A communication method, a communication device and a communication system

Abstract

The present application provides a communication method, a communication device and a communication system, the method comprising: a terminal device residing in a first network in a radio resource control RRC idle state or an RRC deactivated state determines that it needs to enter a second network through network selection; the terminal device enters an RRC connected state; the terminal device initiates a deregistration process to the first network. According to the communication method provided by the present application, before leaving the first network, the terminal device in the RRC idle state or the RRC deactivated state will first enter the RRC connected state, and deregister in the first network through the deregistration process, informing the first network that it is about to leave. Through the above settings, invalid paging of the terminal device by the first network can be avoided, saving air interface resources and power of access network equipment.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a communication method, a communication device and a communication system. Background Art

[0002] In recent years, in order to meet the usage needs of different users, terminal devices that support access to multiple different networks have emerged. For example, for a certain terminal device, it can not only access the public land mobile network (PLMN), but also access the stand-alone non-public network (SNPN). At this time, a switch for the stand-alone non-public network access mode (SNPN access mode) can be set on the terminal device (for example, it can be similar to a WIFI switch), and the user can choose whether to turn on the stand-alone non-public network access mode by turning the switch on or off, and then choose which network to enter. For example, when the user turns on the switch, the user can only choose to access the stand-alone private network, but cannot choose to access the public network. Correspondingly, when the user turns off the switch, the user can only choose to access the public network, but cannot choose to access the stand-alone non-public network.

[0003] On this basis, once the state of the independent private network access mode changes, whether it is turned on or off, the terminal device will re-select the network between the public network and the independent private network. When selecting the target network, if the terminal device is in an idle or deactivated state in the original network, the terminal device will directly leave the original network and enter the target network.

[0004] In this way, the original network side does not know that the terminal device has left. From the original network's point of view, the terminal device is still an idle terminal device in the original network. At this time, if the original network side has data to send to the terminal device, it will use paging messages to find the terminal device, but because the terminal device has gone to other networks and cannot receive paging messages, the base station on the original network side will continue to page the terminal device, resulting in a large waste of air interface resources and the power of the base station. Summary of the invention

[0005] The present application provides a communication method, a communication device and a communication system, which can avoid invalid paging on the original network side and save air interface resources and power of access network equipment.

[0006] In a first aspect, a communication method is provided. The method may be executed by a terminal device, or may be executed by a chip or circuit configured in the terminal device, and the present application does not limit this.

[0007] Specifically, the method includes: a terminal device residing in a first network in a radio resource control RRC idle state or an RRC deactivated state determines that it needs to enter a second network through network selection; the terminal device enters an RRC connected state; and the terminal device initiates a deregistration process to the first network.

[0008] The terminal device of the present application can access the first network and can also access the second network, that is, the terminal device of the present application has the ability to access multiple different networks and can make a network selection between the first network and the second network.

[0009] When the terminal device determines that it needs to leave the first network and enter the second network through the network, if the terminal device is currently residing in the first network in the RRC idle state or the RRC deactivated state, the terminal device will first enter the RRC connected state and initiate a deregistration process to the first network. It will leave the first network only after the deregistration process is completed.

[0010] In the embodiment of the present application, the terminal device initiates a deregistration process to the first network, which means that the terminal device deregisters in the first network so that it is in a deregistered state in the first network. After the deregistration process is completed, the context of the terminal device in the first network almost disappears (except for a small amount of information for facilitating authentication). The first network will know that the terminal device has left the network, and when the data of the terminal device arrives on the first network side, it will not page the terminal device. In some cases, the deregistration of the present application can also be understood as deattachment.

[0011] According to an embodiment of the present application, a terminal device in an RRC idle state or an RRC deactivated state will first enter an RRC connected state before leaving the first network, and deregister in the first network through a deregistration process, informing the first network that it is about to leave. Through the above settings, invalid paging of the terminal device by the first network can be avoided, saving air interface resources and power of access network equipment.

[0012] Optionally, in addition to being able to access the first network and the second network, the terminal device may also have the ability to access other networks, which is not limited in this application.

[0013] Optionally, the first network may be a public network, and the second network may be an independent private network. The terminal device may determine that it needs to enter the second network through network selection according to a change in the independent private network access mode state.

[0014] Optionally, the network selection may be an automatic network selection or a manual network selection by a user, which is not limited in the present application.

[0015] In the embodiment of the present application, the first network and the second network are two different networks, and the types of the first network and the second network can be the same or different, and the present application does not limit this. For example, the first network can be any one of a public network, an independent private network, a non-independent private network, a non-terrestrial network, etc., and the second network can also be any one of a public network, an independent private network, a non-independent private network, a non-terrestrial network, etc.

[0016] The standards of the first network and the second network may be the same or different, and this application does not limit this.

[0017] Optionally, mobility may be supported between the first network and the second network. The following is an example to illustrate the support of mobility.

[0018] Optionally, supporting mobility between the first network and the second network may mean that the terminal device can perform cell switching and cell reselection between the first network and the second network.

[0019] Optionally, supporting mobility between the first network and the second network may mean that the first network and the second network share the same core network equipment (for example, share the same access and mobility management function (AMF) entity, and AMF is used as an example below for explanation).

[0020] Optionally, supporting mobility between the first network and the second network may mean that control plane signaling can be interacted between the AMFs of the first network and the second network.

[0021] For example, the first network may be a public network, and the second network may be a non-independent private network that depends on the public network. Alternatively, the first network may be a non-independent private network, and the second network may be a public network that the non-independent private network depends on.

[0022] For another example, the first network and the second network may be two non-independent private networks that rely on the same public network.

[0023] In the embodiment of the present application, optionally, mobility may not be supported between the first network and the second network. The following is an example of not supporting mobility.

[0024] Optionally, mobility is not supported between the first network and the second network, which may mean that the terminal device cannot perform cell switching and cell reselection between the first network and the second network.

[0025] Optionally, mobility is not supported between the first network and the second network, which may mean that the first network and the second network respectively use their own AMFs, and control plane signaling cannot be interacted between the AMFs.

[0026] For example, the first network may be an independent private network, and the second network may be any one of a public network, a non-independent private network, a non-terrestrial network, and other independent private networks.

[0027] For another example, the first network may be any one of a public network, a non-independent private network, a non-terrestrial network, and an independent private network, and the second network may be another independent private network.

[0028] Mobility is not supported between the first network and the second network, so that the core network device of the first network and the core network device of the second network cannot exchange the context information of the terminal device, that is, the core network device cannot actively initiate the deregistration process of the terminal device, which makes the method provided in the embodiment of the present application more meaningful.

[0029] In combination with the first aspect, in certain implementations of the first aspect, the terminal device enters the RRC connection state, including: the terminal device is connected to a first cell, the first cell is a cell of a first network in which the terminal device is currently located, or the first cell is other cells of the first network.

[0030] In a second aspect, a communication method is provided. The method may be executed by a terminal device, or may be executed by a chip or circuit configured in the terminal device, and the present application does not limit this.

[0031] Specifically, the method includes: a terminal device determines that a first user identity needs to be deregistered in a first network, and the terminal device supports the first user identity and the second user identity; the terminal device sends a deregistration request message to an access network device as the second user identity, the deregistration request message carries an identifier of the first user identity, and the deregistration request message is used to request the first user identity to be deregistered in the first network.

[0032] The communication method provided by the present application can send a deregistration request message for the first user identity to the access network device through the second user identity when the first user identity in the terminal device needs to be deregistered in the first network, so as to initiate the deregistration process of the first user identity to the first network, and inform the first network that the first user identity is about to leave. Through the above settings, invalid paging of the first user identity by the first network can be avoided, thereby saving air interface resources and power of the access network device.

[0033] Optionally, the first network may be any one of a public network, a non-independent private network, a non-terrestrial network, and an independent private network.

[0034] The access network device provides services for the second user identity, or in other words, the access network device is an access network device to which a service cell of the second user identity belongs.

[0035] Optionally, before the terminal device sends a deregistration request message to the access network device as a second user identity, the second user identity may be in an idle state, a deactivated state, or a connected state, which is not limited in this application.

[0036] For example, the second user identity may be in an idle state, and at this time the second user identity needs to establish an RRC connection with the access network device first.

[0037] For another example, the second user identity may be in a deactivated state, and at this time, the second user identity needs to restore the RRC connection with the access network device first.

[0038] In combination with the second aspect, in some implementations of the second aspect, the access network device belongs to the first network, or the access network device belongs to a third network, and mobility is supported between the third network and the first network.

[0039] Optionally, the access network device may belong to the first network, that is, the second user identity is a user in the first network. In other words, the first user identity and the second user identity may belong to users in the same network, for example, the first user identity and the second user identity belong to the same operator.

[0040] Optionally, the access network device may also belong to a third network, that is, the second user identity is a user in the third network. In other words, the first user identity and the second user identity may belong to users in different networks. In this case, mobility is supported between the third network and the first network, so that a deregistration process of the first user identity may be initiated to the first network through the third network. The following is an example of supporting mobility between the third network and the first network.

[0041] In conjunction with the second aspect, in some implementations of the second aspect, the deregistration request message also carries an identifier of the second user identity, and the deregistration request message is also used to request deregistration of the second user identity. Through the above settings, one deregistration request message can request deregistration of multiple user identities.

[0042] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: the terminal device receives a deregistration acceptance message sent by the access network device as the second user, and the deregistration acceptance message carries an identifier of the first user identity. Through the above settings, the terminal device can determine that the deregistration application for the first user is accepted by the network side.

[0043] In combination with the second aspect, in some implementations of the second aspect, the terminal device determines that the first user identity needs to be deregistered in the first network, including: the terminal device determines that the first user identity residing in the first network needs to enter the second network through network selection.

[0044] In a third aspect, a communication method is provided. The method may be executed by an access network device, or may be executed by a chip or circuit configured in the access network device, and the present application does not limit this.

[0045] Specifically, the method includes: an access network device receives a deregistration request message sent by a terminal device as a second user, the deregistration request message carries an identifier of a first user identity, and the deregistration request message is used to request the first user identity to deregister in the first network; the access network device sends a deregistration request message to a core network device.

[0046] In combination with the third aspect, in some implementations of the third aspect, the access network device belongs to the first network, or the access network device belongs to a third network, and mobility is supported between the third network and the first network.

[0047] In combination with the third aspect, in certain implementations of the third aspect, the deregistration request message further carries an identifier of the second user identity, and the deregistration request message is further used to request deregistration of the second user identity.

[0048] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: the access network device sends a deregistration acceptance message to the second user identity of the terminal device, and the deregistration acceptance message carries an identifier of the first user identity.

[0049] In a fourth aspect, a communication device is provided, comprising: a processing unit and a transceiver unit, the processing unit being used to determine that the communication device residing in the first network in a radio resource control RRC idle state or an RRC deactivated state needs to enter a second network through network selection; the processing unit is also used to control the communication device to enter an RRC connected state; the processing unit is also used to initiate a deregistration process to the first network through the transceiver unit.

[0050] In combination with the fourth aspect, in certain implementations of the fourth aspect, the processing unit is also used to control the communication device to connect to a first cell, where the first cell is a cell of a first network in which the communication device is currently located, or the first cell is other cells of the first network.

[0051] In a fifth aspect, a communication device is provided, comprising: a processing unit, used to determine that a first user identity needs to be deregistered in a first network, the communication device supports a first user identity and a second user identity; a transceiver unit, used to send a deregistration request message to an access network device as the second user identity, the deregistration request message carries an identifier of the first user identity, and the deregistration request message is used to request the first user identity to be deregistered in the first network.

[0052] In combination with the fifth aspect, in some implementations of the fifth aspect, the access network device belongs to the first network, or the access network device belongs to a third network, and mobility is supported between the third network and the first network.

[0053] In combination with the fifth aspect, in certain implementations of the fifth aspect, the deregistration request message further carries an identifier of the second user identity, and the deregistration request message is further used to request deregistration of the second user identity.

[0054] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is further used to receive a deregistration acceptance message sent by the access network device as the second user identity, and the deregistration acceptance message carries an identifier of the first user identity.

[0055] In combination with the fifth aspect, in some implementations of the fifth aspect, the processing unit is further used to determine that the first user identity residing in the first network needs to enter the second network through network selection.

[0056] In the sixth aspect, a communication device is provided, including: a receiving unit, used to receive a deregistration request message sent by a terminal device as a second user identity, the deregistration request message carries an identifier of a first user identity, and the deregistration request message is used to request the first user identity to deregister in the first network; a sending unit, used to send the deregistration request message to a core network device.

[0057] In combination with the sixth aspect, in some implementations of the sixth aspect, the communication device belongs to the first network, or the communication device belongs to a third network, and mobility is supported between the third network and the first network.

[0058] In combination with the sixth aspect, in certain implementations of the sixth aspect, the deregistration request message also carries an identifier of the second user identity, and the deregistration request message is also used to request deregistration of the second user identity.

[0059] In combination with the sixth aspect, in certain implementations of the sixth aspect, the sending unit is further used to send a deregistration acceptance message to the second user identity of the terminal device, and the deregistration acceptance message carries an identifier of the first user identity.

[0060] In the seventh aspect, a communication device is provided, which may be a terminal device or a chip in a terminal device. The device may include a processing unit and a transceiver unit. When the device is a terminal device, the processing unit may be a processor, and the transceiver unit may be a transceiver; the terminal device may also include a storage unit, and the storage unit may be a memory; the storage unit is used to store instructions, and the processing unit executes the instructions stored in the storage unit so that the terminal device executes the method in the first aspect or the second aspect. When the device is a chip in a terminal device, the processing unit may be a processor, and the transceiver unit may be an input / output interface, a pin or a circuit, etc.; the processing unit executes the instructions stored in the storage unit so that the terminal device executes the method in the first aspect or the second aspect, and the storage unit may be a storage unit in the chip (for example, a register, a cache, etc.), or a storage unit in the terminal device located outside the chip (for example, a read-only memory, a random access memory, etc.).

[0061] In an eighth aspect, a communication device is provided, which may be an access network device or a chip in an access network device. The device may include a processing unit and a transceiver unit. When the device is an access network device, the processing unit may be a processor, and the transceiver unit may be a transceiver; the access network device may further include a storage unit, and the storage unit may be a memory; the storage unit is used to store instructions, and the processing unit executes the instructions stored in the storage unit so that the network device executes the method in the third aspect. When the device is a chip in a network device, the processing unit may be a processor, and the transceiver unit may be an input / output interface, a pin or a circuit, etc.; the processing unit executes the instructions stored in the storage unit so that the network device executes the method in the third aspect, and the storage unit may be a storage unit in the chip (for example, a register, a cache, etc.), or a storage unit located outside the chip in the access network device (for example, a read-only memory, a random access memory, etc.).

[0062] In a ninth aspect, a communication device is provided, comprising at least one processor, wherein the at least one processor is used to couple with a memory, read and execute instructions in the memory to implement any one of the methods in the first aspect, the second aspect or the third aspect.

[0063] Optionally, the communication device also includes the memory.

[0064] In a tenth aspect, a computer program product is provided, the computer program product comprising: a computer program code, when the computer program code is run on a computer, the computer executes the method in the first aspect, the second aspect or the third aspect above.

[0065] It should be noted that the above-mentioned computer program code can be stored in whole or in part on the first storage medium, wherein the first storage medium can be packaged together with the processor or separately from the processor, and this application does not make any specific limitation on this.

[0066] In the eleventh aspect, a computer-readable medium is provided, wherein the computer-readable medium stores a program code, and when the computer program code runs on a computer, the computer executes the method in the first aspect, the second aspect or the third aspect.

[0067] In the twelfth aspect, a chip system is provided, comprising a processor for calling and running a computer program from a memory, so that a communication device equipped with the chip system executes the method in the first, second or third aspect above.

[0068] In the thirteenth aspect, a communication system is provided, which includes at least one of the communication device provided in the fourth aspect, the communication device provided in the fifth aspect, and the communication device provided in the sixth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a schematic diagram of a communication system provided in an embodiment of the present application.

[0070] Figure 2 It is a schematic diagram of the conversion relationship between the three RRC states provided in an embodiment of the present application.

[0071] Figure 3 This is a flowchart of a four-step contention-based random access provided in an embodiment of the present application.

[0072] Figure 4 It is a schematic diagram of the deregistration process provided in an embodiment of the present application.

[0073] Figure 5 It is a schematic flowchart of an example of a communication method provided in an embodiment of the present application.

[0074] Figure 6 It is a schematic flowchart of another example of the communication method provided in an embodiment of the present application.

[0075] Figure 7 It is a schematic diagram of three terminal devices supporting dual SIM provided in an embodiment of the present application.

[0076] Figure 8 It is a schematic flowchart of another example of the communication method provided in an embodiment of the present application.

[0077] Fig. 9 It is a schematic block diagram of an example of a communication device provided in an embodiment of the present application.

[0078] Fig.10 It is a schematic diagram of the structure of the terminal device provided in an embodiment of the present application.

[0079] Fig.11 This is another schematic block diagram of a communication device provided in an embodiment of the present application.

[0080] Fig.12 It is a structural diagram of the access network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0081] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0082] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, fifth generation (5G) communication system or new radio (NR) system, or new wireless communication systems that will evolve in the future.

[0083] To facilitate understanding of the embodiments of the present application, first Figure 1 The communication system shown in the figure is used as an example to describe in detail the communication system applicable to the embodiments of the present application. Figure 1 1 is a schematic diagram of a communication system 100 provided in an embodiment of the present application. Figure 1 As shown, the communication system 100 may include at least one access network device (e.g., Figure 1 The access network device 101 shown in FIG. 1 and at least one terminal device (eg, Figure 1 The access network device 101 may wirelessly communicate with the terminal device 102. Optionally, the communication system 100 may further include more access network devices and / or more terminal devices, which is not limited in the present application.

[0084] Furthermore, if Figure 1 As shown, the communication system 100 provided in the present application also includes at least one core network device (for example, Figure 1 The core network device 103 shown in FIG. 1 may be connected to the access network device 101 in a communication manner (eg, connected by wire). Optionally, the communication system 100 may further include more core network devices, which is not limited in the present application.

[0085] The access network equipment may include equipment in the access network that communicates with the wireless terminal over the air interface through one or more sectors. The access network system may be used to convert received air frames to and from Internet Protocol (IP) packets, acting as a router between the wireless terminal and the rest of the access network, which may include an IP network. The wireless access network system may also coordinate the management of attributes of the air interface. It should be understood that the access network equipment includes but is not limited to: evolved Node B (eNB), Radio Network Controller (RNC), Node B (NB), Base Station Controller (BSC), Base Transceiver Station (BTS), Home base station (for example, Home evolved NodeB, or HomeNode B, HNB), Baseband Unit (BBU), Access Point (AP) in Wireless Fidelity (WIFI) system, wireless relay node, wireless backhaul node, transmission point (TRP or transmission point, TP), etc., and can also be a gNB in ​​5G, such as NR, system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or, it can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU), etc.

[0086] In some deployments, the gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some functions of the gNB, and the DU implements some functions of the gNB, for example, the CU implements the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, and the DU implements the functions of the radio link control (RLC), media access control (MAC) and physical (PHY) layers. Since the information of the RRC layer will eventually become the information of the PHY layer, or be converted from the information of the PHY layer, therefore, under this architecture, high-level signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by the DU+CU. It can be understood that the access network device can be a CU node, a DU node, or a device including a CU node and a DU node. In addition, the CU may be classified as an access network device in a radio access network (RAN), or the CU may be classified as an access network device in a core network (CN), and no limitation is made here.

[0087] The terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiments of the present application may be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid (smartgrid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smartcity), a wireless terminal in smart home (smart home), etc. The embodiments of the present application do not limit the application scenarios.

[0088] The core network device refers to the device in the core network (CN) that provides service support for the terminal device. The core network device in the embodiment of the present application can be used to implement functions such as call connection, billing, mobility management and supplementary services. In the 5G system, the core network device may include, for example, an access and mobility management function (AMF) entity, a session management function (SMF) entity, a user plane function (UPF) entity, a policy control function (PCF) entity and a unified data management (UDM) entity. The embodiment of the present application mainly involves communication with the AMF entity. Therefore, a brief description of the AMF entity is given here. The AMF entity may also be referred to as AMF, which is mainly used for mobility management and access management, etc., and can be used to implement other functions in the mobility management entity (MME) function except session management. For example, functions such as legal monitoring and access authorization (or authentication). In the following, the AMF in 5G is used as an example of a network element for mobility and access management, which should not constitute any limitation to this application. This application does not exclude the possibility of using other network elements to replace AMF to achieve the same or similar functions. It should be noted that the entity in the embodiment of the present application can also be called a network element or a functional entity. For example, the AMF entity can also be called an AMF network element or an AMF functional entity.

[0089] To facilitate understanding of the embodiments of the present application, some technical concepts and communication processes that may be involved in the embodiments of the present application are first illustrated by examples.

[0090] 1. Public Network

[0091] Normally, the public network provides network services for terminal devices. The public network, namely the public land mobile network (PLMN), is a network established and operated by the government or its approved operators to provide land mobile communication services to the public. This network is usually interconnected with the public switched telephone network (PSTN) to form a communication network on a regional or national scale.

[0092] Different PLMN networks can be distinguished by different PLMN identifications (IDs). PLMN identification consists of a mobile contrary code (MCC) and a mobile network code (MNC). The MCC uniquely identifies the country to which the mobile user belongs, for example, China's MCC is 460. The MNC uniquely identifies a network in the country, for example, China Mobile's MNC is 00 and China Unicom's MNC is 01.

[0093] 2. Private Network

[0094] In addition to the public network, operators or individuals will also build some private networks (non-public networks, NPN) to meet the needs of users. Private networks can also be called non-public networks, which refer to networks open to specific users, such as internal networks built by companies, schools or factories. Terminal devices that have not signed contracts with private networks are not allowed to access private networks. Private networks are divided into non-independent private networks and independent private networks.

[0095] (1) Non-independent private network

[0096] The network resources (such as access network equipment, core network equipment, spectrum resources, etc.) used by the non-stand-alone non-public network (NSA-NPN, or publicnetwork integrated non-public network, PNI-NPN) are part of the public network. It can also be considered that the non-stand-alone private network depends on the public network, or that the non-stand-alone private network is based on the public network. The non-stand-alone private network is also called a closed access group (CAG). The identification of the non-stand-alone private network consists of two parts, namely the PLMN ID and the CAG ID, among which the PLMN ID of the non-stand-alone private network is consistent with the public network it depends on.

[0097] According to the current communication protocol, since the non-independent private network uses public network resources, mobility is supported between the non-independent private network and the public network it relies on. That is, some terminal devices can switch and / or reselect cells between the non-independent private network and the public network. Switching means that a connected terminal device disconnects from the current service cell and connects to the target cell under the control of the base station. Cell reselection means that when an idle / deactivated terminal device resides in a cell, as the terminal device moves, the terminal device may need to switch to another cell with a higher priority or better signal. This is the cell reselection process.

[0098] (2) Independent private network

[0099] A stand-alone non-public network (SNPN) is a private network that does not rely on the network functions of the public network. Similarly, the identification of a stand-alone non-public network is also divided into two parts, namely, the PLMN ID and the NID.

[0100] Independent private networks have independent access networks (radio access networks, RAN) and / or core networks (core networks, CN). Therefore, independent private networks usually do not support mobility between other networks. For example, independent private networks do not support mobility between public networks, non-independent private networks, non-terrestrial networks (NTNs) and other independent private networks. In other words, independent private networks do not support terminal devices to switch and reselect cells between independent private networks and public networks, non-independent private networks, non-terrestrial networks and other independent private networks. That is, a terminal device in a connected state cannot switch from an independent private network cell to a public network cell, a non-independent private network cell, a non-terrestrial network cell and other independent private network cells, and vice versa; a terminal device in an idle state / deactivated state cannot reselect from an independent private network cell to a public network cell, a non-independent private network cell, a non-terrestrial network cell and other independent private network cells, and vice versa.

[0101] 3. RRC Status

[0102] In the 5G system, the RRC states of the terminal device include RRC connected state (RRC_CONNECTED), RRC deactivated state or RRC third state (RRC_INACTIVE), and RRC idle state (RRC_IDLE). Figure 2 It is a schematic diagram of the conversion relationship between the three RRC states provided in an embodiment of the present application.

[0103] Among them, when the terminal device is in the RRC connected state, the terminal device has established links with the base station and the core network. When data arrives at the network, it can be directly transmitted to the terminal device; when the terminal device is in the RRC third state (or RRC deactivated state), it means that the terminal device has previously established links with the base station and the core network, but the link from the terminal device to the base station has been released. Although the link is released, the base station will store the context of the terminal device. When there is data to be transmitted, the base station can quickly restore this link; when the terminal device is in the RRC idle state, there is no link between the terminal device and the base station and the core network. When there is data to be transmitted, a link from the terminal device to the base station and the core network needs to be established.

[0104] 4. Paging

[0105] When the terminal device is in idle or deactivated state, the connection between the terminal device and the base station is disconnected. At this time, if the network side has downlink data to send to the terminal device, it will find the terminal device through a paging message. After the terminal device receives the paging message and confirms that it is being paged, it will establish a connection with the base station for data transmission. Paging can usually be divided into core network paging (CN paging) and access network paging (RAN paging). The following will further introduce these two types of paging.

[0106] Core network paging is initiated by core network equipment (such as AMF in 5G system or MME in LTE system), mainly for idle terminal devices, based on tracking area (TA). When downlink data arrives at the core network equipment (that is, the network wants to send data to the terminal device), the core network equipment sends a paging message to all base stations included in the tracking area identity (TA identity, TAI) list of the terminal device, and these base stations then transparently transmit it to all terminal devices connected to their related cells. The terminal device that monitors the paging message will check whether it contains its own identity. If so, it will initiate an RRC establishment request to connect to the network; if not, it will ignore the paging request.

[0107] Access network paging is mainly for inactive terminal devices, based on the access network notification area (RAN-based notification area, RNA). Access network paging is initiated by the last serving base station before the terminal device enters the deactivated state from the connected state. Because the terminal device enters the deactivated state, the core network device (such as AMF) side is not aware of it. From the core network device's point of view, this terminal device is still in the connected state, so it will continue to send data to the last serving base station. After the last serving base station cannot find the terminal device, it will send paging messages to all base stations involved in the access network paging area (RAN paging area) where the terminal device is located. These base stations will then transparently transmit to all terminal devices connected to them. The terminal device that monitors the paging message will check whether it contains its own identity. If so, it will initiate an RRC recovery request and connect to the network; if not, it will ignore the paging request.

[0108] 5. Random Access

[0109] In the 5G system, the following situations usually require a random access process: initial access of the terminal device, transition from the idle state / deactivated state to the connected state; re-establishing the RRC connection after the wireless connection is interrupted; when switching, the terminal device needs to establish uplink synchronization with the target cell; when the terminal device is in the connected state but the terminal device is not synchronized uplink, uplink or downlink data arrives at this time, and uplink synchronization needs to be established through random access; when using uplink measurement-based user positioning; when no dedicated scheduling request resources are allocated on the physical uplink control channel (PUCCH), uplink resources are requested through random access.

[0110] The types of random access include contention-based random access, non-contention-based random access, four-step random access, two-step random access, etc. Figure 3 is a flow chart of the four-step contention-based random access.

[0111] 110, random access initialization.

[0112] 120. The terminal device sends a random access preamble to the base station.

[0113] The random access preamble is carried in the first message (Msg1). The main function of the random access preamble is to tell the base station that there is a random access request and enable the base station to estimate the transmission delay between it and the terminal device so that the base station can calibrate the uplink advance (uplink timing) and inform the terminal device of the calibration information through the timing advance command (timing advance command).

[0114] 130. The terminal device receives a random access response (RAR) sent by the base station.

[0115] RAR is carried in the second message (Msg2). After the terminal device sends the preamble, it will monitor the corresponding physical downlink control channel (PDCCH) in the RAR response window according to the random access radio network temporary identifier (RA-RNTI) corresponding to the preamble. If the preamble carried in the response received by the terminal device is consistent with the preamble sent by Msg1, it stops monitoring RAR.

[0116] The RAR includes an uplink timing advance, an uplink grant (UL grant) allocated for the third message (Msg3), a temporary cell radio network temporary identifier (cell radio network temporary identifier, temporary C-RNTI) allocated by the network side, and the like.

[0117] 140. The terminal device sends a message based on scheduled transmission (ie, Msg3) to the network device.

[0118] The terminal device sends Msg3 to the base station according to the uplink authorization and uplink timing advance information in Msg2. Here, the content of Msg3 may also be different depending on the different states of the terminal device and different application scenarios.

[0119] Msg3 can be divided into the following types: RRC connection request, tracking area data update, resource scheduling request, etc.

[0120] 150. The terminal device receives the contention resolution sent by the network device, that is, the fourth message Msg4.

[0121] When multiple terminal devices initiate random access using the same preamble, contention occurs. Among the terminal devices competing for the same resources, at most only one terminal device can access successfully. At this time, the base station sends a contention resolution message to the terminal device through the physical downlink shared channel (PDSCH). If the terminal device receives the contention resolution message sent to it by the base station, it is considered that the random access process is successful.

[0122] 6. Registration Process

[0123] After a connected terminal device registers with a network, it needs to be in a deregistered state (i.e., it needs to leave the network) for some reason, and needs to initiate a deregistration process. For example, before the phone is turned off, the terminal device will initiate a deregistration process to notify the network that the terminal device will no longer be in this network. A similar process is called a deattachment process in the LTE system. Figure 4 It is a schematic diagram of the deregistration process provided in an embodiment of the present application.

[0124] like Figure 4As shown, in step 201, when the terminal device needs to leave the network, a deregistration process is initiated, a deregistration request message is sent to the access network device (e.g., gNB), and the identity of the terminal device is carried in the deregistration request message. Optionally, the network can be any one of a public network, an independent private network, a non-independent private network, a non-terrestrial network, etc.

[0125] In step 202, the access network device forwards the deregistration request message to the core network device. Optionally, the deregistration request message may be transmitted through a non-access stratum (NAS), that is, the terminal device transparently transmits the deregistration request message to the core network device through the access network device.

[0126] In step 203, the core network device receives the deregistration request message, and after completing the relevant deregistration procedures on the core network side (which may involve multiple signaling interactions with other core network devices, which will not be explained here), sends a deregistration accept message to the access network device. Optionally, the core network device may be an AMF.

[0127] In step 204, the access network device forwards the deregistration acceptance message to the terminal device. After receiving the deregistration acceptance message, the terminal device releases the signaling connection with the network side and completes the deregistration process. At this point, the terminal device has almost no context on the core network device side (except for a small amount of information for authentication convenience), and it can be simply considered that the terminal device no longer exists in this network.

[0128] It should be understood that in actual applications, in order to save signaling overhead, the core network device or the access network device may not send a deregistration acceptance message. For example, when the core network device or the access network device determines that the terminal device is deregistering because it is powered off, it may not send a deregistration acceptance message to the terminal device. That is, the above steps 203 and 204 are optional steps.

[0129] 7. Network Selection

[0130] In recent years, in order to meet the usage needs of different users, terminal devices that support access to multiple different networks have emerged. For example, for a certain terminal device, it not only has the ability to access the public network, but also has the ability to access an independent private network. At this time, a switch for independent private network access mode (SNPN access mode) can be set on the terminal device (for example, it can be similar to a WIFI switch), and the user can choose whether to turn on the independent private network access mode by turning the switch on or off, and then choose which network to enter. For example, when the user turns on the switch, the user can only choose independent private network access, but cannot choose public network access. Correspondingly, when the user turns off the switch, the user can only choose public network access, but cannot choose independent private network access.

[0131] Specifically, when the independent private network access mode is not turned on, the terminal device can access the public network, and also reside in the public network cell when the terminal device enters the idle state or the deactivated state, and when the independent private network access mode is turned on (for example, the user manually turns on the switch of the independent private network access mode), the terminal device will leave the public network and start to access the independent private network. At this time, the terminal device can select according to the network list broadcast by the independent private network cell, and the selection process is generally divided into automatic network selection and manual network selection. Here, network selection can be the process of the terminal device selecting a network identifier, for example, in PLMN and CAG, the PLMN ID is selected, and in SNPN, the PLMN ID and NID are selected.

[0132] (1) Automatic network selection

[0133] In this mode, the terminal device will select an independent private network with a subscription permanent identifier (SUPI) and a certificate and try to register, that is, the terminal device will find an independent private network that has been authenticated for registration. When there are multiple independent private networks that can be registered, that is, the terminal device has searched for multiple authenticated independent private networks, the terminal device will select an independent private network for registration. The selection process belongs to the internal implementation of the terminal device and will not be explained here.

[0134] (2) Manual network selection

[0135] In this mode, the terminal device will provide the human-readable names (such as Huawei private networks) of the networks in the network list broadcast by the independent private network cell to the user. The user selects the independent private network based on the user's selection (the operation may be to click to select, similar to the user selecting a WIFI network). The UE registers in the relevant independent private network based on the user's selection.

[0136] When the independent private network access mode remains on, the terminal device will also reside in the independent private network cell when it enters the idle state or deactivated state. When the independent private network access mode is turned off, the terminal device will leave the independent private network and start to access the public network. At this time, the terminal device will first select the corresponding public network, and then select the cell. Specifically, the terminal device first selects a suitable network from the searched public network list as the service network of the terminal device, and then searches for various cells under the network, and selects a suitable cell as the service cell of the terminal device.

[0137] According to the existing protocol progress, for terminal devices that support independent private network functions, once the state of the independent private network access mode changes, whether it is turned on or off, the terminal device will re-select the network between the public network and the independent private network. When selecting the target network, if the terminal device is in an idle state or deactivated state, since the connection between the terminal device and the base station has been released, the two cannot communicate. The terminal device will silently leave the original network without notifying the base station and core network equipment of the original network (such as AMF in the 5G system, or MME in LTE). In this way, from the perspective of the original network, this terminal device is still an idle terminal device in the original network, and it does not know that the terminal device has gone to other networks.

[0138] This inconsistency between the status of the terminal side and the original network side will cause many problems. For example, the original network side continues to maintain the context of the terminal device. At this time, if the original network side has data to send to the terminal device, it will find the terminal device through a paging message. However, since the terminal device has gone to other networks and cannot receive the paging message, the base station on the original network side will continue to page the terminal device, resulting in a large amount of NG port and air interface resource waste, and also a waste of base station power.

[0139] Based on the above problems, the present application provides a communication method, a communication device and a communication system, which can avoid invalid paging on the original network side and save air interface resources and power of access network equipment.

[0140] It is understandable that in the embodiments of the present application, the terminal device and / or the network device (such as the access network device and / or the core network device) can perform some or all of the steps in the embodiments of the present application, and these steps or operations are only examples. The embodiments of the present application can also perform other operations or variations of various operations. In addition, the various steps can be performed in different orders presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed.

[0141] The following describes the communication method provided by the embodiment of the present application in conjunction with the accompanying drawings. The access network device in the embodiment may be Figure 1 The access network device 101 in the embodiment may be Figure 1 The terminal device 102 in the embodiment may be a core network device Figure 1 The core network device 103 in.

[0142] Figure 5 is a schematic flow chart of the communication method 200 provided by the present application. Figure 5 The communication method 200 provided in an embodiment of the present application is described. The method 200 includes:

[0143] Step 210, a terminal device residing in a first network in a radio resource control RRC idle state or an RRC deactivated state determines that it needs to enter a second network through network selection;

[0144] Step 220, the terminal device enters the RRC connected state;

[0145] Step 230: The terminal device initiates a registration process to the first network.

[0146] Specifically, in the embodiment of the present application, the terminal device can access the first network and can also access the second network, that is, the terminal device in the embodiment of the present application has the ability to access multiple different networks and can make a network selection between the first network and the second network.

[0147] When the terminal device determines that it needs to leave the first network and enter the second network through the network, if the terminal device is currently residing in the first network in the RRC idle state or the RRC deactivated state, the terminal device will first enter the RRC connected state and initiate a deregistration process to the first network. It will leave the first network only after the deregistration process is completed.

[0148] In the embodiment of the present application, the terminal device initiates a deregistration process to the first network, which means that the terminal device deregisters in the first network so that it is in a deregistered state in the first network. After the deregistration process is completed, the context of the terminal device in the first network almost disappears (except for a small amount of information for facilitating authentication). The first network will know that the terminal device has left the network, and when the data of the terminal device arrives on the first network side, it will not page the terminal device. In some cases, the deregistration of the present application can also be understood as deattachment.

[0149] According to an embodiment of the present application, a terminal device in an RRC idle state or an RRC deactivated state will first enter an RRC connected state before leaving the first network, and deregister in the first network through a deregistration process, informing the first network that it is about to leave. Through the above settings, invalid paging of the terminal device by the first network can be avoided, saving air interface resources and power of access network equipment.

[0150] Optionally, the deregistration process may be as described above. Figure 4 The deregistration process shown may also be other forms of deregistration processes, which are not limited in this application.

[0151] Optionally, in addition to being able to access the first network and the second network, the terminal device may also have the ability to access other networks, which is not limited in this application.

[0152] In step 210, the terminal device determines that it needs to enter the second network through network selection, that is, the terminal device determines that it needs to leave the first network and enter the second network through network selection.

[0153] Optionally, the first network may be a public network, and the second network may be an independent private network. The terminal device may determine that it needs to enter the second network through network selection according to a change in the independent private network access mode state.

[0154] Optionally, the network selection may be an automatic network selection or a manual network selection by a user, which is not limited in the present application.

[0155] In the embodiment of the present application, the first network and the second network are two different networks, and the types of the first network and the second network can be the same or different, and the present application does not limit this. For example, the first network can be any one of a public network, an independent private network, a non-independent private network, a non-terrestrial network, etc., and the second network can also be any one of a public network, an independent private network, a non-independent private network, a non-terrestrial network, etc.

[0156] The standards of the first network and the second network may be the same or different, and this application does not limit this. For example, the standards may include a 5G system, an LTE system, a WCDMA system, a code division multiple access CDMA system, and a GSM system.

[0157] Optionally, mobility may be supported between the first network and the second network. The following is an example to illustrate the support of mobility.

[0158] Optionally, supporting mobility between the first network and the second network may mean that the terminal device can perform cell switching and cell reselection between the first network and the second network.

[0159] Optionally, supporting mobility between the first network and the second network may mean that the first network and the second network share the same core network device (for example, share the same AMF, which is explained below using AMF as an example).

[0160] Optionally, supporting mobility between the first network and the second network may mean that control plane signaling can be interacted between the AMFs of the first network and the second network.

[0161] For example, the first network may be a public network, and the second network may be a non-independent private network that depends on the public network. Alternatively, the first network may be a non-independent private network, and the second network may be a public network that the non-independent private network depends on.

[0162] For another example, the first network and the second network may be two non-independent private networks that rely on the same public network.

[0163] In the embodiment of the present application, optionally, mobility may not be supported between the first network and the second network. The following is an example of not supporting mobility.

[0164] Optionally, mobility is not supported between the first network and the second network, which may mean that the terminal device cannot perform cell switching and cell reselection between the first network and the second network.

[0165] Optionally, mobility is not supported between the first network and the second network, which may mean that the first network and the second network respectively use their own AMFs, and control plane signaling cannot be interacted between the AMFs.

[0166] For example, the first network may be an independent private network, and the second network may be any one of a public network, a non-independent private network, a non-terrestrial network, and other independent private networks.

[0167] For another example, the first network may be any one of a public network, a non-independent private network, a non-terrestrial network, and an independent private network, and the second network may be another independent private network.

[0168] Mobility is not supported between the first network and the second network, so that the core network device of the first network cannot exchange the context information of the terminal device between the core network devices of the second network, that is, the core network device cannot actively initiate the deregistration process of the terminal device, which makes the method 200 provided in the embodiment of the present application more meaningful.

[0169] In step 220, the terminal device enters the RRC connected state from the RRC idle state or the RRC deactivated state, that is, at this time, the terminal device and Figure 5 An RRC connection is established or restored between the access network devices shown.

[0170] Optionally, the access network device may be an access network device that previously provided services to the terminal device, or may be other access network devices, which is not limited in this application.

[0171] Optionally, the cell connected to the terminal device at this time may be the cell where the terminal device resides, or may be other cells in the first network, and this application does not limit this.

[0172] Optionally, the terminal device is connected to a first cell, the first cell is a cell of the first network where the terminal device currently resides, or the first cell is another cell of the first network. That is, at this time, the terminal device is connected to the first network to initiate a deregistration process to the first network.

[0173] Optionally, the method 200 provided in the embodiment of the present application also includes step 240.

[0174] In step 240, after completing deregistration in the first network, the terminal device enters the second network through network selection.

[0175] Optionally, the terminal device may enter the second network through automatic network selection or manual network selection, which is not limited in this application.

[0176] Figure 6 FIG. 2 is a schematic flow chart of an embodiment of the communication method 200. Figure 6 As shown, depending on the state of the terminal device, the process of the terminal device entering the RRC connection state in step 220 may be different.

[0177] Specifically, in step 210, if the terminal device resides in the first network in the RRC idle state, step 220 further includes steps 221a, 222a, and 223a.

[0178] In step 221a, the terminal device sends an RRC setup request message to the access network device through random access to request to establish an RRC connection with the access network device. The RRC setup request message may carry information such as the terminal device identifier and the connection establishment reason.

[0179] Optionally, the random access may be any one of contention-based random access, non-contention-based random access, four-step random access, and two-step random access.

[0180] Optionally, the RRC establishment request message may be the aforementioned Figure 3 The third message (Msg3) in the four-step contention-based random access is shown.

[0181] In step 222a, the terminal device receives an RRC setup message sent by the access network device. The access network device determines that it agrees to establish an RRC connection with the terminal device, and then sends an RRC setup message to the terminal device, and the RRC setup message carries a series of configuration information.

[0182] Optionally, the RRC establishment message may be the aforementioned Figure 3 The fourth message (Msg4) in the four-step contention-based random access is shown.

[0183] In step 223a, the terminal device sends an RRC setup complete message to the access network device.

[0184] The terminal device establishes an RRC connection with the access network device through the above steps. The access network device can be an access network device in the first network. That is, the terminal device in the idle state can establish an RRC connection with the first network and initiate a registration process to the first network.

[0185] In step 210, if the terminal device resides in the first network in an RRC deactivated state, step 220 further includes steps 221b, 222b, and 223b.

[0186] In step 221b, the terminal device sends an RRC resume request (RRCresume request) message to the access network device through random access to request to restore the RRC connection with the access network device.

[0187] Optionally, the random access may be any one of contention-based random access, non-contention-based random access, four-step random access, and two-step random access.

[0188] Optionally, the RRC recovery request message may be the aforementioned Figure 3 The third message (Msg3) in the four-step contention-based random access is shown.

[0189] In step 222b, the terminal device receives an RRC resume message sent by the access network device. If the access network device determines that it agrees to resume the RRC connection with the terminal device, it sends an RRC resume message to the terminal device.

[0190] Optionally, the RRC recovery message may be the aforementioned Figure 3 The fourth message (Msg4) in the four-step contention-based random access is shown.

[0191] In step 223b, the terminal device sends an RRC resume complete message to the access network device.

[0192] The terminal device restores the RRC connection with the access network device through the above steps. Since the terminal device originally resides in the first network, through the above steps, the terminal device can restore the RRC connection with the first network and initiate a registration process to the first network.

[0193] In step 230, the terminal device initiates a registration process to the first network. This application does not limit how the terminal device initiates the process. Figure 5As shown, in the embodiment of the present application, step 230 further includes step 231.

[0194] In step 231, the terminal device sends a deregistration request message to the access network device. The deregistration request message may include an identifier of the terminal device to request the terminal device to deregister in the first network.

[0195] Optionally, the deregistration request message may be carried in the aforementioned RRC setup completion message or RRC recovery message, that is, the deregistration request message may be sent together with the aforementioned RRC setup completion message or RRC recovery message as one message, thereby saving signaling overhead.

[0196] Optionally, the terminal device identifier can be a 5G globally unique temporary identity (5G-GUTI). The 5G-GUTI can be composed of a globally unique AMF identifier (GUAMI) and a 5G temporary mobile user identifier (5G s-temporary mobile subscriber identity, 5G-S-TMSI). After receiving the 5G-GUTI, the access network device can find the AMF registered by the terminal device based on the GUAMI.

[0197] It is easy to understand that the terminal device initiates a deregistration process to the first network, and the identifier of the terminal device included in the deregistration request message should be the identifier of the terminal device in the first network.

[0198] Optionally, the deregistration request message further includes deregistration type indication information, and the deregistration type information may indicate that the reason for the terminal device to deregister is to go to another network.

[0199] For example, the deregistration type information may indicate that the terminal device has gone to an independent private network, a non-independent private network or a public network, or a non-terrestrial network (in this case, the type of the second network is an independent private network, a non-independent private network or a public network, or a non-terrestrial network).

[0200] For another example, the deregistration type information may indicate that the terminal device has gone to the second network.

[0201] Optionally, the deregistration request message further includes network selection indication information, which is used to indicate that the reason for the terminal device to deregister is to select another network through network selection. For example, the network selection indication information can be a specially set information element in the deregistration request message, and the information element can be one or more bits, which is not limited in this application.

[0202] Further, the core network device determines, based on the deregistration request message (for example, based on the deregistration type information and / or network selection indication information therein), that the reason for the terminal device to deregister is that it has selected another network through the network. At this time, the core network device may choose to retain (or suspend) the context information of the terminal device instead of releasing the context information. The above settings can help the terminal device quickly enter the first network next time.

[0203] Optionally, the deregistration request message may further include access type indication information, where the access type indication information is used to indicate in which network the deregistration request message is applied.

[0204] For example, the type of the first network can be any one of an independent private network, a non-independent private network, a public network, a non-terrestrial network, etc. The deregistration type information can indicate that the deregistration request message is applied in an independent private network, a non-independent private network, a public network, a non-terrestrial network, etc.

[0205] For another example, the access type indication information is used to indicate that the deregistration request message is applied in the first network.

[0206] Optionally, the deregistration process may further include steps 232 , 233 , and 234 .

[0207] In step 232, the access network device sends a deregistration request message to the core network device.

[0208] In step 233, the core network device sends a deregistration acceptance message to the access network device.

[0209] In step 234, the access network device sends a deregistration acceptance message to the terminal device.

[0210] Specifically, after receiving the deregistration request message, the access network device finds the core network device registered by the terminal device according to the GUAMI in the message, and forwards the deregistration request message to the core network device. Optionally, the deregistration request message can be transmitted through the NAS layer, that is, the terminal device transparently transmits the deregistration request message to the core network device through the access network device.

[0211] Optionally, the core network device may be an AMF.

[0212] The core network device receives the deregistration request message and sends a deregistration acceptance message to the access network device after completing the relevant deregistration procedure on the core network side.

[0213] The access network device forwards the deregistration acceptance message to the terminal device. After receiving the deregistration acceptance message, the terminal device releases the signal connection with the network side and completes the deregistration process. At this point, the terminal device has almost no context on the core network device side (except for a small amount of information for authentication convenience), and it can be simply considered that the terminal device no longer exists in this network.

[0214] Currently, more and more terminal devices support the simultaneous insertion of two subscriber identification module (SIM) cards. For example, one SIM card is used for private business and the other SIM card is used for work business; or one SIM card is used for data business and the other SIM card is used for voice business. This business mode can be called dual-card mode. The dual cards can belong to the same mobile operator or different mobile operators, or the dual cards can belong to the same standard or different standards. For example, the standards may include 5G system, LTE system, WCDMA system, CDMA system and GSM system, etc.

[0215] The terminal device supporting two SIM cards may also be referred to as a terminal device supporting two "user identities". The "user identity" is further described below.

[0216] In the embodiments of the present application, "user identity" (such as the first user identity or the second user identity) is a logical concept. For example, "user identity" may correspond to a subscriber identification module (SIM) card or subscriber information or a virtual SIM card or a user identity (such as an international mobile subscriber identity (IMSI) or a temporary mobile subscriber identity (TMSI), etc.). From the perspective of the network side, different "user identities" logically correspond to different communication entities served by the network side. For example, a terminal device that supports two user identities can be regarded as two communication entities for the network side. For another example, when the "user identity" corresponds to a SIM card or subscriber information, the network side will identify the same terminal device with multiple different SIM cards or multiple subscriber information as multiple different communication entities, even if in fact, the terminal device that supports multiple different SIM cards or multiple subscriber information is only one physical entity. It should be noted that in the embodiments of the present application, the "user identity" corresponding to the SIM card will be mainly used as an example for explanation.

[0217] Exemplarily, a SIM card can be understood as a key for a terminal device to access a mobile network. For ease of description, in the embodiments of the present application, SIM cards and their evolutions are collectively referred to as SIM cards. For example, a SIM card can be an identity card for a user of a global system for mobile communications (GSM) digital mobile phone, which is used to store the user's identity code and key and support the GSM system's authentication of the user; for another example, a SIM card can also be a universal subscriber identity module (USIM), which can also be called an upgraded SIM card; for another example, a SIM card can also be a universal integrated circuit card (UICC) or an embedded SIM card (eSIM) or a soft SIM card, etc., which can identify the user's identity. The embodiments of the present application are described with a SIM card, which does not constitute a limitation on the present application.

[0218] The following describes a terminal device supporting two user identities, such as a terminal device supporting two SIM cards, wherein a base station of one SIM card can also be said to be a base station corresponding to one user identity in the terminal device, and can also be understood as the base station serving the communication entity corresponding to the SIM card. Figure 7 The following are schematic diagrams of three terminal devices supporting dual SIM cards provided in the embodiments of the present application. According to the different transceiver capabilities of the terminal devices, the terminal devices including dual SIM cards can be divided into the following three modes.

[0219] Figure 7 (a) is the passive mode. Although two SIM cards can be inserted, only one SIM card can be used at the same time, that is, it can receive and send, and the other card is unused.

[0220] Figure 7(b) is the dual SIM dual standby (DSDS) mode, where two SIM cards share a set of transceivers, and the terminal device in the RRC idle state needs to monitor the paging messages of the two cards, for example, by using time-division multiplexing (TDM) to monitor. When there is an RRC connection between the terminal device and the base station of one of the SIMs (e.g., SIM 1), it can also be said that SIM 1 enters the RRC connection state, or enters the RRC connection state as the first user, that is, it can send and receive data. The terminal device cannot maintain an RRC connection with the base station of another SIM (e.g., SIM 2), and it can also be said that SIM 2 is in the RRC idle state or RRC deactivated state, or in the RRC idle state or RRC deactivated state as the second user.

[0221] Figure 7 (c) Dual SIM dual active (DSDA) mode: two SIM cards correspond to their own transceivers. The two SIM cards can be in RRC connection state at the same time, or in other words, in RRC connection state with two users at the same time, that is, the terminal device can receive and send data from the two SIM cards at the same time.

[0222] It is easy to understand that Figure 5 , 6 The terminal device in the method 200 shown may be a terminal device with only one SIM card, or in other words, has only one user identity, which can access the first network and the second network. When the user identity needs to leave the first network and enter the second network through network selection, the user identity in the RRC idle state or the RRC deactivated state can enter the RRC connected state and initiate a deregistration process to the first network so that the user identity is deregistered in the first network.

[0223] In addition, the terminal device in method 200 may also have two or more SIM cards, or two or more user identities, but method 200 is mainly for a certain user identity (recorded as user identity #1) among the multiple user identities. Specifically, the user identity #1 can access the first network and the second network. When the user identity #1 needs to leave the first network and enter the second network through the network selection, the user identity #1 in the RRC idle state or the RRC deactivated state can enter the RRC connected state and initiate a deregistration process to the first network by itself.

[0224] On this basis, the present application also provides a communication method 300, which is applicable to the aforementioned terminal device with dual SIM cards or even more SIM cards, or in other words, the communication method 300 is applicable to a terminal device with two or more user identities. The difference from the aforementioned method 200 is that in method 300, when one of the user identities (recorded as the first user identity) needs to be deregistered, the deregistration process of the first user identity can be initiated by other user identities (recorded as the second user identity).

[0225] The following describes a communication method 300 provided in an embodiment of the present application in conjunction with the accompanying drawings. Figure 8 300 is a schematic flow chart of the communication method 300 provided in the present application. In the embodiment of the present application, only a terminal device supporting two user identities (for example, supporting dual SIM cards) is used for explanation. It should be understood that the communication method 300 of the embodiment of the present application can also be applied to a terminal device supporting more than two user identities (for example, supporting 3, 4 or more SIM cards). The method 300 includes:

[0226] Step 310, the terminal device determines that the first user identity needs to be deregistered in the first network, and the terminal device supports the first user identity and the second user identity;

[0227] Step 320: The terminal device sends a deregistration request message to the access network device as the second user identity. The deregistration request message carries the identifier of the first user identity. The deregistration request message is used to request the first user identity to deregister in the first network.

[0228] Accordingly, in step 320, the access network device receives the deregistration request message sent by the terminal device.

[0229] In step 330, the access network device sends the deregistration request message to the core network device.

[0230] Correspondingly, the core network device receives the deregistration request message sent by the access network device.

[0231] In an embodiment of the present application, the terminal device supports a first user identity (e.g., SIM#1) and a second user identity (e.g., SIM#2). The first user identity can access the first network and has been connected to the first network. At this time, the core network device of the first network (e.g., AMF) stores the context information of the first user identity.

[0232] When the terminal device determines that the first user identity needs to be deregistered (or detached) in the first network, the terminal device can send a deregistration request message to the access network device as a second user identity, or in other words, the terminal device sends a deregistration request message to the access network device through the second user identity, and the deregistration request message carries the identifier of the first user identity, and the deregistration request message is used to request the first user identity to be deregistered in the first network.

[0233] Furthermore, after receiving the deregistration request message, the access network device may pass the message through to the core network device that manages the second user identity. Optionally, when the core network device that manages the first user identity and the core network device that manages the second user identity are the same, the core network device directly completes the relevant deregistration process for the first user identity; optionally, when the core network device that manages the first user identity and the core network device that manages the second user identity are not the same but can communicate with each other, the core network device that manages the second user identity will forward the deregistration request message to the core network device that manages the first user identity, and the core network device completes the relevant deregistration process for the first user identity.

[0234] According to the method 300 provided by the present application, when the first user identity in the terminal device needs to deregister in the first network, a deregistration request message for the first user identity can be sent to the access network device through the second user identity to initiate the deregistration process of the first user identity to the first network, and inform the first network that the first user identity is about to leave. Through the above settings, invalid paging of the first user identity by the first network can be avoided, thereby saving air interface resources and power of the access network device.

[0235] Optionally, the first network may be any one of a public network, a non-independent private network, a non-terrestrial network, and an independent private network.

[0236] The access network device provides services for the second user identity, or in other words, the access network device is an access network device to which a service cell of the second user identity belongs.

[0237] Optionally, before the terminal device sends a deregistration request message to the access network device as the second user identity, that is, before step 320, the second user identity may be in an idle state, a deactivated state, or a connected state, which is not limited in this application.

[0238] For example, the second user identity may be in an idle state. In this case, before step 320, the second user identity needs to establish an RRC connection with the access network device.

[0239] For another example, the second user identity may be in a deactivated state. In this case, before step 320, the second user identity needs to restore the RRC connection with the access network device first.

[0240] Optionally, the access network device may belong to the first network, that is, the second user identity is a user in the first network. In other words, the first user identity and the second user identity may belong to users in the same network, for example, the first user identity and the second user identity belong to the same operator.

[0241] Optionally, the access network device may also belong to a third network, that is, the second user identity is a user in the third network. In other words, the first user identity and the second user identity may belong to users in different networks. In this case, mobility is supported between the third network and the first network, so that a deregistration process of the first user identity may be initiated to the first network through the third network. The following is an example of supporting mobility between the third network and the first network.

[0242] Optionally, supporting mobility between the third network and the first network may mean that the second user identity can perform cell handover and cell reselection between the third network and the first network.

[0243] Optionally, supporting mobility between the third network and the first network may mean that the third network and the first network share the same core network device (such as sharing the same AMF).

[0244] Optionally, supporting mobility between the third network and the first network may refer to that control plane signaling can be interacted between core network devices of the third network and the first network.

[0245] For example, the first network may be a public network, and the third network may be a non-independent private network that depends on the public network. Alternatively, the first network may be a non-independent private network, and the third network may be a public network that the non-independent private network depends on.

[0246] For another example, the first network and the third network may be two non-independent private networks that rely on the same public network.

[0247] In step 310, the deregistration request message carries the identifier of the first user identity. It is easy to understand that the identifier of the first user identity should be the identifier of the first user identity in the first network.

[0248] Optionally, the identifier of the first user identity may be a 5G-GUTI. The 5G-GUTI consists of two parts: a GUAMI and a 5G-S-TMSI.

[0249] In step 320, after receiving the deregistration request message, the access network device (specifically, the access network device of the second user identity) finds the core network device registered with the first user identity according to the GUAMI therein, and the core network device stores the context information of the first user identity. At this time, the access network device forwards the deregistration request message to the found core network device.

[0250] Optionally, the core network device may be an AMF.

[0251] Optionally, the deregistration request message may be transmitted via a NAS layer, that is, the second user identity transparently transmits the deregistration request message to the core network device via the access network device.

[0252] In step 310, the terminal device determines that the first user identity needs to be deregistered in the first network. The present application does not limit how the terminal device determines that the first user needs to be deregistered in the first network, or the reason why the first user identity needs to be deregistered in the first network.

[0253] As a possible implementation, the terminal device determines that the first user identity residing in the first network needs to enter the second network through network selection. At this time, the terminal device can determine that the first user identity needs to be deregistered in the first network.

[0254] That is to say, when the first user identity residing in the first network determines that it needs to leave the first network and enters the second network through network selection, the terminal device can determine that the first user identity needs to be de-registered in the first network, thereby informing the first network that the first user identity is about to leave, avoiding invalid paging of the first user identity by the first network, and thus saving air interface resources and power of access network equipment.

[0255] Optionally, the first user identity can reside in the first network in an RRC idle state or an RRC deactivated state. At this time, the terminal device can support a dual-SIM dual-standby mode, that is, the first user identity and the second user identity share a set of transceivers, and the second user identity maintains an RRC connection with the access network device through the transceiver.

[0256] Optionally, the terminal device may also support a dual-card dual-activation mode, where the first user identity and the second user identity have their own transceivers. In this case, the second user identity maintains an RRC connection with the access network device through its own transceiver. This application does not limit this.

[0257] Optionally, the terminal device may perform the above step 320 after the first user identity enters the second network. Through the above settings, the first user identity may enter the second network faster.

[0258] Optionally, the terminal device may also execute the above step 320 first, and then execute relevant steps of entering the second network as the first user, which is not limited in the present application.

[0259] In the embodiment of the present application, the first network and the second network are two different networks, and the types of the first network and the second network can be the same or different, and the present application does not limit this. For example, the first network can be any one of a public network, an independent private network, a non-independent private network, a non-terrestrial network, etc., and the second network can also be any one of a public network, an independent private network, a non-independent private network, a non-terrestrial network, etc.

[0260] The standards of the first network and the second network may be the same or different, and this application does not limit this. For example, the standards may include a 5G system, an LTE system, a WCDMA system, a code division multiple access CDMA system, and a GSM system.

[0261] In the embodiment of the present application, mobility may or may not be supported between the first network and the second network, and the present application does not limit this.

[0262] For example, the first network may be a public network, and the second network may be an independent private network. Alternatively, the first network may be an independent private network, and the second network may be a public network.

[0263] As another possible implementation, the terminal device may support a dual-card dual-activation mode, where the first user identity and the second user identity have their own transceivers. When the terminal device determines that the transceiver corresponding to the first user identity fails and cannot be used, the terminal device may determine that the first user identity needs to be deregistered in the first network.

[0264] As another possible implementation, in some possible scenarios, for example, when the terminal device determines that it is about to shut down, the terminal device may determine that the first user identity needs to be deregistered in the first network. At this time, the deregistration request message may also carry an identifier of the second user identity, and the deregistration request message is also used to request the deregistration of the second user identity.

[0265] Optionally, according to the above analysis, the second user identity may belong to a user in the first network or the third network, that is, the deregistration request message is also used to request to deregister the second user identity with the first network or the third network.

[0266] Optionally, the terminal device can support N (N is an integer greater than 2) user identities. In this case, the deregistration request message can request to deregister the N user identities at the same time. The deregistration request message can include the identifiers of the N user identities, which is not limited in this application.

[0267] Optionally, the deregistration request message also includes deregistration type indication information, and the deregistration type information may indicate that the reason for the terminal device to deregister is that it is turned off, has gone to another network, etc.

[0268] For example, the deregistration type information may indicate that the first user identity has gone to an independent private network, a non-independent private network or a public network, or a non-terrestrial network (in this case, the type of the second network is an independent private network, a non-independent private network or a public network, or a non-terrestrial network).

[0269] For another example, the deregistration type information may indicate that the terminal device has gone to the second network.

[0270] Optionally, the deregistration request message may further include access type indication information, where the access type indication information is used to indicate in which network the deregistration request message is applied.

[0271] For example, the type of the first network can be any one of an independent private network, a non-independent private network, a public network, a non-terrestrial network, etc. The deregistration type information can indicate that the deregistration request message is applied in an independent private network, a non-independent private network, a public network, a non-terrestrial network, etc.

[0272] For another example, the access type indication information is used to indicate that the deregistration request message is applied in the first network.

[0273] Optionally, the method 300 provided in the embodiment of the present application may further include steps 340 and 350.

[0274] In step 340, the core network device sends a deregistration acceptance message to the access network device, where the deregistration acceptance message includes an identifier of the first user identity.

[0275] Accordingly, in step 340, the access network device receives a deregistration acceptance message sent by the core network device.

[0276] In step 350, the access network device sends the deregistration acceptance message to the second user identity of the terminal device.

[0277] Accordingly, in step 350, the terminal device receives a deregistration acceptance message sent by the access network device.

[0278] Specifically, the core network device receives the deregistration request message, and after completing the relevant deregistration procedure on the core network side, sends a deregistration acceptance message to the access network device.

[0279] The access network device forwards the deregistration acceptance message to the second user identity of the terminal device. After receiving the deregistration acceptance message, the terminal device determines that the deregistration request of the first user identity is received because the deregistration acceptance message includes the identifier of the first user identity, releases the signal connection between the first user identity and the network side, and completes the deregistration process of the first user identity. At this time, the first user identity has almost no context on the core network device side (except for a small amount of information for facilitating authentication), and it can be simply considered that the first user identity no longer exists in this network.

[0280] According to the above analysis, the deregistration request message can request deregistration of multiple user identities (for example, the aforementioned N), and the deregistration acceptance message can be sent according to different situations for whether the deregistration request of each user identity is accepted. For example, a total of S deregistration requests of the N user identities are accepted (S is an integer greater than or equal to 1 and less than or equal to N).

[0281] Optionally, for S deregistration acceptance user identities, S deregistration acceptance messages may be used to indicate to the terminal device, each deregistration acceptance message carrying an identifier of a user identity.

[0282] Optionally, for the S user identities that have been accepted for deregistration, the terminal device may be instructed via a deregistration acceptance message, where the deregistration acceptance message carries the identifiers of the S user identities.

[0283] It should be understood that Figure 8 In the method 300 shown, the terminal device supports the first user identity and the second user identity, and the second user identity initiates a deregistration request for the first user identity. Similarly, in other implementations, the first user identity may also belong to other terminal devices, that is, a deregistration process may also be initiated by one terminal device to another terminal device, and this application does not limit this, and the above situation should also be included in the protection scope of this application.

[0284] Combination of the above Figures 1 to 8 The communication method of the embodiment of the present application is described in detail. Figures 9 to 12 , describes in detail the device of the embodiment of the present application. It should be understood that Figures 9 to 12 The device shown can achieve Figure 5 , 6 Or one or more steps in the method flow shown in 8. To avoid repetition, they will not be described in detail here.

[0285] Fig. 9 is a schematic block diagram of a communication device 500 provided in an embodiment of the present application. Fig. 9 As shown, the device 500 includes: a processing unit 510 and a transceiver unit 520.

[0286] The processing unit 510 is configured to determine that the communication device 500 residing in the first network in the radio resource control RRC idle state or the RRC deactivated state needs to enter the second network through network selection;

[0287] The processing unit 510 is further configured to control the communication device 500 to enter an RRC connected state;

[0288] The processing unit 510 is further configured to initiate a deregistration process to the first network through the transceiver unit 520.

[0289] Optionally, the processing unit 510 is further configured to control the communication device 500 to connect to a first cell, where the first cell is a cell of a first network where the communication device 500 currently resides, or the first cell is another cell of the first network.

[0290] As another implementation, the processing unit 510 is configured to determine that the first user identity needs to be deregistered in the first network, and the communication device 500 supports the first user identity and the second user identity;

[0291] The transceiver unit 520 is used to send a deregistration request message to the access network device as a second user identity, where the deregistration request message carries an identifier of the first user identity, and is used to request the first user identity to deregister in the first network.

[0292] Optionally, the access network device belongs to the first network, or the access network device belongs to a third network, and mobility is supported between the third network and the first network.

[0293] Optionally, the deregistration request message further carries an identifier of the second user identity, and the deregistration request message is further used to request deregistration of the second user identity.

[0294] Optionally, the transceiver unit 520 is further configured to receive a deregistration acceptance message sent by the access network device as the second user, where the deregistration acceptance message carries an identifier of the first user identity.

[0295] Optionally, the processing unit 510 is further configured to determine that the first user identity residing in the first network needs to enter the second network through network selection.

[0296] Specifically, the communication device 500 may correspond to the terminal device in the communication method 200 or 300 according to the embodiment of the present application, or a chip configured in the terminal device. The communication device 500 may include a Figure 5 , 6 Communication method 200 or Figure 8The units of the method executed by the terminal device of the communication method 300 in the communication device 500 are respectively for implementing Figure 5 , 6 Communication method 200 or Figure 8 The corresponding process of the communication method 300 and the specific process of each unit executing the above corresponding steps have been described in detail in methods 200 and 300, and will not be repeated here for the sake of brevity.

[0297] The communication device 500 may be a smart terminal or a wearable device, etc., and the transceiver unit 520 may be a transceiver or a transceiver circuit. Optionally, the transceiver may also be an input / output circuit or an interface.

[0298] The communication device 500 may also be a chip. The transceiver unit 520 may be an input / output circuit or an interface of the chip.

[0299] In a possible implementation, the communication device 500 may be a terminal device 50, wherein the function of the generating unit 510 may be implemented by the processor 502 in the terminal device 50, and the function of the sending unit 520 may be implemented by the transceiver 501 (i.e., the control circuit and the antenna together) of the terminal device. Fig.10 The structure of the terminal device of the embodiment of the present application is introduced.

[0300] Fig.10 is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application. The terminal device can be applied to Figure 1 In the system shown, the functions of the terminal device in the above method embodiment are executed. Fig.10 Only the main components of the terminal device are shown. Fig.10 As shown, the terminal device 50 includes a processor, a memory, a control circuit, an antenna, and an input-output device. The processor is mainly used to process the communication protocol and the communication data, and to control the entire terminal device, execute the software program, and process the data of the software program, for example, to support the terminal device to perform the actions described in the above method embodiment. The memory is mainly used to store software programs and data. The control circuit is mainly used for converting baseband signals and radio frequency signals and processing radio frequency signals. The control circuit and the antenna together can also be called a transceiver, which is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input-output devices, such as touch screens, display screens, keyboards, etc., are mainly used to receive data input by users and output data to users.

[0301] When the terminal device is turned on, the processor can read the software program in the memory, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the RF circuit. The RF circuit performs RF processing on the baseband signal and then sends the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the terminal device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data.

[0302] Those skilled in the art will appreciate that for ease of description, Fig.10 Only one memory and one processor are shown. In an actual terminal device, there may be multiple processors and multiple memories. The memory may also be referred to as a storage medium or a storage device, etc. The memory may be a storage element on the same chip as the processor, i.e., an on-chip storage element, or an independent storage element, which is not limited in the embodiments of the present application.

[0303] As an optional implementation, the terminal device may include a baseband processor and a central processing unit, the baseband processor is mainly used to process the communication protocol and communication data, and the central processing unit is mainly used to control the entire terminal device, execute software programs, and process software program data. Fig.10 The processor in the can integrate the functions of the baseband processor and the central processing unit. Those skilled in the art can understand that the baseband processor and the central processing unit can also be independent processors, which are interconnected through technologies such as buses. Those skilled in the art can understand that the terminal device can include multiple baseband processors to adapt to different network standards, and the terminal device can include multiple central processing units to enhance its processing capabilities. The various components of the terminal device can be connected through various buses. The baseband processor can also be expressed as a baseband processing circuit or a baseband processing chip. The central processing unit can also be expressed as a central processing circuit or a central processing chip. The function of processing the communication protocol and communication data can be built into the processor, or it can be stored in the memory in the form of a software program, and the processor executes the software program to realize the baseband processing function.

[0304] In the embodiment of the present application, the antenna and the control circuit with transceiver functions can be regarded as the transceiver unit 501 of the terminal device 50, for example, used to support the terminal device to perform the receiving function and the sending function. The processor 502 with the processing function can be regarded as the processing unit 502 of the terminal device 50. Fig.10As shown, the terminal device 50 includes a transceiver unit 501 and a processing unit 502. The transceiver unit may also be referred to as a transceiver, a transceiver, a transceiver device, etc. Optionally, a device for implementing a receiving function in the transceiver unit 501 may be regarded as a receiving unit, and a device for implementing a sending function in the transceiver unit 501 may be regarded as a sending unit, that is, the transceiver unit 501 includes a receiving unit and a sending unit, the receiving unit may also be referred to as a receiver, an input port, a receiving circuit, etc., and the sending unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0305] The processor 502 may be used to execute the instructions stored in the memory to control the transceiver unit 501 to receive signals and / or send signals, thereby completing the functions of the terminal device in the above method embodiment. The processor 502 also includes an interface to implement the input / output function of the signal. As an implementation method, the functions of the transceiver unit 501 may be implemented by a transceiver circuit or a dedicated chip for transceiver.

[0306] Fig.11 600 is a schematic block diagram of a communication device 600 provided in an embodiment of the present application. Fig.11 As shown, the device 600 includes: a receiving unit 610 and a sending unit 620.

[0307] A receiving unit 610 is configured to receive a deregistration request message sent by a terminal device as a second user, where the deregistration request message carries an identifier of a first user identity, and the deregistration request message is used to request the first user identity to deregister in the first network;

[0308] The sending unit 620 is used to send the deregistration request message to the core network device.

[0309] Optionally, the communication device 600 belongs to the first network, or the communication device 600 belongs to a third network, and mobility is supported between the third network and the first network.

[0310] Optionally, the deregistration request message further carries an identifier of the second user identity, and the deregistration request message is further used to request deregistration of the second user identity.

[0311] Optionally, the sending unit 620 is further configured to send a deregistration acceptance message to the second user identity of the terminal device, where the deregistration acceptance message carries an identifier of the first user identity.

[0312] Specifically, the communication device 600 may correspond to the access network device in the communication method 200 or 300 according to the embodiment of the present application, or a chip configured in the access network device. The communication device 600 may include a Figure 5 , 6 Communication method 200 or Figure 8The units of the method performed by the access network device of the communication method 300. In addition, the units in the communication device 600 and the above-mentioned other operations and / or functions are respectively for implementing Figure 5 , 6 Communication method 200 or Figure 8 The corresponding process of the communication method 300 and the specific process of each unit executing the above corresponding steps have been described in detail in methods 200 and 300, and will not be repeated here for the sake of brevity.

[0313] In a possible implementation, the communication device 600 may be a base station, a gNB or a TRP, a DU, a CU, a CU-CP (control plane) or a CU-UP (user plane), etc. The receiving unit 610 and the sending unit 620 may be a transceiver or a transceiver circuit. Optionally, the transceiver may also be an input / output circuit or an interface.

[0314] The communication device 600 may also be a chip. The receiving unit 610 and the sending unit 620 may be input / output circuits or interfaces of the chip.

[0315] In a possible implementation, the communication device 600 may be an access network device, such as a base station 60 hereinafter, wherein the functions of the receiving unit 610 and the sending unit 620 may be implemented by an RRU 601 of the base station 60. Fig.12 The structure of the network device of the embodiment of the present application is introduced.

[0316] Fig.12 Schematic diagram of the structure of an access network device in an embodiment of the present application, such as a schematic diagram of the structure of a base station. Fig.12 As shown, the base station can be applied to Figure 1 In the system shown, the functions of the access network device in the above method embodiment are performed. The base station 60 may include one or more radio frequency units, such as a remote radio unit (RRU) 601 and one or more baseband units (BBU) (also referred to as digital units, digital units, DU) 602. The RRU 601 may be referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., and may include at least one antenna 6011 and a radio frequency unit 6012. The RRU 601 part is mainly used for the transmission and reception of radio frequency signals and the conversion of radio frequency signals and baseband signals, for example, for sending the signaling message described in the above embodiment to the terminal device. The BBU 602 part is mainly used for baseband processing, controlling the base station, etc. The RRU 601 and the BBU 602 may be physically arranged together, or they may be physically separated, that is, a distributed base station.

[0317] The BBU 602 is the control center of the base station, which can also be called a processing unit, and is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulation, spread spectrum, etc. For example, the BBU (processing unit) 602 can be used to control the base station to execute the operation process of the network device in the above method embodiment.

[0318] In one example, the BBU 602 may be composed of one or more boards, and the multiple boards may jointly support a wireless access network with a single access indication (such as an LTE network), or may respectively support wireless access networks with different access standards (such as an LTE network, a 5G network, or other networks). The BBU 602 also includes a memory 6021 and a processor 6022, and the memory 6021 is used to store necessary instructions and data. For example, the memory 6021 stores the correspondence between the codebook index and the precoding matrix in the above embodiment. The processor 6022 is used to control the base station to perform necessary actions, such as controlling the base station to execute the operation flow of the network device in the above method embodiment. The memory 6021 and the processor 6022 can serve one or more boards. That is, a memory and a processor may be separately set on each board. It is also possible that multiple boards share the same memory and processor. In addition, necessary circuits may be set on each board.

[0319] It should be understood that the processor in the embodiment of the present application may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0320] It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0321] According to the method provided in the embodiment of the present application, the present application also provides a computer program product, which includes: a computer program code, when the computer program code is run on a computer, the computer executes Figure 5 , 6 or Figure 8 A method according to any one of the embodiments shown.

[0322] According to the method provided in the embodiment of the present application, the present application also provides a computer-readable medium, which stores a program code, and when the program code is run on a computer, the computer executes Figure 5 , 6 or Figure 8 A method according to any one of the embodiments shown.

[0323] According to the method provided in the embodiment of the present application, the present application also provides a system, which includes one or more terminal devices, one or more access network devices, and one or more core network devices as mentioned above.

[0324] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0325] For ease of understanding, the terms involved in the process of introducing the solution of this application are explained below.

[0326] In the embodiments of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the "indication information" in the foregoing text) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein the other information has an association relationship with the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can also be achieved by means of the arrangement order of each information agreed in advance (such as specified by the protocol), thereby reducing the indication overhead to a certain extent.

[0327] In the embodiments of the present application, various terms and English abbreviations, such as public network (PLMN), non-standalone private network (CAG), standalone private network (SNPN), radio resource control (RRC), access and mobility management function (AMF), etc., are all illustrative examples given for the convenience of description and shall not constitute any limitation to the present application. The present application does not exclude the possibility of defining other terms that can achieve the same or similar functions in existing or future protocols.

[0328] In the embodiments of the present application, "first", "second" and various numbers are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application. For example, to distinguish different indication information.

[0329] The “communication protocol” involved in the embodiments of the present application may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, an NR protocol, and related protocols used in future communication systems, and the present application does not limit this.

[0330] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0331] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0332] In various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0333] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0334] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0335] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0336] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0337] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0338] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

Claims

1. A communication method, characterized in that: include: The terminal device determines that the first user identity needs to be deregistered in the first network, and the terminal device supports the first user identity and the second user identity; The terminal device sends a deregistration request message to the access network device as the second user identity, where the deregistration request message carries an identifier of the first user identity, and the deregistration request message is used to request the first user identity to be deregistered in the first network; The access network device belongs to a third network, and mobility is supported between the third network and the first network.

2. The method according to claim 1, characterized in that: The deregistration request message also carries the identifier of the second user identity, and the deregistration request message is also used to request deregistration of the second user identity.

3. The method according to claim 1, characterized in that The method further comprises: The terminal device receives a deregistration acceptance message sent by the access network device as the second user identity, and the deregistration acceptance message carries the identifier of the first user identity.

4. The method according to claim 1, characterized in that The terminal device determines that the first user identity needs to be deregistered in the first network, including: The terminal device determines that the first user identity residing in the first network needs to enter the second network through network selection.

5. A communication method, characterized in that: include: The access network device receives a deregistration request message sent by the terminal device as a second user, where the deregistration request message carries an identifier of the first user identity, and the deregistration request message is used to request the first user identity to deregister in the first network; The access network device sends the deregistration request message to the core network device; The access network device belongs to a third network, and mobility is supported between the third network and the first network.

6. The method according to claim 5, characterized in that The deregistration request message also carries the identifier of the second user identity, and the deregistration request message is also used to request deregistration of the second user identity.

7. The method according to claim 5, characterized in that The method further comprises: The access network device sends a deregistration acceptance message to the second user identity of the terminal device, and the deregistration acceptance message carries the identifier of the first user identity.

8. A communication device, characterized in that: include: a processing unit, configured to determine that the first user identity needs to be deregistered in the first network, the communication device supporting the first user identity and the second user identity; a transceiver unit, configured to send a deregistration request message to an access network device as the second user identity, wherein the deregistration request message carries an identifier of the first user identity, and the deregistration request message is used to request the first user identity to be deregistered in the first network; The access network device belongs to a third network, and mobility is supported between the third network and the first network.

9. The communication device according to claim 8, characterized in that: The deregistration request message also carries the identifier of the second user identity, and the deregistration request message is also used to request deregistration of the second user identity.

10. The communication device according to claim 8, characterized in that: The transceiver unit is further configured to receive a deregistration acceptance message sent by the access network device as the second user, wherein the deregistration acceptance message carries an identifier of the first user identity.

11. The communication device according to claim 8, characterized in that: The processing unit is further configured to determine that the first user identity residing in the first network needs to enter a second network through network selection.

12. A communication device, characterized in that: include: A receiving unit, configured to receive a deregistration request message sent by a terminal device as a second user, wherein the deregistration request message carries an identifier of a first user identity, and the deregistration request message is used to request the first user identity to deregister in the first network; A sending unit, configured to send the deregistration request message to a core network device; The communication device belongs to a third network, and mobility is supported between the third network and the first network.

13. The communication device according to claim 12, characterized in that: The deregistration request message also carries the identifier of the second user identity, and the deregistration request message is also used to request deregistration of the second user identity.

14. The communication device according to claim 12, characterized in that: The sending unit is further configured to send a deregistration acceptance message to the second user identity of the terminal device, wherein the deregistration acceptance message carries an identifier of the first user identity.

15. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 7.

16. A chip system, characterized in that: It comprises: a processor, used to call and run a computer program from a memory, so that a communication device equipped with the chip system executes the method as claimed in any one of claims 1 to 7.

17. A communication device, characterized in that: The system comprises at least one processor, wherein the at least one processor is configured to be coupled to a memory, read and execute instructions in the memory, so as to implement the method according to any one of claims 1 to 7.

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