments, which will not be described herein. The manner of the first communication device and the second communication device interacting the third scheduling information is similar to the manner of the first communication device and the second communication device interacting the first scheduling information in the foregoing embodiments, and can refer to the related description in the foregoing embodiments, which will not be described herein.

[0251] For example, taking the first communication device as a base station and the second communication device as a terminal as an example, the base station sends a message containing DCI and PDSCH data packets (first data packets) to the terminal at a first air interface time. In the case where no feedback information from the terminal is received at the air interface time for feeding back the decoding and / or demodulation result of the first data packets, the base station enters a discontinuous transmission (DTX) mode according to the protocol and starts a retransmission data packet (third data packet) sending process of the first data packets. After the base station determines the air interface time (third air interface time) for transmitting the third data packet, the second COUNT is determined based on the third air interface time and the third HFN corresponding to the third air interface time according to a preset rule, and the third data packet is generated according to the second COUNT, and then a message containing new DCI and the third data packet is sent to the terminal at the third air interface time, wherein the RV field in the new DCI is set to 0 according to the protocol.

[0252] Since the DCI is the initial transmission DCI, after the terminal receives the DCI at the third air interface time, the terminal takes the third air interface time as the air interface time for constituting the COUNT corresponding to the DCI, takes the third HFN corresponding to the third air interface time as the HFN for constituting the COUNT corresponding to the DCI, obtains the COUNT (second COUNT) corresponding to the DCI, and after performing integrity check on the DCI according to the second COUNT, receives the third data packet at the third air interface time according to the indication of the DCI. Since the DCI indicates that the RV corresponding to the third data packet is RV0, the terminal determines the COUNT (second COUNT) corresponding to the third data packet based on the third air interface time and the third HFN according to a preset rule, and performs integrity check and / or decryption on the third data packet according to the second COUNT.

[0253] In addition, after the second communication device receives the third data packet, since the COUNT (second COUNT) corresponding to the third data packet is different from the COUNT (first COUNT) corresponding to the first data packet, the second communication device directly processes the third data packet as an initial transmission data packet and does not perform soft combining with the first data packet. Moreover, in the case where no retransmission data packet generated by using the same COUNT as the first data packet is received after a certain time interval, the first data packet is discarded.

[0254] The above scheme is described by taking the first communication device as a base station and the second communication device as a terminal as an example. In the case where the first communication device is a terminal and the second communication device is a base station, the base station can directly enter the DTX mode and send a new DCI with the RV field set to 0 to the terminal in the case where the base station does not receive an ACK or NACK from the terminal after sending the DCI scheduling the first data packet, and instruct the terminal to retransmit the information corresponding to the first data packet according to a third air interface time indicated by the new DCI. For specific implementation manners, reference can be made to related descriptions in the above embodiments, and details are not described herein again.

[0255] Based on the scheme, in the process of retransmitting the information corresponding to the first data packet by the first communication device and the second communication device, in the case where the third scheduling information indicates that the RV of the third data packet is RV0, the safety protection of the third data packet is implemented according to the air interface time (the third air interface time) corresponding to the third data packet. Even if the scheduling information is lost in the process of transmitting the first data packet, the first communication device and the second communication device can determine the COUNT used for implementing the safety protection of the third data packet according to the third air interface time according to the indication of the third scheduling information, so that the understanding of the COUNT corresponding to the third data packet by the first communication device and the second communication device is consistent, and the reliability of data transmission is improved.

[0256] In a possible implementation, the first communication device sends or receives third indication information. Correspondingly, the second communication device receives or sends the third indication information. The third indication information indicates an initial value of the HFN.

[0257] The manner in which the first communication device and the second communication device interact with the third indication information is similar to the manner in which the first communication device and the second communication device interact with the first indication information in the foregoing embodiments. For details, reference can be made to related descriptions in the foregoing embodiments, and details are not described herein again.

[0258] That is, the initial value of the HFN is indicated by the base station for the terminal. The initial value of the HFN can be understood as the current HFN maintained by the base station when the base station sends the third indication information.

[0259] For example, the third indication information can be carried in a predefined field in signaling for implementing random access, or can be carried in a predefined field in signaling for implementing security mode negotiation after random access, or can be carried in predefined signaling. The predefined can be understood as predefined by a protocol, or can be understood as agreed by the first communication device and the second communication device in advance.

[0260] As a possible implementation, the first communication device and the second communication device maintain the HFN according to the air interface time.

[0261] For example, in the case of FN rollover in air interface time, the value of HFN is incremented by one.

[0262] For example, in the case of FN rollover in air interface time, the value of HFN is incremented by one.

[0263] For example, in the case of FN rollover in air interface time, the value of HFN is incremented by one.

[0264] Based on the scheme, since the first communication device and the second communication device are synchronized in air interface time, in the case that the first communication device and the second communication device maintain the value of HFN according to the HFN initial value indicated by the third indication information and the air interface time, the understanding of the first communication device and the second communication device on the HFN corresponding to each air interface time is the same, and thus the understanding of the first communication device and the second communication device on the COUNT corresponding to different air interface times is also the same, thereby improving the reliability of security protection of the full protocol stack data packet based on COUNT.

[0265] In a possible implementation, the first communication device is a terminal, and the second communication device is a base station. The first communication device receives the MIB from the second communication device, and updates the maintained air interface time according to the MIB. The MIB includes fourth indication information, and the fourth indication information indicates the current FN.

[0266] For example, the fourth indication information is carried in the FN field in the MIB, or the fourth indication information is carried in a predefined field in the MIB. The predefined field can be predefined by a protocol or agreed by the first communication device and the second communication device in advance.

[0267] That is, after the terminal receives the MIB issued by the base station, the air interface time corresponding to the FN (current FN) carried in the MIB is used to update the air interface time maintained by the terminal, and the air interface time maintained by the terminal is updated to the air interface time corresponding to the current FN.

[0268] Based on the scheme, the first communication device can check and correct the air interface time maintained by the first communication device based on the periodically broadcasted MIB, reduce the possibility of air interface time asynchronization between the first communication device and the second communication device, and improve the reliability of data packet security protection according to the air interface time.

[0269] In a possible implementation, the first communication device is a base station, and the second communication device is a terminal. The second communication device receives the MIB from the first communication device, and updates the maintained air interface time according to the MIB. The MIB includes fourth indication information, and the fourth indication information indicates the current FN.

[0270] The manner in which the second communication device updates the air interface time according to the MIB is similar to the manner in which the first communication device updates the air interface time according to the MIB, and details can be referred to the foregoing embodiments.

[0271] Taking the first communication device as a base station and the second communication device as a terminal as an example, the process in which the first communication device and the second communication device maintain the air interface time and the HFN can refer to FIG. 17, and includes the following steps.

[0272] S1701. The base station broadcasts the MIB. Correspondingly, the terminal receives the MIB from the base station. The MIB includes the current FN of the base station.

[0273] For example, the base station periodically broadcasts the synchronization signal and the physical broadcast channel block (SSB) and the MIB according to the broadcast interval specified in the protocol. After receiving the SSB, the terminal parses the system information carried in the MIB according to the SSB, and obtains the current FN of the base station.

[0274] S1702. The terminal and the base station implement air interface time synchronization.

[0275] For example, after obtaining the current FN of the base station, the terminal determines the SFN and the slot number corresponding to the FN by means of synchronization point calculation, so as to obtain the current air interface time of the base station. Then, the terminal sets the air interface time maintained by the terminal to the current air interface time of the base station, so as to implement air interface time synchronization with the base station.

[0276] Further, after the base station and the terminal implement air interface time synchronization, the base station and the terminal can respectively maintain the air interface time according to the time length of one slot. After each slot, the slot number is incremented by 1. In the case of slot number rollover, the SFN is incremented by 1. In the case of SFN rollover, the FN is incremented by 1.

[0277] As a possible implementation, after the terminal and the base station implement stable time synchronization, the terminal can start an automatic timer and set the timing length of the automatic timer to the time length of one slot. After each slot, the air interface time maintained by the terminal is updated.

[0278] Based on the scheme, in the case of short-time disconnection of the terminal, the understanding of the terminal and the base station on the air interface time can still be consistent, and the probability of inconsistent understanding of the terminal and the base station on the air interface time is reduced.

[0279] S1703, the terminal and the base station implement uplink synchronization.

[0280] For example, the terminal performs random access through a random access process to implement uplink synchronization with the base station.

[0281] S1704, the base station sends the initial value of the HFN. Correspondingly, the terminal receives the initial value of the HFN.

[0282] For example, the base station carries the initial value of the HFN in the initial HFN field in the AS Security Mode signaling in the process of security mode negotiation (AS Security Mode) with the terminal. After receiving the AS Security Mode signaling, the terminal obtains the initial value of the HFN according to the analysis result of the initial HFN field.

[0283] The initial HFN field can be pre-defined by the protocol or pre-agreed by the base station and the terminal.

[0284] S1705, the terminal and the base station maintain the HFN according to the air interface time.

[0285] For example, in the process of maintaining the HFN according to the air interface time, the value of the FN can be detected, and in the case of FN rollover, the value of the HFN is updated from the current value (such as the initial value) to the current value plus 1, or in the case that the number of changes of the value of the FN is greater than a preset value, the value of the HFN is updated from the current value to the current value plus 1.

[0286] S1706, the terminal corrects the air interface time and the HFN according to the MIB.

[0287] In the case of short-time disconnection of the terminal, the terminal cannot obtain the air interface signal sent by the base station for a short time. Since the terminal may deviate in the process of maintaining the air interface time and the HFN by itself, the terminal can update the air interface time and the HFN maintained by the terminal according to the MIB message in the case of receiving the MIB message sent by the base station.

[0288] As a possible implementation, in the case that the terminal is stably connected with the base station, the terminal periodically acquires the MIB message broadcast by the base station, and after receiving the MIB message, calculates the current air interface time of the base station according to the MIB message, and updates the air interface time maintained by the terminal according to the current air interface time of the base station. Then, the maintained HFN is checked according to the updated air interface time, and the HFN maintained by the terminal is corrected in the case that the HFN has a deviation.

[0289] As another possible implementation, after the terminal is temporarily disconnected and reconnected, after receiving the MIB message from the base station, the current air interface time of the base station can be recalculated according to the FN in the MIB message, and the counting result of the automatic timer and the air interface time maintained by the terminal are updated according to the calculated current air interface time of the base station. Then, the maintained HFN is checked according to the updated air interface time, and the HFN maintained by the terminal is corrected in the case that the HFN has a deviation.

[0290] Based on the above scheme, in the process of the first communication device and the second communication device interacting with the data packet (first data packet) of the lower layer of the PDCP layer, the first communication device can perform integrity protection and / or encryption on the first data packet based on the first COUNT, and the second communication device performs integrity check and / or decryption on the first data packet based on the first COUNT, thereby realizing security protection of the data packet of the lower layer of the PDCP layer, and reducing the risk of forgery and tampering of the lower layer data / signaling of the PDCP layer; the first COUNT is determined according to the first HFN and the first air interface time corresponding to the first data packet, and the first HFN is the HFN corresponding to the first air interface time, that is, the determination of the first COUNT mainly depends on the air interface time corresponding to the first data packet. Since the first communication device and the second communication device performing air interface communication through the wireless protocol stack will keep the air interface time synchronized, in the case of interacting with the first data packet, the first air interface time can be determined based on the air interface time of transmitting the first data packet or the scheduling information of scheduling the first data packet, without the need to carry indication information for determining the first COUNT in the first data packet, which is conducive to realizing security protection of the first data packet without increasing air interface overhead or increasing a small amount of air interface overhead.

[0291] The above describes the method provided by the present application, and in addition, the present application also provides a communication device for implementing the functions described in the above method embodiments.

[0292] It should be understood that, in order to achieve the above functions, the communication device comprises hardware structures and / or software modules corresponding to the functions. Those skilled in the art should easily understand that, in combination with the embodiments disclosed in the present document, the units and algorithm steps of the examples described above can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is implemented in the form of hardware or computer software driving hardware depends on a specific application and design constraint condition of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but the implementation should not be considered beyond the scope of the present application.

[0293] The embodiments of the present application can divide the functions of the communication device according to the above-mentioned method embodiments, for example, each function module can be divided according to each function, or two or more functions can be integrated into one processing module. The integrated module can be implemented in the form of hardware or software function module. It should be noted that the division of the modules in the embodiments of the present application is illustrative, and is only a logical function division. Actual implementation can have another division method.

[0294] FIG. 18 shows a structural schematic diagram of a communication device 180. The communication device 180 comprises a processing module 1801 and a transceiver module 1802. The communication device 180 can be used to implement the functions of the first communication device or the second communication device.

[0295] In some embodiments, the communication device 180 can further comprise a storage module (not shown in FIG. 18) for storing program instructions and data.

[0296] In some embodiments, the transceiver module 1802, which can also be referred to as a transceiver unit, is used to implement the sending and / or receiving functions. The transceiver module 1802 can be composed of a transceiver circuit, a transceiver, a transceiver or a communication interface.

[0297] In some embodiments, the transceiver module 1802 can include a receiving module and a sending module, which are respectively used to perform the receiving and sending steps of the first communication device or the second communication device in the above-mentioned method embodiments, and / or are used to support other processes of the technologies described herein; the processing module 1801 can be used to perform the processing steps of the first communication device or the second communication device in the above-mentioned method embodiments, and / or is used to support other processes of the technologies described herein.

[0298] When the communication device 180 is used to implement the functions of the first communication device, in one possible implementation, the transceiver module 1802 is used to send or receive the first scheduling information, the first scheduling information is used to schedule the first data packet, and the first scheduling information indicates the first air interface time.

[0299] In a possible implementation, the transceiver 1802 is configured to send or receive first indication information, the first indication information indicating that a redundancy version RV corresponding to the first data packet is RV0.

[0300] In a possible implementation, the transceiver 1802 is configured to send, to the second communication apparatus, a second data packet, the second data packet being a retransmission data packet of the first data packet, and the second data packet being a data packet that is integrity protected and / or encrypted according to the first COUNT.

[0301] In a possible implementation, the transceiver 1802 is configured to send or receive second scheduling information, the second scheduling information being used for scheduling the second data packet, and the second scheduling information indicating a second air interface time; and receive or send second indication information, the second indication information indicating a first offset and / or a second offset, the first offset being an offset between the first air interface time and the second air interface time, and the second offset being an offset between the first HFN and a second HFN, the second HFN being an HFN corresponding to the second air interface time.

[0302] In a possible implementation, the processing module 1801 is configured to generate a third data packet according to a second COUNT, the third data packet being a retransmission data packet of the first data packet; and the transceiver 1802 is configured to send, to the second communication apparatus, the third data packet. The second COUNT is determined according to a third HFN and a third air interface time corresponding to the third data packet, and the third HFN is an HFN corresponding to the third air interface time.

[0303] In a possible implementation, the transceiver 1802 is configured to send or receive third scheduling information, the third scheduling information being used for scheduling the third data packet, and the third scheduling information indicating a third air interface time and that a redundancy version RV corresponding to the third data packet is RV0.

[0304] In a possible implementation, the transceiver 1802 is configured to send or receive third indication information, the third indication information indicating an initial value of a superframe number; and the processing module 1801 is configured to, in a case where a frame number FN in the air interface time rolls over, add 1 to the superframe number.

[0305] In a possible implementation, the transceiver 1802 is configured to receive a master information block MIB, the MIB including fourth indication information, the fourth indication information indicating a current FN; and the processing module 1801 is configured to determine the air interface time according to the current FN.

[0306] In the case where the communication apparatus 180 is configured to implement functions of the second communication apparatus, in a possible implementation, the transceiver 1802 is configured to receive or send first scheduling information, the first scheduling information being used for scheduling the first data packet, and the first scheduling information indicating a first air interface time.

[0307] In a possible implementation, the transceiver 1802 is configured to receive or send first indication information, where the first indication information indicates that a redundancy version RV corresponding to the first data packet is RV0.

[0308] In a possible implementation, the transceiver 1802 is configured to receive, from the first communication apparatus, a second data packet, where the second data packet is a retransmission data packet of the first data packet; and the processing module 1801 is configured to perform integrity check on the second data packet according to the first COUNT, and / or perform decryption on the second data packet according to the first COUNT.

[0309] In a possible implementation, the transceiver 1802 is configured to receive or send second scheduling information, where the second scheduling information is used for scheduling the second data packet, and the second scheduling information indicates a second air interface time; and the transceiver 1802 is configured to receive or send second indication information, where the second indication information indicates the first offset and / or the second offset, the first offset is an offset between the first air interface time and the second air interface time, and the second offset is an offset between the first HFN and a second HFN, and the second HFN is an HFN corresponding to the second air interface time.

[0310] In a possible implementation, the transceiver 1802 is configured to receive, from the first communication apparatus, a third data packet, where the third data packet is a retransmission data packet of the first data packet; and the processing module 1801 is configured to perform integrity check on the third data packet according to a second COUNT, and / or perform decryption on the third data packet according to the second COUNT, where the second COUNT is determined according to a third HFN and a third air interface time corresponding to the third data packet, and the third HFN is an HFN corresponding to the third air interface time.

[0311] In a possible implementation, the transceiver 1802 is configured to receive or send third scheduling information, where the third scheduling information is used for scheduling the third data packet, and the third scheduling information indicates a third air interface time and that a redundancy version RV corresponding to the third data packet is RV0.

[0312] In a possible implementation, the transceiver 1802 is configured to receive or send third indication information, where the third indication information indicates an initial value of a superframe number; and the processing module 1801 is configured to add 1 to the superframe number in a case where a frame number FN in the air interface time rolls over.

[0313] In a possible implementation, the transceiver 1802 is configured to receive a system information block MIB, where the MIB includes fourth indication information, and the fourth indication information indicates a current FN; and the processing module 1801 is configured to determine the air interface time according to the current FN.

[0314] All related content of each step involved in the method embodiments described above can be cited to the function description of the corresponding function module, which will not be repeated here.

[0315] In the present application, the communication apparatus 180 can be presented in the form of integrated division of various functional modules. The "module" here can refer to a specific application-specific integrated circuit (ASIC), a circuit, a processor and a memory executing one or more software or firmware programs, an integrated logic circuit, and / or other devices that can provide the above functions.

[0316] In some embodiments, when the communication apparatus 180 in FIG. 18 is a chip or a chip system, the functions / implementation processes of the transceiver module 1802 can be implemented through the input / output interface (or the communication interface) of the chip or the chip system, and the functions / implementation processes of the processing module 1801 can be implemented through the processor (or the processing circuit) of the chip or the chip system.

[0317] Since the communication apparatus 180 provided by the present embodiment can execute the above method, the technical effects that can be obtained thereby can refer to the above method embodiments, which will not be described here again.

[0318] As a possible product form, the first communication apparatus or the second communication apparatus described in the embodiments of the present application can be implemented using one or more field programmable gate arrays (FPGAs), programmable logic devices (PLDs), controllers, state machines, gate logic, discrete hardware components, any other suitable circuits, or any combination of circuits capable of performing the various functions described throughout the present application.

[0319] As another possible product form, the first communication apparatus or the second communication apparatus described in the embodiments of the present application can be implemented by a general bus architecture. For ease of illustration, refer to FIG. 19, which is a structural schematic diagram of a communication apparatus 1900 provided by the embodiments of the present application, the communication apparatus 1900 including a processor 1901 and a transceiver 1902. The communication apparatus 1900 can be a first communication apparatus, or a chip or a chip system therein; or the communication apparatus 1900 can be a second communication apparatus, or a chip or a module therein. FIG. 19 only shows the main components of the communication apparatus 1900. In addition to the processor 1901 and the transceiver 1902, the communication apparatus can further include a memory 1903, and an input / output device (not shown in the figure).

[0320] Optionally, the processor 1901 is mainly used for processing communication protocol and communication data, and controlling the whole communication device, executing software program, processing data of the software program, so as to realize the method provided in the above method embodiments. The memory 1903 is mainly used for storing software program and data. The transceiver 1902 can include radio frequency circuit and antenna, the radio frequency circuit is mainly used for conversion between baseband signal and radio frequency signal and processing of the radio frequency signal. The antenna is mainly used for receiving and transmitting radio frequency signal in the form of electromagnetic wave. The input and output device, such as touch screen, display screen, keyboard and the like, is mainly used for receiving user input data and outputting data to the user.

[0321] Optionally, the processor 1901, the transceiver 1902 and the memory 1903 can be connected through a communication bus.

[0322] When the communication device is powered on, the processor 1901 can read the software program in the memory 1903, interpret and execute the instructions of the software program, and process the data of the software program. When it is necessary to send data wirelessly, the processor 1901 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 in the form of electromagnetic wave through the antenna. When data is sent to the communication 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 1901. The processor 1901 converts the baseband signal into data and processes the data.

[0323] In another implementation, the radio frequency circuit and the antenna can be arranged independently of the processor performing baseband processing, for example, in a distributed scenario, the radio frequency circuit and the antenna can be arranged remotely from the communication device.

[0324] In some embodiments, in hardware implementation, those skilled in the art can conceive that the above-mentioned communication device 180 can adopt the form of the communication device 1900 shown in FIG. 19.

[0325] As an example, the function / implementation process of the processing module 1801 in FIG. 18 can be realized by the processor 1901 in the communication device 1900 shown in FIG. 19 calling computer execution instructions stored in the memory 1903. The function / implementation process of the transceiving module 1802 in FIG. 18 can be realized by the transceiver 1902 in the communication device 1900 shown in FIG. 19.

[0326] As another possible product form, the first communication apparatus or the second communication apparatus in this application can adopt the component structure shown in FIG. 20, or include the components shown in FIG. 20. FIG. 20 is a component diagram of a communication apparatus 2000 provided in this application, which can be the first communication apparatus or a chip or system on chip in the first communication apparatus; or can be the second communication apparatus or a module or chip or system on chip in the second communication apparatus.

[0327] As shown in FIG. 20, the communication apparatus 2000 includes at least one processor 2001, and at least one communication interface (only one communication interface 2004 is shown in FIG. 20 for example, and the processor 2001 is taken as an example for description). Optionally, the communication apparatus 2000 can further include a communication bus 2002 and a memory 2003.

[0328] The processor 2001 can be a general central processing unit (CPU), a general processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a PLD, or any combination thereof. The processor 2001 can also be other apparatuses with processing functions, such as a circuit, a device, or a software module, without limitation.

[0329] The communication bus 2002 is used to connect different components in the communication apparatus 2000, so that different components can communicate. The communication bus 2002 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in FIG. 20, but it does not mean that there is only one bus or only one type of bus.

[0330] The communication interface 2004 is used to communicate with other devices or communication networks. For example, the communication interface 2004 can be a module, a circuit, a transceiver, or any apparatus capable of realizing communication. Optionally, the communication interface 2004 can also be an input / output interface in the processor 2001, used to realize signal input and signal output of the processor.

[0331] The memory 2003 can be an apparatus with a storage function, used to store instructions and / or data. The instructions can be a computer program.

[0332] Exemplarily, the memory 2003 can be a read-only memory (ROM) or other type of static storage device that can store static information and / or instructions that are not to be changed by the processor 2001; or can be a random access memory (RAM), or other type of dynamic storage device that can store information and / or instructions that are to be changed by the processor 2001. The memory 2003 can also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, an optical disk storage including a compact disc, a laser disc, an optical disc, a digital versatile disc, a Blu-ray disc, and the like, a magnetic disk storage or other magnetic storage devices, or the like, without limitation.

[0333] It should be noted that the memory 2003 can exist independently of the processor 2001, or can be integrated with the processor 2001. The memory 2003 can be located within the communication apparatus 2000, or can be located outside the communication apparatus 2000, without limitation. The processor 2001 can be used to execute instructions stored in the memory 2003 to implement the method provided by the embodiments described below.

[0334] As an optional implementation, the communication apparatus 2000 can further include an output device 2005 and an input device 2006. The output device 2005 communicates with the processor 2001, and can display information in various ways. For example, the output device 2005 can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device 2006 communicates with the processor 2001, and can receive user input in various ways. For example, the input device 2006 can be a mouse, a keyboard, a touch screen device, a sensor device, etc.

[0335] In some embodiments, in a hardware implementation, those skilled in the art can conceive that the communication apparatus 180 shown in FIG. 18 can take the form of the communication apparatus 2000 shown in FIG. 20.

[0336] As an example, the function / implementation process of the processing module 1801 in FIG. 18 can be implemented by invoking the computer-executable instructions stored in the memory 2003 by the processor 2001 in the communication apparatus 2000 shown in FIG. 20. The function / implementation process of the transceiving module 1802 in FIG. 18 can be implemented by the communication interface 2004 in the communication apparatus 2000 shown in FIG. 20.

[0337] It should be noted that the structure shown in FIG. 20 does not constitute a specific limitation on the first communication apparatus or the second communication apparatus. For example, in some other embodiments of the present application, the first communication apparatus or the second communication apparatus can include more or fewer components than those shown, or combine certain components, or split certain components, or different arrangement of components. The components shown can be implemented in hardware, software, or a combination of software and hardware.

[0338] In some embodiments, the embodiments of the present application further provide a communication apparatus, which includes a processor configured to implement the method in any of the method embodiments.

[0339] As a possible implementation, the communication apparatus further includes a memory. The memory is configured to store necessary computer programs and data. The computer programs can include instructions, and the processor can invoke the instructions in the computer programs stored in the memory to instruct the communication apparatus to perform the method in any of the method embodiments. Of course, the memory can also not be in the communication apparatus.

[0340] As another possible implementation, the communication apparatus further includes an interface circuit, which is a code / data reading / writing interface circuit, and is configured to receive computer-executable instructions (stored in the memory, possibly directly from the memory, or possibly through other devices) and transmit them to the processor.

[0341] As yet another possible implementation, the communication apparatus further includes a communication interface configured to communicate with modules outside the communication apparatus.

[0342] It can be understood that the communication apparatus can be a chip or a chip system. When the communication apparatus is a chip system, it can be composed of a chip or include a chip and other discrete devices, and the embodiments of the present application do not make a specific limitation thereon.

[0343] The present application further provides a computer-readable storage medium, which stores a computer program or instructions, and the computer program or instructions are executed by a computer to implement the functions of any of the method embodiments.

[0344] The present application further provides a computer program product, which is executed by a computer to implement the functions of any of the method embodiments.

[0345] Those skilled in the art can understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0346] It can be understood that the system, device and method described in the present application can also be implemented in other manners. For example, the device embodiments described above are merely schematic; for example, the division of the units is only a logical function division, and there can be another division manner in actual implementation; for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between the units can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0347] The units described as separate components can or can not be physically separate, i.e., can be located in one place, or can be distributed on a plurality of network units. The components shown as units can or can not be physical units. Part or all of the units can be selected according to actual needs to achieve the purposes of the embodiments.

[0348] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be a physically independent unit, or two or more units can be integrated into one unit.

[0349] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive (SSD)). In this embodiment, the computer may include the aforementioned apparatus.

[0350] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0351] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the scope of this application. Accordingly, this specification and drawings are merely illustrative descriptions of the application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of the claims and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A communication method characterized by comprising: The method comprises: receiving a first data packet from a first communication device, the first data packet being a data packet at a lower layer of a packet data convergence protocol (PDCP) layer; performing integrity check on the first data packet according to a first COUNT, and / or performing decryption on the first data packet according to the first COUNT, the first COUNT being determined according to a first hyper frame number (HFN) and a first air interface time corresponding to the first data packet, the first HFN being an HFN corresponding to the first air interface time.

2. The method of claim 1, wherein, The method further comprises: receiving or sending first scheduling information, the first scheduling information being used for scheduling the first data packet, the first scheduling information indicating the first air interface time.

3. The method of claim 2, wherein, The method further comprises: receiving or sending first indication information, the first indication information indicating that a redundancy version (RV) corresponding to the first data packet is RV0.

4. The method according to any one of claims 1 to 3, characterized in that, The method further comprises: receiving a second data packet from the first communication device, the second data packet being a retransmission data packet of the first data packet; performing integrity check on the second data packet according to the first COUNT, and / or performing decryption on the second data packet according to the first COUNT.

5. The method of claim 4, wherein, The method further comprises: receiving or sending second scheduling information, the second scheduling information being used for scheduling the second data packet, the second scheduling information indicating a second air interface time; receiving or sending second indication information, the second indication information indicating a first offset and / or a second offset, the first offset being an offset between the first air interface time and the second air interface time, the second offset being an offset between the first HFN and a second HFN, the second HFN being an HFN corresponding to the second air interface time.

6. The method according to any one of claims 1 to 3, characterized in that, The method further comprises: receiving a third data packet from the first communication device, the third data packet being a retransmission data packet of the first data packet; performing integrity check on the third data packet according to a second COUNT, and / or performing decryption on the third data packet according to the second COUNT, the second COUNT being determined according to a third HFN and a third air interface time corresponding to the third data packet, the third HFN being an HFN corresponding to the third air interface time.

7. The method of claim 6, wherein, The method further comprises: receiving or sending third scheduling information, the third scheduling information being used for scheduling the third data packet, the third scheduling information indicating the third air interface time and that a RV corresponding to the third data packet is RV0.

8. The method according to any one of claims 1 to 7, characterized in that, The air interface time comprises at least one of the following: a frame number (FN), a subframe number (SFN) or a time slot number.

9. The method according to any one of claims 1 to 8, characterized in that, The method further comprises: receiving or sending third indication information, the third indication information indicating an initial value of a hyper frame number (HFN); in a case where a frame number (FN) in the air interface time rolls over, adding 1 to the HFN.

10. The method of claim 9, wherein, The method further comprises: receiving a system information block (SIB), the SIB comprising fourth indication information, the fourth indication information indicating a current FN; determining the air interface time according to the current FN.

11. A communication method, comprising: The method comprises: The first COUNT is determined according to a first hyper frame number (HFN) and a first air interface time corresponding to the first data packet, and the first HFN is an HFN corresponding to the first air interface time. The first data packet is transmitted to a second communication device. The first COUNT is determined according to a first hyper frame number (HFN) and a first air interface time corresponding to the first data packet, and the first HFN is an HFN corresponding to the first air interface time.

12. The method of claim 11, wherein, The method further includes: transmitting or receiving first scheduling information, the first scheduling information being used for scheduling the first data packet, and the first scheduling information indicating the first air interface time.

13. The method of claim 12, wherein, The method further includes: transmitting or receiving first indication information, the first indication information indicating that a redundancy version (RV) corresponding to the first data packet is RV0.

14. The method according to any one of claims 11 to 13, characterized in that, The method further includes: The second data packet is transmitted to a second communication device, the second data packet being a retransmission data packet of the first data packet, and the second data packet being a data packet that is integrity protected and / or encrypted according to the first COUNT.

15. The method of claim 14, wherein, The method further includes: The second scheduling information is transmitted or received, the second scheduling information being used for scheduling the second data packet, and the second scheduling information indicating a second air interface time. The second indication information is received or transmitted, the second indication information indicating a first offset and / or a second offset, the first offset being an offset between the first air interface time and the second air interface time, and the second offset being an offset between the first HFN and a second HFN, the second HFN being an HFN corresponding to the second air interface time.

16. The method of any one of claims 11-13, wherein, The method further includes: The third data packet is generated according to a second COUNT, the third data packet being a retransmission data packet of the first data packet; The third data packet is transmitted to the second communication device. The second COUNT is determined according to a third HFN and a third air interface time corresponding to the third data packet, and the third HFN is an HFN corresponding to the third air interface time.

17. The method of claim 16, wherein, The third scheduling information is transmitted or received, the third scheduling information being used for scheduling the third data packet, and the third scheduling information indicating the third air interface time and a RV corresponding to the third data packet being RV0.

18. The method according to any one of claims 11 to 17, characterized in that, The air interface time includes at least one of the following: a frame number (FN), a subframe number (SFN), or a time slot number.

19. The method according to any one of claims 11 to 18, characterized in that, The method further includes: The third indication information is transmitted or received, the third indication information indicating an initial value of a hyper frame number (HFN). In a case where a frame number (FN) in the air interface time is flipped, the HFN is increased by 1.

20. The method of claim 19, wherein, The method further includes: A master information block (MIB) is received, the MIB including fourth indication information, the fourth indication information indicating a current FN. The air interface time is determined according to the current FN.

21. A communications device, characterized by The communication device includes a processor, and the processor is configured to run a computer program or an instruction, so that the communication device performs the method according to any one of claims 1-10, or so that the communication device performs the method according to any one of claims 11-20.

22. A communication system, characterized by The communication system comprises a first communication device and a second communication device; The first communication device is configured to perform the method according to any one of claims 1-10, and the second communication device is configured to perform the method according to any one of claims 11-20.

23. A computer-readable storage medium, characterized in that, A computer readable storage medium stores computer instructions or programs which, when run on a computer, cause the method according to any one of claims 1-10 to be performed, or cause the method according to any one of claims 11-20 to be performed.

24. A computer program product, characterised in that, The computer program product comprises computer instructions; when part or all of the computer instructions are run on a computer, cause the method according to any one of claims 1-10 to be performed, or cause the method according to any one of claims 11-20 to be performed.

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