WO2022183933A1

WO2022183933A1 - Communication method, and device

Info

Publication number: WO2022183933A1
Application number: PCT/CN2022/077276
Authority: WO
Inventors: 姚楚婷; 李兆俊
Original assignee: 华为技术有限公司
Priority date: 2021-03-02
Filing date: 2022-02-22
Publication date: 2022-09-09
Also published as: CN115002872A

Abstract

The present application relates to a communication method, and a device. The method comprises: during the process of network selection, a terminal device obtaining first indication information, wherein the first indication information is used for indicating that the terminal device has suffered a radio link failure event in a network corresponding to the first indication information; and the terminal device selecting a network according to the first indication information. By means of first indication information, a network with a better signal quality can be selected to the greatest extent, and the probability of the terminal device always residing in a network with a poor signal is reduced, thereby improving the communication quality of the terminal device.

Description

A communication method and device

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application with the application number 202110230394.X and the application name "a communication method, terminal and network equipment" submitted to the State Intellectual Property Office of China on March 2, 2021, the entire content of which is approved by Reference is incorporated in this application; this application claims the priority of a Chinese patent application filed on April 15, 2021, with the application number of 202110405669.9 and the application title of "a communication method and device" with the State Intellectual Property Office of China, all of which are The contents are incorporated herein by reference.

technical field

The present application relates to the field of communication technologies, and in particular, to a communication method and device.

Background technique

Before performing services, the terminal device needs to search for network signals, and then select the corresponding public land mobile network (PLMN) to perform subsequent registration and communication processes in the selected PLMN.

In the process of selecting a PLMN, the access-stratum (AS) layer of the terminal device is responsible for searching for network signals, and the non-access stratum (NAS) layer of the terminal device is responsible for selecting the PLMN. In the process of selecting a PLMN, the NAS layer will preferentially select the last registered PLMN (registerd PLMN, RPLMN) residing in the terminal device, that is, the RPLMN is the last registered PLMN of the terminal device.

For some Internet of things (IoT) devices, they are generally in a static state, for example, they will be fixed in a certain area, and the network coverage may not be very good at the location where they are located. When an IoT device is registered for a certain time, the signal of a certain PLMN may meet the registration requirements, so the IoT device is registered with the PLMN. However, the signal of the PLMN may be unstable, causing the IoT device to lose coverage after registration, and the IoT device will re-select the network when the coverage is lacking. However, in the process of re-selecting the network, according to the above introduction, the IoT device will still prefer to reside in the PLMN. This may cause the signal of the IoT device to be in a poor state for a long time, affecting the communication of the IoT device.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a communication method and device, which are used to improve the communication quality of a terminal device.

In a first aspect, a first communication method is provided, and the method can be executed by a terminal device, or by a larger device including the terminal device, or by a chip system or other functional module, the chip system or functional module can realize the terminal device. Function. The method includes: in the process of selecting a network, a terminal device obtains first indication information, where the first indication information is used to indicate that a radio link failure event has occurred to the terminal device in a network corresponding to the first indication information ; the terminal device selects a network according to the first indication information.

In this embodiment of the present application, if a radio link failure (radio link failure, RLF) event occurs in a certain network, the terminal device may add first indication information for the network. Therefore, when the terminal device selects the network, it can make the selection according to the first indication information. For example, the terminal device can increase the selection threshold, or the terminal device can ignore the network with the first indication information when selecting, so as to try to select a network with a better signal quality. A good network reduces the probability that the terminal device always resides on the network with poor signal, and improves the communication quality of the terminal device.

With reference to the first aspect, in a first optional implementation manner of the first aspect, the method further includes: the NAS layer of the terminal device determines that the first network corresponds to the first indication information, and the first The network is the last registered network of the terminal device. The terminal device selects the network according to the first indication information, for example, the AS layer of the terminal device selects the network according to the first indication information, or the NAS layer of the terminal device selects the network according to the first indication information. If the NAS layer of the terminal device selects the network according to the first indication information, the NAS layer of the terminal device may select the network according to the first indication information when it is determined that the first network corresponds to the first indication information. The first network is, for example, any one of the networks to be selected, or the first network is, for example, any network for which the NAS layer of the UE has received an identifier from the AS layer of the UE, or the first network is, for example, the network where the UE was last registered ( For example, the last RPLMN of the UE). According to the existing network selection method, the UE has a high probability to select the latest RPLMN. If the signal quality of the RPLMN is poor, the UE may fall into a coverage hole. Therefore, in this embodiment of the present application, the first network is, for example, the latest RPLMN of the UE. If the RPLMN carries the first indication information, the UE can select a network according to the first indication information. Through these implementations, the inertial selection of the UE is broken. The selection method of the latest RPLMN can make the UE select a network with better signal quality as far as possible.

With reference to the first aspect or the first optional implementation manner of the first aspect, in a second optional implementation manner of the first aspect, the terminal device selects a network according to the first indication information, including: The NAS layer of the terminal device selects the second network from the networks to be selected according to the first threshold and the first indication information. The NAS layer of the terminal device selects the network according to the first indication information, and there may be different ways, for example, one way is to select the network according to the first threshold and the first indication information.

With reference to the second optional implementation manner of the first aspect, in the third optional implementation manner of the first aspect, the NAS layer of the terminal device selects the to-be-selected according to the first threshold and the first indication information. Selecting the second network from the networks of the terminal device includes: the NAS layer of the terminal device selects the second network from the networks to be selected. Wherein, the NAS layer of the terminal device determines, according to a first method, whether a network having the first indication information in the to-be-selected network is optional, and determines, according to a second method, that the network to be selected does not have any network whether the network of the first indication information is optional; or, the NAS layer of the terminal device determines whether all the networks in the to-be-selected network are optional according to the first method; the first method and the first threshold Relatedly, the second manner is independent of the first threshold, and the first threshold is used by the terminal device to select a network in the presence of the first indication information. It can be understood that, for the network having the first indication information, a first threshold may be additionally introduced to reduce the probability that the UE selects a network with poor signal quality. For networks that do not have the first indication information, the UE may not have an RLF event in these networks, so the signal quality of the UE in these networks may not be too bad. Therefore, there is no need to introduce additional first thresholds for these networks. This can reduce the judgment process of the UE and improve the efficiency of network selection. Alternatively, for all networks to be selected, a first threshold is additionally introduced to determine whether the network can be selected. This selection method is more strict, and it is more helpful to select a network with better signal quality.

With reference to the first aspect, in a fourth optional implementation manner of the first aspect, the terminal device selects a network according to the first indication information, including: the NAS layer of the terminal device selects from the networks to be selected The second network, where the to-be-selected network includes a network that does not have the first indication information. The network with the first indication information is the network where the UE has experienced an RLF event. If the UE selects such a network, there may be a risk of poor signal. Therefore, in this way, the NAS layer of the UE can ignore the network with the first indication information when selecting, that is, the UE may not select the network with the first indication information. Select the network with better signal to improve the communication quality of the UE. Moreover, in this way, the number of networks that the UE needs to determine whether to select a network can be reduced when performing network selection, which can improve the efficiency of the network selection by the UE.

In combination with the first aspect or any optional embodiment from the first optional embodiment of the first aspect to the fourth optional embodiment of the first aspect, in the fifth optional embodiment of the first aspect In an optional implementation manner, obtaining the first indication information by the terminal device includes: in the case that the measured value of the first cell corresponding to the third network is less than or equal to the second threshold, the AS layer of the terminal device determines that the terminal device Whether a radio link failure event has occurred in the third network, wherein the terminal device meets the cell selection criteria of the first cell; if the terminal device has a radio link failure event in the third network , the AS layer of the terminal device sends the measurement value of the first cell corresponding to the third network and the identifier of at least one network to the NAS layer of the terminal device, and sends at least one network corresponding to the at least one network. One of the first indication information, the at least one network includes all or part of the network corresponding to the first cell, and the at least one network includes the third network. If the NAS layer of the terminal device selects the network according to the first indication information, the NAS layer of the terminal device can obtain the first indication information from the AS layer of the terminal device. If the measured value of the first cell corresponding to the third network is less than or equal to the second threshold, it indicates that the signal quality of the first cell is not very good. In this case, the AS layer of the terminal device can determine whether the third network has occurred RLF event, if an RLF event has occurred, the first indication information can be sent to the NAS layer of the terminal device, so that the NAS layer of the terminal device can identify the networks where the RLF event has occurred in the terminal device, so as to consider it when selecting a network.

With reference to the fifth optional implementation manner of the first aspect, in a sixth optional implementation manner of the first aspect, the method further includes: measuring in the first cell corresponding to the third network When the value is greater than the second threshold, the AS layer of the terminal device sends the identifier of the third network to the NAS layer of the terminal device, and indicates that the third network is a high-quality network. If the measured value of the first cell corresponding to the third network is greater than the second threshold, it indicates that the signal quality of the first cell is better, so the AS layer of the terminal device can mark the third network as a high-quality network, so as to be less than the signal quality. good network.

With reference to the first aspect, in a seventh optional implementation manner of the first aspect, obtaining the first indication information by the terminal device includes: in the case where the measured value of the first cell corresponding to the third network is less than or equal to the second threshold Next, the AS layer of the terminal device determines whether the terminal device has experienced a radio link failure event in the third network, wherein the terminal device meets the cell selection criteria of the first cell; if the terminal device meets the cell selection criteria of the first cell The device has experienced a radio link failure event in the third network, and the AS layer of the terminal device obtains the first indication information of the third network. If the AS layer of the terminal device selects the network according to the first indication information, the AS layer of the terminal device can obtain the first indication information according to this method.

With reference to the seventh optional implementation manner of the first aspect, in the eighth optional implementation manner of the first aspect, the terminal device selects a network according to the first indication information, including: The AS layer does not send the identification of the third network to the NAS layer of the terminal device, wherein the identification of the third network is not sent for the NAS layer of the terminal device not to select the third network when selecting a network network. If the terminal device has an RLF event on a certain network, the AS layer of the terminal device does not send the identifier of the network to the NAS layer of the terminal device. For the NAS layer of the terminal device, if the identifier of a certain network is not received from the AS layer of the terminal device, the network cannot be selected. In this way, the probability of the terminal device selecting a network with poor signal can be reduced. .

In combination with the first aspect or any one of the optional embodiments from the first optional embodiment of the first aspect to the eighth optional embodiment of the first aspect, in the ninth optional embodiment of the first aspect In an optional embodiment, the method further includes: after selecting the second network, sending second indication information to the network device, where the second indication information is used to indicate that the terminal device is in the second cell of the fourth network A wireless link failure event has occurred. After the terminal device successfully selects a certain network, the information of the network and the corresponding cell where the terminal device has experienced an RLF event can be sent to the network device, and the information can be used for network optimization. For example, the network device may increase the threshold of the second cell to stay on the network. If the threshold for camping on the network is increased, if the terminal device wants to camp in the second cell, the measured value of the first parameter needs to be higher, which also increases the difficulty of the terminal device in selecting the second cell, that is to say , the number of terminal devices that can be selected to the second cell can be reduced. For another example, the network device may configure a first threshold for at least one terminal device, and through the first threshold, the difficulty in selecting the second cell for the terminal device can be improved. The second cell is a cell where some terminal devices have experienced RLF, indicating that the signal quality of the second cell is not very good, so by improving the difficulty of terminal devices to select the second cell, fewer terminal devices can select the second cell. , so that the terminal equipment can try to camp on the cell with better signal quality.

In combination with the first aspect or any one of the optional embodiments from the first optional embodiment of the first aspect to the ninth optional embodiment of the first aspect, in the tenth optional embodiment of the first aspect In a selected embodiment, the method further includes: after selecting the second network, sending the identification of the second network and the identification of the third cell where the terminal device is located to the network device; receiving data from the network device information of the M networks, where the M networks are the networks in the area where the third cell is located, and M is a positive integer; when selecting a network again, search for an available network according to the information of the M networks. For example, if the terminal device roams to an unfamiliar area, the terminal device performs a blind search in the unfamiliar area. For example, if the terminal device selects the second network through blind search, the terminal device registers with the second network and resides in a third cell under the second network. In this case, the terminal device may send the identity of the second network and the identity of the third cell to the network device through the second network. The network device can determine the information of one or more networks in the area where the third cell is located, for example, can determine the frequency (frequency band or frequency point) information of one or more networks in the area where the third cell is located, and can use the determined The information of these networks is sent to the terminal device. For example, when the terminal device is powered off and then powered on, or the terminal device recovers from lack of coverage, or the terminal device performs periodic network selection, the terminal device needs to search for the network again. Then, when the terminal device needs to search for the network, it can search according to the information of the M networks. For example, the information of the M networks includes the frequencies of the M networks, then the terminal device can search for some or all of the frequencies of the M networks. The search is performed on frequencies, and for frequencies other than the frequencies of the M networks, the terminal device may no longer search, or the number of frequencies to be searched may be reduced.

In combination with the first aspect or any one of the optional embodiments from the first optional embodiment of the first aspect to the tenth optional embodiment of the first aspect, in the eleventh optional embodiment of the first aspect In an optional implementation manner, the first network is a PLMN or an NPN. This embodiment of the present application does not limit the concept of "network".

In a second aspect, a second communication method is provided, and the method can be executed by a network device, or executed by a system-on-chip or other functional modules, and the system-on-chip or functional modules can implement the functions of the network device. Exemplarily, the network device is an access network device, such as a base station. The method includes: receiving second indication information from a terminal device, where the second indication information is used to indicate that a radio link failure event has occurred to the terminal device in a second cell of a fourth network; executing a first processing manner; wherein , the first processing manner includes: reconfiguring cell selection criteria for the second cell; and/or configuring a first threshold for at least one terminal device, where the first threshold is used by the terminal device to determine whether the selected cell can be selected the second district.

With reference to the second aspect, in a first optional implementation manner of the second aspect, the method further includes: receiving, from the terminal device, an identifier of the second network and an identifier of a third cell where the terminal device is located; Send information of M networks to the terminal device, where the M networks are networks in the area where the third cell is located, and M is a positive integer.

Regarding the technical effects brought about by the second aspect or various optional embodiments, reference may be made to the introduction to the technical effects of the first aspect or corresponding embodiments.

In a third aspect, a third communication method is provided, and the method can be executed by a network device, or executed by a chip system or other functional module, and the chip system or the functional module can realize the function of the network device. Exemplarily, the network device is an access network device, such as a base station. The method includes: receiving, from a terminal device, an identifier of a second network and an identifier of a third cell where the terminal device is located; and sending information of M networks to the terminal device, where the M networks are where the third cell is located , where M is a positive integer.

With reference to the third aspect, in a first optional implementation manner of the third aspect, the method further includes: receiving second indication information from a terminal device, where the second indication information is used to indicate that the terminal device is in A radio link failure event has occurred in the second cell of the fourth network; a first processing method is performed; wherein, the first processing method includes: reconfiguring cell selection criteria for the second cell; and/or, for at least one The terminal device configures a first threshold, where the first threshold is used by the terminal device to determine whether the second cell can be selected.

Regarding the technical effects brought about by the third aspect or various optional embodiments, reference may be made to the introduction to the technical effects of the first aspect or corresponding embodiments.

In a fourth aspect, a communication device is provided. The communication apparatus may be the terminal device described in any one of the above-mentioned first to third aspects. The communication device has the functions of the above-mentioned terminal device. The terminal equipment is, for example, a base station, or a baseband device in a base station. In an optional implementation manner, the communication device includes a baseband device and a radio frequency device. In another optional implementation manner, the communication apparatus includes a processing unit (sometimes also called a processing module) and a transceiver unit (sometimes also called 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 the sending unit (sometimes also called the sending module), and when the transceiver unit realizes the receiving function, it can be called the receiving unit (sometimes also called receiving module). The sending unit and the receiving unit can be the same functional module, which is called a transceiver unit, and this functional module can realize the sending function and the receiving function; or, the sending unit and the receiving unit can be different functional modules, and the transceiver unit is the The collective name for functional modules.

Wherein, the processing unit is configured to obtain first indication information in the process of selecting a network, where the first indication information is used to indicate that the terminal device has experienced a wireless link in a network corresponding to the first indication information road failure event;

The processing unit is further configured to select a network according to the first indication information.

In an optional implementation manner, the communication apparatus further includes a storage unit, and the processing unit is configured to be coupled to the storage unit and execute programs or instructions in the storage unit to enable the communication apparatus The function of the terminal device described in any one of the first to third aspects above is performed.

In a fifth aspect, a communication device is provided. The communication apparatus may be the network device described in any one of the first to third aspects above. The communication device has the function of the above-mentioned network device. The network equipment is, for example, a base station, or a baseband device in a base station. In an optional implementation manner, the communication device includes a baseband device and a radio frequency device. In another optional implementation manner, the communication apparatus includes a processing unit (sometimes also called a processing module) and a transceiver unit (sometimes also called a transceiver module). For the implementation of the transceiver unit, reference may be made to the introduction of the fourth aspect.

Wherein, the transceiver unit (or the receiving unit) is configured to receive second indication information from the terminal device, where the second indication information is used to indicate that the terminal device has occurred in the second cell of the fourth network. A radio link failure event; the processing unit is configured to execute the first processing mode. The first processing manner includes: reconfiguring cell selection criteria for the second cell; and/or configuring a first threshold for at least one terminal device, where the first threshold is used by the terminal device to determine whether the Second district.

Alternatively, the transceiver unit (or, the receiving unit) is configured to receive, from the terminal device, the identifier of the second network and the identifier of the third cell where the terminal device is located; the transceiver unit (or the sending unit) ), used to send information of M networks to the terminal device, where the M networks are networks in the area where the third cell is located, and M is a positive integer.

In an optional implementation manner, the communication apparatus further includes a storage unit, and the processing unit is configured to be coupled to the storage unit and execute programs or instructions in the storage unit to enable the communication apparatus The function of the network device described in any one of the first to third aspects above is performed.

In a sixth aspect, a computer-readable storage medium is provided, the computer-readable storage medium is used to store a computer program or instruction, and when it is executed, the method performed by the terminal device or the network device in the above aspects is realized. .

In a seventh aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the methods of the above aspects to be implemented.

Description of drawings

FIG. 1 is a schematic diagram of an application scenario of an embodiment of the present application;

2 to 4 are flowcharts of several communication methods provided by embodiments of the present application;

FIG. 5 is a schematic block diagram of a communication device provided by an embodiment of the present application;

FIG. 6 is a schematic block diagram of a terminal device provided by an embodiment of the present application;

FIG. 7 is a schematic block diagram of a network device provided by an embodiment of the present application.

Detailed ways

In order to make the objectives, technical solutions and advantages of the embodiments of the present application more clear, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Hereinafter, some terms or concepts in the embodiments of the present application will be explained, so as to facilitate the understanding of those skilled in the art.

In this embodiment of the present application, a terminal device is a device with a wireless transceiver function, which may 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 (such as a built-in wireless device in the above-mentioned device). , communication modules, modems, or systems on a chip, etc.). The terminal device is used to connect people, things, machines, etc., and can be widely used in various scenarios, such as but not limited to the following scenarios: cellular communication, device-to-device communication (device-to-device, D2D), vehicle-to-everything (vehicle to everything, V2X), machine-to-machine/machine-type communications (M2M/MTC), Internet of things (internet of things, IoT), virtual reality (virtual reality, VR) , Augmented reality (AR), industrial control (industrial control), unmanned driving (self driving), telemedicine (remote medical), smart grid (smart grid), smart furniture, smart office, smart wear, smart transportation , terminal equipment for smart city, drone, robot and other scenarios. The terminal equipment may sometimes be referred to as user equipment (UE), a terminal, an access station, a UE station, a remote station, a wireless communication device, a user equipment, or the like. For the convenience of description, in the embodiments of this application, the terminal device is described by taking the UE as an example.

The network device in the embodiment of the present application includes, for example, one or more of the following: an access network device, a core network device, or a server set by an operator. The access network device is a device with a wireless transceiver function, and is used to communicate with the terminal device. The access network equipment includes but is not limited to the base station (BTS, Node B, eNodeB/eNB, or gNodeB/gNB), the transmission reception point (TRP), the third generation partnership project (3rd Generation partnership project, 3GPP) subsequent evolution of base stations, access nodes in wireless fidelity (Wi-Fi) systems, wireless relay nodes, wireless backhaul nodes, etc. The base station may be: a macro base station, a micro base station, a pico base station, a small base station, a relay station, and the like. Multiple base stations may support the aforementioned networks of the same access technology, or may support the aforementioned networks of different access technologies. A base station may contain one or more co-sited or non-co-sited transmission reception points. The network device may also be a wireless controller, a centralized unit (centralized unit, CU), and/or a distributed unit (distributed unit, DU) in a cloud radio access network (cloud radio access network, CRAN) scenario. The network device can also be a server, a wearable device, or a vehicle-mounted device. For example, a network device in a vehicle to everything (V2X) technology can be a road side unit (RSU). The following description will be given by taking the access network device as a base station as an example. The base station can communicate with the terminal equipment, and can also communicate with the terminal equipment through the relay station. A terminal device can communicate with multiple base stations in different access technologies. The core network equipment is used to implement functions such as mobility management, data processing, session management, policy and charging. The names of devices implementing core network functions in systems with different access technologies may be different, which are not limited in this embodiment of the present application. Taking the 5G system as an example, the core network equipment includes: access and mobility management function (AMF), session management function (session management function, SMF), policy control function (policy control function, PCF) or User plane function (user plane function, UPF), etc. The server set by the operator can be used to manage one or more types of terminal devices. For example, the IoT device manager (IoT device manager), as a server set by the operator, can manage the IoT devices covered by the operator. .

In the embodiment of the present application, the communication device for implementing 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, and the device may be installed in the network device. In the technical solutions provided by the embodiments of the present application, the technical solutions provided by the embodiments of the present application are described by taking the device for realizing the function of the network device being a network device as an example.

In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular nouns or plural nouns", that is, "one or more". "At least one" means one or more, and "plurality" means two or more. "And/or", which describes the association relationship of the associated objects, indicates that there can be three kinds of relationships, for example, A and/or B, which can indicate: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A, B can be singular or plural. The character "/" generally indicates that the associated objects are an "or" relationship. For example, A/B, means: A or B. "At least one item(s) below" or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s). 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.

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. For example, the first network and the second network may be the same network or different networks, and this name does not indicate the location, corresponding parameters, priority or importance of the two networks. different. In addition, the numbering of the steps in the various embodiments introduced in this application is only for distinguishing different steps, and is not used to limit the sequence of steps. For example, S201 may occur before S202, or may occur after S202, or may also occur simultaneously with S202.

In the process of selecting a PLMN, the AS layer of the UE is responsible for searching for network signals, and the NAS layer of the UE is responsible for selecting the PLMN.

The AS layer of the UE mainly performs the process of cell search. The AS layer searches for cells on some frequency points. For a searched cell, if the broadcast information of the cell can be read, the AS layer can obtain the cell selection criteria included in the broadcast information, and obtain the PLMN corresponding to the cell. information. The cell selection criteria included in the broadcast information of a cell includes the conditions that need to be satisfied to select the cell. For example, the UE judges whether the cell is allowed to camp according to the broadcast information from the cell (that is, judges whether the cell is in the bar state, if the cell is in the bar state, it is not allowed to camp, otherwise it is allowed to camp) , if the cell is allowed to camp, the UE determines whether the reference signal receiving power (RSRP) and the reference signal receiving quality (RSRQ) measured by the UE in the cell are greater than that of the cell. The threshold provided by the system information block (SIB), the SIB is, for example, SIB1, if the RSRP and RSRQ measured by the UE in the cell are greater than the threshold provided by the SIB of the cell, the UE can select the cell , otherwise the UE cannot select the cell. That is to say, through the cell selection criterion, it can be determined whether the signal quality of the cell is good enough to support the UE to camp in the cell.

For a cell for which the UE satisfies the cell selection criteria, if the signal strength of the cell is higher than a threshold (for example, in a long term evolution (LTE) system, an NR system, or a narrowband internet of things (NB-IoT) )) system, the threshold is -110dBm), then the AS layer marks the PLMN corresponding to the cell as a high-quality PLMN (HQ PLMN), and sends the PLMN ID and the mark of the HQ PLMN to the NAS layer. For a cell where the UE meets the cell selection criteria, if the signal strength of the cell is lower than the threshold, the AS layer can send the PLMN ID corresponding to the cell and the RSRP of the cell to the NAS layer. RSRP measured by the cell. However, if the UE does not meet the cell selection criteria of a cell, the AS layer of the UE does not need to report the information of the PLMN corresponding to the cell (for example, the identity of the PLMN corresponding to the cell, etc.) to the NAS layer of the UE.

The NAS layer of the terminal device may trigger the NAS layer to select a PLMN in the following two cases: the first case is power-on or recovery from lack of coverage, and the second case is a periodic network selection attempt. The first situation can be understood as the UE needs to find a suitable PLMN access when it is powered on or after recovering from a state of lack of coverage. In the second case, in order for the UE to select a PLMN according to the operator's configuration, the UE needs to periodically search to determine whether there is a PLMN with a higher priority. The network selection process in these two cases is described separately below.

1. The network selection process in the first case.

When the NAS layer of the UE starts to select a PLMN, it usually searches for the RPLMN first, and after finding the RPLMN, the NAS layer determines whether the RPLMN is available (or optional). As mentioned above, the AS layer of the UE will report some PLMN IDs to the NAS layer, then if the NAS layer receives a PLMN ID from the AS layer, no matter whether the PLMN has the HQ PLMN flag or does not have the HQ PLMN flag, it indicates that The PLMN is available. The NAS layer can determine whether the RPLMN is available in this way, and if the RPLMN is available, the NAS layer selects the RPLMN for resident without making other judgments. If the RPLMN is unavailable, the NAS layer can traverse the following lists in order of priority: (equivalent) home PLMN list ((equivalent) HPLMN list), User Controlled PLMN Selector with Access Technology) list, Operator Controlled PLMN Selector with Access Technology list. These lists can be pre-configured in a subscriber identity module (SIM) card by the operator, or the operator can also deliver these lists to the UE after the UE joins the network, or the operator can send the lists to the UE after the UE joins the network update information. Wherein, the (equivalent) HPLMN list includes the information of the HPLMN of the UE, and/or includes the information of the equivalent PLMN of the HPLMN of the UE. The equivalent PLMNs of the HPLMN of the UE are, for example, some PLMNs configured by the operator of the HPLMN. For example, the operator of the HPLMN has signed a contract with the operator to which these PLMNs belong, and these PLMNs can be used as the equivalent PLMNs of the HPLMN. The User Controlled PLMN Selector with Access Technology list is the access PLMN list configured by the user, and the list includes some PLMN information configured by the user. The Operator Controlled PLMN Selector with Access Technology list is the access PLMN list configured by the operator, and the list includes some PLMN information configured by the operator.

The NAS layer sequentially determines whether the PLMNs in the above list are available in order of priority. For example, for a PLMN in a certain list, the NAS layer can determine whether the PLMN is available, and the determination method can refer to the foregoing introduction. If it is determined that the PLMN is available, the NAS layer may select the PLMN without subsequent determination. If all PLMNs in these lists are unavailable, the NAS layer selects according to the information reported by the AS layer. For example, the PLMN ID reported by the AS layer includes a PLMN ID marked with an HQ RPLMN, and the NAS layer can select a PLMN corresponding to the PLMN ID from these PLMN IDs to reside there. If the PLMN ID reported by the AS layer does not include the PLMN ID with the HQ RPLMN flag, then the NAS layer sorts according to the RSRP corresponding to each PLMN ID reported by the AS layer, and selects the PLMN corresponding to the PLMN ID with the highest RSRP value. to stay.

In this case, the RPLMN, the PLMN in the above list, and the PLMN whose ID has been reported by the AS layer are all considered to be the PLMN to be selected.

2. The network selection process in the second case.

The NAS layer of the UE can maintain the HPLMN control timer. When the timer expires, the NAS layer can scan the high-priority PLMN, that is, the UE will periodically scan the high-priority PLMN to determine whether it can access the high-priority PLMN. Level PLMN. In the second case, the NAS layer will not give priority to RPLMN, but will traverse the following lists in priority order: (equivalent) HPLMN list, User Controlled PLMN Selector with Access Technology list, Operator Controlled PLMN Selector with Access Technology list. For example, for a PLMN in a certain list, the NAS layer may determine whether the PLMN is available, and the determination method may refer to the foregoing introduction. If it is determined that the PLMN is available, the NAS layer may select the PLMN without subsequent determination. And if all PLMNs in these lists are unavailable, the UE continues to camp on the RPLMN. In this case, both the RPLMN and the PLMN in the above list are considered to be the PLMN to be selected.

Although the NAS layer does not give priority to the RPLMN in this case, the ID of the RPLMN may also exist in one or more of the above lists, so the UE will actually consider whether to reside in the RPLMN when traversing the above list. That is to say, in the second case, there is a high probability that the UE will continue to camp on the RPLMN.

Currently, UEs with lower capabilities such as IoT also use the same network selection method described above. In some regions (e.g. Europe), some low-cost and low-capacity IoT UEs usually have the following characteristics:

These UEs are often in a stationary state;

These UEs may be located in remote locations with limited coverage;

These UEs need relatively stable data connections as part of the measurement and control network, and these UEs do not necessarily only transmit small amounts of data;

These UEs may be distributed anywhere in the world.

For example, IoT UEs can be set up in a reservoir, and these IoT UEs can be placed on the bottom of the water to monitor the water level and can send information related to the water level to the network periodically or based on event triggers.

For some IoT UEs, there may be a form of permanent roaming, i.e. there is usually no HPLMN at the time of access. However, these IoT UEs still have an RPLMN because they will still register with a certain visited PLMN (visit PLMN, VPLMN). This type of IoT UE encounters some problems in deployment. For example, after an IoT UE registers with a PLMN, the signal of the PLMN may be unstable, causing the IoT UE to lose coverage after registration, and subsequent data transmission of the IoT UE may fail. The IoT UE can re-select the network when it lacks coverage. According to the above introduction, even if there is a network with better signal, the IoT UE will still prefer to reside in the RPLMN. This may cause the IoT UE's signal to be in a poor state for a long time, affecting the IoT UE's communication.

There may be a large number of IoT UEs. If many IoT UEs are in this state, additional maintenance may be required for these IoT UEs, and such maintenance may require manual processing on site, which increases the complexity of maintenance. , which also makes operators need to pay higher operating costs and reduces the commercial benefits of machine-to-machine (M2M).

In view of this, the technical solutions of the embodiments of the present application are provided. In this embodiment of the present application, if the terminal device has experienced a communication failure in a certain network, such as an RLF event, the first indication information may be added to the network. Therefore, when the NAS layer of the terminal device selects the network, it can select according to the first indication information. For example, the terminal device can increase the selection threshold, or the terminal device can ignore the network with the first indication information when selecting, so as to try to select the network with the first indication information. A network with better signal quality reduces the probability that a terminal device always resides on a network with poor signal quality, and improves the communication quality of the terminal device.

Referring to FIG. 1 , it is a schematic diagram of an application scenario of an embodiment of the present application. In FIG. 1 , the UE can communicate with the network device 1, and the cell 1 provided by the network device 1 is a cell covered by the PLMN1, for example, the PLMN1 is the RPLMN and/or the HPLMN of the UE. In addition, the cell 2 provided by the network device 2 is a neighboring cell of the UE, and is a cell covered by the PLMN2. It can be seen that, if the UE is at the edge of cell 1, the coverage of PLMN1 to the UE may not be very good. For example, the UE may lose the coverage of PLMN1, so the UE can reselect the PLMN. Or even if the UE does not lose coverage, the UE may select the PLMN if it is just powered on, or the UE may periodically select the PLMN. When the UE selects a PLMN, both PLMN1 and PLMN2 can be within the optional range.

The network device in FIG. 1 is, for example, an access network device, and the access network device is, for example, a base station. The access network equipment corresponds to different equipment in different systems, for example, in a 4G system, it may correspond to an eNB, and in a 5G system, it corresponds to an access network equipment in 5G, such as a gNB. Of course, the technical solutions provided in the embodiments of the present application can also be applied to future mobile communication systems, so the access network equipment in FIG. 1 can also correspond to network equipment in future mobile communication systems. The embodiments of the present application take the access network device being a base station as an example. In fact, referring to the foregoing introduction, the access network device may also be a device such as an RSU.

The methods provided by the embodiments of the present application are described below with reference to the accompanying drawings. In the drawings corresponding to the various embodiments of the present application, all optional steps are represented by dotted lines. The UEs described in the various embodiments of this application are, for example, IoT UEs, or may also be common UEs. The "network" described in the various embodiments of the present application is, for example, a PLMN or a non-public network (non-public network, NPN), or other networks, for example, the first network is the first PLMN or the first NPN, the second The network is the second PLMN or the second NPN, etc.; the network (for example, RPLMN) that the UE recently registered in the various embodiments of this application is, for example, PLMN1 in the network architecture shown in FIG. 1 ; The technical solutions described above can all be applied to the network architecture shown in FIG. 1 . For example, the UE described in the various embodiments of the present application is, for example, the UE in the network architecture shown in FIG. 1 .

It should be noted that some operations of the UE described in the various embodiments of this application, such as searching for a cell, reading the system information of the cell, determining whether the network corresponding to the cell is a high-quality network, or determining whether the UE is in the network corresponding to the cell. RLF events, etc. have occurred. In the following description, the AS layer of the UE is used as an example to perform these operations, but in practical applications, it is not limited to this. For example, these operations can also be performed by other protocol layers of the UE. In addition, These operations can be performed by one protocol layer or by multiple protocol layers. Similarly, other operations of the UE described in the various embodiments of this application, such as selecting a network, etc., are all performed by the NAS layer of the UE as an example, but the actual application is not limited to this. Other protocol layers perform these operations, and in addition, these operations may be performed by one protocol layer or by multiple protocol layers.

An embodiment of the present application provides a communication method. Please refer to FIG. 2 , which is a flowchart of the method.

S201. When selecting a network, the AS layer of the UE searches for a cell in a specified frequency band. For example, the AS layer of the UE may perform a full-frequency search in frequency band (band) 1 according to a certain frequency interval, and the frequency interval is, for example, 100 kHz or 10 kHz. The network selection this time is, for example, a periodic selection, or a selection when the UE is powered on, or a selection after the UE recovers from lack of coverage.

S202. If the AS layer of the UE searches for a cell, it can read the system information of the cell.

For example, if the AS layer of the UE searches for the first cell, it can read the system information of the first cell, for example, the system information includes system information block 1 (system information block 1, SIB1). SIB1 may include the cell selection criteria of the first cell, and the cell selection criteria of the first cell may indicate the conditions that the UE needs to meet to select the first cell. For example, the cell selection criteria of the first cell include the criteria that the UE needs to meet to select the first cell. resident network threshold. In addition, the SIB1 may further include an identifier of a network corresponding to the first cell, where the identifier of the network is, for example, an identity number of the network, and the first cell may correspond to one or more networks. The identity number of the network includes, for example, the ID of the network (for example, the network is a PLMN, then the identity number of the network includes the ID of the PLMN, or the network is an independent non-public network (stand-alone non-public network, SNPN), then The identity number of the network includes the ID of the SNPN), or the closed access group (CAG) ID of the network, or the human-readable network name (HRNN) of the network, etc. .

S203. The AS layer of the UE determines whether the UE satisfies the cell selection criteria of the first cell. If the AS layer of the UE determines that the UE meets the cell selection criteria of the first cell, S204 may be executed, and if the AS layer of the UE determines that the UE does not meet the cell selection criteria of the first cell, S201 may be executed continuously.

S204. The AS layer of the UE determines whether the measurement value of the first cell corresponding to the third network is greater than the second threshold. If the measured value of the first cell corresponding to the third network is greater than the second threshold, perform S205, and if the measured value of the first cell corresponding to the third network is less than or equal to the second threshold, perform S207.

The measurement value of the first cell, for example, is the value of the first parameter obtained by the AS layer of the UE measuring the reference signal from the first cell, and the first parameter may indicate the signal quality of the UE, for example, the first parameter is RSRP or RSRQ et al. As described above, the first cell may correspond to one or more networks, and the third network is, for example, any network corresponding to the first cell. If the first cell corresponds to multiple networks, the UE may separately measure reference signals from different networks in the first cell, and thus may obtain measurement values corresponding to different networks in the first cell. Since the UE processes the measurement values of different networks in a similar manner, the measurement values obtained by the UE in the first cell and corresponding to the third network are taken as an example for introduction.

The second threshold is, for example, a threshold specified by a protocol, or a threshold configured by a network device, or a threshold determined by the UE itself. For example, in the LTE system, the NR system, or the NB-IoT system, the second threshold is -110dbm, or may be other values.

S205. If the measured value of the first cell corresponding to the third network is greater than the second threshold, the AS layer of the UE marks the third network as a high quality (high quality, HQ) network.

Optionally, the AS layer of the UE may determine whether an RLF event has occurred in the third network for the UE. That is to say, although the third network is currently a high-quality network, the UE can still determine whether the UE has an RLF event in the third network. Regarding whether the UE has experienced an RLF event in the third network, there may be various ways of determining, and the content of this part will be introduced in the subsequent steps.

S206, the AS layer of the UE sends the identifier of the third network to the NAS layer of the UE, and indicates that the third network is a high-quality network (for example, the AS layer of the UE sends high-quality indication information to the NAS layer of the UE, and the high-quality indication information may be indicating that the network corresponding to the second indication information is a high-quality network), correspondingly, the NAS layer of the UE receives the identifier of the third network from the AS layer of the UE, and determines that the third network is a high-quality network (for example, the NAS layer of the UE After receiving the high-quality indication information from the AS layer of the UE, it can be determined that the third network is a high-quality network). The identifier of the third network is, for example, the ID of the third network.

Optionally, if the AS layer of the UE determines that the UE has experienced an RLF event in the third network, then in S206, the AS layer of the UE sends the identifier of the third network to the NAS layer of the UE and indicates that the third network is In addition to the high-quality network, first indication information may also be sent to the NAS layer of the UE, where the first indication information may indicate that the UE has experienced an RLF event in the network corresponding to the first indication information. After the NAS layer of the UE receives the first indication information (it is also considered that the NAS layer of the UE obtains the first indication information), it can be determined that an RLF event has occurred in the third network for the UE.

For example, if the identifier of a certain network sent by the AS layer of the UE to the NAS layer of the UE corresponds to the first indication information, it can indicate that the UE has experienced an RLF event in this network, and if the AS layer of the UE sends the NAS layer of the UE to the NAS layer of the UE If the identifier of a certain network does not correspond to the first indication information, it may indicate that the UE has not experienced an RLF event in the network. For another example, if the identifier of a certain network sent by the AS layer of the UE to the NAS layer of the UE corresponds to the first indication information, it can indicate that the UE has not experienced an RLF event in the network, and if the AS layer of the UE sends the NAS layer of the UE to the NAS layer of the UE If the identifier of a certain network sent by the layer does not correspond to the first indication information, it may indicate that the UE has experienced an RLF event in the network.

Alternatively, the identifier of the network sent by the AS layer of the UE to the NAS layer of the UE may correspond to the first indication information, and the first indication information may indicate that the UE has experienced an RLF event in the network, or indicate that the UE has not experienced RLF in the network. event. For example, the first indication information occupies 1 bit (bit), if the value of this bit is "1", it indicates that the UE has an RLF event in the network; if the value of this bit is "0", it indicates that the UE is in the No RLF events have occurred on this network.

Of course, there are other implementation manners for the first indication information, which all fall within the protection scope of the embodiments of the present application.

S207. If the measured value of the first cell corresponding to the third network is less than or equal to the second threshold, the AS layer of the UE determines whether the UE has experienced an RLF event in the third network.

If the UE meets the cell selection criteria of the first cell, but the measurement value obtained by the UE by measuring the reference signal from the third network in the first cell is less than or equal to the second threshold, and the AS layer of the UE can read the ID, then the AS layer of the UE can determine whether the UE has an RLF event in the third network. Whether the UE has an RLF event in the third network can be determined in a variety of ways, as described in the following example.

As an optional implementation manner, if the UE has experienced X times of RLF events in the third network within the first duration, it is determined that the UE has experienced RLF events in the third network, and if the UE has experienced RLF events in the first duration If the number of occurrences of RLF events in the third network is less than X, it is determined that the UE has not experienced RLF events in the third network. X is a positive integer, and if X is greater than 1, X times are, for example, continuous X times, or may be discontinuous X times. The end moment of the first duration is, for example, the current moment, and the duration or start moment of the first duration is specified by, for example, a protocol, or configured by a network device, or determined by the UE itself. For example, one kind of starting time of the first duration is the time when the UE was powered on the last time; for another example, another kind of starting time of the first duration is the time when the UE registered to the third network for the last time; for another example, the first time Another starting time of the duration is the time when the UE first registers with the third network.

As another optional implementation manner, if an RLF event occurs in the third network after the UE initially registers with the third network, it is determined that the UE has an RLF event in the third network, and if the UE registers for the first time in the third network If no RLF event occurs in the third network after reaching the third network, it is determined that no RLF event occurs in the third network for the UE. After the UE first registered with the third network, an RLF event occurred in the third network. The RLF event may have been successfully recovered, or may not have been successfully recovered, and the event that triggers the UE to perform network selection this time may be the RLF event, or possibly not this RLF event. That is to say, as long as the UE has experienced an RLF event in the third network after initially registering with the third network, regardless of the recovery result of the RLF event, and regardless of whether the RLF event is an event that triggers this network selection, it is considered that The UE has experienced an RLF event in the third network.

Through the above two implementations, it is possible to determine the network in which the UE has experienced RLF events in the history. Since the UE has experienced RLF events in the third network in the history, it indicates that there is a risk of problems in the communication of the UE in the third network. Screening out such a network helps to reduce the probability of the UE having another RLF event.

As another optional implementation manner, if the UE has an RLF event in the third network and the RLF event recovery fails, then it is determined that the UE has an RLF event in the third network; otherwise, if the UE is in the third network If an RLF event occurs in the network, but the RLF event is successfully recovered, it is determined that the UE has not experienced an RLF event in the third network. Wherein, if the RLF event fails to recover, the RLF event may be the event that triggers this network selection. In this implementation manner, the network in which the RLF event has occurred is screened according to the current situation. The current situation can more accurately reflect the current quality of the network, thereby expanding the selection range of the UE while ensuring the communication quality of the UE as much as possible. .

It should be noted that, as described in the introduction of various embodiments above, an RLF event occurs in the third network for the UE, and the RLF event may occur in the first cell, or may occur in other cells except the first cell. occurring.

As a further optional implementation manner, if the first cell in the third network is a candidate cell of the third network, if the UE has an RLF event in other cells covered by the third network except the first cell , it can also be considered that the UE has not experienced an RLF event in the third network, and if the UE has experienced an RLF event in the first cell covered by the third network, it can be considered that the UE has experienced an RLF event in the third network. That is to say, in this case, the UE considers that the RLF event has occurred in the network only when the RLF event occurs in the candidate cell of the network. In this implementation, if a network can provide multiple cells, it can more accurately screen the network that has experienced RLF events according to the current situation. Expand the selection range of the UE under the condition of ensuring the communication quality of the UE.

S208. The AS layer of the UE determines whether the measurement value of the third network is greater than a third threshold.

Optionally, for a network where the measurement value is less than or equal to the second threshold and the UE has experienced an RLF event, a UE's AS layer screening mechanism (hereinafter also referred to as the AS layer screening mechanism) may be introduced. If the AS layer screening mechanism is introduced, after performing S207, if the UE determines that an RLF event has occurred in the third network, S208 may be performed, and if the UE determines that an RLF event has not occurred in the third network, it may not S208 is executed, but S209 is executed. Alternatively, if the screening mechanism of the AS layer is not introduced, after S207 is performed, regardless of whether the UE has an RLF event in the third network, it is not necessary to perform S208, but S209 is performed.

For example, if the UE considers that an RLF event has occurred in the network only if the RLF event occurs in the candidate cell of the network, then if the first cell is the candidate cell of the third network, the UE has the RLF event in the first cell. In the event of RLF, in S208, the AS layer of the UE may determine whether the measurement value of the first cell is greater than the third threshold. For another example, if the UE determines that the UE has experienced an RLF event in the third network through other methods described above, in S208, the AS layer of the UE may determine whether the measurement value of any cell of the UE under the coverage of the third network is greater than or equal to The third threshold, or the AS layer of the UE may determine whether the measurement value of the cell where the RLF event has occurred of the UE under the coverage of the third network is greater than the third threshold. The third threshold is specified by the protocol, or configured by the network device, or determined by the UE itself, or configured on the subscriber identity module (SIM) card or the universal subscriber identity module (USIM) card middle. The third threshold is the same as the first threshold to be introduced later, for example, the value may be the same, or the value may be different.

If the screening mechanism of the AS layer is introduced and S208 is performed, if the UE determines that the measurement value of the third network is greater than the third threshold, it may continue to perform S209, and if the UE determines that the measurement value of the third network is less than or equal to the third If the threshold is set, S209 may not be performed, but S201 may be continuously performed, that is, the UE continues to search for other cells, and judges the networks corresponding to the other cells in a similar manner as described above. Equivalently, if the screening mechanism of the AS layer is introduced, then the AS layer of the UE, by introducing a third threshold, will further screen the network where the RLF event has occurred, so as to report the network with better signal quality to the NAS layer of the UE For the network with poor signal quality (for example, the network whose measurement value is less than or equal to the third threshold), the AS layer of the UE may not report to the NAS layer of the UE, and the NAS layer of the UE will not select these networks. . This is more helpful for the UE to select a network with better signal quality, and reduces the workload of the NAS layer of the UE.

S209 , the AS layer of the UE sends the measurement value of the first cell corresponding to the third network and the identifier of at least one network to the NAS layer of the UE. The at least one network includes all or part of the network corresponding to the first cell, and the third network is one of the at least one network.

Wherein, S205-S206 and S207-S209 are two parallel schemes, and one of them can be executed according to the magnitude relationship between the measurement value of the first cell corresponding to the third network and the second threshold.

If the screening mechanism of the AS layer is introduced, if the AS layer of the UE determines that the UE has not experienced an RLF event in the third network, it can execute S209. In S209, the AS layer of the UE can send the third network to the NAS layer of the UE. The identifier of the network, and the measurement value obtained by the UE in the first cell and corresponding to the third network. At this time, at least one network is the third network. For example, if the third network is a PLMN, the AS layer of the UE sends the ID of the PLMN to the NAS layer of the UE, and sends the RSRP or RSRQ corresponding to the PLMN measured by the UE in the first cell.

If the screening mechanism of the AS layer is not introduced, then if the AS layer of the UE determines that the UE has not experienced an RLF event in the third network, in S209, the AS layer of the UE can send the identity of the third network to the NAS layer of the UE, and sending the measurement value corresponding to the third network obtained by the UE in the first cell. At this time, at least one network is the third network. For example, if the third network is a PLMN, the AS layer of the UE sends the ID of the PLMN to the NAS layer of the UE, and sends the RSRP or RSRQ corresponding to the PLMN measured by the UE in the first cell.

If the screening mechanism of the AS layer is not introduced, then if the AS layer of the UE determines that the UE has experienced an RLF event in the third network, in S209, the AS layer of the UE may send the identifier of at least one network to the NAS layer of the UE, and Send the measurement value corresponding to the third network obtained by the UE in the first cell. In addition, at least one first indication information may be sent to the NAS layer of the UE, where the at least one first indication information corresponds to at least one network, for example, one network corresponds to A first indication message. The first indication information may indicate that the UE has experienced an RLF event in the network corresponding to the first indication information. For the implementation of the first indication information, reference may be made to the foregoing introduction. When the NAS layer of the UE receives at least one first indication information (it is also considered that the NAS layer of the UE obtains the first indication information, or it is regarded that the NAS layer of the UE obtains at least one first indication information), it can be determined that the UE is at least A network has experienced an RLF event. For example, the AS layer of the UE sends the first indication information of the third network to the NAS layer of the UE, so that the NAS layer of the UE can make it clear that the RLF event has occurred in the third network for the UE. For example, if the first cell corresponds to multiple networks, and one of the multiple networks is the third network, because the UE temporarily determines that the UE has experienced an RLF event in the third network, it does not involve other networks corresponding to the first cell. network, so the AS layer of the UE can only send the identity of the third network to the NAS layer of the UE without sending the identity of other networks. Or, if the first cell corresponds to multiple networks, and one of the multiple networks is the third network, because the UE has experienced an RLF event in the third network, if the RLF event occurred in the first cell, then the UE RLF events may also occur (or have occurred) in other networks corresponding to the first cell. Therefore, the AS layer of the UE can send the identities of all or part of the networks corresponding to the first cell to the NAS layer of the UE (sent by the UE). The identification of the third network includes the identification of the third network).

If the AS layer of the UE only sends the identifier of the third network to the NAS layer of the UE, then in S209, the AS layer of the UE may send the measurement value of the first cell corresponding to the third network, the measurement value of the third network corresponding to the first cell to the NAS layer of the UE in S209 the identifier, and the first indication information corresponding to the third network. Alternatively, if the AS layer of the UE sends the identifiers of all the networks or part of the network corresponding to the first cell to the NAS layer of the UE, then in S209, the AS layer of the UE may send the NAS layer of the UE the identifiers of the first cell corresponding to the third network The measured value of the at least one network, and at least one first indication information corresponding to the at least one network.

S210. The UE obtains the first indication information.

S210 may be regarded as obtaining the first indication information by the AS layer of the UE, or may be regarded as obtaining the first indication information by the NAS layer of the UE. If S210 is regarded as the AS layer of the UE obtaining the first indication information, then in S205, if the AS layer of the UE determines whether the UE has experienced an RLF event in the third network, and the determination result is that the UE has experienced RLF in the third network event, it is considered that the AS layer of the UE has obtained the first indication information, then this step in S205 can be regarded as being included in S210. Similarly, if in S207, if the AS layer of the UE determines whether the UE has experienced an RLF event in the third network, and the determination result is that the UE has experienced an RLF event in the third network, it is considered that the AS layer of the UE has obtained the first RLF event. indicating information, then this step in S207 can be regarded as being included in S210.

If S210 is regarded as the NAS layer of the UE obtaining the first indication information, for example, the NAS layer of the UE may receive the first indication information from the AS layer of the UE through S209, or may receive the first indication information from the AS layer of the UE through S206, When the NAS layer of the UE receives the first indication information from the AS layer of the UE, it is considered that the NAS layer of the UE obtains the first indication information, for example, the NAS layer of the UE can obtain one or more first indication information. In addition, if the AS layer of the UE sends the first indication information corresponding to the third network to the NAS layer of the UE in S206, the NAS layer of the UE receives the first indication information corresponding to the third network from the AS layer in S206, This step is considered to be included in S210. Similarly, if the AS layer of the UE sends at least one first indication information to the NAS layer of the UE in S209, the NAS layer of the UE receives at least one first indication information from the AS layer in S209, and this step is deemed to be included in S210. middle. In addition to this, all steps in which the NAS layer of the UE receives the first indication information from the AS layer of the UE are deemed to be included in S210.

S211. The UE selects a network according to the first indication information.

S211 may be regarded as the AS layer of the UE selecting the network according to the first indication information, and it may also be regarded as the NAS layer of the UE selecting the network according to the first indication information. If S211 is regarded as the UE's AS layer selecting the network according to the first indication information, then in S205, if the UE's AS layer determines whether the UE has an RLF event in the third network and S206 is executed, it is regarded as the UE's The AS layer selects a network according to the first indication information. That is to say, this selection method is that, if the third network is a high-quality network, no matter whether the UE has an RLF event in the third network, the AS layer of the UE can store the information related to the third network (for example, the third network's identity, etc.) sent to the NAS layer of the UE. Similarly, if S208 is executed, if the AS layer of the UE determines that the measurement value of the third network is greater than the third threshold, S209 can be executed, and if the AS layer of the UE determines that the measurement value of the third network is less than or equal to the third threshold , S209 is not performed, which is also regarded as the AS layer of the UE selects the network according to the first indication information. That is to say, this selection method is that the AS layer of the UE performs screening by introducing a third threshold, so as to report the network with better signal quality to the NAS layer of the UE for selection, and for the network with poor signal quality, the UE's The AS layer may not report to the NAS layer of the UE, and the NAS layer of the UE will not select these networks.

If S211 is considered as the NAS layer of the UE selects the network according to the first indication information, the NAS layer of the UE selects the network according to the first indication information, and there are many different selection methods, which are described below through different steps.

S2111 , the NAS layer of the UE selects a second network from the networks to be selected, and the networks to be selected include networks that do not have the first indication information. For example, the network to be selected in S2111 is called the first type of network, then the first type of network belongs to the second type of network. Introduce the network to be selected. It can be considered that in the method of S2111, the network with the first indication information is removed from the second type of network, and the selection is made from the remaining networks (that is, the first type of network), for example, in the remaining networks One network is selected, and for convenience of description, the selected network is referred to as the second network.

Taking the UE powering on or recovering from lack of coverage as an example, and taking the "network" as a "PLMN" as an example, the second type of network may include the RPLMN, the PLMNs in the aforementioned list, and the PLMNs whose IDs are reported by the AS layer. When the NAS layer of the UE makes the selection, it still traverses these PLMNs in sequence according to the priority order introduced above. For example, when traversing a PLMN, the NAS layer of the UE can determine whether the PLMN has the first indication information. If the PLMN has the first indication information, the NAS layer of the UE ignores the PLMN and continues to traverse the next PLMN. , and continue to determine whether the next PLMN carries the first indication information; and if the PLMN does not carry the first indication information, the NAS layer of the UE determines whether the PLMN is optional (for example, if the NAS layer of the UE is from the AS of the UE If the PLMN is optional, the NAS layer of the UE selects the PLMN and no longer traverses other PLMNs, and if the PLMN is not optional, the UE Continue to traverse the next PLMN, and continue to determine whether the next PLMN carries the first indication information. And so on until the UE's NAS layer selects the second network, or until the UE selection fails. That is to say, the removal of the first type of network from the second type of network is not a unified removal, but the UE will ignore the network with the first indication information in the process of traversing the network, so it is considered that the first type of network has been removed. .

Optionally, if the selection fails, the UE may traverse the second-type network without removing the first-type network again in priority order, which can reduce the probability that the UE has no network to select due to coverage problems.

The network with the first indication information is the network where the UE has experienced an RLF event. If the UE selects such a network, there may be a risk of poor signal. Therefore, in this way, the NAS layer of the UE can ignore the network with the first indication information when selecting, that is, the UE may not select the network with the first indication information. Select the network with better signal to improve the communication quality of the UE. Moreover, in this way, the number of networks that the UE needs to determine whether to select a network can be reduced when performing network selection, which can improve the efficiency of the network selection by the UE.

S2112. The NAS layer of the UE selects the second network from the networks to be selected according to the first threshold and the first indication information. The network to be selected in S2111 is the first type of network, and the network to be selected in S2112 is the second type of network described in S2111. The second type of network includes the network to be selected that was introduced when introducing the network selection process of the NAS layer of the UE in several cases. That is, in S2112, no network is excluded from the second type of network, and the second The class network is used as the network to be selected. It can be considered that in the manner of S2112, the network of the second type is selected, for example, a network is selected from the network of the second type. For the convenience of description, the selected network is referred to as the second network.

S2112 may have several different implementations, which are described below with examples.

1. In the first embodiment, the NAS layer of the UE determines whether the network to be selected is optional according to the first method.

That is, for any one of the networks to be selected, the NAS layer of the UE determines whether the network is optional according to the first method. The first manner is related to the first threshold. For example, the first manner includes: if the measurement value of a network is greater than the first threshold, the network is selectable; otherwise, the network is not selectable. The first threshold is specified by, for example, a protocol, or configured by a network device, or can also be determined by the UE itself, or configured in a SIM card or a USIM card.

If the measured value of a network is greater than the first threshold, the NAS layer of the UE may select this network. Of course, the premise is that the NAS layer of the UE receives the identity of the network from the AS layer of the UE. If the NAS layer of the UE does not receive the identity of the network from the AS layer of the UE, even if the measured value of the network is greater than the first threshold, it cannot be select. From this point of view, it can also be considered that the first method includes: the measurement value of a network is greater than the first threshold, and the NAS layer of the UE receives the identifier of the network from the AS layer of the UE, then the network is optional, otherwise the network cannot be used. select.

Taking the UE powering on or recovering from lack of coverage as an example, and taking the "network" as "PLMN" as an example, the network to be selected is the second type of network, and the second type of network may include RPLMN, PLMN in the aforementioned list, and AS The layer reported the ID of the PLMN. When the NAS layer of the UE makes the selection, it still traverses these PLMNs in sequence according to the priority order introduced above. For example, when the NAS layer of the UE traverses to a certain PLMN, it can determine whether the measurement value of the PLMN is greater than the first threshold, and determine whether the ID of the PLMN is received from the AS layer of the UE. If the measured value of the PLMN is greater than the first threshold, and the NAS layer of the UE has received the ID of the PLMN from the AS layer of the UE, the UE can select the PLMN without traversing other PLMNs; and if the measured value of the PLMN is less than or equal to the first threshold, and/or the NAS layer of the UE does not receive the ID of the PLMN from the AS layer of the UE, then the PLMN is not selectable, and the NAS layer of the UE continues to traverse the next PLMN, and continues to determine the measurement of the next PLMN Whether the value is greater than the first threshold, and whether the ID of the next PLMN is received from the AS layer of the UE. And so on, until the network is selected, or until the network to be selected is traversed.

If the network to be selected has not been selected after traversing the network to be selected, the UE may traverse the network to be selected again, and during this traversal process, no additional first threshold is added to the network. For example, when traversing to a certain PLMN, the NAS layer of the UE can determine whether the ID of the PLMN is received from the AS layer of the UE. If the NAS layer of the UE has received the ID of the PLMN from the AS layer of the UE, the UE can select the PLMN without traversing other PLMNs; and if the NAS layer of the UE has not received the ID of the PLMN from the AS layer of the UE, Then the PLMN is not selectable, and the NAS layer of the UE continues to traverse the next PLMN, and continues to determine whether the ID of the next PLMN is received from the AS layer of the UE. And so on until the selection reaches the network, or until the selection fails.

For the first embodiment, it can be understood that, for all networks to be selected, a first threshold is additionally introduced to determine whether the network can be selected. This selection method is more strict, and it is more helpful to select a network with better signal quality.

2. In the first embodiment, the NAS layer of the UE determines whether the network with the first indication information in the network to be selected is optional according to the first method, and the NAS layer of the UE determines that the network to be selected does not have the network according to the second method. Whether the network of the first indication information is optional. In other words, the second embodiment includes: for the networks to be selected that have the first indication information, the NAS layer of the UE determines whether these networks are optional according to the first method; and for the networks to be selected that do not have the first indication A network indicating information, the NAS layer of the UE determines whether these networks are optional according to the second method.

That is to say, for a network with the first indication information in the network to be selected, the NAS layer of the UE determines whether the network is selectable according to the first method, and for a network in the to-be-selected network without the first indication information The network indicating the information and the NAS layer of the UE both determine whether the network is optional according to the second method. For the introduction of the first method, please refer to the previous section. The second manner is irrelevant to the first threshold. For example, the second manner includes: if the NAS layer of the UE receives an identifier of a network from the AS layer of the UE, the network is selectable; otherwise, the network is not selectable.

Taking the UE powering on or recovering from lack of coverage as an example, and taking the "network" as "PLMN" as an example, the network to be selected is the second type of network, and the second type of network may include RPLMN, PLMN in the aforementioned list, and AS The layer reported the ID of the PLMN. When the NAS layer of the UE makes the selection, it still traverses these PLMNs in sequence according to the priority order introduced above. For example, when the NAS layer of the UE traverses to a certain PLMN, it can determine whether the PLMN carries the first indication information. If the PLMN carries the first indication information, the NAS layer of the UE determines whether the measurement value of the PLMN is greater than the first indication information. threshold, and determine whether the PLMN's ID is received from the UE's AS layer. If the measured value of the PLMN is greater than the first threshold, and the NAS layer of the UE has received the ID of the PLMN from the AS layer of the UE, the UE can select the PLMN without traversing other PLMNs; and if the measured value of the PLMN is less than or equal to the first threshold, and/or the NAS layer of the UE does not receive the ID of the PLMN from the AS layer of the UE, then the PLMN is not selectable, and the NAS layer of the UE continues to traverse the next PLMN, and continues to determine whether the next PLMN has a There is a first indication message. Alternatively, if the NAS layer of the UE determines that the PLMN does not carry the first indication information, the NAS layer of the UE determines whether the ID of the PLMN is received from the AS layer of the UE. If the NAS layer of the UE has received the ID of the PLMN from the AS layer of the UE, the UE can select the PLMN without traversing other PLMNs; and if the NAS layer of the UE has not received the ID of the PLMN from the AS layer of the UE, Then the PLMN is not selectable, and the NAS layer of the UE continues to traverse the next PLMN, and continues to determine whether the next PLMN carries the first indication information. And so on, until the network is selected, or until the network to be selected is traversed.

If the network to be selected has not been selected after traversing the network to be selected, the UE may traverse the network to be selected again, and in this traversal process, no additional first threshold is added to the network with the first indication information. For example, when traversing to a certain PLMN, the NAS layer of the UE can determine whether the ID of the PLMN is received from the AS layer of the UE. If the NAS layer of the UE has received the ID of the PLMN from the AS layer of the UE, the UE can select the PLMN without traversing other PLMNs; and if the NAS layer of the UE has not received the ID of the PLMN from the AS layer of the UE, Then the PLMN is not selectable, and the NAS layer of the UE continues to traverse the next PLMN, and continues to determine whether the ID of the next PLMN is received from the AS layer of the UE. And so on until the selection reaches the network, or until the selection fails.

For the second embodiment, it can be understood that, for the network having the first indication information, a first threshold may be additionally introduced to reduce the probability that the UE selects a network with poor signal quality. For networks that do not have the first indication information, the UE may not have an RLF event in these networks, so the signal quality of the UE in these networks may not be too bad. Therefore, there is no need to introduce additional first thresholds for these networks. This can reduce the judgment process of the UE and improve the efficiency of network selection.

S2111 and S2112 are two different implementations (of course, S2112 includes two different implementations). For example, if the NAS layer of the UE determines that the first network does not correspond to the first indication information, S2111 may be executed, and if the NAS layer of the UE determines that the first network corresponds to the first indication information, any one of the implementations of S2112 may be executed Way. Alternatively, regardless of whether the first network corresponds to the first indication information, S2111 can be executed without executing S2112. Alternatively, regardless of whether the first network corresponds to the first indication information, S2112 can be executed without executing S2111.

The first network is, for example, any network in the second type of networks, or the first network is, for example, any network for which the NAS layer of the UE has received an identifier from the AS layer of the UE, or the first network is, for example, the network where the UE registered last time (eg UE's most recent RPLMN). According to the existing network selection method, the UE has a high probability to select the latest RPLMN. If the signal quality of the RPLMN is poor, it may fall into a coverage hole. Therefore, in this embodiment of the present application, the first network is, for example, the latest RPLMN of the UE. If the RPLMN carries the first indication information, the UE can use any one of the implementations in S2111 or S2112 to select a network, and through these implementations The method breaks the selection method of the UE's inertial selection to the latest RPLMN, and can try to make the UE select a network with better signal quality.

Optionally, if the screening mechanism of the AS layer is introduced, the NAS layer of the UE may not select the network according to the method of S2111 or S2112, but may select the network according to the existing normal method. For the existing normal method, please refer to the introduction. The related content introduced before the embodiment shown in FIG. 2 . That is to say, if the screening mechanism of the AS layer is introduced, the NAS layer of the UE can select the network in the normal way, and the NAS layer of the UE can follow the existing mechanism, so that it can better match the existing mechanism. way compatible. And when it is selected according to the existing normal method, since the AS layer of the UE does not send the identities of these networks to the NAS layer of the UE for networks whose measurement value is less than or equal to the second threshold and the UE has experienced an RLF event, the UE The NAS layer will not select these networks when selecting networks, thereby also improving the quality of the network selected by the UE and reducing the situation that the UE falls or continues to fall into coverage holes. Alternatively, even if the screening mechanism of the AS layer is introduced, the NAS layer of the UE may continue to select the network in the manner of S2111 or S2112, which is not limited in this embodiment of the present application.

In this embodiment of the present application, S201 to S209 are all optional steps, and S2111 to S2111 are also optional steps.

In this embodiment of the present application, the NAS layer of the UE (or the AS layer of the UE) may additionally add selection criteria to some or all of the networks to be selected, for example, additionally introduce a first threshold (or a third threshold), for the network to be selected Part or all of the network, respectively determine whether the measured value of the corresponding network is greater than the first threshold (or the third threshold), if the measured value of a certain network is greater than the first threshold (or the third threshold), the network can be selected, and if the measured value of a network is greater than the first threshold (or the third threshold) If the measured value of a certain network is less than or equal to the first threshold (or the third threshold), the network is not selected. Equivalently, since an RLF event has occurred in the network where the UE registered the last time, it indicates that the signal of the network registered the last time is not very good, so the UE can introduce the first threshold (or the third threshold) to select the network, and pass the first threshold (or the third threshold) try to select the network with better signal. Alternatively, the NAS layer of the UE may not consider the network with the first indication information. In this way, the probability of the UE always staying on a network with poor signal can be reduced, the communication quality of the UE is improved, and the operation and maintenance cost of the UE is also reduced. And in this way, the probability of the UE falling into or continuously falling into a coverage hole can also be reduced.

With the embodiment shown in FIG. 2 , the probability of the UE falling into or continuously falling into a coverage hole can be reduced. In addition, the embodiments of the present application provide a second communication method, in which the probability of more UEs falling into or continuing to fall into a coverage hole can be reduced through the intervention of a network device. Please refer to FIG. 3 , which is a flowchart of the method.

S301. After the UE selects the second network, the UE sends the second indication information to the network device, and correspondingly, the network device receives the second indication information from the UE. For example, the UE selects the second network through the selection method provided by the embodiment shown in FIG. 2, or the UE may not use the selection method provided by the embodiment shown in FIG. 2, but selects the second network by using the existing selection method. Second network.

For example, the UE is an IoT UE, and the network device is, for example, an IoT device manager maintained by an operator, and the UE can send the second indication information to the network device through the user. For example, the IoT device manager is jointly maintained by multiple operators, and is used to manage IoT devices covered by multiple operators; or, the IoT device manager is maintained by, for example, an operator to which the second network belongs, and is used to manage the IoT devices. Carrier-covered IoT devices.

The second indication information may indicate that the UE has experienced an RLF event in the second cell of the fourth network. That is to say, after the UE successfully selects a certain network, the information of the network and the corresponding cell in which the UE has experienced the RLF event can be sent to the network device, and the information can be used for network optimization. For example, the second indication information may include the identity of the fourth network and the identity of the second cell. The UE may have experienced an RLF event in one or more cells of the fourth network, and the second cell here may include this one or more cells. multiple neighborhoods. Optionally, the second indication information may further include information used to indicate that an RLF event occurs to the UE, for example, the second indication information includes the identity of the fourth network, the identity of the second cell, and the information used to indicate that an RLF event has occurred to the UE. information, then the network device can determine, according to the second indication information, that the UE has experienced an RLF event in the second cell of the fourth network. Alternatively, the second indication information may not include the information used to indicate that the UE has an RLF event. As long as the UE sends the network identifier and the cell identifier to the network device, the network device can determine that the UE is under the network. An RLF event has occurred in the cell. For example, the second indication information includes the identity of the fourth network and the identity of the second cell, then the network device can determine, according to the second indication information, that the UE has experienced an RLF event in the second cell of the fourth network. Alternatively, the second indication information may also include the network identifier, cell identifier, and location information of the UE in which the RLF event occurs. The location information is, for example, location information, and the network device can more accurately determine the cell in which the RLF event occurs according to the location information. cover the void location.

Optionally, the second indication information may include, in addition to information about the network where the UE fails, the network identifier and cell identifier currently selectable by the UE, or the network identifier and cell identifier that the UE has successfully selected. Then, the network device can determine, according to the second indication information, which networks are available in the current location and which networks may have problems, so as to guide the UE in subsequent network selection.

S302. The network device executes the first processing mode. By executing the first processing manner, the difficulty of selecting the second cell for the UE can be improved.

The first processing manner includes, for example, manner 1 and/or manner 2, and may also include other manners. Mode 1 and Mode 2 are described below.

Manner 1: Reconfigure the cell selection criteria for the second cell to improve the difficulty for the UE to select the second cell.

For example, the network device may negotiate with the operator corresponding to the fourth network (for example, it may negotiate with the core network device provided by the operator through message interaction) to change the cell selection criteria of the second cell, for example, it may improve the Residential network threshold of the second cell. If the threshold for camping on the network is increased, if the UE wants to camp on the second cell, the measured value of the first parameter needs to be higher, which also increases the difficulty for the UE to select the second cell. Reduce the number of UEs that can select to the second cell. The second cell is a cell where some UEs have experienced RLF, indicating that the signal quality of the second cell is not very good, so by increasing the difficulty of the UE selecting the second cell, fewer UEs will select the second cell, that is, The UE can be made to camp on a cell with better signal quality as much as possible, the probability of more UEs falling into or continuously falling into the coverage hole is reduced, and the communication quality of the UE is improved.

Manner 2: Configure a first threshold for at least one UE, where the first threshold is used by the UE to determine whether the second cell can be selected. By passing the first threshold, the difficulty for the UE to select the second cell can be improved. For example, the network device is an IoT device manager, and at least one UE includes, for example, part or all of the IoT UEs managed by the IoT device manager.

For the usage of the first threshold, reference may be made to the introduction of the embodiment shown in FIG. 2 . Configuring the first threshold for the UE is equivalent to adding additional conditions for the UE to select the second cell, which is equivalent to increasing the difficulty for the UE to select the second cell. By increasing the difficulty for UEs to select the second cell, so that fewer UEs select the second cell, it is also possible to make UEs camp on cells with better signal quality as much as possible, reducing more UEs falling into or continuously falling into coverage holes probability, and improve the communication quality of the UE.

Whether the network device adopts mode 1, mode 1, or mode 1 and mode 2 may be determined by the network device, for example, the network device may be determined according to the actual situation. For example, if multiple UEs indicate to the network device that an RLF event has occurred in the second cell of the fourth network, for example, the number of UEs that indicate to the network device that an RLF event has occurred in the second cell of the fourth network is greater than the first number , then the network device can adopt Mode 1, or adopt Mode 1 and Mode 2. Because there are a large number of UEs that have experienced RLF events in the second cell of the fourth network, the probability that the second cell has a problem is relatively high. In this case, it is reasonable to adopt method 1. Of course, in this case, way 1 and way 2 can also be used. By configuring the cell and the UE together, the configuration efficiency can be improved, so that more UEs can better achieve the goal of selecting a network with better signal quality. The first quantity is specified by a protocol, for example, or determined by the network device itself. For example, the network device may learn the total number of UEs served by the second cell, and the first number is, for example, greater than or equal to half of the total number of UEs served by the second cell.

For another example, if only a small number of UEs indicate to the network device that an RLF event has occurred in the second cell of the fourth network, for example, the number of UEs that indicate to the network device that an RLF event has occurred in the second cell of the fourth network is smaller than that of the second cell. number, then the network device can use mode 2. Because the number of UEs that have experienced RLF events in the second cell of the fourth network is relatively small, it may be a problem of these UEs themselves, while the second cell may not have a problem. For example, these UEs may be located at the edge of the second cell, causing The signal quality is poor, so Mode 2 is more reasonable in this case.

Alternatively, whether the network device adopts the mode 1, the mode 1, or the mode 1 and the mode 2 may also be specified by a protocol, etc., which is not limited in this embodiment of the present application.

In the embodiment of the present application, through the interaction between the UE and the network device, the UE can obtain more information, or can provide the network with more information for subsequent cell configuration, which can help the UE to select a more suitable network. With network participation, the probability of more UEs falling or continuing to fall into coverage holes can be reduced.

Next consider another question. If a UE roams to an unfamiliar area, the UE needs to re-search for a cell to re-register with the local network. Since the UE has not been to this area before, the UE needs to perform a blind search on an unfamiliar frequency band. For example, when a user comes to China from Europe, the home PLMN of the user's mobile phone is the PLMN provided by the European operator, and the mobile phone is currently roaming. The mobile phone needs to search for the cell of the Chinese operator for access. Since the mobile phone has not been to China before, the UE does not store the information of the local PLMN in China, so the mobile phone needs to search blindly. In addition, after the UE searches and registers with a PLMN, the UE needs to perform periodic network selection, or the UE may be powered on again or recover from lack of coverage, that is, the UE may need to face multiple search processes. . In each search process, the UE needs to search blindly on an unfamiliar frequency band. It takes a lot of time to perform a blind search on an unfamiliar frequency band, and is not conducive to the energy saving of the UE.

In view of this, the embodiment of the present application provides a third communication method, through which the time of the UE's blind search can be reduced, and the power of the UE can be saved. Please refer to FIG. 4 , which is a flowchart of the method. The process of the UE searching for the network described in the method may be performed by, for example, the AS layer of the UE, or may also be performed by other protocol layers of the UE.

S401. After selecting the second network, the UE sends the identifier of the second network and the identifier of the third cell to the network device, and correspondingly, the network device receives the identifier of the second network and the identifier of the third cell from the UE. Or, after the UE selects the second network, it sends the request information to the network device, and correspondingly, the network device receives the request information from the UE. The request information can be used to apply for information about available cells in the surrounding area. The third cell is, for example, the cell where the UE currently resides. For example, the UE selects the second network through the selection method provided by the embodiment shown in FIG. 2, or the UE may not use the selection method provided by the embodiment shown in FIG. 2, but selects the second network by using the existing selection method. Second network.

For example, the UE is an IoT UE, and the network device is, for example, an IoT device manager maintained by an operator, and the UE can send the identifier of the second network and the identifier of the third cell to the network device through the user. For example, the IoT device manager is jointly maintained by multiple operators, and is used to manage IoT devices covered by multiple operators; or, the IoT device manager is maintained by, for example, an operator to which the second network belongs, and is used to manage the IoT devices. Carrier-covered IoT devices. For example, the UE may directly send information to the network device (for example, send the identity of the second network and the identity of the third cell, or send request information), or the UE may also send information through an access network device serving the UE or The core network device sends information to the network device (for example, sending the identifier of the second network and the identifier of the third cell, or sending request information).

For example, if the UE roams to an unfamiliar area, the UE performs a blind search in the unfamiliar area. For example, if the UE selects the second network through blind search, the UE registers with the second network and camps on a third cell under the second network. In this case, the UE may send the identity of the second network and the identity of the third cell to the network device through the second network, or the UE may transmit the identity of the second network and the identity of the third cell to the access network device or core serving the UE through the second network The network equipment sends the request information, the access network equipment or the core network equipment determines the identity of the second network and the identity of the third cell where the UE is currently located, and then sends the identity of the second network and the identity of the third cell to the The network device, or the UE may send request information to the network device through the second network, and the network device determines the identity of the second network and the identity of the third cell where the UE is currently located.

S402: The network device sends the information of the M networks to the UE, and correspondingly, the UE receives the information of the M networks from the network device. The M networks are, for example, networks in the area where the third cell is located, and M is a positive integer.

After receiving the identifier of the second network and the identifier of the third cell, the network device may determine information about one or more networks in the area where the third cell is located, for example, may determine the frequency of one or more networks in the area where the third cell is located (frequency band or frequency point) information, and can send the determined information of these networks to the UE. Or, after receiving the request information, the network device may determine the third cell where the UE is located (or determine the third cell under the second network where the UE is located), so as to determine one or more areas where the third cell is located For the network information, for example, frequency information of one or more networks in the area where the third cell is located may be determined, and the determined information of these networks may be sent to the UE.

S403. When selecting a network again, the UE searches for an available network according to the information of the M networks.

For example, when the UE is powered off and then powered on, or when the UE recovers from lack of coverage, or when the UE performs periodic network selection, the UE needs to search for the network again. Then, when the UE needs to search for a network, it can search according to the information of the M networks. For example, the information of the M networks includes the frequencies of the M networks, then the UE can search for some or all of the frequencies of the M networks. A search is performed, and the UE may no longer search for frequencies other than those of the M networks, or may reduce the number of frequencies searched. In this way, the search range of the UE can be narrowed, thereby reducing the search time of the UE, which is beneficial to the energy saving of the UE. Moreover, these networks are all determined by network equipment, and the probability that the UE can search for a cell is high, so the success rate of the UE search can also be improved.

The embodiment shown in FIG. 2 , the embodiment shown in FIG. 3 and the embodiment shown in FIG. 4 may be applied in combination. For example, the UE may search for a network through the embodiment shown in FIG. 4 , select a network through the embodiment shown in FIG. 2 , and after selecting a network, may also send second indication information to the network device through the embodiment shown in FIG. 3 . Alternatively, any two of the embodiment shown in FIG. 2 , the embodiment shown in FIG. 3 and the embodiment shown in FIG. 4 may be applied in combination. For example, the embodiment shown in FIG. 2 is applied in combination with the embodiment shown in FIG. 3. For example, the UE may select a network through the embodiment shown in FIG. 2, and after selecting a network, the embodiment shown in FIG. The device sends second indication information. For another example, the embodiment shown in FIG. 2 is applied in combination with the embodiment shown in FIG. 4 , for example, the UE may search for a network through the embodiment shown in FIG. 4 and select a network through the embodiment shown in FIG. 2 . For another example, the embodiment shown in FIG. 3 is applied in combination with the embodiment shown in FIG. 4. For example, the UE can search for a network through the embodiment shown in FIG. 4, and after selecting a network, it can also use the embodiment shown in FIG. The network device sends the second indication information. Alternatively, the embodiment shown in FIG. 2 , the embodiment shown in FIG. 3 , and the embodiment shown in FIG. 4 may not be combined, but may be independently applied.

To sum up, in this embodiment of the present application, when the UE selects a network, the selection may be made according to the first indication information. For example, the UE may increase the selection threshold, or the UE may ignore the network with the first indication information when selecting, so as to try to select a network with the first indication information. Going to a network with better signal quality reduces the probability that the UE always resides on a network with poor signal quality, and improves the communication quality of the UE. Moreover, through the intervention of the network device, the search time of the UE can also be reduced, which is beneficial to the energy saving of the UE.

FIG. 5 is a schematic structural diagram of a communication apparatus 500 provided by an embodiment of the present application. The communication apparatus 500 may be the terminal device described in any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 4 , and is configured to implement the method executed by the terminal device in the foregoing method embodiments. Alternatively, the communication apparatus 500 may also be the network device described in any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 4 , for implementing the method corresponding to the network device in the foregoing method embodiments. For specific functions, refer to the descriptions in the foregoing method embodiments.

Communication device 500 includes one or more processors 501 . The processor 501 may also be referred to as a processing unit, and may implement certain control functions. The processor 501 may be a general-purpose processor or a special-purpose processor, or the like. For example, including: baseband processors, central processing units, application processors, modem processors, graphics processors, image signal processors, digital signal processors, video codec processors, controllers, memories, and/or Neural network processors, etc. The baseband processor may be used to process communication protocols and communication data. The central processing unit may be used to control the communication device 500, execute software programs and/or process data. The different processors can be stand-alone devices, or they can be integrated in one or more processors, for example, on one or more application specific integrated circuits.

Optionally, the communication apparatus 500 includes one or more memories 502 for storing instructions 504, and the instructions 504 can be executed on the processor, so that the communication apparatus 500 executes the methods described in the above method embodiments. Optionally, the memory 502 may also store data. The processor and the memory can be provided separately or integrated together.

Optionally, the communication apparatus 500 may include instructions 503 (sometimes also referred to as codes or programs), and the instructions 503 may be executed on the processor, so that the communication apparatus 500 executes the methods described in the above embodiments . Data may be stored in the processor 501 .

Optionally, the communication apparatus 500 may further include a transceiver 505 and an antenna 506 . The transceiver 505 may be referred to as a transceiver unit, a transceiver, a transceiver circuit, a transceiver, an input/output interface, etc., and is used to implement the transceiver function of the communication device 500 through the antenna 506 .

Optionally, the communication device 500 may further include one or more of the following components: a wireless communication module, an audio module, an external memory interface, an internal memory, a universal serial bus (universal serial bus, USB) interface, a power management module, an antenna, Speakers, microphones, I/O modules, sensor modules, motors, cameras, or displays, etc. It can be understood that, in some embodiments, the communication apparatus 500 may include more or less components, or some components may be integrated, or some components may be separated. These components may be implemented in hardware, software, or a combination of software and hardware.

The processor 501 and the transceiver 505 described in the embodiments of the present application may be implemented in an integrated circuit (IC), an analog IC, a radio frequency identification (RFID), a mixed-signal IC, and an application specific integrated circuit (application specific integrated circuit). integrated circuit, ASIC), printed circuit board (printed circuit board, PCB), or electronic equipment, etc. To implement the communication apparatus described herein, it may be an independent device (eg, an independent integrated circuit, a mobile phone, etc.), or may be a part of a larger device (eg, a module that can be embedded in other devices). The description of the terminal device and the network device will not be repeated here.

The embodiments of the present application provide a terminal device (for convenience of description, referred to as UE), which can be used in the foregoing embodiments. The terminal device includes corresponding means, units and/or circuits for implementing the functions of the terminal device described in any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 4 . For example, a terminal device includes a transceiver module, which is used to support the terminal device to implement a transceiver function, and a processing module, which is used to support the terminal device to process signals.

FIG. 6 is a schematic structural diagram of a terminal device provided by an embodiment of the present application.

The terminal device 600 is applicable to the architecture shown in FIG. 1 . For convenience of explanation, FIG. 6 only shows the main components of the terminal device 600 . As shown in FIG. 6 , the terminal device 600 includes a processor, a memory, a control circuit, an antenna, and an input and output device. The processor is mainly used to process communication protocols and communication data, and to control the entire terminal device 600 , execute software programs, and process data of the software programs. The memory is mainly used to store software programs and data. The control circuit is mainly used for the conversion of the baseband signal and the radio frequency signal and the processing of the radio frequency signal. Antennas are mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, microphones, keyboards, etc., are mainly used to receive data input by users and output data to users.

Taking the terminal device 600 as a mobile phone as an example, when the terminal device 600 is powered on, the processor can read the software program in the storage unit, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the control circuit. The control circuit performs radio frequency processing on the baseband signal and sends the radio frequency signal through the antenna in the form of electromagnetic waves. When data is sent to the terminal device 600, the control circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor, which converts the baseband signal into data and processes the data .

Those skilled in the art can understand that, for the convenience of description, FIG. 6 only shows one memory and one processor. In some embodiments, terminal device 600 may include multiple processors and memories. The memory may also be referred to as a storage medium or a storage device, etc., which is not limited in this embodiment of the present invention.

As an optional implementation manner, the processor may include a baseband processor and a central processing unit. The baseband processor is mainly used to process communication protocols and communication data, and the central processing unit is mainly used to control the entire terminal device 600. The software program is executed, and the data of the software program is processed. The processor in FIG. 6 integrates the functions of the baseband processor and the central processing unit. Those skilled in the art can understand that the baseband processor and the central processing unit may also be independent processors, interconnected by technologies such as a bus. The terminal device 600 may include multiple baseband processors to adapt to different network standards, the terminal device 600 may include multiple central processors to enhance its processing capability, and various components of the terminal device 600 may be connected through various buses. The baseband processor may also be expressed as a baseband processing circuit or a baseband processing chip. The central processing unit can also be expressed as a central processing circuit or a central processing chip. The function of processing the communication protocol and communication data may be built in the processor, or may be stored in the storage unit in the form of a software program, and the processor executes the software program to realize the baseband processing function.

In one example, the antenna and control circuit with a transceiving function can be regarded as the transceiving unit 610 of the terminal device 600 , and the processor having a processing function can be regarded as the processing unit 620 of the terminal device 600 . As shown in FIG. 6 , the terminal device 600 includes a transceiver unit 610 and a processing unit 620 . The transceiving unit may also be referred to as a transceiver, a transceiver, a transceiving device, or the like. Optionally, the device for implementing the receiving function in the transceiver unit 610 may be regarded as a receiving unit, and the device for implementing the transmitting function in the transceiver unit 610 may be regarded as a transmitting unit, that is, the transceiver unit 610 includes a receiving unit and a transmitting unit. Exemplarily, the receiving unit may also be referred to as a receiver, a receiver, a receiving circuit, and the like, and the transmitting unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, or the like.

The embodiment of the present application also provides a network device, and the network device can be used in each of the foregoing embodiments. The network device includes means, units and/or circuits for implementing the functions of the network device described in any one of the embodiments shown in FIG. 2 to 4 . For example, the network device includes a transceiver module to support the network device to implement a transceiver function, and a processing module to support the network device to process signals.

FIG. 7 is a schematic structural diagram of a network device provided by an embodiment of the present application. As shown in FIG. 7 , the network equipment can be applied to the architecture shown in 1. The network equipment includes: a baseband device 701 , a radio frequency device 702 , and an antenna 703 . In the uplink direction, the radio frequency device 702 receives the information sent by the terminal device through the antenna 703, and sends the information sent by the terminal device to the baseband device 701 for processing. In the downlink direction, the baseband device 701 processes the information of the terminal device and sends it to the radio frequency device 702 , and the radio frequency device 702 processes the information of the terminal device and sends it to the terminal device through the antenna 703 .

The baseband device 701 includes one or more processing units 7011 , storage units 7012 and interfaces 7013 . The processing unit 7011 is configured to support the network device to perform the functions of the network device in the foregoing method embodiments. The storage unit 7012 is used to store software programs and/or data. The interface 7013 is used for exchanging information with the radio frequency device 702, and the interface includes an interface circuit for inputting and outputting information. In one implementation, the processing unit is an integrated circuit, such as one or more ASICs, or, one or more DSPs, or, one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits can be integrated together to form chips. The storage unit 7012 and the processing unit 7011 may be located in the same chip, that is, an on-chip storage element. Alternatively, the storage unit 7012 may be located on a different chip from the processing unit 7011, that is, an off-chip storage element. The storage unit 7012 may be one memory, or may be a collective term for multiple memories or storage elements.

The network device may implement some or all of the steps in the foregoing method embodiments in the form of one or more processing unit schedulers. For example, the corresponding functions of the network device described in any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 4 are implemented. The one or more processing units may support wireless access technologies of the same standard, or may support wireless access standards of different standards.

Those of ordinary skill in the art can realize that the units and steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. The units described as separate components may or may not be physically separated. The components shown may or may not be physical units, ie may be located in one place, or may be distributed over multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

The functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned computer-readable storage medium can be any available medium that can be accessed by a computer. Taking this as an example but not limited to: the computer-readable medium may include random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), Erasable programmable read only memory (erasable PROM, EPROM), electrically erasable programmable read only memory (electrically erasable programmable read only memory, EEPROM), compact disc read-only memory (compact disc read-only memory, CD- ROM), universal serial bus flash disk, removable hard disk, or other optical disk storage, magnetic disk storage medium, or other magnetic storage device, or capable of carrying or storing desired data in the form of instructions or data structures program code and any other medium that can be accessed by a computer. Additionally, by way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (synchlink DRAM) , SLDRAM) or direct memory bus random access memory (direct rambus RAM, DR RAM).

The above are only specific implementations of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes within the technical scope disclosed in the embodiments of the present application. Or alternatives, all should be covered within the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be based on the protection scope of the claims.

Claims

A communication method, comprising:

In the process of selecting a network, the terminal device obtains first indication information, where the first indication information is used to indicate that the terminal device has experienced a radio link failure event in the network corresponding to the first indication information;

The terminal device selects a network according to the first indication information.
The method according to claim 1, wherein the method further comprises:

The NAS layer of the terminal device determines that the first network corresponds to the first indication information, and the first network is the network where the terminal device registered last time.
The method according to claim 1 or 2, wherein the terminal device selects a network according to the first indication information, comprising:

The NAS layer of the terminal device selects the second network from the networks to be selected according to the first threshold and the first indication information.
The method according to claim 3, wherein the NAS layer of the terminal device selects the second network from the networks to be selected according to the first threshold and the first indication information, comprising:

The NAS layer of the terminal device selects the second network from the networks to be selected; wherein,

The NAS layer of the terminal device determines, according to a first method, whether a network having the first indication information in the to-be-selected network is optional, and determines, according to a second method, that the network to be selected does not have the first indication information. Whether the network of the indication information is optional; or, the NAS layer of the terminal device determines whether all the networks in the to-be-selected network are optional according to a first method; the first method is related to the first threshold, The second manner is independent of the first threshold, and the first threshold is used by the terminal device to select a network in the presence of the first indication information.
The method according to claim 1, wherein the terminal device selects a network according to the first indication information, comprising:

The NAS layer of the terminal device selects a second network from the networks to be selected, where the networks to be selected include networks in which the first indication information does not exist.
The method according to any one of claims 1 to 5, wherein obtaining the first indication information by the terminal device comprises:

In the case that the measured value of the first cell corresponding to the third network is less than or equal to the second threshold, the AS layer of the terminal device determines whether the terminal device has experienced a radio link failure event in the third network, wherein , the terminal equipment satisfies the cell selection criteria of the first cell;

If the terminal device has experienced a radio link failure event in the third network, the AS layer of the terminal device sends the measurement value of the first cell corresponding to the third network to the NAS layer of the terminal device and the identifier of at least one network, and sending at least one of the first indication information corresponding to the at least one network, the at least one network includes all or part of the network corresponding to the first cell, and the at least one network The network includes the third network.
The method according to claim 6, wherein the method further comprises:

In the case that the measured value of the first cell corresponding to the third network is greater than the second threshold, the AS layer of the terminal device sends the identifier of the third network to the NAS layer of the terminal device, and indicates The third network is a high-quality network.
The method according to claim 1, wherein obtaining the first indication information by the terminal device comprises:

In the case that the measured value of the first cell corresponding to the third network is less than or equal to the second threshold, the AS layer of the terminal device determines whether the terminal device has experienced a radio link failure event in the third network, wherein , the terminal equipment satisfies the cell selection criteria of the first cell;

If the terminal device has a radio link failure event in the third network, the AS layer of the terminal device obtains the first indication information of the third network.
The method according to claim 8, wherein the terminal device selects a network according to the first indication information, comprising:

The AS layer of the terminal device does not send the identification of the third network to the NAS layer of the terminal device, wherein the identification of the third network is not sent for the NAS layer of the terminal device to not select a network when selecting a network. Select the third network.
The method according to any one of claims 1 to 9, wherein the method further comprises:

After the second network is selected, second indication information is sent to the network device, where the second indication information is used to indicate that the terminal device has experienced a radio link failure event in the second cell of the fourth network.
The method according to any one of claims 1 to 10, wherein the method further comprises:

After selecting the second network, send the identifier of the second network and the identifier of the third cell where the terminal device is located to the network device;

receiving information from M networks of the network device, where the M networks are networks in the area where the third cell is located, and M is a positive integer;

When a network is selected again, available networks are searched according to the information of the M networks.
The method according to any one of claims 1 to 11, wherein the first network is a PLMN or an NPN.
A terminal device, characterized in that it includes:

one or more processors;

one or more memories;

and one or more computer programs, wherein the one or more computer programs are stored in the one or more memories, the one or more computer programs including instructions, when the instructions are executed by the terminal device When executed by one or more processors, the terminal device is caused to execute the method according to any one of claims 1-12.
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 run on a computer, the computer is made to execute any one of claims 1 to 12. method described in item.
A chip, characterized by comprising one or more processors and a communication interface, wherein the one or more processors are used to read instructions to execute the method of any one of claims 1-12.