Communication methods, terminal equipment, and network equipment

Abstract

This application relates to a communication method, terminal equipment, and network equipment. The method includes determining whether to perform security updates and / or Layer 2 processing based on first scenario information when the terminal equipment performs a first handover to one or more candidate cells. Embodiments of this application allow for flexible control of security updates and / or Layer 2 processing based on scenario information during the handover process.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to communication methods, terminal devices, and network devices.

Background Art

[0002] Similar to the Long Term Evolution (LTE) system, the New Radio Access (NR) system supports the handover process of user equipment (UE) in the connected state. The reasons for handover are various. For example, a UE using network services moves from one cell to another cell, adjusts the radio transmission traffic load, activates operation and maintenance, or has equipment failures. To ensure communication continuity and service quality, the communication link between the user and the original cell can be transferred to the new cell, that is, the handover process can be executed.

Summary of the Invention

[0003] Embodiments of this application provide a communication method, a terminal device, and a network device that can flexibly control security updates and / or layer 2 processing in the handover process.

[0004] Embodiments of this application provide a communication method, the method including: When a terminal device needs to perform a first handover to one or more candidate cells, determining whether to perform security updates and / or layer 2 processing based on first scenario information.

[0005] Embodiments of this application provide a communication method, the method including: A network device transmitting a candidate cell configuration, the candidate cell configuration being used to assist the terminal device in performing the first handover.

[0006] Embodiments of the present application provide terminal equipment, said terminal equipment, If a first handover to one or more candidate cells needs to be performed, the system includes a processing unit configured to determine whether to perform security updates and / or Layer 2 processing based on first scenario information.

[0007] Embodiments of the present application provide network equipment, said network equipment, The system includes a first transmitting unit configured to transmit candidate cell configurations, which are used to assist terminal equipment in performing a first handover.

[0008] Embodiments of the present invention provide a terminal device comprising a processor and memory. The memory is configured to store computer programs, and the processor causes the terminal device to perform the above-described communication method by calling and executing the computer programs stored in the memory.

[0009] Embodiments of the present application provide a network device comprising a processor and memory. The memory is configured to store computer programs, and the processor causes the network device to perform the above-described communication method by calling and executing the computer programs stored in the memory.

[0010] The embodiment of the present invention provides a chip that realizes the above-described communication method.

[0011] Specifically, the chip includes a processor, and the processor calls and executes a computer program from memory, thereby causing the device on which the chip is installed to perform the above-described communication method.

[0012] An embodiment of the present invention provides a computer-readable storage medium in which a computer program is stored, and causes the device to execute the above-described communication method when the computer program is executed by the device.

[0013] Embodiments of the present invention provide a computer program product that includes computer program instructions, which cause a computer to execute the above-described communication method.

[0014] An embodiment of the present invention provides a computer program that, when executed on a computer, causes the computer to perform the above-described communication method.

[0015] According to the embodiment of the present invention, security updates and / or Layer 2 processing can be flexibly controlled in the handover process based on scenario information. For example, it is possible to ensure that terminal devices can support continuous handover, thereby ensuring service continuity, and to reduce signaling overhead caused by frequent security updates / Layer 2 processing. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram of the application scenario according to the embodiment of the present invention. [Figure 2] This is a schematic diagram of the cell handover process between base stations. [Figure 3] This is a schematic flowchart of a communication method according to one embodiment of the present invention. [Figure 4] This is a schematic flowchart of a communication method according to another embodiment of the present invention. [Figure 5] This is a schematic flowchart of a communication method according to another embodiment of the present invention. [Figure 6] This is a schematic flowchart of a communication method according to one embodiment of the present invention. [Figure 7] This is a schematic flowchart of a communication method according to another embodiment of the present invention. [Figure 8] This is a schematic block diagram of a terminal device according to one embodiment of the present invention. [Figure 9] This is a schematic block diagram of a terminal device according to another embodiment of the present invention. [Figure 10]This is a schematic block diagram of a network device according to an embodiment of the present application. [Figure 11] This is a schematic block diagram of a network device according to another embodiment of the present application. [Figure 12] This is a schematic block diagram of a communication device according to an embodiment of the present application. [Figure 13] This is a schematic block diagram of a chip according to an embodiment of the present application. [Figure 14] This is a schematic block diagram of a communication system according to an embodiment of the present application.

Mode for Carrying Out the Invention

[0017] Hereinafter, referring to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described.

[0018] The technical solutions in the embodiments of the present application can be applied to systems such as various communication systems, for example, Global System of Mobile communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA (registered trademark)) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, Advanced long term evolution (LTE-A) system, New Radio (NR) system, evolved system of the NR system, LTE-based access to unlicensed spectrum (LTE-U) system, NR-based access to unlicensed spectrum (NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (WiFi), 5th-Generation (5G) communication system or other communication systems.

[0019] Generally, conventional communication systems support a limited number of connections and are easy to implement. However, with the advancement of communication technology, mobile communication systems now support not only conventional communication but also, for example, D2D (Device to Device) communication, M2M (Machine to Machine) communication, Machine Type Communication (MTC), Vehicle to Vehicle (V2V) communication, and Vehicle to Everything (V2X) communication. The embodiment of this application is also applicable to these communication systems.

[0020] In one embodiment, the communication system in the embodiment of the present application may be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, or a standalone (SA) network deployment scenario.

[0021] In one embodiment, the communication system in the embodiment of the present application may be applied to an unlicensed spectrum, where the unlicensed spectrum may be a shared spectrum. Alternatively, the communication system in the embodiment of the present application may also be applied to a licensed spectrum, where the licensed spectrum may be a non-shared spectrum.

[0022] The embodiments of this application describe each embodiment in relation to network equipment and terminal equipment, and terminal equipment may be called user equipment (UE), access terminal, user unit, user station, mobile station, mobile site, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device.

[0023] Terminal devices may be stations (STs) in a WLAN, cellular phones, cordless phones, SIP (Session Initiation Protocol) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistant (PDA) devices, portable devices with wireless communication capabilities, computing devices, or other processing devices connected to wireless modems, in-vehicle devices, wearable devices, terminal devices in next-generation communication systems such as NR networks, or terminal devices in future advanced Public Land Mobile Networks (PLMNs).

[0024] In the embodiments of the present invention, the terminal equipment may be located indoors or outdoors, on land including handheld, wearable, or vehicle-mounted devices, on water (such as on a ship), or in the air (such as on an airplane, balloon, or satellite).

[0025] In the embodiments of this application, the terminal device may be a mobile phone, a tablet PC, a PC equipped with wireless transceiver functionality, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical care, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home.

[0026] As a non-limiting example, in the embodiments of this application, the terminal device may be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for wearable devices developed by applying wearable technology to intelligently design everyday clothing such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or incorporated into the user's clothing or accessories. Wearable devices are not merely hardware devices, but achieve powerful functionality through software support, data interaction, cloud interaction, etc. Wearable smart devices in a broad sense include devices such as smartwatches and smart glasses that are fully functional, large in size, and can achieve full or partial functionality without relying on a smartphone, as well as devices such as various smart bracelets and smart jewelry for monitoring physical condition that focus only on certain application functions and need to be used in conjunction with other devices such as smartphones.

[0027] In the embodiments of this application, the network equipment may be equipment that communicates with mobile devices, and the network equipment may be an access point (AP) in WLAN, a base transceiver station (BTS) in GSM or CDMA, a base station (NB) in WCDMA, an evolutionary base station (eNB or eNodeB) in LTE, or a relay station or access point, or a network device (gNB) in an in-vehicle device, wearable device and NR network, or a network device in a future advanced PLMN network or an NTN network, etc.

[0028] As an example that is not limiting, in the embodiments of the present application, the network equipment may have mobility characteristics, for example, the network equipment may be a mobile device. Optionally, the network equipment may be a satellite or a balloon station. For example, the satellite may be a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a geostationary Earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network equipment may be a base station located on land or in a body of water.

[0029] In the embodiments of the present invention, network equipment provides services to a cell, and terminal equipment communicates with the network equipment via transmission resources used by the cell (e.g., frequency domain resources or frequency spectrum resources), the cell may be a cell corresponding to network equipment (such as a base station), and the cell may belong to a macro base station or a base station corresponding to a small cell, where the small cell may include metro cells, micro cells, pico cells, and femto cells, and these small cells have the characteristics of low coverage and low transmission power and are applied to the provision of high-speed data transmission services.

[0030] Figure 1 illustrates a communication system 100. The communication system includes one network device 110 and two terminal devices 120. In one embodiment, the communication system 100 may include a plurality of network devices 110, and the coverage of each network device 110 may include another number of terminal devices 120, and the embodiments of the present application are not limited thereto.

[0031] In one embodiment, the communication system 100 may also include other network entities such as a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF), and the embodiments of the present application are not limited to these.

[0032] Here, network equipment may further include access network equipment and core network equipment. That is, the wireless communication system further includes multiple core networks for communicating with access network equipment. Access network equipment may be evolutionary base stations (eNB or e-NodeB), macro base stations, micro base stations (also called "small base stations"), pico base stations, access points (AP), transmission points (TP), or new generation base stations (gNodeB) in long-term evolution (LTE) systems, next-generation (NR) systems, or LAA-LTE (authorized auxiliary access long-term evolution) systems.

[0033] It should be understood that, in the embodiments of this application, devices with communication capabilities in a network / system may be referred to as communication devices. Taking the communication system shown in Figure 1 as an example, communication devices may include network devices and terminal devices with communication capabilities, and network devices and terminal devices may be specific devices in the embodiments of this application and will not be described again here. Communication devices may also include other devices in the communication system, such as other network entities such as network controllers and mobile management entities, but the embodiments of this application are not limited to these.

[0034] It should be understood that the terms “system” and “network” as used herein are always interchangeable. The terms “and / or” as used herein describe only the associated relationship and indicate that three relationships may exist; for example, A and / or B can represent three cases: A existing independently, both A and B existing, or B existing independently. The symbol “ / ” as used herein generally indicates that the relationship between the preceding and following associated objects is “or.”

[0035] Furthermore, it should be understood that the word "show" in the embodiments of this application may mean showing directly, showing indirectly, or showing in a related manner. For example, A showing B can mean that A directly shows B, for example, that B can obtain information through A; it can also mean that A indirectly shows B, for example, that A shows C and B can obtain information through C; or it can mean that A and B have a related relationship.

[0036] In the description of the embodiments of this application, the term "corresponding" can indicate that there is a direct or indirect corresponding relationship between the two, that there is a related relationship between the two, or that there is a relationship such as showing and being shown, or forming and being formed.

[0037] To facilitate understanding of the technical solutions in the embodiments of this application, related technologies of the embodiments are described below. These related technologies can be optionally combined with the technical solutions of the embodiments of this application as optional solutions, and are all included within the scope of protection of the embodiments of this application.

[0038] 1. Conventional handover process Figure 2 is a schematic diagram of the cell handover process between base stations, and an example of the handover process is shown below.

[0039] 1. The source base station triggers a handover based on Layer 3 (L3) measurement results reported by the terminal and sends a handover request to the target cell via the Xn interface.

[0040] 2. The target base station receives a handover request from the source base station and provides the Radio Resource Control (RRC) configuration for the target cell, which is then fed back to the source base station as part of the handover request acknowledgment.

[0041] 3. The source base station sends an RRC Reconfiguration to the UE to instruct it to start the handover process and transmits RRC configuration information for accessing the target cell.

[0042] 4. The UE accesses the target cell and sends an RRC Reconfiguration Complete message to the target cell.

[0043] Table 1 shows the main operations of each protocol layer (e.g., Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), and Media Access Control (MAC)) after the UE receives a handover command.

[0044] [Table 1]

[0045] Here, security updates may include key updates, encryption / integrity protection algorithms, etc., and may be explicitly indicated in the RRCReconfiguration message.

[0046] Whether or not to perform PDCP reconstruction, PDCP layer data recovery, and RLC reconstruction can be explicitly indicated in the RRCReconfiguration message.

[0047] The PDCP layer is primarily responsible for data encryption / decryption and integrity protection within the Access Stratum (AS) layer.

[0048] 2. Subsequent conditional primary / secondary cell addition or change (SCPAC) R16 and R17 each introduced a conditional primary / secondary cell addition / change (CPAC) process. The network configures one or more candidate cells and the condition information associated with those candidate cells for the UE. After receiving the configuration, the UE continuously evaluates the configured candidate cells. If one or more candidate cells meet the conditions, the UE triggers the CPAC process. After the UE completes the CPAC process, the UE releases all candidate cell configurations provided by the network.

[0049] To avoid frequent reconfiguration of CPAC configurations by the network, R18 further enhances the CPAC process to support UEs continuing to evaluate candidate cells and execute the next CPAC process without releasing the candidate cell configuration after completing a single conditional primary / secondary cell addition (CPA) or conditional primary / secondary cell change (CPC) process.

[0050] Both L1 or L2 triggered mobility (LTM) and SCPAC support sequential handovers. In the handover process, the UE only needs to perform a key update if the PDCP anchor changes. That is, a key update is required in inter-centralized unit (inter-CU) / inter-secondary node (inter-SN) scenarios. In related technologies, inter-centralized unit (inter / intra CU) and inter-secondary node (inter / intra SN) scenarios are invisible to the UE. The communication method of the embodiment of this application allows the UE to perform corresponding operations such as key updates and Layer 2 processing by instructing it on the current handover scenario.

[0051] Furthermore, if the network configures an SN identifier for each candidate cell in the candidate cell configuration, the UE can determine whether or not to perform a key update by comparing whether the SN identifiers associated with the source cell and the target cell are the same. The communication method provided in the embodiment of the present application may include a specific mechanism by which the UE determines whether or not to perform actions such as key updates and Layer 2 processing after the UE has handed over from a source cell to a candidate cell and after the UE has performed a network-triggered primary-secondary cell change (pscell change).

[0052] Figure 3 is a schematic flowchart of a communication method 300 according to one embodiment of the present invention. The method is optionally applicable to the system shown in Figure 1, but is not limited thereto. The method includes at least some of the following:

[0053] In step S310, if the terminal device needs to perform a first handover to one or more candidate cells, it decides whether to perform a security update and / or Layer 2 processing based on the first scenario information.

[0054] In the embodiments of this application, candidate cells may be pre-configured by network equipment or configured in terminal equipment. When certain handover conditions are met, terminal equipment may perform a single handover from a source cell to a single candidate cell, or it may perform a series of handovers from a source cell to multiple candidate cells. When a series of handovers from a source cell to multiple candidate cells is performed, each candidate cell that has been handed over can be considered to become the source cell in the next handover. For example, UE1 performs a series of handovers from source cell cell#0 to multiple candidate cells cell#1, cell#2, and cell#3. After UE1 has handed over from cell#0 to cell#1, it can then hand over cell#1 to cell#2 as the source cell. After UE1 has handed over from cell#1 to cell#2, it can then hand over cell#2 to cell#3 as the source cell.

[0055] In the embodiments of the present invention, the handover conditions may include a variety of conditions, such as the UE moving from one cell to another, the source cell channel quality degrading, the candidate cell quality improving, or the candidate cell channel quality being better than that of the source cell.

[0056] According to the embodiment of the present invention, security updates and / or Layer 2 processing can be flexibly controlled in the handover process based on scenario information. For example, it is possible to ensure that terminal devices can support continuous handover, thereby ensuring service continuity, and to reduce signaling overhead caused by frequent security updates / Layer 2 processing.

[0057] In the embodiments of this application, the source cell may be a source serving cell. One or more candidate cells may include a target cell to be handed over.

[0058] In one embodiment, the first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, L1 or L2 trigger mobility (LTM), sequential primary cell handover, sequential primary-secondary cell addition or change (SCPAC), conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover.

[0059] In one embodiment, the security update includes a key update. For example, the key update may include a network-based key.

[0060] In one embodiment, the Layer 2 processing includes rebuilding the Layer 2 protocol stack.

[0061] In one embodiment, the Layer 2 protocol stack reconstruction includes packet data convergence protocol (PDCP) reconstruction, PDCP data recovery, radio link control (RLC) reconstruction, and media access control (MAC) reset.

[0062] In embodiments of the present invention, the first scenario information may be scenario information related to a first handover. The first scenario information may also be called a trigger condition or execution condition, and may be used to determine whether or not to perform security updates and / or Layer 2 processing in the event of a first handover.

[0063] In one embodiment, the first scenario information is Security updates and / or Layer 2 processing should be performed with each handover. No security updates and / or Layer 2 processing will be performed. Location information of source cells and / or target cells, It includes at least one piece of information revealed by the network.

[0064] For example, if the first scenario information includes performing a key update and / or Layer 2 protocol stack reconstruction at each handover, the UE can perform the key update and / or Layer 2 protocol stack reconstruction at each handover (including each handover in a series of handovers).

[0065] In another example, if the first scenario information includes not performing any key updates and / or Layer 2 protocol stack reconstructions, the UE may choose not to perform key updates and / or Layer 2 protocol stack reconstructions at each handover (including each handover in a sequence of handovers).

[0066] In another example, if the first scenario information includes location information for the source cell and / or target cell, the UE can determine whether to perform a key update and / or Layer 2 protocol stack reconstruction based on the location information for the source cell and / or target cell.

[0067] In another example, if the first scenario information includes information indicated by the network, the UE can determine whether to perform a key update and / or Layer 2 protocol stack rebuild based on the information indicated by the network.

[0068] In one embodiment, the arrangement information of the source cell and / or target cell is as follows: The source cell placement information and the target cell placement information are different. The location information of the source cell and the location information of the target cell must be the same. This includes at least one of the following: the location information of the source cell and / or target cell is unclear.

[0069] For example, if the source cell's location information differs from the target cell's location information, the UE may determine that a key update and / or Layer 2 protocol stack reconstruction is necessary.

[0070] In another example, if the location information of the source cell and the target cell is unclear, the UE may determine that a key update and / or Layer 2 protocol stack reconstruction is necessary. In this case, the UE can first request the network to retrieve the location information of the source cell and / or target cell, and then perform the first handover operation.

[0071] In another example, if the source cell's location information and the target cell's location information are the same, the UE may determine that it does not need to perform a key update and / or Layer 2 protocol stack rebuild.

[0072] In one embodiment, the arrangement information of the source cell and the arrangement information of the target cell are different. The source cell and the target cell belong to different secondary nodes (SN: Secondary Nodes). The source cell and the target cell belong to different centralized units (CUs). This includes at least one of the following: the source cell and the target cell belong to different distributed units (DUs).

[0073] For example, if the SN information of the source cell and the SN information of the target cell are different, it can be indicated that the source cell and the target cell belong to different SNs, or that the handover between the source cell and the target cell is an inter-SN handover.

[0074] In another example, if the CU information of the source cell and the CU information of the target cell are different, it can indicate that the source cell and the target cell belong to different CUs, or that the handover between the source cell and the target cell is an inter-CU handover.

[0075] In another example, if the DU information of the source cell and the DU information of the target cell are different, it can indicate that the source cell and the target cell belong to different DUs, or that the handover between the source cell and the target cell is an inter-DU handover.

[0076] In one embodiment, the arrangement information of the source cell and the arrangement information of the target cell are the same. The source cell and the target cell belong to the same SN. The source cell and the target cell belong to the same CU. This includes at least one of the following: the source cell and the target cell belong to the same DU.

[0077] For example, if the SN information of the source cell and the SN information of the target cell are the same, it can indicate that the source cell and the target cell belong to the same SN, or that the handover between the source cell and the target cell is an intra-SN handover.

[0078] In another example, if the CU information of the source cell and the CU information of the target cell are the same, it can indicate that the source cell and the target cell belong to the same CU, or that the handover between the source cell and the target cell is an intra-CU handover.

[0079] In another example, if the DU information of a source cell and the DU information of a target cell are the same, it can indicate that the source cell and the target cell belong to the same DU, or that the handover between the source cell and the target cell is an intra-DU handover.

[0080] In one embodiment, the method for determining whether the arrangement information of the source cell and the arrangement information of the target cell are the same is: Whether the source cell and the target cell are configured with the same SN information, CU information, DU information, and at least one of the group index, This includes at least one of the following: whether the source cell and the target cell are configured in the same group.

[0081] For example, a group index may have a correspondence with SN information. If the source cell and target cell are configured with a group index, it can be determined that the source cell and target cell belong to the same group, or that the SN information of the source cell and target cell is the same.

[0082] In another example, the candidate cells comprised of a network include different candidate cell groups, each group containing multiple candidate cells, and multiple candidate cells within a single group are considered to belong to the same group, the same SN, the same CU, or the same DU. If the source cell and target cell belong to the same candidate cell group, it can be determined that the source cell and target cell are configured within the same group.

[0083] In another example, the group index may have a correspondence with the CU information. If the source cell and target cell are configured with a group index, it can be determined that the source cell and target cell belong to the same group, or that the CU information of the source cell and target cell is the same.

[0084] In another example, the group index may have a correspondence with the DU information. If the source cell and target cell are configured with a group index, it can be determined that the source cell and target cell belong to the same group, or that the DU information of the source cell and target cell is the same.

[0085] In one embodiment, the location information of the source cell and / or target cell is unclear. The SN to which the aforementioned source cell belongs is unclear. The numbering system (SN) to which the aforementioned target cell belongs is unclear. The CU to which the aforementioned source cell belongs is unclear. The CU to which the aforementioned target cell belongs is unclear. The DU to which the aforementioned source cell belongs is unclear. This includes at least one of the following: the DU to which the target cell belongs is unclear.

[0086] In the embodiments of the present invention, if a terminal device cannot determine the location information of a source cell and / or target cell from local pre-configuration information or configuration information from the network, such location information can be considered unclear or unknown.

[0087] In one embodiment, the information shown by the network is Security updates and / or Layer 2 processing explicitly indicated by the network, A handover type that corresponds to security updates and / or Layer 2 processing explicitly indicated by the network. This includes at least one of the security updates and / or Layer 2 processes that need to be performed during one or more handovers, implicitly indicated by the network.

[0088] In the embodiments of the present invention, a terminal device can receive information from a network device indicating whether or not to perform a security update and / or Layer 2 processing. The information may explicitly or implicitly indicate whether or not to perform a security update and / or Layer 2 processing.

[0089] In some examples, bits in the information may explicitly indicate whether or not to perform security updates and / or Layer 2 processing. One or more bits in the information may be used to indicate security updates and / or Layer 2 processing. One or more bits in the information may be used to indicate the handover type corresponding to security updates and / or Layer 2 processing. For example, in the information, if one bit is 0, it indicates that the handover type is an S / N handover, and if it is 1, it indicates that the handover type is an S / N handover. In another example, in the information, if one of two bits is 0, it indicates that the handover type is a CU handover, and if it is 1, it indicates that the handover type is an S / N handover, and if the other bit is 0, it indicates that the handover type is a DU handover, and if it is 1, it indicates that the handover type is an DU handover.

[0090] Figure 4 is a schematic flowchart of a communication method 400 according to another embodiment of the present application. This method may include one or more features of the above-described communication method. In one embodiment, the communication method further includes the following steps.

[0091] In step S410, the terminal device acquires a candidate cell configuration, which is used to assist the terminal device in performing a first handover.

[0092] In one embodiment, the candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters.

[0093] In embodiments of the present invention, terminal equipment can either obtain candidate cell configurations from pre-configuration information or receive candidate cell configurations from network equipment. If the candidate cell configuration includes a source cell and placement information for one or more candidate cells, the handover type can be determined by comparing whether the source cell is the same as the placement information for one or more candidate cells (or target cells), and whether a security update needs to be performed and / or whether a Layer 2 protocol stack rebuild needs to be performed.

[0094] In the embodiments of this application, security update parameters may differ for different scenarios. For example, in the SN scenario, security update parameters may include a secondary node key counter (SK counter). In the CU and / or DU scenarios, security update parameters may include a next hop chaining counter (NCC).

[0095] After step S410, step S310 can be executed. Based on the result of step S310, if a security update is required, step S420, described below, is executed.

[0096] In one embodiment, the communication method further includes the following steps.

[0097] In step S420, the terminal device performs a security update based on the one or more security update parameters.

[0098] In one embodiment, step S420, the terminal device performing a security update based on the one or more security update parameters includes at least one of the following methods.

[0099] Method 1: The terminal device randomly selects one of the one or more security update parameters and performs a security update. For example, if the candidate cell configuration includes N SK counters (where N is greater than 1) and the source cell's SN information differs from the target cell's SN information, the UE can select one of the N SK counters and perform a key update along with the network key. In another example, if the candidate cell configuration includes M NCCs (where M is greater than 1) and the source cell's CU information differs from the target cell's CU information, the UE can select one of the M NCCs after this handover and perform a key update along with the network key.

[0100] Method 2: The terminal device determines the target security update parameters from the one or more security update parameters in ascending or descending order, and performs a security update based on the target security update parameters. For example, if the candidate cell configuration contains N SK counters (where N is greater than 1), the order is SK1, SK2, and SK3. If the SN information of the source cell and the SN information of the target cell are different, the UE may first perform a key update with the network key using SK1 after the current handover, then perform a key update with the network key using SK2 after the next handover, and finally perform a key update with the network key using SK3 after the last handover. In another example, if the candidate cell configuration contains M NCCs (where M is greater than 1), the order is NCC1, NCC2, and NCC3. If the CU information of the source cell and the CU information of the target cell are different, the UE can first perform a key update with the network key using NCC1 after the current handover, then perform a key update with the network key using NCC2 after the next handover, and finally perform a key update with the network key using NCC3 after the last handover.

[0101] In one embodiment, performing the security update includes generating and / or updating a new key for a target cell based on the one or more security update parameters and network key. The new key may be used for encryption and / or integrity protection, and the new key may be one of the inputs to an encryption and / or integrity protection algorithm. For example, the network key may be pre-configured by a network device or configured on a terminal device. If a terminal device needs to perform a security update, such as a key update, after obtaining one or more security update parameters and a network key, it can input the security update parameters and network key into a predetermined algorithm to obtain a new key. An exemplary predetermined algorithm may be a Key Derivation Function (KDF).

[0102] In one embodiment, the placement information is SN information, the one or more security update parameters are one or more secondary node key counters (SK counters), and the network key is a master node (MN) key.

[0103] In one embodiment, the placement information is centralized unit (CU) information, the one or more security update parameters are one or more next-hop chaining counters (NCCs), and the network key is an MN key.

[0104] In one embodiment, the handover type corresponding to the execution of security updates and / or Layer 2 processing includes at least one of SN-to-SN handover, CU-to-CU handover, and DU-to-DU handover.

[0105] In one embodiment, security updates and / or Layer 2 processing may not be performed for at least one of the SN handovers, CU handovers, and DU handovers.

[0106] In one embodiment, the handover type is Information on the placement of candidate cells, Target cell placement information, It is determined based on at least one of the source cell placement information.

[0107] For example, if the SN information of the source cell and the SN information of the candidate cell are different, the handover type may be an inter-SN handover. If the SN information of the source cell and the SN information of the candidate cell are the same, the handover type may be an intra-SN handover. If the SN information of the source cell and the SN information of the target cell are different, the handover type may be an inter-SN handover. If the SN information of the source cell and the SN information of the target cell are the same, the handover type may be an intra-SN handover.

[0108] In another example, if the CU information of the source cell and the candidate cell are different, the handover type may be an inter-CU handover. If the CU information of the source cell and the candidate cell are the same, the handover type may be an intra-CU handover. If the CU information of the source cell and the target cell are different, the handover type may be an inter-CU handover. If the CU information of the source cell and the target cell are the same, the handover type may be an intra-CU handover.

[0109] In another example, if the DU information of the source cell and the candidate cell are different, the handover type may be an inter-DU handover. If the DU information of the source cell and the candidate cell are the same, the handover type may be an intra-DU handover. If the DU information of the source cell and the target cell are different, the handover type may be an inter-DU handover. If the DU information of the source cell and the target cell are the same, the handover type may be an intra-DU handover.

[0110] In one embodiment, the arrangement information of the candidate cells is Candidate cell configuration, Index of explicitly indicated placement information, Explicitly indicated group index, It is indicated by at least one of the implicitly indicated groupings of candidate cells.

[0111] In one embodiment, the placement information of the target cell is Candidate cell configuration, This is indicated by at least one of the handover instructions.

[0112] In one embodiment, the arrangement information of the source cell is Candidate cell configuration, This is indicated by at least one of the RRC reconfiguration messages.

[0113] Figure 5 is a schematic flowchart of a communication method 500 according to another embodiment of the present application. This method may include one or more features of the above-described communication method. In one embodiment, the communication method further includes the following steps.

[0114] In step S510, the terminal device receives a handover command, which includes information about the target cell and one or more security update parameters.

[0115] In one embodiment, the handover command is carried by a radio resource control (RRC) reconfiguration message.

[0116] In this embodiment, one or more security update parameters may be included in a handover instruction (also called a handover instruction, handover message, etc.) or in a candidate cell configuration. After obtaining one or more security update parameters, the UE can perform security updates as needed. For example, after step S510, step S310 can be performed, and if it is necessary to perform security updates based on the determination result of step S310, step S420 can be performed.

[0117] Figure 6 is a schematic flowchart of a communication method 600 according to one embodiment of the present invention. The method is optionally applicable to the system shown in Figure 1, but is not limited thereto. The method includes at least some of the following:

[0118] In step S610, the network device transmits a candidate cell configuration, which is used to assist the terminal device in performing a first handover.

[0119] In one embodiment, the candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters.

[0120] In one embodiment, the placement information is secondary node (SN) information, the one or more security update parameters are one or more secondary node key counters, and the network key is an MN key.

[0121] In one embodiment, the placement information is centralized unit (CU) information, the one or more security update parameters are one or more next-hop chaining counters (NCCs), and the network key is an MN key.

[0122] In one embodiment, the first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, LTM, sequential primary cell handover, SCPAC, conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover.

[0123] Figure 7 is a schematic flowchart of a communication method 700 according to another embodiment of the present application. This method may include one or more features of the above-described communication method. In one embodiment, the communication method further includes the following steps.

[0124] In step S710, the network device transmits a handover command, which includes information about the target cell and one or more security update parameters.

[0125] In one embodiment, the handover instruction is indicated by an RRC reconfiguration message.

[0126] For specific examples of methods 600 and 700 performed by the network equipment in this embodiment, refer to the descriptions related to network equipment such as base stations in methods 300, 400, and 500 above, and for brevity, do not repeat them here.

[0127] Example 1, SCPAC The network pre-configures one or more candidate cell configurations in the UE, which the UE uses to execute a continuous CPA / CPC process. The relationship between the candidate cells and the source serving cells can be inter-SN or intra-SN.

[0128] The network configures one or more secondary node key counters (SK counters) for each candidate cell or each SN, which are used for key updates, and the UE updates the key based on one or more SK counters when it is necessary to perform a key update.

[0129] 1. The conditions under which the UE needs to perform a key update include at least one of the following:

[0130] (1) Key updates must be performed with each handover.

[0131] (2) Do not perform any key updates, for example, do not update keys by default.

[0132] (3) When the source cell (e.g., source primary / secondary cell (Source pscell)) and the target cell (e.g., target primary / secondary cell (target pscell)) belong to different SNs. Here, the method by which the UE determines whether the two cells belong to the same SN may include determining whether they constitute the same SN / group index, or whether the two cells belong to the same group.

[0133] (4) When the source pscell and the target pscell belong to the same SN.

[0134] (5) When the serial number to which source pscell belongs is unknown.

[0135] (6) When the SN to which the target pscell belongs is unknown.

[0136] (7) When an explicit instruction to update the key is received from the network.

[0137] (8) When an explicit instruction is received from the network that the handover is an inter-SN handover.

[0138] (9) When the handover receives an implicit instruction from the network that it needs to perform a key update. For example, when the network instructs it to rebuild the PDCP, rebuild the RLC, etc.

[0139] 2. The method for determining whether the UE is currently in inter-SN handover or intra-SN handover includes at least one of the following:

[0140] (1) With respect to candidate cells, the configuration of the candidate cells may include SN information such as the SN information of the candidate cells. This information may be explicitly indicated by an SN index, a group index, etc., or it may be implicitly indicated by grouping the candidate cells.

[0141] (2) For a target cell, the pscell handover instruction may include the target cell's SN information. The pscell handover instruction may come from a serving cell (or source cell), and the source cell may be a serving cell that distributes candidate cell configurations, or it may be a target cell that subsequently successfully handed over.

[0142] (3) For source cells, the source cell's signal-to-noise information can be included in the RRC reconfiguration message.

[0143] 3. UE performing key updates based on one or more SK counters includes the following:

[0144] (1) The UE randomly selects one of one or more pre-configured SK counters to update the key.

[0145] (2) The UE determines a target SK counter from one or more pre-configured SK counters in ascending or descending order and updates the key.

[0146] The aforementioned handover includes, but is not limited to, conditional primary-secondary cell changes, primary-secondary cell changes, and subsequent primary-secondary cell changes.

[0147] Example 1-1: From CPA to a normal primary / secondary cell change, and then to CPC: If, after the UE has executed CPA, it receives a primary / secondary cell change (pscell change) command from the network side during the subsequent CPC candidate cell condition evaluation / monitoring process (where the target of the change is cell #1), the UE executes the primary / secondary cell change (pscell change) process based on the command and decides whether or not to update the key based on the SK counter information instruction contained in the pscell change command. For example, if the pscell change command contains an SK counter, the UE generates / updates the key based on the next-generation base station key (KgNB key: the next Generation Node B key) and the received SK counter. Here, the pscell change command may be an RRC reconfiguration message.

[0148] After the UE executes the pscell change (cell#1), if there is a candidate cell for a subsequent CPC that satisfies the execution conditions, for example, if the handover condition is met, the UE will execute a subsequent CPC execution (where the target of the change is cell#2). At this time, the UE decides whether or not to update the key based on the SN information of the candidate cell (cell#2) that satisfies the conditions and the SN information of the source serving cell (cell#1).

[0149] Here, the SN information of the candidate cell (cell#2) may be included in the candidate cell configuration. The SN information of the current source serving cell (cell#1) may be included in the pscell change instruction.

[0150] If the candidate cell (cell#2) and the source serving cell (cell#1) belong to the same SN, the UE does not need to perform the key update process; otherwise, the UE generates / updates the key based on the KgNB key and the selected SK counter.

[0151] Furthermore, there are also implicit methods. That is, When the UE receives a network instruction and hands over to cell#1, if it does not perform a key update, it means that cell#1 and the source cell (cell#0) have an intra-SN relationship. When the UE hands over to cell#2 via CPC, the UE only needs to compare whether cell#2 and cell#0 (the cell before handing over to cell#1) belong to the same SN. When the UE receives a network instruction and hands over to cell#1, if it performs a key update, the UE will always perform a key update when handing over to cell#2.

[0152] Example 1-2: From source primary / secondary cell (source pscell) to CPC: The UE receives multiple candidate cell configurations for a subsequent conditional primary-secondary cell change (SCPC) and evaluates / monitors the candidate cells based on the conditions configured by the network. If there are candidate cells that meet the conditions, the UE executes the CPC execution process. The UE decides whether or not to configure a key based on the SN (Signal Number) information of the candidate cells that meet the conditions and the SN information of the source serving cell.

[0153] Here, the SN information of the candidate cell may be included in the candidate cell configuration. The SN information of the current source serving cell may be included in the candidate cell configuration, or it may be instructed to the UE via explicit signaling (e.g., RRC or MAC control element (MAC CE)), or it may be included in the source cell configuration (e.g., RRC reconfiguration message).

[0154] If the candidate cell and the source serving cell belong to the same SN, the UE does not need to perform the key update process; otherwise, the UE generates / updates the key based on the KgNB key and the selected sk counter.

[0155] Optionally, in this case, if the source cell's SN information is not specified, the UE should perform a key update by default.

[0156] Optionally, if the source cell's signal-to-noise (SN) information is not provided, the UE may request the source cell to obtain the SN information before executing the CPC. For example, the UE may request the source cell to obtain the SN information via an RRC message or an uplink MAC CE.

[0157] Optionally, the UE determines whether the source cell is included in the candidate cell list. If it is, it decides whether to perform a key update based on the SN information of the candidate cell corresponding to the source cell. Optionally, when the network configures an SCPAC candidate configuration for the UE, it may also include instructional information that notifies the UE whether the source cell is configured as a candidate cell and / or the corresponding candidate cell index.

[0158] Example 2, LTM The network pre-configures one or more candidate cells in the UE, and the candidate cell configuration is used by the UE to execute a continuous LTM process. The relationship between the candidate cells and the source serving cells may be inter-CU or intra-CU, inter-DU or intra-DU.

[0159] LTM includes network-triggered LTM and UE-triggered LTM. Network-triggered LTM refers to the UE executing the handover process based on an LTM cell switch command delivered by the network. UE-triggered LTM refers to the UE triggering the handover process based on pre-configured conditions.

[0160] The network configures one or more next-hop chaining counters (NCCs) used for key updates for each candidate cell or each CU. The UE updates the key based on the one or more NCCs when it needs to perform a key update.

[0161] 1. The conditions under which the UE needs to perform a key update include at least one of the following:

[0162] (1) Key updates must be performed with each handover.

[0163] (2) Do not perform any key updates, for example, do not update keys by default.

[0164] (3) When the source cell and target cell belong to different CUs. Determining whether the two cells belong to the same CU may include determining whether they are configured in the same CU / group index, or whether the two cells are configured within the same group.

[0165] (4) When the source pcell and the target pcell belong to the same CU.

[0166] (5) When the CU to which the source pcell belongs is unknown.

[0167] (6) When the CU to which the target pcell belongs is unknown.

[0168] (7) When an explicit instruction for key update is received from the network. For example, an instruction to update the key, or a new NCC, or an instruction to the UE whether or not to use an NCC for the key update. In other words, an instruction to perform a horizontal key update or a vertical key update.

[0169] (8) When an explicit instruction is received from the network that the handover is an inter-CU handover.

[0170] (9) When the handover receives an implicit instruction from the network that it needs to perform a key update. For example, when the network instructs it to rebuild the PDCP, rebuild the RLC, reconfigure the MAC, etc.

[0171] 2. The method for determining whether the UE is currently in an inter-CU handover or an intra-CU handover includes at least one of the following:

[0172] (1) With respect to candidate cells, the candidate cell configuration may include CU indication information, which may be an explicit CU index, a group index, or implicitly indicated by grouping the candidate cells.

[0173] (2) For the target cell, CU information may be included in the pcell handover instruction.

[0174] (3) For source cells, CU information may be included in the RRC reconfiguration message.

[0175] 3. UE performing key updates based on one or more NCCs includes the following:

[0176] (1) The UE randomly selects one of the pre-configured NCCs and updates the key.

[0177] (2) The UE determines the target NCC from one or more pre-configured NCCs in ascending or descending order and updates the key.

[0178] (3) The UE performs a key update based on the NCC indicated by the handover instruction.

[0179] The aforementioned handover may include conditional pcell change, traditional pcell change, and subsequent pcell change, and the embodiments of this application are not limited thereto.

[0180] Example 2-1: Traditional primary / secondary cell change from LTM, and then back to LTM: If the UE receives a pcell change (cell#1) handover command from the network side during the subsequent LTM candidate cell condition evaluation / monitoring process after executing the LTM, the UE executes the pcell change handover process based on the command and decides whether or not to update the key based on the NCC information instruction contained in the pcell change command. For example, if the pcell change command contains an NCC, the UE generates / updates the key based on the KgNB key and the received NCC. Here, the pcell change handover command may also be an RRC reconfiguration message.

[0181] After the UE executes the pcell change (cell#1), if there are candidate cells for subsequent LTM that meet the execution conditions, the UE executes subsequent LTM execution (cell#2). At this time, the UE decides whether or not to update the key based on the CU instruction information of the candidate cell (cell#2) that meets the conditions and the CU information of the source serving cell (cell#1).

[0182] Here, the CU instruction information for the candidate cell (cell#2) is included in the candidate cell configuration. The CU information for the current source serving cell (cell#1) may also be included in the pcell change instruction.

[0183] If the candidate cell (cell#2) and the source serving cell (cell#1) belong to the same CU, the UE does not need to perform the key update process; otherwise, the UE generates / updates the key based on the KgNB key and the selected NCC.

[0184] Example 2-2: From source primary / secondary cell (source pscell) to LTM: The UE receives multiple candidate cell configurations for LTM and performs candidate cell evaluation / monitoring / measurement reporting based on the conditions or measurement configurations set by the network. If there are candidate cells that meet the conditions, the UE executes the LTM execution process. The UE decides whether or not to configure a key based on the CU instruction information of the candidate cells that meet the conditions and the CU information of the source serving cell.

[0185] Here, the CU instruction information for the candidate cell is included in the candidate cell configuration. The CU information for the current source serving cell may be included in the candidate cell configuration, or it may be instructed to the UE via explicit signaling (RRC or MAC CE), or it may be included in the source cell configuration (RRC reconfiguration message).

[0186] If the candidate cell and the source serving cell belong to the same CU, the UE does not need to perform the key update process; otherwise, the UE generates / updates the key based on the KgNB key and the selected NCC.

[0187] Optionally, in this case, if the source cell's CU information is not specified, the UE should perform a key update by default.

[0188] Optionally, if the source cell's CU information is not specified, the UE may request the source cell to obtain the CU information via an RRC message or uplink MAC CE before executing the LTM.

[0189] Optionally, if the LTM is a network-triggered LTM, the network side may include NCC or CU information in the LTM cell switch command so that the UE can update the key.

[0190] Example 3, also known as Layer 2 reset or Layer 2 protocol stack rebuild. Examples 1 and 2 primarily involve key updates in handover scenarios. In addition, in handover scenarios, the UE needs to perform L2 protocol stack resets, such as PDCP reconstruction, PDCP data recovery, RLC reconstruction, and MAC reconstruction (reset).

[0191] 1. Regarding the inter CU handover, since the keys need to be updated, the PDCP also needs to be rebuilt.

[0192] 2. Regarding the handover between intra-CU and inter-DU, since there is no need to update the keys, the PDCP does not need to be rebuilt. However, to ensure continuity of service, the PDCP needs to perform PDCP data recovery, RLC rebuilding, and MAC reset.

[0193] 3. Regarding intra-CU and intra-DU handovers, if the configuration of the source and target cells remains unchanged, the PDCP and RLC will not be rebuilt, and the MAC will not perform a full reset, but may perform a partial rebuild.

[0194] To support different L2 processing in the above scenarios, candidate cell configurations may include CU and / or DU instruction information. However, in some special scenarios, for example, the CU and / or DU information of the source cell may be unclear, and the CU and / or DU information of the target cell in a conventional handover may also be unclear (see the specific processing methods in Example 1 and / or Example 2).

[0195] 4.UE can perform an L2 reset if at least one of the following conditions is met:

[0196] (1) Perform an L2 reset after each handover.

[0197] (2) Do not perform any L2 resets, for example, do not perform L2 resets by default.

[0198] (3) When the source cell and target cell belong to different CU / DUs. Determining whether the two cells belong to the same CU / DU may include determining whether they are configured in the same CU / DU / group index or whether the two cells are configured within the same group.

[0199] (4) When the source pcell and the target pcell belong to the same CU / DU.

[0200] (5) When the CU / DU to which the source pcell belongs is unknown.

[0201] (6) When the CU / DU to which the target pcell belongs is unknown.

[0202] (8) When an L2 reset is explicitly instructed from the network.

[0203] (9) When the network receives explicit instructions that the handover is an inter-CU / DU handover.

[0204] This occurs when the network implicitly instructs the handover to perform an L2 reset. For example, if the network instructs a PDCP rebuild, RLC rebuild, MAC reconfiguration (or partial MAC reset), etc.

[0205] According to the solution provided in the embodiment of the present invention, even if a situation arises in which scenario information such as key updates is unknown during the process in which the UE performs a conditional handover, a normal handover, etc., operations such as key updates and / or Layer 2 protocol stack reconstruction can be performed.

[0206] Figure 8 is a schematic block diagram of a terminal device 800 according to one embodiment of the present invention. The terminal device 800 may include a processing unit 810. The processing unit 810 is configured to determine whether to perform security updates and / or Layer 2 processing based on the first scenario information when it is necessary to perform a first handover to one or more candidate cells.

[0207] In one embodiment, the security update includes a key update.

[0208] In one embodiment, the Layer 2 processing includes Layer 2 protocol stack reconstruction, and the Layer 2 protocol stack reconstruction includes PDCP reconstruction, PDCP data recovery, RLC reconstruction, and MAC reconstruction.

[0209] In one embodiment, the first scenario information is Security updates and / or Layer 2 processing should be performed with each handover. No security updates and / or Layer 2 processing will be performed. Location information of source cells and / or target cells, It includes at least one piece of information revealed by the network.

[0210] In one embodiment, the arrangement information of the source cell and / or target cell is as follows: The source cell placement information and the target cell placement information are different. The location information of the source cell and the location information of the target cell must be the same. This includes at least one of the following: the location information of the source cell and / or target cell is unclear.

[0211] In one embodiment, the arrangement information of the source cell and the arrangement information of the target cell are different. The source cell and the target cell belong to different secondary nodes (SNs). The source cell and the target cell belong to different centralized units (CUs). This includes at least one of the following: the source cell and the target cell belong to different distributed units (DUs).

[0212] In one embodiment, the arrangement information of the source cell and the arrangement information of the target cell are the same. The source cell and the target cell belong to the same SN. The source cell and the target cell belong to the same CU. This includes at least one of the following: the source cell and the target cell belong to the same DU.

[0213] In one embodiment, the method for determining whether the arrangement information of the source cell and the arrangement information of the target cell are the same is: Whether the source cell and the target cell are configured with the same SN information, CU information, DU information, and at least one of the group index, This includes at least one of the following: whether the source cell and the target cell are configured in the same group.

[0214] In one embodiment, the location information of the source cell and / or target cell is unclear. The SN to which the aforementioned source cell belongs is unclear. The numbering system (SN) to which the aforementioned target cell belongs is unclear. The CU to which the aforementioned source cell belongs is unclear. The CU to which the aforementioned target cell belongs is unclear. The DU to which the aforementioned source cell belongs is unclear. This includes at least one of the following: the DU to which the target cell belongs is unclear.

[0215] In one embodiment, the information shown by the network is Security updates and / or Layer 2 processing explicitly indicated by the network, A handover type that corresponds to security updates and / or Layer 2 processing explicitly indicated by the network. This includes at least one of the security updates and / or Layer 2 processes that need to be performed during one or more handovers, implicitly indicated by the network.

[0216] Figure 9 is a schematic block diagram of a terminal device 900 according to another embodiment of the present application. In one embodiment, the terminal device further comprises an acquisition unit 910. The acquisition unit 910 is configured to acquire candidate cell configurations, which are used to assist the terminal device in performing a first handover.

[0217] In one embodiment, the candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters.

[0218] In one embodiment, the processing unit 810 is configured to perform a security update based on the one or more security update parameters.

[0219] In one embodiment, the processing unit 810 is configured to randomly select one of the one or more security update parameters, perform a security update, determine a target security update parameter from the one or more security update parameters in ascending or descending order, and perform a security update based on the target security update parameter.

[0220] In one embodiment, performing the security update means that This includes generating and / or updating a new key for the target cell based on the aforementioned one or more security update parameters and network key.

[0221] In one embodiment, the placement information is secondary node (SN) information, the one or more security update parameters are one or more secondary node key counters, and the network key is an MN key.

[0222] In one embodiment, the placement information is centralized unit (CU) information, the one or more security update parameters are one or more NCCs, and the network key is an MN key.

[0223] In one embodiment, the first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, LTM, sequential primary cell handover, SCPAC, conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover.

[0224] In one embodiment, the handover type corresponding to the execution of security updates and / or Layer 2 processing includes at least one of SN-to-SN handover, CU-to-CU handover, and DU-to-DU handover.

[0225] In one embodiment, the handover type is Information on the placement of candidate cells, Target cell placement information, It is determined based on at least one of the source cell placement information.

[0226] In one embodiment, the arrangement information of the candidate cells is Candidate cell configuration, Index of explicitly indicated placement information, Explicitly indicated group index, It is indicated by at least one of the implicitly indicated groupings of candidate cells.

[0227] In one embodiment, the placement information of the target cell is Candidate cell configuration, This is indicated by at least one of the handover instructions.

[0228] In one embodiment, the arrangement information of the source cell is Candidate cell configuration, This is indicated by at least one of the RRC reconfiguration messages.

[0229] In one embodiment, as shown in Figure 9, the device further comprises a receiving unit 920, The receiving unit 920 is configured to receive a handover instruction, which includes information about the target cell and one or more security update parameters.

[0230] In one embodiment, the handover command is carried by a radio resource control (RRC) reconfiguration message.

[0231] The terminal devices 800 and 900 in the embodiments of this application can implement the corresponding functions of the terminal devices in the embodiments of the method described above. The corresponding processes, functions, implementation forms, and beneficial effects of each module (submodule, unit, or component, etc.) within the terminal devices 800 and 900 can be found in the corresponding descriptions in the embodiments of the method described above and will not be repeated here. The functions described for each module (submodule, unit, or component, etc.) within the terminal devices 800 and 900 in the embodiments of this application may be implemented by different modules (submodules, units, or components, etc.) or by the same module (submodule, unit, or component, etc.).

[0232] Figure 10 is a schematic block diagram of a network device 1000 according to one embodiment of the present invention. The network device 1000 may include a first transmission unit 1010. The first transmission unit 1010 is configured to transmit candidate cell configurations, which are used to assist terminal equipment in performing a first handover.

[0233] In one embodiment, the candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters.

[0234] In one embodiment, the placement information is secondary node (SN) information, the one or more security update parameters are one or more secondary node key counters, and the network key is an MN key.

[0235] In one embodiment, the placement information is centralized unit (CU) information, the one or more security update parameters are one or more next-hop chaining counters (NCCs), and the network key is an MN key.

[0236] In one embodiment, the first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, LTM, sequential primary cell handover, SCPAC, conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover.

[0237] Figure 11 is a schematic block diagram of a network device 1100 according to another embodiment of the present application. In one embodiment, the network device further comprises a second transmission unit 1110. The second transmission unit 1110 is configured to transmit a handover command, which includes information about the target cell and one or more security update parameters.

[0238] In one embodiment, the handover instruction is indicated by an RRC reconfiguration message.

[0239] The network devices 1000 and 1100 in the embodiments of this application can implement the corresponding functions of the network devices in the embodiments of the method described above. The corresponding processes, functions, implementation forms, and beneficial effects of each module (submodule, unit, or component, etc.) within the network devices 1000 and 1100 can be found in the corresponding descriptions in the embodiments of the method described above and will not be repeated here. The functions described for each module (submodule, unit, or component, etc.) within the network devices 1000 and 1100 in the embodiments of this application may be implemented by different modules (submodules, units, or components, etc.) or by the same module (submodule, unit, or component, etc.).

[0240] Figure 12 is a schematic block diagram of a communication device 1200 according to an embodiment of the present application. The communication device 1200 includes a processor 1210, and the processor 1210 can implement the method in the embodiment of the present application by calling and executing a computer program from memory.

[0241] In one embodiment, the communication device 1200 may further include a memory 1220, where the processor 1210 can call and execute a computer program from the memory 1220, thereby enabling the communication device 1200 to implement the method in the embodiment of the present application.

[0242] Here, the memory 1220 may be a separate device independent of the processor 1210, or it may be integrated into the processor 1210.

[0243] In one embodiment, the communication device 1200 may further include a transceiver 1230, and the processor 1210 can control the transceiver 1230 to communicate with other devices, specifically by transmitting information or data to other devices or receiving information or data transmitted from other devices.

[0244] Here, the transceiver 1230 may include a transmitter and a receiver. The transceiver 1230 may further include one or more antennas.

[0245] In one embodiment, the communication device 1200 may be a network device of the embodiment of the present application, and the communication device 1200 can implement the corresponding process implemented by the network device in each method of the embodiment of the present application, which will not be repeated here for brevity.

[0246] In one embodiment, the communication device 1200 may be a terminal device of the embodiment of the present application, and the communication device 1200 can realize the corresponding process realized by the terminal device in each method of the embodiment of the present application, which will not be repeated here for brevity.

[0247] Figure 13 is a schematic block diagram of a chip 1300 according to an embodiment of the present application. The chip 1300 includes a processor 1310, which can implement the method in the embodiment of the present application by calling and executing a computer program from memory.

[0248] In one embodiment, the chip 1300 may further include a memory 1320, where the processor 1310 can implement the method executed by the terminal or network equipment in the embodiment of the present application by calling and executing a computer program from the memory 1320.

[0249] Here, the memory 1320 may be a separate device independent of the processor 1310, or it may be integrated into the processor 1310.

[0250] In one embodiment, the chip 1300 may further include an input interface 1330. Here, the processor 1310 can control the input interface 1330 to communicate with other devices or chips, specifically, to acquire information or data transmitted from other devices or chips.

[0251] In one embodiment, the chip 130 may further include an output interface 1340. Here, the processor 1310 can control the output interface 1340 to communicate with other devices or chips, specifically, it can output information or data to other devices or chips.

[0252] In one embodiment, the chip may be applied to a network device of the embodiment of the present application, and the chip can implement the corresponding process implemented by the network device in each method of the embodiment of the present application, which will not be repeated here for brevity.

[0253] In one embodiment, the chip may be applied to a terminal device of the embodiment of the present application, and the chip can implement the corresponding process implemented by the terminal device in each method of the embodiment of the present application, which will not be repeated here for brevity.

[0254] The chips applied to network equipment and terminal equipment may be the same chip or different chips.

[0255] It should be understood that the chips referred to in the embodiments of this application may also be called system-level chips, system chips, chip systems, or system-on-a-chip.

[0256] The above-mentioned processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates, or transistor logic devices, discrete hardware components, etc. Here, the above-mentioned general-purpose processor may be a microprocessor or any conventional processor.

[0257] The above-mentioned memory may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Here, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM).

[0258] It should be understood that the above memory is exemplary but not limiting. For example, the memory in the embodiments of the present application may further be a static random access memory (SRAM), a dynamic random access memory (DRAM), a synchronous dynamic random access memory (SDRAM), a double data rate synchronous dynamic random access memory (DDR SDRAM), an enhanced synchronous dynamic random access memory (ESDRAM), a synchronous link dynamic random access memory (SLDRAM), a direct memory bus random access memory (DR RAM), etc. That is, the memory in the embodiments of the present application is intended to include these and any other suitable types of memory, but is not limited thereto.

[0259] FIG. 14 is a schematic block diagram of a communication system 1400 according to an embodiment of the present application. The communication system 1400 includes a terminal device 1410 and a network device 1420.

[0260] When the terminal device 1410 needs to perform a first handover to one or more candidate cells, it is configured to determine whether to perform security update and / or layer 2 processing based on the first scenario information.

[0261] The network device 1420 is configured to transmit a candidate cell configuration, and the candidate cell configuration is used to assist the terminal device in performing the first handover.

[0262] Here, the terminal device 1410 may be configured to implement the corresponding function realized by the terminal device in the above method, and the network device 1420 may be configured to implement the corresponding function realized by the network device in the above method, and for the sake of brevity, this will not be repeated here.

[0263] The embodiments described above can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded into a computer and executed, a process or function according to the embodiments of the present application is generated in whole or in part. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium and may be transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (infrared, radio, microwave, etc.). The computer-readable storage medium may be any available medium accessible to the computer, or it may be a data storage device such as a server or data center integrated by one or more available media. The aforementioned usable media may be magnetic media (floppy disks, hard disks, magnetic tapes, etc.), optical media (DVDs, etc.), or semiconductor media (solid-state hard disks (SSDs), etc.).

[0264] It should be understood that, in the various embodiments of the present application, the magnitude of the sequence numbers of the above processes does not indicate the execution order. The execution order of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0265] Those skilled in the art will clearly understand, for the sake of convenience and brevity of explanation, that the specific operating processes of the above-described systems, apparatuses and units can be described by referring to the corresponding processes in the embodiments of the methods described above, and will not be repeated here.

[0266] The above description is merely an embodiment of the present application, and the scope of protection of this application is not limited thereto. All modifications or substitutions that a person skilled in the art could easily conceive of within the technical scope disclosed herein should be included within the scope of protection of this application. Accordingly, the scope of protection of this application shall be subject to the scope of protection of the claims.

Claims

1. A method of communication, A communication method that includes determining whether to perform security updates and / or Layer 2 processing based on first scenario information when a terminal device needs to perform a first handover to one or more candidate cells.

2. The aforementioned security update includes key updates. The communication method according to claim 1.

3. The Layer 2 processing includes rebuilding the Layer 2 protocol stack, which includes rebuilding the Packet Data Convergence Protocol (PDCP), recovering PDCP data, rebuilding the Radio Link Control (RLC), and resetting the Media Access Control (MAC). The communication method according to claim 2.

4. The aforementioned first scenario information is, Perform security updates and / or Layer 2 processing with each handover. No security updates and / or Layer 2 processing will be performed. Location information of source cells and / or target cells, Includes at least one of the pieces of information revealed by the network, The communication method according to any one of claims 1 to 3.

5. The location information of the source cell and / or target cell is as follows: The source cell placement information and the target cell placement information are different. The location information of the source cell and the location information of the target cell must be the same. This includes at least one of the following: the location information of the source cell and / or target cell is unclear. The communication method according to claim 4.

6. The fact that the location information of the source cell and the location information of the target cell are different means that The source cell and the target cell belong to different secondary nodes (SNs). The source cell and the target cell belong to different centralized units (CUs). The source cell and the target cell belong to different distributed units (DUs), which is at least one of the following: The communication method according to claim 5.

7. The fact that the location information of the source cell and the location information of the target cell are the same means that The source cell and the target cell belong to the same SN. The source cell and the target cell belong to the same CU. The source cell and the target cell belong to the same DU, which is at least one of the following: The communication method according to claim 5 or 6.

8. The method for determining whether the location information of the source cell and the location information of the target cell are the same is: Whether the source cell and the target cell are configured with the same SN information, CU information, DU information, and at least one of the group index, The source cell and the target cell are configured in the same group, or at least one of the following: The communication method according to any one of claims 5 to 7.

9. The lack of clear information regarding the placement of the source cell and / or target cell means that The SN to which the aforementioned source cell belongs is unclear. The SN to which the aforementioned target cell belongs is unclear. The CU to which the aforementioned source cell belongs is unclear. The CU to which the aforementioned target cell belongs is unclear. The DU to which the aforementioned source cell belongs is unclear. This includes at least one of the following: the DU to which the target cell belongs is unclear. The communication method according to any one of claims 5 to 8.

10. The information shown by the aforementioned network is Security updates and / or Layer 2 processing explicitly indicated by the network, A handover type that corresponds to security updates and / or Layer 2 processing explicitly indicated by the network. This includes at least one of the security updates and / or Layer 2 processes that need to be performed in one or more handovers, implicitly indicated by the network. The communication method according to any one of claims 4 to 9.

11. The aforementioned communication method is, The terminal device further includes acquiring a candidate cell configuration, the candidate cell configuration being used to assist the terminal device in performing a first handover. The communication method according to any one of claims 1 to 10.

12. The candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters. The communication method according to claim 11.

13. The aforementioned communication method is, The terminal device further includes performing a security update based on the one or more security update parameters. The communication method according to claim 12.

14. The terminal device performs a security update based on the one or more security update parameters. The terminal device randomly selects one of the one or more security update parameters and performs a security update. The terminal device includes at least one of the following: determining a target security update parameter from one or more security update parameters in ascending or descending order, and performing a security update based on the target security update parameter. The communication method according to claim 13.

15. Performing the aforementioned security update means The process includes generating and / or updating a new key for a target cell based on one or more security update parameters and network keys. The communication method according to claim 13 or 14.

16. The aforementioned placement information is secondary node (SN) information, the one or more security update parameters are one or more secondary node key counters, and the network key is the master node (MN) key. The communication method according to any one of claims 12 to 15.

17. The aforementioned placement information is centralized unit (CU) information, the one or more security update parameters are one or more next-hop chaining counters (NCCs), and the network key is an MN key. The communication method according to any one of claims 12 to 15.

18. The first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, L1 or L2 trigger mobility (LTM), sequential primary cell handover, sequential primary-secondary cell addition or change (SCPAC), conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover. The communication method according to any one of claims 1 to 17.

19. The handover type corresponding to the execution of security updates and / or Layer 2 processing includes at least one of the following: inter-SN handover, inter-CU handover, and inter-DU handover. The communication method according to any one of claims 1 to 18.

20. The aforementioned handover type is, Information on the placement of candidate cells, Target cell placement information, Determined based on at least one of the source cell placement information, The communication method according to any one of claims 19.

21. The arrangement information of the candidate cells is, Candidate cell configuration, Index of explicitly indicated placement information, Explicitly indicated group index, Indicated by at least one of the implicitly indicated groupings of candidate cells, The communication method according to claim 20.

22. The placement information of the aforementioned target cell is Candidate cell configuration, Indicated by at least one of the handover instructions, The communication method according to claim 20 or 21.

23. The arrangement information of the aforementioned source cells is Candidate cell configuration, As indicated by at least one of the RRC reconstruction messages, A communication method according to any one of claims 20 to 22.

24. The aforementioned communication method is, The terminal device further includes receiving a handover command, the handover command including information about the target cell and one or more security update parameters. A communication method according to any one of claims 1 to 23.

25. The aforementioned handover instruction is carried by a radio resource control (RRC) reconfiguration message. The communication method according to claim 24.

26. A method of communication, The network device transmits a candidate cell configuration, which is used to assist a terminal device in performing a first handover.

27. The candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters. The communication method according to claim 26.

28. The aforementioned placement information is secondary node (SN) information, the one or more security update parameters are one or more secondary node key counters, and the network key is an MN key. The communication method according to claim 27.

29. The aforementioned placement information is central unit (CU) information, the one or more security update parameters are one or more next-hop chaining counters (NCCs), and the network key is an MN key. The communication method according to claim 27.

30. The first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, LTM, sequential primary cell handover, SCPAC, conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover. A communication method according to any one of claims 26 to 29.

31. The aforementioned communication method is, The network device further includes transmitting a handover command, the handover command including information about the target cell and one or more security update parameters. A communication method according to any one of claims 26 to 30.

32. The aforementioned handover instruction is indicated by the RRC reconfiguration message. The communication method according to claim 24.

33. Terminal device, A terminal device comprising a processing unit configured to determine whether to perform security updates and / or Layer 2 processing based on first scenario information when it is necessary to perform a first handover to one or more candidate cells.

34. The aforementioned security update includes key updates. The terminal device according to claim 33.

35. The Layer 2 processing includes Layer 2 protocol stack reconstruction, and the Layer 2 protocol stack reconstruction includes PDCP reconstruction, PDCP data recovery, RLC reconstruction, and MAC reconstruction. The terminal device according to claim 34.

36. The aforementioned first scenario information is, Perform security updates and / or Layer 2 processing with each handover. No security updates and / or Layer 2 processing will be performed. Location information of source cells and / or target cells, Includes at least one of the pieces of information revealed by the network, The terminal device according to any one of claims 33 to 35.

37. The location information of the source cell and / or target cell is as follows: The source cell placement information and the target cell placement information are different. The location information of the source cell and the location information of the target cell must be the same. This includes at least one of the following: the location information of the source cell and / or target cell is unclear. The terminal device according to claim 36.

38. The fact that the location information of the source cell and the location information of the target cell are different means that The source cell and the target cell belong to different secondary nodes (SNs). The source cell and the target cell belong to different centralized units (CUs). The source cell and the target cell belong to different distributed units (DUs), which is at least one of the following: The terminal device according to claim 37.

39. The fact that the location information of the source cell and the location information of the target cell are the same means that The source cell and the target cell belong to the same SN. The source cell and the target cell belong to the same CU. The source cell and the target cell belong to the same DU, which is at least one of the following: The terminal device according to claim 37 or 38.

40. The method for determining whether the location information of the source cell and the location information of the target cell are the same is: Whether the source cell and the target cell are configured with the same SN information, CU information, DU information, and at least one of the group index, The source cell and the target cell are configured in the same group, or at least one of the following: The terminal device according to any one of claims 37 to 39.

41. The lack of clear information regarding the placement of the source cell and / or target cell means that The SN to which the aforementioned source cell belongs is unclear. The SN to which the aforementioned target cell belongs is unclear. The CU to which the aforementioned source cell belongs is unclear. The CU to which the aforementioned target cell belongs is unclear. The DU to which the aforementioned source cell belongs is unclear. This includes at least one of the following: the DU to which the target cell belongs is unclear. A terminal device according to any one of claims 37 to 40.

42. The information shown by the aforementioned network is Security updates and / or Layer 2 processing explicitly indicated by the network, A handover type that corresponds to security updates and / or Layer 2 processing explicitly indicated by the network. This includes at least one of the security updates and / or Layer 2 processes that need to be performed in one or more handovers, implicitly indicated by the network. The terminal device according to any one of claims 36 to 41.

43. The aforementioned terminal device is The system further comprises an acquisition unit configured to acquire a candidate cell configuration, the candidate cell configuration being used to assist the terminal device in performing a first handover. The terminal device according to any one of claims 33 to 42.

44. The candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters. The terminal device according to claim 43.

45. The processing unit is configured to perform security updates based on the one or more security update parameters. The terminal device according to claim 44.

46. The processing unit is configured to randomly select one of the one or more security update parameters and perform a security update, determine a target security update parameter from the one or more security update parameters in ascending or descending order, and perform a security update based on the target security update parameter. The terminal device according to claim 45.

47. Performing the processing unit security update includes generating and / or updating a new key for the target cell based on the one or more security update parameters and network key. The terminal device according to claim 45 or 46.

48. The aforementioned placement information is secondary node (SN) information, the one or more security update parameters are one or more secondary node key counters, and the network key is the master node (MN) key. The terminal device according to any one of claims 44 to 47.

49. The aforementioned placement information is centralized unit (CU) information, the one or more security update parameters are one or more next-hop chaining counters (NCCs), and the network key is an MN key. The terminal device according to any one of claims 44 to 47.

50. The first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, L1 or L2 trigger mobility (LTM), sequential primary cell handover, sequential primary-secondary cell addition or change (SCPAC), conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover. A terminal device according to any one of claims 33 to 49.

51. The handover type corresponding to the execution of security updates and / or Layer 2 processing includes at least one of the following: inter-SN handover, inter-CU handover, and inter-DU handover. A terminal device according to any one of claims 33 to 50.

52. The aforementioned handover type is, Information on the placement of candidate cells, Target cell placement information, Determined based on at least one of the source cell placement information, The terminal device according to claim 51.

53. The arrangement information of the candidate cells is, Candidate cell configuration, Index of explicitly indicated placement information, Explicitly indicated group index, Indicated by at least one of the implicitly indicated groupings of candidate cells, The terminal device according to claim 52.

54. The placement information of the aforementioned target cell is Candidate cell configuration, Indicated by at least one of the handover instructions, The terminal device according to claim 52 or 53.

55. The arrangement information of the aforementioned source cells is Candidate cell configuration, As indicated by at least one of the RRC reconstruction messages, The terminal device according to any one of claims 52 to 54.

56. The aforementioned terminal device is The system further comprises a receiving unit configured to receive a handover instruction, the handover instruction including information about the target cell and one or more security update parameters. A terminal device according to any one of claims 33 to 55.

57. The aforementioned handover instruction is carried by a radio resource control (RRC) reconfiguration message. The terminal device according to claim 56.

58. Network equipment, A first transmission unit is configured to transmit candidate cell configurations, the candidate cell configurations being used to assist terminal equipment in performing a first handover.

59. The candidate cell configuration includes at least one of the following: placement information for one or more candidate cells, placement information for a source cell, and one or more security update parameters. The network device according to claim 58.

60. The aforementioned placement information is secondary node (SN) information, the one or more security update parameters are one or more secondary node key counters, and the network key is an MN key. The network device according to claim 59.

61. The aforementioned placement information is central unit (CU) information, the one or more security update parameters are one or more next-hop chaining counters (NCCs), and the network key is an MN key. The network device according to claim 59.

62. The first handover includes at least one of the following: conditional primary-secondary cell change, primary-secondary cell change, sequential primary-secondary cell change, LTM, sequential primary cell handover, SCPAC, conditional secondary cell change, primary-secondary cell change, primary cell change, and conditional primary cell handover. A network device according to any one of claims 58 to 61.

63. The aforementioned network equipment is The system further comprises a second transmission unit configured to send a handover command, the handover command including information about the target cell and one or more security update parameters. A network device according to any one of claims 58 to 62.

64. The aforementioned handover instruction is indicated by the RRC reconfiguration message. The network device according to claim 56.

65. A terminal device comprising a processor and memory, wherein the memory is configured to store computer programs, and the processor causes the terminal device to perform the method according to any one of claims 1 to 25 by calling and executing the computer programs stored in the memory.

66. A network device comprising a processor and memory, wherein the memory is configured to store computer programs, and the processor causes the network device to perform the method according to any one of claims 26 to 32 by calling and executing the computer programs stored in the memory.

67. A chip comprising a processor, wherein the processor calls and executes a computer program from memory, thereby causing a device on which the chip is mounted to perform the method according to any one of claims 1 to 25.

68. A computer-readable storage medium in which a computer program is stored, wherein when the computer program is executed by a device, the device is instructed to execute the method according to any one of claims 1 to 25 or any one of claims 26 to 32.

69. A computer program product comprising computer program instructions, wherein the computer program instructions cause a computer to execute the method described in any one of claims 1 to 25 or any one of claims 26 to 32.

70. A computer program that causes a computer to perform the method described in any one of claims 1 to 25 or any one of claims 26 to 32.

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