Location tracking method, terminal device and first network device

Abstract

The present application relates to a location tracking method, a terminal device, a first network device, a chip, a computer-readable storage medium, a computer program product, a computer program, and a communication system. The location tracking method comprises: a terminal device sends first information to a network device, wherein the first information is used for determining a first cell or a first area on which the terminal device camps, and the first area comprises at least one cell. The embodiments of the present application can reduce the network signaling overhead required for tracking a terminal device and the energy consumption of the terminal device.

Description

Location tracking method, terminal device and first network device Technical Field

[0001] This application relates to the field of communications, and more specifically, to a location tracking method, a terminal device, a first network device, a chip, a computer-readable storage medium, a computer program product, a computer program, and a communication system. Background Technology

[0002] In wireless communication systems, mobility management of terminal devices is a crucial component for ensuring network connectivity stability and user experience. Depending on the terminal device's Radio Resource Control (RRC) status, the network's tracking granularity and method differ. Reducing the network signaling overhead and power consumption of terminal devices during tracking is a problem that needs to be addressed. Summary of the Invention

[0003] This application provides a location tracking method, a terminal device, a first network device, a chip, a computer-readable storage medium, a computer program product, a computer program, and a communication system, which can reduce the network signaling overhead and power consumption of the terminal device required for tracking.

[0004] This application provides a location tracking method, including:

[0005] The terminal device sends first information to the network device; wherein the first information is used to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

[0006] This application provides a location tracking method, including:

[0007] The first network device receives first information sent by the terminal device; wherein the first information is used by the first network device to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

[0008] This application provides a terminal device, including:

[0009] The first communication unit is used to send first information to the network device; wherein the first information is used to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

[0010] This application provides a first network device, including:

[0011] The second communication unit is used to receive first information sent by the terminal device; wherein the first information is used by the first network device to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

[0012] This application provides a terminal device, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor invokes the computer program stored in the memory to cause the terminal device to execute the aforementioned location tracking method.

[0013] This application provides a first network device, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor invokes the computer program stored in the memory to cause the first network device to execute the aforementioned location tracking method.

[0014] This application provides a chip for implementing the above-described position tracking method.

[0015] Specifically, the chip includes a processor for calling a computer program from memory, causing a device equipped with the chip to perform the aforementioned position tracking method.

[0016] This application provides a computer-readable storage medium for storing a computer program that, when run by a device, causes the device to perform the aforementioned position tracking method.

[0017] This application provides a computer program product, including computer program instructions that cause a computer to execute the above-described position tracking method.

[0018] This application provides a computer program that, when run on a computer, causes the computer to execute the aforementioned position tracking method.

[0019] In this embodiment, the terminal device sends first information to the network device, enabling the network device to determine the first cell or first area where the terminal device is located based on the first information. This allows for tracking of the terminal device's location, ensuring the link reachability of the terminal device, and eliminating the need for complex signaling interactions. This reduces network signaling overhead and terminal device power consumption, thereby improving communication efficiency. Attached Figure Description

[0020] Figure 1 is a schematic diagram of a communication system according to an embodiment of this application.

[0021] Figure 2 is a schematic diagram of the basic process of LTM.

[0022] Figure 3 is a schematic flowchart of a position tracking method according to an embodiment of this application.

[0023] Figure 4 is a schematic flowchart of a location tracking method according to another embodiment of this application.

[0024] Figure 5 is a schematic block diagram of a terminal device according to an embodiment of this application.

[0025] Figure 6 is a schematic block diagram of a first network device according to an embodiment of the present application.

[0026] Figure 7 is a schematic block diagram of a communication device according to an embodiment of this application.

[0027] Figure 8 is a schematic block diagram of a chip according to an embodiment of this application.

[0028] Figure 9 is a schematic block diagram of a communication system according to an embodiment of this application. Detailed Implementation

[0029] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0030] The technical solutions of this application embodiment can be applied to various communication systems, such as: Long Term Evolution (LTE) systems, Advanced Long Term Evolution (LTE-A) systems, New Radio (NR) systems, evolution systems of NR systems, LTE-based access to unlicensed spectrum (LTE-U) systems, NR-based access to unlicensed spectrum (NR-U) systems, Non-Terrestrial Networks (NTN) systems, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (WiFi), 5th Generation (5G) systems, 6th Generation (6G) systems, or other communication systems.

[0031] Traditional communication systems typically support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communication but also, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, or vehicle-to-everything (V2X) communication. The embodiments of this application can also be applied to these communication systems.

[0032] In one implementation, the communication system in this application embodiment can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, or a standalone (SA) network deployment scenario.

[0033] In one embodiment, the communication system in this application can be applied to unlicensed spectrum, wherein the unlicensed spectrum can also be considered as shared spectrum; or, the communication system in this application can also be applied to licensed spectrum, wherein the licensed spectrum can also be considered as non-shared spectrum.

[0034] This application describes various embodiments in conjunction with network devices and terminal devices. The terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device, etc.

[0035] Terminal devices can be stations (STAs) in WLANs, cellular phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistant (PDA) devices, handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices, terminal devices in next-generation communication systems such as NR networks, or terminal devices in future evolved Public Land Mobile Network (PLMN) networks, etc.

[0036] In the embodiments of this application, the terminal device can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; it can also be deployed on water (such as ships); and it can also be deployed in the air (such as airplanes, balloons and satellites).

[0037] In the embodiments of this application, the terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical care, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home, etc.

[0038] By way of example and not limitation, in this embodiment, the terminal device can also be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not merely hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are feature-rich, large in size, and can achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those that focus on a specific type of application function and require the use of other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0039] In the embodiments of this application, the network device can be a device for communicating with mobile devices, such as an access point (AP) in a WLAN, an evolved Node B (eNB or eNodeB) in LTE, a relay station or access point, or a vehicle-mounted device, a wearable device, a network device (gNB) in an NR network, or a network device in a future evolved PLMN network or an NTN network, etc.

[0040] By way of example and not limitation, in this embodiment, the network device may have mobility characteristics; for example, the network device may be a mobile device. Optionally, the network device may be a satellite or a balloon station. For example, the satellite may be a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network device may also be a base station located on land, water, or other similar locations.

[0041] In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0042] Figure 1 illustrates an exemplary communication system 100. The communication system includes a network device 110 and two terminal devices 120. In one embodiment, the communication system 100 may include multiple network devices 110, and the coverage area of ​​each network device 110 may include other numbers of terminal devices 120; this embodiment does not limit the scope of the present application.

[0043] In one embodiment, the communication system 100 may also include other network entities such as a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF), which are not limited in this application.

[0044] It should be understood that devices with communication functions in the network / system of this application embodiment can be referred to as communication devices. Taking the communication system shown in Figure 1 as an example, the communication device may include network devices and terminal devices with communication functions. The network devices and terminal devices can be specific devices in this application embodiment, which will not be described in detail here. The communication device may also include other devices in the communication system, such as network controllers, mobility management entities, and other network entities. This application embodiment does not limit this.

[0045] It should be understood that the terms "system" and "network" are often used interchangeably in this document. The term "and / or" in this document merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0046] It should be understood that the term "instruction" mentioned in the embodiments of this application can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0047] In the description of the embodiments of this application, the term "correspondence" may indicate that there is a direct or indirect correspondence between two things, or that there is an association between two things, or that there is a relationship of instruction and being instructed, configuration and being configured, etc.

[0048] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies of the embodiments of this application are described below. The following relevant technologies are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and they all fall within the protection scope of the embodiments of this application.

[0049] (a) Layer 1 / L2-Triggered Mobility (LTM)

[0050] To reduce latency and signaling overhead during handover, related technologies support handover procedures triggered by Layer 1 (L1) / Layer 2 (L2), i.e., LTM. Figure 2 is a schematic diagram of the basic LTM process. As shown in Figure 2, LTM mainly includes the following steps:

[0051] 1. The UE reports the measurement results to the base station. These measurement results are Layer 3 (L3) measurement results. The base station then determines to initiate the LTM process and triggers candidate cell preparation.

[0052] 2. The base station sends an RRC message (i.e., an RRCReconfiguration message) containing LTM candidate cell configurations to the UE. The number of candidate cells can be one or more.

[0053] 3. The UE stores the LTM candidate cell configuration and sends a reconfiguration complete message (i.e., the RRCReconfigurationComplete message) back to the network;

[0054] 4. Before receiving the LTM cell handover command, the UE can perform uplink / downlink synchronization with the candidate cell in advance to reduce the interruption delay during the handover process.

[0055] 5. The UE performs L1 measurements on each candidate cell and reports the L1 measurement results to the network;

[0056] 6. The base station determines the target cell based on the L1 measurement results reported by the UE, and instructs the UE to hand over to the target cell through the Media Access Control Element (MAC CE);

[0057] 7. Depending on whether a valid TA exists for the target cell, the UE performs either RACH-less LTM or RACH-based LTM. If a valid TA exists for the target cell, the UE performs RACH-less LTM; otherwise, the UE performs RACH-based LTM and initiates a random access procedure to the target cell.

[0058] 8. The UE completes the LTM procedure by sending an RRC Reconfiguration Complete message to the target cell. For RACH-based LTM, the UE considers the LTM procedure to be successfully completed when the random access procedure is successfully completed; for RACH-less LTM, the UE considers the LTM procedure to be successfully completed when the network confirms that it has successfully received the first uplink data.

[0059] After completing one LTM process, the UE can continue to perform multiple subsequent LTM processes based on the candidate cell configuration received in step 2, that is, repeat the above steps 4-8.

[0060] (II) UE reachability under different RRC states

[0061] In modern wireless communication systems, user equipment (UE) mobility management is a crucial component for ensuring network connectivity stability and user experience. The granularity and methods of network tracking of the UE vary depending on its RRC status.

[0062] For terminals in connected state (RRC_CONNECTED), the network uses cells as the tracking granularity. This means that the network can know the exact location of the cell where the UE is currently camped and can monitor its connection status and mobility in real time. When the UE is in connected state, the network can use cell handover technology to ensure that the UE maintains continuous connection during movement.

[0063] For terminals in the inactive state (RRC_INACTIVE), the network tracks the UE's location within the Radio Access Network Notification Area (RNA). An RNA is a set of cells; the network only needs to know which RNA the UE is located in, not the exact cell location. When the network needs to contact an inactive UE, it first initiates a paging request within the RNA. Upon receiving the paging message, the UE returns to the connected state and establishes communication with the network. This approach reduces network signaling overhead and UE power consumption because inactive UEs do not need to frequently update their location.

[0064] As can be seen, in connected mode, precise tracking at the cell level ensures the continuity of uplink and downlink services. This is thanks to the UE's requirement to perform real-time measurements and measurement reporting to assist the network in efficient link management and mobility management. However, the link management process in connected mode requires significant energy consumption and signaling overhead. In inactive mode, although the UE can save energy through RNA-level tracking mechanisms, when uplink / downlink services arrive, the UE must first perform a state transition to return to connected mode before normal data transmission can occur. This state transition process introduces additional latency and signaling overhead, affecting service transmission efficiency. Therefore, reducing the network signaling overhead and energy consumption of tracking terminal devices is a problem that needs to be addressed.

[0065] Figure 3 is a schematic flowchart of a position tracking method according to an embodiment of this application. This method can optionally be applied to the system shown in Figure 1, but is not limited thereto. The method includes:

[0066] S310. The terminal device sends first information to the network device; wherein the first information is used to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

[0067] Optionally, the first region can be the tracking region / tracing area of ​​the terminal device, where the network device performs region-level tracking of the terminal device. For example, the terminal device can be configured within a region, which is predefined by the network device. Within this region, when the terminal device moves across cells, the network device may not be notified. When the terminal device moves outside the region, the network device needs to determine the region where the terminal device is camped. It can be understood that in this embodiment, the first information is used to determine the first cell or first region where the terminal device is camped, that is, it can support cell-level tracking or region-level tracking of the terminal device.

[0068] In one implementation, the first information includes at least one of a measurement report, reference signal, handover request, and handover confirmation message sent by the terminal device to the network device. The first information is used by the network device to perform cell-level location tracking of the terminal device. For example, the mobility of the terminal device is triggered by the network device, which continuously monitors the movement of the terminal device and triggers cell handover based on the first information.

[0069] In one implementation, the first information includes information about the source cell of the terminal device, and / or information about the first cell or the first area. Optionally, the source cell information may include the source cell's identification information, and the first cell information may include the first cell's identification information. The aforementioned identification information may be, for example, a Physical Cell Identifier (PCI), a Cell Radio Network Temporary Identifier (C-RNTI), a candidate cell identifier, etc. The first information can be used by the network equipment of the source cell to determine the first cell or the first area where the terminal device camps.

[0070] For example, the terminal device may send first information to the network device of the source cell, including information about the first cell or the first area, so that the network device of the source cell can determine the first cell or the first area where the terminal device is camped.

[0071] For example, a terminal device may send first information to a first network device in a target cell (i.e., the first cell) or a target area (i.e., the first area), including information about the source cell, so that the first network device can notify a second network device in the source cell that the terminal device has moved to the first cell or the first area.

[0072] For example, a terminal device may send first information to any network device, including information about the source cell and information about the first cell or the first area, so that the network device receiving the first information can notify the network device of the source cell that the terminal device has moved to the first cell or the first area.

[0073] Optionally, when a terminal device camps on a first cell or a first area, the network equipment in that first cell or area may not establish a connection between the terminal device and the core network. In other words, the user plane and / or control plane between the radio access network and the core network (RAN-CN) for that terminal device remain on the source side. By sending first information, the terminal device enables the source cell maintaining the RAN-CN connection to know the terminal device's latest location information, ensuring the terminal device's uplink / downlink reachability. This means that when uplink / downlink services arrive, a path switch can be performed promptly for normal data transmission.

[0074] Optionally, when a terminal device camps on a first cell or a first area, the network device of the source cell can transfer the access layer (AS) context of the terminal device to the network device of the first cell or the first area.

[0075] As can be seen, the above location tracking method sends first information from the terminal device to the network device, enabling the network device to determine the first cell or first area where the terminal device is located based on the first information, thereby tracking the location of the terminal device, ensuring the link reachability of the terminal device, and eliminating the need for complex signaling interactions. This reduces network signaling overhead and terminal device power consumption, and improves communication efficiency.

[0076] In some embodiments, the terminal device sends first information to the network device, including: in a first mode, the terminal device sends first information to the network device; wherein, the first mode is one of multiple modes under RRC connected state (RRC_connected) or inactive state (RRC_inactive), or one of multiple RRC states.

[0077] In one implementation, the first mode is one of two modes under RRC connection state. For example, the aforementioned multiple modes include the first mode and the second mode (such as the normal mode) under RRC connection state. Compared to the second mode, the terminal device in the first mode does not require complex mobility management / link management procedures. Optionally, in the second mode, the terminal device can maintain continuous connection during movement through cell handover. In the first mode, when the terminal device moves from the source cell to the first cell or the first area, it sends first information to enable the network equipment in the source cell to determine the first cell or the first area where the terminal device is located.

[0078] In one implementation, the first mode is one of two modes under the RRC inactive state. For example, the aforementioned multiple modes include a first mode and a second mode (such as a normal mode) under the RRC inactive state. Compared to the second mode, the terminal device in the first mode can quickly recover to the normal data transmission mode. Optionally, in the second mode, the network device tracks the location of the terminal device within the RNA range and initiates paging within the RNA range when it needs to contact the terminal device. In the first mode, when the terminal device moves from the source cell to the first cell or the first area, it sends first information to enable the network device in the source cell to determine the first cell or the first area where the terminal device is located, and can respond quickly when the service arrives.

[0079] In one implementation, the first mode is one of several RRC states. Exemplarily, the multiple RRC states include an RRC inactive state, an RRC connected state, and a compromise state between the RRC inactive and RRC connected states. Optionally, the first mode can be a compromise state between the RRC inactive and RRC connected states. Compared to the RRC inactive state, a terminal device in the first mode can quickly recover to normal data transmission mode; compared to the RRC connected state, a terminal device in the first mode does not require complex mobility / link management procedures.

[0080] Optionally, the first mode described above can be called the lightweight mode.

[0081] In some embodiments, the first information includes a first message sent to the network device of the source cell of the terminal device, the first message being used to determine whether the terminal device has left the source cell or is preparing to move to the first cell.

[0082] Optionally, the first message is a termination message (Bye message) sent by the terminal device to the source cell.

[0083] In some embodiments, the first message includes information about a first cell. For example, the information about the first cell may include identification information of the first cell, such as PCI or candidate cell identifier.

[0084] For example, when a terminal device performs a cell handover in the first mode, it first sends a Bye message to the source cell, notifying the source cell that the terminal device is about to perform a cell handover. The Bye message may contain information about the target cell (i.e., the first cell), such as the target cell's PCI. After receiving the Bye message, the source cell can assist the target cell in establishing a communication link with the UE based on the information in the Bye message. For example, if the target cell is not a candidate cell, the source cell's network device transfers the terminal device's AS context to the target cell's network device; if the target cell is a candidate cell, the source cell's network device does not need to transfer the terminal device's AS context to the target cell's network device.

[0085] In some embodiments, the first information includes a second message sent to the network device of the first cell, the second message being used to determine whether the terminal device leaves or enters the first cell from the source cell.

[0086] In some embodiments, the second message includes a greeting message (Hi message) sent by the terminal device to the target cell.

[0087] For example, when a terminal device accesses a first cell, it sends a Hi message to the first cell to notify the first cell of its arrival. The Hi message may contain information about the source cell, such as the source cell's PCI, C-RNTI, etc. After receiving the Hi message, the first cell can quickly establish a communication link with the terminal device based on the information in the Hi message to achieve downlink reachability. For example, the network device of the first cell may request the AS context of the terminal device from the network device of the source cell, and / or inform the UE of its access.

[0088] In some embodiments, the terminal device sends first information to the network device, including: the terminal device sending a first message to the network device of the source cell, wherein the first message is used to determine that the terminal device has left the source cell; and if the terminal device does not receive an acknowledgment message for the first message, the terminal device sending a second message to the network device of the first cell.

[0089] Optionally, if the terminal device receives an acknowledgment message for the first message, the terminal device does not need to send a second message to the network device of the first cell.

[0090] For example, the first message is a Bye message and the second message is a Hi message. When the terminal device determines to perform a cell handover, it sends a Bye message to the source cell and listens for downlink confirmation information on the network side. If the terminal device receives downlink confirmation information before leaving the source cell, it does not need to send a Hi message to the target cell when accessing it; otherwise, the terminal device needs to send a Hi message to the target cell when accessing it.

[0091] In some embodiments, the second message includes a message sent to the first cell when the terminal device moves from the source cell to the first cell or when the terminal device moves across regions to the first cell.

[0092] For example, the second message includes a first RRC message for triggering the first RRC procedure.

[0093] For example, the first RRC procedure includes an RRC reconstruction procedure.

[0094] In some embodiments, sending first information to a network device by a terminal device includes: when the terminal device moves from a second area to a first cell in a first area, sending a first RRC message to the network device of the first cell. That is, the first RRC message is a message sent by the terminal device when it moves across areas to the first cell.

[0095] For example, a terminal device can freely perform cell reselection within the area where the source cell is located without sending location update messages to the network device, which can significantly reduce network signaling overhead and terminal device power consumption. When the terminal device moves across areas to the first cell, it triggers the first process by sending the first RRC message. The network device of the first cell can determine the source cell and obtain the AS context of the terminal device based on the first RRC message, assisting the terminal device in completing the RRC reconstruction process.

[0096] In some embodiments, the second message includes a third message periodically sent by the terminal device to the network device, such as a third message periodically sent to the network device of the currently camped cell. By periodically sending the third message to the network device of the currently camped cell, the network devices of each cell (including the first cell) can promptly confirm that the terminal device has entered the cell, thereby obtaining the AS context of the terminal device in a timely manner.

[0097] In some embodiments, the third message includes a second RRC message or a MAC CE. Optionally, the second RRC message may be a first RRC message used to trigger the first RRC process, such as an RRC message that triggers the RRC reconstruction process, or it may be other RRC messages.

[0098] In some embodiments, the second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

[0099] Optionally, the source cell information can be used by the network device of the first cell to determine the source cell in order to obtain the AS context of the terminal device.

[0100] Optionally, the identity identifier of the terminal device can be used by the network device of the first cell to determine the identity of the terminal device. In some cases, the source cell can be determined based on the identity (e.g., if the first cell is a candidate cell) in order to obtain the AS context of the terminal device.

[0101] Optionally, the identifier used to characterize whether the terminal device has moved across regions can be used by the network equipment in the first cell to determine whether to trigger the RRC reconstruction process. For example, if the terminal device has moved across regions, the RRC reconstruction process is triggered; if the terminal device has not moved across regions, the RRC reconstruction process is not triggered. Exemplarily, the identifier can be 0 to indicate no cross-regional movement and 1 to indicate cross-regional movement; or 1 to indicate no cross-regional movement and 0 to indicate cross-regional movement.

[0102] For example, in the case where the second message includes a Hi message, the Hi message contains information about the source cell of the terminal device.

[0103] For example, when the second message includes a first RRC message, the first RRC message may include information about the source cell and / or an identifier used to characterize whether the terminal device has moved across regions.

[0104] For example, when the second message includes a periodically triggered third message, the third message may include at least one of the following: information of the source cell, the identity of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

[0105] It can be understood that the second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier indicating whether the terminal device has moved across regions. Specifically, the second message may include any one or any combination of these three elements. The specific form can be determined based on protocol agreements, system agreements, application requirements, communication scenarios, etc. For the sake of brevity, not all possible forms will be listed here.

[0106] In some embodiments, if the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

[0107] In some embodiments, when the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device. For example, the network device in the first cell can determine the source cell of the terminal device based on the terminal device's identity, without needing to carry the source cell information in the second message.

[0108] In some embodiments, the first region, i.e. the tracking region, includes at least one candidate cell.

[0109] For example, the first region mentioned above can be a cell set, a centralized unit (CU), a distributed unit (DU), an RNA, or a tracking area (TA).

[0110] To facilitate understanding of the above technical solutions, corresponding examples are provided below for specific application scenarios.

[0111] Application Example 1

[0112] In this application example, cell-level UE location tracking is supported in Lite mode. UE mobility in Lite mode is triggered by either the network or the UE itself.

[0113] If mobility in lightweight mode is network-triggered, the mobility management procedures in related technologies are reused. This means that the network continuously monitors the UE's movement and triggers cell handover when necessary. The network coordinates the handover process between the source and target cells through measurement reports / uplink reference signals, handover requests, and confirmation messages.

[0114] If mobility in lightweight mode is triggered by the UE, the UE needs to send a Bye / Hi message to help the source and target cells determine the cell where the UE is currently camped. Specifically, the Bye message is used to notify the source cell that the UE is about to leave its current cell. The Hi message is used to notify the target cell that the UE is accessing its current cell.

[0115] One approach is for the UE to send a Bye message to the source cell.

[0116] When a UE performs a cell handover in Lite mode, it first sends a Bye message to the source cell, notifying it that a handover is imminent. The Bye message may contain information about the target cell, such as its PCI or candidate cell identifier. Upon receiving the Bye message, the source cell can assist the target cell in establishing a communication link with the UE based on the information in the Bye message; for example, the source cell may transfer the UE's AS context to the target cell. In one implementation, if the target cell is a candidate cell and already has the UE's AS context, the source cell does not need to transfer the UE's AS context to the target cell.

[0117] Another method is for the UE to send a Hi message to the target cell.

[0118] When a UE accesses a target cell, it sends a Hi message to the target cell to notify it of its arrival. The Hi message may contain information about the source cell, such as the source cell's PCI and C-RNTI. Upon receiving the Hi message, the target cell can quickly establish a communication link with the UE based on the information in the Hi message, achieving downlink reachability. For example, the target cell may request the UE's AS context from the source cell and / or inform it of the UE's access. In one implementation, if the target cell is a candidate cell, the Hi message does not need to contain source cell information.

[0119] Another approach is for the UE to send a Bye message to the source cell and, under certain circumstances, send a Hi message to the target cell.

[0120] When a UE determines to perform a cell handover, it sends a Bye message to the source cell and listens for downlink confirmation information from the network side. If the UE receives downlink confirmation information before leaving the source cell, it does not need to send a Hi message to the target cell when accessing it; otherwise, the UE needs to send a Hi message to the target cell when accessing it.

[0121] In the above scheme, the target cell does not need to establish a connection with the core network. That is, the user plane and / or control plane connections between the RAN and CN remain on the source side. The source cell maintaining the RAN-CN connection only needs to know the UE's latest location information to ensure the UE's downlink reachability. When the UE needs to switch to normal mode in a certain cell, the target cell / source cell / CN then performs a path handover. This avoids frequent path handover processes and saves signaling overhead between the RAN and CN.

[0122] This application example proposes a cell-level UE tracking mechanism that achieves uplink / downlink reachability in Lite mode through Bye / Hi message exchange between the network and the UE. This scheme not only ensures uplink / downlink reachability of the UE in Lite mode, but also reduces network signaling overhead and UE power consumption, thereby improving communication efficiency.

[0123] Application Example 2

[0124] In this application example, UE location tracking at the cell level is supported in lightweight mode.

[0125] In Lite mode, the network can choose to track the UE at the region level. Specifically, the UE can be configured within a region, which is predefined by the network. Within this region, the network does not need to be notified when the UE performs cell reselection. Only when the UE moves outside the region will the UE trigger an RRC reconstruction process to inform the network of the UE's current location information.

[0126] The network configures a specific tracking area for the UE, which consists of at least one cell. In one implementation, this area consists of at least one candidate cell; that is, the candidate cell used for cell handover in normal mode naturally becomes the tracking area in Lite mode. Within this area, the UE can freely perform cell reselection without sending location update messages to the network. This significantly reduces network signaling overhead and UE power consumption because the UE does not need to perform location updates frequently.

[0127] When the UE moves outside the tracking area, and / or periodically, the UE triggers a first RRC procedure, including the UE sending a first RRC message to the network. In one implementation, the first procedure is an RRC reconstruction procedure.

[0128] For example, after receiving the first RRC message, the network will determine the source cell and obtain the UE's AS context based on the information in the first RRC message (e.g., the source cell's PCI / C-RNTI, and an identifier indicating whether it has moved out of the area range), assisting the UE in completing the connection reconstruction process. Optionally, the source cell is the cell in which the UE last entered the normal mode connected state.

[0129] For example, after receiving the first RRC message, the network only needs to synchronize the UE's current location information with the source cell. In this implementation, the target cell does not need to request the UE context from the source cell, as the network has already synchronized the UE context with neighboring cells within a certain range.

[0130] This application example proposes a region-level UE tracking mechanism. By configuring specific tracking regions, it enables mobility management and downlink reachability in Lite mode. This scheme not only significantly reduces network signaling overhead and UE power consumption (i.e., the UE does not need to frequently report location information), but also ensures UE mobility and downlink reachability both inside and outside the configured region, improving communication efficiency.

[0131] Figure 4 is a schematic flowchart of a position tracking method according to an embodiment of this application. This method can optionally be applied to the system shown in Figure 1, but is not limited thereto. The method includes at least a portion of the following:

[0132] S410, The first network device receives first information sent by the terminal device; wherein, the first information is used by the first network device to determine the first cell or the first area where the terminal device is camped, and the first area includes at least one cell.

[0133] Optionally, the first network device may be the source cell of the terminal device or the network device of the aforementioned first cell or first area.

[0134] In one implementation, the first network device is a network device in a first cell or a first area. The first network device can send other information to a second network device (e.g., the network device of the source cell) to enable the second network device to determine that the terminal device is camped in the first cell or the first area. Optionally, the first network device can also request the AS context of the terminal device from the second network device. Optionally, the first network device may not establish a connection between the terminal device and the core network. That is, the user plane and / or control plane between the radio access network and the core network (RAN-CN) for the terminal device remain on the source side. By sending the first information, the terminal device enables the source cell maintaining the RAN-CN connection to know the latest location information of the terminal device, which can ensure the uplink / downlink reachability of the terminal device. That is, when uplink / downlink services arrive, path switching can be performed in a timely manner to carry out normal data transmission.

[0135] In one implementation, the first network device is the network device of the source cell of the terminal device. The first network device can determine that the terminal device is camped in the first cell or the first area based on the first information, and transfer the AS context of the terminal device to the second network device (e.g., the network device of the first cell or the first area).

[0136] For specific examples of the method executed by the first network device in this application embodiment, please refer to the relevant description of the network device (e.g., the network device of the source cell, the network device of the first cell) in the above-described method executed by the terminal device. For the sake of brevity, it will not be repeated here.

[0137] In some embodiments, the first information is information transmitted in a first mode; wherein the first mode is one of a variety of modes in an RRC connected state or an inactive state, or one of a variety of RRC states.

[0138] In some embodiments, the first information includes a first message, which is used to determine that the terminal device leaves the cell under the first network device or is preparing to move to the first cell. That is, the first network device is the network device of the source cell, and the terminal device sends the first message to the source cell so that the source cell determines that the terminal device has moved to the first cell or the first area.

[0139] In some embodiments, the first message includes information about the first cell.

[0140] In some embodiments, the location tracking method further includes: a first network device sending second information to a network device in a first cell; the second information includes the access layer AS context of the terminal device.

[0141] In some embodiments, the location tracking method further includes: a first network device sending an acknowledgment message to a terminal device in response to a first message.

[0142] Optionally, the confirmation message is used by the terminal device to determine whether it needs to send a second message, such as a Hi message, to the network device of the first cell.

[0143] In some embodiments, the first network device is the network device of the first cell, and the first information includes a second message, which is used by the first network device to determine whether the terminal device leaves the source cell or enters the first cell.

[0144] In some embodiments, the second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

[0145] In some embodiments, if the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

[0146] In some embodiments, when the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device.

[0147] In some embodiments, the second message includes a first RRC message for triggering a first RRC procedure.

[0148] In some embodiments, the first RRC procedure includes an RRC reconstruction procedure.

[0149] In some embodiments, the second message includes a third message that the terminal device periodically sends to the network device.

[0150] In some embodiments, the third message includes a second RRC message or a MAC CE.

[0151] In some embodiments, the location tracking method further includes:

[0152] The first network device sends third information to the network device of the source cell of the terminal device; the third information is used to request the AS context of the terminal device.

[0153] In some embodiments, the location tracking method further includes:

[0154] The first network device sends fourth information to the network device of the source cell of the terminal device; wherein the fourth information is used by the network device of the source cell to determine the first cell or first area where the terminal device is camped.

[0155] In some embodiments, the first region includes at least one candidate cell.

[0156] Figure 5 is a schematic block diagram of a terminal device 500 according to an embodiment of the present application. The terminal device 500 may include:

[0157] The first communication unit 510 is used to send first information to the network device; wherein the first information is used to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

[0158] In some embodiments, the first communication unit is used to send first information to the network device in a first mode; wherein the first mode is one of a variety of modes in an RRC connected state or an inactive state, or one of a variety of RRC states.

[0159] In some embodiments, the first information includes a first message sent to the network device of the source cell of the terminal device, the first message being used to determine whether the terminal device has left the source cell or is preparing to move to the first cell.

[0160] In some embodiments, the first message includes information about the first cell.

[0161] In some embodiments, the first information includes a second message sent to the network device of the first cell, the second message being used to determine whether the terminal device leaves or enters the first cell from the source cell.

[0162] In some embodiments, the second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

[0163] In some embodiments, if the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

[0164] In some embodiments, when the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device.

[0165] In some embodiments, the first communication unit 510 is used for:

[0166] Send a first message to the network device in the source cell; wherein, the first message is used to determine that the terminal device has left the source cell;

[0167] If no confirmation message is received for the first message, a second message is sent to the network equipment of the first cell.

[0168] In some embodiments, the second message includes a first RRC message for triggering a first RRC procedure.

[0169] In some embodiments, the first RRC procedure includes an RRC reconstruction procedure.

[0170] In some embodiments, the first communication unit 510 is used for:

[0171] In the case of moving from the second area to the first cell in the first area, a first RRC message is sent to the network device in the first cell.

[0172] In some embodiments, the second message includes a third message that the terminal device periodically sends to the network device.

[0173] In some embodiments, the third message includes a second RRC message or a MAC CE.

[0174] In some embodiments, the first region includes at least one candidate cell.

[0175] The terminal device 500 of this application embodiment can implement the corresponding functions of the terminal device in the foregoing method embodiments. The processes, functions, implementation methods, and beneficial effects of each module (sub-module, unit, or component, etc.) in the terminal device 500 can be found in the corresponding descriptions in the above method embodiments, and will not be repeated here. It should be noted that the functions described for each module (sub-module, unit, or component, etc.) in the terminal device 500 of the application embodiment can be implemented by different modules (sub-modules, units, or components, etc.) or by the same module (sub-module, unit, or component, etc.).

[0176] Figure 6 is a schematic block diagram of a first network device 600 according to an embodiment of the present application. The first network device 600 may include:

[0177] The second communication unit 610 is used to receive first information sent by the terminal device; wherein the first information is used by the first network device to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

[0178] In some embodiments, the first information is information transmitted in a first mode; wherein the first mode is one of multiple modes in an RRC connected state or an inactive state, or one of multiple RRC states.

[0179] In some embodiments, the first information includes a first message, which is used to determine whether the terminal device is leaving a cell under the first network device or is preparing to move to the first cell.

[0180] In some embodiments, the first message includes information about the first cell.

[0181] In some embodiments, the second communication unit 610 is further configured to:

[0182] Send the second information to the network equipment in the first cell; the second information includes the AS context of the terminal device.

[0183] In some embodiments, the second communication unit 610 is further configured to:

[0184] Send an acknowledgment message to the terminal device in response to the first message.

[0185] In some embodiments, the first network device is the network device of the first cell, and the first information includes a second message, which is used by the first network device to determine whether the terminal device leaves the source cell or enters the first cell.

[0186] In some embodiments, the second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

[0187] In some embodiments, if the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

[0188] In some embodiments, when the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device.

[0189] In some embodiments, the second message includes a first RRC message for triggering a first RRC procedure.

[0190] In some embodiments, the first RRC procedure includes an RRC reconstruction procedure.

[0191] In some embodiments, the second message includes a third message that the terminal device periodically sends to the network device.

[0192] In some embodiments, the third message includes a second RRC message or a MAC CE.

[0193] In some embodiments, the second communication unit 610 is further configured to:

[0194] Send third information to the network device of the source cell of the terminal device; the third information is used to request the AS context of the terminal device.

[0195] In some embodiments, the second communication unit 610 is further configured to:

[0196] Send fourth information to the network device of the source cell of the terminal device; wherein the fourth information is used by the network device of the source cell to determine the first cell or first area where the terminal device is camped.

[0197] In some embodiments, the first region includes at least one candidate cell.

[0198] The first network device 600 of this application embodiment can implement the corresponding functions of the first network device in the foregoing method embodiments. The processes, functions, implementation methods, and beneficial effects of each module (sub-module, unit, or component, etc.) in the first network device 600 can be found in the corresponding descriptions in the above method embodiments, and will not be repeated here. It should be noted that the functions described for each module (sub-module, unit, or component, etc.) in the first network device 600 of the application embodiment can be implemented by different modules (sub-modules, units, or components, etc.) or by the same module (sub-module, unit, or component, etc.).

[0199] Figure 7 is a schematic structural diagram of a communication device 700 according to an embodiment of this application. The communication device 700 includes a processor 710, which can call a computer program from a memory to enable the communication device 700 to implement the method in the embodiment of this application.

[0200] In one embodiment, the communication device 700 may further include a memory 720. The processor 710 can retrieve computer programs from the memory 720 to enable the communication device 700 to implement the methods described in the embodiments of this application.

[0201] The memory 720 can be a separate device independent of the processor 710, or it can be integrated into the processor 710.

[0202] In one embodiment, the communication device 700 may further include a transceiver 730, which the processor 710 may control to communicate with other devices. Specifically, it may send information or data to other devices or receive information or data sent by other devices.

[0203] The transceiver 730 may include a transmitter and a receiver. The transceiver 730 may further include antennas, and the number of antennas may be one or more.

[0204] In one embodiment, the communication device 700 may be the first network device in the embodiments of this application, and the communication device 700 may implement the corresponding processes implemented by the first network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0205] In one embodiment, the communication device 700 may be a terminal device in the embodiments of this application, and the communication device 700 may implement the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0206] Figure 8 is a schematic structural diagram of a chip 800 according to an embodiment of this application. The chip 800 includes a processor 810, which can call computer programs from memory to implement the methods in the embodiments of this application.

[0207] In one embodiment, chip 800 may further include memory 820. Processor 810 can retrieve computer programs from memory 820 to implement the methods executed by the terminal device or the first network device in this embodiment.

[0208] The memory 820 can be a separate device independent of the processor 810, or it can be integrated into the processor 810.

[0209] In one embodiment, the chip 800 may further include an input interface 830. The processor 810 can control the input interface 830 to communicate with other devices or chips; specifically, it can acquire information or data sent by other devices or chips.

[0210] In one embodiment, the chip 800 may further include an output interface 840. The processor 810 can control the output interface 840 to communicate with other devices or chips; specifically, it can output information or data to other devices or chips.

[0211] In one implementation, the chip can be applied to the first network device in the embodiments of this application, and the chip can implement the corresponding processes implemented by the first network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0212] In one embodiment, the chip can be applied to the terminal device in the embodiments of this application, and the chip can implement the corresponding processes implemented by the terminal device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0213] The chips used in the first network device and the terminal device can be the same chip or different chips.

[0214] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0215] The processors mentioned above can be general-purpose processors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), or other programmable logic devices, transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processors mentioned above can be microprocessors or any conventional processor.

[0216] The aforementioned memory can be volatile memory or non-volatile memory, or a combination of both. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM).

[0217] It should be understood that the above-described memory is exemplary and not a limiting description. For example, the memory in the embodiments of this application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM), etc. That is to say, the memory in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0218] Figure 9 is a schematic block diagram of a communication system 900 according to an embodiment of this application. The communication system 900 includes a terminal device 910 and a first network device 920.

[0219] Specifically, the terminal device 910 can be used to implement the corresponding functions implemented by the terminal device in the above method, and the first network device 920 can be used to implement the corresponding functions implemented by the first network device in the above method. For the sake of brevity, further details are omitted here.

[0220] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. This computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0221] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply 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 this application.

[0222] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0223] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A position tracking method, comprising: The terminal device sends first information to the network device; wherein the first information is used to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

2. The method according to claim 1, wherein, The terminal device sends first information to the network device, including: In the first mode, the terminal device sends first information to the network device; wherein the first mode is one of multiple modes under the Radio Resource Management (RRC) connected state or inactive state, or one of multiple RRC states.

3. The method according to claim 1 or 2, wherein, The first information includes a first message sent to the network device of the source cell of the terminal device, the first message being used to determine whether the terminal device has left the source cell or is preparing to move to the first cell.

4. The method according to claim 3, wherein, The first message includes information about the first cell.

5. The method according to any one of claims 1-4, wherein, The first information includes a second message sent to the network device of the first cell, the second message being used to determine whether the terminal device leaves or enters the first cell from the source cell.

6. The method according to claim 5, wherein, The second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

7. The method according to claim 5 or 6, wherein, If the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

8. The method according to any one of claims 5-7, wherein, If the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device.

9. The method according to any one of claims 5-8, wherein, The terminal device sends first information to the network device, including: The terminal device sends a first message to the network device of the source cell; wherein, the first message is used to determine that the terminal device has left the source cell; If the terminal device does not receive a confirmation message for the first message, the terminal device sends the second message to the network device of the first cell.

10. The method according to any one of claims 5-8, wherein, The second message includes a first RRC message for triggering the first RRC procedure.

11. The method according to claim 10, wherein, The first RRC process includes an RRC reconstruction process.

12. The method according to claim 10 or 11, wherein, The terminal device sends first information to the network device, including: When the terminal device moves from the second region to the first cell in the first region, it sends the first RRC message to the network device of the first cell.

13. The method according to any one of claims 5-12, wherein, The second message includes a third message that the terminal device periodically sends to the network device.

14. The method according to claim 13, wherein, The third message includes a second RRC message or a Media Intervention Control Layer Control Unit (MAC CE).

15. The method according to any one of claims 1-14, wherein, The first region includes at least one candidate cell.

16. A position tracking method, comprising: A first network device receives first information sent by a terminal device; wherein the first information is used by the first network device to determine a first cell or a first area where the terminal device is camped, and the first area includes at least one cell.

17. The method according to claim 16, wherein, The first information is information transmitted in a first mode; wherein, the first mode is one of multiple modes in the RRC connected state or inactive state, or one of multiple RRC states.

18. The method according to claim 16 or 17, wherein, The first information includes a first message, which is used to determine whether the terminal device leaves the cell under the first network device or is preparing to move to the first cell.

19. The method according to claim 18, wherein, The first message includes information about the first cell.

20. The method according to claim 18 or 19, wherein, The method further includes: The first network device sends second information to the network device of the first cell; the second information includes the access layer AS context of the terminal device.

21. The method according to any one of claims 18-20, wherein, The method further includes: The first network device sends an acknowledgment message to the terminal device in response to the first message.

22. The method according to claim 16 or 17, wherein, The first network device is the network device of the first cell, and the first information includes a second message, which is used by the first network device to determine whether the terminal device leaves the source cell or enters the first cell.

23. The method according to claim 22, wherein, The second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

24. The method according to claim 22 or 23, wherein, If the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

25. The method according to any one of claims 22-24, wherein, If the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device.

26. The method according to any one of claims 22-25, wherein, The second message includes a first RRC message for triggering the first RRC procedure.

27. The method according to claim 26, wherein, The first RRC process includes an RRC reconstruction process.

28. The method according to any one of claims 22-27, wherein, The second message includes a third message that the terminal device periodically sends to the network device.

29. The method according to claim 28, wherein, The third message includes a second RRC message or a MAC CE.

30. The method according to any one of claims 22-29, wherein, The method further includes: The first network device sends third information to the network device of the source cell of the terminal device; the third information is used to request the AS context of the terminal device.

31. The method according to any one of claims 22-30, wherein, The method further includes: The first network device sends fourth information to the network device of the source cell of the terminal device; wherein, the fourth information is used by the network device of the source cell to determine the first cell or first area where the terminal device is camped.

32. The method according to any one of claims 16-31, wherein, The first region includes at least one candidate cell.

33. A terminal device, comprising: A first communication unit is configured to send first information to a network device; wherein the first information is configured to determine a first cell or a first area where the terminal device is camped, and the first area includes at least one cell.

34. The terminal device according to claim 33, wherein, The first communication unit is used to send first information to the network device in a first mode; wherein the first mode is one of multiple modes under RRC connected state or inactive state, or one of multiple RRC states.

35. The terminal device according to claim 33 or 34, wherein, The first information includes a first message sent to the network device of the source cell of the terminal device, the first message being used to determine whether the terminal device is leaving the source cell or preparing to move to the first cell.

36. The terminal device according to claim 35, wherein, The first message includes information about the first cell.

37. The terminal device according to any one of claims 33-36, wherein, The first information includes a second message sent to the network device of the first cell, the second message being used to determine whether the terminal device leaves or enters the first cell from the source cell.

38. The terminal device according to claim 37, wherein, The second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

39. The terminal device according to claim 37 or 38, wherein, If the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

40. The terminal device according to any one of claims 37-39, wherein, If the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device.

41. The terminal device according to any one of claims 37-40, wherein, The first communication unit is used for: Send a first message to the network device of the source cell; wherein the first message is used to determine that the terminal device has left the source cell; If no confirmation message is received for the first message, the second message is sent to the network device of the first cell.

42. The terminal device according to any one of claims 37-40, wherein, The second message includes a first RRC message for triggering the first RRC procedure.

43. The terminal device according to claim 42, wherein, The first RRC process includes an RRC reconstruction process.

44. The terminal device according to claim 42 or 43, wherein, The first communication unit is used for: In the case of moving from the second region to the first cell in the first region, the first RRC message is sent to the network device of the first cell.

45. The terminal device according to any one of claims 37-44, wherein, The second message includes a third message that the terminal device periodically sends to the network device.

46. ​​The terminal device according to claim 45, wherein, The third message includes a second RRC message or a MAC CE.

47. The terminal device according to any one of claims 33-46, wherein, The first region includes at least one candidate cell.

48. A first network device, comprising: The second communication unit is used to receive first information sent by the terminal device; wherein the first information is used by the first network device to determine the first cell or first area where the terminal device is camped, and the first area includes at least one cell.

49. The first network device according to claim 48, wherein, The first information is information transmitted in a first mode; wherein, the first mode is one of multiple modes in the RRC connected state or inactive state, or one of multiple RRC states.

50. The first network device according to claim 48 or 49, wherein, The first information includes a first message, which is used to determine whether the terminal device leaves the cell under the first network device or is preparing to move to the first cell.

51. The first network device according to claim 50, wherein, The first message includes information about the first cell.

52. The first network device according to claim 50 or 51, wherein, The second communication unit is also used for: Send second information to the network device of the first cell; the second information includes the AS context of the terminal device.

53. The first network device according to any one of claims 50-52, wherein, The second communication unit is also used for: Send an acknowledgment message to the terminal device in response to the first message.

54. The first network device according to claim 48 or 49, wherein, The first network device is the network device of the first cell, and the first information includes a second message, which is used by the first network device to determine whether the terminal device leaves the source cell or enters the first cell.

55. The first network device according to claim 54, wherein, The second message includes at least one of the following: information about the source cell of the terminal device, the identity identifier of the terminal device, and an identifier used to characterize whether the terminal device has moved across regions.

56. The first network device according to claim 54 or 55, wherein, If the first cell is not a candidate cell, the second message includes information about the source cell of the terminal device.

57. The first network device according to any one of claims 54-56, wherein, If the first cell is a candidate cell, the second message does not include information about the source cell of the terminal device.

58. The first network device according to any one of claims 54-57, wherein, The second message includes a first RRC message for triggering the first RRC procedure.

59. The first network device according to claim 58, wherein, The first RRC process includes an RRC reconstruction process.

60. The first network device according to any one of claims 54-59, wherein, The second message includes a third message that the terminal device periodically sends to the network device.

61. The first network device according to claim 60, wherein, The third message includes a second RRC message or a MAC CE.

62. The first network device according to any one of claims 54-61, wherein, The second communication unit is also used for: Send third information to the network device of the source cell of the terminal device; the third information is used to request the AS context of the terminal device.

63. The first network device according to any one of claims 54-62, wherein, The second communication unit is also used for: Send fourth information to the network device of the source cell of the terminal device; wherein the fourth information is used by the network device of the source cell to determine the first cell or first area where the terminal device is camped.

64. The first network device according to any one of claims 48-63, wherein, The first region includes at least one candidate cell.

65. A terminal device, comprising: A transceiver, a processor, and a memory, wherein the memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to invoke the computer program stored in the memory to cause the terminal device to perform the method as described in any one of claims 1 to 15.

66. A first network device, comprising: A transceiver, a processor, and a memory, wherein the memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to invoke the computer program stored in the memory to cause the first network device to perform the method as described in any one of claims 16 to 32.

67. A chip, comprising: A processor for calling a computer program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1 to 15.

68. A chip, comprising: A processor for calling a computer program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 16 to 32.

69. A computer-readable storage medium for storing a computer program that, when run by a device, causes the device to perform the method as claimed in any one of claims 1 to 15.

70. A computer-readable storage medium for storing a computer program that, when run by a device, causes the device to perform the method as described in any one of claims 16 to 32.

71. A computer program product comprising computer program instructions that cause a computer to perform the method as described in any one of claims 1 to 15.

72. A computer program product comprising computer program instructions that cause a computer to perform the method as described in any one of claims 16 to 32.

73. A computer program that causes a computer to perform the method as described in any one of claims 1 to 15.

74. A computer program that causes a computer to perform the method as described in any one of claims 16 to 32.

75. A communication system, comprising: A terminal device for performing the method as described in any one of claims 1 to 15; A first network device is configured to perform the method as described in any one of claims 16 to 32.

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