Communication method and communication apparatus

Abstract

The application provides a communication method and a communication device. The method comprises: a first access network device determining that the signal quality of a terminal device in a source cell is lower than a preset threshold; the first access network device determining a target cell and controlling the terminal device to switch to the target cell. Alternatively, the first access network device determining that a first wireless resource accessed by the terminal device in the source cell does not support a first network slice corresponding to a first session requested by the terminal device to establish or activate; the first access network device determining a target cell and controlling the terminal device to switch to the target cell; and the second wireless resource of the target cell supporting the first network slice. Thus, when the signal quality of the terminal device in the source cell is not good or the first wireless resource of the source cell does not support the network slice corresponding to the session requested by the terminal device to establish or activate, the first access network device can timely determine the target cell for the terminal device, thereby improving the user experience.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless communication, and more particularly, to a communication method and a communication apparatus. BACKGROUND

[0002] Currently, it is known that a terminal device can perform cell or frequency reselection based on a radio access technology frequency selection priority (RFSP) index allocated by a core network. One RFSP index value can be associated with a set of parameters for cell / frequency camping or reselection. In one implementation, an access network device can query the terminal device-specific cell / frequency camping or reselection parameters according to the authorized RFSP index, and then send them to the terminal device. After the terminal device enters an idle state, it can access a frequency band with high priority according to these parameters.

[0003] However, the terminal device needs to wait until the current service is completed and enters the idle state, and then performs cell / frequency reselection according to the radio parameters corresponding to the RFSP index. When the signal quality of the current cell is not good, or the network slice corresponding to the session requested to be established or activated is not supported by the radio resources of the current accessed cell, the terminal device cannot be switched to a suitable cell in time, which may result in a decline in the communication quality of the current session of the terminal device, or the session requested to be established or activated cannot be responded in time, and the user experience is not good. SUMMARY

[0004] The present application provides a communication method and a communication apparatus to control the terminal device to switch to a suitable cell in time, so as to facilitate improving the communication quality of the terminal device in a short time, or responding to the session requested to be established or activated by the terminal device in time, and improving the user experience.

[0005] The method of the first aspect to the third aspect provided below may, for example, be performed by a first access network device, or may also be performed by a component (such as a circuit, a chip, or a chip system, etc.) configured in the first access network device. The present application does not limit this. Hereinafter, the method provided by the present application is described with the first access network device as the execution subject for the purpose of understanding and description.

[0006] In a first aspect, a communication method is provided. The method comprises: determining, by a first access network device, that a signal quality of a terminal device in a source cell is lower than a preset threshold, the source cell being a cell served by the first access network device; determining, by the first access network device, a target cell from at least one neighboring cell of the source cell, according to a first network slice corresponding to a first session activated by the terminal device in the source cell and network slices supported by the at least one neighboring cell respectively, the target cell supporting the first network slice; and controlling, by the first access network device, the terminal device to perform handover to the target cell.

[0007] Based on the above technical solution, when the signal quality of the terminal device in the source cell is poor, the first access network device serving the source cell can determine a target cell for the terminal device according to the network slice corresponding to the session activated by the terminal device in the source cell, the network slices supported by the at least one neighboring cell respectively, and the frequency range corresponding to each network slice, and control the terminal device to perform handover to the target cell. Therefore, the terminal device can perform handover to the target cell with better signal quality in a timely manner when the signal quality is poor and there is a target cell that can be switched to, so that measures can be taken in a timely manner when the communication quality is poor, instead of waiting until the terminal device completes the current service and then enters an idle state to perform cell reselection. Therefore, the communication quality of the terminal device can be improved in a short time, which is beneficial to improving user experience.

[0008] In order to obtain better signal quality, the target cell determined by the first access network device for the terminal device supports the first network slice on the one hand, and the signal quality meets the preset threshold on the other hand.

[0009] In combination with the first aspect, in some possible implementation manners of the first aspect, the target cell is a cell served by a second access network device.

[0010] That is, the terminal device can perform handover to the target cell with better signal quality as long as it performs intra-site handover.

[0011] In combination with the first aspect, in some possible implementation manners of the first aspect, the target cell is a cell served by a second access network device.

[0012] Here, the second access network device is different from the first access network device. That is, the source cell and the target cell are different sites. The terminal device needs to perform handover between access network devices. That is, the terminal device needs to perform cross-site handover.

[0013] If the cell served by the first access network device only includes the source cell of the terminal device, or the first access network device does not find a suitable cell as the target cell in the intra-station neighboring cells, the target cell can be found in the inter-station neighboring cells. It should be understood that if the inter-station neighboring cells are multiple, the multiple inter-station neighboring cells can be cells served by one or more access network devices. The one or more access network devices include the second access network device.

[0014] In an implementation manner, the first access network device can preferentially find the target cell in the neighboring cell served by the first access network device, and secondarily find the target cell in the neighboring cell served by the other access network device, so as to avoid the complex flow of access network device switching.

[0015] Optionally, the method further includes: determining, by the first access network device, the radio measurement parameter according to the first network slice, the network slices supported by the at least one neighboring cell respectively, and the radio resources corresponding to the supported network slices; and sending, by the first access network device, the radio measurement parameter to the terminal device, where the radio measurement parameter is used for the terminal device to measure the signal quality of the neighboring cell, and the measurement of the signal quality of the neighboring cell by the terminal device is used for the determination of the target cell.

[0016] If the first access network device is to find the target cell from the neighboring cell served by the other access network device, the target cell can be selected in combination with the signal quality of each inter-station neighboring cell. Therefore, the first access network device can determine the radio measurement parameter according to the first network slice, the network slices supported by the neighboring cell, and the radio resources corresponding to each network slice. The terminal device can measure the signal quality of the neighboring cell based on the radio measurement parameter, so that the first access network device determines the target cell according to the measurement result.

[0017] Optionally, the method further includes: sending, by the first access network device, a request message to the second access network device, where the request message carries the identification information of the first session and the identification information of the first network slice; receiving, by the first access network device, a radio resource control (RRC) parameter for switching from the second access network device; and sending, by the first access network device, the RRC parameter to the terminal device.

[0018] After the first access network device determines the target cell for the terminal device, the first access network device can send a request message to a second access network device serving the target cell to request RRC parameters for handover. In one possible design, the request message is a handover request message. Correspondingly, the second access network device can send the RRC parameters to the first access network device through a handover request acknowledgement (handover request ACK) message. The RRC parameters can be carried in an RRC message container in the handover request ACK message, so that the first access network device can transparently transmit the RRC parameters to the terminal device.

[0019] In a second aspect, a communication method is provided, including: determining, by a first access network device, that a first wireless resource accessed by a terminal device in a source cell does not support a first network slice corresponding to a first session requested by the terminal device to establish or to activate, the source cell being a cell served by the first access network device; determining, by the first access network device, a target cell, a second wireless resource of the target cell supporting the first network slice; and controlling, by the first access network device, the terminal device to hand over to the target cell.

[0020] Based on the above technical solutions, when the first session requested by the terminal device to establish or to activate cannot be supported by the wireless resource of the source cell, the first access network device serving the source cell can determine a target cell for the terminal device according to the first network slice corresponding to the first session, the network slices supported by each of at least one neighboring cell, and the wireless resources corresponding to the network slices, and control the terminal device to hand over to the target cell. Therefore, the terminal device can be handed over to the target cell in a timely manner when the first session requested to establish or to activate cannot be supported by the wireless resource of the source cell and there is a target cell available for handover, without having to enter an idle state for cell reselection after the terminal device completes the current service. Thus, the session request of the terminal device can be responded to in a timely manner, and the first session can be activated within a short time, which is beneficial to improving user experience.

[0021] To obtain better signal quality, the target cell determined by the first access network device for the terminal device supports the first network slice and has a signal quality satisfying a preset threshold.

[0022] Optionally, the second wireless resource also supports a network slice corresponding to a second session of the terminal device, the second session including an activated session or a deactivated session.

[0023] That is, the target cell not only supports the first network slice, but also supports other network slices, such as a network slice corresponding to the activated session or the deactivated session, thereby avoiding service interruption of the activated or deactivated session due to switching of the cell, or the need to re-switch the cell due to the target cell not supporting.

[0024] With reference to the second aspect, in some possible implementation of the second aspect, the first access network device determines the target cell, including: the first access network device determines a target frequency range, and determines the target cell based on the target frequency range.

[0025] The target frequency range is a frequency range supporting the first network slice. The target frequency range can be selected from the target frequency range indicated by the first wireless resource first, and then from other frequency ranges.

[0026] Optionally, the first access network device determines the target frequency range, including: the first access network device determines the target frequency range according to a network slice allowed to be accessed by the terminal device, the first network slice, and a frequency range corresponding to the first network slice.

[0027] It should be understood that the network slice allowed to be accessed by the terminal device can be determined according to a network slice requested by the terminal device, a network slice subscribed by the terminal device, and a network slice supported by a tracking area or a registration area where the terminal device is located. The network slice subscribed by the terminal device can be obtained by an access and mobility management network element from a unified data management network element. Therefore, the network slice allowed to be accessed by the terminal device can be determined by the access and mobility management network element, and notified to the first access network device, so as to facilitate the first access network device to determine the target frequency range.

[0028] Optionally, the first access network device determines the target frequency range, including: the first access network device determines the target frequency range according to a network slice requested by the terminal device, a network slice available to the terminal device according to a subscription, a network slice supported by a tracking area or a registration area where the terminal device is located, the first network slice, and a frequency range of the first network slice.

[0029] The network slice available to the terminal device according to the subscription can be, for example, notified to the first access network device by a core network device such as an access and mobility management network element.

[0030] When the terminal device is in a home network, the network slice available to the terminal device according to the subscription can refer to a network slice subscribed by the terminal device; when the terminal device is in a visited network, the network slice available to the terminal device according to the subscription can refer to a network slice of the visited network corresponding to the network slice subscribed by the terminal device.

[0031] Therefore, the two implementation manners of determining the target frequency range listed above are alternative.

[0032] In a possible implementation form of the second aspect, the first access network device determines the target cell from intra-station neighboring cells supporting the target frequency range, the intra-station neighboring cells being other cells than the source cell from a plurality of cells served by the first access network device.

[0033] Optionally, the first access network device controls the terminal device to handover to the target cell, including that the first access network device sends a radio resource management (RRM) configuration message to the terminal device, the RRM configuration message being used to control the terminal device to handover to the target cell.

[0034] That is, the first access network device can find the target cell in the intra-station neighboring cells based on the pre-determined target frequency range. If the first access network device finds the target cell in the intra-station neighboring cells, the terminal device can handover to the target cell supporting the first network slice as long as performing intra-station handover.

[0035] In a possible implementation form of the second aspect, the first access network device determines the target cell from inter-station neighboring cells supporting the target frequency range, the inter-station neighboring cells being cells other than the cells served by the first access network device from neighboring cells of the source cell.

[0036] Optionally, the first access network device determines the target cell from the inter-station neighboring cells supporting the target frequency range includes that the first access network device determines whether there is a first cell supporting the target frequency range in the inter-station neighboring cells of the source cell; the first access network device determines whether the first cell supports the first network slice in the case that there is the first cell; the first access network device determines the first cell as the target cell in the case that the first cell supports the first network slice.

[0037] If the cells served by the first access network device only include the source cell of the terminal device, or the first access network device does not find a suitable cell in the intra-station neighboring cells as the target cell, the first access network device can directly find the target cell in the inter-station neighboring cells. It should be understood that if the inter-station neighboring cells are multiple, the multiple inter-station neighboring cells can be one or more cells served by one or more access network devices. The one or more access network devices include a second access network device.

[0038] In an implementation, the first access network device can prioritize finding the target cell in the neighboring cell served by the first access network device based on the target frequency range, and secondarily prioritize finding the target cell in the neighboring cell served by the other access network device, to avoid a complex procedure of access network device handover.

[0039] In addition, the target frequency range can prioritize the frequency range indicated by the first radio resource. That is, the first access network device can prioritize finding the target cell in the neighboring cell served by the first access network device based on the first frequency range, and secondarily prioritize finding the target cell in the neighboring cell served by the other access network device based on the second frequency range. In any one of the above procedures, as long as the first access network device finds the target cell, the subsequent step of finding the target cell can not be performed.

[0040] Optionally, the method further includes: determining, by the first access network device, the radio measurement parameter according to the target frequency range; sending, by the first access network device, the radio measurement parameter to the terminal device, the radio measurement parameter being used for the terminal device to measure the signal quality of the neighboring cell; and the measurement of the signal quality of the neighboring cell by the terminal device is used for the determination of the target cell.

[0041] If the first access network device is to find the target cell in the neighboring cell served by the other access network device, the target cell can be further selected in combination with the signal quality of each inter-site neighboring cell. Therefore, the first access network device can determine the radio measurement parameter according to the first network slice, the target frequency range, the network slice supported by each of the at least one neighboring cell, and the radio resource corresponding to each network slice. The terminal device can measure the signal quality of the neighboring cell based on the radio measurement parameter, so that the first access network device determines the target cell according to the measurement result.

[0042] Optionally, the method further includes: sending, by the first access network device, a request message to the second access network device serving the target cell, the request message carrying the identification information of the first session and the identification information of the first network slice; receiving, by the first access network device, the RRC parameter for handover from the second access network device; and sending, by the first access network device, the RRC parameter to the terminal device.

[0043] After the first access network device determines the target cell for the terminal device, the first access network device can send a request message to the second access network device serving the target cell to request RRC parameters for handover. In one possible design, the request message is a handover request message. Correspondingly, the second access network device can send the RRC parameters to the first access network device through a handover request acknowledgement message. The RRC parameters can be carried in an RRC message container in the handover request acknowledgement message, so that the first access network device can transparently transmit the RRC parameters to the terminal device.

[0044] With reference to the first aspect or the second aspect, the RRC parameters are associated with the first network slice, network slices supported by the second access network device, and wireless resources corresponding to the network slices supported by the second access network device. The network slices supported by the second access network device refer to network slices supported by at least one cell served by the second access network device.

[0045] The RRC parameters can be determined by the second access network device according to the first network slice corresponding to the first session to be switched in, and wireless resources corresponding to the first network slice in a cell served by the second access network device, so that the second access network device can determine which cell to switch to.

[0046] In a third aspect, a communication method is provided, including: determining, by a first access network device, that a first wireless resource through which a terminal device accesses a source cell does not support a first network slice of a first session requested by the terminal device to establish or activate, the source cell being a cell served by the first access network device; and sending, by the first access network device, an RRC connection release message to the terminal device to release an RRC connection with the terminal device. The first access network device releases the RRC connection with the terminal device, and the currently activated session is deactivated.

[0047] Based on the above technical solutions, the first access network device can actively release the RRC connection with the terminal device in a case where the first wireless resource through which the terminal device accesses does not support the first network slice of the first session requested to establish or activate, so that the terminal device can quickly enter an idle state and initiate cell reselection. Instead of waiting until the current service is completed before entering the idle state. Therefore, the terminal device can timely perform cell reselection in a case where the first session requested to establish or activate is not supported by the wireless resource of the source cell, without having to wait until the terminal device completes the current service before entering the idle state to perform cell reselection. Thus, the terminal device can timely respond to the session request and activate the first session in a short time, which is beneficial to improving user experience.

[0048] In a possible implementation of the third aspect, the method further includes: determining, by the first access network device, a target frequency range according to the allowed network slice and the frequency range corresponding to the first network slice; or, determining, by the first access network device, the target frequency range according to the network slice requested by the terminal device, the network slice that can be used by the terminal device according to a subscription, the network slice supported by a tracking area or a support area where the terminal device is located, the first network slice, and the frequency range corresponding to the first network slice; determining, by the first access network device, a radio parameter according to the target frequency range and the network slice supported by each of the at least one neighboring cell and the radio resource corresponding to the supported network slice, the radio parameter being used for cell reselection of the terminal device; and sending, by the first access network device, the radio parameter to the terminal device.

[0049] In order to facilitate the terminal device to quickly find a suitable cell to access, the first access network device can send a radio parameter to the terminal device, so that the terminal device performs cell reselection based on the radio parameter, thereby facilitating the terminal device to quickly select a cell to re-access.

[0050] In combination with the second aspect or the third aspect, in a possible implementation, the method further includes: receiving, by the first access network device, a message for requesting to establish or activate the first session from the terminal device.

[0051] The terminal device can request to establish or activate the first session in the source cell in different scenarios.

[0052] The first possible case is that the terminal device can be a terminal device that accesses the network after being powered on, or can be a terminal device that initiates a registration request because it moves to a new tracking area that does not belong to an original registration area, or can be a terminal device that periodically updates registration to the network.

[0053] In this case, the first access network device receives the message for requesting to establish or activate the first session from the terminal device, including: receiving, by the first access network device, a registration request message from the terminal device, the registration request message carrying identification information of the first session for requesting to establish or activate.

[0054] The second possible case is that the terminal device has established one or more sessions in the source cell served by the first access network device, but the one or more sessions are in a deactivated state, and the terminal device and the first access network device each reserve a context of the one or more sessions, and a user plane connection of the one or more sessions is not activated. Or, the terminal device expects to establish one or more new sessions in the source cell.

[0055] In this case, the first access network device receives a message from the terminal device for requesting establishment or activation of the first session, including: the first access network device receives a session request message from the terminal device, and the session request message carries identification information of the first session for requesting establishment or activation.

[0056] The third possible case is that the terminal device is in an RRC connected state with the first access network device. The terminal device intends to establish one or more new sessions or activate one or more sessions in the source cell.

[0057] In this case, the first access network device receives a message from the terminal device for requesting establishment or activation of the first session, including: the first access network device receives a session establishment request message from the terminal device, and the session establishment request message carries identification information of the first session for requesting establishment, or carries identification information of the first network slice corresponding to the first session; or the first access network device receives a session activation request message from the terminal device, and the session activation request message carries identification information of the first session for requesting activation, or carries identification information of the first network slice corresponding to the first session.

[0058] It should be understood that the several possible cases listed above are only examples provided for understanding the method of the embodiments of the present application, and should not constitute any limitation on the present application.

[0059] In a fourth aspect, a communication apparatus is provided, including various modules or units for performing the method in any possible implementation manner of the first aspect to the third aspect.

[0060] In a fifth aspect, a communication apparatus is provided, including a processor. The processor is coupled with a memory and is configured to execute instructions or data in the memory to implement the method in any possible implementation manner of the first aspect to the third aspect. Optionally, the communication apparatus further includes the memory. Optionally, the communication apparatus further includes a communication interface, and the processor is coupled with the communication interface.

[0061] In an implementation manner, the communication apparatus is an access network device, such as the first access network device in the first aspect to the third aspect. When the communication apparatus is an access network device, the communication interface can be a transceiver, or an input / output interface.

[0062] In another implementation manner, the communication apparatus is a chip configured in an access network device. The access network device can be, for example, the first access network device in the first aspect to the third aspect. When the communication apparatus is a chip configured in an access network device, the communication interface can be an input / output interface.

[0063] Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0064] In a sixth aspect, a processor is provided, comprising an input circuit, an output circuit and a processing circuit. The processing circuit is configured to receive a signal via the input circuit and transmit a signal via the output circuit, so that the processor performs the method in any possible implementation of the first aspect to the third aspect.

[0065] In a specific implementation process, the processor can be one or more chips, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, a gate circuit, a flip-flop, various logic circuits and the like. The input signal received by the input circuit can be received and input by, for example but not limited to, a receiver, the output signal output by the output circuit can be output to and transmitted by, for example but not limited to, a transmitter, and the input circuit and the output circuit can be the same circuit which is used as the input circuit and the output circuit at different times respectively. The embodiments of the present application do not limit the specific implementation of the processor and various circuits.

[0066] In a seventh aspect, a processing apparatus is provided, comprising a processor and a memory. The processor is configured to read instructions stored in the memory, and can receive a signal via a receiver and transmit a signal via a transmitter to perform the method in any possible implementation of the first aspect to the third aspect.

[0067] Optionally, the processor can be one or more, and the memory can be one or more.

[0068] Optionally, the memory can be integrated with the processor, or the memory can be separately arranged from the processor.

[0069] In a specific implementation process, the memory can be a non-transitory memory, for example, a read only memory (ROM), which can be integrated on the same chip as the processor, or can be separately arranged on different chips. The embodiments of the present application do not limit the type of memory and the arrangement of the memory and the processor.

[0070] It should be understood that the related data interaction process, for example, the process of transmitting the indication information can be the process of outputting the indication information from the processor, and the process of receiving the capability information can be the process of receiving the input capability information by the processor. Specifically, the data output by the processor can be output to the transmitter, and the input data received by the processor can come from the receiver. The transmitter and the receiver can be collectively referred to as a transceiver.

[0071] The processing device in the seventh aspect can be one or more chips. The processor in the processing device can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc. When implemented by software, the processor can be a general-purpose processor, which is implemented by reading software codes stored in a memory. The memory can be integrated in the processor or exist independently outside the processor.

[0072] In an eighth aspect, a computer program product is provided, which includes a computer program (also referred to as code or instructions), which, when executed, causes a computer to perform the method in any possible implementation of the first aspect to the third aspect.

[0073] In a ninth aspect, a computer-readable storage medium is provided, which stores a computer program (also referred to as code or instructions), which, when executed on a computer, causes the computer to perform the method in any possible implementation of the first aspect to the third aspect.

[0074] In a tenth aspect, a communication system is provided, which includes the first access network device and the terminal device as described above. Optionally, the communication system further includes the second access network device as described above. BRIEF DESCRIPTION OF DRAWINGS

[0075] Figure 1 is a schematic diagram of a network architecture suitable for the method provided in the embodiments of the present application;

[0076] Figures 2 to 10 is a schematic flowchart of the communication method provided in the embodiments of the present application;

[0077] Figure 11 and Figure 12 is a schematic block diagram of the communication device provided in the embodiments of the present application;

[0078] Figure 13 is a structural schematic diagram of the access network device provided in the embodiments of the present application. DETAILED DESCRIPTION

[0079] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0080] The technical solutions provided in the present application can be applied to various communication systems, for example, a 5th Generation (5G) mobile communication system or a new radio access technology (NR). The 5G mobile communication system can include non-standalone (NSA) and / or standalone (SA).

[0081] The technical solutions provided in the present application can also be applied to machine type communication (MTC), Long Term Evolution-machine (LTE-M), device to device (D2D) network, machine to machine (M2M) network, internet of things (IoT) network or other network. The IoT network may, for example, include a vehicle network. In the vehicle network system, the communication mode is collectively referred to as vehicle to X (V2X, X can represent any thing), for example, the V2X can include vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication or vehicle to network (V2N) communication, etc.

[0082] The technical solutions provided in the present application can also be applied to future communication systems, such as a 6th Generation mobile communication system, etc. The present application does not limit this.

[0083] Figure 1 is a schematic diagram of a network architecture suitable for the method provided in the embodiments of the present application. As shown in Figure 1As shown, the network architecture is, for example, the 5G system (5GS) defined in the 3rd Generation Partnership Project (3GPP) technical specification (TS) 23.501. The network architecture can be divided into two parts: an access network (AN) and a core network (CN). Among them, the access network can be used to implement wireless access related functions, and the core network mainly includes the following several key logical network elements: access and mobility management network element, session management network element, user plane network element, policy control network element and unified data management network element, etc.

[0084] The following is a brief introduction to each network element shown in the figure: Figure 1

[0085] 1. User equipment (UE): can be referred to as terminal equipment, 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.

[0086] ​The terminal device can be a device that provides voice / data connectivity to a user, such as a handheld device with wireless connection function, a vehicle-mounted device, and the like. Currently, some examples of terminals can be a mobile phone, a pad, a computer (such as a notebook computer, a palm computer, and the like) with wireless transceiver function, a mobile internet device (MID), 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, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5G network, or a terminal device in a future evolved public land mobile network (PLMN), and the like.

[0087] In addition, the terminal device can also be a terminal device in an Internet of things (IoT) system. IoT is an important part of the future development of information technology, and its main technical feature is to connect objects through communication technology and network, so as to realize the intelligent network of man-machine interconnection and object-object interconnection. IoT technology can achieve massive connection, deep coverage, and terminal power saving through, for example, narrowband (NB) technology.

[0088] In addition, the terminal device can also include a smart printer, a train detector, a gas station sensor, and the like, and the main functions include collecting data (for some terminal devices), receiving control information and downlink data of a network device, and transmitting electromagnetic waves to transmit uplink data to the network device.

[0089] 2、Access network (AN): The access network can provide network access functions for authorized users in a specific area, and can use different quality transmission tunnels according to the level of the user, the demand of the service, etc. The access network can be an access network using different access technologies. There are two types of current wireless access technologies: 3GPP access technology (such as the wireless access technology used in 3G, 4G or 5G systems) and non-3GPP (non-3GPP) access technology. The 3GPP access technology refers to the access technology that conforms to the 3GPP standard specification, for example, the access network device in the 5G system is called the next generation Node Base station (gNB). The non-3GPP access technology refers to the access technology that does not conform to the 3GPP standard specification, for example, the air interface technology represented by the access point (AP) in the wireless fidelity (WiFi).

[0090] The access network that implements the access network function based on the wireless communication technology can be referred to as a radio access network (RAN). The radio access network can manage wireless resources and provide access services for terminal devices, and then complete the forwarding of control signals and user data between the terminal and the core network.

[0091] The radio access network may, for example, include but is not limited to: a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (such as a home evolved NodeB or home Node B, HNB), a baseband unit (BBU), an AP in a WiFi system, a wireless relay node, a wireless backhaul node, a transmission point (TP) or a transmission and reception point (TRP), etc. It can also be a gNB or a transmission point (TRP or TP) in a 5G (such as NR) system, one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node that constitutes a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU), or a base station in a next-generation communication 6G system, etc. The embodiments of the present application do not limit the specific technology and specific device form of the radio access network device.

[0092] An access network can serve a cell. A terminal device can communicate with the cell through a transmission resource (e.g., a frequency domain resource, or a spectrum resource) allocated by an access network device.

[0093] 3. Access and mobility management network element: mainly used for registration, mobility management, tracking area update process of a terminal in a mobile network, the access and mobility management network element terminates non-access stratum (NAS) messages, completes registration management, connection management, and reachability management, allocates a tracking area list (TA list) and mobility management, and transparently routes session management (SM) messages to a session management network element. In a 5G communication system, the access and mobility management network element can be an access and mobility management function (AMF).

[0094] 4. Session management network element: mainly used for session management in a mobile network, such as session establishment, modification, and release. Specific functions include allocating an Internet protocol (IP) address for a terminal, selecting a user plane network element that provides message forwarding functions, and the like. In a 5G communication system, the session management network element can be a session management function (SMF).

[0095] 5. User plane network element: mainly responsible for processing user messages, such as forwarding, charging, lawful interception, and the like. The user plane network element can also include a protocol data unit (PDU) session anchor (PSA). In a 5G communication system, the user plane network element can be a user plane function (UPF).

[0096] 6. Data network (DN): can be used to provide data transmission services for terminal devices. The data network can be a public data network (PDN) network, such as the Internet, and the like, or a local access data network (LADN), such as a network of a mobile edge computing (MEC) node; it can also be a third-party service network, an IP multi-media service network, and the like.

[0097] 7. Policy control network element: A unified policy framework used to guide network behavior, providing policy rule information for control plane functional network elements (such as AMF, SMF, etc.).

[0098] It includes user subscription data management functions, policy control functions, billing policy control functions, and quality of service (QoS) control. In 5G communication systems, the policy control network element can be a policy control function (PCF).

[0099] It should be noted that in actual networks, PCFs may also be divided into multiple entities according to layers or functions, such as global PCFs and PCFs within slices, or session management PCFs (SM-PCFs) and access management PCFs (AM-PCFs).

[0100] 8. Network Slice Selection Element: Primarily used to select the appropriate network slice for the services of terminal devices. In 5G communication systems, the network slice selection element can be the network slice selection function (NSSF).

[0101] 9. Unified Data Management Network Element: Used to store user data, such as subscription information, authentication / authorization information, etc. In 5G communication systems, the unified data management network element can be unified data management (UDM).

[0102] exist Figure 1 In the network architecture shown, network elements can communicate with each other through the interfaces shown in the diagram. For example, terminal equipment and AMF can communicate through interface N1; RAN and AMF can communicate through interface N2, which can be used for sending non-access stratum (NAS) messages; RAN and UPF can communicate through interface N3, which can be used for transmitting user plane data; the interfaces connecting RAN to the core network (i.e., interfaces N2 and N3) are collectively referred to as Ng interfaces; SMF and UPF can communicate through interface N4, which can be used to transmit information such as tunnel identification information connected by N3, data buffer indication information, and downlink data notification messages; UPF and DN can communicate through interface N6, which can be used for transmitting user plane data. It should be understood that the communication relationships between the above network elements and interfaces are merely examples and should not constitute any limitation on this application. This application does not preclude the possibility of defining other interfaces in future protocols for communication between the above network elements or between other network elements.

[0103] It should be understood that the network architecture applied to the embodiments of the present application is only a network architecture described from the perspective of the traditional point-to-point architecture and the service-oriented architecture, and the network architecture applicable to the embodiments of the present application is not limited thereto, and any network architecture capable of realizing the functions of the above-mentioned network elements is applicable to the embodiments of the present application.

[0104] It should also be understood that Figure 1 The AMF, SMF, UPF, network slice selection function (NSSF), PCF, and UDM shown in FIG. 1 can be understood as network elements in the core network for realizing different functions, for example, can be combined into a network slice as needed. These core network network elements can be independent devices or can be integrated into the same device to realize different functions, and the present application does not limit the specific form of the above-mentioned network elements.

[0105] It should also be understood that the above-mentioned naming is only defined for the convenience of distinguishing different functions and should not constitute any limitation on the present application. The present application does not exclude the possibility of using other names in 5G networks and future other networks. For example, in a 6G network, part or all of the above-mentioned network elements can use the terms in 5G, or other names, etc. Figure 1 The interface names between the network elements in the above-mentioned network architecture are only an example, and the names of the interfaces in the specific implementation can be other names, and the present application does not make specific limitations thereon. In addition, the names of the messages (or signaling) transmitted between the above-mentioned network elements are also only an example, and do not constitute any limitation on the functions of the messages themselves.

[0106] In order to facilitate the understanding of the embodiments of the present application, first, the terms involved in the present application are briefly explained.

[0107] 1. Session: A session enables data transmission between a terminal device and a DN. In embodiments of the present application, a session can be, for example, a protocol data unit (PDU) session. A 5G core network (5G core, 5GC) supports PDU connection services. A PDU connection service can refer to a service in which PDU data packets are exchanged between a terminal device and a DN. A PDU connection service is implemented by the terminal device initiating establishment of a PDU session. After a PDU session is established, a data transmission channel between the terminal device and the DN is established. Each terminal device can establish one or more PDU sessions. A PDU session can be identified by a PDU session identifier (PDU session ID). In other words, one possible form of identification information of a session is a PDU session identifier.

[0108] It should be understood that a PDU session is one possible form of a session, and should not constitute any limitation on the present application.

[0109] 2. Network slicing (NS): Network slicing is an end-to-end logical dedicated network that provides specific network capabilities. By flexibly allocating network resources and networking on demand, multiple logical subnets with different characteristics and mutual isolation can be virtually created on the same physical infrastructure to provide services to users. The logical subnet is referred to as a network slice. Network slicing can be used by an operator to provide mutually isolated and functionally customizable network services for different vertical industries, different customers, and different services based on service level agreements (SLAs) signed with customers. Different network slices can be identified and distinguished by single network slice selection assistance information (S-NSSAI).

[0110] There are often many access network devices, such as gNBs, in the entire service area of a network slice. Each access network device has a certain coverage area, which can be one or more cells. Each cell has a unique global cell identifier (CGI). The entire service area of the network slice is divided into several areas, i.e., one or more tracking areas (TAs). A TA can be identified by a tracking area identifier (TAI). A TA is composed of one or more cells.

[0111] 3、cell: A cell is described from the perspective of resource management, mobility management or service unit by a higher layer. The coverage of each access network device can be divided into one or more cells, and each cell can correspond to a frequency range. Each cell can work in the corresponding frequency range. The frequency range can be a frequency point or a frequency band. This application does not limit this.

[0112] It should be noted that the cell can be an area within the coverage of the wireless network of the access network device. In the embodiments of the present application, different cells can correspond to the same or different access network devices.

[0113] For example, the access network device serving cell #1 and the access network device serving cell #2 can be different access network devices, such as base stations. That is, cell #1 and cell #2 can be managed by different base stations.

[0114] For example, the access network device serving cell #1 and the access network device serving cell #2 can be the same access network device, such as a base station. That is, cell #1 and cell #2 can be managed by the same base station, in which case cell #1 and cell #2 can be referred to as co-sited.

[0115] One possible case where cell #1 and cell #2 are co-sited is that the access network device serving cell #1 and the access network device serving cell #2 are different radio frequency processing units of the same base station, such as radio remote units (RRUs), that is, cell #1 and cell #2 can be managed by the same base station, have the same baseband processing unit and intermediate frequency processing unit, but have different radio frequency processing units.

[0116] The source cell is the cell in which the terminal device resides before handover, or the cell in which the terminal device resides before cell reselection. The source cell in the embodiments of the present application is a cell served by the first access network device. The target cell is a cell that the first access network device determines for the terminal device to switch to. The target cell in the embodiments of the present application can be a cell served by the first access network device, or a cell served by the second access network device.

[0117] The cell served by each access network device can be one or more. The cells served by the same access network device can work in different frequency ranges, or can work in the same frequency range.

[0118] It should be understood that the wireless resources supported by each cell are not limited to frequency ranges, but can also include time domain resources, spatial domain resources, etc., which are not listed here.

[0119] 4、Handover: In a wireless communication system, when a terminal device moves / closes to another cell from a cell, in order to keep the communication of the terminal device uninterrupted, handover is needed. In the embodiments of the present application, the source cell represents the cell that provides services for the terminal device before handover, and the target cell represents the cell that provides services for the terminal device after handover.

[0120] The handover can be an intra-station handover or an inter-station handover. The intra-station handover can refer to that the source cell and the target cell belong to the same access network device (such as gNB); the inter-station handover can refer to that the source cell and the target cell belong to different access network devices (such as gNB). The present application does not limit this.

[0121] 5、RRC connection: Before normal communication, the terminal device can establish an RRC connection between the terminal device and the network device, or in other words, an RRC connection between the terminal device and the cell. When the RRC connection is disconnected, the terminal device can enter an RRC idle state (also referred to as idle state) and cannot normally communicate.

[0122] When the terminal device is in the RRC connected state, the terminal device can transmit data through the currently activated session, and can also request to establish a session or request to activate a session. When the terminal device is in the RRC idle state, the terminal device cannot establish or activate a session, and the session activated in the RRC connected state is also deactivated.

[0123] 6、Intra-station neighboring cell: A neighboring cell served by the same access network device. For example, cell #1 and cell #2 in the following are intra-station neighboring cells.

[0124] 7、Inter-station neighboring cell: A neighboring cell served by different access network devices. For example, cell #1 and cell #4 in the following are inter-station neighboring cells.

[0125] In order to better understand the embodiments of the present application, the following points are first explained:

[0126] First, the following assumptions and definitions are made for the convenience of understanding and description:

[0127] Cell #1: The cell in which the terminal device resides before handover, or the cell in which the terminal device resides before cell reselection. That is, the above-mentioned source cell.

[0128] It should be understood that the source cell and the target cell are both relative to a certain terminal device. For example, cell #1 is the source cell of the terminal device in the embodiments of the present application, but it can also be the target cell of other terminal devices.

[0129] Cell #2: A cell co-sited with Cell #1, and Cell #2 is a neighboring cell of Cell #1. Since Cell #1 and Cell #2 are co-sited, Cell #2 can be referred to as an intra-site neighboring cell of Cell #1. It should be understood that the intra-site neighboring cells of Cell #1 can include, but are not limited to, Cell #2, for example, also including Cell #3.

[0130] Cell #3: Another intra-site neighboring cell of Cell #1.

[0131] Cell #4: A cell not co-sited with Cell #1, and Cell #4 is a neighboring cell of Cell #1. Since Cell #1 and Cell #4 are not co-sited, Cell #4 can be referred to as an inter-site neighboring cell of Cell #1. It should be understood that the inter-site neighboring cells of Cell #1 can include, but are not limited to, Cell #4.

[0132] First access network device: An access network device serving Cell #1. The cells served by the first access network device can include only Cell #1, or can include Cell #2, or can include other cells in addition to Cell #1 and Cell #2, such as Cell #3.

[0133] Second access network device: An access network device different from the first access network device. The cells served by the second access network device can include only Cell #4, or can include other cells in addition to Cell #4.

[0134] It should be understood that the cells served by the second access network device are adjacent to the cells served by the first access network device, for example, one or more of the cells served by the second access network device are neighboring cells of Cell #1. Therefore, the second access network device can be referred to as an access network device having a neighboring cell relationship with the first access network device. However, it should be understood that the access network device having a neighboring cell relationship with the first access network device is not necessarily limited to the second access network device, and in this application, the second access network device is taken as an example for the sake of understanding and description. However, this should not constitute any limitation on this application.

[0135] S-NSSAI #1: An identifier of a network slice corresponding to session 1.

[0136] S-NSSAI #2: An identifier of a network slice corresponding to session 2.

[0137] S-NSSAI #3: An identifier of a network slice corresponding to session 3.

[0138] Target frequency range: A frequency range supported by a target cell. The first access network device preferentially selects a first frequency range supported by a source cell (such as Cell #1) as the target frequency range.

[0139] The first frequency range is a frequency range supported by the source cell, i.e., a frequency range corresponding to the first wireless resource of the source cell. For example, in the embodiments of the present application, the first frequency range is the N41 frequency band.

[0140] It should be understood that, for the convenience of distinguishing and description, different access network devices, different cells, different network slices and different sessions are distinguished by different numbers in the present application. These numbers are only examples and should not constitute any limitation on the present application. Moreover, the present application does not limit the specific form of identification of gNB, cell, network slice and session.

[0141] Secondly, in the present application, the description related to the sending of messages or data by network element A to network element B and the receiving of messages or data by network element B from network element A is intended to illustrate which network element the messages or data are intended for, and does not limit whether they are directly sent or indirectly sent via other network elements.

[0142] For example, the sending of messages or data packets by the first access network device to the second access network device does not limit the sending of messages or data packets by the first access network device to the second access network device directly. In the Ng handover scenario, since the Xn interface communication is not supported between the first access network device and the second access network device, the communication between the first access network device and the second access network device can be forwarded through the AMF. In the Xn handover scenario, since the Xn interface communication is supported between the first access network device and the second access network device, the first access network device and the second access network device can directly interact without the forwarding of the AMF. Although not listed one by one, those skilled in the art can understand the meaning thereof.

[0143] Thirdly, in the multiple flowcharts shown below, the Xn interface handover is taken as an example to describe the embodiments. If there is no Xn interface between the first access network device and the second access network device, the Ng interface handover is performed.

[0144] In addition, in the case where there is no Xn interface, the OAM can send configuration information to each access network device to indicate the network slices supported by the cells served by each access network device and the frequency ranges corresponding to each network slice, and the first access network device and the second access network device can no longer exchange the network slices supported by each other and the frequency ranges corresponding to each network slice through the Xn interface.

[0145] In addition, in the case where there is no Xn interface, the interaction between the first access network device and the second access network device can be forwarded through the AMF. The other processes are basically similar, and for the sake of brevity, the embodiments are not described below.

[0146] Fourth, in the embodiments of the present application, "when", "in the case of", "if" and the like all refer to the device (such as a terminal device or a network device) making corresponding processing under certain objective circumstances, and are not limited to time, and do not require the device (such as a terminal device or a network device) to have a judgment action when implemented, nor does it mean that there are other limitations.

[0147] Fifth, in the embodiments shown below, the first, second, and various numbers are only for differentiation for the convenience of description, and are not used to limit the scope of the embodiments of the present application. For example, different multicast data, different UEs, different PDU sessions, and the like are distinguished.

[0148] Sixth, "at least one" means one or more, and "multiple" means two or more. The association relationship of the associated objects is described, which means that there can be three relationships, for example, A and / or B, which can mean: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, and c can mean: a, or b, or c, or a and b, or a and c, or b and c, or a, b, and c. Where a, b, and c can be single or multiple.

[0149] Seventh, in the following multiple embodiments, multiple existing signaling is listed. It should be understood that the names of these signals are only examples for the convenience of understanding, and should not constitute any limitation on the present application. The present application does not exclude the possibility of defining other signaling names in future protocols to replace the signaling names listed in the present application to achieve the same or similar functions. For example, "RRC connection release message" can also be "RRC release message" and the like. For the sake of brevity, they are not listed one by one.

[0150] The communication method provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0151] Figure 2 is a schematic flowchart of the communication method 200 provided by an embodiment of the present application. As Figure 2 shown, the method 200 can include steps 210 to 230. The steps in the method 200 will be described in detail below.

[0152] In step 210, the first access network device determines that the terminal device satisfies a cell switching condition.

[0153] In step 220, the first access network device determines a target cell.

[0154] In step 230, the first access network device controls the terminal device to switch to a target cell.

[0155] The first access network device can actively find a target cell for the terminal device in the case that the terminal device meets the cell switching condition, and control the terminal device to switch to the target cell. Instead of initiating cell reselection after the terminal device enters the idle state, the terminal device does not have to wait until the current service of the terminal device is completed before switching the cell. Therefore, the terminal device can be switched to a suitable cell in time, so that the communication quality of the terminal device can be improved in a short time, which is beneficial to improving the user experience.

[0156] Optionally, the first access network device determines in step 210 that the terminal device meets the cell switching condition, specifically including: the first access network device determines that the signal quality of the terminal device in the source cell is lower than a preset threshold.

[0157] The signal quality can be evaluated by reference signal receiving power (RSRP) or reference signal receiving quality (RSRQ), for example. Illustratively, the RSRP or RSRQ of the reference signal (RS) received by the terminal device in a certain cell can be used for evaluation. It should be understood that RSRP, RSRQ, etc. can be understood as an index for evaluating the signal quality.

[0158] The preset threshold can be understood as a threshold value for judging whether the signal quality is good or poor. Different evaluation indexes correspond to different threshold values. In addition, the preset threshold can be a predefined threshold value. The present application does not limit the specific value thereof. In order to distinguish from the threshold value in the following, the threshold for judging the signal quality of the terminal device in the source cell is referred to as the first preset threshold.

[0159] One possible scenario is that the terminal device and the first access network device can be in an RRC connected state. The terminal device can have established and activated one or more sessions in the source cell. The terminal device can perform data transmission through the activated one or more sessions.

[0160] If the first access network device determines that the signal quality of the terminal device in the source cell is lower than the first preset threshold, it can be determined that the terminal device meets the cell switching condition. The first access network device can perform step 220 to determine a target cell, and step 230 to control the terminal device to switch to the target cell.

[0161] The embodiments described below show the specific flow of the communication method in this scenario. Figure 3 The embodiments described below show the specific flow of the communication method in this scenario.

[0162] Optionally, the first access network device determines in step 210 that the terminal device meets the cell switching condition, specifically including: the first access network device determines that the first wireless resource of the source cell does not support a first network slice corresponding to a first session requested by the terminal device to establish or activate in the source cell.

[0163] The wireless resource can include, but is not limited to, frequency domain resource, time domain resource, space domain resource, code domain resource, etc. The frequency domain resource can specifically refer to the frequency range supported by the cell. Alternatively, the cell can work in the supported frequency range.

[0164] In the embodiments of the present application, for the convenience of distinguishing and explaining, the wireless resource supported by the source cell is recorded as the first wireless resource, the session requested by the terminal device to establish or activate in the source cell is recorded as the first session, and the network slice corresponding to the first session is recorded as the first network slice. The first wireless resource does not support the first network slice corresponding to the first session requested by the terminal device to establish or activate, which can specifically refer to that the frequency range corresponding to the first wireless resource does not support the first network slice, or in other words, the source cell does not support the first network slice. Therefore, the frequency range provided by the source cell cannot provide access services for the first network slice corresponding to the first session requested by the terminal device to establish or activate. Since in the usual case, each cell can work in the corresponding frequency range, or in other words, each cell can provide access services of the supported network slice in the corresponding frequency range, therefore, the frequency range corresponding to the first wireless resource of the source cell does not support the first network slice, that is, the source cell does not support the first network slice.

[0165] A possible scenario is that the terminal device accesses the network after starting up, or initiates a registration request to the network because it moves to a new TA that does not belong to the original registration area. Alternatively, the terminal device initiates a registration request to the network when it periodically updates the registration to the network. The terminal device can carry a session list requested to establish or activate in the registration request. The session list includes the identification information of the session requested by the terminal device to establish and / or activate. The session requested by the terminal device to establish or activate can include, but is not limited to, the first session. The embodiments described below show the specific process of the communication method in this scenario. Figure 4

[0166] Another possible scenario is that when the terminal device is transferred from the RRC idle state to the RRC connected state, it expects to activate the user plane connection of the session deactivated in the RRC idle state. The terminal device can carry a session list requested to activate when it initiates an RRC connection request to the first access network device. The session list can include the identification information of the session requested by the terminal device to activate. The session requested to activate can include, but is not limited to, the first session. The embodiments described below show the specific process of the communication method in this scenario.​Figure 5 The described embodiments show the specific procedure of the communication method in this scenario.

[0167] Another possible scenario is that the terminal device intends to establish a new session. The terminal device can send a session establishment request message to the first access network device to request establishment of one or more sessions. The one or more sessions requested by the terminal device to be established may, for example, include but are not limited to the first session. In the following, the description is combined with Figure 6 and Figure 7 The described embodiments show the specific procedure of the communication method in this scenario.

[0168] In any of the above possible scenarios, if the first access network device determines that the first wireless resource does not support the first network slice corresponding to the first session requested by the terminal device to be established or activated, it can be determined that the terminal device meets the cell switching condition. The first access network device can perform step 220 to determine a target cell, and step 230 to control the terminal device to switch to the target cell.

[0169] The target cell determined by the first access network device for the terminal device can be an intra-station neighboring cell of the source cell, or an inter-station neighboring cell of the source cell, which is not limited in the present application.

[0170] In one possible implementation, the first access network device can preferentially search for a target cell in the intra-station neighboring cells. If a target cell can be found in the intra-station neighboring cells, the terminal device can perform an intra-station cell switching without the need to switch the access network device. If the first access network device cannot find a suitable cell as the target cell in the intra-station neighboring cells, it can search for the target cell in the inter-station neighboring cells. If the first access network device finds a target cell in the inter-station neighboring cells, the terminal device can perform an inter-station cell switching, and the terminal device needs to switch the access network device at this time. It is assumed here that the terminal device switches to a second access network device, which is the access network device serving the target cell.

[0171] In another possible implementation, the first access network device determines that the cell it serves only includes the cell #1, and directly searches for a target cell from the inter-station neighboring cells. If the first access network device finds a target cell in the inter-station neighboring cells, the terminal device can perform an inter-station cell switching, and the terminal device needs to switch to the second access network device at this time.

[0172] Since the description of the communication method provided by the present application applied to the specific process of the above scenario will be described below Figures 3 to 7 The specific process of the communication method provided by the present application applied to the above scenario will not be described in detail here for brevity.

[0173] Figure 3 is another exemplary flowchart of the communication method provided by the embodiments of the present application.Figure 3 The method 300 shown can include steps 301 to 307.

[0174] To facilitate understanding of this embodiment, first, the scenario to which the method 300 is applicable is described as follows: the terminal device is in an RRC connected state with the first access network device. The terminal device is in a cell #1 served by the first access network device, and there is an active session 1 in the terminal device in the cell #1, and the network slice corresponding to the session 1 is a network slice identified as S-NSSAI #1. The cells served by the first access network device can also include a cell #2, which is a neighboring cell of the cell #1. It should be understood that the session 1 is an example of a first session, and the network slice identified as S-NSSAI #1 is an example of a first network slice.

[0175] In the method 300, step 303 can correspond to step 210 in the method 200, and illustrates one possible implementation of step 210 in which the first access network device determines that the terminal device satisfies the cell switching condition.

[0176] Step 304 can correspond to step 220 in the method 200, and illustrates a possible implementation of step 220 in which the first access network device determines the target cell. In step 304, one possible case is that the target cell is a cell other than the source cell among the multiple cells served by the first access network device. That is, the first access network device can determine the target cell from the intra-station neighboring cells. Another possible case is that the target cell is a cell served by the second access network device. That is, the first access network device can determine the target cell from the inter-station neighboring cells. In the case of determining the target cell from the inter-station neighboring cells, the method can further include: determining, by the first access network device, a radio measurement parameter according to the first network slice, the network slices supported by the at least one neighboring cell respectively, and the radio resources corresponding to the supported network slices; and sending, by the first access network device, the radio measurement parameter to the terminal device, the radio measurement parameter being used for measurement of signal quality of the neighboring cells by the terminal device, and the measurement of signal quality of the neighboring cells by the terminal device being used for determination of the target cell.

[0177] Step 305 can correspond to step 230 in method 200, and shows a possible implementation of step 230 in which the first access network device controls the terminal device to perform handover to the target cell. Corresponding to step 304, one possible implementation of step 305 is that the first access network device controls the terminal device to perform an intra-site handover. Another possible implementation of step 305 is that the first access network device controls the terminal device to perform a cross-site handover. In the case of cross-site handover, the method can further include: step 3051, the first access network device sends a request message to the second access network device, the request message carrying the identification information of the first session and the identification information of the first network slice; step 3052, the second access network device determines the RRC parameters according to the information of the session to be handed in; step 3053, the first access network device receives the RRC parameters for handover from the second access network device; step 3054, the first access network device sends the RRC parameters to the terminal device; and step 3055, the terminal device accesses the radio resources of the second access network device according to the RRC parameters. Optionally, the RRC parameters are associated with the first network slice, the network slices supported by the second access network device, and the radio resources corresponding to the network slices supported by the second access network device.

[0178] The method 300 will be described in detail below in combination with a specific flow.

[0179] In step 301, the first access network device receives first configuration information from an OAM, the first configuration information being used to indicate the network slices supported by the first access network device and the radio resources corresponding to the network slices.

[0180] For example, during network slice planning and deployment, an OAM entity (hereinafter referred to as OAM) can send configuration information to each access network device. The configuration information sent by the OAM to each access network device can be used to indicate the network slices supported by each access network device respectively and the radio resources corresponding to the supported network slices. The configuration information sent by the OAM to the first access network device can be referred to as first configuration information. Since the radio resources include frequency domain resources, the radio resources corresponding to the network slices include the frequency ranges corresponding to the network slices.

[0181] It should be understood that the first access network device can configure the network slices and the frequency ranges supported by each cell based on the first configuration information. Thus, the network slices supported by each cell and the frequency ranges corresponding to each network slice can be determined. It should also be understood that when the first access network device serves multiple cells, the network slices supported by each cell and the frequency ranges corresponding to each network slice are not necessarily the same. As mentioned earlier, each cell can correspond to a frequency range. Or, each cell works in the frequency range it supports.

[0182] In an example, the first configuration information can comprise: {S-NSSAI#1, (N41)} and {S-NSSAI#2, (N41)}, indicating that the first access network device supports to provide access services of network slices identified as S-NSSAI#1 and S-NSSAI#2 in the N41 frequency band.

[0183] It is assumed that the cells served by the first access network device comprise cell#1 and cell#2. The first access network device can configure supported network slices and frequency ranges for each cell as follows: the network slices supported by cell#1 can comprise, for example, a network slice identified as S-NSSAI#1, and the frequency range corresponding to the network slice is the N41 frequency band. The network slices supported by cell#2 can comprise, for example, network slices identified as S-NSSAI#1 and S-NSSAI#2, and the frequency range corresponding to the two network slices is the N41 frequency band.

[0184] In another example, the first configuration information can comprise: {S-NSSAI#1, (N41)} and {S-NSSAI#2, (N41, N79)}, indicating that the first access network device supports to provide access services of network slices identified as S-NSSAI#1 and S-NSSAI#2 in the N41 frequency band, and supports to provide access services of the network slice identified as S-NSSAI#2 in the N79 frequency band.

[0185] It is assumed that the cells served by the first access network device comprise cell#1 and cell#2. The first access network device can configure supported network slices and frequency ranges for each cell as follows: the network slices supported by cell#1 can comprise, for example, network slices identified as S-NSSAI#1 and S-NSSAI#2, and the frequency range corresponding to the two network slices is the N41 frequency band. The network slices supported by cell#2 can comprise, for example, a network slice identified as S-NSSAI#2, and the frequency range corresponding to the network slice is the N79 frequency band.

[0186] In another example, the first configuration information can comprise: {S-NSSAI#1, (N41)} and {S-NSSAI#2, (N41, N79)}, indicating that the first access network device supports to provide access services of network slices identified as S-NSSAI#1 and S-NSSAI#2 in the N41 frequency band, and supports to provide access services of the network slice identified as S-NSSAI#2 in the N79 frequency band.

[0187] It is assumed that the cells served by the first access network device include cell #1, cell #2 and cell #3. The first access network device can configure the supported network slices and the frequency ranges for the cells as follows: the network slices supported by cell #1 may, for example, include a network slice identified as S-NSSAI#1, and the frequency range corresponding to the network slice is the N41 frequency band. The network slices supported by cell #2 may, for example, include network slices identified as S-NSSAI#1 and S-NSSAI#2, and the frequency range corresponding to the two network slices is the N41 frequency band. The network slices supported by cell #3 may, for example, include a network slice identified as S-NSSAI#1, and the frequency range supported by cell #3 is the N79 frequency band.

[0188] It should be understood that the frequency ranges corresponding to the network slices in different cells are not necessarily the same, which is related to the frequency ranges supported by the cells.

[0189] It should also be understood that the network slices supported by the cells listed above, the frequency ranges corresponding to the network slices, and the frequency ranges supported by the cells are only examples and should not constitute any limitation on the present application. The present application does not limit the network slices supported by the cells, the frequency ranges corresponding to the network slices, and the frequency ranges supported by the cells.

[0190] It should be noted that when an operator performs network planning, in order to ensure as much as possible that the handover of a terminal device is an intra-frequency handover, multiple cells operating in the same frequency range can often support the same network slice. For example, cell #1 and cell #2 both support operating in the N41 frequency band, and cell #1 and cell #2 both support a network slice identified as S-NSSAI#1.

[0191] For convenience of understanding and description, it is assumed below that the first configuration information can include: {S-NSSAI#1, (N41, N79)} and {S-NSSAI#2, (N41)}. The cells served by the first access network device include cell #1, cell #2 and cell #3. The first access network device can configure the supported network slices and the frequency ranges for the cells as follows: the network slices supported by cell #1 may, for example, include a network slice identified as S-NSSAI#1, and the frequency range corresponding to the network slice is the N41 frequency band. The network slices supported by cell #2 may, for example, include network slices identified as S-NSSAI#1 and S-NSSAI#2, and the frequency range corresponding to the two network slices is the N41 frequency band. The network slices supported by cell #3 may, for example, include a network slice identified as S-NSSAI#1, and the frequency range supported by cell #3 is the N79 frequency band.

[0192] In step 302, the first access network device acquires second configuration information of the second access network device, the second configuration information being used to indicate network slices supported by the second access network device and wireless resources corresponding to each network slice.

[0193] In an implementation, the first access network device can receive the second configuration information from the second access network device. For example, the first access network device can acquire the second configuration information through an Xn interface. For example, if the first access network device and the second access network device can communicate through the Xn interface, the first access network device can acquire the second configuration information through the Xn interface. Alternatively, the second access network device can also receive the second configuration information from the OAM through the method described in step 301 above.

[0194] For an example, the second configuration information sent by the OAM to the second access network device can include: {S-NSSAI#1, (N41, N79)}, {S-NSSAI#2, (N79)}, and {S-NSSAI#3, (N79)}, indicating that the second access network device supports providing access services of the network slice identified as S-NSSAI#1 in the N41 frequency band, and supports providing access services of the network slices identified as S-NSSAI#1, S-NSSAI#2, and S-NSSAI#3 in the N79 frequency band.

[0195] Figure 3 Step 302 in the above method shows that the second access network device receives the second configuration information from the OAM, and the implementation that the first access network device receives the second configuration information from the second access network device.

[0196] It should be understood that the second configuration information received by the first access network device from the second access network device can be the same as the second configuration information received by the second access network device from the OAM, or can be different, for example, can be sent to the first access network device after processing by the second access network device.

[0197] In another implementation, the first access network device can receive the second configuration information from the OAM. For example, the OAM can send the first configuration information and the second configuration information to the first access network device through the same signaling. Of course, the OAM can also send configuration information of other access network devices to the first access network device through the same signaling, where the other access network devices can refer to access network devices having a neighboring cell relationship with the first access network device.

[0198] It should be noted that step 302 is an optional step. When the target cell determined by the first access network device in the subsequent steps is an intra-station neighboring cell, the first access network device actually does not use the information acquired through step 302.

[0199] In step 303, the first access network device determines that the signal quality of the terminal device in the cell #1 is lower than a first preset threshold.

[0200] The terminal device has established a first session in the cell #1, and a user plane connection of the first session is activated. An identity of a first network slice corresponding to the first session is S-NSSAI #1. The context of the terminal device saved by the first access network device includes information of the first session.

[0201] It should be understood that the session established and activated by the terminal device in the cell #1 is not necessarily limited to the first session, and multiple sessions can also be established and activated. For the convenience of understanding and description, the first session is taken as an example to illustrate the method provided by the present application.

[0202] The first access network device can determine whether the signal quality of the terminal device in the cell #1 is lower than the first preset threshold according to the measurement of the terminal device on the signal quality of the cell #1. If the signal quality of the terminal device in the cell #1 is lower than the first preset threshold, that is, the signal quality of the terminal device in the cell #1 is not good. The first access network device can determine that the terminal device is not suitable to continue camping in the cell #1, and the terminal device meets the cell switching condition.

[0203] In an implementation manner, the terminal device can measure the signal quality of the source cell and report the measurement result (such as the above-mentioned RSRP, RSRQ and the like) to the first access network device. The first access network device can determine whether the signal quality meets the first preset threshold according to the measurement result. The first access network device can further determine that the terminal device meets the cell switching condition in the case that the signal quality is lower than the first preset threshold.

[0204] In another implementation manner, the terminal device can report an event that the signal quality is lower than the first preset threshold to the first access network device according to the measurement of the signal quality of the source cell in the case that the signal quality is lower than the first preset threshold. The first access network device determines that the terminal device meets the cell switching condition according to the event.

[0205] It should be understood that the measurement of the terminal device on the signal quality of the cell #1 can refer to the prior art, and for the sake of brevity, it is not described in detail here.

[0206] In step 304, the first access network device determines a target cell according to the first network slice corresponding to the first session and the network slices supported by at least one neighboring cell respectively.

[0207] To maintain normal communication of the first session, the first access network device can consider the first network slice corresponding to the first session when determining the target cell for the terminal device. That is, the target cell determined by the first access network device for the terminal device supports the first network slice to avoid interruption of the first session.

[0208] The first access network device can select a cell supporting the first network slice from the at least one neighboring cell as the target cell according to the first network slice and the network slices supported by the at least one neighboring cell obtained in advance.

[0209] The first access network device can preferentially search for the target cell in the intra-station neighboring cells. If the first access network device finds the target cell in the intra-station neighboring cells, the target cell is a cell other than the source cell in the plurality of cells served by the first access network device.

[0210] For example, the intra-station neighboring cells of the cell #1 include the cell #2, and the cell #2 also supports the first network slice, the first access network device can determine whether the cell #2 can be used as the target cell according to the signal quality of the cell #2. If the signal quality of the cell #2 meets a preset threshold (for the convenience of distinguishing and describing, the preset threshold is referred to as a second preset threshold), the cell #2 can be used as the target cell.

[0211] For example, the identity of the first network slice is S-NSSAI #1, and the network slices supported by the cell #2 include the network slices with identities of S-NSSAI #1 and S-NSSAI #2, the cell #2 also supports the first network slice. The first access network device can further determine whether the cell #2 can be used as the target cell according to the signal quality of the cell #2.

[0212] For another example, the first access network device can search for the neighboring cell of the cell #1 from the cells with signal quality meeting the second preset threshold according to the signal quality of the intra-station cells. If the neighboring cell of the cell #1 can be found from the cells with signal quality meeting the second preset threshold, the cell can be determined as the target cell.

[0213] For example, the identity of the first network slice is S-NSSAI #1. The first access network device determines that there are cells meeting the second preset threshold in the intra-station cells, including the cell #2. As described above, the cell #2 also supports the network slice with the identity of S-NSSAI #1, and thus the cell #2 can be used as the target cell.

[0214] For another example, the intra-station neighboring cells of the cell #1 include a plurality of cells supporting the first network slice, and the plurality of cells supporting the first network slice support different frequency ranges, the first access network device can preferentially search for the target cell in the cells with the same frequency as the cell #1.

[0215] Here, the same frequency can specifically refer to that the frequency ranges supported by the two cells are the same, for example, working in the same frequency range; in contrast, the different frequency can specifically refer to that the frequency ranges supported by the two cells are different, for example, working in different frequency ranges.

[0216] For an example, the identity of the first network slice is S-NSSAI#1, and the frequency range supported by the cell #1 is N41 band. The in-station neighboring cells of the cell #1 include the cell #2 and the cell #3. It is assumed that the network slices supported by the cell #2 include the network slices with the identities of S-NSSAI#1 and S-NSSAI#2, and the frequency range supported by the cell #2 is N41 band; the network slices supported by the cell #3 include the network slice with the identity of S-NSSAI#1, and the frequency range supported by the cell #3 is N79 band. Then, the first access network device can preferentially consider whether the signal quality of the cell #2 reaches the second preset threshold. If the signal quality of the cell #2 satisfies the second preset threshold, the cell #2 can be taken as the target cell.

[0217] It should be noted that the first access network device can obtain the measurement results of the signal qualities of the cells from other terminal devices in multiple cells served by the first access network device, and thus, the first access network device can determine whether the in-station neighboring cell supporting the first network slice satisfies the second preset threshold according to the measurement results of the signal qualities of the in-station neighboring cells.

[0218] It should be understood that the second preset threshold can be understood as another threshold value used to determine whether the signal quality is good or poor. Different evaluation indexes correspond to different threshold values. In addition, the second preset threshold can be a predefined threshold value. The specific value of the second preset threshold is not limited in the present application.

[0219] It should also be understood that the first preset threshold and the second preset threshold are different preset thresholds. Different indexes can be used, or the same index and different threshold values can be used, or the same index and the same threshold value can be used. The present application does not limit this.

[0220] The first access network device can also find the target cell from the out-station neighboring cells. If the first access network device finds the target cell from the out-station neighboring cells, the target cell can be, for example, a cell served by a second access network device.

[0221] The first access network device finds the target cell from the out-station neighboring cells, which is also based on the cell supporting the first network slice. The specific implementation process is similar to the process of finding the target cell in the in-station neighboring cells described above. For brevity, the details are not described herein.

[0222] In the embodiment of the present application, one possible implementation of step 304 is that the first access network device can determine the target frequency range according to the first network slice, and the network slices supported by the at least one out-of-coverage neighboring cell and the wireless resources corresponding to each network slice, and then find the target cell based on the target frequency range.

[0223] For example, step 304 can specifically include:

[0224] Step 3041: The first access network device determines the target frequency range according to the first network slice, the network slices supported by the at least one neighboring cell, and the frequency ranges corresponding to each network slice.

[0225] Step 3042: The first access network device determines the target cell according to the target frequency range.

[0226] In step 3041, the target frequency range is a frequency range that the target cell determined by the first access network device for the terminal device can support.

[0227] The first access network device can find a cell supporting the first network slice from the at least one neighboring cell according to the first network slice, and determine the target frequency range according to the frequency range corresponding to each cell of the first network slice.

[0228] Since the frequency ranges supported by each cell are different, although there can be multiple cells supporting the first network slice, the frequency ranges corresponding to each cell are not necessarily the same. Therefore, the target frequency range can be the same as the frequency range supported by cell #1, or can be different from the frequency range supported by cell #1, which is not limited in the present application. For convenience of distinguishing and description, the frequency range supported by cell #1 is recorded as the first frequency range.

[0229] In one implementation, the first access network device can preferentially select the same frequency range as cell #1 as the target frequency range. In the case that there is a cell supporting the first network slice in the neighboring cells and the corresponding frequency range is the first frequency range, the first frequency range is preferentially selected as the target frequency range; otherwise, the other frequency range corresponding to the first network slice supported by the neighboring cell is selected as the target frequency range. For the convenience of distinguishing and description, the frequency range corresponding to the first network slice supported by the neighboring cell and different from the first frequency range is recorded as the second frequency range. In other words, the target frequency range is preferentially the first frequency range, and secondarily the second frequency range.

[0230] As shown in the above example, the first frequency range is N41 band. Among the neighboring cells of the cell #1, the cell supporting the network slice identified as S-NSSAI#1, the frequency range corresponding to the network slice includes N41 and N79 bands. Then, the target frequency range preferentially selects N41 band. It can be understood that if the neighboring cells of the cell #1 do not support N41 band, the target frequency range can be N79 band. N79 band is an example of the second frequency range.

[0231] Optionally, the step 3042 specifically includes that the first access network device determines the target cell from the intra-station neighboring cells supporting the target frequency range.

[0232] Exemplarily, if the first access network device determines that the target frequency range is the first frequency range, the first access network device can first determine whether there is a cell supporting the first frequency range in the intra-station neighboring cells of the cell #1, for example, a first cell. In the case that the first cell exists, the first access network device can determine whether to determine the first cell as the target cell according to the signal quality of the first cell. For example, if the signal quality of the first cell meets a second preset threshold, the first cell is determined as the target cell. If the signal quality of the first cell is lower than the second preset threshold, or the cell #1 does not have intra-station neighboring cells (i.e., the cells served by the first access network device only include the cell #1), the first access network device can determine the target cell in the inter-station neighboring cells.

[0233] Optionally, the step 3042 specifically includes that the first access network device determines the target cell from the inter-station neighboring cells supporting the target frequency range. If the first access network device determines that the target frequency range is the first frequency range, the wireless measurement parameter can be determined based on the first frequency range. For the convenience of distinguishing and description, the wireless measurement parameter determined based on the first frequency range is referred to as the first wireless measurement parameter.

[0234] The first access network device can send the first wireless measurement parameter to the terminal device. The terminal device can measure the signal quality of the neighboring cell based on the first wireless measurement parameter. In other words, the first wireless measurement parameter triggers the terminal device to perform the intra-frequency measurement.

[0235] As described above, in order to ensure the handover of the terminal device is intra-frequency handover as much as possible when the operator performs network planning, the multiple cells working in the same frequency range can all support the same network slice. Therefore, it can be understood that the measurement of the signal quality of the neighboring cell by the terminal device based on the first wireless measurement parameter is the measurement in the first frequency range, that is, the measurement of the signal quality of the neighboring cell supporting the first frequency range and the first network slice.

[0236] Afterwards, the terminal device reports the measurement result to the first access network device. It can be understood that the measurement result reported by the terminal device is a measurement result obtained by measuring the signal quality of the neighboring cells in the first frequency range based on the first radio measurement parameter. Exemplarily, the measurement result can include the cell identifier of one or more neighboring cells and the corresponding signal quality of each neighboring cell.

[0237] It can be understood that the cells reported in the measurement result can basically provide the access service of the first network slice in the first frequency range. The first access network device can determine the target cell according to the measurement result. As described above, the first access network device can determine the cell whose signal quality meets the preset threshold as the target cell. If the first access network device can find the target cell based on the measurement result reported by the terminal device, the first access network device does not have to determine the radio measurement parameter based on other frequency ranges, and the terminal device does not have to perform inter-frequency measurement.

[0238] If the first access network device cannot find the target cell based on the measurement result reported by the terminal device, for example, the signal quality of each neighboring cell is lower than the second preset threshold, the first access network device can take the second frequency range as the target frequency range, and try to find the target cell in the intra-site neighboring cells and the inter-site neighboring cells based on the second frequency range. It can be understood that if the first access network device can find the target cell in the intra-site neighboring cells based on the second frequency range, it does not have to find the target cell in the inter-site neighboring cells.

[0239] The specific process of the first access network device finding the target cell in the intra-site neighboring cells based on the second frequency range is the same as the specific process of the first access network device finding the target cell in the intra-site neighboring cells based on the first frequency range described above, which will not be repeated here for brevity.

[0240] The specific process of the first access network device finding the target cell in the inter-site neighboring cells based on the second frequency range can be achieved by performing the steps of determining the radio measurement parameter, issuing the radio measurement parameter, and determining the target cell according to the measurement result described above.

[0241] The difference is that when determining the radio measurement parameter, the first access network device can take the second frequency range as the target frequency range, and determine the radio measurement parameter based on the second frequency range. For the sake of distinction and description, the radio measurement parameter determined based on the second frequency range is referred to as the second measurement parameter.

[0242] The first access network device can issue the second radio measurement parameter to the terminal device. The terminal device can measure the signal quality of the neighboring cells based on the second radio measurement parameter. In other words, the second radio measurement parameter can trigger the terminal device to perform inter-frequency measurement.

[0243] It can be understood that the measurement of the signal quality of the neighboring cell by the terminal device based on the second radio measurement parameter is a measurement in the second frequency range, i.e., a measurement of the signal quality of the neighboring cell supporting the second frequency range and supporting the first network slice.

[0244] Thereafter, the terminal device can report the measurement result to the first access network device. It can be understood that the measurement result reported by the terminal device this time is a measurement result obtained by measuring the signal quality of the neighboring cell in the second frequency range based on the second radio measurement parameter.

[0245] It can be understood that the reported cells in the measurement result can basically provide access services of the first network slice in the second frequency range. The first access network device can determine the target cell according to the measurement result. As described above, the first access network device can determine the cell whose signal quality meets the preset threshold as the target cell.

[0246] If the first access network device can find the target cell based on the measurement result reported by the terminal device, the first access network device can perform a subsequent step 305 to control the terminal device to switch to the target cell; otherwise, the terminal device can continue to camp in the cell #1.

[0247] It should be understood that the above is shown for the purpose of understanding, and the process of finding the target cell in the intra-site neighboring cell and the inter-site neighboring cell is shown. In actual execution, the first access network device does not necessarily have to perform all the steps listed above. For example, the above step 3042 can only need to be performed once, such as performing the same frequency measurement to find the target cell, and then there is no need to perform the different frequency measurement; or, the neighboring cell does not find the cell of the same frequency range as the cell #1, and the different frequency measurement is directly performed; the step 3042 can need to be performed twice or even more times, such as performing the same frequency measurement and then performing the different frequency measurement; the step of determining the target cell from the inter-site neighboring cell supporting the target frequency range in the step 3042 (for example, including the steps of determining and issuing the radio measurement parameter to the terminal device, receiving the measurement result from the terminal device, and determining the target cell according to the measurement result) can also not need to be performed, such as the first access network device can find the cell of the same frequency range in the intra-site neighboring cell as the target cell. The present application does not limit this.

[0248] It should be noted that the above is a detailed description of the process of determining the target cell by the first access network device with the first session as an example for the convenience of understanding and description. In fact, the sessions activated by the terminal device in the source cell can not necessarily be limited to the first session. The sessions activated by the terminal device in the source cell can also be multiple sessions. In this case, the target cell determined by the first access network device for the terminal device should consider the multiple sessions comprehensively to ensure that the multiple sessions can proceed normally without interruption. Therefore, when determining the target cell, the first access network device should make the network slices corresponding to the multiple sessions activated by the terminal device in the source cell respectively supported by the target cell as much as possible, and all respectively access the wireless resources supported by the target cell. In other words, if there is a cell whose supported network slices include the above multiple sessions, and the multiple network slices can all access the same wireless resources in the cell, the cell is preferred as the target cell.

[0249] In step 305, the first access network device controls the terminal device to switch to the target cell.

[0250] As described above, the target cell can be a cell served by the first access network device, or can not be a cell served by the first access network device. The terminal device can perform an intra-site handover procedure, or can perform a cross-site handover procedure. The intra-site handover procedure and the cross-site handover procedure are described in detail below.

[0251] If the target cell is a cell served by the first access network device, the terminal device can perform an intra-site handover procedure.

[0252] Exemplarily, the first access network device can determine a handover parameter according to the wireless resources supported by the target cell. The handover parameter can include, but is not limited to, the identification of the target cell, the wireless temporary identifier of the terminal device in the target cell, the carrier frequency, the antenna information, the beam information, the dedicated random access channel (RACH) resource, the synchronization signal and physical broadcast channel (PBCH) block associated with the RACH resource, the mapping rule of the quality of service flow (QoS Flow) and the wireless bearer, and the like.

[0253] After that, the first access network device can deliver the handover parameter to the terminal device. In a possible design, the first access network device can deliver the handover parameter to the terminal device through a radio resource management (RRM) configuration message. The handover parameter can be used to allocate a data radio bearer (DRB) for a frequency range of the first session to complete the intra-site handover of the terminal device.

[0254] It should be understood that the specific procedure of the intra-site handover of the terminal device can refer to the prior art, and for the sake of brevity, is not limited here.

[0255] If the target cell is not a cell served by the first access network device, the terminal device can perform a cross-site handover procedure. The terminal device can be handed over from the first access network device to a second access network device. Figure 3 Step 305 in the foregoing embodiment shows the cross-site handover procedure.

[0256] Exemplarily, step 305 can specifically include steps 3051 to 3055.

[0257] In step 3051, the first access network device sends a request message to the second access network device, where the request message carries information of a session to be handed over to the second access network device.

[0258] The first access network device sends a request message to the second access network device, where the request message is used to request to hand over the terminal device to the second access network device. The request message can carry information of a session to be handed over to the second access network device, for example, including but not limited to identification information of the session and identification information of a network slice corresponding to the session. In the foregoing example, the session to be handed over to the second access network device includes the first session, and the network slice corresponding to the first session is the first network slice. Taking the first session as an example, the identification information of the session to be handed over to the second access network device carried in the foregoing request message can include identification of the first session or other information that can be used to identify the first session; and the identification information of the network slice corresponding to the session to be handed over can include identification of the first network slice or other information that can be used to identify the first network slice. The specific form of the identification information of the first session and the first network slice is not limited in the present application.

[0259] In step 3052, the second access network device determines an RRC parameter for handover according to the information of the session to be handed over.

[0260] The second access network device can determine the RRC parameter for handover according to the information of the session to be handed in carried in the request message, in combination with the network slices supported by the second access network device and the radio resources corresponding to each network slice, and the network slice corresponding to the session to be handed in, for example, the first network slice described above.

[0261] The second access network device can also detect whether the network slice corresponding to the session to be handed in is a network slice supported by the second access network device after receiving the request message, and then determine the session allowed to be handed in. For example, if the second access network device does not support the network slice of a certain session, the second access network device can reject to hand in the session.

[0262] For example, the second access network device determines that the first network slice corresponding to the first session, that is, the network slice identified as S-NSSAI#1, is supported by the second access network device, and then prepares to accept the first session to be handed in. According to the network slice identified as S-NSSAI#1 and the operating frequency bands corresponding to the network slice supported by the second access network device including N41 and N79, the second access network device determines that the first session to be handed in can be supported in both the N41 frequency band and the N79 frequency band. Since the frequency range of the first radio resource accessed by the first session in the source cell is the N41 frequency band, the second access network device preferentially allocates data radio bearer (DRB) resources to the first session to be handed in in the N41 frequency band, and determines the corresponding RRC parameter.

[0263] In step 3053, the second access network device sends the RRC parameter to the first access network device.

[0264] In an implementation manner, the RRC parameter can be encapsulated in an RRC message container and sent to the terminal device by the first access network device. That is, the first access network device can transparently transmit the RRC parameter from the second access network device to the terminal device.

[0265] In a possible design, the request message can be a handover request message. The RRC parameter is carried in a handover request acknowledgement (handover request ACK) message.

[0266] In step 3054, the first access network device forwards the RRC parameter to the terminal device.

[0267] In step 3055, the terminal device accesses the radio resource of the second access network device according to the RRC parameter.

[0268] If the terminal device switches the access network device, the method can further include step 306, the second access network device and the terminal device establish a DRB for the successfully switched first session over the air interface, and activate the user plane of the session switched in.

[0269] In step 307, the AMF switches the user plane path of the first session to the second access network device.

[0270] After the terminal device accesses the second access network device, the second access network device can send a message to the AMF to inform the terminal device of switching to the second access network device, and inform the core network to switch the user plane path of the session of the terminal device switched to the second access network device to the second access network device. The core network then performs path switching.

[0271] Thereafter, the session (such as the first session described above) of the terminal device switched in to the second access network device can normally transmit and receive service data.

[0272] It should be understood that the specific process of the terminal device performing inter-site handover can refer to the prior art, and for the sake of brevity, it is not limited here.

[0273] It should also be understood that Figure 3 Steps 305 to 307 are described by taking the terminal device performing inter-site handover as an example. However, this should not constitute any limitation on the present application. In the intra-site handover process, the process related to inter-site handover in step 305 and steps 306 and 307 do not necessarily have to be performed.

[0274] Based on the above technical solution, when the signal quality of the terminal device in the source cell is poor, the first access network device serving the source cell can determine a target cell for the terminal device according to the network slice corresponding to the session activated by the terminal device in the source cell, the network slices supported by at least one neighboring cell, and the frequency range corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can timely switch to a target cell with better signal quality in the case that the signal quality is poor and there is a target cell that can be switched to, so that measures can be taken in time in the case of poor communication quality, without having to enter the idle state for cell reselection after completing the current service. Therefore, the communication quality of the terminal device can be improved in a short time, which is conducive to improving the user experience.

[0275] Figure 4 is another exemplary flowchart of a communication method provided by an embodiment of the present application. Figure 4 The method 400 shown can include steps 401 to 419.

[0276] For the convenience of understanding and description, first, the scenario of the method 400 is described as follows: the terminal device in the method 400 can be a terminal device that accesses the network after starting up, or can also be a terminal device that initiates a registration request after moving to a new tracking area that does not belong to the original registration area, or can also be a terminal device that periodically updates the registration to the network. The cell that the terminal device requests to access is a cell #1 served by the first access network device, and the terminal device requests to establish one or more sessions and / or requests to activate one or more sessions in the cell #1. In the following embodiments, the method provided by the embodiments of the present application is first illustrated by taking the request to establish or request to activate a session 1 as an example, and then taking the request to establish or request to activate multiple sessions including the session 1 as an example. It should be understood that the session 1 is an example of the first session, and the network slice identified as S-NSSAI #1 is an example of the first network slice.

[0277] It should also be understood that the steps performed in the following steps for the request to establish a session are basically similar to the steps performed for the request to activate a session. In the case of difference, the steps for the request to establish a session and the request to activate a session are distinguished respectively in each step.

[0278] In addition, it is assumed in the embodiments that the network slices supported by the first access network device and the frequency ranges corresponding to each network slice include: {S-NSSAI #2, (N41)}, and the frequency range supported by the cell #1 served by the first access network device is the N41 frequency band; the network slices supported by the second access network device and the frequency ranges corresponding to each network slice include: {S-NSSAI #1, (N41, N79)}, {S-NSSAI #2, (N79)}, and {S-NSSAI #3, (N79)}.

[0279] In the method 400, the step 412 can correspond to the step 210 in the method 200, and illustrates one possible implementation manner in which the first access network device determines that the terminal device satisfies the cell switching condition in the step 210.

[0280] Steps 413-414 can correspond to step 220 in method 200, showing possible implementation manners of step 220 in which the first access network device determines the target cell. In step 413, the first access network device can determine a target frequency range according to the network slices allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice. In step 414, the first access network device determines the target cell according to the target frequency range. One possible implementation manner of step 414 is that the first access network device determines the target cell from the in-station neighboring cells supporting the target frequency range. Another possible implementation manner of step 414 is that the target cell is determined from the out-station neighboring cells supporting the target frequency range. In the case of determining the target cell from the out-station neighboring cells supporting the target frequency range, the method can further include: determining, by the first access network device, the radio measurement parameters according to the target frequency range; and sending, by the first access network device, the radio measurement parameters to the terminal device, the radio measurement parameters being used for the terminal device to measure the signal quality of the neighboring cells, and the measurement of the signal quality of the neighboring cells by the terminal device being used for the determination of the target cell.

[0281] Step 415 can correspond to step 230 in method 200. Step 415 shows possible implementation manners of step 230 in which the first access network device controls the terminal device to handover to the target cell. Corresponding to step 414, one possible implementation manner of step 415 is that the first access network device controls the terminal device to perform in-station handover. Another possible implementation manner of step 415 is that the first access network device controls the terminal device to perform cross-station handover. In the case of performing cross-station handover, the method can further include: sending, by the first access network device, a request message to the second access network device, the request message carrying the identification information of the first session and the identification information of the first network slice; receiving, by the first access network device, the RRC parameters for handover from the second access network device; and sending, by the first access network device, the RRC parameters to the terminal device. Optionally, the RRC parameters are associated with the first network slice, the network slices supported by the second access network device, and the radio resources corresponding to the network slices supported by the second access network device.

[0282] The method 400 is described in detail below in combination with a specific flow.

[0283] In step 401, the first access network device obtains configuration information of a plurality of access network devices from an OAM, the configuration information of the plurality of access network devices being used to indicate the network slices supported by the first access network device and the radio resources corresponding to each network slice, and the network slices supported by the access network devices having a neighboring cell relationship and the radio resources corresponding to each network slice.

[0284] For example, the first access network device can receive first configuration information from the OAM, which can be used to indicate the network slices supported by the first access network device and the wireless resources corresponding to each network slice. This process can be implemented, for example, by performing step 301 above.

[0285] The first access network device can also receive other configuration information from the OAM or from other access network devices having a neighboring cell relationship through an Xn interface, such as receiving second configuration information, which can be used to indicate the network slices supported by the second access network device and the wireless resources corresponding to each network slice. This process can be implemented, for example, by performing step 302 above.

[0286] It should be understood that step 401 can be implemented by performing steps 301 and 302 in method 300 above. For brevity, the specific content of step 401 is not repeated here, and the reader can refer to the relevant description of steps 301 and 302 above.

[0287] In step 402, the AMF obtains the configuration information of each access network device.

[0288] After each access network device establishes an N2 interface connection with the AMF, it can report the network slices it supports to the AMF in step 401 above. Alternatively, each access network device can also report the network slices supported by the access network devices of the neighboring cells to the AMF. For example, the first access network device can send the first configuration information to the AMF.

[0289] Since each access network device can also obtain the configuration information of other access network devices from the OAM or through the Xn interface from other access network devices, the AMF can obtain the configuration information of multiple access network devices from a certain access network device. Alternatively, the first access network device can also report the configuration information of other access network devices to the AMF. For example, the first access network device can send the second configuration information to the AMF.

[0290] It should be understood that the specific implementation of the AMF obtaining the configuration information of each access network device is not limited.

[0291] The AMF can determine the network slices that the tracking area or registration area currently occupied by the terminal device can access according to the network slice information supported by each access network device and the network slices supported by the access network devices of the neighboring cells. The network slices that the tracking area or registration area currently occupied by the terminal device can access can specifically refer to the network slices supported by the access network devices in the tracking area or registration area currently occupied by the terminal device.

[0292] For example, the network slices and the corresponding radio resources of the network slices supported by the first access network device indicated by the first configuration information include {S-NSSAI#2, (N41)}; the network slices and the corresponding radio resources of the network slices supported by the second access network device indicated by the second configuration information include {S-NSSAI#1, (N41, N79)}, {S-NSSAI#2, (N79)}, and {S-NSSAI#3, (N79)}. It can be seen that the network slices supported by the first access network device include the network slice identified as S-NSSAI#2, and the network slices supported by the second access network device include the network slices identified as S-NSSAI#1, S-NSSAI#2, and S-NSSAI#3. If the cell served by the first access network device and the cell served by the second access network device are in the same TA, the AMF can determine that the network slices that can be supported by the TA where the terminal device currently locates are the union of the network slices supported by the first access network device and the second access network device, that is, {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3}, instead of only S-NSSAI#2 supported by the first access network device currently accessed by the terminal device.

[0293] In step 403, the terminal device sends, to the AMF via the first access network device, a message for requesting establishment or activation of the first session, where the message carries the identification information of the first session.

[0294] The identification information of the first session may, for example, be an identifier of the first session or other information that can be used to identify the first session. The application does not make any limitation in this regard. In this embodiment, the identification information of the first session may, for example, be Session 1.

[0295] In a possible design, the message for requesting establishment or activation of the first session sent by the terminal device to the AMF may, for example, be a registration request message. Illustratively, the terminal device can request establishment of an RRC connection with the first access network device, such as sending an RRC connection establishment request to the first access network device. The terminal device can carry the registration request message to be forwarded to the AMF in the RRC connection establishment request. The registration request message can further carry the identification information of the session requested to be established or activated by the terminal device. The first access network device then forwards the registration request message to the AMF.

[0296] Optionally, the registration request message further carries the identification information of the network slices (requested NSSAI) requested to be accessed by the terminal device, for example, the network slices requested to be accessed can include the network slices identified as {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3, S-NSSAI#4, S-NSSAI#5}.

[0297] Optionally, the registration request message also carries identification information and state information of a session that has been established by the terminal device. That is, before the terminal device initiates the RRC connection establishment described above, or before the terminal device enters the RRC idle state last time, one or more sessions may have been established, and the one or more sessions are deactivated due to the terminal device entering the RRC idle state. Here, for the convenience of distinguishing and describing, the session that has been established by the terminal device is recorded as a second session. The registration request message can also carry the identification of the second session or other information that can be used to identify the second session. The registration request message can further carry information indicating the state of the second session to indicate that the second session is currently in a deactivated state.

[0298] In step 404, the AMF obtains identification information of the subscribed network slices of the terminal device from the UDM.

[0299] As mentioned above, the UDM can be used to store user data, such as subscription information, authentication / authorization information, etc. The AMF can obtain the subscription information of the terminal device from the UDM, and the subscription information contains identification information of the network slices to which the terminal device is subscribed.

[0300] One possible case is that the network slice requested by the terminal device belongs to the subscribed network slices, or the network slice requested by the terminal device is a subset of the subscribed network slices. Another possible case is that some network slices previously subscribed by the terminal device may have expired, and the network slice requested by the terminal device does not belong to the subscribed network slices.

[0301] For example, in the present embodiment, the network slices to which the terminal device is subscribed in the subscription information include network slices identified as {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3, S-NSSAI#4}. That is, the network slice identified as S-NSSAI#5 may have expired and does not belong to the subscribed network slices.

[0302] In step 405, the AMF determines the network slices allowed to be accessed by the terminal device (allowed NSSAI).

[0303] The AMF can determine the network slice allowed to be accessed by the terminal device according to the network slice requested by the terminal device, the network slice subscribed by the terminal device, and the network slice supported by the tracking area or the registration area where the terminal device is located. The network slice requested by the terminal device can be carried in the registration request message, the network slice subscribed by the terminal device can be obtained from the UDM, and the network slice supported by the tracking area or the registration area where the terminal device is located can be determined based on step 402. The AMF can determine the network slice allowed to be accessed by the terminal device based on the above three. In an implementation manner, the network slice allowed to be accessed by the terminal device can be determined by the intersection of the network slice requested by the terminal device, the network slice subscribed by the terminal device, and the network slice supported by the tracking area or the registration area where the terminal device is located.

[0304] For example, it has been shown in the above that the network slice requested by the terminal device includes the network slices identified as {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3, S-NSSAI#4, S-NSSAI#5}, the network slice subscribed by the terminal device includes the network slices identified as {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3, S-NSSAI#4}, and the network slice supported by the tracking area or the registration area where the terminal device is located includes the network slices identified as {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3}. Therefore, it can be determined that the network slice allowed to be accessed by the terminal device includes the network slices identified as {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3}.

[0305] It should be understood that the above step 405 can also be implemented by other network elements, such as the NSSF. The AMF can send the subscription information of the terminal device, the identification information of the network slice requested by the terminal device, and the identification information of the network slice supported by the tracking area or the registration area where the terminal device is located determined in step 402 to the NSSF, and the NSSF determines the network slice allowed to be accessed by the terminal device. After the NSSF determines the network slice allowed to be accessed by the terminal device, the NSSF can send the result to the AMF.

[0306] In step 406, the AMF determines the session allowed to be established or the session allowed to be activated according to the network slice allowed to be accessed by the terminal device.

[0307] Based on the network slices allowed for the terminal device to access in the above example, it can be determined that the sessions allowed to be established or the sessions allowed to be activated include the session 1, the session 2 and the session 3. Here, the allowed to be established and the allowed to be activated are respectively for the request to establish and the request to activate in the step 403 above. If the terminal device requests to establish the first session in the step 403, the AMF can determine the sessions allowed to be established in the step 406; if the terminal device requests to activate the first session in the step 403, the AMF can determine the sessions allowed to be activated in the step 406.

[0308] In the step 406, the AMF can determine whether the first session is allowed to be established or whether the first session is allowed to be activated. In the embodiment, if the first session requested to be established or requested to be activated by the terminal device is the session 1, the first session is the session allowed to be established or allowed to be activated, and the following steps can be continued to be executed. If the first session requested to be established or requested to be activated by the terminal device is the session 4, the first session does not belong to the session allowed to be established or allowed to be activated. Then, the AMF can not execute the following steps 407 to 410, but directly execute the steps 411 and 412 to send the identification information of the network slices allowed for the terminal device to access to the first access network device, so that the first access network device determines that the first session is the session not allowed to be established or not allowed to be activated.

[0309] In the step 407, the AMF sends a session management (SM) context update request message or a create session management context request message to the SMF.

[0310] For the message of requesting to establish the first session in the step 403, the AMF can send the create session management context request message to the SMF for requesting to establish the first session. For the message of requesting to activate the first session in the step 403, the AMF can send the session management context update request message to the SMF for requesting to activate the first session.

[0311] In the step 408, the SMF accepts the request of establishing the first session, or the SMF accepts the request of activating the user plane.

[0312] For example, the SMF accepting the request of establishing the first session can be a step performed for the session establishment request message of requesting to establish the first session. The SMF accepting the request of activating the user plane can be a step performed for the service request message of requesting to activate the first session.

[0313] In some cases, the SMF can reselect a new UPF because the current location of the terminal device has changed compared with the location when the first session is established.

[0314] In step 409, the SMF establishes an N4 interface session to control the UPF to establish the user plane connection of the first session; or the SMF modifies the N4 interface session to control the UPF to activate the user plane connection of the first session.

[0315] In step 410, the SMF sends a response message of the session management context creation success or a response message of the session management context update success to the AMF.

[0316] The response message of the session management context creation success may be, for example, a response to the session establishment request message for requesting to establish the first session. The response message of the session management context update success may be, for example, a response to the service request message for requesting to activate the first session.

[0317] In step 411, the AMF sends the identification information of the network slice allowed to be accessed by the terminal device to the first access network device.

[0318] For example, the AMF may, based on the registration request message of the terminal device, accept the registration of the terminal device, and send a message for establishing a context of the terminal device to the first access network device, where the message may carry the identification information of the network slice allowed to be accessed by the terminal device, the session state, and the session information to be activated.

[0319] The session state may include, for example, the state of all established sessions of the terminal device in the cell #1. In the scenario of the embodiment, the sessions of the terminal device in the cell #1 may include, for example, the deactivated session and the session to be activated.

[0320] The session information to be activated may be, for example, the identification information of the session to be activated by the terminal device and the identification information of the corresponding network slice. For example, in the embodiment, the identification information of the first session to be activated by the terminal device and the identification information of the first network slice corresponding to the first session.

[0321] The first access network device may determine the network slice allowed to be accessed by the terminal device according to the identification information of the network slice allowed to be accessed by the terminal device. In the embodiment, the identification information of the network slice allowed to be accessed by the terminal device may be, for example, {S-NSSAI#1, S-NSSAI#2, S-NSSAI#3} or other information that can be used to identify the network slice.

[0322] Optionally, as a response to the registration request message in step 403, the message further carries a registration acceptance message to be sent to the terminal device.

[0323] In step 412, the first access network device determines that the first radio resource of the cell #1 does not support the first network slice corresponding to the first session.

[0324] The first access network device can determine the first network slice corresponding to the first session according to the session information to be activated. If the network slices allowed to be accessed do not include the first network slice, the access network device can determine that the first session is a session not allowed to be established or a session not allowed to be activated. If the network slices allowed to be accessed include the first network slice, the first access network device can further determine whether the first network slice is supported by the first radio resource according to the network slices supported by the cell #1.

[0325] In this embodiment, the network slices supported by the cell #1 do not include the network slice identified as S-NSSAI #1 (i.e., the network slice corresponding to the session 1, which is an example of the first network slice), and therefore the first radio resource does not support the first network slice.

[0326] In step 413, the first access network device determines the target frequency range according to the network slices allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice.

[0327] Here, the frequency range corresponding to the first network slice can specifically refer to the frequency range supported by each neighboring cell of the first network slice, in other words, the frequency range corresponding to the first network slice in each neighboring cell. The first access network device can first determine whether the first network slice belongs to the network slices allowed to be accessed by the terminal device. In the case where the first network slice belongs to the network slices allowed to be accessed by the terminal device, the first access network device can further determine the target frequency range according to the frequency range corresponding to the first network slice in each neighboring cell. Therefore, step 413 can also be replaced by: the first access network device determines the target frequency range according to the network slices allowed to be accessed by the terminal device, the first network slice, the network slices supported by at least one neighboring cell, and the frequency range corresponding to each network slice.

[0328] It should be understood that the neighboring cells of the cell #1 can include cells with the same station as the cell #1 and cells with different stations from the cell #1. In other words, the neighboring cells of the cell #1 can include intra-station neighboring cells and inter-station neighboring cells. Therefore, the network slices supported by the at least one neighboring cell can be determined by the network slices supported by the first access network device and the network slices supported by the access network devices having the neighboring cell relationship.

[0329] It can be understood that there can be multiple cells in the neighboring cells of cell #1 supporting the first network slice, but the wireless resources corresponding to the first network slice in different cells can be different, or in other words, the corresponding frequency ranges can be different. The first access network device can preferentially select a cell in the same frequency range (i.e., the first frequency range) as cell #1. Therefore, in the case that there is a cell in the neighboring cells supporting the first network slice and the corresponding frequency range is the first frequency range, the first frequency range is preferentially selected as the target frequency range; otherwise, the frequency range corresponding to the first network slice supported by the neighboring cell is selected as the target frequency range, for example, denoted as a second frequency range, and the second frequency range is a different frequency range from the first frequency range. In other words, the target frequency range is preferentially the first frequency range, and then the second frequency range.

[0330] In this embodiment, the first network slice is a network slice identified as S-NSSAI #1, which belongs to the network slice allowed to be accessed by the terminal device. In combination with the network slices supported by the first access network device and the second access network device and the frequency ranges corresponding to the network slices in the above example, the first access network device does not support the network slice identified as S-NSSAI #1, and the frequency range supported by the second access network device for the network slice identified as S-NSSAI #1 includes the N41 frequency band and the N79 frequency band. The first frequency range supported by cell #1 is the N41 frequency band, and the first access network device can preferentially select the N41 frequency band as the target frequency range, and then select the N79 frequency band (i.e., an example of the second frequency range) as the target frequency range.

[0331] In another implementation manner, the first access network device can determine the target frequency range according to the network slice requested by the terminal device, the network slice available to the terminal device according to a subscription, and the network slice supported by the tracking area or the registration area where the terminal device is located, the first network slice, and the frequency range corresponding to the first network slice.

[0332] Here, the network slice available to the terminal device according to a subscription may, for example, be sent by a core network device (such as an AMF) to the first access network device.

[0333] When the terminal device is in a home network, the network slice available to the terminal device according to a subscription can refer to a network slice subscribed by the terminal device; when the terminal device is in a visited network, the network slice available to the terminal device according to a subscription can refer to a network slice of the visited network corresponding to the network slice subscribed by the terminal.

[0334] Since the above-mentioned network slice allowed to be accessed by the terminal device is determined according to the network slice subscribed by the terminal device, the network slice requested by the terminal device, and the network slice supported by the tracking area or the registration area where the terminal device is located, the above-mentioned two implementation manners can be considered as alternative.

[0335] In step 414, the first access network device determines the target cell according to the target frequency range.

[0336] It can be understood that the target frequency range can be the first frequency range or the second frequency range.

[0337] In an implementation, the first access network device can preferentially search for the target cell from the intra-station neighboring cells. Optionally, step 414 specifically includes that the first access network device determines the target cell from the intra-station neighboring cells supporting the target frequency range.

[0338] For example, the first access network device can first determine whether there is a cell supporting the target frequency range in the intra-station neighboring cells, for example, denoted as a first cell. In the case that the first cell exists, the first access network device can further determine whether the first cell supports the first network slice. If the first cell supports the first network slice, the first access network device can determine whether to determine the first cell as the target cell according to the signal quality of the first cell. For example, if the signal quality of the first cell meets a second preset threshold, the first cell is determined as the target cell. If the signal quality of the first cell is lower than the second preset threshold, or the first cell does not support the first network slice, or the intra-station neighboring cells (i.e., the cells served by the first access network device) only include the first cell, the first access network device can determine the target cell in the inter-station neighboring cells.

[0339] Optionally, step 414 specifically includes that the first access network device determines the target cell from the inter-station neighboring cells supporting the target frequency range.

[0340] For example, step 414 can further include:

[0341] Step 4141, the first access network device determines a radio measurement parameter according to the target frequency range;

[0342] Step 4142, the first access network device sends the radio measurement parameter to the terminal device, and the radio measurement parameter is used for the terminal device to measure the signal quality of the neighboring cell;

[0343] Step 4143, the terminal device reports the measurement result of the signal quality of the neighboring cell to the first access network device;

[0344] Step 4144, the first access network device determines the target cell according to the measurement result of the signal quality of the neighboring cell.

[0345] Similar to the process of searching for a cell from the intra-station neighboring cells above, the first access network device can first determine whether there is a first cell supporting the first frequency range in the inter-station neighboring cells. In the case that there is the first cell, the first access network device can determine the radio measurement parameter (i.e., the first radio measurement parameter) according to the first frequency range, and send the first radio measurement parameter to the terminal device, so as to facilitate the terminal device to measure the signal quality of the first cell based on the first frequency range. The first access network device can further determine whether the first cell can be the target cell based on the measurement result reported by the terminal device. For example, in the case that the signal quality of the first cell meets the second preset threshold, the first cell is determined as the target cell.

[0346] If the signal quality of the first cell is lower than the second preset threshold, the first access network device can further determine whether there is another selectable frequency range, and continue to search for the target cell in the case that there is another selectable frequency range.

[0347] For example, if there is a cell supporting the first network slice in the neighboring cells of the cell #1, and the corresponding frequency range is the second frequency range, the first access network device can search for the target cell based on the second frequency range. The first access network device can preferentially search for the target cell in the intra-station neighboring cells, and secondarily search for the target cell in the inter-station neighboring cells.

[0348] The specific process of the first access network device searching for the target cell in the intra-station neighboring cells based on the second frequency range is the same as the specific process of the first access network device searching for the target cell in the intra-station neighboring cells based on the first frequency range described above. For brevity, it will not be repeated here.

[0349] The specific process of the first access network device searching for the target cell in the inter-station neighboring cells based on the second frequency range can be realized by performing steps 4141 to 4144, and the specific process can be referred to the related description of steps 4141 to 4144 above.

[0350] The difference is that the first access network device can determine the radio measurement parameter (i.e., the second radio measurement parameter) according to the second frequency range, and send the second radio measurement parameter to the terminal device, so as to facilitate the terminal device to measure the signal quality of the neighboring cells based on the second frequency range. The first access network device can further determine the target cell based on the measurement result reported by the terminal device.

[0351] It should be understood that in the case that the cells served by the first access network device only include the cell #1, or in other words, the cell #1 does not have intra-station neighboring cells, the first access network device can directly determine the target cell from the inter-station neighboring cells, i.e., perform steps 4141 to 4144 above.

[0352] In addition, the wireless measurement parameter (the first wireless measurement parameter or the second wireless measurement parameter) sent by the first access network device to the terminal device may, for example, be carried in the registration accept message forwarded by the first access network device to the terminal device in step 411, or may also be sent separately. The present application does not limit this.

[0353] The first wireless measurement parameter and the second wireless measurement parameter may be separately sent based on different values of the target frequency range, or may be simultaneously sent to the terminal device. The present application does not limit this.

[0354] It should also be understood that the specific process of determining the target cell by the first access network device from the intra-station neighboring cells and / or the inter-station neighboring cells can refer to the related description in step 304 of method 300 above, and will not be repeated here for brevity.

[0355] It should be noted that the above is a detailed description of the process of determining the target cell by the first access network device, taking the first session as an example for convenience and illustration. In fact, the session requested by the terminal device to the first access network device to establish or activate is not necessarily limited to the first session. The terminal device may request the first access network device to establish and / or activate multiple sessions in parallel. In this case, the target cell determined by the first access network device for the terminal device should consider the multiple sessions comprehensively in order to activate the multiple sessions. Therefore, when determining the target cell, the first access network device should make the network slices corresponding to the multiple sessions requested by the terminal device to establish and / or activate as much as possible to be supported by the target cell, and all of them are able to access the wireless resources supported by the target cell respectively.

[0356] In other words, if there is a cell whose supported network slices include the multiple sessions requested by the terminal device to establish and / or activate, and the multiple network slices can all access the same wireless resources in the cell, then the cell is preferentially selected as the target cell.

[0357] For example, if the sessions requested by the terminal device to establish and / or activate include session 1 and session 3, which correspond to network slices identified as S-NSSAI#1 and S-NSSAI#3 respectively.

[0358] From the network slices supported by the first and second access network devices respectively and the frequency ranges corresponding to the network slices, it can be seen that the network slices supported by the first access network device include the network slice identified as S-NSSAI#2, and there is no cell in the intra-station neighboring cells of the cell #1 that can simultaneously support the network slices corresponding to the session 1 and the session 3. While the network slices supported by the second access network device include the network slices identified as S-NSSAI#1, S-NSSAI#2 and S-NSSAI#3, the target cell can be found from the inter-station neighboring cells of the cell #1. The first access network device can further determine, according to the frequency ranges corresponding to the network slices supported by the second access network device, that the N79 frequency band can simultaneously support the two network slices, and thus the N79 frequency band is the target frequency range. The first access network device can find the target cell from the inter-station neighboring cells of the cell #1 based on the N79 frequency band.

[0359] It should be understood that the above is described in conjunction with specific examples to facilitate understanding of the process of determining the target frequency range and thus the target cell by the first access network device. It should be understood that the above examples of the correspondence between each session and network slice, the network slices supported by each access network device, and the frequency ranges corresponding to each network slice are only examples and should not constitute any limitation on the present application.

[0360] If the first access network device cannot find such a cell that can support the multiple sessions requested by the terminal device to be established and / or activated, the first access network device can select a cell supporting part of the sessions as the target cell according to the load of the radio resources of each neighboring cell and the priority of each radio resource. Alternatively, the first access network device can also select a cell supporting the network slice corresponding to the session with high priority as the target cell according to the priority of the multiple sessions.

[0361] As mentioned above, the terminal device can have established one or more sessions before requesting to establish an RRC connection with the first access network device, and the one or more established sessions are in the deactivated state. The terminal device can carry the information of the one or more established sessions when sending the RRC connection establishment request. The first access network device can further combine the one or more established sessions when determining the target cell for the terminal device, so as to support the one or more established sessions in the selected target cell as much as possible.

[0362] For example, the session currently requested by the terminal device to be established or activated includes a first session, and the corresponding network slice is a first network slice; the session currently deactivated by the terminal device includes a second session, and the corresponding network slice is a second network slice. When determining the target cell for the terminal device, the first access network device should select a cell that can support the first network slice and the second network slice as the target cell as much as possible.

[0363] If the first access network device cannot find such a cell that can support the first network slice and the second network slice, the first network slice corresponding to the first session currently requested to be established or requested to be activated can be prioritized, and a cell that can support the first network slice is selected as the target cell.

[0364] It should be understood that the various possible cases listed above are only examples and should not constitute any limitation on the present application.

[0365] In step 415, the first access network device controls the terminal device to switch to the target cell.

[0366] The target cell determined by the first access network device for the terminal device can be a cell served by the first access network device, or can not be a cell served by the first access network device. The terminal device can perform an intra-site handover procedure, or can perform a cross-site handover procedure. Since the intra-site handover procedure and the cross-site handover procedure have been described in detail in step 305 of the method 300 above, for the sake of brevity, they will not be repeated here.

[0367] It should be understood that the specific procedure of the terminal device performing the cross-site handover can refer to the prior art, and for the sake of brevity, it will not be described in detail here.

[0368] In step 416, the second access network device and the terminal device establish a DRB for the successfully switched session over the air interface.

[0369] It should be understood that the successfully switched session may, for example, include the first session described above, or may also include the first session and the second session described above. The present application does not limit this.

[0370] In step 417, the AMF switches the user plane path of the first session to the second access network device.

[0371] In step 418, the AMF sends N3 interface endpoint information to the second access network device.

[0372] In step 419, the second access network device and the core network establish a user plane connection and activate the first session.

[0373] In this embodiment, the user plane connection is the N3 interface connection between the second access network device and the UPF. Based on the establishment of the N3 interface connection between the second access network device and the UPF, the user plane of the first session is activated. Thereafter, the terminal device can receive and transmit service data through the activated first session.

[0374] It should be understood that Figure 4Steps 415 to 419 are described by taking the terminal device performing inter-site handover as an example. However, this should not constitute any limitation on the present application. In the intra-site handover procedure, the procedure involving inter-site handover in step 415 and steps 416 to 419 do not necessarily have to be performed.

[0375] Based on the technical solution described above, when the first session requested to be established or activated by the terminal device cannot be supported by the radio resources of the source cell, the first access network device serving the source cell can determine a target cell for the terminal device according to the first network slice corresponding to the first session, the network slices supported by each of the at least one neighboring cell, and the radio resources corresponding to each network slice, and control the terminal device to hand over to the target cell. Therefore, the terminal device can be timely handed over to the target cell in the case where the first session requested to be established or activated cannot be supported by the radio resources of the source cell and there is a target cell that can be handed over to, so that the session request of the terminal device can be responded to in a timely manner, and the first session can be activated within a short time, which is beneficial to improving user experience.

[0376] Figure 5 FIG. 6 is another schematic flowchart of a communication method according to an embodiment of the present application. Figure 5 The method 500 shown can include steps 501 to 515.

[0377] For ease of understanding and description, first, the scenario of the method 500 is described as follows: the terminal device in the method 500 has established one or more sessions in a cell #1 served by the first access network device, but part of the one or more sessions can be in a deactivated state. The terminal device and the first access network device each reserve the context of the sessions, and no user plane connection is activated.

[0378] Hereinafter, the first session is taken as an example of a session requested to be activated or established to describe the embodiment.

[0379] It should be understood that the steps performed for the session requested to be established in the following steps are basically similar to the steps performed for the session requested to be activated. When there are differences, the steps performed for the session requested to be established and the session requested to be activated are described separately in each step.

[0380] In addition, it is assumed in the embodiment that the network slices supported by the first access network device and the frequency ranges corresponding to each network slice include: {S-NSSAI #2, (N41)}, and the frequency range supported by the cell #1 served by the first access network device is the N41 frequency band.

[0381] In the method 500, step 507 can correspond to step 210 in the method 200, and shows one possible implementation manner in which the first access network device determines that the terminal device meets the cell handover condition in step 210.

[0382] Steps 509 and 510 can correspond to step 220 in method 200, showing possible implementation manners of step 220 in which the first access network device determines the target cell. In step 509, the first access network device can determine the target frequency range according to the network slices allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice. In step 510, the first access network device can determine the target cell according to the target frequency range. One possible implementation manner of step 510 is that the first access network device determines the target cell from the in-station neighboring cells supporting the target frequency range. Another possible implementation manner of step 510 is that the target cell is determined from the out-station neighboring cells supporting the target frequency range. In the case of determining the target cell from the out-station neighboring cells supporting the target frequency range, the method further comprises: determining, by the first access network device, the radio measurement parameters according to the target frequency range; and sending, by the first access network device, the radio measurement parameters to the terminal device, the radio measurement parameters being used for the terminal device to measure the signal quality of the neighboring cells, and the measurement of the signal quality of the neighboring cells by the terminal device being used for the determination of the target cell.

[0383] Step 511 can correspond to step 230 in method 200, showing possible implementation manners of step 230 in which the first access network device controls the terminal device to handover to the target cell. Corresponding to step 510, one possible implementation manner of step 511 is that the first access network device controls the terminal device to perform in-station handover. Another possible implementation manner of step 511 is that the first access network device controls the terminal device to perform cross-station handover. In the case of performing cross-station handover, the method further comprises: sending, by the first access network device, a request message to the second access network device, the request message carrying the identification information of the first session and the identification information of the first network slice; receiving, by the first access network device, the RRC parameters for handover from the second access network device; and sending, by the first access network device, the RRC parameters to the terminal device. Optionally, the RRC parameters are associated with the first network slice, the network slices supported by the second access network device, and the radio resources corresponding to the network slices supported by the second access network device.

[0384] The method 500 will be described in detail below in combination with a specific flow.

[0385] In step 501, the terminal device sends a message for requesting activation or for requesting establishment of a first session to an AMF via a first access network device, the message carrying identification information of the first session for which activation or establishment is requested.

[0386] In a possible design, the message is a service request message to request activation of the first session. Exemplarily, the terminal device can send, to the first access network device, an RRC connection setup request message carrying a service request message to be sent to the AMF, the service request message being used to request activation of the first session. For example, the service request message can carry identification information of the first session. The first access network device then forwards the service request message to the AMF.

[0387] In another possible design, the message is a session establishment request to request establishment of the first session. The session establishment request can also be carried in the RRC connection setup request message to request establishment of the first session. The session establishment request can also carry identification information of the first session. The first access network device then forwards the session request message to the AMF.

[0388] In step 502, the AMF sends a session management context update request message or a create session management context request message to the SMF.

[0389] For the service request message requesting activation of the first session, the session management context update request message sent by the AMF to the SMF is used to request activation of the first session. For the session establishment request message requesting establishment of the first session, the create session management context request message sent by the AMF to the SMF is used to request establishment of the first session.

[0390] In step 503, the SMF accepts the request for user plane activation or accepts the request for establishment of the first session.

[0391] For example, the SMF accepting the request for user plane activation can be a step performed for the service request message requesting activation of the first session. The SMF accepting the session establishment request can be a step performed for the session establishment request message requesting establishment of the first session.

[0392] In some cases, the SMF can reselect a new UPF because the current location of the terminal device has changed compared with the location when the first session is established.

[0393] In step 504, the SMF modifies an N4 interface session to control the UPF to activate the user plane connection of the first session, or establishes an N4 interface session to control the UPF to establish the user plane connection of the first session.

[0394] In step 505, the SMF sends a response message of session management context update success or a response message of create session management context success to the AMF.

[0395] The response message of the success of the session management context update may be, for example, a response to a service request message requesting activation of the first session. The response message of the success of the creation of the session management context may be, for example, a response to a session establishment request message requesting establishment of the first session.

[0396] In step 506, the AMF sends an N2 interface request message to the first access network device, the N2 interface request message carrying identification information of the first network slice corresponding to the first session requested to be activated or established. For example, the first session requested to be activated by the terminal device is session 1, and the first network slice corresponding thereto is a network slice identified as S-NSSAI#1; the first session requested to be established by the terminal device is session 2, and the first network slice corresponding thereto is a network slice identified as S-NSSAI#2.

[0397] In step 507, the first access network device determines that the first radio resource of cell #1 does not support the first network slice corresponding to the first session.

[0398] For example, if the first network slice corresponding to the first session is a network slice identified as S-NSSAI#2, the first radio resource of cell #1 supports the first network slice. In this case, the terminal device can continue to activate or establish the first session in the source cell according to the prior art process. Since this embodiment does not involve this process, it will not be described here.

[0399] For another example, if the first network slice corresponding to the first session is a network slice identified as S-NSSAI#1, the first radio resource of cell #1 does not support the first network slice. In this case, cell #1 is the source cell of the terminal device, and the first access network device needs to determine a target cell for the terminal device.

[0400] In step 508, the first access network device suspends activation or establishment of the user plane connection for the first session.

[0401] Since the first access network device determines that the first radio resource of cell #1 does not support the first network slice corresponding to the first session, the terminal device needs to perform cell switching. Therefore, the first access network device can send indication information indicating processing of a handover process to the AMF, and suspend activation or establishment of the user plane connection for the first session. After receiving the indication information sent by the first access network device, the AMF can later reattempt to send the N2 interface request message in step 506 to continue activation or establishment of the user plane connection.

[0402] In step 509, the first access network device determines a target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and the frequency range corresponding to the first network slice.

[0403] It should be understood that the neighboring cells of cell #1 can include cells co-sited with cell #1 and cells non-co-sited with cell #1. In other words, the neighboring cells of cell #1 can include both intra-site neighboring cells and inter-site neighboring cells. Therefore, the network slices supported by the at least one neighboring cell can be determined by the network slices supported by the first access network device and the network slices supported by the access network devices having the neighboring cell relationship. Therefore, the frequency range corresponding to the first network slice can specifically refer to the frequency range supported by each neighboring cell supporting the first network slice. In other words, step 509 can also be replaced by: determining, by the first access network device, the target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, the network slice supported by the at least one neighboring cell, and the frequency range corresponding to each network slice.

[0404] In addition, step 509 can also be implemented by the following steps: the first access network device can determine the target frequency range according to the network slice requested by the terminal device, the network slice available to the terminal device according to the subscription, the network slice supported by the tracking area or the registration area where the terminal device is located, the first network slice, and the frequency range corresponding to the first network slice. Since the network slice available to the terminal device according to the subscription has been described in detail above, for brevity, it will not be repeated here.

[0405] As mentioned above, the first access network device can preferentially select a cell in the same frequency range (i.e., the first frequency range) as cell #1. Therefore, in the case where there is a cell in the neighboring cells supporting the first network slice and the corresponding frequency range is the first frequency range, the first frequency range is preferentially selected as the target frequency range; otherwise, the other frequency range corresponding to the first network slice supported by the neighboring cells is selected as the target frequency range, for example, denoted as the second frequency range, and the second frequency range is different from the first frequency range. In other words, the target frequency range is preferentially the first frequency range, and then the second frequency range.

[0406] It should be understood that the specific process of step 509 can refer to the related description of step 413 in method 400 above for brevity, which will not be repeated here.

[0407] In step 510, the first access network device determines a target cell according to the target frequency range.

[0408] In step 511, the first access network device controls the terminal device to hand over to the target cell.

[0409] In step 512, the second access network device and the terminal device establish a DRB for the successfully handed over session over the air interface.

[0410] In step 513, the AMF switches the user plane path of the first session to the second access network device.

[0411] In step 514, the AMF sends N3 interface endpoint information to the second access network device.

[0412] In an implementation, the AMF can send a second request message to the second access network device, which is not sent in step 506, and carry the N3 interface endpoint information in the second request message.

[0413] In step 515, the second access network device and the core network establish a user plane connection and activate the user plane of the first session.

[0414] The specific processes of steps 510 to 515 are similar to those of steps 414 to 419 in method 400 described above, and are not repeated here for brevity.

[0415] It should be understood that, Figure 5 Steps 511 to 515 are described by taking the terminal device performing cross-site handover as an example. However, this should not constitute any limitation on the present application. In the intra-site handover process, the process related to cross-site handover in step 511 and steps 512 to 515 do not necessarily have to be performed.

[0416] It should be noted that the above describes in detail the process of the first access network device determining the target cell by taking the first session as an example for the convenience of understanding and description. In fact, the session that the terminal device requests the first access network device to establish or activate is not necessarily limited to the first session. The terminal device can request the first access network device to establish and / or activate multiple sessions in parallel. In this case, the target cell determined by the first access network device for the terminal device should take into account the multiple sessions in order to activate the multiple sessions. Therefore, when determining the target cell, the first access network device should make the network slices corresponding to the multiple sessions requested by the terminal device to establish and / or activate as much as possible to be supported by the target cell, and all of them are able to access the wireless resources supported by the target cell.

[0417] In other words, if there is a cell whose supported network slices include the multiple sessions requested by the terminal device to establish and / or activate, and the multiple network slices are all able to access the same wireless resources in the cell, the cell is preferentially selected as the target cell.

[0418] It should also be noted that the terminal device can have established one or more sessions before requesting the establishment or activation of the first session, and the one or more established sessions can include activated sessions and / or deactivated sessions. When determining the target cell for the first session currently requested to establish or activate, the first access network device can further combine the one or more established sessions in order to support as many as possible of the one or more established sessions in the selected target cell.

[0419] For example, the session currently requested by the terminal device to establish or activate includes a first session, and the corresponding network slice is a first network slice; the session currently activated by the terminal device includes session #3 (an example of a second session), and the corresponding network slice is network slice #3; the session currently deactivated by the terminal device includes session #4 (another example of a second session), and the corresponding network slice is network slice #4. When the first access network device determines the target cell for the terminal device, a cell capable of supporting the first network slice, the network slice #3 and the network slice #4 should be selected as the target cell as much as possible.

[0420] If the first access network device cannot find such a cell capable of simultaneously supporting the first network slice, the network slice #3 and the network slice #4, the target cell can be selected according to the priority of the session, so that the selected target cell can support as many sessions with high priority as possible.

[0421] Based on the above technical solution, when the first session requested by the terminal device to activate cannot be supported by the radio resource of the source cell, the first access network device serving the source cell can determine the target cell for the terminal device according to the first network slice corresponding to the first session, the network slice supported by each adjacent cell and the radio resource corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can be switched to the target cell in time in the case that the first session requested to establish or activate cannot be supported by the radio resource of the source cell and there is a switchable target cell, so that the first session can be successfully activated, the session request of the terminal device can be responded in time, and the user experience is improved.

[0422] Figure 6 FIG. 6 is another schematic flowchart of a communication method according to an embodiment of the present application. Figure 6 The method 600 shown can include steps 601 to 612.

[0423] For the convenience of understanding and description, first, the following description is made on the scenario to which the method 600 is applied: the terminal device is in an RRC connected state with the first access network device. The terminal device is in a cell #1 served by the first access network device, and has established a session, for example, session 1, corresponding to a network slice identified as S-NSSAI #1. The terminal device hopes to establish a new session or activate a session, for example, session 3. The network slice corresponding to session 3 is a network slice identified as S-NSSAI #3. It can be understood that session 3 is an example of a first session, and the network slice identified as S-NSSAI #3 is an example of a first network slice.

[0424] It should be understood that the steps performed in the following steps for requesting to establish a session are substantially similar to the steps performed for requesting to activate a session. Where there are differences, the steps for requesting to establish a session and the steps for requesting to activate a session are separately described.

[0425] In the method 600, the step 602 can correspond to the step 210 in the method 200, and illustrates one possible implementation of the step 210 in which the first access network device determines that the terminal device satisfies the cell handover condition.

[0426] The steps 603 and 609 can correspond to the step 220 in the method 200, and illustrate possible implementations of the step 220 in which the first access network device determines the target cell. In the step 603, the first access network device can determine the target frequency range according to the network slice to which the terminal device is allowed to access, the first network slice, and the frequency range corresponding to the first network slice. In the step 604, the first access network device determines the target cell from the in-station neighboring cells supporting the target frequency range. In the steps 606 to 609, the first access network device determines the target cell from the out-station neighboring cells supporting the target frequency range. Determining the target cell from the out-station neighboring cells supporting the target frequency range specifically can include: the step 606, in which the first access network device determines the radio measurement parameter according to the target frequency range; the step 607, in which the first access network device sends the radio measurement parameter to the terminal device; the step 608, in which the terminal device reports the measurement result of the signal quality of at least one neighboring cell to the first access network device; and the step 609, in which the first access network device determines the target cell according to the measurement result of the signal quality of at least one neighboring cell.

[0427] The step 610 can correspond to the step 230 in the method 200, and illustrates possible implementations of the step 230 in which the first access network device controls the terminal device to hand over to the target cell. Corresponding to the step 604, the first access network device controls the terminal device to perform in-station handover. Corresponding to the step 609, the first access network device controls the terminal device to perform cross-station handover. In the case of performing cross-station handover, the method further includes: the first access network device sends a request message to the second access network device, the request message carrying the identification information of the first session and the identification information of the first network slice; the first access network device receives the RRC parameter for handover from the second access network device; and the first access network device sends the RRC parameter to the terminal device. Optionally, the RRC parameter is associated with the first network slice, the network slice supported by the second access network device, and the radio resource corresponding to the network slice supported by the second access network device.

[0428] The method 600 is described in detail below in combination with a specific flow.

[0429] In step 601, the terminal device sends, to the first access network device, a message for requesting establishment or activation of the first session, where the message carries identification information of the first network slice.

[0430] In a possible design, the message is a session establishment request message for requesting establishment of the first session. For example, the terminal device can send, to the first access network device, a session establishment request message, where the session establishment request message carries identification information of the first network slice. For example, the RRC layer of the request message carries the identification information of the first network slice. In this embodiment, the identification information of the first network slice can be S-NSSAI#3. Since the first network slice corresponds to the first session, the identification information of the first network slice is carried in the request message, that is, a session is requested to be established or a session in the first network slice is activated by accessing the first network slice.

[0431] In another possible design, the message is a session activation request message for requesting activation of the first session. For example, the terminal device can send, to the first access network device, a session activation request message, where the session activation request message carries identification information of the first network slice.

[0432] In step 602, the first access network device determines that the first radio resource of the cell #1 does not support the first network slice corresponding to the first session.

[0433] The first access network device can determine, according to the identification information of the first network slice, whether the first radio resource supported by the cell #1 supports the first network slice.

[0434] In step 603, the first access network device determines a target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and a frequency range corresponding to the first network slice.

[0435] The network slice allowed to be accessed by the terminal device has been described in detail in step 405 of the method 400 above. For brevity, the description is not repeated here.

[0436] The frequency range corresponding to the first network slice can be the frequency range supported by each neighboring cell supporting the first network slice, in other words, the frequency range corresponding to the first network slice in each neighboring cell. Therefore, step 602 can be replaced by: the first access network device determines a target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, the network slice supported by at least one neighboring cell, and the frequency range corresponding to each network slice.

[0437] The first access network device can receive, from the AMF, identification information of the network slice allowed to be accessed by the terminal device, and determine whether the first network slice belongs to the network slice allowed to be accessed by the terminal device. In a case where the first network slice belongs to the network slice allowed to be accessed by the terminal device, the first access network device can further determine the target frequency range according to the frequency range corresponding to the first network slice in each neighboring cell.

[0438] In another implementation, the step 603 can also be replaced by: the first access network device determines the target frequency range according to the network slice requested by the terminal device, the network slice that can be used by the terminal device according to a subscription, and the network slice supported by a tracking area or a registration area where the terminal device is located, the first network slice, and the frequency range corresponding to the first network slice.

[0439] It should be understood that the specific process of determining the target frequency range by the first access network device has been described in detail in the step 410 of the method 400 above, and will not be repeated here for brevity.

[0440] In the step 604, the first access network device determines a target cell from the intra-station neighboring cells according to the target frequency range.

[0441] The first access network device can determine whether there is a cell that can be used as the target cell in the intra-station neighboring cells by performing the step 604.

[0442] For example, the first access network device can first determine whether there is a first cell supporting the target frequency range in the intra-station neighboring cells of the cell #1. In a case where the first cell exists, the first access network device can further determine whether the first cell supports the first network slice. In a case where the first cell supports the first network slice, the first access network device can determine whether the first cell can be used as the target cell according to the signal quality of the first cell. In a case where the signal quality of the first cell meets a second preset threshold, the first access network device determines that the first cell is the target cell. Thereafter, the intra-station handover process in the step 610 can be performed.

[0443] In a case where the intra-station neighboring cells of the cell #1 do not have the first cell, or in a case where the first cell does not support the first network slice, or in a case where the signal quality of the first cell is lower than the second preset threshold, the first access network device can determine that there is no cell that can be used as the target cell in the intra-station neighboring cells.

[0444] In the step 605, the first access network device can send a rejection message to the terminal device, and suspend the establishment or activation of the first session.

[0445] In an implementation, the first access network device can send a rejection message to the terminal device to inform the terminal device that the first access network device rejects to establish or activate the first session.

[0446] As a response to the session establishment request message in step 601 above, the first access network device can send a rejection message to the terminal device for the service establishment request message to reject to establish the first session. As a response to the session activation request message in step 601 above, the first access network device can send a rejection message to the terminal device for the session activation response message to reject to activate the first session.

[0447] In step 606, the first access network device determines the radio measurement parameter according to the target frequency range.

[0448] In step 607, the first access network device sends the radio measurement parameter to the terminal device.

[0449] In an implementation, the radio measurement parameter can be carried in the rejection message above to trigger the terminal device to measure the signal quality of at least one neighboring cell.

[0450] In step 608, the terminal device measures the signal quality of at least one neighboring cell based on the radio measurement parameter and reports the measurement result of the signal quality of at least one neighboring cell to the first access network device.

[0451] In step 609, the first access network device determines the target cell according to the measurement result of the signal quality of at least one neighboring cell.

[0452] The target cell determined by the first access network device is a target cell determined from the inter-site neighboring cells. The terminal device needs to handover the access network device.

[0453] In an example, the first session requested by the terminal device to establish is session 3 and the first network slice is a network slice identified as S-NSSAI#3. It is assumed that the network slices supported by the first access network device and the frequency ranges corresponding to the network slices include: {S-NSSAI#1, (N41)} and {S-NSSAI#2, (N41, N79)}, and the network slices supported by the second access network device and the frequency ranges corresponding to the network slices include: {S-NSSAI#1, (N41, N79)}, {S-NSSAI#2, (N79)} and {S-NSSAI#3, (N79)}.

[0454] It can be seen that the identity of the network slice supported by the first access network device does not include S-NSSAI#3, so there is no cell in the intra-station neighboring cells of cell #1 that can support the network slice of session 3. However, the identity of the network slice supported by the second access network device includes S-NSSAI#3, so there is a cell in the inter-station neighboring cells of cell #1 that can support the network slice of session 3. The first access network device can search for the target cell from the inter-station neighboring cells of cell #1. The first access network device can further determine, according to the frequency range corresponding to the network slice, that the frequency range corresponding to the network slice identified as S-NSSAI#3 in the second access network device is the N79 frequency band, and thus the target frequency range is the N79 frequency band. Thereafter, the first access network device can search for the target cell from the inter-station neighboring cells of cell #1 based on the N79 frequency band. The target cell can provide access services of the network slices identified as S-NSSAI#1 and S-NSSAI#3 in the N79 frequency band.

[0455] Further, if the terminal device has established session 1 in cell #1, and the corresponding network slice is the network slice identified as S-NSSAI#1. The first access network device can determine the target frequency range in combination with the network slices corresponding to session 1 and session 3. For example, session 1 corresponds to the network slice identified as S-NSSAI#1, and session 3 corresponds to the network slice identified as S-NSSAI#3, and the common frequency range corresponding to the second access network device is the N79 frequency band, so the target frequency range is the N79 frequency band. Thereafter, the first access network device can search for the target cell from the inter-station neighboring cells of cell #1 based on the N79 frequency band. The target cell can provide access services of the network slices identified as S-NSSAI#1 and S-NSSAI#3 in the N79 frequency band.

[0456] It should be understood that the above is for the convenience of understanding, and the process of determining the target frequency range and thus the target cell by the first access network device is described in combination with specific examples. The correspondence between each session and network slice, the network slices supported by each access network device, and the frequency range corresponding to each network slice in the examples are only examples and should not constitute any limitation on the present application.

[0457] It should also be understood that in the case where there are multiple sessions requested to be established and / or activated, the related content of determining the target cell for the terminal device by the first access network device has been described in detail in the above methods 400 and 500, and for the sake of brevity, will not be repeated here.

[0458] It should also be understood that in the case where there is one or more established sessions (for example, including activated and / or deactivated sessions) in the terminal device, the related content of determining the target cell for the terminal device by the first access network device has also been described in detail in the above methods 400 and 500, and for the sake of brevity, will not be repeated here.

[0459] In step 610, the first access network device controls the terminal device to switch to the target cell.

[0460] As mentioned above, the first access network device can control the terminal device to perform an intra-site handover procedure or a cross-site handover procedure, depending on whether the target cell is a cell served by the first access network device. It should be understood that since the intra-site handover procedure and the cross-site handover procedure have been described in detail in step 305 of the above method 300 respectively, and the specific procedures of the terminal device performing the intra-site handover and the cross-site handover can refer to the prior art, for the sake of brevity, they will not be described in detail here.

[0461] In step 611, the terminal device sends a message to the second access network device for requesting establishment or activation of the first session, which carries the identification information of the first network slice corresponding to the first session.

[0462] The message sent by the terminal device to the second access network device is similar to the message sent by the terminal device to the first access network device in step 601 for requesting establishment or activation of the first session, which carries the identification information of the first network slice at the RRC layer. The request message is used to request establishment or activation of the first session.

[0463] In step 612, the terminal device initiates a session establishment procedure through the second access network device.

[0464] In this way, the first session is successfully established. The terminal device can normally transmit service data through the first session.

[0465] It should be understood that step 612 does not necessarily have to be performed based on different scenarios of requesting establishment or activation of the first session. For example, in the scenario of activating the first session, step 612 can be omitted. After the terminal device switches to the second access network device, the activation of the first session is completed.

[0466] It should also be understood that the above steps are not necessarily performed. For example, if the target cell is an intra-site neighboring cell of cell #1, steps 604 to 608 to 611 above do not necessarily have to be performed.

[0467] Based on the technical solution, when the first session requested by the terminal device to be established cannot be supported by the radio resource of the source cell, the first access network device serving the source cell can determine a target cell for the terminal device according to the first network slice corresponding to the first session, the network slices supported by each of the at least one neighboring cell, and the radio resource corresponding to each network slice, and control the terminal device to switch to the target cell. Therefore, the terminal device can be switched to the target cell in time in the case that the first session requested to be established cannot be supported by the radio resource of the source cell and there is a target cell that can be switched to, so that the first session can be successfully established and activated, the session request of the terminal device can be responded to in time, and the user experience is improved.

[0468] Figure 7 FIG. 7 is another schematic flowchart of a communication method according to an embodiment of the present application. Figure 7 The method 700 shown can include steps 701 to 713.

[0469] The scenario to which the method 700 is applied is the same as the scenario to which the method 600 is applied, and can refer to the scenario described above in the method 600. For brevity, the description is not repeated here. The difference is that in the method 700, the terminal device requests to establish a first session.

[0470] In the method 700, step 706 can correspond to step 210 in the method 200, and shows one possible implementation of step 210 in which the first access network device determines that the terminal device satisfies the cell switching condition.

[0471] Steps 707 and 709 can correspond to step 220 in the method 200, and show possible implementations of step 220 in which the first access network device determines the target cell. In step 707, the first access network device can determine a target frequency range according to the network slice allowing the terminal device to access, the first network slice, and the frequency range corresponding to the first network slice. In step 709, the first access network device determines the target cell according to the target frequency range. One possible implementation of step 709 is that the first access network device determines the target cell from the in-station neighboring cells supporting the target frequency range. Another possible implementation of step 709 is that the target cell is determined from the out-station neighboring cells supporting the target frequency range. In the case that the target cell is determined from the out-station neighboring cells supporting the target frequency range, the method further includes: the first access network device determines a radio measurement parameter according to the target frequency range; and the first access network device sends the radio measurement parameter to the terminal device, the radio measurement parameter being used for the terminal device to measure the signal quality of the neighboring cell, and the measurement of the signal quality of the neighboring cell by the terminal device being used for the determination of the target cell.

[0472] Step 710 can correspond to step 230 in method 200, and shows a possible implementation of step 230 in which the first access network device controls the terminal device to perform handover to the target cell. Corresponding to step 709, one possible implementation of step 710 is that the first access network device controls the terminal device to perform an intra-site handover. Another possible implementation of step 710 is that the first access network device controls the terminal device to perform a cross-site handover. In the case of performing a cross-site handover, the method further includes: the first access network device sending, to the second access network device, a request message carrying the identification information of the first session and the identification information of the first network slice; the first access network device receiving, from the second access network device, an RRC parameter for handover; and the first access network device sending the RRC parameter to the terminal device. Optionally, the RRC parameter is associated with the first network slice, the network slices supported by the second access network device, and the radio resources corresponding to the network slices supported by the second access network device.

[0473] The method 700 will be described in detail below in combination with a specific flow.

[0474] In step 701, the terminal device sends, to the AMF via the first access network device, a message requesting to establish a first session, the message carrying identification information of the first session.

[0475] In one implementation, the terminal device can carry the identification information of the first session in the message sent to the first access network device, without carrying the identification information of the first network slice. The first access network device can forward the session establishment request message to the AMF. In this embodiment, the identification information of the first session can be, for example, session 3.

[0476] As described in method 600, in one possible design, the message is a session establishment request message.

[0477] In step 702, the AMF and the SMF create a session management context for the first session requested to be established.

[0478] For example, the AMF can select an SMF, and create a session management context for the first session with the selected SMF.

[0479] In step 703, the SFM and the UPF establish an N4 interface session.

[0480] For example, the SMF can select a UPF, and send an N4 session establishment request to the selected UPF to request to establish an N4 session.

[0481] In step 704, the SMF sends the identification information of the first network slice to the AMF.

[0482] The SMF can send an N1N2 message transfer to the AMF, where the N2 SM information is carried. The N2 SM information contains information of the newly created session, including the identification information of the first network slice corresponding to the first session. In this embodiment, the identification information of the first network slice can be S-NSSAI#3.

[0483] In step 705, the AMF sends the identification information of the first network slice to the first access network device.

[0484] The AMF can forward the N2 SM information to the first access network device based on the received N2 SM information. As described above, the N2 SM information carries the identification information of the first network slice. In this way, the first access network device can determine the first network slice corresponding to the first session requested by the terminal device to establish.

[0485] In a possible design, the N2 SM information is carried in an N2 interface request message.

[0486] In step 706, the first access network device determines that the first radio resource of the cell #1 where the terminal device currently locates does not support the first network slice corresponding to the first session.

[0487] The first access network device can determine whether the first radio resource supported by the cell #1 supports the first network slice according to the identification information of the first network slice.

[0488] In step 707, the first access network device determines the target frequency range according to the network slice allowed to be accessed by the terminal device, the first network slice, and the operating frequency corresponding to the first network slice.

[0489] In another implementation manner, step 707 can also be replaced by: the first access network device determines the target frequency range according to the network slice requested by the terminal device, the network slice that can be used by the terminal device according to the subscription, the network slice supported by the tracking area or the registration area where the terminal device locates, the first network slice, and the frequency range corresponding to the first network slice. It should be understood that the specific process of determining the target frequency range by the first access network device has been described in detail in step 413 of the method 400 above, and thus will not be repeated here for brevity.

[0490] In step 708, the first access network device determines that the frequency range currently operated by the terminal device is different from the target frequency range, and sends the indication information used to indicate the processing of the handover procedure to the AMF.

[0491] The frequency range in which the terminal device currently operates refers to the frequency range corresponding to the first wireless resource of the cell #1 in which the terminal device currently locates, i.e., the frequency range supported by the cell #1. If the frequency range in which the terminal device currently operates is inconsistent with the target frequency range, it can be determined that the terminal device needs to perform cell switching. Therefore, the first access network device can suspend the allocation of the DRB for the first session, and send the indication information indicating the processing of the switching procedure to the AMF. After receiving the indication information sent by the first access network device, the AMF can re-try to send the N2 interface request message in step 705 later, and continue to establish the user plane connection.

[0492] In step 709, the first access network device determines the target cell according to the target frequency range.

[0493] Optionally, step 709 specifically includes that the first access network device determines the target cell from the intra-station neighboring cells supporting the target frequency range.

[0494] Exemplarily, the first access network device can first determine whether there is a first cell supporting the target frequency range in the intra-station neighboring cells of the cell #1. In the case that there is the first cell, the first access network device can further determine whether the first cell supports the first network slice. In the case that the first cell supports the first network slice, the first access network device can determine whether the first cell can be the target cell according to the signal quality of the first cell. In the case that the signal quality of the first cell meets a second preset threshold, the first access network device determines that the first cell is the target cell. Thereafter, the intra-station switching procedure in step 714 can be performed.

[0495] Optionally, step 709 specifically includes that the first access network device determines the target cell from the inter-station neighboring cells supporting the target frequency range.

[0496] In the case that there is no first cell supporting the first cell in the intra-station neighboring cells of the cell #1, or in the case that the first cell does not support the first network slice, or in the case that the signal quality of the first cell is lower than the second preset threshold, or in the case that the cells served by the first access network device only include the cell #1, the first access network device can determine that there is no cell that can be the target cell in the intra-station neighboring cells. The first access network device can accordingly determine the target cell in the inter-station neighboring cells.

[0497] The specific process in which the first access network device determines the target cell in the inter-station neighboring cells has been described in detail in step 411 of the method 400 above, and will not be repeated here for brevity.

[0498] It should be understood that the related content of the target cell determined by the first access network device for the terminal device in the presence of multiple established sessions has been described in detail in the above method 400 and method 500, and for the sake of brevity, will not be repeated here.

[0499] It should also be understood that the related content of the target cell determined by the first access network device for the terminal device in the presence of one or more established sessions (for example, including active and / or deactivated sessions) has also been described in detail in the above method 400 and method 500, and for the sake of brevity, will not be repeated here.

[0500] In step 710, the first access network device controls the terminal device to switch to the target cell.

[0501] As mentioned earlier, the first access network device can control the terminal device to perform an intra-site handover procedure, or can control the terminal device to perform a cross-site handover procedure, depending on whether the target cell is a cell served by the first access network device. It should be understood that since the intra-site handover procedure and the cross-site handover procedure have been described in detail in step 305 in the above method 300, and the specific procedures of the terminal device for intra-site handover and cross-site handover can refer to the prior art, for the sake of brevity, will not be described in detail here.

[0502] In step 711, the AMF performs path switching to switch the terminal device to the second access network device.

[0503] In an implementation manner, the second access network device can send a handover complete message to the AMF based on the completion of the air interface handover with the terminal device, or send a path switching message to the AMF. The AMF can perform path switching based on the message from the second access network device.

[0504] In step 712, the AMF re-sends the N2 interface request message in step to the second access network device to continue establishing a user plane connection for the newly created first session.

[0505] In step 713, the second access network device allocates a DRB for the newly created first session in the frequency range supported by the target cell.

[0506] The frequency range supported by the target cell is the target frequency range described above. The second access network device can allocate a DRB for the first session in the target frequency range. And can send a session establishment accept message to the terminal device.

[0507] In a possible design, the session establishment accept message can be carried in an AN-specific resource setup message.

[0508] After the first session is successfully established, the terminal device can transmit service data through the first session.

[0509] It should be understood that the multiple steps shown above do not necessarily have to be performed. For example, if the target cell is an intra-site neighboring cell of the cell #1, part of the steps in the step 710 (steps related to the cross-site handover procedure) and the steps 711 to 713 do not necessarily have to be performed.

[0510] Based on the above technical solution, when the first session requested by the terminal device to be established in the source cell cannot be supported by the wireless resources of the source cell, the first access network device serving the source cell can determine a target cell for the terminal device according to the first network slice corresponding to the first session, the network slices supported by the at least one neighboring cell respectively, and the wireless resources corresponding to each network slice, and control the terminal device to hand over to the target cell. Therefore, the terminal device can timely hand over to the target cell in the case that the first session requested to be established cannot be supported by the wireless resources of the source cell and there is a target cell that can be handed over to, so that the first session can be successfully established, the session request of the terminal device can be responded to in a timely manner, and the user experience can be improved.

[0511] Figure 8 is still another illustrative flowchart of a communication method provided by an embodiment of the present application. Figure 8 The method 800 shown can include the steps 810 to 820.

[0512] In the step 810, the first access network device determines that the first wireless resource accessed by the terminal device in the source cell does not support the first network slice corresponding to the first session requested by the terminal device to be established or activated.

[0513] In the step 820, the first access network device sends an RRC connection release message to the terminal device to release the RRC connection with the terminal device.

[0514] In the step 810, the terminal device requests to establish or activate a session in the source cell, which is referred to as the first session, and the network slice corresponding to the first session is referred to as the first network slice. The first wireless resource accessed by the terminal device in the source cell does not support the first network slice corresponding to the first session, which can specifically mean that the frequency range provided by the first wireless resource does not support the first network slice, or in other words, the source cell does not support the first network slice. Therefore, the frequency range provided by the source cell cannot provide access services for the first network slice corresponding to the first session requested by the terminal device to be established or activated.

[0515] A possible scenario is that the terminal device accesses the network after powering on, or initiates a registration request to the network because it moves to a new TA not belonging to the original registration area. Alternatively, the terminal device initiates a registration request to the network when it periodically updates the registration to the network. The terminal device can carry a list of sessions that the terminal device requests to establish or activate in the registration request. The list includes the identification information of the sessions that the terminal device requests to establish and / or activate. The sessions that the terminal device requests to establish or activate may, for example, include but are not limited to the first session.

[0516] Another possible scenario is that the terminal device intends to establish a new session. The terminal device can send a session establishment request message to the first access network device to request to establish one or more sessions. The one or more sessions that the terminal device requests to establish may, for example, include but are not limited to the first session.

[0517] In the above-mentioned multiple possible scenarios, if the first access network device determines that the first wireless resource does not support the first network slice corresponding to the first session that the terminal device requests to establish or activate, it can be determined that the terminal device is not suitable to continue camping in the cell #1, and therefore step 220 can be performed to release the RRC connection with the terminal device.

[0518] Based on the RRC connection release between the terminal device and the first access network device, the terminal device enters the idle state and can then perform cell selection again to select a suitable cell and initiate an RRC connection request.

[0519] Based on the above technical solution, the first access network device can actively release the RRC connection with the terminal device in the case where the first wireless resource accessed by the terminal device does not support the first network slice of the first session that the terminal device requests to establish or activate, so that the terminal device can quickly enter the idle state and initiate cell reselection without having to wait until the current service is completed. Therefore, the terminal device can timely perform cell reselection in the case where the first session that the terminal device requests to establish or activate is not supported by the wireless resource of the source cell, so that the first session that the terminal device requests to establish or activate can be successfully activated, thereby enabling the terminal device to respond to the request in a timely manner and improving user experience.

[0520] Since the following Figure 9 and Figure 10 will be described in detail below in conjunction with the specific process of applying the communication method 800 provided by the present application to the above-mentioned scenarios, for brevity, no detailed description is given here.

[0521] Figure 9 is another exemplary flowchart of the communication method provided by the embodiments of the present application. Figure 9 The method 900 shown can include steps 901 to 921.

[0522] The flow to which the method 900 is applied is the same as the scenario to which the method 400 in the foregoing is applied, and thus details are not repeated herein for brevity.

[0523] In the method 900, the step 907 can correspond to the step 810 in the method 800, and the step 911 can correspond to the step 820 in the method 800. Alternatively, the RRC connection release message sent by the first access network device to the terminal device in the step 911 can carry the radio parameters for cell reselection. Alternatively, before the step 911, the method further includes: a step 910, determining, by the first access network device, the radio parameters according to the target frequency range, the network slices respectively supported by the at least one neighboring cell, and the frequency ranges corresponding to the network slices.

[0524] It should be understood that the related description about establishing a session and activating a session in each step in the method 900 can refer to the related description in the foregoing embodiments, and thus details are not repeated herein for brevity.

[0525] In the step 901, the terminal device sends, to the AMF via the first access network device, identification information for requesting to establish or to activate a first session.

[0526] In the step 902, the AMF obtains, from the UDM, identification information of network slices of subscription information of the terminal device.

[0527] In the step 903, the AMF determines the network slices allowed to be accessed by the terminal device.

[0528] In the step 904, the AMF determines the session allowed to be established or activated according to the network slices allowed to be accessed by the terminal device.

[0529] In the step 905, the SMF establishes an N4 interface session to control the UPF to establish a user plane connection of the first session, or the SMF modifies the N4 interface session to control the UPF to activate the user plane connection of the first session.

[0530] In the step 906, the AMF sends, to the first access network device, identification information of the network slices allowed to be accessed by the terminal device.

[0531] In the step 907, the first access network device determines that the first radio resource of the cell #1 in which the terminal device currently locates does not support a first network slice corresponding to the first session.

[0532] In the step 908, the first access network device determines a target frequency range according to the network slices allowed to be accessed by the terminal device, the first network slice, and a frequency range corresponding to the first network slice.

[0533] Alternatively, step 908 can also be implemented by the following steps: the first access network device can determine the target frequency range according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, and the network slice supported by the tracking area or the registration area where the terminal device is located, the first network slice, and the frequency range corresponding to the first network slice.

[0534] It should be understood that the specific processes of steps 901 to 908 can refer to the related description of steps 403 to 410 in method 400 above, and will not be repeated here for brevity.

[0535] In step 909, the first access network device determines that the frequency range in which the terminal device currently operates is different from the target frequency range.

[0536] The frequency range in which the terminal device currently operates is the frequency range supported by the cell #1 in which the terminal device currently operates, or the frequency range corresponding to the first wireless resource of the cell #1. If the frequency range in which the terminal device currently operates is different from the target frequency range, it means that the first wireless resource of the cell #1 does not support the first network slice.

[0537] In step 910, the first access network device determines the radio parameter according to the target frequency range, the network slice of at least one neighboring cell, and the frequency range corresponding to each network slice.

[0538] The radio parameter can be used for cell reselection of the terminal device. For example, the radio parameter can include an indication of the target frequency range, and the terminal device can preferentially reselect a cell supporting the target frequency range based on the indication.

[0539] In step 911, the first access network device sends an RRC connection release message to the terminal device to release the RRC connection with the terminal device.

[0540] Based on the fact that the cell #1 does not support the first network slice, the first access network device decides to suspend the allocation of DRB for the first session requested to be established or activated by the terminal device, and decides to release the RRC connection between the terminal device and the first access network device, and to deactivate all the established sessions of the terminal device. The terminal device thus directly enters the idle state for cell reselection without having to wait until the current service is completed before entering the idle state.

[0541] In one implementation, the radio parameter determined by the first access network device in step 910 can be carried in the above-mentioned RRC connection release message. That is, step 910 can be performed before step 911. In another implementation, the radio parameter can be delivered to the terminal device through other signaling. In this case, the order in which steps 910 and 911 are performed is not limited.

[0542] In a possible design, the identification information of the first session that the terminal device requests to establish or activate in step 901 can be carried in a registration request message sent by the terminal device to the AMF. The identification information of the network slice that the terminal device is allowed to access in step 906 can be carried in a registration accept message sent by the AMF to the first access network device. The RRC connection release message in step 910 can be carried in a registration accept message forwarded by the first access network device to the terminal device.

[0543] In step 912, the terminal device deactivates all sessions and enters the idle state.

[0544] The terminal device can enter the idle state based on the RRC connection release message received in step 911.

[0545] In step 913, the terminal device performs cell reselection based on the radio parameters to determine that the access network device to which the terminal device reaccesses is the second access network device.

[0546] The terminal device in the idle state can perform cell reselection based on the radio parameters sent down by the first access network device. The terminal device can first search for a suitable cell in a target frequency range based on the radio parameters, which can be understood as a target cell in the above embodiments, that is, the cell can provide access services of the first network slice in the target frequency range, or in other words, the radio resources provided by the cell support the first network slice. The terminal device can determine the access network device to which the terminal device reaccesses based on the access network device to which the cell belongs.

[0547] It is assumed that the terminal device determines that the access network device to which the terminal device reaccesses is the second access network device based on cell reselection.

[0548] In step 914, the terminal device initiates an RRC connection to the second access network device and sends a message that requests to establish or activate the first session, which carries the identification information of the first session that the terminal device requests to establish or activate.

[0549] In a possible design, the identification information of the first session that the terminal device requests to establish or activate can be carried in a service request message. The terminal device can send an RRC connection request message to the second access network device and carry the service request message in the RRC connection request message to request to establish or activate the first session.

[0550] In step 915, the second access network device sends a message that requests to establish or activate the first session to the AMF, which carries the identification information of the first session.

[0551] The second access network device in step 915 can forward the message of the above-mentioned request establishment or request activation to the AMF through an N2 interface message. As a response to the service request message received in step 914, the second access network device can forward the service request message to the AMF.

[0552] In step 916, the AMF sends a create session management context request message to the SMF, or the AMF sends a session management context update request message to the SMF.

[0553] In step 917, the SMF accepts the request of the first session establishment, or the SMF accepts the request of the user plane activation. The SMF can also reselect a new UPF due to the terminal device accessing the new access network device.

[0554] In step 918, the SMF establishes an N4 interface session to control the UPF to establish the user plane connection of the first session, or the SMF modifies the N4 interface session to control the UPF to activate the user plane connection of the first session.

[0555] In step 919, the SMF sends a create session management context success response message to the AMF, or the SMF sends a session management context update success response message to the AMF.

[0556] In step 920, the AMF sends an N2 interface request message to the second access network device, where the information of the first session is carried, where the identification information of the first network slice corresponding to the first session is included.

[0557] In step 921, the second access network device establishes a DRB for the terminal device at a target frequency range according to the first network slice corresponding to the first session, and connects the user plane of the first session.

[0558] Thus, the first session is successfully activated. The terminal device can transmit service data through the first session.

[0559] Based on the above technical solution, when the first session requested to be established or activated by the terminal device in the source cell cannot be supported by the wireless resources of the source cell, the first access network device serving the source cell can directly release the RRC connection with the terminal device, so that the terminal device enters the idle state and performs cell reselection without waiting until the current service of the terminal device is completed. Therefore, the terminal device can timely perform cell reselection in the case that the first session requested to be established or activated cannot be supported by the wireless resources of the source cell, so that the first session requested to be established or activated by the terminal device can be successfully activated, thereby the terminal device can timely respond to the request, which is beneficial to improve the user experience.

[0560] Figure 10is another illustrative flowchart of a communication method provided by an embodiment of the present application. Figure 10 The method 1000 shown can include steps 1001 to 1020.

[0561] The flow to which the method 1000 applies is the same as the scenario to which the method 600 applies above, and for brevity, will not be repeated here.

[0562] In the method 1000, the step 1006 can correspond to the step 810 in the method 800, and the step 1010 can correspond to the step 820 in the method 800. Optionally, the RRC connection release message sent by the first access network device to the terminal device in the step 1010 can carry the radio parameters for cell reselection. Optionally, before the step 1010, the method further includes: a step 1009, the first access network device determines the radio parameters according to the target frequency range, the network slices respectively supported by the at least one neighboring cell, and the frequency ranges corresponding to the network slices.

[0563] It should be understood that the related description in the steps in the method 1000 about establishing a session and activating a session can refer to the related description in the embodiments above, and for brevity, will not be repeated here.

[0564] In the step 1001, the terminal device sends a message to the AMF via the first access network device to request to establish or activate a first session, the message carrying identification information of the first session.

[0565] In the step 1002, the AMF and the SMF create a session management context for the first session requested to be established, or update the session management context.

[0566] In the step 1003, the SMF and the UPF establish or modify an N4 interface session.

[0567] In the step 1004, the SMF sends identification information of a first network slice to the AMF.

[0568] In the step 1005, the AMF sends the identification information of the first network slice to the first access network device.

[0569] In the step 1006, the first access network device determines that the first radio resource of a cell #1 in which the terminal device is currently located does not support a first network slice corresponding to a first session.

[0570] In the step 1007, the first access network device determines a target frequency range according to the network slices allowed to be accessed by the terminal device, the first network slice, and the operating frequency corresponding to the first network slice.

[0571] Alternatively, step 1007 can also be implemented by the following steps: the first access network device can determine the target frequency range according to the network slice requested by the terminal device, the network slice that the terminal device can use according to the subscription, and the network slice supported by the tracking area or the registration area where the terminal device is located, the first network slice, and the frequency range corresponding to the first network slice.

[0572] It should be understood that the specific processes of steps 1001 to 1007 can refer to the related description of steps 701 to 707 in method 700 above, and will not be repeated here for brevity.

[0573] In step 1008, the first access network device determines that the frequency range in which the terminal device currently operates is different from the target frequency range.

[0574] In step 1009, the first access network device determines the radio parameters according to the network slice of at least one neighboring cell of the first frequency and the frequency range corresponding to each network slice.

[0575] In step 1010, the first access network device sends an RRC connection release message to the terminal device to release the RRC connection with the terminal device.

[0576] In step 1011, the terminal device deactivates all sessions and enters an idle state.

[0577] In step 1012, the terminal device performs cell reselection based on the radio parameters to determine that the access network device re-accessed is the second access network device.

[0578] In step 1013, the terminal device initiates an RRC connection to the second access network device and sends identification information of the first session requested to be established.

[0579] In step 1014, the second access network device sends the identification information of the first session to the AMF.

[0580] In step 1015, the AMF sends a create session management context request message to the SMF, or the AMF sends a session management context update request message to the SMF.

[0581] In step 1016, the SMF accepts the request for establishing the first session, or the SMF accepts the request for activating the user plane. The SMF can also select a new UPF due to the terminal device accessing the new access network device.

[0582] In step 1017, the SMF establishes an N4 interface session to control the UPF to establish the user plane connection of the first session, or the SMF modifies the N4 interface session to control the UPF to activate the user plane connection of the first session.

[0583] At step 1018, the SMF sends a response message of the creation session management context success to the AMF, or the SMF sends a response message of the session management context update success to the AMF.

[0584] At step 1019, the AMF sends an N2 interface request message to the second access network device, where the information of the first session is carried, where the identification information of the first network slice corresponding to the first session is included.

[0585] At step 1020, the second access network device establishes a DRB for the terminal device at a target frequency range according to the first network slice corresponding to the first session, and connects the user plane of the first session.

[0586] Thus, the first session is successfully established and activated. The terminal device can transmit service data through the first session.

[0587] It should be understood that the specific processes of steps 1008 to 1020 can refer to the related description of steps 909 to 921 in method 900 above, and will not be repeated here for brevity.

[0588] Based on the above technical solution, when the first session requested by the terminal device to be established or activated in the source cell cannot be supported by the wireless resources of the source cell, the first access network device serving the source cell can directly release the RRC connection between the terminal device, so that the terminal device enters the idle state and performs cell reselection without waiting until the current service of the terminal device is completed. Therefore, the terminal device can timely perform cell reselection in the case that the first session requested to be established or activated is not supported by the wireless resources of the source cell, so that the first session requested by the terminal device to be established can be successfully established and activated, thereby the terminal device can timely respond to the request, and the user experience is improved.

[0589] It should be understood that in the above embodiments, each network element can perform part or all of the steps in each embodiment. These steps or operations are only examples, and the embodiments of the present application can also perform other operations or variations of various operations. In addition, each step can be executed in a different order as presented in each embodiment, and it is possible that not all operations in the embodiments of the present application are executed. Moreover, the size of the serial number of each step does not mean the order of execution, the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0590] The above, in combination with Figures 2 to 10 The communication method provided by the embodiments of the present application is described in detail. Hereinafter, in combination with Figures 11 to 13 The communication device provided by the embodiments of the present application is described in detail.

[0591] Figure 11is a schematic block diagram of a communication apparatus provided by an embodiment of the present application. As shown in Figure 11 The communication apparatus 2000 can include a determining unit 2100, a control unit 2200, and a transceiver unit 2300.

[0592] Optionally, the communication apparatus 2000 can correspond to the first access network device in the above method embodiments, for example, can be the first access network device, or a component (such as a circuit, a chip, or a chip system, etc.) configured in the first access network device.

[0593] It should be understood that the communication apparatus 2000 can correspond to the first access network device in the methods 200 to 1000 according to the embodiments of the present application, and the communication apparatus 2000 can include units for performing the methods of the first access network device in the methods 200 to 1000. Figure 2 Figure 10 The units in the communication apparatus 2000 and the above other operations and / or functions are respectively used to implement the corresponding procedures of the methods 200 to 1000 in the methods 200 to 1000. Figure 2 Figure 10 The units in the communication apparatus 2000 and the above other operations and / or functions are respectively used to implement the corresponding procedures of the methods 200 to 1000 in the methods 200 to 1000.

[0594] It should be understood that when the communication apparatus 2000 is the first access network device, the transceiver unit 2300 in the communication apparatus 2000 can be implemented by a transceiver, for example, can correspond to the transceiver 3020 in the communication apparatus 3000 shown in Figure 12 or the RRU 4100 in the base station 4000 shown in Figure 13 The determining unit 2100 and the control unit 2200 in the communication apparatus 2000 can be implemented by at least one processor, for example, can correspond to the processor 3010 in the communication apparatus 3000 shown in Figure 12 or the processing unit 4200 or the processor 4202 in the base station 4000 shown in Figure 13

[0595] It should also be understood that when the communication apparatus 2000 is a chip or a chip system configured in the first access network device, the transceiver unit 2300 in the communication apparatus 2000 can be implemented by an input / output interface, a circuit, etc., and the determining unit 2100 and the control unit 2200 in the communication apparatus 2000 can be implemented by a processor, a microprocessor, or an integrated circuit, etc. integrated on the chip or the chip system.

[0596] Figure 12 is another schematic block diagram of a communication apparatus 3000 provided by an embodiment of the present application. As shown in Figure 12 ​​​As shown, the communication apparatus 3000 includes a processor 3010, a transceiver 3020 and a memory 3030. The processor 3010, the transceiver 3020 and the memory 3030 communicate with each other by an internal connection path. The memory 3030 is configured to store instructions. The processor 3010 is configured to execute the instructions stored in the memory 3030 to control the transceiver 3020 to transmit and / or receive signals.

[0597] It should be understood that the communication apparatus 3000 can correspond to the first access network device in the above-mentioned method embodiments, and can be used to execute the steps and / or procedures executed by the first access network device in the above-mentioned method embodiments. Optionally, the memory 3030 can include a read-only memory and a random access memory, and provide instructions and data for the processor. A part of the memory can also include a non-volatile random access memory. The memory 3030 can be a separate device, or integrated in the processor 3010. The processor 3010 can be configured to execute the instructions stored in the memory 3030, and when the processor 3010 executes the instructions stored in the memory, the processor 3010 is configured to execute the steps and / or procedures corresponding to the first access network device in the above-mentioned method embodiments.

[0598] Optionally, the communication apparatus 3000 is the first access network device in the above-mentioned embodiments.

[0599] Optionally, the transceiver 3020 can include a transmitter and a receiver. The transceiver 3020 can further include an antenna, and the number of the antennas can be one or more. The processor 3010 and the memory 3030 and the transceiver 3020 can be devices integrated on different chips. For example, the processor 3010 and the memory 3030 can be integrated in a baseband chip, and the transceiver 3020 can be integrated in a radio frequency chip. The processor 3010 and the memory 3030 and the transceiver 3020 can also be devices integrated on the same chip. The present application does not make any limitation in this regard.

[0600] Optionally, the communication apparatus 3000 is a component, such as a circuit, a chip, a chip system, etc., configured in the first access network device.

[0601] Optionally, the transceiver 3020 can also be a communication interface, such as an input / output interface, a circuit, etc. The transceiver 3020, the processor 3010 and the memory 3030 can be integrated in the same chip, such as a baseband chip.

[0602] Figure 13 FIG. 4 is a structural schematic diagram of a network device provided by the embodiments of the present application, for example, a structural schematic diagram of a base station. The base station 4000 can be applied to, for example, the network device in the above-mentioned method embodiments. Figure 1In the illustrated system, the functions of the first access network device in the above method embodiments are performed.

[0603] As shown, the base station 4000 can include one or more remote radio units (RRUs) 4100 and one or more baseband units (BBUs) (also referred to as distributed units (DUs)) 4200. The RRU 4100 can be referred to as a transceiver unit, which can be in communication with Figure 11 the transceiver 3020 in the base station 3000 in Figure 12 . Optionally, the RRU 4100 can also be referred to as a transceiver, transceiver circuit, or transceiver, etc., which can include at least one antenna 4101 and a radio frequency unit 4102. Optionally, the RRU 4100 can include a receiving unit, which can correspond to a receiver (or receiver, receiver circuit), and a transmitting unit, which can correspond to a transmitter (or transmitter, transmitter circuit). The RRU 4100 part is mainly used for the transceiving of radio frequency signals and the conversion between radio frequency signals and baseband signals, such as for sending wireless measurement parameters, RRC connection release messages, etc. to terminal devices. The BBU 4200 part is mainly used for baseband processing, controlling the base station, etc. The RRU 4100 and the BBU 4200 can be physically arranged together or physically separated, i.e., a distributed base station.

[0604] The BBU 4200 is the control center of the base station, which can also be referred to as a processing unit, which can correspond to the determination unit 2100 and the control unit 2200 in the base station 2000 in Figure 11 or the processor 3010 in the base station 3000 in Figure 12 , and is mainly used to complete baseband processing functions such as channel coding, multiplexing, modulation, spreading, etc. For example, the BBU (processing unit) can be used to control the base station to perform the operation processes of the first access network device in the above method embodiments, such as determining a target frequency range, determining a target cell, etc.

[0605] In an example, the BBU 4200 can be composed of one or more boards, and the boards can collectively support a wireless access network of a single access technology (e.g., an LTE network), or can separately support wireless access networks of different access technologies (e.g., an LTE network, a 5G network, or other networks). The BBU 4200 further includes a memory 4201 and a processor 4202. The memory 4201 is configured to store necessary instructions and data. The processor 4202 is configured to control the base station to perform necessary actions, e.g., to control the base station to perform the operations of the network device in the above method embodiments. The memory 4201 and the processor 4202 can serve one or more boards. That is, the memory and the processor can be separately arranged on each board. Alternatively, the memory and the processor can be shared by multiple boards. In addition, necessary circuits can be further arranged on each board.

[0606] It should be understood that, Figure 13 The base station 4000 shown can implement the above method embodiments. Figures 2 to 10 The above method embodiments involve various processes of the first access network device. The operations and / or functions of various modules in the base station 4000 are respectively configured to implement the corresponding processes in the above method embodiments. For details, refer to the descriptions in the above method embodiments, and the detailed descriptions are appropriately omitted here.

[0607] The above BBU 4200 can be configured to perform the actions implemented internally by the first access network device in the above method embodiments, and the RRU 4100 can be configured to perform the actions of sending or receiving, by the first access network device, to or from the terminal device in the above method embodiments. For details, refer to the descriptions in the above method embodiments, and the detailed descriptions are appropriately omitted here.

[0608] It should be understood that, Figure 13 The base station 4000 shown is only one possible form of the access network device, and should not constitute any limitation on the present application. The methods provided by the present application can be applied to other forms of access network devices. For example, the access network device can include an AAU, and can further include a CU and / or a DU, or can include a BBU and an adaptive radio unit (ARU), or a BBU; the access network device can also be a customer premises equipment (CPE), and can also be in other forms, and the present application does not limit the specific form of the network device.

[0609] The CU and / or the DU can be configured to perform the actions implemented internally by the access network device in the above method embodiments, and the AAU can be configured to perform the actions of sending or receiving, by the access network device, to or from the terminal device in the above method embodiments. For details, refer to the descriptions in the above method embodiments, and the detailed descriptions are appropriately omitted here.

[0610] The application further provides a processing apparatus, comprising at least one processor, wherein the at least one processor is configured to execute a computer program stored in a memory, so that the processing apparatus performs the method performed by the first access network device in any of the above method embodiments.

[0611] The application further provides a processing apparatus, comprising a processor and a communication interface, wherein the communication interface is coupled to the processor, and the communication interface is configured to input and / or output information, and the information comprises at least one of instructions and data, and the processor is configured to execute a computer program, so that the processing apparatus performs the method performed by the first access network device in any of the above method embodiments.

[0612] The application further provides a processing apparatus, comprising a processor and a memory, wherein the memory is configured to store a computer program, and the processor is configured to call and run the computer program from the memory, so that the processing apparatus performs the method performed by the first access network device in any of the above method embodiments.

[0613] It should be understood that the above processing apparatus can be one or more chips. For example, the processing apparatus can be a field programmable gate array (FPGA), can be an application specific integrated circuit (ASIC), can be a system on chip (SoC), can be a central processor unit (CPU), can be a network processor (NP), can be a digital signal processor (DSP), can be a micro controller unit (MCU), can be a programmable logic device (PLD) or other integrated chip.

[0614] In the implementation process, the steps of the above method can be completed by the integrated logic circuit of hardware in the processor or the instruction in the form of software. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as hardware processor execution completion, or executed by the combination of hardware and software modules in the processor. The software module can be located in the mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, register, etc. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0615] It should be noted that the processor in the embodiments of the present application can be an integrated circuit chip with signal processing capability. In the implementation process, the steps of the above method embodiments can be completed by the integrated logic circuit of hardware in the processor or the instruction in the form of software. The above processor can be a general processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. The disclosed methods, steps and logic block diagrams in the embodiments of the present application can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as hardware decoding processor execution completion, or executed by the combination of hardware and software modules in the decoding processor. The software module can be located in the mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, register, etc. The storage medium is located in the memory, and the processor reads the information in the memory, and combines the hardware to complete the steps of the above method.

[0616] It is to be appreciated that the memory in the embodiments of the application can be a volatile or non-volatile memory, or can include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as external cache. By way of example, and not limitation, many forms of RAM are available, for example, static RAM (SRAM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct RAM bus RAM (DRAM). It is to be appreciated that the memory described herein is intended to include, without being limited to, these and any other suitable types of memory.

[0617] According to the method provided in the embodiments of the application, the application further provides a computer program product, which comprises computer program codes, and when the computer program codes run on a computer, the computer is caused to execute the method performed by the first access network device in the embodiments shown. Figures 2 to 10 The method performed by the first access network device in the embodiments shown.

[0618] According to the method provided in the embodiments of the application, the application further provides a computer readable storage medium, which stores program codes, and when the program codes run on a computer, the computer is caused to execute the method performed by the first access network device in the embodiments shown. Figures 2 to 10 The method performed by the first access network device in the embodiments shown.

[0619] According to the method provided in the embodiments of the application, the application further provides a communication system, which comprises one or more first access network devices and one or more terminal devices described above. Optionally, the communication system further comprises one or more second access network devices described above.

[0620] The communication device in each of the above device embodiments or the base station and the first access network device in the method embodiment fully correspond, and the corresponding steps are performed by the corresponding modules or units, for example, the transceiving unit (transceiver) performs the steps of receiving or transmitting in the method embodiment, and other steps except for transmitting and receiving can be performed by the processing unit (processor). The functions of the specific units can be referred to the corresponding method embodiments. The processor can be one or more.

[0621] The terms "component," "module," "system," and the like as used herein are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and / or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and / or thread of execution and a component can be localized, co-resident, and / or distributed amongst one computer and / or across two or more computers. Also, these components can execute from various computer readable media having various data structures stored thereon. The components can communicate by way of local and / or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and / or across a network such as the Internet with other systems via the signal).

[0622] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0623] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0624] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic. The division of the units is merely logical function division. There can be other division manners in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0625] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0626] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can be a physically separate unit, or two or more units can be integrated into one unit.

[0627] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of a software product, and the computer software product is stored in a storage medium, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0628] The above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: The method comprises: A first access network device determines that a signal quality of a terminal device in a source cell is lower than a preset threshold, the source cell being a cell served by the first access network device; The first access network device determines a radio measurement parameter according to a first network slice corresponding to a first session activated by the terminal device in the source cell, network slices supported by at least one neighboring cell of the source cell, and radio resources corresponding to the supported network slices, the radio measurement parameter being used for signal quality measurement of the terminal device on the neighboring cells; A target cell is determined from the at least one neighboring cell according to the signal quality measurement, wherein the target cell supports the first network slice, and the target cell is a cell served by a second access network device; The first access network device controls the terminal device to switch to the target cell.

2. The method of claim 1, wherein, The method further comprises: The first access network device sends the radio measurement parameter to the terminal device, the radio measurement parameter being used for signal quality measurement of the terminal device on the neighboring cells, the radio measurement parameter being determined based on a target frequency range, the target frequency range being determined according to the first network slice, network slices supported by the at least one neighboring cell, and frequency ranges corresponding to the first network slice in each cell, the target frequency range having a priority higher than a second frequency range, the first frequency range being the same as a frequency range corresponding to the first network slice, and the second frequency range being different from the frequency range corresponding to the first network slice; wherein the signal quality measurement of the terminal device on the neighboring cells is used for determination of the target cell.

3. The method of claim 1 or 2, wherein, The method further comprises: The first access network device sends a request message to the second access network device, the request message carrying identification information of the first session and identification information of the first network slice; The first access network device receives a radio resource control (RRC) parameter for switching from the second access network device; The first access network device sends the RRC parameter to the terminal device.

4. The method of claim 3, wherein, The RRC parameter is associated with the first network slice, network slices supported by the second access network device, and radio resources corresponding to the network slices supported by the second access network device.

5. A communication device, characterized by The method comprises: A determining unit is configured to determine that a signal quality of a terminal device in a source cell is lower than a preset threshold, the source cell being a cell served by the apparatus; The apparatus is further configured to determine a radio measurement parameter according to a first network slice corresponding to a first session activated by the terminal device in the source cell, network slices supported by at least one neighboring cell of the source cell, and radio resources corresponding to the supported network slices, the radio measurement parameter being used for signal quality measurement of the terminal device on the neighboring cells, and to determine a target cell from the at least one neighboring cell according to the signal quality measurement, wherein the target cell supports the first network slice, and the target cell is a cell served by a second access network device. A control unit is configured to control the terminal device to switch to the target cell. 6.The apparatus of claim 5, wherein, The apparatus further includes a transceiver configured to send the wireless measurement parameter to the terminal device, the wireless measurement parameter being used for the terminal device to measure the signal quality of the neighboring cells, the wireless measurement parameter being determined based on a target frequency range, the target frequency range being determined according to the first network slice, network slices supported by the at least one neighboring cell respectively, and frequency ranges corresponding to the first network slice in each cell, the target frequency range being a first frequency range having a higher priority than a second frequency range, the first frequency range being the same as a frequency range corresponding to the first network slice, and the second frequency range being different from the frequency range corresponding to the first network slice, wherein the measurement of the signal quality of the neighboring cells by the terminal device is used for the determination of the target cell.

7. The apparatus of claim 5 or 6, wherein, The apparatus further includes a transceiver configured to: send, to the second access network device, a request message carrying identification information of the first session and identification information of the first network slice; receive, from the second access network device, a radio resource control (RRC) parameter for switching; send, to the terminal device, the RRC parameter.

8. The apparatus of claim 7, wherein, The RRC parameter is associated with the first network slice, network slices supported by the second access network device, and wireless resources corresponding to the network slices supported by the second access network device.

9. A computer-readable storage medium, characterized in that, A computer program product including a computer program that, when executed on a computer, causes the computer to perform the method of any one of claims 1 to 4.

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