Communication method and device

Abstract

The invention relates to a communication method and device. And the first device receives an RRC release message from the first cell, the RRC release message being used for releasing the first device to an RRC non-connected state to receive the multicast service, and the RRC release message also indicating the first frequency. The first device enters an RRC non-connected state based on the RRC release message. If the first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, the first device resides in the first candidate cell. According to the embodiment of the invention, the effective range of the frequency is set, for example, the cell in the effective range may provide the multicast service in the RRC non-connection state. If the first candidate cell is included in the effective range, it is indicated that the first candidate cell may provide the multicast service in the RRC non-connection state, the first device may reside in the first candidate cell, and the probability that the first device successfully receives the multicast service in the RRC non-connection state in a newly resident cell is improved.

Description

Technical Field

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

[0002] Multicast and broadcast service (MBS) is a service for multiple user equipment (UE), such as live broadcast service, public safety service, batch software update service, etc. In the new radio (NR) system, MBS includes broadcast service and multicast service, among which multicast service is also called multicast service. UE can receive multicast service in radio resource control (RRC) connected state. However, when the number of users receiving multicast service in a cell is too large, it may exceed the number of RRC connected users that the cell can accommodate, which may cause congestion and other phenomena. In order to alleviate network congestion, it is currently proposed to support UE joining a multicast session to receive multicast service in RRC inactive state. For example, a cell releases the UE to RRC inactive state through an RRC release message, and the RRC release message may indicate the cell reselection priority, which is a dedicated priority for cell reselection. The UE may then perform cell reselection based on the cell reselection priority to receive the multicast service in the RRC non-connected state.

[0003] However, there may be problems with this approach. For example, cell 1 of the UE at frequency 1 is released to the RRC non-connected state, and the RRC release message sent by cell 1 to the UE indicates frequency 2 for receiving multicast services in the RRC non-connected state. The UE can then reselect to cell 2 at frequency 2 to receive multicast services in cell 2. Although cell 2 is a cell at frequency 2, it may not provide multicast services in the RRC non-activated state, that is, at frequency 2, other cells except cell 2 may provide multicast services in the RRC non-activated state, but cell 2 does not. It can be seen that the UE may reselect an inappropriate cell through the current mechanism, resulting in the UE being unable to receive multicast services in the RRC non-connected state. Summary of the invention

[0004] Embodiments of the present application provide a communication method and apparatus for improving the probability of a UE successfully receiving a multicast service in an RRC non-connected state.

[0005] In a first aspect, a communication method is provided, which can be performed by a first device. The first device is, for example, a terminal device, or other device including the functions of a terminal device, or a chip system (or, chip) or other functional module, which can realize the function of the first device, and the chip system or functional module is, for example, arranged in the terminal device. The method includes: receiving an RRC release message from a first cell, the RRC release message is used to release the first device to an RRC non-connected state to receive a multicast service, and the RRC release message is also used to indicate a first frequency; entering the RRC non-connected state based on the RRC release message; if a first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, residing in the first candidate cell.

[0006] The embodiment of the present application sets the effective range of the frequency. For example, the cell within the effective range may provide multicast services in the RRC non-connected state. Then, the RRC release message indicates the first frequency. When the first device performs cell reselection or cell selection, if the first candidate cell is selected, it does not directly reside in the first candidate cell, but determines whether the first candidate cell is included in the effective range corresponding to the first frequency. For example, if it is included in the effective range, it indicates that the first candidate cell may provide multicast services in the RRC non-connected state, then the first device can reside in the first candidate cell, thereby increasing the probability that the first device successfully receives the multicast service in the RRC non-connected state in the newly resided cell. Optionally, if the first candidate cell is not included in the effective range, the first device may not reside in the first candidate cell. For example, the first device may continue to select other candidate cells to receive multicast services in the RRC non-connected state as much as possible, rather than entering the RRC connected state in the first candidate cell to receive multicast data, thereby reducing the condition of entering the RRC connected state and reducing the congestion of the cell.

[0007] In an optional implementation, the method further includes: receiving a first multicast service in the first candidate cell in the RRC non-connected state. If the first candidate cell is included in the effective range corresponding to the first frequency, the first candidate cell is a cell that is more likely to provide a multicast service in the RRC non-connected state. If the first device resides in the first candidate cell, it can receive a multicast service in the first candidate cell in the RRC non-connected state, so that the first device does not need to enter the RRC connected state, which reduces the power consumption caused by entering the RRC connected state and also reduces the congestion level of the cell.

[0008] In an optional implementation, the RRC release message is also used to indicate the priority of the first frequency, and the priority of the first frequency is used by the first device to reselect a cell for receiving a multicast service in the RRC non-connected state. When the first device reselects a cell, the priority of the first frequency can be used. For example, the first device can set the priority of the first frequency to the highest priority during the reselection process, so that the first device can give priority to the cell under the first frequency to increase the probability of the first device receiving the multicast service.

[0009] In an optional implementation, the effective range is used to indicate the cell or area that provides the multicast service in the RRC non-connected state at the first frequency. For example, the effective range of the first frequency (or the effective range of a certain frequency A in the first frequency) may include (or indicate) one or more of the following: information (such as cell identifiers) of some or all cells under the first frequency (or frequency A), one or more radio access network-area codes (RNA) corresponding to the first frequency (or frequency A), or one or more tracking area codes (tracking area code) corresponding to the first frequency (or frequency A). Alternatively, the effective range can also indicate the cell or area that provides the multicast service in the RRC non-connected state at the first frequency through other information, and there is no limitation on this.

[0010] In an optional implementation, the RRC release message is also used to indicate the effective range. The effective range of the first frequency can be indicated by the RRC release message, or can also be indicated by other messages from the network device, or can also be predefined by the protocol, or preconfigured in the first device.

[0011] In an optional implementation, the method further includes: setting the first frequency as the frequency with the highest priority. For example, during the cell reselection process, the first device may set the first frequency as the frequency with the highest priority, or set the priority of the first frequency to the highest priority, so that the first device can preferentially select the candidate cell under the first frequency to increase the probability of the first device receiving the multicast service.

[0012] In an optional implementation, if the first candidate cell at the first frequency is included in the effective range corresponding to the first frequency, before residing in the first candidate cell, the method further includes: measuring the first candidate cell; and determining that the first candidate cell meets the cell reselection condition according to the measurement result. The first device can first determine that the first candidate cell meets the cell reselection condition, which indicates that the first candidate cell can reside, and then the first device determines whether the first candidate cell is within the effective range of the first frequency, which is conducive to compatibility with the traditional cell reselection process.

[0013] In an optional implementation, if the first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, before residing in the first candidate cell, the method further includes: measuring the first candidate cell. If the first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, residing in the first candidate cell includes: if the first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, determining whether the first candidate cell meets the cell reselection condition according to the measurement result; if the first candidate cell meets the cell reselection condition, residing in the first candidate cell. In this way, the first device can first determine whether the first candidate cell is included in the effective range corresponding to the first frequency. If the first candidate cell is included in the effective range corresponding to the first frequency, the first device can further determine whether the first candidate cell meets the cell reselection condition. If the first candidate cell is not included in the effective range corresponding to the first frequency, the first device does not need to determine whether the first candidate cell meets the cell reselection condition. For example, the first device can continue to determine the next candidate cell. It can be seen that in this way, the first device can reduce the determination process of the candidate cell, save the power consumption of the first device, and improve the efficiency of cell reselection.

[0014] In an optional implementation, if the first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, residing in the first candidate cell includes: if the first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, measuring the first candidate cell; if it is determined according to the measurement result that the first candidate cell meets the cell reselection condition, residing in the first candidate cell. In this way, the first device can first determine whether the first candidate cell is included in the effective range corresponding to the first frequency. If the first candidate cell is included in the effective range corresponding to the first frequency, the first device can further perform measurement and other processing processes on the first candidate cell. If the first candidate cell is not included in the effective range corresponding to the first frequency, the first device does not need to measure the first candidate cell, for example, the first device can continue to determine the next candidate cell. In this way, the determination process of the first device for the candidate cell can be reduced to a greater extent, the power consumption of the first device can be saved, and the efficiency of cell reselection can be improved.

[0015] In an optional implementation, the method further includes: if the first candidate cell at the first frequency is not included in the effective range corresponding to the first frequency, not residing in the first candidate cell. If the first candidate cell is not included in the effective range, the first device may not reside in the first candidate cell. For example, the first device may continue to select other candidate cells to receive multicast services in the RRC non-connected state as much as possible, rather than entering the RRC connected state in the first candidate cell to receive multicast data, thereby reducing the situation of entering the RRC connected state and alleviating the congestion of the cell.

[0016] In an optional implementation, the method further includes: if the number of times the candidate cell is selected is greater than or equal to a first threshold, staying in the candidate cell selected last time. During a cell reselection process, if a qualified cell is not selected, the first device may enter an infinite loop, that is, it is always in a cell reselection state and may not be able to communicate normally. In order to reduce the probability of the first device entering an infinite loop, the embodiment of the present application can set a first threshold so that the first device can exit the cell reselection process in time to communicate.

[0017] In a second aspect, another communication method is provided, which can be performed by a first device. The first device is, for example, a terminal device, or other device including the functions of a terminal device, or a chip system (or, chip) or other functional module, which can realize the functions of the first device, and the chip system or functional module is, for example, arranged in the terminal device. The method includes: determining that the first candidate cell does not provide a multicast service in an RRC non-connected state; receiving a second message from the first candidate cell, the second message is used to indicate a second frequency; if the second frequency includes the frequency of the first candidate cell, entering an RRC connected state in the first candidate cell.

[0018] In the embodiment of the present application, although the first candidate cell does not currently provide multicast services in the RRC non-connected state, it can be known through the judgment process of the first device that the first candidate cell is likely to provide multicast services in the RRC connected state. Therefore, the first device can reside in the first candidate cell and enter the RRC connected state in the first candidate cell, so that after entering the RRC connected state, it can have a greater probability of receiving multicast services, thereby improving the success rate of the first device receiving multicast services. If the first device determines that the first candidate cell does not currently provide multicast services in the RRC non-connected state without making any judgments, but directly enters the RRC connected state, then if the frequency of the first candidate cell is not included in the frequencies that may provide multicast services, even if the first device enters the RRC connected state, it may not be able to receive the multicast service. It can be seen that the method provided in the embodiment of the present application can increase the probability of the first device receiving multicast services.

[0019] In an optional implementation, the second message is also used to indicate the priority of the second frequency, and the priority of the second frequency is used by the first device to perform cell reselection for receiving multicast services in the RRC non-connected state. When the first device performs cell reselection, the priority of the first frequency can be used. For example, the first device can set the priority of the first frequency to the highest priority in the reselection process, so that the first device can give priority to the cell under the first frequency to increase the probability of the first device receiving the multicast service.

[0020] In an optional implementation, the method further includes: if the second frequency does not include the frequency corresponding to the first candidate cell, not residing in the first candidate cell. If the frequency of the first candidate cell is not included in the second frequency, even if the first device enters the RRC connection state, it may not be able to receive the multicast service, so the first device may not reside in the first candidate cell, for example, the first device may continue to identify the next candidate cell. Through the method provided in the embodiment of the present application, the probability of the first device receiving the multicast service can be increased.

[0021] In an optional implementation, if the second frequency includes the frequency of the first candidate cell, entering the RRC connection state in the first candidate cell includes: if the first frequency and the second frequency have an intersection, and the intersection includes the frequency of the first candidate cell, entering the RRC connection state in the first candidate cell, the first frequency is the frequency indicated by the first message received in the source cell. The first frequency is a frequency determined by the first cell or the second cell to provide a multicast service in the RRC non-connected state, and the multicast service provided by the cell under the first frequency is likely to be a multicast service that the first device is interested in or is relatively important to the first device. Then if the first frequency and the second frequency have an intersection, the service provided by the cell under the frequency corresponding to the intersection may be a multicast service that the first device is interested in or is relatively important to the first device. If the intersection includes the frequency of the first candidate cell, it indicates that the first candidate cell may provide these multicast services. In this case, although the first candidate cell does not currently provide a multicast service in the RRC non-connected state, the first candidate cell may provide a multicast service in the RRC connection state. Therefore, the first device can reside in the first candidate cell and enter the RRC connection state in the first candidate cell, so that after entering the RRC connection state, it can receive multicast services with a greater probability, thereby improving the success rate of UE receiving multicast services, and also making the first device more likely to obtain multicast services that the first device is interested in or are more important to the first device.

[0022] In an optional implementation, the method further includes: if the number of times a candidate cell is selected is greater than or equal to a first threshold, the last selected candidate cell enters an RRC connection state. During a cell reselection process, if a qualified cell is not selected, the first device may enter an infinite loop, that is, it is always in a cell reselection state and may not be able to communicate normally. In order to reduce the probability of the first device entering an infinite loop, the embodiment of the present application may set a first threshold so that the first device can exit the cell reselection process in time to communicate.

[0023] In an optional implementation, the first message is an RRC release message or an MCCH message, and the second message is an MCCH message; or, the first message is an RRC release message or a system message, and the second message is a system message. In addition, the first message and / or the second message may also have other implementations, which are not specifically limited.

[0024] In a third aspect, a communication device is provided. The communication device may be the first device described in any one of the first aspect to the second aspect. The communication device has the function of the first device. The first device is, for example, a terminal device, or other device including the function of a terminal device, or a chip system (or, chip) or other functional module, the chip system or functional module can realize the function of the first device, the chip system or functional module is, for example, set in the terminal device. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The transceiver unit can realize the sending function and the receiving function. When the transceiver unit realizes the sending function, it can be called a sending unit (sometimes also referred to as a sending module), and when the transceiver unit realizes the receiving function, it can be called a receiving unit (sometimes also referred to as a receiving module). The sending unit and the receiving unit can be the same functional module, the functional module is called a transceiver unit, the functional module can realize the sending function and the receiving function; or, the sending unit and the receiving unit can be different functional modules, the transceiver unit is a general term for these functional modules.

[0025] In an optional embodiment, the transceiver unit (or, the receiving unit) is used to receive an RRC release message from the first cell, the RRC release message is used to release the first device to the RRC non-connected state to receive multicast services, and the RRC release message is also used to indicate a first frequency; the processing unit is used to enter the RRC non-connected state based on the RRC release message; the processing unit is also used to reside in the first candidate cell if the first candidate cell under the first frequency is included in the effective range corresponding to the first frequency.

[0026] In an optional embodiment, the processing unit is used to determine that the first candidate cell does not provide multicast services in the RRC non-connected state; the transceiver unit (or, the receiving unit) is used to receive a second message from the first candidate cell, and the second message is used to indicate a second frequency; the processing unit is also used to enter the RRC connected state in the first candidate cell if the second frequency includes the frequency of the first candidate cell.

[0027] In an optional embodiment, the communication device also includes a storage unit (sometimes also referred to as a storage module), and the processing unit is used to couple with the storage unit and execute the program or instructions in the storage unit, so that the communication device can perform the function of the first device described in any one of the first to second aspects above.

[0028] In a fourth aspect, a communication device is provided, which may be a terminal device, or a chip or chip system used in a terminal device. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is used to store a computer program, and the processor is coupled to the memory and the communication interface. When the processor reads the computer program or instruction, the communication device executes the method executed by the first device in the above aspects.

[0029] In a fifth aspect, a communication system is provided, comprising a first device, wherein the first device is used to execute the method performed by the first device described in the first aspect or the second aspect. For example, the first device can be implemented by the communication device described in the third aspect or the fourth aspect. Optionally, the communication system may also include other devices or equipment, such as a network device and / or other devices (such as other terminal devices) other than the first device, without limitation.

[0030] In a sixth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium is used to store a computer program or instruction, and when the computer-readable storage medium is executed, the method performed by the first device in the above aspects is implemented.

[0031] According to a seventh aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the methods described in the above aspects to be implemented.

[0032] In an eighth aspect, a chip system is provided, comprising a processor and an interface, wherein the processor is used to call and execute instructions from the interface so that the chip system implements the methods of the above aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of a UE reselecting another cell to receive a multicast service after being released;

[0034] Figure 2 A schematic diagram of a network architecture used in an embodiment of the present application;

[0035] Figure 3 A flow chart of a communication method provided in an embodiment of the present application;

[0036] Figure 4A and Figure 4B A flowchart of two cell reselection processes under the first cell reselection mode provided in an embodiment of the present application;

[0037] Figure 5A and Figure 5B A flowchart of two cell reselection processes under the second cell reselection mode provided in an embodiment of the present application;

[0038] Fig. 6Aand Figure 6B A flowchart of two cell reselection processes under the third cell reselection mode provided in an embodiment of the present application;

[0039] Figure 7 A flowchart of another communication method provided in an embodiment of the present application;

[0040] Figure 8 A schematic diagram of a device provided in an embodiment of the present application;

[0041] Fig. 9 A schematic diagram of another device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0043] In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. For example, A / B means: A or B. "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 means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0044] The ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority or importance of multiple objects. In addition, the numbering of the steps in the various embodiments introduced in the present application is only to distinguish different steps, and is not used to limit the order between the steps. For example, S301 may occur before S302, or may occur after S302, or may occur at the same time as S302.

[0045] Below, some terms or concepts in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0046] In an embodiment of the present application, the terminal device is a device with wireless transceiver functions, which can be a fixed device, a mobile device, a handheld device (such as a mobile phone), a wearable device, a vehicle-mounted device, or a wireless device built into the above devices (for example, a communication module, a modem, or a chip system, etc.). The terminal device is used to connect people, objects, machines, etc., and can be widely used in various scenarios, such as but not limited to the following scenarios: perception scenarios, cellular communications, device-to-device communications (D2D), vehicle to everything (V2X), machine-to-machine / machine-type communications (M2M / MTC), Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, self driving, remote medical, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, drones, robots, indoor commercial scenarios (such as mobile phone screen projection, file sharing, mobile phone to VR glasses video transmission) and other scenarios of terminal devices. When the terminal device is applied to V2X, it can also be called V2X device, for example, smart car (smart car or intelligent car), digital car (digital car), unmanned car (unmanned car or driverless car or pilotless car or automobile), automatic car (self-driving car or autonomous car), pure electric vehicle (pure EV or Battery EV), hybrid electric vehicle (hybrid electric vehicle, HEV), range extended EV (REEV), plug-in hybrid electric vehicle (plug-in HEV, PHEV), new energy vehicle (new energy vehicle), roadside unit (road site unit, RSU). The terminal device can also be a device in D2D communication, such as an electric meter, a water meter, etc.

[0047] In addition, in the embodiments of the present application, the terminal device can also be a terminal device in an IoT system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network that interconnects people and machines and things.

[0048] The various terminal devices introduced above, if located on a vehicle (e.g., placed in a vehicle or installed in a vehicle), can all be considered as vehicle-mounted terminal devices, which are also called on-board units (OBU). The terminal device of the present application can also be an on-board module, on-board module, on-board component, on-board chip or on-board unit built into the vehicle as one or more components or units, and the vehicle can implement the method of the present application through the built-in on-board module, on-board module, on-board component, on-board chip or on-board unit.

[0049] The terminal device may sometimes be referred to as UE, terminal, access station, UE station, remote station, wireless communication device, or user equipment, etc.

[0050] In the embodiment of the present application, the communication device for implementing the function of the terminal device may be a terminal device, or may be a device capable of supporting the terminal device to implement the function, such as a chip system, which may be installed in the terminal device. In the technical solution provided in the embodiment of the present application, the technical solution provided in the embodiment of the present application is described by taking the device for implementing the function of the terminal device as an example, and the terminal device is used as an example. In addition, for the convenience of description, the terminal device is described in the embodiment of the present application by taking the UE as an example.

[0051] The network equipment in the embodiment of the present application, for example, includes access network equipment, and / or core network equipment. The access network equipment is a device with wireless transceiver function, which is used to communicate with the terminal device. The access network equipment includes but is not limited to base stations (base transceiver station (BTS), Node B, evolved node B (eNodeB) / eNB, or next generation node B (gNodeB) / gNB), transceiver points (transmission reception point, TRP), base stations of subsequent evolution of the third generation partnership project (3rd generation partnership project, 3GPP), access nodes in wireless fidelity (Wi-Fi) systems, wireless relay nodes, wireless backhaul nodes, etc. The base station can be: a macro base station, a micro base station, a micro-micro base station, a small station, a relay station, etc. Multiple base stations can support networks with the same access technology, or networks with different access technologies. The base station can include one or more co-station or non-co-station transmission and receiving points. The access network device may also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. The access network device may also be a server, etc. For example, the network device in the V2X technology may be a road side unit (RSU). The following describes the access network device using a base station as an example. The base station can communicate with a terminal device, or it can communicate with the terminal device through a relay station. The terminal device can communicate with multiple base stations in different access technologies. The core network device is used to implement functions such as mobility management, data processing, session management, policy and billing. The names of the devices that implement core network functions in systems with different access technologies may be different, and the embodiments of the present application do not limit this. Taking the fifth generation mobile communication technology (5G) system as an example, the core network equipment includes: access and mobility management function (AMF), session management function (SMF), policy control function (PCF) or user plane function (UPF), etc.

[0052] In the embodiment of the present application, the communication device for realizing the function of the network device may be a network device, or may be a device capable of supporting the network device to realize the function, such as a chip system, which may be installed in the network device. In the technical solution provided in the embodiment of the present application, the technical solution provided in the embodiment of the present application is described by taking the device for realizing the function of the network device as an example that the network device is used as the device.

[0053] When a UE in the RRC non-connected state resides in a cell normally, it can measure the signal quality of the cell and neighboring cells to select a better cell to reside in according to the cell reselection rule. When the UE performs cell reselection, the main process is as follows:

[0054] 1. According to the measurement start standard, measure the current resident cell and neighboring cells (including one or more cells of the same frequency cell, different frequency cell, or different system cell).

[0055] 2. Determine whether the signal quality of the neighboring cell meets the cell reselection conditions.

[0056] 3. If the signal quality of the neighboring cell meets the cell reselection conditions, the cell reselection is initiated and the system message from the new cell is received. If it is determined according to the system message that there is no access restriction, etc., the new cell can be camped. If the signal quality of the neighboring cell does not meet the cell reselection conditions, the current camping cell can continue to stay.

[0057] The neighboring cell measurement process is introduced as follows.

[0058] Neighboring cell measurement considers two parameters: priority (called cell reselection priority) and signal quality of the current cell. The process can be briefly described as follows: For neighboring cells with a higher cell reselection priority than the current cell, measurement must be started unconditionally regardless of how good the signal quality of the current cell is. For neighboring cells with a cell reselection priority less than or equal to the current cell. The UE can measure the signal quality of the current cell and compare the measurement result with the signal quality threshold. If the signal quality of the current cell is greater than or equal to the signal quality threshold, the neighboring cell may not be measured; if the signal quality of the current cell is less than the signal quality threshold, the neighboring cell may be measured.

[0059] According to the above introduction, when the UE performs measurement and cell reselection, the cell reselection priority of the neighboring cell is needed. The cell reselection priority of NR inter-frequency and inter-system is configured by the system message or RRC Release message, or is inherited from the inter-system when performing inter-system reselection. If the cell reselection priority is configured by dedicated signaling (such as RRC Release message), the UE should ignore the cell reselection priority provided in the system message. When the UE performs cell reselection in the same-frequency cell, the cell reselection priority will be ignored, that is, the cell reselection priority of the same-frequency cell is the same.

[0060] For neighboring cell information and cell reselection priority, the UE can obtain it from the system message of the current serving cell. For example, this information is configured by the network side and sent to the UE through cell broadcast. The value range of the cell reselection priority (cellReselectionPriority) parameter is (0-7). The larger the value of this parameter, the higher the cell reselection priority of all cells on the corresponding carrier. In addition, the NR system also configures a cell reselection sub-priority (CellReselectionSubPriority) parameter for each carrier, so that the cell reselection priority of the carrier can be divided at a finer granularity. The value of the cell reselection sub-priority parameter is 0.2 / 0.4 / 0.6 / 0.8.

[0061] The RRC Release message can provide the UE with a dedicated cell reselection priority through the cellReselectionPriorities parameter, which also indicates the cell reselection priority by indicating the cellReselectionPriority and CellReselectionSubPriority corresponding to the corresponding frequency. When the UE receives the cell reselection priority, it will ignore the cell reselection priority carried in the system information.

[0062] The cell reselection priority is divided according to the carrier frequency, not the cell frequency. For example, cells with the same carrier frequency on the same radio access technology (RAT) have the same cell reselection priority, while cells with different carrier frequencies may have the same or different cell reselection priorities.

[0063] For a high-priority neighboring cell (or a high-priority cell), the UE starts measurement unconditionally. A high-priority neighboring cell refers to a neighboring cell whose corresponding cell reselection priority is higher than the cell reselection priority of the currently resident cell. The cell reselection priority corresponding to a cell refers to the cell reselection priority corresponding to the frequency of the cell.

[0064] For neighboring cells of equal priority (or cells of equal priority, which may include cells of the same frequency and / or cells of different frequencies of the currently resident cell), if it is a cell of the same frequency and Srxlev≤SIntraSearchP and Squal≤SIntraSearchQ are satisfied, the UE performs intra-frequency measurement. If it is a cell of different frequencies and Srxlev≤SnonIntraSearchP and Squal≤SnonIntraSearchQ are satisfied, the UE performs measurement of NR cells of different frequencies (inter-frequencies). Neighboring cells of equal priority refer to neighboring cells whose corresponding cell reselection priority is the same as the cell reselection priority of the currently resident cell.

[0065] For low-priority neighbor cells (or low-priority cells. Among them, there may be only low-priority neighbor cells of different frequencies and systems), if Srxlev≤SnonIntraSearchP and Squal≤SnonIntraSearchQ are satisfied, the UE performs measurement of NR inter-frequencies or inter-RAT cells. A low-priority neighbor cell refers to a neighbor cell whose corresponding cell reselection priority is lower than the cell reselection priority of the currently resident cell.

[0066] The parameters involved above can be found in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] In Table 1, "field" refers to a field used to carry corresponding parameters.

[0071] After the cell measurement is completed, the UE starts to determine the signal quality of the cell, or the UE determines whether the measured cell meets the cell reselection condition.

[0072] 1. Identification of high priority cells (or high priority neighboring cells).

[0073] For a high priority cell, if the system message (e.g. SIB2) of the cell broadcasts threshServingLowQ and more than 1 second has passed since the UE camped on the current camped cell, then cell reselection to an NR frequency or inter-RAT frequency with a higher cell reselection priority than the cell reselection priority corresponding to the frequency of the current camped cell shall be performed if: a cell with a higher priority NR or evolved UMTS terrestrial radio access network (E-UTRAN) RAT / frequency is selected within the time interval Treselection RAT During this period, the following relationship is satisfied:

[0074] Squal>Thresh X,HighQ (Formula 1)

[0075] Otherwise, cell reselection to an NR frequency or inter-RAT frequency with a higher cell reselection priority than the cell reselection priority corresponding to the frequency of the currently camped cell shall be performed in the following cases: a cell of the RAT or frequency with a higher cell reselection priority is not reached within the time interval Treselection RAT During this period, the following relations are satisfied:

[0076] Srxlev>Thresh X,HighP (Formula 2)

[0077] And, in addition to satisfying Formula 2, the cell with a RAT or frequency having a higher cell reselection priority is selected in the time interval Treselection RAT The period also satisfies that more than 1 second has passed since the UE camped on the current camping cell.

[0078] 2. Identification of cells of equal priority (or, neighboring cells of equal priority).

[0079] For cells with the same priority, cell reselection is performed based on the R criterion. The so-called R criterion is to calculate a rank (Rank, R) value for each neighboring cell and the current resident cell based on the signal quality of the cell, and sort them according to the size of the R value. If the R value of a neighboring cell is greater than the R value of the current resident cell, then the neighboring cell meets the cell reselection condition. If multiple neighboring cells meet the cell reselection condition, the one with the best signal quality can be selected from these multiple neighboring cells. If a neighboring cell continues to meet the R criterion for a period of time exceeding TreselectionRAT, and the UE has been resident in the current resident cell for more than 1 second, the UE initiates reselection to the neighboring cell.

[0080] 3. Identification of low-priority cells (or low-priority neighboring cells).

[0081] For low-priority cells, the cell reselection conditions are more stringent than those for reselecting to high-priority cells or cells of equal priority, as described below.

[0082] A. No cell among the high-priority cells meets the high-priority cell reselection conditions;

[0083] B. No cell among the cells of the same priority level meets the conditions for reselection of cells of the same priority level;

[0084] C. If a system message (e.g. SIB2) broadcasts threshServingLowQ and more than 1 second has elapsed since the UE camped on the currently camped cell, cell reselection to an NR frequency or inter-RAT frequency with a lower cell reselection priority than the cell reselection priority corresponding to the frequency of the currently camped cell shall be performed in the following cases:

[0085] (1) The serving cell meets Squal <Thresh Serving,LowQ ;

[0086] (2) The cell with lower priority RAT or frequency in the time interval Treselection RAT During the period, Squal>Thresh X,LowQ .

[0087] Otherwise, cell reselection to an NR frequency or inter-RAT frequency having a lower cell reselection priority than the cell reselection priority corresponding to the frequency of the currently camped cell shall be performed in the following cases:

[0088] a. The current resident cell meets Srxlev <Thresh Serving,LowP ;

[0089] b. The RAT or frequency cell with lower cell reselection priority is selected in the time interval TreselectionRAT During the period, Srxlev>Thresh X,LowP ;

[0090] c. More than 1 second has passed since the UE camped on the current camping cell.

[0091] The parameters in the above process can be found in Table 2.

[0092] Table 2

[0093]

[0094] After completing the neighboring cell measurement and confirming that there is a cell that meets the cell reselection condition, the UE will start trying to camp on the new cell. The following describes the UE camping process.

[0095] 1. The UE searches for the target cell.

[0096] 2. After searching for the target cell, the UE receives a system message from the target cell and determines whether the target cell can be normally occupied. For example, the UE determines whether the target cell is barred or reserved, or determines the access level, etc. according to the system message.

[0097] 3. After receiving the system message, the UE resides in the target cell. For example, if the target cell is not barred, the UE can reside in the target cell. At this point, the UE has reselected a new cell.

[0098] The above cell reselection related contents (such as cell reselection conditions and cell reselection procedures) are only examples and do not constitute a limitation on the embodiments of the present application. For example, the UE in the embodiments of the present application may also adopt other cell reselection conditions and / or other procedures to perform cell reselection.

[0099] The previous article introduced the contents related to cell reselection. The following article introduces the contents related to multicast services or broadcast services.

[0100] At present, in order to alleviate network congestion, it is proposed to support UEs that join a multicast session to receive multicast services in the RRC inactive state. For example, a cell releases the UE to the RRC inactive state through an RRC Release message. The RRC release message can indicate the cell reselection priority corresponding to the frequency used to receive multicast services in the RRC inactive state. Then the UE can reselect to the cell at this frequency to receive the multicast service in the RRC non-connected state.

[0101] But this approach may have problems. For example, Figure 1, the cell 1 of the UE at frequency 1 is released to the RRC non-connected state, and the RRC release message sent by cell 1 to the UE indicates frequency 2, then the UE can reselect to cell 2 at frequency 2 to receive the multicast service in cell 2. Although cell 2 is a cell at frequency 2, it may not provide the multicast service in the RRC non-activated state, that is, other cells except cell 2 at frequency 2 may provide the multicast service in the RRC non-activated state, but cell 2 does not. It can be seen that the UE may reselect to an inappropriate cell through the current mechanism, resulting in the UE being unable to receive the multicast service in the RRC non-connected state.

[0102] In view of this, the embodiment of the present application sets the effective range of the frequency. For example, the cell within the effective range may provide multicast services in the RRC non-connected state. Then, the RRC release message indicates the first frequency. When the first device performs cell reselection or cell selection, if the first candidate cell is selected, it does not directly reside in the first candidate cell, but determines whether the first candidate cell is included in the effective range corresponding to the first frequency. For example, if it is included in the effective range, it indicates that the first candidate cell may provide multicast services in the RRC non-connected state, then the first device can reside in the first candidate cell, thereby increasing the probability that the first device successfully receives the multicast service in the RRC non-connected state in the newly resided cell. Optionally, if the first candidate cell is not included in the effective range, the first device may not reside in the first candidate cell. For example, the first device may continue to select other candidate cells to receive multicast services in the RRC non-connected state as much as possible, instead of entering the RRC connected state in the first candidate cell to receive multicast data, thereby reducing the condition of entering the RRC connected state and reducing the congestion of the cell.

[0103] The technical solution provided in the embodiments of the present application can be applied to the fourth generation mobile communication technology (the 4th generation, 4G) system, such as the LTE system, or can be applied to the fifth generation mobile communication technology (the 5th generation, 5G) system, such as the NR system, or can also be applied to the next generation mobile communication system or other similar communication systems, such as the sixth generation mobile communication technology (the 6th generation, 6G) system, etc., without specific limitation. In addition, the technical solution provided in the embodiments of the present application can be applied to the side link (sidelink, SL). For example, the SL belongs to a D2D scenario, such as an NR-D2D scenario, etc., or belongs to a V2X scenario, such as an NR-V2X scenario, etc. For example, the embodiments of the present application can be used in the fields of factory manufacturing, whole-house intelligence, intelligent driving, assisted driving, intelligent networked vehicles, or indoor commercial scenarios.

[0104] For reference Figure 2, which is a communication network architecture applicable to the embodiments of the present application. Figure 2 Including UE, the UE resides in cell 1. Then the UE starts the cell reselection process and selects a cell by the method provided in the embodiment of the present application. Or the UE may not initially reside in a cell, and the UE can start the cell selection process and select a cell by the method provided in the embodiment of the present application. For example Figure 2 Cell 2 in the cell selection or cell reselection process is a candidate cell. The frequency of cell 2 is the same as or different from the frequency of cell 1. The UE can execute the method provided in the embodiment of the present application.

[0105] In order to better introduce the embodiments of the present application, the method provided by the embodiments of the present application is introduced below in conjunction with the accompanying drawings. In various embodiments of the present application, the RRC non-connected state of the UE may refer to a state in which there is no connection between the RRC layer of the UE and the RRC layer of the access network device, for example, including an RRC idle state or an RRC inactive state. In various embodiments of the present application, multicast services are taken as an example for introduction. Optionally, the multicast service may also be replaced by a broadcast service or a multicast service. Various embodiments of the present application may involve a cell reselection process, or involve a cell selection process. In the following text, the cell reselection process is mainly taken as an example. Unless otherwise specified in the following text, the steps represented by dotted lines in the accompanying drawings corresponding to the various embodiments of the present application are all optional steps.

[0106] Each embodiment of the present application may be executed by a first device. The first device is, for example, a UE, or a functional module capable of executing the method provided in the embodiment of the present application. The functional module may be set in the UE, such as a chip system in the UE; or the functional module may be set independently of the UE. In the following introduction, the first device is taken as an example of a UE. The methods provided in each embodiment of the present application can be applied to Figure 2 The network architecture shown, for example, the UE involved in each embodiment of the present application may be Figure 2 UE in.

[0107] This application embodiment provides a communication method, see Figure 3 , which is a flow chart of the method.

[0108] S301. The first cell sends an RRC release message to the UE. Correspondingly, the UE receives the RRC release message from the first cell.

[0109] The RRC release message may be used to release the UE to the RRC non-connected state, or the RRC release message may be used to release the UE to receive multicast services in the RRC non-connected state. In addition, the RRC release message may also indicate a first frequency, the first frequency being, for example, a frequency that may provide multicast services in the RRC non-connected state, or a cell under the first frequency may provide multicast services in the RRC non-connected state, or a cell under the first frequency has a greater probability of providing multicast services in the RRC non-connected state, or a cell under the first frequency can provide multicast services in the RRC non-connected state, or a cell under the first frequency supports providing multicast services in the RRC non-connected state, or a cell under the first frequency is providing multicast services in the RRC non-connected state, or a cell under the first frequency is about to provide multicast services in the RRC non-connected state. Whether a cell provides multicast services in the RRC non-connected state may be determined based on the degree of congestion of the network, and therefore may change dynamically, for example, a cell provides multicast services in the RRC non-connected state in a certain period of time, but may not provide multicast services in the RRC non-connected state in the next period of time. Therefore, in the embodiment of the present application, the first frequency is a frequency that "may" provide multicast services in the RRC non-connected state, that is, the first frequency may not be a frequency that "definitely can" provide multicast services in the RRC non-connected state.

[0110] Optionally, the RRC release message may also indicate the priority of the first frequency, which may be the cell reselection priority described above, and is hereinafter referred to as the priority. The priority of the first frequency may be used for the UE to perform cell reselection for receiving multicast services in an RRC non-connected state; or, the UE may perform cell reselection in order to receive multicast services in an RRC non-connected state, and the priority of the first frequency may be used during the cell reselection process. For example, the UE may perform cell reselection in order to receive multicast services in an RRC non-connected state, and the priority of the first frequency may be used during the cell reselection process. The first frequency may include one or more frequencies, and the priorities corresponding to different frequencies in the one or more frequencies may be the same or different. Optionally, because the cell under the first frequency may provide a multicast service in an RRC non-connected state, the first frequency may be regarded as a frequency that provides a multicast service in an RRC non-connected state, so the first frequency may also be referred to as a dedicated frequency, and the priority of the first frequency may also be understood as a dedicated frequency priority. In addition, the one or more frequencies included in the first frequency may include the frequency of the first cell, or may not include the frequency of the first cell.

[0111] Optionally, the RRC release message may also indicate the effective range of the first frequency; or the effective range may not be indicated by the RRC release message, for example, the effective range may be predefined by a protocol, or preconfigured in the UE, or indicated by other messages from the first cell (for example, an MBS control channel (MCCH) message or an RRC reconfiguration message, etc.). The effective range of the first frequency may indicate a cell or area that provides a multicast service in an RRC non-connected state at the first frequency, for example, the effective range may indicate a cell or area that may provide a multicast service in an RRC non-connected state at the first frequency, or indicate a cell or area that has a high probability of providing a multicast service in an RRC non-connected state at the first frequency, or indicate a cell or area that supports providing a multicast service in an RRC non-connected state at the first frequency, or indicate a cell or area that is providing a multicast service in an RRC non-connected state at the first frequency, or indicate a cell or area that is about to provide a multicast service in an RRC non-connected state at the first frequency. Among them, if the first frequency includes one frequency, the effective scope of the first frequency may include the effective scope of the frequency; or, if the first frequency includes multiple frequencies, the effective scope of the first frequency may respectively include the effective scope of each frequency in the multiple frequencies. Optionally, for a certain frequency included in the first frequency, the effective scope corresponding to the frequency may be empty, or may not be empty. If it is empty, it indicates that there is no cell or area that may provide multicast services in the RRC non-connected state at this frequency, or that there is no cell or area that is currently providing multicast services in the RRC non-connected state at this frequency, or that there is no cell or area that supports providing multicast services in the RRC non-connected state at this frequency, or that there is no cell or area that is about to provide multicast services in the RRC non-connected state at this frequency.

[0112] Optionally, the effective scope of the first frequency (or the effective scope of a certain frequency A in the first frequency) may include (or indicate) one or more of the following: information of some or all cells under the first frequency (or frequency A) (e.g., cell identifiers), one or more radio access network-area codes (RNA) under the first frequency (or frequency A), or one or more tracking area codes (tracking area code) under the first frequency (or frequency A). For example, if the effective scope includes information of some or all cells under the first frequency, then the effective scope is equivalent to indicating that these cells may provide multicast services in the RRC non-connected state. For another example, if the effective scope of the first frequency includes one or more RNAs under the first frequency, then the effective scope is equivalent to indicating that the cells within these RNAs may provide multicast services in the RRC non-connected state. For another example, if the effective scope of the first frequency includes one or more tracking area codes under the first frequency, then the effective scope is equivalent to indicating that the cells corresponding to these tracking area codes may provide multicast services in the RRC non-connected state.

[0113] For example, the RRC release message indicates the following: frequency f1, priority of frequency f1 (priority 5), effective range of frequency f1 (cell 0, cell 7); frequency f2, priority of frequency f2 (priority 6), effective range of frequency f2 (cell 1); frequency f3, priority of frequency f3 (priority 4), effective range of frequency f3 (cell 5, cell 6).

[0114] Among them, the first frequency may include one or more frequencies, and the one or more frequencies may include the frequency of the first cell and / or the frequencies of other cells except the first cell. The other cells may include cells provided by the network device corresponding to the first cell and / or cells provided by other network devices except the network device. If the effective range is indicated by the RRC release message or other messages from the first cell, and the first frequency includes frequencies provided by other network devices except the network device corresponding to the first cell, the effective range corresponding to these frequencies can be obtained through interaction between network devices. For example, the network device corresponding to the first cell can receive messages from other network devices through the Xn interface, and the message may indicate the effective range corresponding to some or all frequencies corresponding to the other network devices. Optionally, the message is, for example, a next generation (NG)-radio access network (RAN) mode configuration update message.

[0115] S302. The UE enters an RRC unconnected state based on the RRC release message.

[0116] The RRC release message is used to release the UE, so the UE can enter the RRC non-connected state after receiving the RRC release message. The UE enters the RRC non-connected state to perform a cell selection process, and the UE can select and reside in a second cell, which is, for example, the first cell, or a cell other than the first cell.

[0117] S303: If the first candidate cell at the first frequency is included in the effective range corresponding to the first frequency, the UE resides in the first candidate cell. Alternatively, if the first candidate cell at the first frequency is not included in the effective range corresponding to the first frequency, the UE does not reside in the first candidate cell.

[0118] For example, S303 includes a cell reselection process of the UE, wherein the UE may perform cell reselection in the second cell. The second cell may be the first cell, that is, the UE may perform cell reselection after the first cell enters the RRC non-connected state. For example, the UE moves in the first cell and may perform cell reselection when it moves to the edge of the first cell.

[0119] Alternatively, the second cell and the first cell may also be different cells. For example, after the UE enters the RRC non-connected state in the first cell, it performs cell reselection and reselects the second cell. Then, the UE may reside in the second cell. After residing in the second cell, the UE may perform cell reselection again; or, when the first cell is released to the RRC non-connected state, the UE may perform cell selection and enter the second cell. After residing in the second cell, the UE may perform cell reselection. There are different execution modes for the UE to perform cell reselection in the second cell, as described below.

[0120] 1. The first optional cell reselection method of UE.

[0121] Optionally, for one or more frequencies in the first frequency, the UE may set the priority of the frequency with the highest priority as the current highest priority, or the UE may set the priority of the frequency with the highest priority and the corresponding effective range not being empty as the current highest priority, or the UE may set the priority of the frequency with the highest priority, the corresponding effective range not being empty, and the corresponding effective range not including or not only including the second cell as the current highest priority. The UE setting the priority of a frequency as the highest priority can also be described as the UE setting the frequency as the highest priority frequency. When performing cell reselection, the UE can preferentially determine whether it can reselect the candidate cell under the frequency with the highest priority. An effective range includes not only the second cell, for example, the effective range may include information of multiple cells, and the multiple cells may include the second cell, and may also include other cells except the second cell.

[0122] For example, the RRC release message indicates the following: frequency f1, priority of frequency f1 (priority 5), effective range of frequency f1 (cell 0, cell 7); frequency f2, priority of frequency f2 (priority 6), effective range of frequency f2 (cell 1); frequency f3, priority of frequency f3 (priority 4), effective range of frequency f3 (cell 5, cell 6). For example, cell 1 is the second cell. Among them, priority 6 is higher than priority 5, and priority 5 is higher than priority 4. Among these three priorities, priority 6 is the highest. However, the effective range of frequency f2 corresponding to priority 6 only includes the second cell. Since the UE is currently residing in the second cell, the UE can ignore frequency f2 and set the priority of frequency f1 (priority 5) to the current highest priority, or set frequency f1 to the highest priority frequency.

[0123] When performing cell reselection, the UE may give priority to the cell at the frequency corresponding to the current highest priority from the candidate cell list. For example, if the UE sets priority 5 as the current highest priority, the UE may give priority to the cell at frequency f1. For example, if the UE selects candidate cell 1 at frequency f1 from the candidate list, the UE may measure candidate cell 1 in accordance with the measurement method for high-priority cells. After obtaining the measurement result, the UE may determine whether the signal quality of candidate cell 1 meets the cell reselection condition according to the measurement result. If candidate cell 1 does not meet the cell reselection condition, the UE does not reside in candidate cell 1, for example, the UE selects the next candidate cell in the candidate cell list, wherein the UE still gives priority to the candidate cell at the frequency corresponding to the current highest priority, for example, the candidate cell at frequency f1. If the candidate cell list no longer includes the candidate cell at frequency f1, the UE may select the candidate cell at the frequency corresponding to the next priority in the first frequency (also the frequency included in the first frequency) in order of priority from high to low. Optionally, if the UE selects the candidate cell at the frequency corresponding to the next priority in the first frequency in the candidate cell list, the UE may set the next priority to the current highest priority. For example, continuing the above example, the first frequency includes the above frequency f1, frequency f2 and frequency f3. Since the UE has ignored frequency f2, and there is no suitable candidate cell in the candidate cells under frequency f1, the next priority in the first frequency is priority 4. Priority 4 corresponds to frequency f3 in the first frequency, and the UE can select the candidate cell under frequency f3 in the candidate cell list. Optionally, the UE can set priority 4 to the current highest priority. After selecting the candidate cell under frequency f3, the execution steps of the UE are similar to those after selecting candidate cell 1.

[0124] Alternatively, if the UE determines that candidate cell 1 meets the cell reselection condition based on the measurement result, the UE may continue to determine whether candidate cell 1 is located in the effective range corresponding to the first frequency. For example, if candidate cell 1 is a cell under frequency f1, the effective range corresponding to the first frequency includes the effective range corresponding to frequency f1, and the effective range corresponding to frequency f1 is (cell 0, cell 7), the UE may determine whether candidate cell 1 is cell 0 or cell 7. If candidate cell 1 is cell 0 or cell 7, the UE may reside in candidate cell 1. Alternatively, if candidate cell 1 is neither cell 0 nor cell 7, the UE does not reside in candidate cell 1, and the UE selects the next candidate cell in the candidate cell list. The selection method may refer to the introduction in the previous paragraph.

[0125] According to the above, the UE can perform the process of setting the highest priority. According to the introduction of the cell reselection process in the previous text, when the UE measures the cell, the measurement method for the high priority cell, the equal priority cell, and the low priority cell is different. Then, if the UE performs the process of setting the highest priority, the UE will measure the signal quality of any selected candidate cell as a high priority cell, that is, the signal quality of any candidate cell is measured according to the measurement method of the high priority cell. Similarly, when the UE determines the signal quality of the cell (that is, determines whether the cell meets the cell reselection condition), the determination method for the high priority cell, the equal priority cell, and the low priority cell is also different. Then, if the UE performs the process of setting the highest priority, the UE will determine the signal quality of any selected candidate cell as a high priority cell, that is, the signal quality of any candidate cell is determined according to the determination method of the high priority cell.

[0126] For example, reference Figure 4A , is a flowchart of a cell reselection process under the first cell reselection mode of UE, Figure 4A Take the UE setting the highest priority as an example. Figure 4A It can be seen that after the UE resides in the second cell, it performs cell reselection. If there is a high-priority candidate cell (for example, the UE selects the cell at the frequency corresponding to the current highest priority (the highest priority set by the UE) from the candidate cell list), the UE can measure the candidate cell in the same way as the high-priority cell, and determine whether the candidate cell meets the cell reselection condition based on the measurement result. If the candidate cell meets the cell reselection condition, the UE can continue to determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell. If the candidate cell is included in the effective range corresponding to the frequency of the candidate cell, the UE resides in the candidate cell; or, if the candidate cell is not included in the effective range corresponding to the frequency of the candidate cell, the UE does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to identify the next candidate cell.

[0127] Or if the candidate cell does not meet the cell reselection condition, the UE does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to determine the next candidate cell.

[0128] Alternatively, there is another implementation method, the UE may not have to perform the process of setting the highest priority, for example, the UE may not have to set the priority corresponding to the frequency to be selected as the highest priority. For example, the first frequency includes one or more frequencies, and the one or more frequencies correspond to respective priorities, and these priorities are the same or different. When performing cell reselection, the UE may give priority to determining whether it can reselect the candidate cell under the frequency with the highest priority among the one or more frequencies (the highest priority is the actual highest priority, not the highest priority set by the UE), or the UE may give priority to determining whether it can reselect the frequency with the highest corresponding priority and a non-empty effective range among the one or more frequencies, or the UE may give priority to determining whether it can reselect the frequency with the highest corresponding priority among the one or more frequencies, and the corresponding effective range is not empty, and the corresponding effective range does not include or not only includes the second cell.

[0129] For example, continuing with the above example, among the three priorities indicated by the RRC release message, priority 6 is the highest. However, the frequency f2 corresponding to priority 6 only includes the second cell in its effective range. Since the UE currently resides in the second cell, the UE can ignore frequency f2 when performing cell reselection, or if the UE believes that there is no candidate cell under frequency f2, the UE can prioritize whether it can reselect to a candidate cell under frequency f1. The cell reselection process of the UE can be referred to above. The difference is that in this implementation, the UE does not need to perform the process of setting the highest priority, which is conducive to simplifying the cell reselection process of the UE.

[0130] If the UE does not perform the process of setting the highest priority, then for a selected candidate cell, the UE can determine the relationship between the priority corresponding to the frequency of the candidate cell and the priority corresponding to the frequency of the second cell when performing measurement. For example, if the priority corresponding to the frequency of the candidate cell is higher than the priority corresponding to the frequency of the second cell, the UE can measure the candidate cell as a high-priority cell, that is, measure the signal quality of the candidate cell in accordance with the measurement method for a high-priority cell; or, if the priority corresponding to the frequency of the candidate cell is equal to the priority corresponding to the frequency of the second cell, the UE can measure the candidate cell as an equal-priority cell, that is, measure the signal quality of the candidate cell in accordance with the measurement method for equal-priority cells; or, if the priority corresponding to the frequency of the candidate cell is lower than the priority corresponding to the frequency of the second cell, the UE can measure the candidate cell as a low-priority cell, that is, measure the signal quality of the candidate cell in accordance with the measurement method for a low-priority cell. Similarly, for a selected candidate cell, the UE can also determine the relationship between the priority corresponding to the frequency of the candidate cell and the priority corresponding to the frequency of the second cell when judging the signal quality. For example, if the priority corresponding to the frequency of the candidate cell is higher than the priority corresponding to the frequency of the second cell, the UE may judge the candidate cell as a high-priority cell, that is, judge the signal quality of the candidate cell according to the method of judging high-priority cells; or, if the priority corresponding to the frequency of the candidate cell is equal to the priority corresponding to the frequency of the second cell, the UE may judge the candidate cell as an equal-priority cell, that is, judge the signal quality of the candidate cell according to the method of judging equal-priority cells; or, if the priority corresponding to the frequency of the candidate cell is lower than the priority corresponding to the frequency of the second cell, the UE may judge the candidate cell as a low-priority cell, that is, judge the signal quality of the candidate cell according to the method of judging low-priority cells.

[0131] For example, reference Figure 4B , is a flowchart of another cell reselection process under the first cell reselection mode of the UE, Figure 4B Take the example of UE not setting the highest priority. Figure 4BIt can be seen that after the UE camps on the second cell, it performs cell reselection. If there is a candidate cell with a high priority (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is higher than the priority corresponding to the frequency of the second cell), the UE can measure the candidate cell according to the measurement method of the high priority cell, and determine whether the candidate cell meets the cell reselection condition according to the determination method of the high priority cell based on the measurement result; or, if there are candidate cells with the same priority (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is equal to the priority corresponding to the second cell), the UE can determine whether the candidate cell meets the cell reselection condition according to the determination method of the high priority cell based on the measurement result; If the UE has selected a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency of the second cell is lower than the priority corresponding to the frequency of the second cell), the UE may measure the candidate cell in the measurement method for the candidate cell of the same priority, and determine whether the candidate cell meets the cell reselection condition according to the determination method for the same priority cell based on the measurement result; or, if there is a candidate cell with a low priority (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is lower than the priority corresponding to the frequency of the second cell), the UE may measure the candidate cell in the measurement method for the low priority cell, and determine whether the candidate cell meets the cell reselection condition according to the determination method for the low priority cell based on the measurement result. Wherein, regardless of the determination method, if the candidate cell meets the cell reselection condition, the UE may continue to determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell. If the candidate cell is included in the effective range corresponding to the frequency of the candidate cell, the UE resides in the candidate cell; or, if the candidate cell is not included in the effective range corresponding to the frequency of the candidate cell, the UE does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to determine the next candidate cell.

[0132] Alternatively, regardless of the determination method, if the candidate cell does not meet the cell reselection condition, the UE does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to determine the next candidate cell.

[0133] 2. A second optional cell reselection method of UE.

[0134] In the first cell reselection method as described above, after the UE selects a candidate cell from the candidate cell list, it first measures the candidate cell, and determines whether the candidate cell meets the cell reselection condition based on the measurement result. If the candidate cell meets the cell reselection condition, the UE then determines whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell (included in the first frequency).

[0135] In the second cell reselection method, after the UE selects a candidate cell from the candidate cell list, it can first measure the candidate cell. After the measurement, the UE may not determine whether the candidate cell meets the cell reselection condition, but first determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell (included in the first frequency). If the candidate cell is included in the effective range corresponding to the frequency of the candidate cell, the UE can continue to determine whether the candidate cell meets the cell reselection condition. If the candidate cell meets the cell reselection condition, the UE can reside in the candidate cell; or, if the candidate cell does not meet the cell reselection condition, the UE may not reside in the candidate cell, for example, the UE can continue to execute the cell reselection process, or continue to determine the next candidate cell.

[0136] Alternatively, if the candidate cell is not included in the effective range corresponding to the frequency of the candidate cell, the UE may no longer need to determine whether the candidate cell meets the cell reselection condition, but may not reside in the candidate cell. For example, the UE may continue to execute the cell reselection process, or may continue to identify the next candidate cell. It can be seen that in the second cell reselection method, if a candidate cell is not included in the effective range corresponding to the first frequency, the UE may not need to perform the judgment of whether the candidate cell meets the cell reselection condition, which is beneficial to reduce the processing process of the UE and reduce the power consumption of the UE. For more implementation details of the second cell reselection method, such as whether the UE can perform the processing of setting the highest priority, or the UE may not perform the processing of setting the highest priority, as well as the specific reselection process of the UE, etc., please refer to the introduction of the first cell reselection method mentioned above.

[0137] For example, reference Figure 5A , is a flowchart of a cell reselection process under the second cell reselection mode of UE, Figure 5A Take the UE setting the highest priority as an example. Figure 5A It can be seen that after the UE resides in the second cell and performs cell reselection, if there is a high-priority candidate cell (for example, the UE selects a cell under the frequency corresponding to the current highest priority from the candidate cell list), the UE can measure the candidate cell in the same way as the high-priority cell. After the measurement, the UE can determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell. If the candidate cell is included in the effective range corresponding to the frequency of the candidate cell, the UE can determine whether the candidate cell meets the cell reselection condition according to the measurement result of the candidate cell and the high-priority cell. If the candidate cell meets the cell reselection condition, the UE can reside in the candidate cell; or, if the candidate cell does not meet the cell reselection condition, the UE may not reside in the candidate cell and continue to perform cell reselection, or continue to determine the next candidate cell.

[0138] Alternatively, if the candidate cell is not included in the effective range corresponding to the frequency of the candidate cell, the UE may not reside in the candidate cell, for example, continue to perform cell reselection, or continue to determine the next candidate cell.

[0139] For another example, please refer to Figure 5B , is a flowchart of another cell reselection process under the second cell reselection mode of the UE, Figure 5B Take the example of UE not setting the highest priority. Figure 5B It can be known that after the UE resides in the second cell and performs cell reselection, if there is a high-priority candidate cell (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is higher than the priority corresponding to the frequency of the second cell), the UE can measure the candidate cell in accordance with the measurement method of the high-priority cell; or, if there is an equal-priority candidate cell (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is equal to the priority corresponding to the frequency of the second cell), the UE can measure the candidate cell in accordance with the measurement method of the equal-priority cell; or, if there is a low-priority candidate cell (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is lower than the priority corresponding to the frequency of the second cell), the UE can measure the candidate cell in accordance with the measurement method of the low-priority cell. Regardless of whether the candidate cell is a high-priority cell, an equal-priority cell or a low-priority cell, after measurement, the UE can determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell. If the candidate cell is included in the effective range corresponding to the frequency of the candidate cell, the UE can determine whether the candidate cell meets the cell reselection condition according to the measurement result. Among them, if the candidate cell is a high-priority cell, the UE determines whether the candidate cell meets the cell reselection condition according to the determination method for high-priority cells; or, if the candidate cell is an equal-priority cell, the UE determines whether the candidate cell meets the cell reselection condition according to the determination method for equal-priority cells; or, if the candidate cell is a low-priority cell, the UE determines whether the candidate cell meets the cell reselection condition according to the determination method for low-priority cells. Regardless of the determination method, if the candidate cell meets the cell reselection condition, the UE resides in the candidate cell; or, if the candidate cell does not meet the cell reselection condition, the UE does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to determine the next candidate cell.

[0140] Alternatively, if the candidate cell is not included in the effective range corresponding to the frequency of the candidate cell, the UE does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to determine the next candidate cell.

[0141] 3. The third optional cell reselection method of UE.

[0142] In the third cell reselection mode, after the UE selects a candidate cell from the candidate cell list, it may not measure the candidate cell first, but first determine whether the candidate cell is included in the effective range corresponding to the first frequency. If the candidate cell is included in the effective range corresponding to the first frequency, the UE may measure the candidate cell and determine whether the candidate cell meets the cell reselection condition. If the candidate cell meets the cell reselection condition, the UE may reside in the candidate cell; or, if the candidate cell does not meet the cell reselection condition, the UE may not reside in the candidate cell, for example, the UE may continue to execute the cell reselection process, or continue to determine the next candidate cell.

[0143] Alternatively, if the candidate cell is not included in the effective range corresponding to the first frequency, the UE may no longer perform measurement and other processes, but may not reside in the candidate cell, for example, the UE may continue to perform the cell reselection process. It can be seen that in the third cell reselection method, if a candidate cell is not included in the effective range corresponding to the first frequency, the UE may not have to perform more processes such as measurement, which can reduce the UE's processing to a greater extent and further reduce the UE's power consumption. For more implementation details of the third cell reselection method, such as whether the UE can perform the processing of setting the highest priority, or whether the UE may not perform the processing of setting the highest priority, as well as the specific reselection process of the UE, etc., please refer to the introduction of the aforementioned first cell reselection method.

[0144] For example, reference Fig. 6A , is a flowchart of a cell reselection process under the third cell reselection mode of UE, Fig. 6A Take the UE setting the highest priority as an example. Fig. 6AIt can be seen that after the UE resides in the second cell and performs cell reselection, if there is a high-priority candidate cell (for example, the UE selects a cell at the frequency corresponding to the current highest priority from the candidate cell list), the UE can determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell. If the candidate cell is included in the effective range corresponding to the frequency of the candidate cell, the UE can measure the candidate cell in accordance with the measurement method of the high-priority cell, and determine whether the candidate cell meets the cell reselection condition in accordance with the determination method of the high-priority cell based on the measurement result of the candidate cell. If the candidate cell meets the cell reselection condition, the UE can reside in the candidate cell; or, if the candidate cell does not meet the cell reselection condition, the UE may not reside in the candidate cell and continue to perform cell reselection, or continue to determine the next candidate cell.

[0145] Alternatively, if the candidate cell is not included in the effective range corresponding to the frequency of the candidate cell, the UE may no longer perform measurement and other processes, but may not reside in the candidate cell, for example, continue to perform cell reselection.

[0146] For another example, please refer to Figure 6B , is a flowchart of another cell reselection process under the third cell reselection mode of UE, Figure 6B Take the example of UE not setting the highest priority. Figure 6BIt can be known that after the UE resides in the second cell and performs cell reselection, if there is a candidate cell with a high priority (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is higher than the priority corresponding to the frequency of the second cell), the UE can determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell; or, if there is a candidate cell with an equal priority (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is equal to the priority corresponding to the frequency of the second cell), the UE can determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell; or, if there is a candidate cell with a low priority (for example, the UE selects a candidate cell at a certain frequency in the first frequency from the candidate cell list, and the priority corresponding to the frequency is lower than the priority corresponding to the frequency of the second cell), it can determine whether the candidate cell is included in the effective range corresponding to the frequency of the candidate cell. Regardless of whether the candidate cell is a high priority cell, an equal priority cell or a low priority cell, if the candidate cell is included in the effective range corresponding to the frequency of the candidate cell, the UE can measure the candidate cell and determine whether the candidate cell meets the cell reselection condition according to the measurement result. Wherein, if the candidate cell is a high priority cell, the UE measures the signal quality of the candidate cell in accordance with the measurement method for high priority cells; or, if the candidate cell is an equal priority cell, the UE measures the signal quality of the candidate cell in accordance with the measurement method for equal priority cells; or, if the candidate cell is a low priority cell, the UE measures the signal quality of the candidate cell in accordance with the measurement method for low priority cells. In addition, if the candidate cell is a high priority cell, the UE determines whether the candidate cell meets the cell reselection condition in accordance with the determination method for high priority cells; or, if the candidate cell is an equal priority cell, the UE determines whether the candidate cell meets the cell reselection condition in accordance with the determination method for equal priority cells; or, if the candidate cell is a low priority cell, the UE determines whether the candidate cell meets the cell reselection condition in accordance with the determination method for low priority cells. Regardless of the determination method, if the candidate cell meets the cell reselection condition, the UE resides in the candidate cell; or, if the candidate cell does not meet the cell reselection condition, the UE does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to determine the next candidate cell.

[0147] Alternatively, if the candidate cell is not included in the effective range corresponding to the frequency of the candidate cell, the UE does not need to perform measurement and other processes, but does not reside in the candidate cell, for example, continues to perform cell reselection, or continues to determine the next candidate cell.

[0148] 4. The fourth optional cell reselection method of UE.

[0149] In the fourth cell reselection method, the UE can perform screening when generating the candidate cell list. For example, cells included in the effective range corresponding to the first frequency can be added to the candidate cell list, while cells not included in the effective range corresponding to the first frequency may not be added to the candidate cell list. The candidate cell list obtained in this way includes candidate cells that are all within the effective range corresponding to the first frequency. For example, before the UE adds the information of a cell to the candidate cell list, it can first determine whether the cell is included in the effective range corresponding to the first frequency. If the cell is included in the effective range corresponding to the first frequency, the UE can add the information of the cell to the candidate cell list; if the cell is not included in the effective range corresponding to the first frequency, the UE will not add the information of the cell to the candidate cell list.

[0150] When performing cell reselection, for a candidate cell, the UE can measure the candidate cell and determine whether the candidate cell meets the cell reselection condition. If the candidate cell meets the cell reselection condition, the UE can reside in the candidate cell; or, if the candidate cell does not meet the cell reselection condition, the UE may not reside in the candidate cell, for example, the UE can continue to perform the cell reselection process, or continue to determine the next cell.

[0151] It can be seen that in the fourth cell reselection method, if a cell is not included in the effective range corresponding to the first frequency, the UE may not use the cell as a candidate cell, which can simplify the cell reselection process of the UE to a greater extent and further reduce the power consumption of the UE. For more implementation details of the fourth cell reselection method, such as whether the UE can perform the process of setting the highest priority, or whether the UE can also not perform the process of setting the highest priority, and the specific reselection process of the UE, please refer to the introduction of the third cell reselection method mentioned above.

[0152] As for the above-mentioned cell reselection methods, which one the UE uses can be configured by the network device, or predefined by the protocol, or preconfigured in the UE, or determined by the UE itself. In addition, for the measurement conditions and cell reselection conditions corresponding to different cells such as high priority cells, equal priority cells, and low priority cells, please refer to the introduction in the previous article.

[0153] If the UE resides in the first candidate cell, optionally, the UE may receive the multicast service in the first candidate cell in an RRC non-connected state.

[0154] Optionally, for any one or more of the above three cell reselection methods, a first threshold value may be set, and the first threshold value may be a number threshold value, for example, the first threshold value may also be called the maximum number of fallbacks or the maximum number of reselections or the maximum number of selections, etc., and the name is not limited. The first threshold value may be understood as the number threshold value of the number of times the UE selects a candidate cell from the candidate cell list. For example, during a cell reselection process (the cell reselection process before the UE performs the residence is considered as a cell reselection process, during which the UE may perform one or more processes of selecting a candidate cell from the cell reselection list), if the number of times the candidate cell is selected from the candidate cell list is greater than or equal to the first threshold value, the UE may reside in the candidate cell selected last time. For example, it is understood that the UE selects a candidate cell from the cell candidate list for the Nth time, N is greater than or equal to the first threshold value, and the candidate cell selected this time still cannot reside. At this time, the UE may stop the cell reselection, even if the candidate cell selected this time still does not meet the conditions (for specific conditions, please refer to the introduction of any one or more of the above three cell reselection methods), the UE can still reside in the candidate cell selected this time. In this way, the probability of the UE entering a cell reselection dead loop can be reduced, and the UE can resume the normal working process. Optionally, the candidate cell finally selected by the UE may not be within the effective range, but may meet other residency conditions such as cell reselection conditions. Otherwise, if the UE resides in a candidate cell with poor signal quality, the UE may be unable to perform the communication process.

[0155] The first threshold value may be configured by a network device, such as a network device corresponding to the first cell, a network device corresponding to the second cell, or a network device corresponding to other cells. For example, the network device may configure the first threshold value for the UE through information such as a system message, an RRC release message, or an RRC reconfiguration message. Alternatively, the first threshold value may also be predefined through a protocol, or may also be preconfigured in the UE, or may also be configured by the UE itself.

[0156] The embodiment of the present application sets the effective range of the frequency. For example, the cell within the effective range may provide multicast services in the RRC non-connected state. Then, the RRC release message indicates the first frequency. When the UE performs cell reselection or cell selection, if the first candidate cell is selected, it does not directly reside in the first candidate cell, but determines whether the first candidate cell is included in the effective range corresponding to the first frequency. For example, if it is included in the effective range, it indicates that the first candidate cell may provide multicast services in the RRC non-connected state, then the UE can reside in the first candidate cell, thereby increasing the probability that the UE successfully receives the multicast service in the RRC non-connected state in the newly resided cell. Optionally, if the first candidate cell is not included in the effective range, the UE may not reside in the first candidate cell. For example, the UE can continue to select other candidate cells to receive multicast services in the RRC non-connected state as much as possible, instead of entering the RRC connected state in the first candidate cell to receive multicast data, thereby reducing the situation of entering the RRC connected state and reducing the congestion of the cell. In addition, in the embodiment of the present application, the UE can also have different ways when performing cell reselection, which is more flexible.

[0157] Next, another communication method provided by the embodiment of the present application is introduced. Figure 7 , which is a flow chart of the method.

[0158] S701: The UE determines that a first candidate cell does not provide a multicast service in an RRC non-connected state. For example, the UE is in an RRC non-connected state.

[0159] For example, S701 includes a cell reselection process of the UE, wherein the UE may perform cell reselection in the second cell. The second cell is, for example, the first cell, and the first cell is the cell to which the UE is released to the RRC non-connected state, that is, the UE is first in the RRC connected state in the first cell, and then receives an RRC release message in the first cell and enters the RRC non-connected state. After the first cell enters the RRC non-connected state, the UE may perform cell reselection. For example, the UE moves in the first cell, and may perform cell reselection when it moves to the edge of the first cell.

[0160] Alternatively, the second cell and the first cell may also be different cells. For example, after the UE enters the RRC non-connected state in the first cell, it performs cell reselection and reselects the second cell. Then, the UE may reside in the second cell. After residing in the second cell, the UE may perform cell reselection again; or, when the first cell is released to the RRC non-connected state, the UE may perform cell selection and enter the second cell. After residing in the second cell, the UE may perform cell reselection.

[0161] During the cell reselection process, for example, if the UE selects the first candidate cell in the candidate cell list, the UE can determine whether it can reside in the first candidate cell. For example, the UE can measure the first candidate cell and determine whether the first candidate cell meets the cell reselection condition based on the measurement result. If the first candidate cell meets the cell reselection condition, the UE can reside in the first candidate cell. If the first candidate cell does not meet the cell reselection condition, the UE does not reside in the first candidate cell, but can continue to perform cell reselection. Alternatively, whether the UE can reside in the first candidate cell can also be determined based on Figure 3 The embodiment shown in the figure provides any one of the three cell reselection methods to determine, for which reference may be made to Figure 3 Introduction to S303 of the illustrated embodiment.

[0162] If the UE determines that it can reside in the first candidate cell, the UE originally expects to receive multicast services in the first candidate cell while being in an RRC non-connected state. However, when the UE determines that it can reside in the first candidate cell, the first candidate cell may be providing multicast services in an RRC non-connected state, or may not be providing multicast services in an RRC non-connected state. If the first candidate cell does not currently provide multicast services in an RRC non-connected state, the UE determines that the first candidate cell does not provide multicast services in an RRC non-connected state. For example, if the UE in an RRC non-connected state does not obtain the configuration of the multicast service it expects to receive through an MCCH message in the first candidate cell, it can be determined that the first candidate cell does not provide multicast services in an RRC non-connected state. Alternatively, when the UE is in the first cell (or, the second cell), it receives a first message from the first cell (or, the second cell), and the first message indicates a first frequency. For an explanation of the first frequency, please refer to Figure 3 S301 of the embodiment shown: If the first frequency does not include the frequency of the first candidate cell, the UE may determine that the first candidate cell does not provide a multicast service in the RRC non-connected state.

[0163] Among them, S701 is an optional step. For example, the UE may not determine or know whether the first candidate cell provides multicast services in the RRC non-connected state, but executes S702; or, before S701, the UE may also determine whether the first candidate cell provides multicast services in the RRC non-connected state. The result of the determination may be S701, or may not be S701, but the first cell provides or is providing multicast services in the RRC non-connected state.

[0164] S702: The first candidate cell sends a second message. Correspondingly, the UE receives the second message from the first candidate cell.

[0165] The second message may indicate a second frequency. The second frequency is, for example, a frequency that may provide a multicast service in an RRC non-connected state, or a cell under the second frequency may provide a multicast service in an RRC non-connected state, and the cell under the second frequency has a greater probability of providing a multicast service in an RRC non-connected state. Among them, whether a cell provides a multicast service in an RRC non-connected state can be determined based on the degree of congestion of the network, and therefore may change dynamically, for example, a cell provides a multicast service in an RRC non-connected state in a certain time period, and may not provide a multicast service in an RRC non-connected state in the next time period. Therefore, in an embodiment of the present application, the second frequency is a frequency that "may" provide a multicast service in an RRC non-connected state, that is, the second frequency may not be a frequency that "certainly can" provide a multicast service in an RRC non-connected state. The second frequency may include one or more frequencies, and the one or more frequencies may include the frequency of the first candidate cell and / or the frequency of other cells other than the first candidate cell. The other cells may include cells provided by the network device corresponding to the first candidate cell and / or cells provided by other network devices other than the network device.

[0166] S703: The UE enters an RRC connected state in the first candidate cell according to the second message (or according to the second frequency) or does not reside in the first candidate cell.

[0167] Among them, S703 can be implemented in different ways, which are introduced below with examples.

[0168] 1. Implementation method A.

[0169] Under implementation method A, the UE enters the RRC connection state in the first candidate cell according to the second message or the second frequency, which may include: if the second frequency includes the frequency of the first candidate cell, the UE enters the RRC connection state in the first candidate cell; or, if the second frequency does not include the frequency of the first candidate cell, the UE does not reside in the first candidate cell, for example, the UE can continue to perform cell reselection.

[0170] The second frequency is, for example, a frequency that may provide a multicast service in an RRC non-connected state. If the frequency of the first candidate cell is included in the second frequency, it indicates that the first candidate cell may provide a multicast service. In this case, although the first candidate cell does not currently provide a multicast service in an RRC non-connected state, the first candidate cell may provide a multicast service in an RRC connected state. Therefore, the UE can reside in the first candidate cell and enter an RRC connected state in the first candidate cell, so that after entering the RRC connected state, there is a greater probability of receiving the multicast service, thereby improving the success rate of the UE receiving the multicast service.

[0171] 2. Implementation method B.

[0172] Under implementation method B, the UE enters the RRC connected state in the first candidate cell according to the second message or the second frequency, which may include: if the first frequency and the second frequency have an intersection, and the intersection includes the frequency of the first candidate cell, the UE enters the RRC connected state in the first candidate cell; or, if the first frequency and the second frequency have no intersection and / or have an intersection but the intersection does not include the frequency of the first candidate cell, the UE does not reside in the first candidate cell, for example, the UE can continue to perform cell reselection.

[0173] Optionally, in implementation B, the method may further include S704, the first cell or the second cell sends a first message, and correspondingly, the UE receives the first message. S704 occurs, for example, before S703, or before S702, or before S701. Figure 7 Take S704 occurring before S701 as an example, and take the first cell sending the first message as an example. The first message may indicate a first frequency. For an explanation of the first frequency, refer to Figure 3 S301 of the embodiment shown.

[0174] The first frequency includes one or more frequencies, and the second frequency includes one or more frequencies. The UE may determine whether the frequencies included in the first frequency and the frequencies included in the second frequency have an intersection. For example, if the first frequency includes frequencies f1, f2, and f3, and the second frequency includes frequencies f2 and f4, then the first frequency and the second frequency have an intersection, and the intersection is frequency f2. For another example, if the first frequency includes frequencies f1, f2, and f3, and the second frequency includes frequencies f4, f5, and f6, then the first frequency and the second frequency do not have an intersection.

[0175] If there is no intersection between the frequencies included in the first frequency and the frequencies included in the second frequency, the UE may not reside in the first candidate cell, for example, the UE may continue to perform cell reselection.

[0176] Alternatively, if the frequencies included in the first frequency and the frequencies included in the second frequency have an intersection, but the intersection does not include the frequency of the first candidate cell, the UE may not reside in the first candidate cell, for example, the UE may continue to perform cell reselection. For example, the first frequency includes frequencies f1, f2, and f3, and the second frequency includes frequencies f2 and f4, then the first frequency and the second frequency have an intersection, and the intersection is frequency f2, but the frequency of the first candidate cell is frequency f4, then the UE may not reside in the first candidate cell.

[0177] Alternatively, if the frequencies included in the first frequency and the frequencies included in the second frequency have an intersection, and the intersection includes the frequency of the first candidate cell, the UE can reside in the first candidate cell. For example, the first frequency includes frequencies f1, f2, and f3, and the second frequency includes frequencies f2 and f4, then the first frequency and the second frequency have an intersection, the intersection is frequency f2, and the frequency of the first candidate cell is frequency f2, then the UE can reside in the first candidate cell.

[0178] The first frequency is a frequency determined by the first cell or the second cell to provide a multicast service in an RRC non-connected state. The multicast service provided by the cell under the first frequency is likely to be a multicast service that the UE is interested in or is relatively important to the UE. If the first frequency and the second frequency have an intersection, the service provided by the cell under the frequency corresponding to the intersection may be a multicast service that the UE is interested in or is relatively important to the UE. If the intersection includes the frequency of the first candidate cell, it indicates that the first candidate cell may provide these multicast services. In this case, although the first candidate cell does not currently provide a multicast service in an RRC non-connected state, the first candidate cell may provide a multicast service in an RRC connected state. Therefore, the UE can reside in the first candidate cell and enter the RRC connected state in the first candidate cell, so that after entering the RRC connected state, it can have a greater probability of receiving the multicast service, which improves the success rate of the UE receiving the multicast service, and also makes the UE have a greater probability of obtaining the multicast service that the UE is interested in or is relatively important to the UE.

[0179] If the UE enters the RRC connected state in the first candidate cell, optionally, the UE may receive the multicast service in the first candidate cell in the RRC connected state.

[0180] Optionally, the first message described in the embodiment of the present application is, for example, an RRC release message from the first cell, and the UE may be released to the RRC non-connected state by the RRC release message; the second message described in the embodiment of the present application is, for example, an MCCH message from the first candidate cell (the MCCH message in the embodiment of the present application may also be referred to as a multicast MCCH message, etc., without limitation to the name), or a system message from the first candidate cell. The MCCH message may be understood as a message carried by MCCH. The system message is, for example, a SIB, such as SIB x, where x is, for example, one of the values ​​22, 23, 24, 25, 26, etc.

[0181] Alternatively, the first message described in the embodiment of the present application is, for example, an MCCH message from the first cell or the second cell; the second message described in the embodiment of the present application is, for example, an MCCH message from the first candidate cell.

[0182] Alternatively, the first message described in the embodiment of the present application is, for example, a system message from the first cell or the second cell; the second message described in the embodiment of the present application is, for example, a system message from the first candidate cell. The system message from the first cell or the second cell is, for example, a SIB, such as SIB x, where x is, for example, one of the values ​​of 22, 23, 24, 25, 26, etc.; the implementation of the system message from the first candidate cell is similar.

[0183] If the first message is a system message, an optional implementation of the first message indicating the first frequency is that the first message may indicate the correspondence between the first frequency and the MBS frequency selection area ID (FSAI). If the first frequency includes multiple frequencies, the first message may indicate the FSAI corresponding to each of the multiple frequencies. The FSAI and the MBS session may be in a one-to-one correspondence, which is equivalent to the system message not indicating the MBS session, but indicating the correspondence between the frequency and the FSAI.

[0184] Optionally, for the cell reselection process of the UE, a first threshold value may also be set, and the first threshold value is a number threshold value, for example, the first threshold value may also be called the maximum number of backoffs or the maximum number of reselections or the maximum number of selections, etc., and there is no restriction on the name. The first threshold value may be understood as the number threshold value of the number of times the UE selects a candidate cell from the candidate cell list. For example, during a cell reselection process (the cell reselection process before the UE performs the residence is considered as a cell reselection process, during which the UE may perform one or more processes of selecting a candidate cell from the cell reselection list), if the number of times the candidate cell is selected from the candidate cell list is greater than or equal to the first threshold value, the UE may reside in the candidate cell selected last time. For example, it is understood that the UE selects a candidate cell from the cell candidate list for the Nth time, N is greater than or equal to the first threshold value, and the candidate cell selected this time still cannot reside. At this time, the UE may stop the cell reselection, even if the candidate cell selected this time still does not meet the conditions (for specific conditions, please refer to the introduction of any one or more of the three aforementioned cell reselection methods), the UE can still reside in the candidate cell selected this time. In this way, the probability of the UE entering a cell reselection dead loop can be reduced, and the UE can resume the normal working process. Optionally, the candidate cell finally selected by the UE may not be within the effective range, but may meet other residency conditions such as cell reselection conditions. Otherwise, if the UE resides in a candidate cell with poor signal quality, the UE may be unable to perform the communication process.

[0185] The first threshold value may be configured by a network device, such as a network device corresponding to the first cell, a network device corresponding to the second cell, or a network device corresponding to other cells. For example, the network device may configure the first threshold value for the UE through information such as a system message, an RRC release message, or an RRC reconfiguration message. Alternatively, the first threshold value may also be predefined through a protocol, or may also be preconfigured in the UE, or may also be configured by the UE itself.

[0186] In the embodiment of the present application, although the first candidate cell does not currently provide multicast services in the RRC non-connected state, it can be known through the judgment process of the UE that the first candidate cell is likely to provide multicast services in the RRC connected state. Therefore, the UE can reside in the first candidate cell and enter the RRC connected state in the first candidate cell, so that after entering the RRC connected state, it can have a greater probability of receiving multicast services, thereby improving the success rate of the UE receiving multicast services. If the UE determines that the first candidate cell does not currently provide multicast services in the RRC non-connected state and does not make any judgment, but directly enters the RRC connected state, then if the frequency of the first candidate cell is not included in the frequency that may provide multicast services, even if the UE enters the RRC connected state, it may not be able to receive the multicast service. It can be seen that the method provided by the embodiment of the present application can improve the probability of the UE receiving multicast services.

[0187] Figure 3 The embodiment shown is Figure 7 The embodiments shown can be applied in combination. For example, the UE can first Figure 3 The method provided in the embodiment shown resides in the first candidate cell. If it is determined that the first candidate cell does not provide a multicast service in the RRC non-connected state, the method may continue to be performed. Figure 7 The method provided by the embodiment shown. Alternatively, Figure 3 The embodiment shown is Figure 7 The illustrated embodiments may not be combined but may be used individually.

[0188] Figure 8 A schematic diagram of the structure of a communication device provided in an embodiment of the present application is given. The communication device 800 may be Figure 3 or Figure 7 The circuit system of the UE described in the embodiment shown is used to implement the method corresponding to the UE in the above method embodiment. For example, one circuit system is a chip system.

[0189] The communication device 800 includes at least one processor 801. The processor 801 can be used for internal processing of the device to implement certain control processing functions. Optionally, the processor 801 includes instructions. Optionally, the processor 801 can store data. Optionally, different processors can be independent devices, can be located in different physical locations, and can be located on different integrated circuits. Optionally, different processors can be integrated into one or more processors, for example, integrated on one or more integrated circuits.

[0190] Optionally, the communication device 800 includes one or more memories 803 for storing instructions. Optionally, data may also be stored in the memory 803. The processor and the memory may be provided separately or integrated together.

[0191] Optionally, the communication device 800 includes a communication line 802 and at least one communication interface 804. Since the memory 803, the communication line 802 and the communication interface 804 are all optional, Figure 8 Indicated by dotted lines.

[0192] Optionally, the communication device 800 may further include a transceiver and / or an antenna. The transceiver may be used to send information to other devices or receive information from other devices. The transceiver may be referred to as a transceiver, a transceiver circuit, an input / output interface, etc., and is used to implement the transceiver function of the communication device 800 through an antenna. Optionally, the transceiver includes a transmitter and a receiver. Exemplarily, the transmitter may be used to generate a radio frequency signal from a baseband signal, and the receiver may be used to convert the radio frequency signal into a baseband signal.

[0193] The processor 801 may include a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

[0194] The communication link 802 may include a pathway to transmit information between the above-mentioned components.

[0195] The communication interface 804 uses any transceiver-like device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), wired access networks, etc.

[0196] The memory 803 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 803 may exist independently and be connected to the processor 801 via the communication line 802. Alternatively, the memory 803 may also be integrated with the processor 801.

[0197] The memory 803 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 801. The processor 801 is used to execute the computer-executable instructions stored in the memory 803, thereby realizing Figure 3 or Figure 7 The steps performed by the UE in the illustrated embodiment.

[0198] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0199] In a specific implementation, as an embodiment, the processor 801 may include one or more CPUs, such as Figure 8 CPU0 and CPU1 in.

[0200] In a specific implementation, as an embodiment, the communication device 800 may include multiple processors, such as Figure 8 801 and processor 805 in the embodiment of the present invention. Each of these processors may be a single-CPU processor or a multi-CPU processor. The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0201] when Figure 8When the device shown is a chip, for example, a chip of a UE, the chip includes a processor 801 (may also include a processor 805), a communication line 802 and a communication interface 804, and optionally, the chip may include a memory 803. Specifically, the communication interface 804 may be an input interface, a pin or a circuit, etc. The memory 803 may be a register, a cache, etc. The processor 801 and the processor 805 may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of the program of the communication method of any of the above embodiments.

[0202] The embodiment of the present application can divide the functional modules of the device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation. For example, in the case of dividing each functional module according to each function, Fig. 9 Schematic diagram of a device, the device 900 may be the UE involved in the above-mentioned various method embodiments, or a chip in the UE. The device 900 includes a processing unit 902 and a transceiver unit 901.

[0203] It should be understood that the device 900 can be used to implement the steps performed by the UE in the communication method of the embodiment of the present application, and the relevant features can refer to the above Figure 3 or Figure 7 The embodiments shown will not be described in detail here.

[0204] Optional, Fig. 9 The functions / implementation processes of the transceiver unit 901 and the processing unit 902 can be Figure 8 The processor 801 in the embodiment calls the computer execution instruction stored in the memory 803 to implement. Or, Fig. 9 The function / implementation process of the processing unit 902 in Figure 8 The processor 801 in the embodiment calls the computer execution instruction stored in the memory 803 to implement, Fig. 9 The function / implementation process of the transceiver unit 901 can be Figure 8 It is implemented by the communication interface 804 in.

[0205] Optionally, when the device 900 is a chip or a circuit, the function / implementation process of the transceiver unit 901 can also be implemented by a pin or a circuit. Optionally, the transceiver unit 901 may include a sending unit and / or a receiving unit, the sending unit is used to implement the sending function, and the receiving unit is used to implement the receiving function; or, the transceiver unit 901 may be an integral module that can implement the sending function and / or the receiving function. Optionally, the transceiver unit 901 may be implemented by a transceiver.

[0206] The present application also provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is executed, the method performed by the UE in the aforementioned method embodiment is implemented. In this way, the functions described in the above embodiments can be implemented in the form of software functional units and sold or used as independent products. Based on this understanding, the technical solution of the present application can be essentially or in other words, the part that contributes or the part of the technical solution can be embodied in the form of a software product, which 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 method described in each embodiment of the present application. Storage media include: various media that can store program codes, such as USB flash drives, mobile hard drives, ROM, RAM, magnetic disks, or optical disks.

[0207] 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 the method executed by the UE in any of the aforementioned method embodiments.

[0208] An embodiment of the present application also provides a processing device, including a processor and an interface; the processor is used to execute the method executed by the UE involved in any of the above method embodiments.

[0209] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may 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 may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may 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 (e.g., a solid state disk (SSD)), etc.

[0210] The various illustrative logic units and circuits described in the embodiments of the present application can be implemented or operated by a general-purpose processor, a digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or any combination of the above. The general-purpose processor can be a microprocessor, and optionally, the general-purpose processor can also be any conventional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration.

[0211] The steps of the method or algorithm described in the embodiments of the present application can be directly embedded in the hardware, the software unit executed by the processor, or the combination of the two. The software unit can be stored in RAM, flash memory, ROM, erasable programmable read-only memory (erasable programmable read-only memory, EPROM), EEPROM, register, hard disk, removable disk, CD-ROM or other storage media of any form in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Optionally, the storage medium can also be integrated into the processor. The processor and the storage medium can be arranged in an ASIC, and the ASIC can be arranged in a terminal device. Optionally, the processor and the storage medium can also be arranged in different components in the terminal device.

[0212] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0213] The contents of the various embodiments of the present application may refer to each other. If there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0214] It is understandable that in the embodiment of the present application, the UE may perform some or all of the steps in the embodiment of the present application, and these steps or operations are only examples. In the embodiment of the present application, other operations or variations of various operations may also be performed. In addition, the various steps may be performed in different orders presented in the embodiment of the present application, and it is possible that not all operations in the embodiment of the present application need to be performed.

Claims

1. A communication method, characterized in that: The method comprises: Receiving a radio resource control (RRC) release message from the first cell, wherein the RRC release message is used to release the first device to an RRC non-connected state to receive a multicast service, and the RRC release message is also used to indicate a first frequency; Entering the RRC unconnected state based on the RRC release message; If a first candidate cell under the first frequency is included in the effective range corresponding to the first frequency, the cell resides in the first candidate cell.

2. The method according to claim 1, characterized in that: The method further comprises: In the RRC unconnected state, a first multicast service is received in the first candidate cell.

3. The method according to claim 1 or 2, characterized in that: The RRC release message is also used to indicate the priority of the first frequency, and the priority of the first frequency is used by the first device to reselect a cell for receiving a multicast service in the RRC non-connected state.

4. The method according to any one of claims 1 to 3, characterized in that: The effective range is used to indicate a cell or area that provides the multicast service in the RRC non-connected state at the first frequency.

5. The method according to any one of claims 1 to 4, characterized in that: The RRC release message is also used to indicate the validity range.

6. The method according to any one of claims 1 to 5, characterized in that: The method further comprises: The first frequency is set as the highest priority frequency.

7. The method according to any one of claims 1 to 6, characterized in that: If a first candidate cell at the first frequency is included in a valid range corresponding to the first frequency, and resides before the first candidate cell, the method further includes: measuring the first candidate cell; It is determined according to the measurement result that the first candidate cell meets the cell reselection condition.

8. The method according to any one of claims 1 to 6, characterized in that: If the first candidate cell at the first frequency is included in the effective range corresponding to the first frequency, before camping on the first candidate cell, the method further includes: measuring the first candidate cell; If the first candidate cell at the first frequency is included in the effective range corresponding to the first frequency, residing in the first candidate cell includes: if the first candidate cell at the first frequency is included in the effective range corresponding to the first frequency, determining whether the first candidate cell meets the cell reselection condition according to the measurement result; if the first candidate cell meets the cell reselection condition, residing in the first candidate cell.

9. The method according to any one of claims 1 to 6, characterized in that: If a first candidate cell at the first frequency is included in the effective range corresponding to the first frequency, residing in the first candidate cell includes: If a first candidate cell at the first frequency is included in the effective range corresponding to the first frequency, measuring the first candidate cell; If it is determined according to the measurement result that the first candidate cell meets the cell reselection condition, the cell resides in the first candidate cell.

10. The method according to any one of claims 1 to 9, characterized in that: The method further comprises: If the first candidate cell under the first frequency is not included in the effective range corresponding to the first frequency, the first candidate cell is not retained.

11. The method according to claim 10, characterized in that The method further comprises: If the number of times the candidate cell is selected is greater than or equal to the first threshold, the cell stays in the candidate cell selected last time.

12. A communication method, characterized in that: The method comprises: Determining that the first candidate cell does not provide a multicast service in an RRC non-connected state; receiving a second message from the first candidate cell, where the second message is used to indicate a second frequency; If the second frequency includes the frequency of the first candidate cell, an RRC connected state is entered in the first candidate cell.

13. The method according to claim 12, characterized in that The second message is also used to indicate the priority of the second frequency, and the priority of the second frequency is used by the first device to perform cell reselection for receiving multicast services in the RRC non-connected state.

14. The method according to claim 12 or 13, characterized in that The method further comprises: If the second frequency does not include the frequency corresponding to the first candidate cell, the first candidate cell is not retained.

15. The method according to claim 12 or 13, characterized in that If the second frequency includes the frequency of the first candidate cell, entering the RRC connected state in the first candidate cell includes: If the first frequency and the second frequency have an intersection, and the intersection includes the frequency of the first candidate cell, when the first candidate cell enters the RRC connection state, the first frequency is the frequency indicated by the first message received in the source cell.

16. The method according to any one of claims 12 to 15, characterized in that: The method further comprises: If the number of times the candidate cell is selected is greater than or equal to the first threshold, the candidate cell selected last time enters the RRC connected state.

17. The method according to any one of claims 12 to 16, characterized in that: The first message is an RRC release message or a multicast broadcast service control channel MCCH message, and the second message is an MCCH message; or, The first message is an RRC release message or a system message, and the second message is a system message.

18. A communication device, characterized in that: The communication device comprises a processing unit and a transceiver unit, wherein the processing unit is coupled to the transceiver unit to execute the method according to any one of claims 1 to 11, or execute the method according to any one of claims 12 to 17.

19. A communication device, characterized in that: The communication device includes a processor and a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the communication device performs the method as described in any one of claims 1 to 11, or the communication device performs the method as described in any one of claims 12 to 17.

20. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store 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 11, or the computer is caused to execute the method according to any one of claims 12 to 17.

21. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is run on a computer, the computer is caused to execute the method according to any one of claims 1 to 11, or the computer is caused to execute the method according to any one of claims 12 to 17.

22. A chip system, characterized in that: The chip system comprises: A processor and an interface, wherein the processor is used to call and run instructions from the interface, and when the processor executes the instructions, the method according to any one of claims 1 to 11 is implemented, or the method according to any one of claims 12 to 17 is implemented.

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