Cell handover method, network device and terminal device

Abstract

The present application provides a cell handover method, a network device and a terminal device, which are beneficial to reducing the frequency of signaling interaction and reducing signaling overhead when an NTN system performs cell handover. The method is applied to handover from a source cell corresponding to a source network device to a target cell corresponding to a target network device, and comprises: the source network device determines a first terminal device group among a first terminal device set that performs the cell handover, the first terminal device set comprising one or more first terminal device groups; and the source network device sends a first message group to the target network device, wherein the first message group is used for indicating handover requests of all terminal devices among the first terminal device group, and the first message group comprises first public information related to the source cell and / or the target cell and second public information related to terminal devices among the first terminal device group.

Description

Cell switching method, network device and terminal device Technical Field

[0001] The present application relates to the field of communication technology, and more specifically, to a cell switching method, network equipment, and terminal equipment. Background Art

[0002] Certain communication systems, such as non-terrestrial networks (NTNs), feature fast device mobility and wide cell coverage. During the cell handover process in such systems, a large number of devices switch simultaneously, leading to a sharp increase in signaling traffic between network devices and between network devices and devices, causing congestion.

[0003] Summary of the Invention

[0004] The present application provides a cell handover method, network device, and terminal device. The following introduces various aspects involved in the embodiments of the present application.

[0005] In a first aspect, a cell switching method is provided, which is applied to switching from a source cell corresponding to a source network device to a target cell corresponding to a target network device, including: the source network device determines a first terminal device group within a first terminal device set that performs the cell switching, and the first terminal device set includes one or more of the first terminal device groups; the source network device sends a first message group to the target network device, and the first message group is used to indicate a switching request for all terminal devices in the first terminal device group; wherein the first message group includes first public information related to the source cell and / or the target cell and second public information related to the terminal devices in the first terminal device group.

[0006] In a second aspect, a cell switching method is provided, which is applied to switching from a source cell corresponding to a source network device to a target cell corresponding to a target network device, including: the target network device receives a first message group sent by the source network device, the first message group is used to indicate a switching request for all terminal devices in a first terminal device group, the first terminal device group is any one terminal device group in a first terminal device set that performs the cell switching, and the first terminal device set includes one or more of the first terminal device groups; wherein the first message group includes first public information related to the source cell and / or the target cell and second public information related to the terminal devices in the first terminal device group.

[0007] According to a third aspect, a cell switching method is provided, which is applied to switching from a source cell corresponding to a source network device to a target cell corresponding to a target network device, including: a terminal device determines the first terminal device group in which it is located, the first terminal device group being any one of the first terminal device sets that performs the cell switching, and the first terminal device set including one or more of the first terminal device groups.

[0008] In a fourth aspect, a network device is provided, which is a source network device, and the source network device includes: a determination unit, used to determine a first terminal device group within a first terminal device set that performs cell switching, the first terminal device set including one or more of the first terminal device groups; a sending unit, used to send a first message group to a target network device, the first message group being used to indicate a switching request for all terminal devices in the first terminal device group; wherein the first message group includes first public information related to a source cell corresponding to the source network device and / or a target cell corresponding to the target network device, and second public information related to the terminal devices in the first terminal device group.

[0009] In a fifth aspect, a network device is provided, which is a target network device, and the target network device includes: a receiving unit for receiving a first message group sent by a source network device, the first message group being used to indicate a switching request for all terminal devices in a first terminal device group, the first terminal device group being any terminal device group in a first terminal device set that performs cell switching, the first terminal device set including one or more of the first terminal device groups; wherein the first message group includes first public information related to a source cell corresponding to the source network device and / or a target cell corresponding to the target network device, and second public information related to the terminal devices in the first terminal device group.

[0010] In the sixth aspect, a terminal device is provided, including: a determination unit, used to determine the first terminal device group to which the terminal device is located, the terminal device performing a cell switch from a source cell corresponding to a source network device to a target cell corresponding to a target network device, the first terminal device group being any one terminal device group in a first terminal device set that performs the cell switch, and the first terminal device set including one or more of the first terminal device groups.

[0011] In a seventh aspect, a communication device is provided, comprising a memory and a processor, wherein the memory is used to store a program, and the processor is used to call the program in the memory to execute the method described in any one of the first to third aspects.

[0012] In an eighth aspect, a device is provided, comprising a processor for calling a program from a memory to execute the method as described in any one of the first to third aspects.

[0013] In a ninth aspect, a chip is provided, comprising a processor for calling a program from a memory so that a device equipped with the chip executes the method described in any one of the first to third aspects.

[0014] In a tenth aspect, a computer-readable storage medium is provided, on which a program is stored, wherein the program enables a computer to execute the method as described in any one of the first to third aspects.

[0015] In an eleventh aspect, a computer program product is provided, comprising a program, wherein the program enables a computer to execute the method according to any one of the first to third aspects.

[0016] In a twelfth aspect, a computer program is provided, wherein the computer program enables a computer to execute the method as described in any one of the first to third aspects.

[0017] In the embodiment of the present application, the first terminal device group is determined based on two groupings performed by the source network device based on public information for handover requests at the cell level and the terminal device level, respectively. When performing a cell handover, the source network device can send handover requests for all terminal devices in the first terminal device group to the target terminal device in the form of a first message group. The first message group combines handover request information from multiple terminal devices based on public information at different levels, helping to avoid repeated transmission of the same information, reducing the frequency of signaling interactions between network devices, and reducing signaling overhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a wireless communication system used in an embodiment of the present application.

[0019] FIG2 is a schematic diagram of a scenario of a ground fixed cell applied in an embodiment of the present application.

[0020] FIG3 is a schematic diagram of a scenario of a ground mobile cell applied in an embodiment of the present application.

[0021] FIG4 is a schematic diagram of a feeder link switching scenario applied in an embodiment of the present application.

[0022] FIG5 is a cell switching process related to an embodiment of the present application.

[0023] FIG6 is a flow chart of a cell switching method provided in an embodiment of the present application.

[0024] FIG. 7 shows the information content included in the first message group in the method shown in FIG. 6 .

[0025] FIG8 is a schematic structural diagram of multiple possible implementations of the first sub-message of the first message group.

[0026] FIG9 is a schematic structural diagram of a possible implementation of the second sub-message of the first message group.

[0027] FIG10 is a schematic structural diagram of a possible implementation of the first message group.

[0028] FIG11 is a schematic structural diagram of another possible implementation of the first message group.

[0029] FIG12 is a schematic structural diagram of another possible implementation of the first message group.

[0030] FIG13 is a schematic diagram of a possible implementation of the method shown in FIG6 .

[0031] FIG14 shows the information content contained in the second message group.

[0032] FIG15 is a schematic structural diagram of various possible implementations of the first sub-message of the second message group.

[0033] FIG16 is a flowchart of another possible implementation of the method shown in FIG6 .

[0034] FIG17 is a flow chart of a possible implementation method for sending group information.

[0035] FIG18 is a flowchart illustrating another possible implementation of sending group information.

[0036] FIG19 is a flowchart illustrating another possible implementation of sending group information.

[0037] FIG20 is a flowchart illustrating another possible implementation of sending group information.

[0038] FIG21 is a comparison diagram of the embodiment of the present application and the related art.

[0039] Figure 22 is a structural diagram of a network device provided in an embodiment of the present application.

[0040] Figure 23 is a structural diagram of another network device provided in an embodiment of the present application.

[0041] Figure 24 is a structural diagram of the terminal device provided in an embodiment of the present application.

[0042] Figure 25 is a structural diagram of the communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The following will describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. With respect to the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0044] The embodiments of the present application can be applied to various communication systems. For example, the embodiments of the present application can be applied to global system of mobile communication (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, advanced long term evolution (LTE-A) system, new radio (NR) system, evolution system of NR system, LTE-based access to unlicensed spectrum (LTE-U) system on unlicensed spectrum, NR-based access to unlicensed spectrum (NR-U) system on unlicensed spectrum, NTN system, universal mobile telecommunication system (UMTS), wireless local area networks (WLAN), wireless fidelity (WiFi), and fifth generation communication (5th-generation, 5G) system. The embodiments of the present application can also be applied to other communication systems, such as future communication systems. The future communication system may be, for example, a sixth-generation (6G) mobile communication system or a satellite communication system.

[0045] Traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, communication systems can not only support traditional cellular communications, but also support one or more other types of communications. For example, a communication system can support one or more of the following communications: device to device (D2D) communication, machine to machine (M2M) communication, machine type communication (MTC), enhanced machine type communication (eMTC), vehicle to vehicle (V2V) communication, and vehicle to everything (V2X) communication, etc. The embodiments of the present application can also be applied to communication systems that support the above-mentioned communication methods.

[0046] The communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, and a standalone (SA) networking scenario.

[0047] The communication system in the embodiments of the present application can be applied to unlicensed spectrum. The unlicensed spectrum can also be considered a shared spectrum. Alternatively, the communication system in the embodiments of the present application can also be applied to licensed spectrum. The licensed spectrum can also be considered a dedicated spectrum.

[0048] The embodiments of the present application can be applied to terrestrial networks (TN) systems as well as NTN systems. As an example, the NTN system may include a 4G-based NTN system, an NR-based NTN system, an Internet of Things (IoT)-based NTN system, and a narrowband Internet of Things (NB-IoT)-based NTN system.

[0049] A communication system may include one or more terminal devices. The terminal devices mentioned in the embodiments of the present application may also be referred to as user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

[0050] In some embodiments, the terminal device may be a station (ST) in a WLAN. In some embodiments, the terminal device may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a next-generation communication system (e.g., a NR system), or a terminal device in a future-evolved public land mobile network (PLMN) network.

[0051] In some embodiments, a terminal device may be a device that provides voice and / or data connectivity to a user. For example, the terminal device may be a handheld device, an in-vehicle device, etc. with wireless connection capabilities. As some specific examples, the terminal device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc.

[0052] In some embodiments, the terminal device can be deployed on land. For example, the terminal device can be deployed indoors or outdoors. In some embodiments, the terminal device can be deployed on the water, such as on a ship. In some embodiments, the terminal device can be deployed in the air, such as on an airplane, a balloon, or a satellite.

[0053] In addition to the terminal device, the communication system may also include one or more network devices. The network device in the embodiment of the present application may be a device for communicating with the terminal device, and the network device may also be referred to as an access network device or a radio access network device. The network device may be, for example, a base station. The network device in the embodiment of the present application may refer to a radio access network (RAN) node (or device) that connects the terminal device to a wireless network. A base station can broadly cover various names as follows, or be replaced with the following names, such as: NodeB, evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmission point (TRP), transmission point (TP), master station MeNB, secondary station SeNB, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. A base station can also refer to a communication module, modem or chip used to be set in the aforementioned device or apparatus. The base station can also be a mobile switching center and a device that performs base station functions in D2D, V2X, and M2M communications, a network-side device in a 6G network, or a device that performs base station functions in future communication systems. The base station can support networks with the same or different access technologies. The embodiments of this application do not limit the specific technology and specific device form used by the network equipment.

[0054] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move based on the location of the mobile base station. In other examples, a helicopter or drone can be configured to act as a device that communicates with another base station.

[0055] In some deployments, the network device in the embodiments of the present application may refer to a CU or a DU, or the network device may include a CU and a DU. The gNB may also include an AAU.

[0056] By way of example and not limitation, in embodiments of the present application, a network device may be mobile, for example, a mobile device. In some embodiments of the present application, the network device may be a satellite or balloon station. In some embodiments of the present application, the network device may also be a base station located on land, water, or the like.

[0057] In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0058] For example, Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application. As shown in Figure 1, the communication system 100 may include a network device 110, which may be a device that communicates with a terminal device 120 (or also referred to as a communication terminal or terminal). The network device 110 may provide communication coverage for a specific geographic area and may communicate with terminal devices located within the coverage area.

[0059] Figure 1 exemplarily shows a network device and two terminal devices. In some embodiments of the present application, the communication system 100 may include multiple network devices and each network device may include other numbers of terminal devices within its coverage area, which is not limited in the embodiments of the present application.

[0060] In an embodiment of the present application, the wireless communication system shown in Figure 1 may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), but this embodiment of the present application does not limit this.

[0061] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system 100 shown in FIG1 as an example, the communication device may include a network device 110 and a terminal device 120 having a communication function. The network device 110 and the terminal device 120 may be the specific devices described above and will not be described in detail here. The communication device may also include other devices in the communication system 100, such as a network controller, a mobility management entity, and other network entities, which are not limited in the embodiments of the present application.

[0062] For ease of understanding, some relevant technical knowledge involved in the embodiments of this application is first introduced. The following related technologies can be combined with the technical solutions of the embodiments of this application as optional solutions, and they all fall within the scope of protection of the embodiments of this application. The embodiments of this application include at least part of the following contents.

[0063] With the development of communication technology, communication systems are gradually integrating satellite and terrestrial network infrastructure to realize market potential. For example, as 5G networks gradually become popular and saturated in cities, the aforementioned NTN has been introduced to improve 5G network utilization and coverage, enabling users and IoT devices in remote areas, deserts, and offshore regions to access 5G networks.

[0064] NTN utilizes non-terrestrial equipment such as satellites and high-altitude platforms to relay wireless signals. Compared to terrestrial cells, NTN can save costs and provide thin coverage in large, low-traffic areas. For example, satellites operate in high orbits, ranging from over 600 kilometers to 35,000 kilometers. Therefore, a single satellite can cover a large area of ​​the Earth's surface, allowing global coverage to be achieved with a small number of satellites.

[0065] In the NTN system, the cells projected by satellites onto the ground can be fixed relative to the ground or move with the satellite. Cells that are stationary relative to the ground are called quasi-Earth-fixed cells or ground-fixed cells. Cells that move with the satellite are called quasi-Earth-mobile cells or ground-mobile cells.

[0066] Regardless of the communication scenario, satellite communication systems have the characteristics of fast mobility, extended propagation time, and wide cell coverage. Traditional terrestrial mobile communication technology is difficult to adapt to satellite communication scenarios. Therefore, the 3rd Generation Partnership Project (3GPP) conducted protocol enhancement research for NTN based on the original 5G air interface in R17. Among the issues related to mobility enhancement, the focus is mainly on cell handover (HO), cell reselection, etc. Based on the problems and needs that may arise when terrestrial technology is applied to NTN, some protocol enhancement solutions were proposed in R17, but these solutions can only solve part of the problems. In R18, it is still necessary to study the mobility enhancement solutions for NTN. In the proposals related to NTN mobility enhancement, the current discussion points are focused on reducing and optimizing process signaling overhead.

[0067] The following schematically introduces the NTN cell handover scenario with reference to Figures 2 to 4. Figure 2 is a schematic diagram of a terrestrial fixed cell scenario, Figure 3 is a schematic diagram of a terrestrial mobile cell scenario, and Figure 4 is a schematic diagram of a feeder link handover scenario.

[0068] In a terrestrial fixed cell scenario, after the current satellite ends its service for a fixed cell, another nearby satellite takes over and provides service to all users within that cell. As shown in Figure 2, after satellite 210 ends its service for the fixed cell, satellite 220 will take over and provide service to all users within the cell. These users will need to switch their service satellite from satellite 210 to satellite 220.

[0069] In a terrestrial mobile cell scenario, since the coverage area of ​​a satellite cell moves with the satellite, users in different locations will leave the coverage of the source cell at different times and will switch to different (candidate) target satellites at different times. As shown in Figure 3, as satellite 310 moves, users in both area 302 and area 304 will need to perform a cell handover. Users in area 302 will switch to satellite 320, while users in area 304 will switch to satellite 330.

[0070] In an NTN system, the radio link between a satellite and a gateway (a gateway) is called a feeder link. In a feeder link handover scenario, as the satellite leaves the service range of the source gateway and gradually enters the service range of the destination gateway, it may trigger a switch in a user's serving base station. As shown in Figure 4, as satellite 410 moves along the direction indicated in Figure 4, it will leave the service range of gateway 430 and gradually enter the service range of gateway 440. In this case, the serving base station for all users within the satellite cell will switch from base station 420 to base station 450.

[0071] In an NTN system, due to the mobility of satellites, user handoffs are far more frequent than handoffs on the ground. Furthermore, due to the regularity of satellite motion, users often switch to the same satellite in groups. For example, in the terrestrial fixed cell shown in Figure 2, users in a cell served by a departing satellite 210 will simultaneously switch to the approaching satellite 220 when satellite 210 ends its service. For another example, in the terrestrial mobile cell shown in Figure 3, a group of geographically close users at the edge of the service area will likely switch to the same satellite. For another example, in the feeder link handoff shown in Figure 4, because satellite 410 is beyond the service range of the original gateway, users in the cell need to perform feeder link handoffs simultaneously.

[0072] Cell handover primarily occurs when a terminal device is in the Radio Resource Control (RRC) Connected state, enabling it to switch from its current serving cell to a target cell due to mobility. Generally speaking, cell handover technology primarily applies to users in the RRC Connected state, but the handover is primarily handled by the network. In terrestrial networks, 3GPP has established comprehensive technical standards for user handover procedures.

[0073] The handover process involves three phases: handover preparation, handover execution, and handover completion. According to relevant technical standards, during the handover preparation phase, the source base station (e.g., source gNB) and the target base station (e.g., target gNB) perform signaling exchanges and exchange terminal handover requests and responses. These exchanges must be sent to each terminal device, performing the handover preparation and response processes one by one. For ease of understanding, the following, combined with Figure 5, illustrates the interaction process during the handover preparation phase, using the example of a UE performing a cell handover.

[0074] 5 , the handover preparation phase 502 includes initial data transmission and steps S510 to S560 . In the initial stage of the cell handover preparation phase, user data is transmitted between the UE and the source base station, and between the source base station and user plane functions (UPF(s)).

[0075] In step S510, the AMF provides mobility control information to the source base station and the target base station.

[0076] In step S520, measurement control and reports of cell handover are transmitted between the UE and the source base station.

[0077] In step S530, the source base station makes a handover decision.

[0078] In step S540, the source base station sends a handover request to the target base station.

[0079] In step S550, the target base station performs admission control. Admission control generally has two purposes: determining the eligibility of the UE to access the target cell and reserving some resources for the UE on the target base station side according to the UE configuration.

[0080] In step S560, the target base station sends a handover request acknowledgement to the source base station.

[0081] In step S570, the source base station and the UE perform radio access network (RAN) handover initiation.

[0082] The signaling interaction and admission control approach shown in Figure 5 is suitable for terrestrial networks, where handoffs are driven by terminal device mobility and are relatively infrequent. However, in NTN systems, continuing to use the approach shown in Figure 5 would incur significant signaling overhead between base stations and between base stations and users, leading to congestion. As shown in Figures 2 through 4, in several cell handoff scenarios in NTN systems, satellite motion can cause a large number of users within a cell to switch cells. Due to the high speed of satellites, these numerous cell handoffs are frequent and unavoidable. If handoff preparation is performed on a per-user basis, the frequency of signaling interactions would be high.

[0083] It should be noted that the problem mentioned above that the NTN system, based on satellite mobility, leads to huge signaling overhead and high signaling interaction frequency in the cell switching preparation stage is only an example. The embodiments of the present application can be applied to any type of communication scenario in which the mobility of network equipment leads to a sharp increase in cell switching signaling.

[0084] To address the above issues, an embodiment of the present application proposes a cell handover method. Based on information sharing and multi-user message merging, this method optimizes the relevant handover process to reduce signaling overhead and interaction frequency. This method is applicable to the two major NTN satellite mobile network scenarios proposed by 3GPP, as well as the feeder link handover scenario. A detailed description of one of the methods in this embodiment is provided below, in conjunction with Figure 6.

[0085] Figure 6 describes a cell handover method from the perspective of interaction between a source network device, a target network device, and a terminal device. This cell handover method applies to handover from a source cell corresponding to a source network device to a target cell corresponding to a target network device. Dashed lines indicate optional execution of the process or timing of the execution of the process.

[0086] The terminal device is any of the terminal devices described above. In some embodiments, the terminal device is a communication device that provides services to satellites in an NTN system. In some embodiments, the terminal device is a communication device with a low service transmission rate. For example, the terminal device is an Internet of Things device.

[0087] The source network device is a communication device currently providing services to the terminal device. In some embodiments, the source network device may be a base station providing services to the terminal device via a satellite in an NTN system. In some embodiments, the source network device may be a non-satellite mobile network device. For example, the source network device may be a base station installed on a low-altitude aircraft.

[0088] The target network device is the network device that provides services to the terminal device after the source network device stops providing services to the terminal device. In some embodiments, the source network device can independently determine the target network device. For example, in the cell handover process of the NTN system, the source network device can determine the target network device corresponding to the terminal device without requiring a measurement report from the terminal device.

[0089] Typically, the target network device is a network device whose motion trajectory can be predicted. For example, the target network device may be a satellite in an NTN system. The source network device may determine the target network device providing services to the terminal device based on the ephemeris information. In another example, the target network device may be a non-satellite mobile network device. The source network device may determine the target network device providing services to the terminal device based on pre-set parameters.

[0090] In some embodiments, after determining the target network device, the source network device sends a handover preparation to the target network device. After receiving the handover response sent by the target network device, the source network device sends a handover initiation command to the terminal device.

[0091] 6 , in step S610 , the source network device determines a first terminal device group within a first terminal device set that performs cell handover.

[0092] Cell switching is the switching from the source cell corresponding to the source network device to the target cell corresponding to the target network device as described above. In some embodiments, a terminal device in the source cell with the target cell as the switching target can switch the serving cell from the source cell to the target cell by executing the cell switching process.

[0093] In some embodiments, the source network device may perform handover prediction and grouping for terminal devices performing cell handover during the handover decision phase in FIG5 , thereby determining a first terminal device group. For example, the source network device may predict the handover target and corresponding handover time for each terminal device. In another example, the source network device may group terminal devices that (potentially) switch to the same target network device at the same time into a single group based on the handover prediction results for the terminal devices.

[0094] For example, in an NTN system, the source network device may make a handover prediction / decision based on information such as the movement trajectory of the serving satellite and the adjacent satellites and the location of the terminal device.

[0095] Exemplarily, the source network device may have the capability of making advance handover predictions for the terminal devices and may group the terminal devices according to the handover prediction results.

[0096] The first terminal device set can be a set of terminal devices within the source cell that switch to the target cell at the same time. Because the target cell is the same, the terminal devices within this set can share source / target cell information. This information related to the source / target cell can be referred to as first common information. In other words, the source network device can group terminal devices based on the characteristics of the NTN handover interaction scenario, allowing the terminal devices within the set to share some handover request information.

[0097] The source network device can divide the terminal devices in the source cell according to the target cell corresponding to the terminal device and / or the time when the terminal device performs cell switching. For example, terminal devices with the same target cell can be divided into the same set. For another example, terminal devices that switch to the same target cell at the same time belong to a terminal device set. For another example, terminal devices that switch to the same target cell at adjacent times belong to the same set. Among them, adjacent time refers to the time when the same switching window can be shared. For another example, terminal devices that perform cell switching at different times belong to different terminal device sets. For another example, in an NTN network, terminal devices that switch to the same target satellite at the same time can be divided into the same set.

[0098] For example, the source network device may also divide the terminal device set according to different criteria based on actual conditions. For example, in grouping in a terrestrial mobile cell scenario, the source network device may use the actual geographic location of the terminal device as a criterion for diversity. In another example, in grouping in a terrestrial fixed cell scenario, the source network device may use the distance between the terminal device and the cell center as a criterion for diversity.

[0099] In some embodiments, the source cell may include one or more terminal device sets. For example, the terminal devices in the fixed cell shown in Figure 2 will all switch to satellite 220 at the same time, and these terminal devices belong to the same set. For another example, depending on the target cell, the terminal devices in area 302 in Figure 3 belong to one terminal device set, while the terminal devices in area 304 belong to another terminal device set.

[0100] The first terminal device group may be a collection of terminal devices within the first terminal device set that have the same handover request information. This identical information related to the terminal devices may be referred to as second common information. Because these terminal devices contain the same information, they can share not only the shared information about the cell of the first terminal device set but also user-level information.

[0101] By grouping the first terminal device set and the first terminal device group twice, cell-level and user-level information shared by multiple terminal devices can be obtained. This information can be used as common information when the source network device and the target network device exchange handover requests and responses for multiple terminal devices, and only needs to be transmitted once, thus reducing signaling overhead.

[0102] The first terminal device set may include one or more terminal device groups. The first terminal device group may be any terminal device group within the first terminal device set.

[0103] In some embodiments, one or more first terminal device groups in the first terminal device set can be determined based on one or more of the following information: the geographical location of the terminal device; the radio frequency range supported by the terminal device; the type of the terminal device; and the ability of the terminal device to access different access networks.

[0104] As an embodiment, terminal devices with adjacent geographical locations or similar radio frequency capabilities may share certain configurations in the radio resource management (RRM) measurement report. For example, these configurations can be used to indicate cell measurement results, such as reference signal received power (RSRP), reference signal strength indication (RSSI), etc. For another example, terminal devices that are geographically close may have the same candidate measurement cell configuration in the RMM measurement configuration. It should be noted that the network device should be aware of the relevant configuration information of the terminal device, so it can be directly regrouped according to the terminal device configuration information. The "terminal devices that are geographically close may have the same candidate measurement cell configuration in the RMM measurement configuration" is the reason why the terminal devices have the same configuration information rather than the grouping standard.

[0105] As an embodiment, terminal devices of the same or similar type have similar wireless network access capabilities. For example, smartphones or IoT devices have similar capabilities in supporting radio access technologies (RATs).

[0106] In summary, based on the handover prediction results for terminal devices, the source network device can group terminal devices that (likely) handover to the same target network device within the same (nearly) time period into a terminal device set. All terminal devices within this set share the target network device's information. Furthermore, the terminal devices within this set are regrouped. The main purpose of this regrouping is to group terminal devices with the same user-level parameter configuration into the same group whenever possible, so that terminal devices within the same group share not only cell-level information but also some user-level information.

[0107] To identify each terminal device group obtained from the two groupings, the source network device can assign the same group identity (ID) to the terminal devices belonging to the same terminal device group. This group ID should be unique within the source cell so that it can be combined with the source cell ID to globally index a unique terminal device group.

[0108] In step S620 , the source network device sends a first message group to the target network device.

[0109] The first message group is used to indicate the handover request of all terminal devices in the first terminal device group, and may also be referred to as a group handover request message group (GroupHandoverRequest message group, or GroupHOReq message group for short). In some embodiments, the source network device may generate the corresponding first message group based on the user's configuration information, source cell information, etc.

[0110] The first message group can include handover request information for all devices in the first group. Due to size limitations, a single message typically cannot contain information for all devices in the first group. Therefore, multiple sub-messages can be used to carry handover preparation information for devices in the same group, forming a message group. As previously mentioned, information that can be shared by devices only needs to be sent once, allowing the handover request signaling format to be restructured. This grouping and signaling format restructuring can reduce the signaling overhead incurred during the handover preparation phase in the NTN satellite network.

[0111] The first message group may include identification information of the first terminal device group (eg, group ID) to facilitate indexing.

[0112] The first message group may include first public information related to the source cell and / or target cell and second public information related to the terminal device. The first public information may also be referred to as cell-level information or basic public information, and the second public information may also be referred to as user-level information or optional public information.

[0113] In some embodiments, the first public information includes basic shared information between terminal devices in the same group. For example, the first public information may include cell-level shared information and basic message attribute information. The cell-level shared information includes at least cell identification information (e.g., cell ID or source network device ID), and basic message attributes such as message type, handover reason, and common timing advance (TA) configuration.

[0114] As an example, the message element (IE) of the first public information can be seen in Table 2 below.

[0115] In some embodiments, the second public information may include optional shared information between terminal devices in the same group, i.e., information that may be shared between terminal devices in addition to cell information and basic message attribute information. The specific content of this public information varies depending on the actual situation, and terminal devices in different situations may share different information.

[0116] As an example, the message elements in the second public information may refer to Table 3 below.

[0117] The first message group may also include exclusive information for all terminal devices in the first terminal device group. Exclusive information is user-level information specific to a terminal device, also known as exclusive information. Exclusive information can be used by the target network device to determine the handover request for each terminal device. For example, the target network device may determine the cell handover request information corresponding to each terminal device by combining the first public information, the second public information, and the exclusive information.

[0118] In some embodiments, exclusive information refers to terminal device identification and information that cannot be shared between terminal devices, such as security information, user session lists, etc. The terminal device identification is, for example, a cell radio network temporary identifier (C-RNTI). The user session list is, for example, protocol data unit (PDU) session related information. Security information is, for example, security key information (key gNB, KgNB) on the source base station side. Exclusive information is also, for example, mapping rules for quality of service (QoS) flows to data radio bearers (DRBs).

[0119] In some embodiments, for user-level information that cannot be shared between terminal devices, the existing data structure can be used to minimize the impact on relevant technical standards. However, the data structure must clear all IEs already included in the public information (including the first public information at the cell level and the second public information at the user level) in each user-level information segment.

[0120] As can be seen above, the source network device can send all request information for switching to the target network device to the target network device via the first message group for handover preparation. The first message group can be used to carry the information necessary for the terminal device to perform a handover between the source and target network devices. Therefore, the first message group mainly includes three parts: group ID, public information (public information includes first public information and second public information), and specific information for each terminal device.

[0121] Figure 7 is an example of the information content included in the first message group. The generation process of the first message group is exemplified with reference to the information content in Figure 7. Before generating the first message group, the two grouping steps mentioned above need to be performed first.

[0122] First, all terminal devices that are connected to the same target network device at the same time (nearby time) are grouped together. All terminal devices in this group share the cell-level common information and the information field indicating the message attributes, which corresponds to the basic common HO request information (first common information) field in Figure 7. The cell-level common information corresponds to the common cell configuration information (common cell config) field, which includes the source cell ID and other cell information; the indication message attributes correspond to the common HO request message attributes (common HO request message IEs) field.

[0123] Next, the terminal devices within the set are further grouped, with those with the same user-level information (non-cell information and non-message attribute information) grouped together. The user-level common information obtained through regrouping should be populated in the optional common HO request information (second common information) field shown in Figure 7. The group ID is used to indicate the user's grouping information in the regrouping.

[0124] Finally, the first message group must also carry terminal device-specific information, corresponding to the special HO request information (IEs) field shown in Figure 7. It should be noted that the terminal device-specific information must at least include each terminal device ID, so that the target network device can determine the group to which each terminal device belongs based on the user ID, source cell ID, and group ID. For example, the terminal device ID is User 1, User 2, etc. in Figure 7.

[0125] As shown in Figure 7, the information categories within the first message group include the group ID, first public information, second public information, and terminal device-specific information (unique user-level information). Based on the message size limit, the first message group can include one or more sub-messages. The size and content of each sub-message can be designed according to needs.

[0126] In some embodiments, the size of each sub-message does not exceed a preset message size to meet transmission requirements. For example, the number of terminal device information carried in each sub-message is determined based on factors such as network device performance, message rate, and expected processing latency. For example, each sub-message may carry M terminal device information, where M is a natural number greater than or equal to 1. M depends on the specific size limit of the message.

[0127] In some embodiments, the first message group includes at least one sub-message. Each sub-message includes first identification information corresponding to the first terminal device group and second identification information corresponding to the source cell, so that the target network device can identify all sub-messages corresponding to the first terminal device group. For example, each sub-message includes at least a group ID and its source network device ID. In another example, each sub-message includes at least a group ID and a source cell ID.

[0128] For ease of distinction, the first sub-message sent preferentially in the first message group may be referred to as the first sub-message, and any sub-message sent after the first sub-message may be referred to as the second sub-message.

[0129] In some embodiments, the first sub-message may carry information shared among the group of terminal devices, so that when the target network device receives the terminal device-specific information, it can combine it with the previously received public information to generate complete user handover preparation information. The shared information includes two parts: first public information (basic public information at the cell level) and second public information (optional public information at the user level). In other words, the first sub-message includes the first public information and the second public information.

[0130] In some embodiments, because the first sub-message carries public information, the second sub-message does not need to carry public information. For example, the second sub-message only needs to carry the terminal device's specific information, as well as the group ID and cell ID. The target cell can use the group ID and source cell ID in the second sub-message to index the public information in the first sub-message for the same group of terminal devices in the same set. For example, the second sub-message may also carry message attributes related to the first public information.

[0131] In some embodiments, the first message group may have different specific formats in different situations. These different formats may differ in the order of fields in the same sub-message, the order of different sub-messages in the same message group, and the information contained in the sub-messages.

[0132] As an example, the order of fields within the same sub-message can vary. To enhance the generality of the solution, there is no restriction on the order of the group ID, first public information, second public information, and proprietary information. For example, there is no restriction on the order of the group ID, basic public information, and optional public information within the first sub-message. The first sub-message carrying the public information portion may have the five formats shown in Figure 8.

[0133] 8 , in format 810 , the group ID generated by regrouping is placed at the header of the sub-message, followed by basic common handover request information and optional common handover request information between terminal devices in the same group.

[0134] 8 , the first sub-message carrying public information may also be designed according to format 820. Compared with format 810, the positions of the cell-level public information and the user-level public information in the public information portion of format 820 are swapped.

[0135] 8 , the first sub-message may also be designed according to formats 830 to 850. In formats 830 to 850, the first sub-message includes the group ID, cell-level public information, and user-level public information in different compositions.

[0136] While the order of fields within the first sub-message may vary, the order of fields within the remaining sub-messages within the message group is not restricted. For example, for the second sub-message, the group ID can be located at the beginning of the sub-message, or in the middle of the sub-message as shown in Figure 9. Referring to Figure 9, the second sub-message carries basic public information at the beginning, followed by the group ID, and then the specific information for the multiple terminal devices.

[0137] In some embodiments, the exclusive information and public information of a terminal device can be sent in different sub-messages. For example, when the message size limit is relatively strict or there is a lot of public information, the shared information and the exclusive information of the terminal device can be sent separately. The first sub-message sent first carries the complete basic public information and optional public information, and the second sub-message carries user-level information (exclusive information) specific to one or more terminal devices. For example, the second sub-message can carry exclusive information of no more than M terminal devices. An exemplary explanation is given below in conjunction with Figure 10.

[0138] The group handover request message group shown in Figure 10 includes a first sub-message 1010 and multiple second sub-messages 1020. As shown in Figure 10, due to the large amount of public information and strict message size restrictions, the first sub-message 1010 only carries the group ID, basic public information between each terminal device, and optional public information. The basic public information includes public handover request message attributes and public cell configuration information. The public cell configuration information includes the cell ID. The second sub-message 1020 carries the group ID, basic public information including only message attributes and the cell ID, and the specific information of M terminal devices (UE1 to UEM).

[0139] As shown in Figure 10, the cell-level information portion of the basic public information is already provided in the first sub-message, so the second sub-message does not need to carry it, and only needs to include information indicating the message attributes. In addition, the second sub-message carrying terminal device-specific information also needs to carry the corresponding group ID and source cell ID, so that the target network device can use the group ID and source cell ID to index the public information in the first sub-message for the same group of terminal devices in the same group.

[0140] In some embodiments, shared information and terminal device-specific information can be sent together. For example, in situations where message size restrictions are relatively relaxed or public information is relatively low, the terminal device-specific information and public information are sent in the same sub-message. For example, in addition to basic public information and optional public information, the first sub-message can also carry the specific information of no more than M terminal devices. The second sub-message carries the specific information of the remaining terminal devices. This is illustrated below with reference to Figure 11.

[0141] The group handover request message group shown in FIG11 includes a first sub-message 1110 and multiple second sub-messages 1120. Compared to FIG10 , due to less common information or a relatively loose message size limit, the first sub-message 1110 also carries the specific information of M terminal devices (UE1 to UEM). The second sub-message 1020 carries the specific information of the other M terminal devices (UEM+1 to UEM+M).

[0142] In some embodiments, shared information and the specific information for each terminal device are not combined and are sent separately. For example, in situations where message size restrictions are extremely strict or where it is desirable to minimize the impact on technical standards, messages are not combined. The first sub-message carries the complete common information portion, while the remaining sub-messages carry only the specific information for a single terminal device. In this case, the structure of the second sub-message can completely follow the message structure and fields of the terrestrial handover request, but the information already carried in the common message portion needs to be left blank. This is illustrated below with reference to Figure 12.

[0143] The group handover request message group shown in Figure 12 includes multiple second sub-messages, such as first sub-message 1210, second sub-message 1220, and second sub-message 1230. Compared to Figure 10 , first sub-message 1210 carries the same information as first sub-message 1010. However, each second sub-message carries information specific to only one terminal device. For example, second sub-message 1220 carries only information specific to terminal device UE1, while second sub-message 1230 carries only information specific to terminal device UE2.

[0144] Optionally, regardless of which of the above-mentioned transmission methods is used for the first message group, there is no restriction on the order of the fields in each sub-message. However, the group ID and public information must be placed before the dedicated information, so that when the target network device receives the dedicated information, it can combine the previously received public information to generate complete handover preparation information for the terminal device. In other words, there is no restriction on the order of the group ID, first public information, second public information, and dedicated information fields in the first and second sub-messages.

[0145] The above text introduces the message structure of the first message group in conjunction with Figures 7 to 12. The first message group includes common information that can be shared by terminal devices in the group based on two groupings. When sending, these common information are sent first, followed by user-level information that cannot be shared by each terminal device. Through this message structure, the information required for the switching request / response of multiple terminal devices is integrated in a reconstructed switching request / response message group. Since the common information field is shared by multiple terminal devices, information that originally needed to be sent multiple times only needs to be sent once, so the signaling overhead of the first message group is lower than the existing one signaling one user switching preparation process.

[0146] Continuing with Figure 6, in step S620, after the source network device sends the first message group, the target network device can obtain the handover preparation information of all terminal devices based on the received first message group. After receiving the handover preparation information, the target source network device can perform admission control on the terminal device on the network side to determine the handover request response.

[0147] In some embodiments, the target network device obtains the information of a single terminal device based on the public information in the first sub-message as follows: when the target network device receives the first sub-message in each message group, it needs to store the basic public information and optional public information carried in the first sub-message and its corresponding source cell ID and group ID. When the subsequent second sub-message arrives, the public parameter configuration of the terminal device in the message is indexed by the source cell ID (to distinguish the source cell to which the terminal device belongs, indexing the cell-level public information) and group ID (to distinguish the group to which the terminal device belongs in the regrouping, indexing the user-level public information) in the second sub-message, thereby obtaining complete switching preparation information for all terminal devices.

[0148] In some embodiments, due to the change in the format of the handover request message, the target network device does not need to perform handover access control on each terminal device one by one according to the information of each terminal device when performing access control. For example, since the first sub-message in the first message group carries the common information of the terminal devices in the same group, the target network device can first process the shared information between the terminal devices, and then process the exclusive information of each terminal device to perform hierarchical access control judgment. In other words, since the handover request and response messages are generated according to the structure of common information-user-level information, the target network device can also perform group access control judgment when performing the access control process according to user information. The target network device can first perform preliminary access control on all terminal devices in the same group based on the common information, and then perform user-level access control based on the non-shareable information of each terminal device, and finally complete the access control of all terminal devices, and generate a group handover request response to send back to the source network device.

[0149] As an embodiment, the target network device can perform access control according to the following process: first, the target network device can perform the first part of the access control judgment on all terminal devices in the same cell in the sub-message based on the basic public information in the group switching request; secondly, perform the second part of the access control judgment on all terminal devices in the same group based on the optional public information in the group switching request; thirdly, perform the third part of the access control judgment based on the user-level information of each terminal device carried in the group switching request; finally, merge the results of the three parts into a group switching request response message according to the same group classification.

[0150] In some embodiments, after receiving the first message group sent by the source network device, the target network device parses the handover preparation information of all terminal devices and performs admission control to obtain handover request response information from all terminal devices. To further reduce the latency of the handover request phase, the target network device is not required to perform regrouping. When merging information, the target network device uses the terminal device grouping used when the source network device sent it to the target network device.

[0151] For ease of understanding, the following exemplary description of the switching preparation phase of an embodiment of the present application is given with reference to FIG13 regarding the interaction between the source network device and the target network device regarding the group switching request and the group request response.

[0152] 13 , the source network device generates a group switching request by executing steps S1312 to S1316 , and the target network device generates a group switching request response by executing steps S1332 to S1338 .

[0153] In step S1312, the source network device predicts / decides the user's handover, and the prediction may include the user's handover target and its corresponding handover time.

[0154] In step S1314, the source network device groups users based on the handover prediction. Based on the handover prediction results, users that are (likely) switching to the same target network device at the same (nearly) time are grouped together, and users in the group that have some of the same handover preparation information are grouped together.

[0155] In step S1316, the source network device generates a group switching request message based on the information of each user, merges the information of the users in the group, and generates the group switching request message, which is the first message group mentioned above.

[0156] In step S1320 , the source network device sends the combined group switching request to the target network device.

[0157] In step S1332, after receiving the first message group sent by the source network device, the target network device parses the information of each user according to the group switching request.

[0158] In step S1334, the target network device performs hierarchical admission control on the user. Hierarchical admission control means that the public information in the handover request is prioritized for admission judgment, and then the admission judgment is performed based on the unique information of each user.

[0159] In step S1336, the target network device generates a handover request response for each user according to the admission control result of each user.

[0160] In step S1338, the target network device generates a handover request response message for the users in the same group. The target network device may generate a second message group as a group handover request response based on the same grouping standard.

[0161] In step S1340, the target network device sends a group switching request response back to the source network device. The source network device can parse the request switching responses of each user according to the second message group.

[0162] As shown in Figure 13, the present embodiment enhances the existing handover preparation phase for a single user to support group / batch user handover requests and responses. Users within the same group share some common information, which reduces the signaling overhead incurred during the handover preparation phase between the source and target network devices. Furthermore, the frequency of signaling interactions is reduced by merging request / response information from multiple users.

[0163] As described above, the group switch request response sent by the target network device to the source network device is also referred to as the second message group. To reduce latency, the target network device generates the second message group using the same grouping scheme as the first message group. In some cases, the target network device may also regroup all terminal devices in the first set of terminal devices.

[0164] The second message group can be used by the target network device to indicate the handover request responses of all terminal devices in the first terminal device group, and can also be called a group handover request response message group (GroupHandoverRequestAcknowledge message group, or simply GroupHOAck message group). In some embodiments, the target network device can determine a request response based on the handover request of each terminal device, and then combine them to generate a second message group corresponding to the first terminal device group.

[0165] In some embodiments, the second message group may include information required by all terminal devices in the first terminal device group to switch to the target network device, so that the source network device can prepare for the switch.

[0166] In some embodiments, the second message group is determined based on the target network device's admission control judgment. For example, the first public information is used by the target network device to make the first admission control judgment, the second public information is used by the target network device to make the second admission control judgment, and the specific information of each terminal device in the first message group is used by the target network device to make the third admission control judgment. The target network device can determine whether each terminal device in the first terminal device group initiates a cell handover based on the three admission control judgments, thereby generating the second message group.

[0167] As an embodiment, the result of the first admission control judgment can be used as the preliminary admission control judgment result for all terminal device groups in the first terminal device set, thereby improving the efficiency of admission control. Exemplarily, the result of the first admission control judgment can be temporarily retained, and when other terminal device groups in the first terminal device set make a handover request, the first admission control judgment does not need to be repeated.

[0168] As an embodiment, the result of the second admission control judgment may be applied to all terminal devices in the first terminal device group.

[0169] Similar to the first message group, the second message group contains multiple sub-messages. Exemplarily, the size of each sub-message does not exceed the preset message size, and each sub-message contains at least the group ID and its source base station ID. Exemplarily, only the first sub-message in each group needs to carry both basic public information and optional public information. When sending the second message group, the destination network device must prioritize each sub-message carrying the basic public information and optional public information, and then send the remaining sub-messages to the source network device.

[0170] The information content in the second message group is exemplarily described below with reference to Figure 14. Compared with Figure 7, the response information content of the second message group is similar to the request information content of the first message group. For the sake of simplicity, the information that has been explained will not be repeated.

[0171] The second message group can carry the information necessary for the target network to perform a handover between the source network device and the target network device, as configured by the target network for the terminal device. As shown in Figure 14, the second message group also includes a group ID, public information (public information includes basic public information and optional public information), and information specific to each terminal device.

[0172] After parsing and responding to the handover request message group for the same group of terminal devices, the target network device generates a second message group based on the original grouping of the terminal devices. Similarly, the public response information in this message group includes basic public information and optional public information. The basic public information includes cell-level public information of the target cell and response message attribute information, while the optional public information includes user-level information that is common among users.

[0173] The basic common information corresponds to the basic common HO Ack IEs field in FIG. 14 , the user-level common information corresponds to the optional common HO Ack IEs field in FIG. 14 , and the group ID is used to indicate the grouping information of the terminal device.

[0174] In addition to the common information, the second message group must also carry user-level information that cannot be shared between terminal devices, namely the handover acknowledgment information (special HO Ack IEs) fields specific to multiple terminal devices in Figure 14. This specific information includes, for example, security information pre-allocated by the target network device for the terminal device and the success of the user session transfer. To minimize the impact on existing standards, the existing data structure can be used for this information, but all IEs already included in the common information in each user-level information segment must be cleared. It is important to note that user-level information must at least include the ID of each terminal device.

[0175] Similar to the first message group, the second message group may also have different specific formats. Different formats may differ in the order of fields within the same sub-message, the order of different sub-messages in the same message group, and the information contained.

[0176] For example, the second message group also does not restrict the order of the group ID, basic public information, optional public information, and exclusive information. The following, with reference to Figure 15 , uses the first sub-message carrying public information as an example to illustrate five possible sub-message formats. It should be noted that the order of the fields in other sub-messages within the second message group is also unrestricted.

[0177] Referring to Figure 15, in format 1510, the group ID generated by regrouping is placed at the header of the sub-message, followed by public cell level information (basic public switching response information) and public user level information (optional public switching response information) between terminal devices in the same set.

[0178] 15 , the first sub-message carrying public information may also be designed according to format 1520. Compared with format 1510, the positions of the cell-level public information and the user-level public information in the public information portion in format 1520 are swapped.

[0179] As shown in Figure 15, the first sub-message may also be designed according to formats 1530 to 1550. In formats 1530 to 1550, the order of group ID, cell-level public information, and user-level public information included in the first sub-message is different.

[0180] On the other hand, similar to the first message group, there is no restriction on the specific content contained in each sub-message of the second message group. It is only required that the second message group carries the complete message content (including group ID, basic public information field, optional public information field, and user-specific user level information).

[0181] It should be noted that the order in which the sub-messages in the first message group (switching request message group) and the second message group (switching request response message group) arrive at the source / destination network device may be different. Regardless of the order in which the sub-messages arrive, it is sufficient that the public information portion arrives before the user-level information portion. However, in some cases (such as retransmission after a failed transmission), the public message portion may not arrive at the target / source network device before the user-level information. In this case, the source / destination network device needs to store the sub-message that arrives first without performing any processing and start a timer. If a sub-message carrying public information arrives before the timer expires, it will be processed according to the sub-message carrying the public information portion that arrived later; if the sub-message carrying public information does not arrive before the timer expires, the user-level information should be discarded and a message should be sent back to indicate the exception.

[0182] Based on the above introduction to the first and second message groups, it can be seen that the embodiments of the present application optimize the handover preparation phase of the relevant handover process and propose a handover preparation scheme suitable for grouped satellite NTN networks and its corresponding message format. In the embodiments of the present application, by adjusting the grouping process and message format, the handover signaling of each terminal device is reconstructed and merged into the same message group, which reduces the frequency of signaling interactions and also reduces signaling overhead. Furthermore, when performing access control based on user information, the target network device can also start with public information, perform partial access control on all terminal devices in the group, and then complete the full access control by combining the user-level information of all terminal devices, which also improves the efficiency of access control to a certain extent.

[0183] The handover preparation phase based on packet and signaling reconstruction is described in detail above through steps S610 and S620 of Figure 6 . For ease of understanding, a possible implementation of this method is described below in conjunction with the flowchart shown in Figure 16 . Figure 16 is written from the perspective of the interaction between the first terminal device, the second terminal device, the source network device, and the target network device. The first terminal device and the second terminal device may both belong to the first terminal device group.

[0184] 16 , in step S1610 , the first terminal device and the source network device perform measurement control and reporting.

[0185] In step S1620, the second terminal device and the source network device perform measurement control and reporting. There is no time sequence restriction between step S1620 and step S1610.

[0186] In step S1630, the source network device makes a handover decision / prediction, and the prediction result is used to group the terminal devices and generate a group handover request for each group based on the grouping.

[0187] In step S1640 , the source network device sends a group switching request, ie, a first message group, to the target network device.

[0188] In step S1650, the target network device performs admission control, and the admission control result is used to determine the handover response.

[0189] In step S1660 , the target network device sends a group switching response, ie, a second message group, to the source network device.

[0190] The primary purpose of grouping terminal devices is to facilitate grouped cell handovers, reducing the significant signaling overhead associated with individual handover preparations for each terminal device. Based on this grouping, when the source network device initiates a handover to a terminal device, grouped handover instructions can be issued, reducing the signaling overhead associated with individual handover instructions for all terminal devices. Therefore, it may be necessary to inform the terminal device of this grouping information during the handover preparation phase.

[0191] 6, in step S630, the source network device sends grouping information to the terminal device. The grouping information is used by the terminal device to determine the first terminal device group it is in. As mentioned above, the first terminal device group is any terminal device group in the first terminal device set performing cell handover.

[0192] The grouping information may include grouping result information or may include various information used for grouping. For example, the grouping information may include first grouping information directly indicating the first terminal device group to which the terminal device belongs. The terminal device may directly determine its group based on the first grouping information. In another example, the grouping information may include second grouping information used by the terminal device to calculate or determine its terminal device group. For example, the second grouping information may include multiple reference points and distance thresholds, allowing the terminal device to determine its group based on its location.

[0193] The grouping information can be sent to each terminal device in the first set of terminal devices in a variety of ways. For example, the first grouping information can be carried in existing signaling during the handover preparation phase, eliminating the need for additional signaling. In another example, the first grouping information can be sent via separate signaling to accommodate network devices with different handover prediction capabilities. In another example, the second grouping information can be sent via broadcast to multiple terminal devices within a cell to facilitate grouping by the terminal devices.

[0194] For ease of understanding, the following exemplary description of the method for sending group information is given in conjunction with FIG. 17 to FIG. 20 .

[0195] In some embodiments, when the source network device predicts and determines the first grouping information before receiving a measurement report from a terminal device, the source network device may send the first grouping information via signaling associated with the measurement report. For example, if the source network device is capable of making advance handover predictions for terminal devices, or can group the handover prediction results for each terminal device, the source network device may send the grouping results along with the measurement control signaling when performing measurement control on the terminal device.

[0196] Figure 17 is a flow chart showing the process of sending packet information in the measurement control phase. Referring to Figure 17, in step S1710, the source network device performs a handover decision / prediction. This prediction is performed before performing measurement control and reporting with the terminal device.

[0197] In step S1720 and step S1730, the source network device performs measurement control and reporting with the first terminal device and the second terminal device respectively. As shown in the figure, the packet information is sent to the two terminal devices along with the measurement control signaling.

[0198] The grouping information delivery scheme shown in Figure 17 will slightly increase the signaling size, but no additional signaling is required. Since the grouping is completed earlier, in the ground mobile cell scenario, it is possible to specify that a terminal device in the same set submits a measurement report to represent the measurement values ​​of all users in the group. For example, the source network device can instruct any terminal device in the first terminal device group to send a first measurement report based on the first grouping information. The first measurement report is used to indicate the measurement values ​​of all terminal devices in the first terminal device group.

[0199] In some embodiments, if the network device cannot complete the handover prediction at an earlier time as shown in Figure 17, it may consider adding a handover packet signaling to deliver the packet information to the user. This signaling delivery occurs between steps S220 and S270 shown in Figure 2. For example, the source network device may send the first packet information via separate signaling before sending the first message group to the target network device.

[0200] FIG18 is a flow chart showing the process of sending group information through newly added separate signaling. Referring to FIG18 , steps S1810 to S1830 are consistent with steps S1610 to S1630 in FIG16 , and steps S1860 to S1880 are consistent with steps S1640 to S1660 in FIG16 , and are not described in detail here.

[0201] In step S1840 and step S1850, the source network device sends group information to the first terminal device and the second terminal device respectively. The first terminal device and the second terminal device may belong to the same terminal device group.

[0202] In step S1860, the source network device sends handover initiation signaling to the two terminal devices respectively.

[0203] The packet information delivery solution shown in Figure 18 requires additional signaling and has relatively poor performance, but it is applicable to networks with different user handover prediction capabilities. In other words, regardless of the time point in the handover preparation phase when the network completes the handover prediction for the terminal device, the packet information can be delivered in this way.

[0204] In some embodiments, since the user-level information of a terminal device must be sent via unicast, to avoid adding additional message types, the packet information can be sent along with the handover initiation message sent by the source network device to the terminal device. User-level information is, for example, non-sharable information carried in the RRC. For example, the source network device can send the first packet information based on the received handover request response. For example, the first packet information can be sent via the handover initiation message corresponding to the terminal device.

[0205] FIG19 is a flow chart showing the process of sending group information in the handover initiation phase. Referring to FIG19 , since steps S1910 to S1960 are the same as steps S1610 to S1660 in FIG16 , they will not be described in detail here.

[0206] In step S1970, the source network device sends a handover initiation signaling to the two terminal devices respectively, where the handover initiation signaling includes the sent grouping information.

[0207] In the packet information delivery solution shown in Figure 19, the packet information is sent to the terminal device along with the terminal device's dedicated information, slightly increasing the signaling size without requiring additional signaling. However, the packet information is delivered relatively late, and the process optimizations supported by packet signaling are relatively limited.

[0208] In some embodiments, when the source network device performs the first grouping, it groups terminal devices that are directed to the same target cell at the same / similar time into the same set. The source network device can broadcast grouping criteria to the terminal devices in the set, allowing the terminal devices to group themselves. For example, in a terrestrial mobile cell scenario, terminal devices with similar geographical locations will usually be directed to the same target cell at the same / similar time, so the network device can broadcast multiple reference points and distance thresholds. After the terminal devices complete the grouping based on their own locations, they will report the grouping information to the network side along with the measurement report.

[0209] Exemplarily, the source network device may send the second grouping information by broadcasting. The second grouping information is used by the terminal devices in the first terminal device set to determine the first terminal device group they are in. The terminal devices may report the determined grouping information to the source network device.

[0210] Figure 20 is a flow chart showing the process of the terminal device grouping and reporting based on the grouping standard broadcast by the network side. Referring to Figure 20, the handover decision / prediction in step S2010 is consistent with step S1710 in Figure 17 and will not be repeated here.

[0211] In step S2020, the source network device sends the grouping criteria via broadcast.

[0212] In step S2030 and step S2040, the source network device performs measurement control and reporting with the first terminal device and the second terminal device respectively. As shown in the figure, the packet information is reported to the source network device along with the measurement report.

[0213] In the packet information delivery scheme shown in Figure 20, the network broadcasts multiple reference points and distance thresholds. The terminal device calculates the closest reference point based on its own location to complete the grouping. This scheme increases broadcast signaling overhead. When the terminal device reports the packet information to the network along with the measurement report, the size of the uplink measurement report signaling is slightly increased. The timing of grouping completion is similar to the scheme shown in Figure 17, but there is no need to report the terminal device's own location information.

[0214] The above text, in conjunction with Figures 6 to 20, takes the handover preparation stage as an example to detail the technical solution for handover signaling interaction and grouping information distribution based on two groupings of terminal devices in an embodiment of the present application. This technical solution flexibly merges the handover request and response information of a single terminal device, so that one message carries the information required for the handover of multiple terminal devices, and eliminates the repeated transmission of the same information, ultimately reducing the frequency of signaling interaction while reducing signaling overhead. The target network device performs a grouped admission control judgment process, which also improves the efficiency of admission control to a certain extent.

[0215] For ease of understanding, the following uses an example of a satellite performing cell handover preparation for multiple users (eg, UEs) in a cell to introduce a scenario in which the present application is applied to cell handover in an NTN system in combination with multiple embodiments.

[0216] Example 1

[0217] In the terrestrial fixed cell scenario shown in Figure 2, users in the fixed cell can use UE i = , i is a natural number greater than or equal to 1. Before the satellite 210 ends the service, the source network device can determine the UE i The next target satellite to be switched is SAT j ,j=1,2,……,P i , P i UE representing network equipment prediction / decision i The number of target satellites that can be switched to next time. The network equipment may not finally determine the user's target satellite, but may determine multiple possible target satellites.

[0218] Since the coverage of satellite cells is much larger than that of ground cells, the number of users in a cell may be much larger than the number of users in a single ground cell. Assume that the number of users in the current cell is N and the serving satellite is SAT A When , the handover prediction / decision results of all users may be as shown in Table 1.

[0219] Table 1

[0220] Table 1 shows the handover prediction / decision results for N users served by satellite A. In the Earth-fixed cell scenario, all users in the same cell typically switch to the same satellite. Therefore, different users in the handover prediction / decision usually have the same (candidate) target satellite, and all users will switch to the target satellite within the same time window.

[0221] Based on factors such as network device performance, message rate, and expected processing latency, the amount of user information carried in a single group handover request message must not exceed M. The steps for generating a handover request message group for M users are primarily divided into three steps: initial user grouping, user regrouping, and request message generation based on the grouping results. The specific process is described below.

[0222] 1. Initial user grouping

[0223] The purpose of initial user grouping is to identify all users that are tangentially directed to the same target satellite at the same or adjacent times, allowing for grouped handover requests. In geostationary cells, user handovers due to satellite mobility have a unified target satellite and consistent handover window timing, so most users are grouped together in the initial grouping. However, some users at the edge of the cell may have different target satellites. Users can be grouped based on their distance from the cell center. All users not at the cell edge are grouped together, while users at the cell edge, which may tangentially direct to other cells due to mobility, are grouped based on their potential target cells.

[0224] In order to distinguish it from the following regrouping step, the result of the initial grouping is defined as the user set {UE i} x , where x is the target satellite for handover. i} x Refers to all users that are tangential to the target satellite x. In the initial user grouping, since there may be more than one target satellite, a user may belong to multiple user groups at the same time. For example, UE1 exists in both the source satellite SAT A Send to target satellite SAT B In the message group, it also exists in the message sent to the target satellite SAT C message group.

[0225] 2. User regrouping

[0226] The purpose of user regrouping is to group users with the same or identifiable parameter configurations into the same group, so that all users in the group can share these same parameter configurations. For example, users in close proximity can share the same set of geolocation parameters; users with similar QoS may have the same RMM measurement configurations.

[0227] Different from the initial grouping, a group ID needs to be added in the re-grouping. Each group of users corresponds to a unique group identifier GID (Group ID), which is used to indicate the grouping attribute of the message in the re-grouping.

[0228] 3. Generate request message based on grouping results

[0229] In the initial grouping, the set {UE i} x Since these users have the same source / target cell, they can share the same set of source / target cell-related cell-level information and some other public information used to indicate the attributes of the message itself, which is called basic public information. The possible basic public information list is shown in Table 2.

[0230] Table 2

[0231] In the further grouping, users with the same GID share some user-level information, which is called optional public information. According to different grouping criteria, the possible optional public information list is shown in Table 3.

[0232] Table 3

[0233] In extreme cases, if no user-level information can be found that can be shared between users, the optional common information is left blank.

[0234] After obtaining the common information among users in the same group according to the above grouping results, combined with the user-level information of all users, the first sub-message in the possible group switching request message group is generated as shown in the first sub-message 1110 in Figure 11.

[0235] The first sub-message in a handover request message group contains the group identifier, common information, and user-specific information in sequential order. The common information section contains basic common information and optional common information. The basic common information section corresponds to cell-level configuration information and some attributes of the message itself. User-specific information, which is unique to each user and cannot be shared, is sequentially displayed, with each field corresponding to a specific user. Table 4 shows possible user-specific information.

[0236] Table 4

[0237] It should be noted that the specific format of the above message is only one possible example in this example, and the specific field order is not limited, but the public information field and group ID should precede the user-specific information.

[0238] In order to distinguish the group identifiers of the handover request and response messages, the group identifier in the handover request message is hereinafter referred to as GID_REQ, and the group identifier in the handover request response message is referred to as GID_ACK.

[0239] Due to the limitation of message size, a single handover request message group sub-message can only carry a limited number of users. i} xIf the number of users with the same GID_REQ in a message exceeds the message size limit, the user information corresponding to the GID_REQ must be sent in multiple messages. In this case, only the public information portion needs to be filled in the first message. For subsequent messages, the group to which the message belongs can be determined by the cell ID and group identifier GID_REQ. The public information portion of the first message with the same group will be used as the public information portion of subsequent messages. In the public information portion of the subsequent message, the public cell configuration (except the cell ID) and optional public information are left blank. The format of subsequent messages within the same group is shown in the second sub-message 1120 of Figure 11.

[0240] In this embodiment, after the target cell receives the group handover request from the source cell, it performs access control based on the public information and user-specific information contained in the message. In the traditional access control stage, the target cell needs to make layer-by-layer judgments based on the user information carried in the request, and generate different access judgment results based on the user's field information. In the group handover request and response of the embodiment of the present application, the target network device can first generate a public access judgment result applicable to all users in the same group based on the public information between users, and then perform user-level access control judgment. Finally, the public access control result and the user-level result are merged to obtain the access control result for all users, thereby improving the efficiency of access control.

[0241] When performing admission control, the target cell needs to first perform group admission control based on the public information in the message, and then perform specific admission control based on the user-level information of each user. The possible process is as follows.

[0242] 1. Perform the first part of the admission control judgment on all users in the same cell in the sub-message according to the basic public information in the group handover request.

[0243] 2. Perform the second part of the admission control judgment on all users in the same group based on the optional public information in the group switching request.

[0244] 3. Execute the third part of the admission control judgment based on the user level information of each user carried in the group switching request.

[0245] 4. Combine the results of the three parts into a group handover request response message according to the same group classification.

[0246] After the target network device obtains the admission control result of each user, it will no longer perform additional regrouping when responding to the handover request, unlike the handover request message generation process of the source cell, so it will not increase the delay in the handover request and response process. This is because the result is for the same set {UE i} xAll users in the same group must have the same source cell, and the handover request responses of users in the same group are likely to share some information. The specific content of the handover request response is as follows.

[0247] In the initial grouping completed by the source cell, the set {UE i} x With the same source / target cell, these users can share the same set of source / target cell-related cell-level information and some other common information used to indicate the attributes of the message itself, which is called basic common information. The possible basic common information is listed in Table 5.

[0248] Table 5

[0249] In the re-grouping, the grouping result of the source cell is used, and users with the same GID_ACK share some user-level information, which is called optional common information. The possible optional common information is listed in Table 6.

[0250] Table 6

[0251] In extreme cases, if no user-level information that can be shared between users can be found, the optional public information is left blank.

[0252] After obtaining the common information among users in the same group according to the above grouping results, combined with the user level information of all users, the first sub-message structure of the switching request response message group is generated to be the same as the first sub-message 1110 in Figure 11, and the request message is replaced by the response message.

[0253] In the handover request response message group, the GID_ACK, common information section, and user-specific information section are sequentially connected. The common information section includes basic common information and optional common information. The basic common information section corresponds to cell-level configuration information and some attributes of the message itself. The user-specific information corresponds to information that is unique to each user and cannot be shared. These sections are sequentially connected, with each section corresponding to user-level information for a single user.

[0254] Similar to the request message group, due to message size limitations, a single sub-message in the response message group can only carry a limited number of users. If the number of users with the same GID_ACK within the same user set {UEi}x exceeds the message size limit, the user information corresponding to that GID_ACK must be sent in multiple messages. In this case, only the common information portion needs to be filled in the first message. For subsequent sub-messages, the group to which the message belongs can be determined based on the cell ID and group identifier GID_ACK. The common information portion of the first message with the same group can be directly used as the common information portion of subsequent messages.

[0255] After receiving the handover request response message from each user, the source cell side parses the information of each user required to make a handover decision. Thus, the handover preparation phase is completed.

[0256] Example 2

[0257] In the terrestrial mobile cell scenario shown in Figure 3, users can also use UE i , where i is a natural number greater than or equal to 1. Since the coverage area of ​​a satellite cell moves with the satellite, users in different locations will leave the coverage of the source cell at different times and will also switch to different (candidate) target satellites at different times. When grouping users, each user's switching time must also be considered. For simplicity, this example assumes that the satellite determines that each user has only one target satellite.

[0258] The source network device can make handover predictions / decisions based on the motion trajectory of the serving satellite and other nearby satellites, the user's location, and other information. i The target satellite SAT switched at time τ i τ refers to the handover window. Unlike terrestrial fixed-cell scenarios, satellite mobility causes different handover timings for each user, so the specific handover time for each user must be taken into account. Assuming the number of users in the current cell is N, the possible handover prediction / decision results for each user are shown in Table 7.

[0259] Table 7

[0260] Table 7 shows the handover prediction / decision results for N users served by satellite 310. For the Earth mobile cell scenario, all users in the same cell usually switch to different satellites at different times.

[0261] Similarly, based on factors such as network-side device performance, message rate, and expected processing latency, the amount of user information carried in a single group handover request message must not exceed M. The steps for designing a group handover request message for M users are still divided into three steps: initial user grouping, user regrouping, and request message generation based on the grouping results. The specific process is described below.

[0262] 1. Initial user grouping

[0263] The purpose of initial user grouping is to identify all users that are tangentially directed to the same target satellite at the same or adjacent times, allowing for grouped handover requests. In a geostationary cell scenario, user handovers caused by satellite mobility do not have a unified target satellite or consistent handover window. However, users in close proximity often have the same or similar handover timings and target cells. Therefore, using the handover prediction results of each user, geographically close users with the same or similar handover timings and targets are grouped into the same group.

[0264] In order to distinguish it from the following regrouping step, the result of the initial grouping is defined as the user set UE x,τ In this definition, x is the target satellite for handover, and τ is the set of UE x,τ When the user switches within the group, the UE x,τ Refers to all users that are tangential to the target satellite x at time τ.

[0265] 2. User regrouping

[0266] Similarly, the purpose of user regrouping is to group users with the same or identifiable parameter configurations into the same group, so that all users within the group can share these same parameter configurations. For example, users in close proximity can share the same set of geolocation parameters and may also have the same RMM measurement configuration. The possible user-level sharing information in this example is shown in Table 8.

[0267] Table 8

[0268] In the re-grouping, each group of users corresponds to a unique group identifier GID_REQ, which is used to indicate the grouping attribute of the message in the re-grouping.

[0269] 3. Generate request message based on grouping results

[0270] Similarly, in the initial grouping, the UE x,τ With a unified source / target cell, these users can share the same set of source / target cell-related cell-level information and some other public information used to indicate the attributes of the message itself, which is called basic public information.

[0271] In the regrouping, users with the same GID_REQ share some user-level information, which is called optional common information. In the most extreme case, if no user-level information can be shared between users, the optional common information is left blank.

[0272] After obtaining the common information among users in the same group based on the above grouping results, combined with the user-level information of all users, a group switching request message group is generated and sent to satellites 320 and 330 as shown in FIG11 .

[0273] Similarly, due to message size limitations, a single sub-message can only carry a limited number of users. However, in terrestrial mobile cell scenarios, initial grouping places geographically close users into the same group. Since the number of users in a group is small, it can be difficult to find more shared information when regrouping within the group. Therefore, a method is used to combine public information with user-specific information for transmission.

[0274] In the message group shown in Figure 11, the first message only needs to contain the public information section. For subsequent sub-messages, the group to which the message belongs is determined by the cell ID and group identifier GID_REQ. The public information section of the first message belonging to the same group is used as the public information section of subsequent messages. In the public information section of subsequent messages, the public cell configuration (except the cell ID) and optional public information are left blank.

[0275] Example 3

[0276] In the feeder link handoff shown in Figure 4, as the satellite leaves the service range of the source gateway and gradually enters the service range of the destination gateway, it may also trigger a switch in the user's serving base station. As shown in Figure 4, as satellite 410 leaves the service range of source gateway 430 and gradually enters the service range of destination gateway 440, the serving base station for all users within the satellite cell switches from base station 420 to target base station 450.

[0277] In this scenario, the user handover prediction results are similar to those in the terrestrial fixed cell scenario. Assuming that the message size limit in this example is relatively strict, to meet the size limit of a single message, information about users in the same group at source base station 420 is sent to target base station 450 by sending shared information and user-level information separately for handover admission control. In this case, all users tangentially connected to the same target base station are regrouped, and users with the same / similar user-level information are grouped together. The source base station then initiates a handover request for this group of users to the target base station at the appropriate time.

[0278] In this handover request, a group of messages is sent to deliver basic handover information for each user to target base station 450. Within this group of messages, public information and the group information (group ID and source cell ID) to which the public information belongs must be preferentially sent to target base station 450 as shown in the first sub-message 1110 of FIG10 .

[0279] Subsequently, a sub-message (eg, the second sub-message 1120 shown in FIG10 ) carrying the user-level information specific to each user is sent to the target base station 450. Due to size limitations, the number of users carried in a single message should not exceed M.

[0280] When the target base station receives the first sub-message, it stores the public information and its corresponding group. When subsequent sub-messages arrive, they are indexed by group ID and cell ID to obtain all the necessary information for the handover preparation phase and perform step-by-step admission control.

[0281] Example 4

[0282] In some cases, there is no common information between users. In this embodiment, it is also necessary to group the users for the first time to form a user set. However, because the user set contains too few users, it is not possible to find user-level information that can be shared by users in the same set during the second grouping.

[0283] In the initial grouping, the set {UE i} x With a unified source / target cell, users in a group can share the same set of source / target cell-related cell-level information and some other common information used to indicate the attributes of the message itself, which is called basic common information. Table 5 lists possible basic common information.

[0284] In this embodiment, no user-level information that can be shared between users can be found, and the optional common information is left blank. The first sub-message in the group switch request message group is shown as the first sub-message 1010 in FIG10 .

[0285] Subsequently, a sub-message carrying user-level information of each user is sent to the target base station. Assuming that the size of a single message does not exceed the RRC message size in the original handover request, each sub-message can carry the RRC message of one user, as shown in the second sub-message 1220 in FIG12 .

[0286] In this embodiment, compared with the traditional solution without grouping, only cell-level public information can be shared, and the signaling overhead saved is relatively small.

[0287] Example 5

[0288] In some cases, there is a lot of common information between users. In this embodiment, it is also necessary to initially group users to form user sets. However, since the user sets contain multiple users with similar properties (for example, belonging to the same IoT device), there is a lot of information that can be shared between users.

[0289] In the initial grouping, the set {UE i} x With a unified source / target cell, users in a group can share the same set of source / target cell-related cell-level information and some other common information used to indicate the attributes of the message itself, which is called basic common information. Table 5 lists possible basic common information.

[0290] In the sub-grouping, users with the same GID_REQ share some user-level information, which is called optional common information. The possible optional common information is listed in Table 9.

[0291] Table 9

[0292] In this embodiment, there is a lot of shared information between users. Therefore, there is a lot of blank space in the user-level information of each user. This actually reduces the size of the portion carrying user RRC information. Therefore, it is suitable to adopt a mode in which the first sub-message carries the common information portion, and the remaining sub-messages carry the user-level information of multiple users. The format of the first sub-message can be referred to as the first sub-message 1010 shown in Figure 10.

[0293] In the handover request message group, user-specific information corresponds to information that is unique to each user and cannot be shared. This information is sequentially connected, with each field corresponding to a user. Possible user-specific information is shown in Table 4.

[0294] A sub-message carrying user-level information for each user is sent to the target base station. This assumes that the size of a single message does not exceed the RRC message size in the original handover request. However, due to the smaller size of user information, each sub-message can carry RRC information for M users. The formats of the remaining sub-messages can refer to the second sub-message 1020 shown in Figure 10 .

[0295] After receiving the handover request response message from each user, the source cell side parses the information of each user required to make a handover decision. Thus, the handover preparation phase is completed.

[0296] The above, combined with various examples, describes how the present invention optimizes the signaling interactions during the handover preparation phase as specified in relevant standards. Based on the principle of sharing common information between users, the present invention optimizes the interaction between single-user handover requests and responses into a scheme suitable for group-user handover requests and responses in the NTN satellite network. This method restructures the original message to generate a message group for signaling interactions between source and target network devices during the handover preparation phase. The size of each sub-message within this message group can be flexibly adjusted to suit different scenarios.

[0297] The embodiments of the present application help reduce the signaling overhead when multiple terminal devices perform cell handovers simultaneously. Figure 21 is a comparative diagram of the related art and the present application. As shown in Figure 21, in the related art on the left, each terminal device (UE1, UE2, ...) corresponds to a handover request / response, while the figure on the right shows the group handover request / response after applying the embodiment of the present application. With the related art, the amount of signaling required by the NTN for cell handovers will increase dramatically. The embodiment of the present application generates a handover request / response message group based on the shared information of the two groupings. The message group flexibly merges the information of multiple terminal devices to reduce signaling overhead. For example, since the shared information is extracted and transmitted separately, the signaling overhead can be reduced, and the user level information of each terminal device can be partially omitted compared to the original, which reduces the space occupied. Furthermore, the reduced information of different users can be combined and transmitted in a sub-message in the message group, but the specific number of users that a single sub-message can carry needs to be determined based on the size limit and the size of the shared information. Overall, the message group of the embodiment of the present application can outperform the original solution of a single message carrying single user information in terms of total message size and number.

[0298] The method embodiment of the present application is described in detail above in conjunction with Figures 1 to 21. The device embodiment of the present application is described in detail below in conjunction with Figures 22 to 25. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for portions not described in detail, reference can be made to the above method embodiment.

[0299] FIG22 is a schematic block diagram of a network device according to an embodiment of the present application. The device 2200 may be any source network device described above. The device 2200 shown in FIG22 includes a determining unit 2210 and a sending unit 2220.

[0300] The determining unit 2210 may be configured to determine a first terminal device group within a first terminal device set that performs cell switching, where the first terminal device set includes one or more first terminal device groups.

[0301] The sending unit 2220 can be used to send a first message group to the target network device, where the first message group is used to indicate a switching request for all terminal devices in the first terminal device group; wherein the first message group includes first public information related to the source cell corresponding to the source network device and / or the target cell corresponding to the target network device, and second public information related to the terminal devices in the first terminal device group.

[0302] Optionally, the first message group includes at least one sub-message, and each sub-message in the at least one sub-message includes first identification information corresponding to the first terminal device group and second identification information corresponding to the source cell.

[0303] Optionally, the first message group includes a first sub-message and a second sub-message, the first sub-message is a sub-message sent preferentially in the first message group, and the first sub-message includes first public information and second public information.

[0304] Optionally, the first public information includes the cell configuration information of the source cell and the message attributes related to the first public information, the cell configuration information includes the second identification information corresponding to the source cell, and the second sub-message includes the message attributes related to the first public information and the second identification information in the first public information.

[0305] Optionally, the first message group further includes exclusive information of all terminal devices in the first terminal device group, and the exclusive information is used by the target network device to determine the switching request of each terminal device in the first terminal device group.

[0306] Optionally, the first message group includes at least one sub-message. If one sub-message in at least one sub-message includes terminal device-specific information, one sub-message in at least one sub-message includes exclusive information of M terminal devices in the first terminal device group, where M is a natural number greater than or equal to 1.

[0307] Optionally, the apparatus 2200 further includes a first receiving unit, configured to receive a second message group sent by the target network device, where the second message group is used by the target network device to indicate a handover request response from all terminal devices in the first terminal device group.

[0308] Optionally, the second message group is determined based on the access control judgment of the target network device, the first public information is used for the target network device to perform a first access control judgment, the second public information is used for the target network device to perform a second access control judgment, and the exclusive information of each terminal device in the first message group is used for the target network device to perform a third access control judgment.

[0309] Optionally, the sending unit is further configured to send first grouping information to each terminal device in the first terminal device set, where the first grouping information is used to indicate the first terminal device group to which the terminal device belongs.

[0310] Optionally, the determining unit is further configured to determine first grouping information before receiving a measurement report from the terminal device, and the first grouping information is sent via signaling related to the measurement report.

[0311] Optionally, the apparatus 2200 further includes an indication unit, configured to indicate, according to the first grouping information, any one terminal device in the first terminal device group to send a first measurement report, where the first measurement report is used to indicate measurement values ​​of all terminal devices in the first terminal device group.

[0312] Optionally, the sending unit is further configured to send the first group information through separate signaling before sending the first message group to the target network device.

[0313] Optionally, the sending unit is further used to send first grouping information according to the received switching request response, the switching request response is used to indicate whether each terminal device in the first terminal device group initiates switching, and the first grouping information is sent through the switching initiation message corresponding to the terminal device.

[0314] Optionally, the sending unit is further used to send second grouping information by broadcasting, and the second grouping information is used by the terminal devices in the first terminal device set to determine the first terminal device group to which they belong; the device 2200 also includes a second receiving unit, which can be used to receive the grouping status reported by the terminal device.

[0315] Optionally, the source cell includes one or more first terminal device sets, and the one or more terminal device sets are determined based on one or more of the following information: the target cell corresponding to the terminal device in the source cell; and the time when the terminal device in the source cell performs cell switching.

[0316] Optionally, one or more first terminal device groups are determined based on one or more of the following information: the geographical location of the terminal devices in the first terminal device set; the radio frequency range supported by the terminal devices in the first terminal device set; the type of the terminal devices in the first terminal device set; and the ability of the terminal devices in the first terminal device set to access different access networks.

[0317] FIG23 is a schematic block diagram of another network device provided in an embodiment of the present application. The device 2300 can be any target network device described above. The device 2300 shown in FIG23 includes a receiving unit 2310.

[0318] The receiving unit 2310 can be used to receive a first message group sent by a source network device, where the first message group is used to indicate a switching request for all terminal devices in a first terminal device group. The first terminal device group is any terminal device group in a first terminal device set that performs cell switching, and the first terminal device set includes one or more first terminal device groups; wherein the first message group includes first public information related to a source cell corresponding to the source network device and / or a target cell corresponding to the target network device, and second public information related to the terminal devices in the first terminal device group.

[0319] Optionally, the first message group includes at least one sub-message, and each sub-message in the at least one sub-message includes first identification information corresponding to the first terminal device group and second identification information corresponding to the source cell.

[0320] Optionally, the first message group includes a first sub-message and a second sub-message, the first sub-message is a sub-message sent preferentially in the first message group, and the first sub-message includes first public information and second public information.

[0321] Optionally, the first public information includes the cell configuration information of the source cell and the message attributes related to the first public information, the cell configuration information includes the second identification information corresponding to the source cell, and the second sub-message includes the message attributes related to the first public information and the second identification information in the first public information.

[0322] Optionally, the first message group further includes exclusive information of all terminal devices in the first terminal device group, and the exclusive information is used by the target network device to determine the switching request of each terminal device in the first terminal device group.

[0323] Optionally, the first message group includes at least one sub-message. If one sub-message in at least one sub-message includes terminal device-specific information, one sub-message in at least one sub-message includes exclusive information of M terminal devices in the first terminal device group, where M is a natural number greater than or equal to 1.

[0324] Optionally, the apparatus 2300 further includes a sending unit, which is configured to send a second message group to the source network device, where the second message group is used by the target network device to indicate a switching request response from all terminal devices in the first terminal device group.

[0325] Optionally, the second message group is determined based on the access control judgment of the target network device, the first public information is used for the target network device to perform a first access control judgment, the second public information is used for the target network device to perform a second access control judgment, and the exclusive information of each terminal device in the first message group is used for the target network device to perform a third access control judgment.

[0326] Optionally, the source cell includes one or more first terminal device sets, and the one or more terminal device sets are determined based on one or more of the following information: the target cell corresponding to the terminal device in the source cell; and the time when the terminal device in the source cell performs cell switching.

[0327] Optionally, one or more first terminal device groups are determined based on one or more of the following information: the geographical location of the terminal devices in the first terminal device set; the radio frequency range supported by the terminal devices in the first terminal device set; the type of the terminal devices in the first terminal device set; and the ability of the terminal devices in the first terminal device set to access different access networks.

[0328] FIG24 is a schematic block diagram of a terminal device provided in an embodiment of the present application. The device 2400 may be any of the terminal devices described above. The device 2400 shown in FIG24 includes a determining unit 2410.

[0329] Determination unit 2410 can be used to determine the first terminal device group in which the terminal device is located. The terminal device performs cell switching from a source cell corresponding to a source network device to a target cell corresponding to a target network device. The first terminal device group is any terminal device group in the first terminal device set that performs cell switching. The first terminal device set includes one or more first terminal device groups.

[0330] Optionally, the apparatus 2400 further includes a first receiving unit, which is configured to receive first grouping information sent by a source network device, where the first grouping information is used to indicate a first terminal device group to which the terminal device belongs.

[0331] Optionally, the first grouping information is determined before the source network device receives the measurement report of the terminal device, and the first grouping information is sent through signaling related to the measurement report.

[0332] Optionally, the apparatus 2400 further includes a first sending unit, configured to send a first measurement report according to an instruction of the source network device, where the first measurement report is used to indicate measurement values ​​of all terminal devices in the first terminal device group.

[0333] Optionally, the first receiving unit is further configured to receive first packet information sent by the source network device through separate signaling, where the separate signaling is sent before the source network device sends a handover request to the target network device.

[0334] Optionally, the first receiving unit is also used to receive a switching initiation message sent by the source network device, the switching initiation message includes first grouping information, the switching initiation message is determined based on the switching request response received by the source network device, and the switching request response is used to indicate whether each terminal device in the first terminal device group initiates a switch.

[0335] Optionally, the device 2400 also includes a second receiving unit, which can be used to receive second grouping information through broadcasting, and the second grouping information is used by the terminal device to determine the first terminal device group to which it belongs; a second sending unit, which can be used to report the corresponding first terminal device group to the source network device.

[0336] Optionally, one or more first terminal device groups are determined based on one or more information: the geographical location of the terminal devices in the first terminal device set; the radio frequency range supported by the terminal devices in the first terminal device set; the type of the terminal devices in the first terminal device set; and the ability of the terminal devices in the first terminal device set to access different access networks.

[0337] Figure 25 shows a schematic block diagram of a communication device according to an embodiment of the present application. The dashed lines in Figure 25 indicate that the unit or module is optional. Device 2500 can be used to implement the method described in the above method embodiment. Device 2500 can be a chip, a terminal device, or a network device.

[0338] The device 2500 may include one or more processors 2510. The processor 2510 may support the device 2500 to implement the method described in the method embodiment above. The processor 2510 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0339] The apparatus 2500 may further include one or more memories 2520. The memories 2520 store programs that can be executed by the processor 2510, causing the processor 2510 to perform the methods described in the above method embodiments. The memories 2520 may be independent of the processor 2510 or integrated into the processor 2510.

[0340] The apparatus 2500 may further include a transceiver 2530. The processor 2510 may communicate with other devices or chips via the transceiver 2530. For example, the processor 2510 may transmit and receive data with other devices or chips via the transceiver 2530.

[0341] The present application also provides a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to a terminal device or network device provided in the present application, and the program enables a computer to execute the method performed by the terminal device or network device in each embodiment of the present application.

[0342] The computer-readable storage medium may be any available medium that can be read by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a digital versatile disc (DVD)), or a semiconductor medium (e.g., a solid state drive (SSD)).

[0343] The present application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to a terminal device or network device provided in the present application, and the program causes a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0344] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0345] The present application also provides a computer program that can be applied to a terminal device or network device provided in the present application, and enables a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0346] The terms "system" and "network" may be used interchangeably in this application. In addition, the terms used in this application are only used to explain the specific embodiments of this application and are not intended to limit this application. The terms "first," "second," "third," and "fourth," etc. in the specification and claims of this application and the accompanying drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions.

[0347] In the embodiments of this application, the term "indication" may refer to a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" may refer to a direct indication of B, e.g., B can obtain information through A; it may refer to an indirect indication of B, e.g., A indicates C, e.g., B can obtain information through C; or it may refer to an association between A and B.

[0348] In the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and indication, configuration and configuration, etc.

[0349] In the embodiments of the present application, "pre-definition" or "pre-configuration" may be implemented by pre-storing corresponding codes, tables, or other methods that can be used to indicate relevant information in a device (e.g., including a terminal device and a network device). The present application does not limit the specific implementation method. For example, pre-definition may refer to a definition in a protocol.

[0350] In the embodiments of the present application, the "protocol" may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, a NR protocol, and related protocols used in future communication systems, and this application does not limit this.

[0351] In the embodiments of the present application, determining B based on A does not mean determining B only based on A. B can also be determined based on A and / or other information.

[0352] In the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0353] In various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0354] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0355] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0356] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0357] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A cell switching method, characterized in that: Applied to handover from a source cell corresponding to a source network device to a target cell corresponding to a target network device, the method comprising: The source network device determines a first terminal device group in a first terminal device set that performs the cell handover, where the first terminal device set includes one or more of the first terminal device groups; The source network device sends a first message group to the target network device, where the first message group is used to indicate a switching request of all terminal devices in the first terminal device group; The first message group includes first public information related to the source cell and / or the target cell and second public information related to the terminal devices in the first terminal device group.

2. The method according to claim 1, characterized in that The first message group includes at least one sub-message, and each sub-message in the at least one sub-message includes first identification information corresponding to the first terminal device group and second identification information corresponding to the source cell.

3. The method according to claim 1, characterized in that The first message group includes a first sub-message and a second sub-message, the first sub-message is a sub-message that is sent preferentially in the first message group, and the first sub-message includes the first public information and the second public information.

4. The method according to claim 3, characterized in that The first public information includes the cell configuration information of the source cell and the message attributes related to the first public information, the cell configuration information includes the second identification information corresponding to the source cell, and the second sub-message includes the message attributes related to the first public information and the second identification information in the first public information.

5. According to the method described in any one of claims 1-4, the first message group also includes exclusive information of all terminal devices in the first terminal device group, and the exclusive information is used by the target network device to determine the switching request of each terminal device in the first terminal device group.

6. The method according to claim 5, characterized in that The first message group includes at least one sub-message. If one sub-message in the at least one sub-message includes the terminal device-specific information, one sub-message in the at least one sub-message includes the exclusive information of M terminal devices in the first terminal device group, where M is a natural number greater than or equal to 1.

7. The method according to any one of claims 1 to 6, characterized in that The method further comprises: The source network device receives a second message group sent by the target network device, where the second message group is used by the target network device to indicate a switching request response from all terminal devices in the first terminal device group.

8. The method according to claim 7, characterized in that The second message group is determined based on the access control judgment of the target network device, the first public information is used by the target network device to perform a first access control judgment, the second public information is used by the target network device to perform a second access control judgment, and the exclusive information of each terminal device in the first message group is used by the target network device to perform a third access control judgment.

9. The method according to any one of claims 1 to 8, characterized in that The method further comprises: The source network device sends first grouping information to each terminal device in the first terminal device set, where the first grouping information is used to indicate a first terminal device group to which the terminal device belongs.

10. The method according to claim 9, characterized in that The method further comprises: The source network device determines the first grouping information before receiving the measurement report of the terminal device, and the first grouping information is sent through signaling related to the measurement report.

11. The method according to claim 10, characterized in that The method further comprises: The source network device instructs any one terminal device in the first terminal device group to send a first measurement report according to the first grouping information, where the first measurement report is used to indicate measurement values ​​of all terminal devices in the first terminal device group.

12. The method according to claim 9, characterized in that The method further comprises: Before sending the first message group to the target network device, the source network device sends the first group information through separate signaling.

13. The method according to claim 9, characterized in that The method further comprises: The source network device sends the first grouping information according to the received switching request response, the switching request response is used to indicate whether each terminal device in the first terminal device group initiates switching, and the first grouping information is sent through the switching initiation message corresponding to the terminal device.

14. The method according to any one of claims 1 to 8, characterized in that The method further comprises: The source network device sends second grouping information by broadcasting, where the second grouping information is used for the terminal devices in the first terminal device set to determine the first terminal device group to which they belong; The source network device receives the grouping status reported by the terminal device.

15. The method according to any one of claims 1 to 14, characterized in that The source cell includes one or more first terminal device sets, and the one or more terminal device sets are determined according to one or more of the following information: A target cell corresponding to the terminal device in the source cell; The time when the terminal equipment in the source cell performs the cell switching.

16. The method according to any one of claims 1 to 15, characterized in that The one or more first terminal device groups are determined according to one or more of the following information: The geographical location of the terminal devices in the first terminal device set; A radio frequency range supported by terminal devices in the first terminal device set; The type of terminal devices in the first terminal device set; The capability of the terminal devices in the first terminal device set to access different access networks.

17. A cell switching method, characterized in that: Applied to handover from a source cell corresponding to a source network device to a target cell corresponding to a target network device, the method comprising: The target network device receives a first message group sent by the source network device, where the first message group is used to indicate a handover request of all terminal devices in a first terminal device group, where the first terminal device group is any one terminal device group in a first terminal device set that performs the cell handover, and the first terminal device set includes one or more of the first terminal device groups; The first message group includes first public information related to the source cell and / or the target cell and second public information related to the terminal devices in the first terminal device group.

18. The method according to claim 17, characterized in that The first message group includes at least one sub-message, and each sub-message in the at least one sub-message includes first identification information corresponding to the first terminal device group and second identification information corresponding to the source cell.

19. The method according to claim 17, characterized in that The first message group includes a first sub-message and a second sub-message, the first sub-message is a sub-message that is sent preferentially in the first message group, and the first sub-message includes the first public information and the second public information.

20. The method according to claim 19, characterized in that The first public information includes the cell configuration information of the source cell and the message attributes related to the first public information, the cell configuration information includes the second identification information corresponding to the source cell, and the second sub-message includes the message attributes related to the first public information and the second identification information in the first public information.

21. According to the method described in any one of claims 17-20, the first message group also includes exclusive information of all terminal devices in the first terminal device group, and the exclusive information is used by the target network device to determine the switching request of each terminal device in the first terminal device group.

22. The method according to claim 21, characterized in that The first message group includes at least one sub-message. If one sub-message in the at least one sub-message includes the terminal device-specific information, one sub-message in the at least one sub-message includes the exclusive information of M terminal devices in the first terminal device group, where M is a natural number greater than or equal to 1.

23. The method according to any one of claims 17 to 22, characterized in that The method further comprises: The target network device sends a second message group to the source network device, where the second message group is used by the target network device to indicate the switching request responses of all terminal devices in the first terminal device group.

24. The method according to claim 23, characterized in that The second message group is determined based on the access control judgment of the target network device, the first public information is used by the target network device to perform a first access control judgment, the second public information is used by the target network device to perform a second access control judgment, and the exclusive information of each terminal device in the first message group is used by the target network device to perform a third access control judgment.

25. The method according to any one of claims 17 to 24, characterized in that The source cell includes one or more first terminal device sets, and the one or more terminal device sets are determined according to one or more of the following information: A target cell corresponding to the terminal device in the source cell; The time when the terminal equipment in the source cell performs the cell switching.

26. The method according to any one of claims 17 to 25, characterized in that The one or more first terminal device groups are determined according to one or more of the following information: The geographical location of the terminal devices in the first terminal device set; A radio frequency range supported by terminal devices in the first terminal device set; The type of terminal devices in the first terminal device set; The capability of the terminal devices in the first terminal device set to access different access networks.

27. A method for cell switching, characterized in that: Applied to handover from a source cell corresponding to a source network device to a target cell corresponding to a target network device, the method comprises: The terminal device determines the first terminal device group to which it belongs, where the first terminal device group is any terminal device group in the first terminal device set that performs the cell switching, and the first terminal device set includes one or more of the first terminal device groups.

28. The method according to claim 27, characterized in that The method further comprises: The terminal device receives first grouping information sent by the source network device, where the first grouping information is used to indicate a first terminal device group to which the terminal device belongs.

29. The method according to claim 28, characterized in that The first grouping information is determined before the source network device receives the measurement report of the terminal device, and the first grouping information is sent through signaling related to the measurement report.

30. The method according to claim 29, characterized in that The method further comprises: The terminal device sends a first measurement report according to the instruction of the source network device, where the first measurement report is used to indicate the measurement values ​​of all terminal devices in the first terminal device group.

31. The method according to claim 28, characterized in that The method further comprises: The terminal device receives first packet information sent by the source network device through separate signaling, where the separate signaling is sent before the source network device sends a switching request to the target network device.

32. The method according to claim 28, characterized in that The method further comprises: The terminal device receives a switching initiation message sent by the source network device, the switching initiation message includes the first grouping information, the switching initiation message is determined according to a switching request response received by the source network device, and the switching request response is used to indicate whether each terminal device in the first terminal device group initiates a switch.

33. The method according to claim 27, characterized in that The method further comprises: The terminal device receives second grouping information through broadcasting, where the second grouping information is used by the terminal device to determine the first terminal device group to which it belongs; The terminal device reports the corresponding first terminal device group to the source network device.

34. The method according to any one of claims 27 to 33, characterized in that The one or more first terminal device groups are determined according to one or more information: The geographical location of the terminal devices in the first terminal device set; A radio frequency range supported by terminal devices in the first terminal device set; The type of terminal devices in the first terminal device set; The capability of the terminal devices in the first terminal device set to access different access networks.

35. A network device, characterized in that: The network device is a source network device, and the source network device includes: A determining unit, configured to determine a first terminal device group in a first terminal device set for performing cell switching, wherein the first terminal device set includes one or more of the first terminal device groups; A sending unit, configured to send a first message group to a target network device, wherein the first message group is used to indicate a switching request of all terminal devices in the first terminal device group; The first message group includes first public information related to a source cell corresponding to the source network device and / or a target cell corresponding to the target network device, and second public information related to terminal devices in the first terminal device group.

36. The network device according to claim 35, characterized in that The first message group includes at least one sub-message, and each sub-message in the at least one sub-message includes first identification information corresponding to the first terminal device group and second identification information corresponding to the source cell.

37. The network device according to claim 35, characterized in that: The first message group includes a first sub-message and a second sub-message, the first sub-message is a sub-message that is sent preferentially in the first message group, and the first sub-message includes the first public information and the second public information.

38. The network device according to claim 37, characterized in that: The first public information includes the cell configuration information of the source cell and the message attributes related to the first public information, the cell configuration information includes the second identification information corresponding to the source cell, and the second sub-message includes the message attributes related to the first public information and the second identification information in the first public information.

39. According to the network device described in any one of claims 35-38, the first message group also includes exclusive information of all terminal devices in the first terminal device group, and the exclusive information is used by the target network device to determine the switching request of each terminal device in the first terminal device group.

40. The network device according to claim 39, characterized in that: The first message group includes at least one sub-message. If one sub-message in the at least one sub-message includes the terminal device-specific information, one sub-message in the at least one sub-message includes the exclusive information of M terminal devices in the first terminal device group, where M is a natural number greater than or equal to 1.

41. The network device according to any one of claims 35 to 40, characterized in that: The source network device further includes: The first receiving unit is used to receive a second message group sent by the target network device, wherein the second message group is used for the target network device The device indicates a handover request response to all terminal devices in the first terminal device group.

42. The network device according to claim 41, characterized in that The second message group is determined based on the access control judgment of the target network device, the first public information is used by the target network device to perform a first access control judgment, the second public information is used by the target network device to perform a second access control judgment, and the exclusive information of each terminal device in the first message group is used by the target network device to perform a third access control judgment.

43. The network device according to any one of claims 35 to 42, characterized in that: The sending unit is further used to send first grouping information to each terminal device in the first terminal device set, where the first grouping information is used to indicate the first terminal device group to which the terminal device belongs.

44. The network device according to claim 43, characterized in that The determining unit is further configured to determine the first grouping information before receiving a measurement report of a terminal device, wherein the first grouping information is sent via signaling associated with the measurement report.

45. The network device according to claim 44, characterized in that The source network device further includes: An indication unit is used to indicate any terminal device in the first terminal device group to send a first measurement report according to the first grouping information, where the first measurement report is used to indicate the measurement values ​​of all terminal devices in the first terminal device group.

46. ​​The network device according to claim 43, characterized in that The sending unit is further configured to send the first grouping information through separate signaling before sending the first message group to the target network device.

47. The network device according to claim 43, characterized in that The sending unit is further used to send the first grouping information according to the received switching request response, the switching request response is used to indicate whether each terminal device in the first terminal device group initiates switching, and the first grouping information is sent through the switching initiation message corresponding to the terminal device.

48. The network device according to any one of claims 35 to 42, characterized in that: The sending unit is further used to send second grouping information by broadcasting, where the second grouping information is used for the terminal devices in the first terminal device set to determine the first terminal device group to which they belong; The source network device further includes: The second receiving unit is used to receive the grouping status reported by the terminal device.

49. The network device according to any one of claims 35 to 48, characterized in that: The source cell includes one or more first terminal device sets, and the one or more terminal device sets are determined according to one or more of the following information: A target cell corresponding to the terminal device in the source cell; The time when the terminal equipment in the source cell performs the cell switching.

50. The network device according to any one of claims 35 to 49, characterized in that: The one or more first terminal device groups are determined according to one or more of the following information: The geographical location of the terminal devices in the first terminal device set; A radio frequency range supported by terminal devices in the first terminal device set; The type of terminal devices in the first terminal device set; The capability of the terminal devices in the first terminal device set to access different access networks.

51. A network device, characterized in that: The network device is a target network device, and the target network device includes: A receiving unit, configured to receive a first message group sent by a source network device, wherein the first message group is used to indicate a switching request of all terminal devices in a first terminal device group, wherein the first terminal device group is any terminal device group in a first terminal device set that performs cell switching, and the first terminal device set includes one or more of the first terminal device groups; The first message group includes first public information related to a source cell corresponding to the source network device and / or a target cell corresponding to the target network device, and second public information related to terminal devices in the first terminal device group.

52. The network device according to claim 51, characterized in that The first message group includes at least one sub-message, and each sub-message in the at least one sub-message includes first identification information corresponding to the first terminal device group and second identification information corresponding to the source cell.

53. The network device according to claim 51, characterized in that The first message group includes a first sub-message and a second sub-message, the first sub-message is a sub-message that is sent preferentially in the first message group, and the first sub-message includes the first public information and the second public information.

54. The network device according to claim 53, characterized in that The first public information includes the cell configuration information of the source cell and the message attributes related to the first public information, the cell configuration information includes the second identification information corresponding to the source cell, and the second sub-message includes the message attributes related to the first public information and the second identification information in the first public information.

55. According to the network device described in any one of claims 51-54, the first message group also includes exclusive information of all terminal devices in the first terminal device group, and the exclusive information is used by the target network device to determine the switching request of each terminal device in the first terminal device group.

56. The network device according to claim 55, characterized in that The first message group includes at least one sub-message. If one sub-message in the at least one sub-message includes the terminal device-specific information, one sub-message in the at least one sub-message includes the exclusive information of M terminal devices in the first terminal device group, where M is a natural number greater than or equal to 1.

57. The network device according to any one of claims 51 to 56, characterized in that: The target network device also includes: A sending unit is used to send a second message group to the source network device, where the second message group is used by the target network device to indicate the switching request responses of all terminal devices in the first terminal device group.

58. The network device according to claim 57, characterized in that The second message group is determined based on the access control judgment of the target network device, the first public information is used by the target network device to perform a first access control judgment, the second public information is used by the target network device to perform a second access control judgment, and the exclusive information of each terminal device in the first message group is used by the target network device to perform a third access control judgment.

59. The network device according to any one of claims 51 to 58, characterized in that: The source cell includes one or more first terminal device sets, and the one or more terminal device sets are determined according to one or more of the following information: A target cell corresponding to the terminal device in the source cell; The time when the terminal equipment in the source cell performs the cell switching.

60. The network device according to any one of claims 51 to 59, characterized in that: The one or more first terminal device groups are determined according to one or more of the following information: The geographical location of the terminal devices in the first terminal device set; A radio frequency range supported by terminal devices in the first terminal device set; The type of terminal devices in the first terminal device set; The capability of the terminal devices in the first terminal device set to access different access networks.

61. A terminal device, characterized in that: include: A determination unit is used to determine the first terminal device group to which the terminal device belongs, and the terminal device performs a cell switch from a source cell corresponding to a source network device to a target cell corresponding to a target network device. The first terminal device group is any one terminal device group in a first terminal device set that performs the cell switch, and the first terminal device set includes one or more of the first terminal device groups.

62. The terminal device according to claim 61, characterized in that: The terminal device further includes: The first receiving unit is used to receive first grouping information sent by the source network device, where the first grouping information is used to indicate a first terminal device group to which the terminal device belongs.

63. The terminal device according to claim 62, characterized in that: The first grouping information is determined before the source network device receives the measurement report of the terminal device, and the first grouping information is sent through signaling related to the measurement report.

64. The terminal device according to claim 63, characterized in that: The terminal device further includes: The first sending unit is used to send a first measurement report according to the instruction of the source network device, where the first measurement report is used to indicate the measurement values ​​of all terminal devices in the first terminal device group.

65. The terminal device according to claim 62, characterized in that: The first receiving unit is further configured to receive first packet information sent by the source network device through separate signaling, where the separate signaling is sent before the source network device sends a switching request to the target network device.

66. The terminal device according to claim 62, characterized in that: The first receiving unit is also used to receive a switching initiation message sent by the source network device, the switching initiation message including the first grouping information, the switching initiation message is determined based on a switching request response received by the source network device, and the switching request response is used to indicate whether each terminal device in the first terminal device group initiates a switch.

67. The terminal device according to claim 61, characterized in that: The terminal device further includes: A second receiving unit, configured to receive second grouping information by broadcasting, wherein the second grouping information is used by the terminal device to determine the first terminal device group to which it belongs; The second sending unit is used to report the corresponding first terminal device group to the source network device.

68. The terminal device according to any one of claims 61-67, characterized in that: The one or more first terminal device groups are determined according to one or more information: The geographical location of the terminal devices in the first terminal device set; A radio frequency range supported by terminal devices in the first terminal device set; The type of terminal devices in the first terminal device set; The capability of the terminal devices in the first terminal device set to access different access networks.

69. A communication device, characterized in that: The invention comprises a memory and a processor, wherein the memory is used to store a program, and the processor is used to call the program in the memory to execute the method as claimed in any one of claims 1 to 34.

70. A device, characterized in that The invention comprises a processor, which is used to call a program from a memory to execute the method as claimed in any one of claims 1 to 34.

71. A chip, characterized in that: It comprises a processor, which is used to call a program from a memory, so that a device equipped with the chip executes a method as claimed in any one of claims 1 to 34.

72. A computer-readable storage medium, characterized in that A program is stored thereon, the program causing a computer to execute the method according to any one of claims 1 to 34.

73. A computer program product, characterized in that The method comprises a program which causes a computer to execute the method according to any one of claims 1 to 34.

74. A computer program, characterized in that The computer program causes a computer to execute the method according to any one of claims 1 to 34.

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