RU2825428C2 - Method and apparatus for determining hyperframe number of packet data convergence protocol object - Google Patents

Abstract

FIELD: communication technologies.

SUBSTANCE: method of determining a hyperframe number (HFN) of a packet data convergence protocol (PDCP) object, performed by a terminal device, includes receiving indication information transmitted by a network device, wherein the indication information includes HFN information, and determination of the HFN value of the PDCP object based on the HFN information. Determining the HFN value of the PDCP object based on the HFN information includes determining the HFN value of the PDCP object based on the HFN information when the applicable condition for the HFN information is satisfied.

EFFECT: high reliability of data transmission and reduced power consumption caused by blind determination of the HFN hyperframe number.

19 cl, 13 dwg

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The present invention relates to the field of communication technologies, in particular to a method for determining a hyperframe number (HFN) of a packet data convergence protocol (PDCP) entity and a device for determining the HFN number of a PDCP protocol entity.

LEVEL OF TECHNOLOGY

[0002] In a communication system, a network device continuously sends data. Therefore, the HFN value used by the network device is constantly increased. When a new terminal device joins the network to receive data sent by the network device, the terminal device does not know the HFN value used by the network device. Therefore, the terminal device cannot use the correct counter value (COUNT) to decrypt or check the integrity of the received data, which results in a failure in data decryption or a failure in data integrity checking.

ESSENCE OF THE INVENTION

[0003] Embodiments of the present invention provide a method for determining a hyperframe number (HFN) of a packet data convergence protocol (PDCP) entity and an apparatus for determining a HFN of a PDCP entity, which can be used in the field of communication technologies.

[0004] According to a first aspect, embodiments of the present invention provide a method for determining an HFN number of a PDCP protocol entity that is performed by a terminal device. The method includes: receiving indication information transmitted by a network device, wherein the indication information comprises HFN information; and determining an HFN value of the PDCP entity based on the HFN information.

[0005] In the present invention, the terminal device first receives indication information transmitted by the network device, and then determines the HFN value of the PDCP protocol entity based on the HFN information included in the indication information. In this way, the terminal device that interprets the HFN value in the same way as the network device can avoid a failure in data decryption or a failure in data integrity checking and improve the reliability of data transmission.

[0006] In some embodiments, the HFN information includes any one of the HFN values or a counter value (COUNT).

[0007] In some embodiments, determining an HFN value of a PDCP protocol entity based on the HFN information includes: determining an HFN value of the PDCP protocol entity based on the HFN information when an applicable information condition for the HFN information is met.

[0008] In some embodiments, the method further includes:

[0009] receiving an applicable condition for HFN information transmitted by a network device;

[0010] or

[0011] determination of the applicable condition for HFN information based on the adopted agreement.

[0012] In some embodiments, the applicable condition for the HFN information includes any one of a Sequence Number (SN) value or a System Frame Number (SFN) value.

[0013] In some embodiments, the SN value includes any one of the following values:

[0014] minimum SN value;

[0015] maximum SN value;

[0016] minimum SN value and maximum SN value;

[0017] section number corresponding to the SN value; or

[0018] a pair of parameters (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[0019] In some embodiments, the SFN value includes any one of the following values:

[0020] minimum SFN value;

[0021] maximum SFN value;

[0022] minimum SFN value and maximum SFN value;

[0023] section number corresponding to the SFN value; or

[0024] a pair of parameters (i, j) corresponding to an SFN value, where i denotes the number of sections after uniformly dividing all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[0025] In some embodiments, an applicable condition that must be met includes:

[0026] an SN value corresponding to a PDCP protocol data packet received by the terminal device and satisfying the applicable condition;

[0027] or

[0028] the SFN value corresponding to the PDCP protocol data packet received by the terminal device and satisfying the applicable condition.

[0029] In some embodiments, the indication information further includes information about a Multicast Broadcast Service (MBS), and the received PDCP data packet is the first PDCP data packet received by the terminal device over an MBS Radio Bearer (MRB) corresponding to the MBS service information.

[0030] In some embodiments, the SFN value corresponding to the received PDCP data packet includes any one of the following values:

[0031] an SFN value corresponding to the time position of the last physical data channel in which a PCDP protocol data packet was successfully received;

[0032] an SFN value corresponding to the time position of the first physical data channel in which a PCDP protocol data packet has been successfully received;

[0033] SFN value corresponding to successful reception of a PDCP protocol data packet.

[0034] In some embodiments, the applicable condition is an SN value, and determining the HFN value of the PDCP protocol entity based on the HFN information includes:

[0035] in case of non-fulfillment of the applicable condition and the difference s between the SN value corresponding to the PDCP protocol data packet received by the terminal device and the SN value corresponding to the applicable condition, generating updated HFN information by updating the HFN information based on the difference s; and

[0036] determining the HFN value of the PDCP protocol entity based on the updated HFN information.

[0037] In some embodiments, the applicable condition is an SFN value, and determining the HFN value of the PDCP protocol entity based on the HFN information includes:

[0038] in case of non-fulfillment of the applicable condition and the difference k between the SFN value corresponding to the PDCP protocol data packet received by the terminal device and the SFN value corresponding to the applicable condition, generating updated HFN information by updating the HFN information based on the difference k; and

[0039] determining the HFN value of the PDCP protocol entity based on the updated HFN information.

[0040] In some embodiments, the indication information further includes an HFN number update mode, and determining the HFN value of the PDCP protocol entity based on the HFN information includes:

[0041] if the applicable condition is not met, generating updated HFN information by updating the HFN information depending on the update mode; and

[0042] determining the HFN value of the PDCP protocol entity based on the updated HFN information.

[0043] In some embodiments, the update mode includes an update step size and an update direction.

[0044] In some embodiments, receiving indication information transmitted by a network device includes:

[0045] receiving indication information transmitted by a network device based on a system message;

[0046] or

[0047] receiving indication information transmitted by a network device based on a message in an MBS control channel;

[0048] or

[0049] receiving indication information transmitted by a network device based on a separate configuration message of a terminal device.

[0050] In some embodiments, the indication information further includes information about the MBS service, and determining the HFN value of the PDCP protocol entity based on the HFN information includes:

[0051] determining the HFN value of the PDCP protocol entity corresponding to the MBS service information based on the HFN information.

[0052] In some embodiments, the MBS service information includes at least one of the following types of information: an MBS service identifier (ID), an MBS channel identifier, or MBS channel protocol entity configuration information.

[0053] In some embodiments, the method includes: decrypting or checking the integrity of received data corresponding to the MBS service information based on the HFN information.

[0054] In some embodiments, determining the HFN value of the PDCP protocol entity based on the HFN information includes: determining the HFN value of the PDCP protocol entity based on the HFN information if the terminal device starts accessing the MBS service.

[0055] According to a second aspect, embodiments of the present invention provide another method for determining an HFN number of a PDCP protocol entity that is performed by a network device. The method includes: transmitting indication information to a terminal device, wherein the indication information includes HFN information.

[0056] In some embodiments, the HFN information includes any one of the HFN values or a counter value (COUNT).

[0057] In some embodiments, the indication information further includes an applicable condition for the HFN information.

[0058] In some embodiments, the applicable condition for the HFN information includes any one of a sequence number (SN) value or a system frame number (SFN) value.

[0059] In some embodiments, the SN value includes any one of the following values:

[0060] minimum SN value;

[0061] maximum SN value;

[0062] minimum SN value and maximum SN value;

[0063] the section number corresponding to the SN value; or

[0064] a pair of parameters (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[0065] In some embodiments, the SFN value includes any one of the following values:

[0066] minimum SFN value;

[0067] maximum SFN value;

[0068] minimum SFN value and maximum SFN value;

[0069] the section number corresponding to the SFN value; or

[0070] a pair of parameters (i, j) corresponding to an SFN value, where i denotes the number of sections after uniformly dividing all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[0071] In some embodiments, the indication information further includes information about a multicast broadcast service (MBS).

[0072] In some embodiments, the MBS service information includes at least one of the following types of information: an MBS service identifier (ID), an MBS channel identifier, or MBS channel protocol entity configuration information.

[0073] In some embodiments, the indication information further includes a mode of updating the HFN information.

[0074] In some embodiments, the update mode includes an update step size and an update direction.

[0075] In some embodiments, transmitting indication information to a terminal includes:

[0076] transmitting indication information to a terminal device based on a system message;

[0077] or

[0078] transmitting indication information to the terminal device based on a message in the MBS control channel;

[0079] or

[0080] transmitting indication information to a terminal device based on a separate configuration message of the terminal device.

[0081] In some embodiments, the method further includes:

[0082] in the event of a change in information in the system message other than the HFN information, transmitting to the terminal device the first change indication information;

[0083] or

[0084] in case of a change in information in the MBS control channel message other than the HFN information, transmitting to the terminal device a second change indication information;

[0085] According to a third aspect, embodiments of the present invention provide a communication device configured on the side of a terminal device. The communication device includes: a transceiver module configured to receive indication information transmitted by a network device, wherein the indication information comprises HFN information; and a processing module configured to determine an HFN value of a PDCP protocol entity based on the HFN information.

[0086] In some embodiments, the HFN information includes any one of the HFN values or a counter value (COUNT).

[0087] In some embodiments, the processing module is configured to determine an HFN value of the PDCP protocol entity based on the HFN information when the applicable condition for the HFN information is met.

[0088] In some embodiments, the transceiver module is configured to receive an applicable condition for HFN information transmitted by the network device;

[0089] or

[0090] the processing module is further configured to determine an applicable condition for the HFN information based on the agreement.

[0091] In some embodiments, the applicable condition for the HFN information includes any one of a sequence number (SN) value or a system frame number (SFN) value.

[0092] In some embodiments, the SN value includes any one of the following values:

[0093] minimum SN value;

[0094] maximum SN value;

[0095] minimum SN value and maximum SN value;

[0096] the section number corresponding to the SN value; or

[0097] a pair of parameters (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[0098] In some embodiments, the SFN value includes any one of the following values:

[0099] minimum SFN value;

[00100] maximum SFN value;

[00101] minimum SFN value and maximum SFN value;

[00102] the section number corresponding to the SFN value; or

[00103] a pair of parameters (i, j) corresponding to an SFN value, where i denotes the number of sections after uniformly dividing all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[00104] In some embodiments, an applicable condition that must be met includes:

[00105] the SN value corresponding to the PDCP protocol data packet received by the terminal device and satisfying the applicable condition;

[00106] or

[00107] the SFN value corresponding to the PDCP protocol data packet received by the terminal device and satisfying the applicable condition.

[00108] In some embodiments, the indication information further includes information about a Multicast Broadcast Service (MBS), and the received PDCP data packet is the first PDCP data packet received by the terminal device over an MBS Radio Bearer (MRB) corresponding to the MBS service information.

[00109] In some embodiments, the SFN value corresponding to the received PDCP data packet includes any one of the following values:

[00110] an SFN value corresponding to the time position of the last physical data channel in which a PCDP protocol data packet was successfully received;

[00111] an SFN value corresponding to the time position of the first physical data channel in which a PCDP protocol data packet is successfully received; and

[00112] SFN value corresponding to successful reception of a PDCP protocol data packet.

[00113] In some embodiments, the applicable condition is the value of the SN number, and the processing module is configured to:

[00114] in case of non-fulfillment of the applicable condition and the difference s between the SN value corresponding to the PDCP protocol data packet received by the terminal device and the SN value corresponding to the applicable condition, generate updated HFN information by updating the HFN information based on the difference s; and

[00115] determine the HFN value of the PDCP protocol entity based on the updated HFN information.

[00116] In some embodiments, the applicable condition is an SFN value, and the processing module is configured to:

[00117] in case of non-fulfillment of the applicable condition and the difference k between the SFN value corresponding to the PDCP data packet received by the terminal device and the SFN value corresponding to the applicable condition, generate updated HFN information by updating the HFN information based on the difference k; and

[00118] determine the HFN value of the PDCP protocol entity based on the updated HFN information.

[00119] In some embodiments, the indication information further includes a mode of updating the HFN information, and the processing module is configured to:

[00120] if the applicable condition is not met, generate updated HFN information by updating the HFN information depending on the update mode; and

[00121] determine the HFN value of the PDCP protocol entity based on the updated HFN information.

[00122] In some embodiments, the update mode includes an update step size and an update direction.

[00123] In some embodiments, the transceiver module is configured to:

[00124] receive indication information transmitted by a network device based on a system message;

[00125] or

[00126] receive indication information transmitted by a network device based on a message in the MBS control channel;

[00127] or

[00128] receive indication information transmitted by the network device based on a separate configuration message of the terminal device.

[00129] In some embodiments, the indication information further includes information about the MBS service, and the processing module is configured to:

[00130] determine the HFN value of the PDCP protocol entity corresponding to the MBS service information based on the HFN information.

[00131] In some embodiments, the MBS service information includes at least one of the following types of information: an MBS service identifier (ID), an MBS channel identifier, or MBS channel protocol entity configuration information.

[00132] In some embodiments, the processing module is configured to decrypt received data corresponding to the MBS service information or check its integrity based on the HFN information.

[00133] In some embodiments, the processing module is configured to:

[00134] determine the HFN value of the PDCP protocol entity based on the HFN information if the terminal device starts accessing the MBS service.

[00135] According to a fourth aspect, embodiments of the present invention provide a communication device configured on the side of a network device. The communication device includes: a transceiver module configured to transmit indication information to a terminal device, wherein the indication information includes HFN information.

[00136] In some embodiments, the HFN information includes any one of the HFN values or a counter value (COUNT).

[00137] In some embodiments, the transceiver module is configured to transmit an applicable condition for the HFN information to the terminal device.

[00138] In some embodiments, the applicable condition for the HFN information includes any one of a sequence number (SN) value or a system frame number (SFN) value.

[00139] In some embodiments, the SN value includes any one of the following values:

[00140] minimum SN value;

[00141] maximum SN value;

[00142] minimum SN value and maximum SN value;

[00143] section number corresponding to the SN value; or

[00144] a pair of parameters (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[00145] In some embodiments, the SFN value includes any one of the following values:

[00146] minimum SFN value;

[00147] maximum SFN value;

[00148] minimum SFN value and maximum SFN value;

[00149] the section number corresponding to the SFN value; or

[00150] a pair of parameters (i, j) corresponding to an SFN value, where i denotes the number of sections after uniformly dividing all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[00151] In some embodiments, the indication information further includes information about a multicast broadcast service (MBS).

[00152] In some embodiments, the MBS service information includes at least one of the following types of information: an MBS service identifier (ID), an MBS channel identifier, or MBS channel protocol entity configuration information.

[00153] In some embodiments, the indication information further includes a mode of updating the HFN information.

[00154] In some embodiments, the update mode includes an update step size and an update direction.

[00155] In some embodiments, the transceiver module is configured to:

[00156] transmit indication information to the terminal device based on the system message;

[00157] or

[00158] transmit indication information to the terminal device based on a message in the MBS control channel;

[00159] or

[00160] transmit indication information to the terminal device based on a separate configuration message of the terminal device.

[00161] In some embodiments, the transceiver module is configured to:

[00162] in case of a change in information in the system message other than the HFN information, transmit to the terminal device the first change indication information;

[00163] or

[00164] in case of a change in information in the MBS control channel message, in addition to the HFN information, transmit to the terminal device a second change indication information;

[00165] According to a fifth aspect, embodiments of the present invention provide a communication device. The communication device includes: a processor. When the processor calls the computer programs stored in the memory, the method described in the first aspect above is implemented.

[00166] According to a sixth aspect, embodiments of the present invention provide a communication device. The communication device includes: a processor. When the processor calls the computer programs stored in the memory, the method described in the above second aspect is implemented.

[00167] According to a seventh aspect, embodiments of the present invention provide a communication device. The communication device includes: a processor and a memory with computer programs stored therein. When the processor executes the computer programs stored in the memory, the communication device is caused to implement the method described in the first aspect above.

[00168] According to an eighth aspect, embodiments of the present invention provide a communication device. The communication device includes: a processor and a memory with computer programs stored therein. When the processor executes the computer programs stored in the memory, the communication device is caused to implement the method described in the above second aspect.

[00169] According to a ninth aspect, in embodiments of the present invention, a communication device is provided. The communication device includes: a processor and an interface circuit. The interface circuit is configured to receive code instructions and transmit code instructions to the processor, and the processor is configured to execute the code instructions in order to cause the communication device to implement the method described in the first aspect above.

[00170] According to a tenth aspect, in embodiments of the present invention, a communication device is provided. The communication device includes: a processor and an interface circuit. The interface circuit is configured to receive code instructions and transmit code instructions to the processor, and the processor is configured to execute the code instructions in order to cause the communication device to implement the method described in the above second aspect.

[00171] According to an eleventh aspect, in embodiments of the present invention, a communication system is provided. The system includes: a communication device according to a third aspect, or a communication device according to a fourth aspect, or a communication device according to a fifth aspect, or a communication device according to a sixth aspect, or a communication device according to a seventh aspect, or a communication device according to an eighth aspect, or a communication device according to a ninth aspect, or a communication device according to a tenth aspect.

[00172] According to a twelfth aspect, embodiments of the present invention provide a computer-readable storage medium, on which instructions used by the above-mentioned terminal device are stored. When executing the instructions, the terminal device is caused to implement the method according to the first aspect.

[00173] According to a thirteenth aspect, embodiments of the present invention provide a computer-readable storage medium that stores instructions used by the above-mentioned network device. When executing the instructions, the network device is caused to implement the method according to the second aspect.

[00174] According to a fourteenth aspect, embodiments of the present invention provide a computer program product including computer programs. When the computer executes the computer program, the computer is caused to implement the method according to the first aspect.

[00175] According to a fifteenth aspect, embodiments of the present invention provide a computer program product including computer programs. When the computer executes the computer program, the computer is caused to implement the method according to the second aspect.

[00176] According to a sixteenth aspect, embodiments of the present invention provide a chip-based system. The chip-based system includes at least one processor and an interface designed to support the operation of a terminal device in order to implement the functions associated with the first aspect, such as determining or processing at least one of the types of information or data used in the method described above. In a possible embodiment, the chip-based system further includes a memory. The memory is configured to store the necessary computer programs and data of the terminal device. The chip-based system may include several chips or may include a chip and other discrete devices.

[00177] According to the seventeenth aspect, in embodiments of the present invention, a chip-based system is proposed. The chip-based system includes at least one processor and an interface designed to support the operation of a network device in order to implement functions related to the second aspect, for example, determining or processing at least one of the types of information or data used in the method described above. In a possible embodiment, the chip-based system further includes a memory. The memory is configured to store the necessary computer programs and data of the network device. The chip-based system may include several chips or may include a chip and other discrete devices.

[00178] According to an eighteenth aspect, in embodiments of the present invention, a computer program is provided. When the computer executes the computer program, the computer is caused to implement the method according to the first aspect.

[00179] According to a nineteenth aspect, in embodiments of the present invention, a computer program is provided. When the computer executes the computer program, the computer is caused to implement the method according to the second aspect.

BRIEF DESCRIPTION OF DRAWINGS

[00180] In order to clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the following describes the drawings used in the embodiments of the invention or the prior art.

[00181] Fig. 1 is a block diagram of a communication system according to embodiments of the present invention.

[00182] Fig. 2 is a flow chart illustrating a method for determining a hyperframe number (HFN) of a packet data convergence protocol (PDCP) entity in accordance with embodiments of the present invention.

[00183] Fig. 3 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention.

[00184] Fig. 4 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention.

[00185] Fig. 5 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention.

[00186] Fig. 6 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention.

[00187] Fig. 7 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention.

[00188] Fig. 8 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention.

[00189] Fig. 9 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention.

[00190] Fig. 10 is a block diagram of a communication device according to embodiments of the present invention.

[00191] Fig. 11 is a block diagram of a communication device according to embodiments of the present invention.

[00192] Fig. 12 is a block diagram of a communication device according to embodiments of the present invention.

[00193] Fig. 13 shows a block diagram of a microcircuit according to embodiments of the present invention.

DETAILED DESCRIPTION

[00194] For ease of understanding, the terms used in the present invention are first introduced.

[00195] 1. Multimedia Broadcast and Multicast Service (MBMS) or Multicast Broadcast Service (MBS)

[00196] The MBS service is a practical technology that can improve spectrum utilization efficiency and is widely applied in communication systems. In the Radio Access Technology (RAT) of the 5G new radio system, the MBS service can be transmitted via the Physical Downlink Shared Channel (PDSCH) scheduled by the Physical Downlink Control Channel (PDCCH).

[00197] 2. Packet Data Convergence Protocol (PDCP)

[00198] The PDCP protocol is a wireless transmission protocol stack that can handle Radio Resource Control (RRC) messages and Internet Protocol (IP) packets. The PDCP protocol can perform IP header compression and decompression, transmit user data and maintain a radio channel sequence number (SN), and provide signaling transmission services, provide encryption and integrity protection of signaling, and decryption and integrity checking of signaling in the reverse direction.

[00199] 3. Encryption and Integrity Protection

[00200] The communication system may encrypt data and protect its integrity. Typically, the integrity protection function is implemented by adding a 32-bit message authentication code for integrity (MAC-I) to the end of the PDCP data packet.

[00201] Typically, an entity receiving PDCP data needs to know the COUNT value in order to decrypt encrypted data or verify its integrity.

[00202] The PDCP COUNT value may include both the HFN and the PDCP SN at the same time, occupying all 32 bits. Typically, the PDCP data packet header contains the SN information.

[00203] 4. System Frame Number (SFN)

[00204] In the communication system, time domain resources may be sequentially numbered with SFN numbers in 10 millisecond (ms) increments. One SFN frame may consist of 10 subframes, with each subframe being 1 ms in duration. The SFN number may be specified in the Master Information Block (MIB) of the Synchronous Signal Block (SSB).

[00205] In order to properly understand the method for determining the HFN number of a PDCP protocol entity according to the embodiments of the present invention, a communication system to which the embodiments of the present invention are applicable will first be described below.

[00206] Fig. 1 is a block diagram of a communication system according to embodiments of the present invention. The communication system may include, among other things, a network device and a terminal device. The number and shape of the devices shown in Fig. 1 are indicated only for example and do not limit the embodiments of the present invention, and in practice, two or more network devices and two or more terminal devices may be used. The communication system shown in Fig. 1 includes, as an example, one network device 11 and one terminal device 12.

[00207] It should be noted that the technical solutions used in the embodiments of the present invention can be applied to various communication systems, such as a Long Term Evolution (LTE) system, a 5th generation (5G) mobile communication system, a 5G New Radio (NR) system, or other future mobile communication systems.

[00208] The network device 11 in the embodiments of the present invention is an entity located on the network side and intended to transmit or receive signals. For example, the network device 11 may be an Evolved NodeB (eNB), a Transmission Reception Point (TRP), a next Generation NodeB (gNB) in the NR system, a base station in other future mobile communication systems, or an access node in a Wi-Fi wireless access system. The embodiments of the present invention are not limited to a specific technology and a specific form used for the network device. The network device according to the embodiments of the present invention may be composed of a Central Unit (CU) and a Distributed Unit (DU). The CU may also be called a control unit. The use of the CU-DU structure allows the protocol layer of a network device, such as a base station, to be distributed in such a way that some protocol layer functions are concentrated in the CU block for centralized management, and some or all of the remaining protocol layer functions are moved to the DU block, with the DU being centrally managed by the CU block.

[00209] The terminal device 12 in the embodiments of the present invention is an object located on the user side and for transmitting or receiving signals, such as a cellular telephone. The terminal device may also be called a terminal, user equipment (UE), mobile station (MS), mobile terminal (MT), or the like. The terminal device may be a car with a communication function, an intelligent car, a mobile phone, a wearable device, a tablet computer, a computer with a wireless transmitting and receiving function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device of an industrial control system, a wireless terminal device for autonomous driving, a wireless terminal device for remote medical surgery, a wireless terminal device of an intelligent network, a wireless terminal device of a transportation security system, a wireless terminal device of an intelligent city system, a wireless terminal device of an intelligent home system, and other similar devices. The embodiments of the present invention are not limited to a specific technology and a specific form used for the terminal device.

[00210] It should be understood that the communication system described in the embodiments of the present invention is intended to clearly explain the technical solutions according to the embodiments of the present invention and does not impose limitations on them. Those skilled in the art should understand that as system architectures evolve and new scenarios emerge, the technical solutions provided by the embodiments of the present invention will also be applicable to similar technical problems.

[00211] A method for determining an HFN number of a PDCP protocol entity and an apparatus for determining an HFN number of a PDCP protocol entity are described in detail below with reference to the accompanying drawings.

[00212] Fig. 2 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a terminal device. As shown in Fig. 2, the method may include, among other things, the following actions.

[00213] In step 21, indication information transmitted by the network device is received. The indication information includes HFN information.

[00214] In some embodiments, the HFN information includes one or more HFN or COUNT values.

[00215] It should be understood that the HFN value in the indication information corresponds to the PDCP protocol data packet that is currently used by the network device, or the COUNT value in the indication information corresponds to the PDCP protocol data packet that is currently transmitted by the network device.

[00216] In order to avoid a situation in which a terminal device that has just connected to receive PDCP protocol data transmitted by a network device cannot use a correct COUNT value to decrypt or check the integrity of a PDCP protocol data packet, in the present invention, the network device may, by following a certain rule, send an indication message to the terminal device to inform the terminal device of the HFN or COUNT value corresponding to the current PDCP protocol data.

[00217] In step 22, the HFN value of the PDCP protocol entity is determined based on the HFN information.

[00218] For example, an indication message received by a terminal device indicates that the HFN value is 1, and in this case, the terminal device may determine that the HFN value of the PDCP protocol entity is 1.

[00219] In another example, an indication message received by a terminal device indicates that the COUNT value is 0, in which case the terminal device may determine that the HFN value of the PDCP protocol entity is 0.

[00220] In another example, an indication message received by a terminal device indicates that the COUNT value is 8, and if the terminal device knows that the SN value is in the range from 0 to 7, and the SN value in the received PDCP protocol data packet is 7, then the terminal device can determine that the HFN value of the PDCP protocol entity is 1.

[00221] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the content of the indication information, the HFN value, the COUNT value and other similar parameters in the embodiments of the present invention.

[00222] In some examples, when the indication information received by the newly connected terminal device indicates a COUNT value, the terminal device may directly use the COUNT value to decrypt or check the integrity of data in the received data packet, calculate the HFN value that is currently used by the network device based on the COUNT value and the SN number in the received data packet, and then determine the HFN value of the PDCP protocol entity based on the calculated HFN value.

[00223] In some examples, when the indication information received by a newly connected terminal device indicates an HFN value, the terminal device may use the HFN value to determine a corresponding COUNT value and then decrypt the data or check the integrity of the data in the received data packet.

[00224] In the present invention, the terminal device may first receive indication information transmitted by the network device, and then determine the HFN value of the PDCP protocol entity based on the HFN information included in the indication information. In this way, the terminal device may interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking, and improve the reliability of data transmission.

[00225] Fig. 3 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a terminal device. As shown in Fig. 3, the method may include, among other things, the following actions.

[00226] In step 31, indication information transmitted by the network device is received. The indication information includes HFN information.

[00227] In some examples, the HFN information includes one or more HFN or COUNT values.

[00228] In step 32, when the applicable condition for the HFN information is met, the HFN value of the PDCP protocol entity is determined based on the HFN information.

[00229] In some examples, the applicable condition for HFN information includes one or more SN or SFN values.

[00230] In some examples, the applicable condition may be specified by the network device or may be determined by the terminal device in accordance with an agreement that is not limited by the present invention.

[00231] The network device may notify the applicable condition for the HFN information in the process of transmitting the HFN information to the terminal device. Or, the network device may also notify the terminal device of the applicable condition for the HFN information separately using other indication information, which is not limited by the present invention.

[00232] In some examples, the SN value may be a minimum SN value.

[00233] Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the SN value corresponding to the PDCP protocol data packet received by the terminal device is greater than or equal to the minimum SN value.

[00234] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SN value of 5, then when the terminal device determines that the SN value corresponding to the received PDCP protocol data packet is 7, and since the value 7 is greater than the minimum SN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00235] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SN value and other similar parameters in the embodiments of the present invention.

[00236] In some examples, the SN value may be a minimum SN value.

[00237] Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the SN value corresponding to the PDCP protocol data packet received by the terminal device is less than or equal to the maximum SN value.

[00238] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a maximum SN value of 5, then when the terminal device determines that the SN value corresponding to the received PDCP protocol data packet is 1, and since the value 1 is less than the maximum SN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value for the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00239] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the maximum SN value and other similar parameters in the embodiments of the present invention.

[00240] In some examples, the SN value may be both a minimum SN value and a maximum SN value.

[00241] Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the SN value corresponding to the PDCP protocol data packet received by the terminal device is greater than or equal to a minimum SN value and less than or equal to a maximum SN value.

[00242] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SN value of 1 and a maximum SN value of 5, then when the terminal device determines that the SN value corresponding to the received PDCP protocol data packet is 2, and since the value 2 is greater than the minimum SN value of 1 and less than the maximum SN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00243] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SN value, the maximum SN value and other similar parameters in the embodiments of the present invention.

[00244] In some examples, the SN value may be a section number corresponding to the SN value. Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the section number corresponding to the SN value of the received PDCP protocol data packet matches the section number corresponding to the SN value in the applicable condition.

[00245] It should be understood that the method of segmenting SN values may be specified by the protocol.

[00246] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a section number corresponding to an SN value equal to 1, then when the terminal device determines that the section number corresponding to the SN value of the received PDCP data packet is 1, and since the value 1 matches the section number corresponding to the SN value according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00247] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the section number corresponding to the SN value, and other similar parameters in the embodiments of the present invention.

[00248] In some examples, the SN value may be a parameter pair (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[00249] Accordingly, when the SN value corresponding to the received PDCP protocol data packet belongs to a section with a section number n among m sections, the terminal device can determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device.

[00250] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines, based on an agreement or a message from the network device, that the applicable condition for the HFN information is a parameter pair corresponding to an SN value equal to (2, 1), then when the terminal device determines that the section number containing the SN value corresponding to the received PDCP protocol data packet of the two sections is 1, i.e. the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00251] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the m, n values and other similar parameters in the embodiments of the present invention.

[00252] In some examples, the SFN value may be a minimum SFN value.

[00253] Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the SFN value corresponding to the received PDCP protocol data packet is greater than or equal to the minimum SFN value.

[00254] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SFN value of 5, then when the terminal device determines that the SFN value corresponding to the received PDCP protocol data packet is 7, and since the value 7 is greater than the minimum SFN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00255] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SFN value and other similar parameters in the embodiments of the present invention.

[00256] In some examples, the SFN value may be a minimum SFN value.

[00257] Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the SFN value corresponding to the received PDCP protocol data packet is less than or equal to the maximum SFN value.

[00258] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines, based on an agreement or a message from the network device, that the applicable condition for the HFN information is a maximum SFN value of 5, then when the terminal device determines that the SFN value corresponding to the received PDCP protocol data packet is 1, and since the value 1 is less than the maximum SFN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00259] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the maximum SFN value and other similar parameters in the embodiments of the present invention.

[00260] In some examples, the SFN value may be both a minimum SFN value and a maximum SFN value.

[00261] Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the SFN value corresponding to the received PDCP protocol data packet is greater than or equal to a minimum SFN value and less than or equal to a maximum SFN value.

[00262] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines, based on an agreement or a message from the network device, that the applicable condition for the HFN information is a minimum SFN value of 1 and a maximum SFN value of 5, then when the terminal device determines that the SFN value corresponding to the received PDCP protocol data packet is 2, and since the value 2 is greater than the minimum SFN value of 1 and less than the maximum SFN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00263] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SFN value, the maximum SFN value and other similar parameters in the embodiments of the present invention.

[00264] In some examples, the SFN value may be a section number corresponding to the SFN value. Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device if the section number corresponding to the SFN value of the received PDCP protocol data packet matches the section number corresponding to the SFN value in the applicable condition.

[00265] It should be understood that the method of segmenting SFN values may be specified by the protocol.

[00266] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a section number corresponding to the SFN value equal to 1, then when the terminal device determines that the section number corresponding to the SFN value of the received PDCP data packet is 1, and since the value 1 matches the section number corresponding to the SFN value according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00267] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the section number corresponding to the SFN value, and other similar parameters in the embodiments of the present invention.

[00268] In some examples, the SFN value may be a parameter pair (i, j) corresponding to the SFN value, where i denotes the number of sections after uniformly partitioning all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[00269] Accordingly, when a section containing an SFN value corresponding to a received PDCP protocol data packet has a number j among i sections, the terminal device can determine the HFN value of the PDCP protocol entity based on the HFN information indicated by the network device.

[00270] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines, based on an agreement or a message from the network device, that the applicable condition for the HFN information is a parameter pair corresponding to the SFN value equal to (2, 1), then when the terminal device determines that the SFN value corresponding to the received PDCP protocol data packet is in section number 1 of the two sections, i.e., the applicable condition for the HFN information is met, the terminal device determines that the HFN value of the PDCP protocol entity is 1, based on the HFN value indicated by the network device.

[00271] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the values of i, j and other similar parameters in the embodiments of the present invention.

[00272] For example, a newly connected terminal device may determine a corresponding HFN value based on a determined applicable HFN information condition and the received indication information, and use the HFN value to determine a corresponding COUNT value for the purpose of decrypting or checking the data integrity of a received data packet.

[00273] In embodiments of the present invention, a terminal device may first receive HFN information and an applicable condition for the HFN information transmitted by a network device, and then determine an HFN value of a PDCP protocol entity based on the HFN information if the applicable condition for the HFN information is met. In this way, the terminal device may interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking, and improve the reliability of data transmission.

[00274] Fig. 4 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a terminal device. As shown in Fig. 4, the method may include, among other things, the following actions.

[00275] In step 41, indication information transmitted by the network device is received based on the system message. The indication information includes HFN information.

[00276] For example, a terminal device may receive indication information transmitted by a network device based on a System Information Block (SIB), such as SIB1.

[00277] It should be understood that in the present invention, the network device can extend the SIB1 message to transmit indication information therein. For example, a special bit can be added to the SIB1 block, and its values are configured to indicate an HFN value and/or a COUNT value. Thus, upon receiving the SIB1 message, the terminal device can determine the HFN value and/or the COUNT value in the indication information based on the value of the specified bit, which is not limited by the present invention.

[00278] In some examples, the HFN information includes one or more HFN or COUNT values.

[00279] In some examples, the network device may also transmit indication information to the terminal device in an MBS control channel message so that the terminal device can receive indication information transmitted by the network device based on the MBS control channel message.

[00280] It should be understood that in the present invention, the network device can extend the MBS control channel message to transmit indication information therein. For example, a special bit can be added to the MBS control channel message, and its values are configured to indicate an HFN value and/or a COUNT value. Thus, when receiving the MBS control channel message, the terminal device can determine the HFN value and/or the COUNT value in the indication information based on the value of the specified bit, which is not limited by the present invention.

[00281] In some examples, the network device may also transmit indication information to the terminal device in a separate configuration message of the terminal device so that the terminal device can receive indication information transmitted by the network device based on the separate configuration message of the terminal device.

[00282] It should be understood that in the present invention, the network device can configure the individual configuration message of the terminal device in such a way that the individual configuration message of the terminal device contains indication information. For example, a special bit can be added to the individual configuration message of the terminal device, and its values are configured to indicate the HFN value and/or the COUNT value. Thus, when receiving the individual configuration message of the terminal device, the terminal device can determine the HFN value and/or the COUNT value in the indication information based on the value of the specified bit, which is not limited by the present invention.

[00283] In step 42, if the applicable condition for the HFN information is the SN value, in case of non-fulfillment of the applicable condition and a difference s between the SN value corresponding to the PDCP protocol data packet received by the terminal device and the SN value corresponding to the applicable condition, updated HFN information is generated by updating the HFN information based on the difference s.

[00284] In some examples, the applicable condition for the HFN information may be specified by the network device or may be determined by the terminal device in accordance with an agreement that is not limited by the present invention.

[00285] In some examples, the SN value may be a minimum SN value.

[00286] Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference s if the SN value corresponding to the received PDCP protocol data packet is less than the minimum SN value.

[00287] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SN value of 3, then when the terminal device determines that the SN value corresponding to the received PDCP data packet is 2, and since the value 2 is less than the minimum SN value of 3 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, and the difference s between the SN value corresponding to the PDCP data packet received by the terminal device, equal to 2, and the SN value according to the applicable condition, equal to 3, is -1, then the terminal device generates updated HFN information according to which the HFN value is 0, updating the HFN information based on the difference s.

[00288] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SN value and other similar parameters in the embodiments of the present invention.

[00289] For example, the SN value may be the maximum SN value.

[00290] Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference s if the SN value corresponding to the received PDCP protocol data packet is greater than the maximum SN value.

[00291] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a maximum SN value of 3, then when the terminal device determines that the SN value corresponding to the received PDCP data packet is 4, and since the value 4 is greater than the maximum SN value of 3 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, and the difference s between the SN value corresponding to the PDCP data packet received by the terminal device, equal to 4, and the SN value according to the applicable condition, equal to 3, is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference s.

[00292] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the maximum SN value and other similar parameters in the embodiments of the present invention.

[00293] For example, the SN value may be either a minimum SN value or a maximum SN value.

[00294] Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference s if the SN value corresponding to the received PDCP protocol data packet is less than the minimum SN value or greater than the maximum SN value.

[00295] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SN value of 2 and a maximum SN value of 5, then when the terminal device determines that the SN value corresponding to the received PDCP data packet is 6, and since the value 6 is greater than the maximum SN value of 5 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, and the difference s between the SN value corresponding to the PDCP data packet received by the terminal device equal to 6 and the SN value according to the applicable condition equal to 5 is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference s.

[00296] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SN value, the maximum SN value and other similar parameters in the embodiments of the present invention.

[00297] For example, the SN value may be a section number corresponding to the SN value. Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference s when the section number corresponding to the SN value of the received PDCP data packet differs from the section number corresponding to the SN value in the applicable condition.

[00298] It should be understood that the method of segmenting SN values may be specified by the protocol.

[00299] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a section number corresponding to the SN value of 1, then when the terminal device determines that the section number corresponding to the SN value of the received PDCP data packet is 2, i.e. the applicable condition for the HFN information is not met, and the difference s between the section number corresponding to the SN value of the received PDCP data packet of 2 and the section number according to the applicable condition of 1 is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference s.

[00300] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the section number corresponding to the SN value, and other similar parameters in the embodiments of the present invention.

[00301] For example, the SN value may be a parameter pair (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[00302] Accordingly, when a section containing an SN value corresponding to a received PDCP data packet has a number other than n among m sections, the terminal device may generate updated HFN information by updating the HFN information based on the difference s.

[00303] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a parameter pair corresponding to an SN value equal to (2, 1), then when the terminal device determines that the section number containing the SN value corresponding to the received PDCP data packet of the two sections is 2, i.e. the applicable condition for the HFN information is not met, and the difference s between the section number corresponding to the SN value of the received PDCP data packet equal to 2 and the section number according to the applicable condition equal to 1 is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference s.

[00304] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the m, n values and other similar parameters in the embodiments of the present invention.

[00305] In step 43, the HFN value of the PDCP protocol entity is determined based on the updated HFN information.

[00306] For example, the terminal device may determine the updated HFN value as the HFN value of the PDCP protocol entity.

[00307] For example, for a newly connected terminal device, the HFN value of the PDCP protocol entity may be determined based on a determined applicable condition for the HFN information and the received indication information, and a corresponding COUNT value may be determined using the HFN value for decryption or integrity checking of data in the received data packet.

[00308] In embodiments of the present invention, the terminal device may first receive indication information transmitted by the network device. If, based on the HFN information contained in the indication information and the determined SN value, it is determined that the condition for the determined SN value is not met and the difference between the SN value corresponding to the PDCP data packet received by the terminal device and the determined SN value is s, the terminal device updates the HFN information based on the difference s and determines the HFN value of the PDCP entity based on the updated HFN information. In this way, the terminal device interprets the HFN value in the same way as the network device, in order to avoid a failure in data decryption or a failure in data integrity checking and to improve the reliability of data transmission.

[00309] Fig. 5 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a terminal device. As shown in Fig. 5, the method may include, among other things, the following actions.

[00310] In step 51, indication information transmitted by the network device is received based on a message in the MBS control channel. The indication information includes HFN information.

[00311] For example, the HFN information includes one or more HFN or COUNT values.

[00312] It should be noted that information about the content and specific form of presentation of the indication information received by the terminal device based on the MBS control channel message can be found in the description of other embodiments of the present invention and will not be repeated here.

[00313] In step 52, if the applicable condition is an SFN value, in case of non-fulfillment of the applicable condition and a difference k between the SFN value corresponding to the PDCP protocol data packet received by the terminal device and the SFN value corresponding to the applicable condition, updated HFN information is generated by updating the HFN information based on the difference k.

[00314] For example, the applicable condition for the HFN information may be specified by the network device or may be determined by the terminal device according to the agreement, which is not limited by the present invention.

[00315] For example, the SFN value corresponding to the PDCP protocol data packet received by the terminal device includes any of the following values: an SFN value corresponding to the temporary location of the last physical data channel in which the PCDP protocol data packet is successfully received; an SFN value corresponding to the temporary location of the first physical data channel in which the PCDP protocol data packet is successfully received; or an SFN value corresponding to the successful reception of the PDCP protocol data packet.

[00316] For example, the SFN value corresponding to the PDCP data packet received by the terminal device is the SFN value corresponding to the time location of the last physical data channel in which the PCDP data packet is successfully received. When receiving the PDCP data packet, the terminal device must successfully receive the physical downlink shared channel (PDSCH) data at the time t1 and the PDSCH data at the time t2 (where the time t1 precedes the time t2), and then the terminal device can determine the SFN value corresponding to the time t2 as the SFN value corresponding to the PDCP data packet received by the terminal device, which is not limited to the present invention.

[00317] Or, the SFN value corresponding to the PDCP data packet received by the terminal device is the SFN value corresponding to the time location of the first physical data channel in which the PCDP data packet is successfully received. When receiving the PDCP data packet, the terminal device must successfully receive the PDSCH data at the time t1 and the PDSCH data at the time t2 (where the time t1 is before the time t2), and then the terminal device can determine the SFN value corresponding to the time t2 as the SFN value corresponding to the PDCP data packet received by the terminal device, which is not limited to the present invention.

[00318] Or, the SFN value corresponding to the PDCP data packet received by the terminal device is the SFN value corresponding to the successful reception of the PDCP data packet. For example, if, when receiving the PDCP data packet, the successful reception of the PDCP channel data occurs at the time t3, the terminal device may determine the SFN value corresponding to the time t3 as the SFN value corresponding to the PDCP data packet received by the terminal device, which is not limited to the present invention.

[00319] For example, the SFN value may be the maximum SFN value.

[00320] Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference k if the SFN value corresponding to the received PDCP protocol data packet is less than the minimum SFN value.

[00321] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SFN value of 3, then when the terminal device determines that the SFN value corresponding to the received PDCP data packet is 2, and since the value 2 is less than the minimum SFN value of 3 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, and the difference k between the SFN value corresponding to the PDCP data packet received by the terminal device equal to 2 and the SFN value according to the applicable condition equal to 3 is -1, then the terminal device generates updated HFN information according to which the HFN value is 0, updating the HFN information based on the difference k.

[00322] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SFN value and other similar parameters in the embodiments of the present invention.

[00323] For example, the SFN value may be the maximum SFN value.

[00324] Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference k if the SFN value corresponding to the received PDCP protocol data packet is greater than the maximum SFN value.

[00325] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a maximum SFN value of 3, then when the terminal device determines that the SFN value corresponding to the received PDCP protocol data packet is 4, and since the value 4 is greater than the maximum SFN value of 3 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, and the difference k between the SFN value corresponding to the PDCP protocol data packet received by the terminal device equal to 4 and the SFN value according to the applicable condition equal to 3 is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference k.

[00326] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the maximum SFN value and other similar parameters in the embodiments of the present invention.

[00327] For example, the SFN value may be either a minimum SFN value or a maximum SFN value.

[00328] Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference k if the SFN value corresponding to the received PDCP protocol data packet is less than the minimum SFN value or greater than the maximum SFN value.

[00329] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SFN value of 2 and a maximum SFN value of 5, then when the terminal device determines that the SFN value corresponding to the received PDCP data packet is 6, and since the value 6 is greater than the maximum SFN value of 5 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, and the difference k between the SFN value corresponding to the PDCP data packet received by the terminal device, equal to 6, and the maximum SFN value according to the applicable condition, equal to 5, is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference k.

[00330] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SFN value, the maximum SFN value and other similar parameters in the embodiments of the present invention.

[00331] For example, the SFN value may be a section number corresponding to the SFN value. Accordingly, the terminal device may generate updated HFN information by updating the HFN information based on the difference k when the section number corresponding to the SFN value of the received PDCP data packet differs from the section number corresponding to the SFN value in the applicable condition.

[00332] It should be understood that the method of segmenting SFN values may be specified by the protocol.

[00333] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a section number corresponding to the SFN value of 1, then when the terminal device determines that the section number corresponding to the SFN value of the received PDCP data packet is 2, i.e. the applicable condition for the HFN information is not met, and the difference k between the section number corresponding to the SFN value of the received PDCP data packet of 2 and the section number according to the applicable condition of 1 is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference k.

[00334] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the section number corresponding to the SFN value, and other similar parameters in the embodiments of the present invention.

[00335] For example, an SFN value may be a parameter pair (i, j) corresponding to the SFN value, where i denotes the number of sections after uniformly dividing all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[00336] Accordingly, when a section containing an SFN value corresponding to a received PDCP data packet has a number different from j among i sections, the terminal device may generate updated HFN information by updating the HFN information based on the difference k.

[00337] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a parameter pair corresponding to the SFN value equal to (2, 1), then when the terminal device determines that the section number containing the SFN value corresponding to the received PDCP data packet of the two sections is 2, i.e. the applicable condition for the HFN information is not met, and the difference k between the section number corresponding to the SFN value of the received PDCP data packet equal to 2 and the section number according to the applicable condition equal to 1 is +1, then the terminal device generates updated HFN information according to which the HFN value is 2, updating the HFN information based on the difference k.

[00338] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the values of i, j and other similar parameters in the embodiments of the present invention.

[00339] In step 53, the HFN value of the PDCP protocol entity is determined based on the updated HFN information.

[00340] For example, the terminal device may determine the updated HFN value as the HFN value of the PDCP protocol entity.

[00341] For example, for a newly connected terminal device, the HFN value of the PDCP protocol entity may be determined based on a determined applicable condition for the HFN information and the received indication information, and a corresponding COUNT value may be determined using the HFN value for decryption or integrity checking of data in the received data packet.

[00342] In embodiments of the present invention, the terminal device may first receive indication information transmitted by the network device. If, based on the HFN information contained in the indication information and the determined SFN value, it is determined that the condition for the SFN value is not met and the difference between the SFN value corresponding to the PDCP data packet received by the terminal device and the determined SFN value is k, the terminal device updates the HFN information based on the difference k and determines the HFN value of the PDCP protocol entity based on the updated HFN information. In this way, the terminal device can interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking and improve the reliability of data transmission.

[00343] Fig. 6 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a terminal device. As shown in Fig. 6, the method may include, among other things, the following actions.

[00344] In step 61, indication information transmitted by the network device is received. The indication information includes HFN information and an update mode of the HFN information.

[00345] In embodiments of the present invention, when sending HFN information to a terminal device, a network device may determine an update mode of the HFN information depending on a current network status, such as a transmission rate of a PDCP data packet, and send the update mode information to the terminal device to avoid a situation in which the HFN information received by the terminal device is inaccurate due to a poor network status.

[00346] For example, the HFN information includes one or more HFN or COUNT values.

[00347] For example, the update mode includes an update step size and an update direction.

[00348] The update step size may be any value set by the network device, such as 1, 2 or 3, which is not limited by the present invention.

[00349] In addition, the updating direction may be any direction set by the network device, for example, the direction indicated by the symbol "+", the direction indicated by the symbol "-", and other similar embodiments, which is not limited to the present invention. Therefore, the updating mode of the HFN information may be as follows: "the HFN value determined by the indication information +1", "the HFN value determined by the indication information - 2", "the COUNT value determined by the indication information - 1", and other similar embodiments, which is not limited to the present invention.

[00350] In step 62, if the applicable condition is not met, updated HFN information is generated by updating the HFN information depending on the update mode.

[00351] For example, the applicable condition for the HFN information may be specified by the network device or may be determined by the terminal device according to an agreement, which is not limited by the present invention.

[00352] For example, when a PDCP data packet is transmitted too quickly, the PDCP data packet received by the terminal device may not satisfy the applicable condition for the HFN information. At this point, the HFN information update mode indicated by the network device may be "HFN value determined by the indication information + 1". When a PDCP data packet is transmitted too slowly, the PDCP data packet received by the terminal device may not satisfy the applicable condition for the HFN information. At this point, the HFN information update mode indicated by the network device may be "HFN value determined by the indication information - 1" or "HFN value determined by the indication information - 2", which is not limited to the present invention.

[00353] For example, an applicable condition for the HFN information is a minimum SN value. Accordingly, the terminal device may update the HFN information depending on the update mode to generate updated HFN information if the SN value corresponding to the received PDCP protocol data packet is less than the minimum SN value.

[00354] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the direction is the HFN value specified by the indication information is 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SN value of 3, then when the terminal device determines that the SN value corresponding to the received PDCP protocol data packet is 2, and since the value 2 is less than the minimum SN value of 3 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, then the terminal device can update the HFN information, and the updated HFN value is 0.

[00355] Or, the applicable condition for the HFN information is the maximum SFN value. Accordingly, the terminal device may update the HFN information depending on the update mode to generate updated HFN information if the SFN value corresponding to the received PDCP protocol data packet is greater than the maximum SFN value.

[00356] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the direction is the HFN value determined by the indication information + 1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is the maximum SFN value of 3, then when the terminal device determines that the SFN value corresponding to the received PDCP protocol data packet is 4, and since the value 4 is greater than the maximum SFN value of 3 according to the applicable condition, i.e. the applicable condition for the HFN information is not met, then the terminal device can update the HFN information, wherein the updated HFN value is 2.

[00357] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SFN value, the maximum SFN value and other similar parameters in the embodiments of the present invention.

[00358] It should be noted that the updated content and specific form of presentation of the HFN information depending on the updating mode in other cases where the applicable condition for the HFN information is not met are given in the description of other embodiments of the present invention and will not be repeated here.

[00359] In step 63, the HFN value of the PDCP protocol entity is determined based on the updated HFN information.

[00360] For example, the terminal device may determine the updated HFN value as the HFN value of the PDCP protocol entity.

[00361] For example, for a newly connected terminal device, the HFN value of the PDCP protocol entity may be determined based on a certain applicable condition for the HFN information and the received indication information, and the HFN number may be used to determine a corresponding COUNT value for the purpose of decrypting or checking the integrity of data in a received data packet.

[00362] In embodiments of the present invention, the terminal device may first receive indication information transmitted by the network device. Based on the HFN information contained in the indication information and the determined applicable information condition for the HFN information, if the applicable condition for the HFN information is not met, the terminal device updates the HFN information depending on the update mode to generate updated HFN information, and then determines the HFN value of the PDCP protocol entity. In this way, the terminal device can interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking and improve the reliability of data transmission.

[00363] Fig. 7 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a terminal device. As shown in Fig. 7, the method may include, among other things, the following actions.

[00364] In step 71, indication information transmitted by the network device is received. The indication information includes HFN information and MBS service information.

[00365] For example, the HFN information includes one or more HFN or COUNT values.

[00366] For example, the MBS service information includes at least one of the following types of information: an MBS service ID, an MBS channel identifier, or MBS channel protocol entity configuration information.

[00367] The MBS service identifier may include a Temporary Mobile Group Identity (TMGI), an MBS session identifier, and an MBS Quality of Service (QoS) flow identifier, which is not limited to the present invention.

[00368] Furthermore, the format or form of representation of the MBS channel identifier may be specified by the protocol or configured by the network device, such as MRB-1 or MRB-2, which is not limited by the present invention.

[00369] For example, the configuration information of the MBS channel protocol entity may be the configuration information of the PDCP protocol. The configuration information of the PDCP protocol may include: the length of the PDCP protocol SN number, the configuration of the packet header compression, or the configuration of the need for integrity checking.

[00370] Alternatively, the configuration information of the MBS channel protocol entity may be a Radio Link Control (RLC) configuration. The RLC configuration may include: the length of the PDCP protocol SN number, an indication of the RLC operating mode, or similar parameters.

[00371] Alternatively, the MBS channel protocol entity configuration information may be a medium access control (MAC) configuration, which may include a logical channel identifier and is not limited to the present invention.

[00372] In step 72, the HFN value of the PDCP protocol entity corresponding to the MBS service information is determined based on the HFN information.

[00373] For example, the indication information received by the terminal device indicates that the HFN value for MRB-1 is 1. Therefore, the terminal device can determine that the HFN value of the PDCP protocol entity corresponding to MRB-1 is 1, which is not limited to the present invention.

[00374] For example, the terminal device may determine the HFN value of the PDCP protocol entity corresponding to the MBS service information based on the HFN information if the SN value corresponding to the received PDCP protocol data packet satisfies the applicable condition for the HFN information.

[00375] For example, the SN value may be a minimum SN value. Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity corresponding to the MBS service information based on the HFN information indicated by the network device if the SN value corresponding to the received PDCP protocol data packet is greater than or equal to this minimum SN value.

[00376] For example, the PDCP data packet received by the terminal device may be the first PDCP data packet received by the terminal device from the MRB corresponding to the MBS service information.

[00377] For example, if the indication information received by the terminal device indicates that the HFN value is 1, and the radio channel corresponding to the MBS service information is MRB-1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a minimum SN value of 5, and the PDCP data packet received by the terminal device may be the first PDCP data packet received by the terminal device from MRB-1, then when the terminal device determines that the SN value corresponding to the received PDCP data packet is 7, and since the value 7 is greater than the minimum SN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity corresponding to MRB-1 is 1, based on the HFN value indicated by the network device.

[00378] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the minimum SN value and other similar parameters in the embodiments of the present invention.

[00379] For example, the terminal device may determine an HFN value of a PDCP protocol entity corresponding to the MBS service information based on the HFN information if the SFN value corresponding to the received PDCP protocol data packet satisfies an applicable condition for the HFN information.

[00380] For example, the SFN value may be a maximum SFN value. Accordingly, the terminal device may determine the HFN value of the PDCP protocol entity corresponding to the MBS service information based on the HFN information indicated by the network device if the SFN value corresponding to the received PDCP protocol data packet is less than or equal to this maximum SFN value.

[00381] For example, if the indication information received by the terminal device indicates that the HFN value is 1 and the radio bearer corresponding to the MBS service information is MRB-1, and the terminal device determines based on an agreement or a message from the network device that the applicable condition for the HFN information is a maximum SFN value of 5, then when the terminal device determines that the SFN value corresponding to the received PDCP protocol data packet is 1, and since the value 1 is less than the maximum SFN value of 5 according to the applicable condition, i.e., the applicable condition for the HFN information is met, then the terminal device determines that the HFN value of the PDCP protocol entity corresponding to MRB-1 is 1, based on the HFN value indicated by the network device.

[00382] It should be noted that the above examples are merely illustrative and cannot be considered as a limitation imposed on the indication information, the HFN value, the maximum SFN value and other similar parameters in the embodiments of the present invention.

[00383] It should be noted that the specific content and method of representing the HFN value of the PDCP protocol entity corresponding to the MBS service information when the SN value or the SFN value satisfies other applicable conditions of the HFN information are described in the description of other embodiments of the present invention and are not repeated here.

[00384] For example, for a terminal device that has just connected to an MBS service, the HFN value of the PDCP protocol object corresponding to the MBS service information may be determined based on the HFN information.

[00385] For example, if the indication information received by a terminal device newly connected to the MBS service indicates that the HFN value is 1 and the radio bearer corresponding to the MBS service is MRB-1, then the terminal device may determine the HFN value of the PDCP protocol entity corresponding to MRB-1, which is not limited to the present invention.

[00386] In step 73, decryption or integrity checking of the received data corresponding to the MBS service information is performed based on the HFN information.

[00387] For example, after the terminal device determines that the HFN value of the PDCP protocol entity corresponding to MRB-1 is 1, the terminal device uses the HFN value to determine the corresponding COUNT value, and then performs decryption or integrity checking of the received data corresponding to MRB-1, which is not limited to the present invention.

[00388] In embodiments of the present invention, the terminal device may first receive indication information transmitted by the network device, determine an HFN value of the PDCP protocol entity corresponding to the MBS service information based on the HFN information and the MBS service information contained in the indication information, and perform decryption or integrity check of the received data corresponding to the MBS service information. In this way, the terminal device may interpret the HFN value in the same way as the network device, so as to avoid a failure in decrypting the data or a failure in checking the integrity of the data and improve the reliability of data transmission.

[00389] Fig. 8 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a network device. As shown in Fig. 8, the method may include, among other things, the following actions.

[00390] In step 81, indication information is transmitted to the terminal device. The indication information includes HFN information.

[00391] For example, the HFN information includes one or more HFN and COUNT values.

[00392] For example, the network device may transmit indication information to the terminal device based on the system message. The indication information includes HFN information.

[00393] For example, the network device may extend the SIFJ1 message to convey indication information therein. For example, a special bit may be added to the SIB1 block, wherein its values are configured to indicate the HFN value and/or the COUNT value, which is not limited by the present invention.

[00394] For example, a network device may transmit indication information to a terminal device based on an MBS control channel message.

[00395] It should be understood that in the present invention, the network device may extend the MBS control channel message to convey indication information therein. For example, a special bit may be added to the MBS control channel message, and its values may be configured to indicate the HFN value and/or the COUNT value, which is not limited to the present invention.

[00396] For example, a network device may transmit indication information to a terminal device based on a separate configuration message of the terminal device.

[00397] It should be understood that in the present invention, the network device can extend the separate configuration message of the terminal device so that the separate configuration message of the terminal device contains indication information. For example, a special bit can be added to the separate configuration message of the terminal device, and its values can be configured so as to indicate the HFN value and/or the COUNT value, which is not limited by the present invention.

[00398] In embodiments of the present invention, the network device may transmit indication information to the terminal device so that the terminal device can receive the HFN information. In this way, the terminal device can interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking and to improve the reliability of data transmission.

[00399] Fig. 9 is a flow chart illustrating a method for determining an HFN number of a PDCP protocol entity in accordance with embodiments of the present invention. This method is implemented by a network device. As shown in Fig. 9, the method may include, among other things, the following actions.

[00400] In step 91, indication information is transmitted to the terminal device based on the system message. The indication information includes HFN information.

[00401] For example, the network device may extend the SIB1 message to convey indication information therein. For example, a special bit may be added to the SIB1 block, and its values may be configured to indicate an HFN value and/or a COUNT value, which is not limited by the present invention.

[00402] The HFN information includes one or more HFN and COUNT values.

[00403] In step 92, the applicable condition for the HFN information is transmitted to the terminal device.

[00404] For example, an applicable condition for HFN information includes one or more SN or SFN values.

[00405] The SN value includes one or more of the following values: a minimum SN value; a maximum SN value; both the minimum SN value and the maximum SN value; a section number corresponding to the SN value; or a parameter pair (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the section number containing the current SN value among m sections, where n is an integer less than or equal to m.

[00406] For example, the SFN value includes one or more of the following values: a minimum SFN value; a maximum SFN value; both the minimum SFN value and the maximum SFN value; a section number corresponding to the SFN value; or a pair of parameters (i, j) corresponding to the SFN value, where i denotes the number of sections after equally segmenting all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among i sections, where j is an integer less than or equal to i.

[00407] It should be noted that the operations performed by the terminal device based on the applicable condition for the HFN information and the corresponding effects are described with respect to the terminal device side in other embodiments of the present invention and are not repeated here.

[00408] For example, the indication information further includes information about the MBS service.

[00409] The MBS service information includes at least one of the following types of information: an MBS service ID, an MBS channel identifier, or MBS channel protocol entity configuration information.

[00410] For example, the indication information further includes an HFN information update mode.

[00411] For example, the update mode includes an update step size and an update direction.

[00412] The update step size may be a value set by the network device depending on the transmission rate of the PDCP protocol data packet, for example, 1, 2 or 3, which is not limited to the present invention.

[00413] In addition, the update direction may be a direction set by the network device, for example, a direction indicated by the symbol “+”, a direction indicated by the symbol “-”, or other similar embodiments, which is not limited to the present invention.

[00414] For example, when a PDCP data packet is transmitted too quickly, there is a possibility that the PDCP data packet received by the terminal device will not satisfy the applicable condition for the HFN information. At this point, the HFN information update mode indicated by the network device may be "HFN value determined by the indication information + 1". When a PDCP data packet is transmitted too slowly, there is a possibility that the PDCP data packet received by the terminal device will not satisfy the applicable condition for the HFN information. At this point, the HFN information update mode indicated by the network device may be "HFN value determined by the indication information - 1" or "HFN value determined by the indication information - 2", which is not limited to the present invention.

[00415] It should be noted that the operations performed by the terminal device based on various indication information and the corresponding effects are described with respect to the terminal device side in other embodiments of the present invention and are not repeated here.

[00416] In step 93, if any change in the information in the system message other than the HFN information occurs, first change indication information is transmitted to the terminal device.

[00417] It should be understood that in order to reduce the amount of data to be transmitted, when the network device transmits indication information to the terminal device using a system message, the network device may transmit the first indication information about a change to the terminal device whenever the information in the system message changes except for the HFN information. Therefore, if the HFN value in the system message changes, the network device does not transmit the first indication information about a change to the terminal device, which reduces the amount of data to be transmitted, and the terminal device can interpret the HFN value in the same way as the network device, thereby ensuring the reliability of data transmission.

[00418] For example, in the case of a change in the information in the MBS control channel message, in addition to the HFN information, the network device transmits to the terminal device the second change indication information; Therefore, if the HFN value in the MBS control channel message changes, the network device does not transmit to the terminal device the second change indication information, which reduces the amount of data to be transmitted, and the terminal device can interpret the HFN value in the same way as the network device, thereby ensuring the reliability of data transmission.

[00419] In embodiments of the present invention, the network device may transmit indication information to the terminal device using a system message so that the terminal device can receive the HFN information. The network device may also transmit to the terminal device an applicable condition for the HFN information, and also transmit to the terminal device the first change indication information when any change in the information in the system message other than the HFN information occurs. In this way, the terminal device can interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking and to improve the reliability of data transmission.

[00420] The methods according to the above embodiments of the present invention are described from the perspective of a network device and a terminal device, respectively. In order to implement each of the functions in the methods according to the above embodiments of the present invention, the network device and the terminal device may include a hardware structure, a software module, and implement each of the specified functions as a hardware structure, a software module, or a combination of a hardware structure and a software module. A certain function from the above may be implemented as a hardware structure, a software module, or a combination of a hardware structure and a software module.

[00421] Fig. 10 is a block diagram of a communication device 100 according to embodiments of the present invention. The communication device 100 shown in Fig. 10 may include a transceiver module 1001 and a processing module 1002.

[00422] The transceiver module 1001 may include a transmitting module and/or a receiving module. The transmitting module is configured to perform a transmitting function, and the receiving module is configured to perform a receiving function, so that the transceiver module 1001 can perform a transmitting function and/or a receiving function.

[00423] It should be understood that the communication device 100 may be a terminal device, a device included in a terminal device, or a device capable of being used in combination with a terminal device.

[00424] The communication device 100, configured on the terminal device side, includes: a transceiver module 1001 and a processing module 1002.

[00425] The transceiver module is configured to receive indication information transmitted by the network device, wherein the indication information includes HFN information.

[00426] The processing module 1002 is configured to determine the HFN value of the PDCP protocol entity based on the HFN information.

[00427] For example, the HFN information includes one or more HFN or COUNT values.

[00428] For example, the processing module 1002 is configured to determine the HFN value of the PDCP protocol entity based on the HFN information when the applicable condition for the HFN information is met.

[00429] For example, the transceiver module 1001 is configured to receive an applicable condition for HFN information transmitted by the network device;

[00430] or

[00431] the processing module 1002 is configured to determine an applicable condition for the HFN information based on the agreement.

[00432] For example, an applicable condition for HFN information includes one or more SN or SFN values.

[00433] For example, the SN value includes one or more of the following values:

[00434] minimum SN value;

[00435] maximum SN value;

[00436] minimum SN value and maximum SN value;

[00437] the section number corresponding to the SN value; or

[00438] a pair of parameters (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[00439] For example, an SFN value includes one or more of the following values:

[00440] minimum SFN value;

[00441] maximum SFN value;

[00442] minimum SFN value and maximum SFN value;

[00443] the section number corresponding to the SFN value; or

[00444] a pair of parameters (i, j) corresponding to an SFN value, where i denotes the number of sections after uniformly dividing all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[00445] For example, an applicable condition that must be met includes:

[00446] an SN value corresponding to a PDCP protocol data packet received by the terminal device and satisfying the applicable condition;

[00447] or

[00448] the SFN value corresponding to the PDCP protocol data packet received by the terminal device and satisfying the applicable condition.

[00449] For example, the indication information further includes information about the MBS service, and the received PDCP protocol data packet is the first PDCP protocol data packet received by the terminal device from the MRB corresponding to the information about the MBS service.

[00450] For example, the SFN value corresponding to a received PDCP protocol data packet includes one or more of the following values:

[00451] an SFN value corresponding to the time position of the last physical data channel in which a PCDP protocol data packet was successfully received;

[00452] an SFN value corresponding to the time position of the first physical data channel in which a PCDP protocol data packet is successfully received; and

[00453] SFN value corresponding to a successfully received PDCP protocol data packet.

[00454] For example, the applicable condition is an SN value, and the processing module 1002 is configured to: if the applicable condition is not met and a difference between the SN value corresponding to the PDCP data packet received by the terminal device and the SN value according to the applicable condition is s, generate updated HFN information based on the difference s; and determine the HFN value of the PDCP protocol entity based on the updated HFN information.

[00455] For example, the applicable condition is an SFN value, and the processing module 1002 is configured to: if the applicable condition is not met and a difference between the SFN value corresponding to the PDCP protocol data packet received by the terminal device and the SFN value according to the applicable condition is k, generate updated HFN information based on the difference k; and determine the HFN value of the PDCP protocol entity based on the updated HFN information.

[00456] For example, the indication information further comprises an indication of an update mode of the HFN information, and the processing module 1002 is configured to: generate updated HFN information by updating the HFN information depending on the update mode if the applicable condition is not met; and determine an HFN value of the PDCP protocol entity based on the updated HFN information.

[00457] For example, the update mode includes an update step size and an update direction.

[00458] For example, the transceiver module 1001 is configured to: receive indication information transmitted by a network device based on a system message; or receive indication information transmitted by a network device based on a message in an MBS control channel; or receive indication information transmitted by a network device based on a separate configuration message of a terminal device.

[00459] For example, the indication information further includes information about the MBS service, and the processing module 1002 is configured to: determine an HFN value of a PDCP protocol entity corresponding to the information about the MBS service based on the HFN information.

[00460] For example, the MBS service information includes at least one of the following types of information: an MBS service ID, an MBS channel identifier, or MBS channel protocol entity configuration information.

[00461] For example, the processing module 1002 is configured to decrypt received data corresponding to the MBS service information or check the integrity thereof based on the HFN information.

[00462] For example, the processing module 1002 is configured to determine the HFN value of the PDCP protocol entity based on the HFN information if the terminal device starts accessing the MBS service.

[00463] In the communication device according to the present invention, the terminal device may first receive the indication information transmitted by the network device, and determine the HFN value of the PDCP protocol entity based on the HFN information included in the indication information. In this way, the terminal device may interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking, and improve the reliability of data transmission.

[00464] Fig. 11 is a block diagram of a communication device 110 according to embodiments of the present invention. The communication device 110 shown in Fig. 11 may include a transceiver module 1101.

[00465] The transceiver module 1101 may include a transmitting module and/or a receiving module. The transmitting module is configured to perform a transmitting function, and the receiving module is configured to perform a receiving function, so that the transceiver module 1101 can perform a transmitting function and/or a receiving function.

[00466] It should be understood that the communication device 110 may be a network device, a device included in a network device, or a device capable of being used in combination with a network device.

[00467] The communication device 110, configured on the network device side, includes: a transceiver module 1001.

[00468] The transceiver module 1101 is configured to transmit indication information to the terminal device, wherein the indication information includes HFN information.

[00469] For example, the HFN information includes one or more HFN or COUNT values.

[00470] For example, the transceiver module is configured to transmit an applicable condition for the HFN information to the terminal device.

[00471] For example, an applicable condition for HFN information includes one or more SN or SFN values.

[00472] For example, the SN value includes one or more of the following values:

[00473] minimum SN value;

[00474] maximum SN value;

[00475] minimum SN value and maximum SN value;

[00476] the section number corresponding to the SN value; or

[00477] a pair of parameters (m, n) corresponding to the SN value, where m denotes the number of sections after uniformly dividing all SN values into sections in a certain order, and n denotes the number of the section containing the current SN value among all m sections, where n is an integer less than or equal to m.

[00478] For example, an SFN value includes one or more of the following values:

[00479] minimum SFN value;

[00480] maximum SFN value;

[00481] minimum SFN value and maximum SFN value;

[00482] the section number corresponding to the SFN value; or

[00483] a pair of parameters (i, j) corresponding to an SFN value, where i denotes the number of sections after uniformly dividing all SFN values into sections in a certain order, and j denotes the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i.

[00484] For example, the indication information further includes information about the MBS service.

[00485] For example, the MBS service information includes at least one or more of the following types of information: an MBS service ID, an MBS channel identifier, or MBS channel protocol entity configuration information.

[00486] For example, the indication information further includes an HFN information update mode.

[00487] For example, the update mode includes an update step size and an update direction.

[00488] For example, the second transceiver module 1101 is configured to: transmit indication information to the terminal device based on a system message; or transmit indication information to the terminal device based on a message in the MBS control channel; or transmit indication information to the terminal device based on a separate configuration message of the terminal device.

[00489] For example, the transceiver module 1101 is configured to: transmit first change indication information to the terminal device when any change in information in the system message other than the HFN information occurs; or transmit second change indication information to the terminal device when any change in information in the MBS control channel message other than the HFN information occurs.

[00490] In the communication device according to the present invention, the network device can transmit indication information to the terminal device so that the terminal device can receive the HFN information. In this way, the terminal device can interpret the HFN value in the same way as the network device, so as to avoid a failure in data decryption or a failure in data integrity checking and improve the reliability of data transmission.

[00491] Fig. 12 shows a block diagram of a communication device 120 according to embodiments of the present invention. The communication device 120 may be a network device, a terminal device, a chip, a system based on a chip, or a processor that supports a network device for implementing the methods described above, or a chip, a system based on a chip, or a processor that supports a terminal device for implementing the methods described above. The device may be used to implement the methods described in the above embodiments of the method, so for more detailed information, reference may be made to the descriptions of the above embodiments of the method.

[00492] The communication device 120 may include one or more processors 1201. The processor 1201 may be a general-purpose processor or a specialized processor, such as a baseband processor or a central processor. The baseband processor is used to process communication protocols and communication data. The central processor is used to control the communication device (such as a base station, a baseband chip, a terminal device, a terminal device chip, a DU or a CU), execute a computer program, and process computer program data.

[00493] For example, the communication device 120 may comprise one or more memory units 1202, in which computer programs 1204 may be stored. The processor 1201 executes the computer programs 1204 in such a way as to cause the communication device 120 to implement the methods described in the above embodiments of the method. In one embodiment, data may also be stored in the memory 1202. The communication device 120 and the memory 1202 may be implemented separately or combined together.

[00494] For example, the communication device 120 may also include a transceiver 1205 and an antenna 1206. From the perspective of implementing the reception/transmission function, the transceiver 1205 may be called a transceiver unit, a transceiver device, or a transceiver circuit. The transceiver 1205 may include a receiver and a transmitter. From the perspective of implementing the reception function, the receiver may be called a receiving device or a receiving circuit. From the perspective of implementing the transmission function, the transmitter may be called a transmitting device or a transmitting circuit.

[00495] For example, the communication device 120 may also include one or more interface circuits 1207. The interface circuits 1207 are used to receive code instructions and transmit them to the processor 1201. The processor 1201 executes the code instructions 1004 in such a way as to cause the communication device 120 to implement the method described in the embodiments of the method.

[00496] The communication device 120 is a terminal device. The processor 1201 is configured to perform step 22 in Fig. 2, step 32 in Fig. 3, step 42 in Fig. 4, step 43 in Fig. 4, step 52 in Fig. 5, step 53 in Fig. 5, step 62 in Fig. 6, step 63 in Fig. 6, step 72 in Fig. 7, or step 73 in Fig. 7. The transceiver 1205 is used to perform step 21 in Fig. 2, step 31 in Fig. 3, step 41 in Fig. 4, step 51 in Fig. 5, step 61 in Fig. 6, or step 71 in Fig. 7.

[00497] The communication device 120 is a network device. The transceiver 1205 is used to perform step 81 in Fig. 8, step 91 in Fig. 9, step 92 in Fig. 9, or step 93 in Fig. 9.

[00498] In one embodiment, the processor 1201 may include a transceiver for performing reception and transmission functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing the reception and transmission functions may be separated or combined. The transceiver circuit, interface, or interface circuit described above may be used to read and write code/data or to transmit or deliver a signal.

[00499] In one embodiment, the processor 1201 may store a computer program 1203 that is executed on the processor 1201 to cause the communication device 120 to implement the methods described in the above embodiments of the method. The computer program 1203 may be implemented in the processor 1201, wherein the processor 1201 may be implemented in hardware.

[00500] In one embodiment, the communication device 120 may include a circuit. In the previous embodiments of the method, the circuits may implement a transmitting, receiving, or communicating function. The processors and transceivers described in this invention may be implemented as integrated circuits (IC, Integrated Circuit), analog integrated circuits, radio frequency integrated circuits (RFIC, Radio Frequency IC), analog-to-digital integrated circuits, application specific integrated circuits (ASIC, Application Specific IC), printed circuit boards (PCB), or other electronic devices. Processors and transceivers can also be manufactured using various IC manufacturing technologies, such as complementary metal-oxide-semiconductor (CMOS), n-channel metal-oxide-semiconductor (nMOS), p-channel metal-oxide-semiconductor (pMOS), bipolar transistors (BJT, Bipolar Junction Transistor), combined bipolar and CMOS structures (BiCMOS), silicon-germanium (SiGe), gallium arsenide (GaAs), and others.

[00501] The communication device in the above embodiments may be a network device or a terminal device, but the field of application of the communication device described in the present invention is not limited to these embodiments, and the structure of the communication device is not limited to Fig. 12. The communication device may be either a stand-alone device or a part of a larger device. For example, the communication device may be:

[00502] (1) a separate integrated circuit, microcircuit, microcircuit-based system, or microcircuit-based subsystem;

[00503] (2) a set of ICs that includes one or more ICs, wherein in one embodiment, the set of ICs may also include memory components for storing data and computer programs;

[00504] (3) a specialized integrated circuit, such as a modem;

[00505] (4) modules that can be built into other devices;

[00506] (5) receivers, terminal devices, intelligent terminal devices, cellular phones, wireless devices, portable devices, mobile devices, on-board devices, network devices, cloud devices, artificial intelligence devices and other similar devices; and

[00507] (6) other similar devices.

[00508] If the communication device is a microcircuit or a system based on a microcircuit, then the microcircuit diagram in Fig. 13 can be cited as an example. The microcircuit in Fig. 13 includes a processor 1301 and an interface 1302. There may be one or more processors 1301, and there may be a plurality of interfaces 1302.

[00509] If the microcircuit is used to implement the functions of the terminal device according to embodiments of the present invention,

[00510] The interface 1302 is used to perform step 21 in Fig. 2, step 31 in Fig. 3, step 41 in Fig. 4, step 51 in Fig. 5, step 61 in Fig. 6, or step 71 in Fig. 7.

[00511] If the chip is used to implement the functions of the network device according to embodiments of the present invention, the interface 1302 is used in such a way as to perform step 81 in Fig. 8, step 91 in Fig. 9, step 92 in Fig. 9, step 93 in Fig. 9

[00512] For example, the microcircuit further includes a memory 1303 used to store necessary computer programs and data.

[00513] It should be understood by those skilled in the art that the various logical blocks and steps given in the exemplary embodiments of the present invention may be implemented using electronic hardware, computer software, or a combination thereof. Whether such a function is implemented by hardware or software depends on the specific application and the technical requirements of the overall system. In order to implement the described functions in each specific case, those skilled in the art use various methods, and such implementation should not be considered as going beyond the scope of protection of the present invention.

[00514] In embodiments of the present invention, a communication system is also provided. The communication system includes a communication device that is a terminal device in the above-mentioned embodiment of Fig. 10, and a communication device that is a network device in the embodiment of Fig. 11. Or, the communication system includes a communication device that is a terminal device and a communication device that is a network device in the above-described embodiment of Fig. 12.

[00515] The present invention also provides a computer-readable storage medium on which instructions are stored. When the instructions are executed by a computer, a function is implemented according to any of the above-described embodiments of the method.

[00516] The present invention also provides a computer program product. When executing the computer program product, a function is implemented according to any of the above-described embodiments of the method.

[00517] In the above embodiments, the method may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, the method may be implemented in whole or in part by a computer program product. The computer program product includes one or more computer programs. When the computer program is loaded and executed, all or part of the processes or functions described in the embodiments of the present invention are implemented on the computer. The computer may be a general-purpose computer, a specialized computer, a computer network, or other programmable devices. The computer program may be stored on a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, a computer program may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic cable, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave) channels. A computer-readable storage medium may be any usable medium that is accessible by a computer or a data storage device such as a server and data center integrated with one or more usable media. A usable medium may be magnetic (e.g., floppy disk, hard disk, magnetic tape), optical (e.g., high-density digital video disc (DVD)) or semiconductor (e.g., solid state disk (SSD)).

[00518] Those skilled in the art will appreciate that "first," "second," and other ordinal numerals used in the description of the present invention are for convenience of presentation only and do not limit the scope of embodiments of the present invention, but merely indicate the order of occurrence.

[00519] The term "at least one" in the present invention may also be interpreted as "one or more", and the term "plurality" may mean two, three, four or more, which is not limited to the present invention. In the embodiments of the present invention, the terms "first", "second" and "third", as well as the symbols "A", "B", "C" and "D" are used to denote various technical characteristics, while the description of the technical characteristics using the terms "first", "second" and "third", as well as the symbols "A", "B", "C" and "D" does not indicate any order of precedence or magnitude.

[00520] The correspondences presented in the tables of the present description can be configured or predetermined. The data values in the table are given only as an example and can be replaced by other values, which is not limited by the present invention. When configuring the correspondence between information and parameters, it is not necessary that all the correspondences given in the tables are configured. For example, the above tables can be adjusted accordingly, in particular, divided, combined and changed in other possible ways. Other terms acceptable for the communication device can be used for the names of the parameters given in the headings of the above tables, and the values or representations of the parameters can be replaced by other values or representations acceptable for the communication device. Each of the above tables can also be implemented using other data structures, such as arrays, queues, containers, stacks, linear tables, pointers, chained lists, trees, graphs, structures, classes, unordered arrays and hash tables.

[00521] The term "predetermined" as used herein may have the meaning of "determined," "predetermined," "stored," "pre-stored," "pre-agreed," "pre-configured," "corrected," or "pre-prepared."

[00522] Those skilled in the art will understand that the blocks and steps of the algorithm in each example described in the embodiments provided herein may be implemented as electronic hardware or as a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific applications and requirements for developing technical solutions. Those skilled in the art may use various methods to implement the described functions in each specific system, and such implementation should not be considered as going beyond the scope of the present invention.

[00523] It should be understood by those skilled in the art that, for convenience and brevity of presentation, the specific technological processes associated with the above-described systems, devices and units may be similar to the corresponding processes in the above-described embodiments of the method and will not be repeated here.

[00524] All of the above implementations are only specific embodiments of the invention and do not limit the scope of protection of the invention. It will not be difficult for specialists in this field of technology to propose changes or replacements within the framework of the solutions proposed by the invention, which will be included in the scope of the present invention. Therefore, the scope of the present invention is determined by the scope of the claims.

Claims (77)

1. A method for determining the hyperframe number (HFN) of a packet data convergence protocol (PDCP) entity, performed by a terminal device and comprising: receiving indication information transmitted by the network device, wherein the indication information includes HFN information; and determining the HFN value of a PDCP protocol object based on the HFN information; wherein the determination of the HFN value of the PDCP protocol object based on the HFN information includes: determining the HFN value of a PDCP protocol entity based on the HFN information when the applicable condition for the HFN information is met. 2. The method according to claim 1, wherein the HFN information includes at least one of an HFN value or a counter value (COUNT). 3. The method according to claim 1, which also includes receiving an applicable condition for the HFN information transmitted by the network device, or determining an applicable condition for the HFN information based on the accepted agreement; wherein the applicable condition for the HFN information includes either one of a sequence number (SN) value or a system frame number (SFN) value. 4. The method according to claim 3, wherein the SN value includes at least one of the following: minimum SN value; maximum SN value; minimum SN value and maximum SN value; section number corresponding to the SN value; or a pair of parameters (m, n) corresponding to the value of SN, where m is the number of sections after uniformly dividing all SN values into sections in a given order, and n is the number of the section containing the current value of SN, among all m sections, where n is an integer less than or equal to m; or the SFN value includes at least one of the following: minimum SFN value; maximum SFN value; minimum SFN value and maximum SFN value; the section number corresponding to the SFN value; or a pair of parameters (i, j) corresponding to the SFN value, where i is the number of sections after uniformly dividing all SFN values into sections in a given order, and j is the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i. 5. The method according to claim 3, wherein the fulfillment of the applicable condition includes at least one of the following: the SN value corresponding to the PDCP protocol data packet received by the terminal device satisfies the applicable condition; or the SFN value corresponding to the PDCP protocol data packet received by the terminal device satisfies the applicable condition; wherein the indication information further includes information about a multicast broadcast service (MBS), and the received PDCP protocol data packet is the first PDCP data packet received by the terminal device over an MBS radio channel (MRB) corresponding to the information about the MBS service; where the SFN value corresponding to the received PDCP protocol data packet includes any one of the following values: the SFN value corresponding to the time position of the last physical data channel on which a PCDP protocol data packet was successfully received; the SFN value corresponding to the time position of the first physical data channel on which a PCDP protocol data packet is successfully received; or SFN value corresponding to successful reception of a PDCP protocol data packet. 6. The method according to any one of paragraphs 3-5, wherein the applicable condition is an SN value, and determining the HFN value of the PDCP protocol entity based on the HFN information includes: in the event of non-fulfilment of the applicable condition and the difference s between the SN value corresponding to the PDCP protocol data packet received by the terminal device and the SN value corresponding to the applicable condition, generating updated HFN information by updating the HFN information based on the difference s; and determining the HFN value of the PDCP protocol entity based on the updated HFN information; or the applicable condition is the SFN value, and the determination of the HFN value of the PDCP protocol entity based on the HFN information includes: in the event of non-fulfilment of the applicable condition and the difference k between the SFN value corresponding to the PDCP data packet received by the terminal device and the SFN value corresponding to the applicable condition, generating updated HFN information by updating the HFN information based on the difference k; and determining the HFN value of the PDCP protocol object based on the updated HFN information. 7. The method according to any one of paragraphs 1-5, in which the indication information further includes a mode of updating the HFN information, and determining the HFN value of the PDCP protocol entity based on the HFN information includes: in the event of failure to meet the applicable condition, generating updated HFN information by updating the HFN information depending on the update mode; and determining the HFN value of the PDCP protocol entity based on the updated HFN information; or The update mode includes the update step size and the update direction. 8. The method according to claim 1, wherein receiving indication information transmitted by the network device includes at least one of the following: receiving indication information transmitted by a network device based on a system message; receiving indication information transmitted by a network device based on a message in a control channel of a multicast broadcast service (MBS); or receiving indication information transmitted by a network device based on a separate configuration message of the terminal device. 9. The method according to claim 1, wherein the indication information further includes information about a multicast broadcast service (MBS), and determining the HFN value of the PDCP protocol entity based on the HFN information includes: determining the HFN value of the PDCP protocol object corresponding to the MBS service information based on the HFN information, wherein the MBS service information includes at least one of the following: an MBS service identifier (ID), an MBS channel identifier, or MBS channel protocol object configuration information, wherein the method further includes decrypting or checking the integrity of the received data corresponding to the MBS service information based on the HFN information. 10. The method according to claim 1, wherein determining the HFN value of the PDCP protocol object based on the HFN information includes: determining the HFN value of the PDCP protocol object based on the HFN information when the terminal device starts accessing the multicast broadcast service (MBS). 11. A method for determining the hyperframe number (HFN) of a Packet Data Convergence Protocol (PDCP) entity, performed by a network device and comprising: transmitting indication information to the terminal device, wherein the indication information includes HFN information; and transmitting to the terminal device the applicable condition for the HFN information. 12. The method according to claim 11, wherein the HFN information includes at least one of an HFN value or a counter value (COUNT). 13. The method of claim 12, wherein the applicable condition for the HFN information includes any one of a sequence number (SN) value or a system frame number (SFN) value. 14. The method of claim 13, wherein the SN value includes at least one of the following: minimum SN value; maximum SN value; minimum SN value and maximum SN value; section number corresponding to the SN value; or a pair of parameters (m, n) corresponding to the value of SN, where m is the number of sections after uniformly dividing all SN values into sections in a given order, and n is the number of the section containing the current value of SN, among all m sections, where n is an integer less than or equal to m; or the SFN value includes at least one of the following: minimum SFN value; maximum SFN value; minimum SFN value and maximum SFN value; the section number corresponding to the SFN value; or a pair of parameters (i, j) corresponding to the SFN value, where i is the number of sections after uniformly dividing all SFN values into sections in a given order, and j is the number of the section containing the current SFN value among all i sections, where j is an integer less than or equal to i. 15. The method according to claim 11, wherein the indication information further includes information about a multicast broadcast service (MBS); wherein the MBS service information includes at least one of the following: an MBS service identifier (ID), an MBS channel identifier, or MBS channel protocol entity configuration information. 16. The method according to claim 11, wherein the indication information further includes a mode of updating the HFN information, wherein the updating mode includes a step size of updating and a direction of updating. 17. The method according to any one of paragraphs 11-16, in which the transmission of indication information to the terminal device includes at least one of the following: transmitting indication information to a terminal device based on a system message; transmitting indication information to a terminal device based on a message in a control channel of a multicast broadcast service (MBS); or transmitting indication information to a terminal device based on a separate configuration message of the terminal device; the method additionally includes: in the event of a change in information in the system message other than the HFN information, transmitting to the terminal device the first change indication information; or in the event of a change in information in the MBS control channel message other than the HFN information, transmitting to the terminal device a second change indication information. 18. A communication device comprising a processor and a memory, wherein the memory is configured to store computer instructions, and the processor is configured to execute the computer instructions stored in the memory to cause the device to perform the method of any one of claims 1-10 or the method of any one of claims 11-17. 19. A machine-readable information carrier on which instructions are stored, the execution of which carries out the method according to any of paragraphs 1–10 or the method according to any of paragraphs 11–17.