CN114302469B

CN114302469B - Cell searching method and device, equipment and storage medium

Info

Publication number: CN114302469B
Application number: CN202210043037.7A
Authority: CN
Inventors: 谢朝阳
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2022-01-14
Filing date: 2022-01-14
Publication date: 2024-02-13
Anticipated expiration: 2042-01-14
Also published as: CN114302469A

Abstract

The application provides a cell searching method and device, equipment and a storage medium; wherein the method comprises the following steps: determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; maintaining a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, wherein the first S-nsai is one of the at least one S-nsai; and performing cell search in a second network based on the current access mode.

Description

Cell searching method and device, equipment and storage medium

Technical Field

The present application relates to communications technologies, and in particular, but not exclusively, to a method and apparatus for cell search, a device, and a storage medium.

Background

Network slicing is a logical network and partition of the third generation partnership project (3rd Generation Partnership Project,3GPP) wireless network. A network slice is created to serve a particular purpose or group of clients. The single network slice selection assistance information (Single Network Slice Selection Assistance Information, S-nsai) may be used to identify the network slice. Thus, S-NSSAI may also be referred to as S-NNSAI identifier. After a User Equipment (UE) selects one network slice from a plurality of network slices allowed to access to register, the UE may use the network slice for data communication.

However, in the use process of the UE based on the above technology, there may be a case that the UE cannot be switched to the high-speed cell more quickly.

Disclosure of Invention

In view of this, the method, the device, the equipment and the storage medium for cell search provided by the present application advance the time of cell search by the UE in the second network, so that the UE can find a suitable cell access in the second network more quickly.

According to an aspect of the embodiments of the present application, there is provided a cell search method, including: determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; maintaining a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, wherein the first S-nsai is one of the at least one S-nsai; and performing cell search in a second network based on the current access mode.

In this manner, since it is determined whether the reject cause of one of the at least one S-nsai (i.e., the first S-nsai) is rejected by the first network or is rejected due to authentication or authentication failure, rather than determining whether the reject cause of each S-nsai is any of the above reasons, the number of operation steps is greatly reduced. That is, based on determining that the reject cause corresponding to the first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, cell search is directly performed on the second network, so that a verification process is shortened, the time of performing cell search on the second network by the UE is advanced, and the UE can find a suitable cell for access on the second network more quickly.

According to an aspect of the embodiments of the present application, there is provided another cell search method, including: determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; maintaining a current access mode based on determining that a reject cause corresponding to a second S-nsai is a first registration area rejecting the second S-nsai, wherein the second S-nsai is one of the at least one S-nsai; and performing cell search in a second registration area of the first network based on the current access mode.

In this way, on one hand, since it is not necessary to determine whether all S-nsais in the registration request message are rejected, but only whether the reason for rejecting one of the at least one S-nsais (i.e., the second S-nsai) is whether the first registration area rejects the second S-nsai, so that the operation steps are reduced, the time for the UE to search for the cell in the second registration area is advanced, and the UE can find a suitable cell in the second registration area to access more quickly; on the other hand, when the reject cause corresponding to the second S-nsai is that the first registration area rejects the second S-nsai, the cell search is not directly performed in the second network, but performed in the second registration area of the current network (i.e., the first network); therefore, the range of cell search is reduced, the cell search time is shortened, the cell search efficiency is improved, and the UE can access to the cell supporting the current access mode as soon as possible.

According to an aspect of an embodiment of the present application, there is provided a cell search apparatus including: a determining module, configured to determine, according to a registration rejection message returned by the first network for the registration request message, at least one S-nsai that is rejected and a reject reason corresponding to each S-nsai; wherein the registration request message carries the at least one S-nsai; a first search module, configured to maintain a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, and perform cell search at a second network based on the current access mode; wherein the first S-NSSAI is one of the at least one S-NSSAI.

According to an aspect of the embodiments of the present application, there is provided another cell search apparatus, including: a determining module, configured to determine, according to a registration rejection message returned by the first network for the registration request message, at least one S-nsai that is rejected and a reject reason corresponding to each S-nsai; wherein the registration request message carries the at least one S-nsai; a second search module, configured to maintain a current access mode based on determining that a reject cause corresponding to a second S-nsai is a reject of the second S-nsai by a first registration area, and perform cell search in a second registration area of the first network based on the current access mode; wherein the second S-NSSAI is one of the at least one S-NSSAI.

According to an aspect of the embodiments of the present application, there is provided a user equipment, including a memory and a processor, the memory storing a computer program executable on the processor, the processor implementing the method of the embodiments of the present application when executing the program.

According to an aspect of the embodiments of the present application, there is provided a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the method provided by the embodiments of the present application.

According to an aspect of embodiments of the present application, there is provided a user equipment comprising a communication module configured to: determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; maintaining a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, wherein the first S-nsai is one of the at least one S-nsai; and performing cell search in a second network based on the current access mode.

According to an aspect of embodiments of the present application, there is provided a user equipment comprising a communication module configured to: determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; maintaining a current access mode based on determining that a reject cause corresponding to a second S-nsai is a first registration area rejecting the second S-nsai, wherein the second S-nsai is one of the at least one S-nsai; and performing cell search in a second registration area of the first network based on the current access mode.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the technical aspects of the application. It is apparent that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

The flow diagrams depicted in the figures are exemplary only, and do not necessarily include all of the elements and operations/steps, nor must they be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the order of actual execution may be changed according to actual situations.

Fig. 1 is a schematic implementation flow chart of a cell search method provided in an embodiment of the present application;

fig. 2 is a schematic implementation flow chart of another cell search method according to an embodiment of the present application;

fig. 3 is a schematic implementation flow chart of another cell search method according to an embodiment of the present application;

FIG. 4 is a diagram illustrating a relationship between a registration area and a tracking area;

fig. 5 is a schematic implementation flow chart of another cell search method according to an embodiment of the present application;

fig. 6 is a schematic implementation flow chart of another cell search method according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of a cell search apparatus according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of another cell search apparatus according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of a user equipment according to an embodiment of the present application.

Detailed Description

For the purposes, technical solutions and advantages of the embodiments of the present application to be more apparent, the specific technical solutions of the present application will be described in further detail below with reference to the accompanying drawings in the embodiments of the present application. The following examples are illustrative of the present application, but are not intended to limit the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to be limiting of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with one another without conflict.

An embodiment of the present application provides a cell search method, and fig. 1 is a schematic flow chart of implementation of the cell search method provided in the embodiment of the present application, as shown in fig. 1, the method may include the following steps 101 to 102:

step 101, the UE determines at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai.

In this embodiment of the present application, the at least one S-nsai may be all S-nsais carried by the registration request message, or may be a part of S-nsais therein.

Step 102, the ue maintains a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or authentication of the first S-nsai fails, and performs cell search in a second network based on the current access mode; wherein the first S-NSSAI is one of the at least one S-NSSAI.

In some embodiments, maintaining the current access mode based on determining that the reject cause corresponding to the first S-nsai is that the first network rejects the first S-nsai or that authentication or authentication of the first S-nsai fails, further comprising: and traversing the at least one S-NSSAI until determining that the reject reason corresponding to each S-NSSAI is that the first network rejects the S-NSSAI or authentication failure of the S-NSSAI.

In the embodiment of the present application, since it is determined whether the reject cause of one of the at least one S-nsai (i.e., the first S-nsai) is rejected by the first network or is rejected due to authentication or authentication failure, rather than determining whether the reject cause of each S-nsai is any of the above reasons, the operation steps are greatly reduced. That is, based on determining that the reject cause corresponding to the first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, cell search is directly performed on the second network, so that a verification process is shortened, the time of performing cell search on the second network by the UE is advanced, and the UE can find a suitable cell for access on the second network more quickly.

In some embodiments, the method further comprises: the UE maintains a current access mode based on the fact that all S-NSSAI carried by the registration request message are refused and the reason for refusing corresponding to each S-NSSAI carried by the registration request message is that the first network refuses the S-NSSAI or authentication of the S-NSSAI fails; and performing cell search in a second network based on the current access mode.

In some embodiments, the reason value carried by the registration reject message is a value indicating that no network slices are available (# 62).

In some embodiments, the reject NSSAI field carried in the registration reject message indicates which S-NSSAI or S-NSSAIs are rejected by the first network for which reason. The reject reasons include: rejected by the first network (i.e., rejected by the current network), rejected by the current registration area, and rejected due to authentication or authentication failure.

In some embodiments, the UE sends a registration request message to the first network, where the message includes slice information requested by the UE. The first network side replies to the registration rejection and the reason for the rejection is no available network slices (# 62). The registration reject message may indicate that the UE has partially or fully rejected its requested slice and may flag the reason for each slice being rejected. According to protocol 3GPP TS24.501, the slice requested by the UE is rejected for 4 reasons, and authentication or authentication failure is one of the 4 reasons.

It should be noted that the current access mode may be an N1 mode or another RAT mode, and in any case, when the above condition is satisfied, the UE does not disable the current access mode, but performs cell search on a second network different from the first network based on the current access mode.

In some embodiments, based on determining that the S-nsais carried by the registration request message are all rejected, and each of the S-nsais rejected because the first network rejects the S-nsais or authentication of the S-nsais fails, the UE disables the current access mode and attempts to search for network residences under other RATs supported by the current network, with the end result that the UE falls back onto a lower RAT network. For example, the current access mode of the UE is N1 mode, and eventually falls back onto a 4G or even 3G cell, thereby making it impossible for the user to enjoy the NR high-speed network.

In view of this, in some embodiments, based on determining that the S-nsai carried by the registration request message includes all rejected and that each S-nsai corresponds to a rejection cause of the first network rejecting S-nsai or authentication failure of S-nsai, the UE does not disable the current access mode but performs a cell search at a second network different from the first network based on the current access mode; in this way, the chance of the UE to continue camping on the cell supporting the current access mode (e.g. N1 mode) is increased.

It should be noted that, in the embodiment of the present application, the types of the first network and the second network are not limited, and may be public land mobile networks (Public Land Mobile Network, PLMN) or other types of networks. The second network comprises a network supporting the current access mode.

The embodiment of the application further provides a cell searching method, which comprises the following steps: the UE determines at least one S-NSSAI which is refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; the UE is based on determining that the reject cause corresponding to the second S-NSSAI is that the first registration area rejects the second S-NSSAI, maintaining a current access mode, and carrying out cell search in the second registration area of the first network based on the current access mode; wherein the second S-NSSAI is one of the at least one S-NSSAI.

In the embodiment of the application, on one hand, whether the S-NSSAI in the registration request message is completely refused is not required to be determined, but only whether the refusing reason of one of the at least one S-NSSAI (namely, the second S-NSSAI) is whether the first registration area refuses the second S-NSSAI is determined, so that the operation steps are reduced, the time for the UE to search for the cell in the second registration area is shortened, and the UE can find a suitable cell in the second registration area to access more quickly; on the other hand, when the reject cause corresponding to the second S-nsai is that the first registration area rejects the second S-nsai, the cell search is not directly performed in the second network, but performed in the second registration area of the current network (i.e., the first network); therefore, the range of cell search is reduced, the cell search time is shortened, the cell search efficiency is improved, and the UE can access to the cell supporting the current access mode as soon as possible.

An embodiment of the present application further provides a cell search method, and fig. 2 is a schematic flowchart of an implementation flow of another cell search method provided in an embodiment of the present application, as shown in fig. 2, where the method includes steps 201 to 215 below:

step 201, a non-access stratum of a ue sends a registration request message to a first network, where the registration request message carries a requested nsai, and the nsai includes one or more S-nsais;

step 202, a non-access layer of the UE receives a registration rejection message returned by the first network based on the registration request message; and the reason value carried by the registration refusal message is an unavailable network slice.

Step 203, the non-access layer of the ue determines, according to the registration rejection message, a rejected S-nsai and a corresponding reject reason, and determines whether all S-nsais included in the requested nsai are rejected based on this; if so, go to step 205; otherwise, go to step 204;

step 204, the access layer of the ue continues to reside in the current serving cell and re-initiates the registration procedure;

step 205, the non-access stratum of the ue determines whether the reject reason corresponding to each S-nsai is the rejection of the S-nsai or the authentication or authentication failure of the S-nsai by the first network; if so, go to step 206; otherwise, step 215 is performed.

Of course, the judging sequence of step 203 and step 204 is not limited, and step 206 is executed in any case based on determining that all S-nsais included in the requested nsai are rejected, and that each of the S-nsais is rejected because the authentication or authentication of the first network rejecting the S-nsai or the S-nsai fails; otherwise, if all of the S-nsais included in the requested nsais are rejected and at least one of the S-nsais is rejected for the first registration area, step 215 is performed.

Step 206, deleting the identifier of the first network from the stored first network list by the non-access layer of the ue to obtain a second network list; the first network list comprises the identification of the first network and the identification of the equivalent network with the same priority as the first network.

The equivalent network, also called peer-to-peer network, is a network that is equally located with the first network and has the same priority, i.e. the priority of the selection to camp on. For example, the first network is a PLMN, its equivalent network is an EPLMN, and the first network list is an EPLMN list.

In step 207, the non-access layer of the ue sends the second network list to the access layer to instruct the access layer to maintain a current access mode, and based on the current access mode, performs cell search on the equivalent network indicated by the second network list.

It can be understood that the UE has prestored therein the identity of the equivalent network with the same priority as the first network, i.e. the first network list, so when all the S-nsais included in the requested nsai are rejected and the reject factor corresponding to each S-nsai is that the first network rejects the authentication or authorization of the S-nsai, the cell search is directly performed based on the second network list without scanning the currently available network first and then performing the cell search on the available network obtained by the search; thus, the overall network searching time is shortened, and the UE can be accessed to the cell supporting the current access mode as soon as possible.

Step 208, the non-access stratum of the ue determines whether to successfully camp on and register with a suitable (subscribed) cell; if yes, ending; otherwise, go to step 209;

that is, step 209 is performed based on a determination that no suitable cell is searched for in the equivalent network in the current access mode. Of course, nor is it limited to performing step 209, in some embodiments, based on determining that no suitable cell is searched for in the equivalent network in the current access mode, the non-access stratum of the UE may also instruct the access stratum to disable the current access mode, and based on another access mode different from the current access mode, conduct a cell search at the first network; thus, the probability of the UE accessing to the cell supporting the current access mode is improved, and the UE can recover network service as soon as possible.

For example, the current access mode is an N1 mode, and the other access mode different from the current access mode is an S1 mode.

Or in other embodiments, based on determining that no suitable cell is searched in the equivalent network according to the current access mode, the non-access layer of the UE may also send the recorded disabling information and the third network list to the access layer, and instruct the access layer to maintain the current access mode, so as to perform a cell search in the network indicated by the third network list based on the current access mode and the disabling information; wherein the forbidden information comprises the identification of a cell which does not support the current access mode and the identification of a network to which the forbidden information belongs; the third network list includes an identification of at least one of the following networks: home network, peer-to-peer home network, user control network, operator control network, network meeting high quality conditions, network not meeting high quality conditions.

Further, illustratively, the home network is a local public land mobile network (Home Public Land Mobile Network, HPLMN); the peer-to-peer home network is EHPLMN (Equivalent Home PLMN); the user control network is UPLMN (User Controlled PLMN); the operator control network is OPLMN (Operator Controlled PLMN). That is, the UE may search for suitable cells in sequence according to PLMN priority specified in the 3GPP protocol TS 23.122.

It will be appreciated that, based on determining that no suitable cell is searched in the equivalent network in the current access mode, instead of disabling the current access mode, the recorded disabling information and the third network list are sent to the access layer, based on which a cell of a lower RAT is searched; in this way, the UE does not need to repeatedly turn on and off the current access mode.

The suitable cell refers to a cell in which cell measurement information such as corresponding signal reception quality satisfies a condition. For example, the cell selected according to the S criteria is the appropriate cell.

In step 209, the non-access stratum of the ue instructs the access stratum to search for currently available networks.

By available network, it is meant in some embodiments the network to which the cell to which the received signal quality and/or received signal strength etc. parameter is greater than or equal to a threshold value belongs.

Step 210, the non-access layer of the ue selects a target available network satisfying the condition from the currently available networks; wherein the condition includes supporting the current access mode.

In some embodiments, the condition further comprises a priority higher than or equal to a priority of the first network. That is, the target available network needs to satisfy these two points simultaneously: (1) supporting the current access mode; (2) With a priority higher than or equal to the priority of the first network.

In step 211, the non-access stratum of the ue sends the identity of the target available network to the access stratum.

In some embodiments, the non-access stratum of the UE may obtain the identity of the currently available network, select a target available network from among the currently available networks that satisfies the condition, and add its identity to the list; based on determining that the list is not empty, transmitting the list to the access layer so that the access layer performs cell search according to the target available network indicated in the list; based on determining that the list is empty, indicating that a target available network satisfying the condition does not exist in the current surrounding environment, wherein the non-access layer can instruct the access layer to disable the current access mode, and based on another access mode different from the current access mode, performing cell search on the first network; or, in some embodiments, based on determining that there is no target available network satisfying the condition in the currently available networks, transmitting recorded disabling information and a third network list to the access layer to instruct the access layer to maintain the current access mode, and performing a cell search at a network indicated by the third network list based on the current access mode and the disabling information;

Wherein the forbidden information comprises the identification of a cell which does not support the current access mode and the identification of a network to which the forbidden information belongs; the third network list includes an identification of at least one of the following networks: home network, peer-to-peer home network, user control network, operator control network, network meeting high quality conditions, network not meeting high quality conditions.

In step 212, the non-access layer of the ue instructs the access layer to perform cell search on the network indicated by the identifier of the target available network based on the current access mode.

It will be appreciated that, based on a determination that no suitable cell has been searched for in the equivalent network in the current access mode, instead of disabling the current access mode, surrounding available networks are further scanned for cell searches based on the current access mode on these networks; in this way, the chance of the UE camping on the cell supporting the current access mode can be further increased.

In some embodiments, the identification of the target available network includes an identification of at least one of the following networks, and the access layer of the UE may perform cell search sequentially from higher priority to lower priority:

(1) EPLMN of current PLMN (not including current PLMN); wherein the current PLMN is an example of the first network;

(2) HPLMN (if the current PLMN is not HPLMN/EHPLMN);

(3) UPLMN (if the current PLMN belongs to either UPLMN, OPLMN or high signal quality PLMN);

(4) OPLMN (if the current PLMN belongs to OPLMN or high signal quality PLMN);

(5) High signal quality PLMNs (if the current PLMN belongs to a high signal quality PLMN).

Step 213, the non-access stratum of the ue determines whether to successfully camp on and register to a suitable cell; if yes, ending; otherwise, step 214 is performed.

That is, step 214 is performed based on a determination that no suitable cells have been searched for in the target available network in the current access mode. Of course, also not limited to performing step 214, in some embodiments, based on determining that no suitable cell is searched for in the target available network in the current access mode, or based on determining that no target available network satisfying the condition exists in the current available networks, sending recorded disabling information and a third network list to the access layer to instruct the access layer to maintain the current access mode, to perform a cell search in the network indicated by the third network list based on the current access mode and the disabling information;

In step 214, the non-access stratum of the ue instructs the access stratum to disable the current access mode and to conduct a cell search at the first network based on another access mode than the current access mode.

In some embodiments, the other access mode than the current access mode has a lower priority than the current access mode, e.g., the other access mode than the current access mode is an S1 mode and the current access mode is an N1 mode.

In step 215, the non-access stratum of the ue instructs the access stratum to maintain a current access mode and, based on the current access mode, conduct a cell search in a second registration area of the first network.

As can be appreciated, the reject causes include: rejected by the first network (i.e., rejected by the current network), rejected by the current registration area, and rejected due to authentication or authentication failure. Based on determining that all S-nsais included in the requested nsais are rejected, and that the reject reasons are not all rejected by the first network and are rejected due to authentication or authentication failure, then at least one of the S-nsais is rejected by a first registration area (where the first registration area may be understood as a current registration area), at which time a current access layer is maintained, and based on the current access mode, cell search is not performed first in other networks but in a second registration area of a current network (i.e., the first network); therefore, the range of cell search is reduced, the cell search time is shortened, the cell search efficiency is improved, and the UE can be accessed to the cell supporting the current access mode as soon as possible.

An embodiment of the present application further provides a cell search method, and fig. 3 is a schematic implementation flow chart of another cell search method provided in the embodiment of the present application, as shown in fig. 3, where the method includes the following steps 301 to 306:

step 301, determining a rejected S-nsai and a corresponding reject reason by a non-access stratum of the ue according to a registration reject message returned by the first network for the registration request message; the registration request message carries a requested NSSAI, and the reason value carried by the registration rejection message is a value indicating that no network slice is available;

in step 302, the non-access stratum of the ue indicates to the access stratum to maintain the current access mode based on determining that all S-nsais included in the requested nsais are rejected, and that at least one of the S-nsais is rejected as being rejected by the first registration area.

It should be noted that, the rejection by the first registration area is the rejection by the current registration area, and is referred to herein as the first registration area, in order to be distinguished from the second registration area mentioned below. The second registration area is an area that does not entirely overlap with the first registration area.

Step 303, the non-access layer of the ue sends the received tracking area list as a forbidden tracking area list to the access layer, so as to instruct the access layer to perform cell search in a tracking area of the first network except for the tracking area indicated by the forbidden tracking area list based on the current access mode and the forbidden tracking area list; wherein the forbidden tracking area list comprises identification of forbidden tracking areas;

For example, as shown in fig. 4, the first network includes a first registration area 401 and a second registration area 402; the non-access stratum layer transmits tracking area identifications (Tracking Area Identity, TAI) contained in a tracking area list (TAI list) received on the current registration area 401 as forbidden TAIs to the access stratum layer, as shown in fig. 4, wherein the tracking area list includes TAI1 and TAI2, that is, identifications of a tracking area 4011 and a tracking area 4012; and PLMN (selected PLMN), the non-access stratum having the current PLMN (i.e., one example of the first network) as a choice, instructing the access stratum to perform a cell search; then, if the access layer can find a suitable NR cell in the tracking area 4021 indicated by TAI3, it will directly access the cell, thereby entering the NR service state.

Step 304, the non-access stratum of the ue determines whether to successfully camp on and register to a suitable cell; if yes, ending; otherwise, step 305 is performed.

That is, if no suitable cell is searched for in the tracking areas of the first network other than the access-prohibited tracking area, step 305 is performed.

Step 305, the non-access layer of the ue sends a third network list to the access layer; and

step 306, the non-access layer of the ue instructs the access layer to perform cell search on the network indicated by the third network list based on the current access mode; wherein the third network list includes an identification of at least one of the following networks: home network, peer-to-peer home network, user control network, operator control network, network meeting high quality conditions, network not meeting high quality conditions.

In some embodiments, the access layer of the UE may perform cell search sequentially in order of higher priority of the networks in the third network list.

In some embodiments, as shown in fig. 5, when the UE sends a registration request, receives a registration reject message and the cause value is no network slice available (# 62), the reject NSSAI (rejected NSSAI) field carried in the registration reject message indicates which S-nsais are rejected by the network for what reason. The reject causes are three, namely "rejected by the current PLMN", "rejected by the current registration area" and "rejected due to authentication or authentication failure", respectively.

Depending on whether the UE has allowed NSSAI (allowed NSSAI), configured NSSAI (configured NSSAI) and default configured NSSAI (default configured NSSAI), the following two cases are classified:

(1) When the UE has an allowed NSSAI or configured NSSAI, if the S-NSSAI contained in the NSSAI is not totally rejected, the UE can continue to reside in the current service cell and then initiate a registration flow; if all S-NSSAIs are rejected, then the PLMN selection procedure needs to be triggered and the reason for rejection in the reject NSSAI field needs to be checked. If the reject cause is "rejected by the current PLMN" or "rejected due to authentication or authentication failure", the N1 mode of the current PLMN may be disabled and network searching camping may be attempted under other RATs supported by the current PLMN. If the reject cause comprises "rejected by the current registration area", the N1 mode of the current PLMN need not be disabled.

(2) When the UE has neither allowed nsai nor configured nsai, default configured NSSAI, if the contained S-nsai is not all rejected, the UE may continue camping on the current serving cell and subsequently restart the registration procedure. If all S-NSSAIs are rejected, then the PLMN selection procedure needs to be triggered and the reason for rejection in the reject NSSAI field needs to be checked. The N1 mode of the current PLMN may be disabled if the reject cause is "rejected by the current PLMN" or "rejected due to authentication or authentication failure". If the reject cause comprises "rejected by the current registration area", the N1 mode of the current PLMN need not be disabled.

According to the reject reason indicated in the reject NSSAI field of the reject registration message, the N1 mode divided into the current PLMN is disabled and not disabled when PLMN selection is performed. For both cases, there are two disadvantages that can affect the user experience:

the method has the following defects: when the reject reasons are both "rejected by the current PLMN" or "rejected due to authentication or authentication failure", the N1 mode of the current PLMN is disabled, resulting in the user UE dropping onto LTE or other RATs and being unable to enjoy the NR high-speed network. When the user uses the service with high throughput requirement, obvious network jamming occurs, and the user experience is affected. At this time, the equivalent PLMN currently registered with the rejected PLMN may provide NR normal service, and there may be other available PLMNs capable of providing NR normal service without attempting, thereby wasting the opportunity for the user UE to continue to camp on the NR network or to quickly resume NR normal service.

And the second disadvantage is that: when the reject cause includes "reject by current registration area", the N1 mode of the current PLMN need not be disabled. The current PLMN is excluded when the PLMN is selected, and then the search for the proper NR cell on the HPLMN/EHPLMN, UPLMN, OPLMN, the high signal quality PLMN and other PLMNs is sequentially attempted according to the priority according to the specified PLMN list. During the network searching period, the UE cannot provide normal service, and the experience of the user is affected. At this time, the UE is only rejected in the current registration area, and there may be other registration areas that can provide NR normal service; the UE directly starts the network searching process without trying other registration areas, so that the searching range is enlarged, the searching time is prolonged, precious time of a user is wasted, the service-free time of the user is prolonged, and the user experience is influenced.

However, both of these drawbacks are avoided or ameliorated.

Based on this, an exemplary application of the embodiments of the present application in one practical application scenario will be described below.

In view of the above technical drawbacks, in the embodiments of the present application, it is intended to provide a mechanism that when a UE requests registration, is rejected by the network due to no available network slice (cause # 62), and triggers PLMN selection, the UE can quickly resume NR normal service.

As shown in fig. 6, when the UE sends a registration request and receives a registration rejection message of the network, and configured nsai, allowed nsai or default configured NSSAI of the UE include all S-nsai (S) rejected by the network, and thus PLMN selection is triggered, the optimization scheme is subdivided into two cases according to the S-nsai reject reason indicated by the reject field in the reject message.

Scheme scenario 1: when the reject reason is 'rejected by the current PLMN' or 'rejected due to authentication or authentication failure', the access layer is not instructed to disable the N1 mode of the current PLMN and trigger network searching of other RATs, but the PLMN which receives registration reject is deleted from the EPLMN, the EPLMN is sent to the access layer to try network searching, and if a proper NR cell is found, the access layer directly enters an NR normal service state. If a proper NR cell cannot be found on the EPLMN, searching all PLMNs currently available through PLMN search, and checking whether PLMNs with priority higher than or equal to the current PLMNs and supporting NR RATs exist. If so, the NR cell search is preferentially attempted on the PLMN, and if not, PLMN selection is sequentially performed by priority according to a PLMN list specified in TS 23.122.

This has the advantage that the UE is given the opportunity to attempt to search for the appropriate NR cell on the EPLMN and other available PLMNs, and once the appropriate NR cell is found, normal NR service can be resumed.

Scheme scenario 2: when the reject cause includes "reject by current registration area", the N1 mode of the current PLMN need not be disabled, and the present optimization mechanism procedure is described by taking the registration area and TAI relationship shown in fig. 4 as an example. The non-access stratum issues the TAI list (containing TAI1 and TAI 2) received on the current registration area 401 to the access stratum as prohibited TAI (forbidden TAI). And the current PLMN is taken as a selected PLMN (selected PLMN), the access layer is instructed to execute cell search, and if the UE can find a proper NR cell in other registration areas of the current PLMN, namely TAI3 of the registration area 402, the UE directly enters an NR normal service state.

If the suitable NR cells cannot be searched in other registration areas of the current PLMN, the PLMN selection process is sequentially executed according to the priority according to the PLMN list specified in the TS 23.122.

The benefit of this is that the other registration areas of the current PLMN are directly tried first, rather than performing the PLMN selection procedure in order of priority according to the specified PLMN list, and if a suitable NR cell is found in the other registration areas of the current PLMN, the NR normal service can be restored more quickly. This is because, compared with sequentially performing PLMN searches according to a predetermined PLMN list, cell searches are performed in other registration areas of the current PLMN, the search range is greatly reduced, and the search time is also correspondingly shortened; the suitable NR cell refers to a cell that can reside and register successfully and provide normal service. The priority being higher than or equal to "in the current PLMN refers herein to a PLMN having the same PLMN class as the current PLMN, ignoring the priority ranking inside the same class PLMN. For example, when the current PLMN is an OPLMN, the current PLMN is considered to be the same as the priority of other PLMNs in the OPLMN.

The method comprises the following specific steps:

(1) It is queried whether the UE currently has stored allowed nsais, configured nsais and default configured NSSAI and their contained S-nsais. After receiving the registration reject message with the reason #62 sent by the network, it is possible to know which S-nsais of the UE are rejected by the network and the reason for the rejection from the rejected nsai field. Based on this information, it can be determined whether the UE can continue camping on the current serving cell or whether PLMN selection needs to be triggered. If PLMN selection needs to be triggered, a decision is made whether to employ scenario 1 or scenario 2 based on the reject cause indicated in the reject NSSAI field.

(2) When the PLMN selection needs to be triggered, the following two cases are classified according to whether scheme scenario 1 or scheme scenario 2 should be adopted currently:

if scheme scenario 1 is adopted, the specific steps are as follows:

step1: deleting the current PLMN from the EPLMN, and issuing the EPLMN as the selected PLMN to an access layer to start searching for a proper NR cell.

Step2: if the access layer finds a proper NR cell, the access layer directly enters an NR normal service state, and the flow ends.

Step3: and if the access layer cannot find a proper NR cell on the EPLMN, indicating the access layer to perform PLMN search.

Step4: it is checked whether all available PLMNs reported by the access stratum have priority. And PLMN(s) which are not lower than the current PLMN and support NR RAT and constitute a candidate PLMN list. This candidate PLMN list consists of several types of PLMNs, with priority order from high to low as follows:

1) EPLMN of current PLMN (not including current PLMN);

2) HPLMN (if the current PLMN is not HPLMN/EHPLMN);

3) UPLMN (if the current PLMN belongs to either UPLMN, OPLMN or high signal quality PLMN);

4) OPLMN (if the current PLMN belongs to OPLMN or high signal quality PLMN);

5) A high signal quality PLMN (if the current PLMN belongs to a high signal quality PLMN);

step5: if the PLMN list is not empty, sequentially trying NR RATs of the PLMN according to priority levels until NR cells which are suitable for residence and can be successfully registered are found; otherwise, returning to the current PLMN, an attempt is made to search for cells of other RATs.

If scenario 2 is employed, an attempt may be made again in other registration areas of the current PLMN. The method comprises the following specific steps:

step1: the non-access stratum layer sends the TAI list received in the current registration area to the access stratum layer as a forbidden TAI list.

Step2: the current PLMN is taken as the selected PLMN and the access layer is instructed to attempt cell search.

Step3: if the access layer finds a suitable residence cell and the registration is successful, the UE enters an NR normal service state, and the flow ends.

Step4: if the access layer finds a suitable residence cell and the registration is successful, the UE enters an NR normal service state, and the flow ends.

Step5: if the access layer does not find a suitable cell to camp on and register successfully, then the search is attempted sequentially according to the PLMN list specified in TS 23.122.

In the embodiment of the application, aiming at the situation that when the UE sends a registration request, no available network slice is refused to be registered by a network to trigger PLMN selection, according to the refused reason type in the refused NSSAI field of the registration refused message issued by the network, the cooperation of a non-access layer and an access layer is utilized to set an accurate network searching range, on the basis of not influencing the network searching efficiency specified in T23.122, the opportunity of users to enjoy NR normal service is increased, the network searching time of the users is shortened, and the user experience is improved.

It should be noted that although the steps of the methods in the present application are depicted in the accompanying drawings in a particular order, this does not require or imply that the steps must be performed in that particular order, or that all illustrated steps be performed, to achieve desirable results. Additionally or alternatively, certain steps may be omitted, multiple steps combined into one step to be performed, and/or one step decomposed into multiple steps to be performed, etc.; or, the steps in different embodiments are combined into a new technical scheme.

Based on the foregoing embodiments, the embodiments of the present application provide a cell search apparatus, where the apparatus includes each module included, and each unit included in each module may be implemented by a processor; or by specific logic circuits; in an implementation, the processor may be a Central Processing Unit (CPU), a Microprocessor (MPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or the like.

Fig. 7 is a schematic structural diagram of a cell search apparatus according to an embodiment of the present application, as shown in fig. 7, the apparatus 700 includes:

a determining module 701, configured to determine, according to a registration rejection message returned by the first network for the registration request message, at least one S-nsai that is rejected and a reject cause corresponding to each S-nsai; wherein the registration request message carries the at least one S-nsai;

a first search module 702, configured to maintain a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, and perform a cell search at a second network based on the current access mode; wherein the first S-NSSAI is one of the at least one S-NSSAI.

In some embodiments, the first search module 702 is further configured to: and traversing the at least one S-NSSAI until determining that the reject reason corresponding to each S-NSSAI is that the first network rejects the S-NSSAI or authentication failure of the S-NSSAI.

In some embodiments, the second network comprises an equivalent network of the same priority as the first network; a first search module 702, configured to: deleting the identification of the first network from the stored first network list to obtain a second network list; the first network list comprises the identification of the first network and the identification of the equivalent network with the same priority as the first network; and sending the second network list to the access layer to instruct the access layer to search cells in the equivalent network indicated by the second network list based on the current access mode.

In some embodiments, the first search module 702 is further configured to: the method further includes instructing the access layer to disable the current access mode based on determining that no suitable cell is searched for in the equivalent network in the current access mode, and performing a cell search at the first network based on another access mode different from the current access mode.

In some embodiments, the first search module 702 is further configured to: based on determining that no suitable cell is searched in the equivalent network according to the current access mode, transmitting recorded forbidden information and a third network list to the access layer, and instructing the access layer to maintain the current access mode so as to perform cell search in a network indicated by the third network list based on the current access mode and the forbidden information; wherein the forbidden information comprises the identification of a cell which does not support the current access mode and the identification of a network to which the forbidden information belongs; the third network list includes an identification of at least one of the following networks: home network, peer-to-peer home network, user control network, operator control network, network meeting high quality conditions, network not meeting high quality conditions.

In some embodiments, the first search module 702 is further configured to: based on determining that no suitable cell is searched in the equivalent network according to the current access mode, indicating the access layer to search for a current available network; selecting a target available network meeting the condition from the current available networks; wherein the condition includes supporting the current access mode; and sending the identification of the target available network to an access layer to instruct the access layer to search cells on the network indicated by the identification of the target available network based on the current access mode.

In some embodiments, the conditions further comprise: the priority is higher than or equal to the priority of the first network.

In some embodiments, the first search module 702 is further configured to: the method further includes instructing the access layer to disable the current access mode based on a determination that there is no target available network in the currently available networks that satisfies the condition, and performing a cell search at the first network based on another access mode different from the current access mode.

In some embodiments, the first search module 702 is further configured to: transmitting recorded forbidden information and a third network list to the access layer based on the fact that no target available network meeting the conditions exists in the current available networks, and instructing the access layer to maintain the current access mode so as to conduct cell search on the networks indicated by the third network list based on the current access mode and the forbidden information; wherein the forbidden information comprises the identification of a cell which does not support the current access mode and the identification of a network to which the forbidden information belongs; the third network list includes an identification of at least one of the following networks: home network, peer-to-peer home network, user control network, operator control network, network meeting high quality conditions, network not meeting high quality conditions.

In some embodiments, the second network comprises at least one of: the equivalent network with the same priority as the first network, a target available network in the currently available networks, which meets the conditions including supporting the current access mode.

In some embodiments, the current access mode is an N1 mode.

Fig. 8 is a schematic structural diagram of another cell search apparatus provided in the embodiment of the present application, and as shown in fig. 8, a cell search apparatus 800 includes:

a second search module 801, configured to maintain a current access mode based on determining that a reject cause corresponding to a second S-nsai is a reject of the second S-nsai by a first registration area, and perform cell search in a second registration area of the first network based on the current access mode; wherein the second S-NSSAI is one of the at least one S-NSSAI.

In some embodiments, the second searching module 801 is further configured to maintain the current access mode based on determining that each S-nsai carried by the registration request message is all rejected and that at least one reject cause corresponding to the S-nsai is a first registration area reject; and performing cell search in a second registration area of the first network based on the current access mode.

In some embodiments, the second search module 801 is configured to: transmitting the received tracking area list to the access layer as a forbidden tracking area list to instruct the access layer to search cells in tracking areas of the first network except for the tracking areas indicated by the forbidden tracking area list based on the current access mode; wherein the forbidden tracking area list includes an identification of forbidden tracking areas for access.

In some embodiments, the second search module 801 is further configured to: transmitting a third network list to the access layer to instruct the access layer to perform cell search on the network indicated by the third network list based on the current access mode based on the determination that no suitable cell is searched for in the tracking areas of the first network other than the tracking area indicated by the forbidden tracking area list; wherein the third network list includes an identification of at least one of the following networks: home network, peer-to-peer home network, user control network, operator control network, network meeting high quality conditions, network not meeting high quality conditions.

The description of the above device embodiments is similar to that of the method embodiments described above, with similar advantageous effects as the method embodiments. Technical details not disclosed in the device embodiments of the present application are understood from the description of the method embodiments of the present application.

It should be noted that, the division of the modules by the cell search apparatus in the embodiments of the present application is merely a logic function division, and other division manners may be implemented in practice. In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units. Or in a combination of software and hardware.

It should be noted that, in the embodiment of the present application, if the method is implemented in the form of a software functional module, and sold or used as a separate product, the method may also be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or portions contributing to the related art may be embodied in the form of a software product stored in a storage medium, including several instructions for causing a user equipment to perform all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read Only Memory (ROM), a magnetic disk, an optical disk, or other various media capable of storing program codes. Thus, embodiments of the present application are not limited to any specific combination of hardware and software.

An embodiment of the present application provides a user equipment, fig. 9 is a schematic diagram of a hardware entity of the user equipment in the embodiment of the present application, as shown in fig. 9, the user equipment 900 includes a memory 901 and a processor 902, where the memory 901 stores a computer program that can be run on the processor 902, and the processor 902 implements steps in the method provided in the embodiment described above when executing the program.

It should be noted that the memory 901 is configured to store instructions and applications executable by the processor 902, and may also be cached in the processor 902 and data (e.g., image data, audio data, voice communication data, and video communication data) to be processed or already processed by each module in the user equipment 900, and may be implemented by a FLASH memory (FLASH) or a random access memory (Random Access Memory, RAM).

The user device 900 may be various types of devices having wireless communication capabilities, for example, the user device 900 is a variety of types of handheld devices (e.g., a cell phone or tablet computer, etc.), mobile stations, vehicle-mounted devices, wearable devices, computing devices, internet of things devices, or other processing devices connected to a wireless modem, etc.

The embodiment of the application further provides a user equipment, which comprises a communication module, wherein the communication module is configured to: determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; maintaining a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, wherein the first S-nsai is one of the at least one S-nsai; and performing cell search in a second network based on the current access mode.

The embodiment of the application further provides a user equipment, which comprises a communication module, wherein the communication module is configured to: determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai; maintaining a current access mode based on determining that a reject cause corresponding to a second S-nsai is a first registration area rejecting the second S-nsai, wherein the second S-nsai is one of the at least one S-nsai; and performing cell search in a second registration area of the first network based on the current access mode.

The present embodiment provides a computer-readable storage medium, on which a computer program is stored, which when executed by a processor, implements the steps of the method provided in the above embodiment.

The present application provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the steps of the method provided by the method embodiments described above.

It should be noted here that: the description of the storage medium and apparatus embodiments above is similar to that of the method embodiments described above, with similar benefits as the method embodiments. For technical details not disclosed in the storage medium, storage medium and device embodiments of the present application, please refer to the description of the method embodiments of the present application for understanding.

It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" or "some embodiments" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application. The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments. The foregoing description of various embodiments is intended to highlight differences between the various embodiments, which may be the same or similar to each other by reference, and is not repeated herein for the sake of brevity.

The term "and/or" is herein merely an association relation describing associated objects, meaning that there may be three relations, e.g. object a and/or object B, may represent: there are three cases where object a alone exists, object a and object B together, and object B alone exists.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described embodiments are merely illustrative, and the division of the modules is merely a logical function division, and other divisions may be implemented in practice, such as: multiple modules or components may be combined, or may be integrated into another system, or some features may be omitted, or not performed. In addition, the various components shown or discussed may be coupled or directly coupled or communicatively coupled to each other via some interface, whether indirectly coupled or communicatively coupled to devices or modules, whether electrically, mechanically, or otherwise.

The modules described above as separate components may or may not be physically separate, and components shown as modules may or may not be physical modules; can be located in one place or distributed to a plurality of network units; some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional module in each embodiment of the present application may be integrated in one processing unit, or each module may be separately used as one unit, or two or more modules may be integrated in one unit; the integrated modules may be implemented in hardware or in hardware plus software functional units.

Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the above method embodiments may be implemented by hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, where the program, when executed, performs steps including the above method embodiments; and the aforementioned storage medium includes: a mobile storage device, a Read Only Memory (ROM), a magnetic disk or an optical disk, or the like, which can store program codes.

Alternatively, the integrated units described above may be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or portions contributing to the related art may be embodied in the form of a software product stored in a storage medium, including several instructions for causing a user equipment to perform all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a removable storage device, a ROM, a magnetic disk, or an optical disk.

The methods disclosed in the method embodiments provided by the application can be arbitrarily combined under the condition of no conflict to obtain a new method embodiment; the features disclosed in the several product embodiments provided by the application can be arbitrarily combined under the condition of no conflict to obtain a new product embodiment; the features disclosed in the several method or apparatus embodiments provided in the present application may be arbitrarily combined without conflict to obtain new method embodiments or apparatus embodiments.

The foregoing is merely an embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of cell search, the method comprising:

determining at least one S-NSSAI to be refused and a refusal reason corresponding to each S-NSSAI according to a registration refusal message returned by the first network aiming at the registration request message; wherein the registration request message carries the at least one S-nsai;

maintaining a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, wherein the first S-nsai is one of the at least one S-nsai; and

performing cell search in a second network based on the current access mode; wherein the second network comprises a network supporting the current access mode; the current access mode has a higher priority than another access mode different from the current access mode.

2. The method of claim 1, wherein maintaining a current access mode based on determining that the reject cause corresponding to the first S-nsai is the first network rejecting the first S-nsai or an authentication or authentication failure for the first S-nsai, further comprising:

and traversing the at least one S-NSSAI until determining that the reject reason corresponding to each S-NSSAI is that the first network rejects the S-NSSAI or authentication failure of the S-NSSAI.

3. The method according to claim 1 or 2, wherein the second network comprises an equivalent network of the same priority as the first network;

the cell search in the second network based on the current access mode comprises the following steps:

deleting the identification of the first network from the stored first network list to obtain a second network list; the first network list comprises the identification of the first network and the identification of the equivalent network with the same priority as the first network;

and sending the second network list to an access layer to instruct the access layer to search cells in an equivalent network indicated by the second network list based on the current access mode.

4. A method according to claim 3, characterized in that the method further comprises:

the method further includes instructing the access layer to disable the current access mode based on determining that no suitable cell is searched for in the equivalent network in the current access mode, and performing a cell search at the first network based on another access mode different from the current access mode.

5. A method according to claim 3, characterized in that the method further comprises:

based on determining that no suitable cell is searched in the equivalent network in the current access mode, transmitting recorded disabling information and a third network list to the access layer, and

instructing the access layer to maintain the current access mode to perform cell search in the network indicated by the third network list based on the current access mode and the disabling information;

6. A method according to claim 3, characterized in that the method further comprises:

based on determining that no suitable cell is searched in the equivalent network according to the current access mode, indicating the access layer to search for a current available network;

selecting a target available network meeting the condition from the current available networks; wherein the condition includes supporting the current access mode;

and sending the identification of the target available network to an access layer to instruct the access layer to search cells on the network indicated by the identification of the target available network based on the current access mode.

7. The method of claim 6, wherein the conditions further comprise: the priority is higher than or equal to the priority of the first network.

8. The method of claim 6, wherein the method further comprises:

the method further includes instructing the access layer to disable the current access mode based on a determination that there is no target available network in the currently available networks that satisfies the condition, and performing a cell search at the first network based on another access mode different from the current access mode.

9. The method of claim 6, wherein the method further comprises:

Transmitting recorded disabling information and a third network list to the access layer to instruct the access layer to maintain the current access mode based on determining that no target available network satisfying the condition exists in the current available networks, and performing cell search at a network indicated by the third network list based on the current access mode and the disabling information;

10. The method according to claim 1 or 2, wherein the second network comprises at least one of: the equivalent network with the same priority as the first network and the target available network meeting the conditions in the current available network; wherein the condition includes supporting the current access mode.

11. The method according to claim 1 or 2, wherein the current access mode is an N1 mode.

12. A method of cell search, the method comprising:

maintaining a current access mode based on determining that a reject cause corresponding to a second S-nsai is a first registration area rejecting the second S-nsai, wherein the second S-nsai is one of the at least one S-nsai; and

performing cell search in a second registration area of the first network based on the current access mode; wherein the second registration area is an area that does not completely overlap with a first registration area, the first network including the first registration area and the second registration area.

13. The method of claim 12, wherein the maintaining the current access mode and the performing a cell search in the second registration area of the first network based on the current access mode comprises:

and sending the received tracking area list to an access layer as a forbidden tracking area list to instruct the access layer to search cells in tracking areas of the first network except for the tracking areas indicated by the forbidden tracking area list based on the current access mode.

14. The method of claim 13, wherein the method further comprises:

transmitting a third network list to the access layer based on determining that no suitable cell is searched for in the tracking areas of the first network other than the tracking area indicated by the forbidden tracking area list, so as to instruct the access layer to perform cell search on the network indicated by the third network list based on the current access mode;

wherein the third network list includes an identification of at least one of the following networks: home network, peer-to-peer home network, user control network, operator control network, network meeting high quality conditions, network not meeting high quality conditions.

15. A cell search apparatus, the apparatus comprising:

a first determining module, configured to determine, according to a registration rejection message returned by the first network for the registration request message, at least one S-nsai that is rejected and a reject reason corresponding to each S-nsai; wherein the registration request message carries the at least one S-nsai;

a first search module, configured to maintain a current access mode based on determining that a reject cause corresponding to a first S-nsai is that the first network rejects the first S-nsai or fails to authenticate or authenticate the first S-nsai, and perform cell search at a second network based on the current access mode; wherein the second network comprises a network supporting the current access mode; the current access mode has a higher priority than another access mode different from the current access mode; wherein the first S-NSSAI is one of the at least one S-NSSAI.

16. A cell search apparatus, the apparatus comprising:

a determining module, configured to determine, according to a registration rejection message returned by the first network for the registration request message, at least one S-nsai that is rejected and a reject reason corresponding to each S-nsai; wherein the registration request message carries the at least one S-nsai;

a second search module, configured to maintain a current access mode based on determining that a reject cause corresponding to a second S-nsai is a reject of the second S-nsai by a first registration area, and perform cell search in a second registration area of the first network based on the current access mode; wherein the second registration area is an area that does not completely overlap with a first registration area, the first network including the first registration area and the second registration area; wherein the second S-NSSAI is one of the at least one S-NSSAI.

17. A user equipment comprising a memory and a processor, the memory storing a computer program executable on the processor, characterized in that the processor implements the method of any one of claims 1 to 11 when executing the program or the processor implements the method of any one of claims 12 to 14 when executing the program.

18. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the method according to any one of claims 1 to 11, or the computer program, when being executed by a processor, implements the method according to any one of claims 12 to 14.

19. A user device comprising a communication module configured to:

20. A user device comprising a communication module configured to: