CN110476457A

CN110476457A - A kind of method for network access and equipment

Info

Publication number: CN110476457A
Application number: CN201780088681.3A
Authority: CN
Inventors: 阮攀; 姜印清; 汤超
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-03-20
Filing date: 2017-03-20
Publication date: 2019-11-19
Also published as: WO2018170697A1

Abstract

This application involves field of communication technology more particularly to the network selection techniques of terminal.The network selecting method of the terminal of the disclosure includes: to obtain equivalent public land mobile network (EPLMN) list；Determine whether the EPLMN in the EPLMN list supports the first access technology；When determining that the EPLMN does not support first access technology, prevent to access the EPLMN using first access technology.

Description

Network access method and equipment

Technical Field

The embodiments of the present application relate to the field of communications technologies, and in particular, to a network access technology of a communication device.

Background

In current Mobile communication networks (e.g., GSM, WCDMA, and LTE networks), a Public Land Mobile Network (PLMN) refers to a Network established and operated by the government or its approved operator for the purpose of providing Land Mobile communication services to the Public. The unique identifier (PLMN ID) of the PLMN is composed of MCC (Mobile Country Code) and MNC (Mobile Network Code).

When a User Equipment (UE) is powered on, the UE selects a PLMN according to a priority order of a stored PLMN list and registers the PLMN to the PLMN network. In most cases, the UE registers with a Home PLMN (Home Public Land Mobile Network, HPLMN), and obtains Network services in the HPLMN. Due to the different coverage areas of different PLMN networks, the UE may roam or handover to other networks during communication. With the continuous development of service cooperation among operators, the application of roaming networks is well developed. The UE may then obtain roaming services from the networks of other operators that have a roaming agreement with the home network operator, in addition to obtaining services on the HPLMN.

In a roaming scenario, an Equivalent PLMN (Equivalent Public Land Mobile Network, EPLMN) refers to a Public Land Mobile Network that is in the same position as that currently selected by the user terminal. An operator may configure the EPLMN network and communication network resource sharing may be implemented between these networks. The EPLMN contained in the list of equivalent PLMNs in the UE is a PLMN considered equivalent to the HPLMN for PLMN selection, cell reselection, and handover.

After registering Public Land Mobile Network (PLMN), the UE downloads and stores a list of equivalent PLMNs from the currently registered PLMN. The UE updates the list of equivalent PLMNs during an attach (attach) or Tracking Area Update (TAU), and specifically, if the UE receives a new list of equivalent PLMNs in an attach/TAU accept (attach/TAU accept) message, the UE updates the list of equivalent PLMNs stored locally.

Currently, the EPLMN does not distinguish access technologies, for example, only a part of EPLMN in the EPLMN list supports LTE services, the remaining part of EPLMN supports UMTS (3G) or GSM (2G) network services, and the operator does not open roaming for LTE network services and open roaming for UMTS and GSM network services due to service needs. When a mobile phone tries to register on the EPLMN by adopting the LTE technology, the LTE network service does not sign a roaming protocol, so that a registration request is rejected by a network every time, the mobile phone is disconnected, and the user experience is influenced.

Disclosure of Invention

A network access method and device are described herein to improve cruising ability of an electronic device.

In a first aspect, an embodiment of the present application provides a network access method. The method comprises the following steps: acquiring an Equivalent Public Land Mobile Network (EPLMN) list; determining whether an EPLMN in the EPLMN list supports a first access technology; and when the EPLMN is determined not to support the first access technology, preventing access to the EPLMN by the first access technology.

In some roaming scenarios, the operator may limit roaming for a particular communication technology of the EPLMN. To avoid the situation where registration of the EPLMN network with a radio access technology that has not opened roaming is denied, it is necessary to consider what may be the appropriate radio access technology. When the EPLMN is determined not to support a certain access technology, the access technology is prevented or avoided from being used for accessing the EPLMN, the access technology can be avoided from being used for initiating an ATTACH registration request to network equipment, and network drop caused by refusal of the registration request is avoided.

In one possible design, the EPLMN is accessed using a second access technology supported by the EPLMN, the second access technology being different from the first access technology. For example, the first access technology is an LTE access technology and the second access technology is a GSM or UMTS access technology. When the EPLMN does not support the LTE access technology, other access technologies supported by the EPLMN can still be adopted to access the EPLMN, so that the user can be ensured to be registered in the roaming area network to obtain network service.

In one possible design, the blocking of the access to the EPLMN using the first access technology may be implemented using the following scheme: preventing delivery of the EPLMN to an Access Stratum (AS) supporting the first access technology. The PLMN selection, cell reselection or handover operation of the terminal is mainly completed under the cooperation of Non-Access Stratum (NAS) and Access Stratum (AS). The NAS does not transmit the EPLMN to the AS supporting the first access technology, so that the terminal can be prevented from trying to register to the EPLMN network by adopting the first access technology, and the network drop caused by refusing of the registration request is further avoided.

In one possible design, the first access technology is a Long Term Evolution (LTE) access technology.

In one possible design, the terminal stores an extended EPLMN list that includes, for each EPLMN, information indicating whether the first access technology is supported by the EPLMN. And inquiring the stored expanded EPLMN list according to the identification of the EPLMN in the EPLMN list, and judging whether the EPLMN supports the first access technology or not according to the inquiry result.

On the other hand, the embodiment of the application provides a terminal, and the terminal has the function of realizing the terminal in the method design. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above-described functions. The modules may be software and/or hardware.

In one possible design, the terminal may be configured to include a memory and a processor. The memory is configured to store program code and data for the processor to perform operations. The processor is configured to obtain a list of Equivalent Public Land Mobile Networks (EPLMNs); determining whether an EPLMN in the EPLMN list supports a first access technology; and when the EPLMN does not support the first access technology, preventing the EPLMN from being accessed by adopting the first access technology.

In another aspect, the present application provides a computer storage medium for storing computer software instructions for the terminal, which includes a program designed to execute the above aspects.

Compared with the prior art, the scheme provided by the application can improve the roaming experience of the terminal user.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of a terminal roaming scenario according to an embodiment of the present application;

FIG. 2 is a diagram of a wireless network protocol stack model according to one embodiment of the present application;

FIG. 3 is a schematic diagram of a NAS providing an EPLMN to an AS;

FIG. 4 is a schematic diagram of a NAS providing an EPLMN to an AS according to one embodiment of the present application;

fig. 5 is a flow chart of a terminal performing PLMN selection, cell selection/reselection or handover according to one embodiment of the present application;

fig. 6 is a block diagram of components of a terminal according to one embodiment of the present application.

Detailed Description

Technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be understood that the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating primary and secondary relationships, and thus are not to be construed as limiting the present application.

In addition, various aspects are described herein in connection with a terminal, which can be a wireless terminal. A terminal can also be called a device, subscriber unit, subscriber station, mobile device, remote station, remote terminal, access terminal, user terminal, communication device, user agent, user device, or User Equipment (UE). A wireless terminal may be a cellular telephone, a satellite telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a Personal Digital Assistant (PDA), a handheld device having wireless connection capability, a computing device, or other processing device connected to a wireless modem. Moreover, various aspects are described herein in connection with a base station. A base station may be utilized for communicating with wireless terminal(s) and may also be referred to as an access point, a node B, or some other terminology. The base station may be implemented as a radio base station of any suitable radio technology, e.g. a BTS (base transceiver station) of a GSM (global system for mobile communications), a NodeB of a HSPA (high speed packet access)/WCDMA (wireless code division multiple access) network, or an eNodeB of an LTE (long term evolution) communication network.

The techniques described herein may be used for various wireless communication networks, e.g., LTE-advanced, Wideband Code Division Multiple Access (WCDMA), global system for mobile communications GSM, to mention just a few possible techniques for radio communication. UTRA (universal terrestrial radio access), E-UTRA (evolved UTRA), GSM, UMTS (universal mobile telecommunications system), LTE and not yet commercially available 5G (fifth generation communication system) are described in documents from an organization named "3 rd generation partnership project" (3 GPP). These wireless technologies and standards are well known in the art and will not be described in detail herein. For clarity, certain aspects of the present technology are described below for LTE, which LTE terminology is used in much of the description below. It should be noted that LTE terminology is used by way of illustration, but the scope of the present invention is not limited to LTE alone.

Fig. 1 depicts a scenario in which the terminal 104 moves from PLMN-1 to an area covered by both PLMN-2 and PLMN-3. In fig. 1, the coverage areas of PLMN-1, PLMN-2 and PLMN-3 are 101, 102 and 103, respectively.

As communication technologies evolve, communication networks can generally support different communication technologies or protocols, with newer generation technologies being compatible with older generation technologies. In fig. 1, the communication system PLMN-1 supports only a fourth generation (LTE) wireless communication technology or protocol. PLMN-2 and PLMN-3 may simultaneously support second generation (GSM/2G), third generation (UMTS/3G) and fourth generation (LTE/4G) wireless communication technologies or protocols.

In some applications, it may be desirable to limit roaming agreements for or to particular communication technologies. For example, a network operator without a 2G license must rely on a roaming agreement with the 2G network operator to provide continuous service to its users. Taking fig. 1 as an example, PLMN-1 is the network of operator a, PLMN-2 is the network of operator B, and PLMN-3 is the network of operator C. Operator a has only 4G networks, while operator B and operator C both have 2G/3G/4G networks. Operator a needs to enter into a roaming agreement with operator B to use operator B's 2G/3G network. But operator B prohibits 4G users of operator a from accessing the 4G network of operator B. Operator C allows 4G users of operator a to access the 4G network of operator C.

The terminal 104 moves from the coverage area 101 to the overlapping area of the coverage area 102 and the coverage area 103, and the equivalent PLMN list created by the Mobility Management Entity (MME) may contain PLMN-2 and PLMN-3. In this case, PLMN-2 may be selected since the terminal 104 may randomly select a PLMN from an equivalent PLMN list for PLMN selection, cell reselection, or handover, but PLMN-2 prohibits the user of operator a (i.e., terminal 104) from accessing its 4G network. Therefore, when the terminal 104 attempts to register to the PLMN-2 by using the LTE technology, the terminal 104 may drop the network each time the LTE network registration request is rejected by the network because the operator a and the operator B do not sign the 4G network roaming agreement.

Generally, the criteria used by the terminal 104 to determine the appropriate cell to camp on is typically the radio conditions between the terminal 104 and the base station providing the cell. For example, if the terminal 104 finds itself in the coverage areas of a first cell and a second cell, and the radio link shared with the first cell is deteriorating, the mobile device will seek to reselect to the second cell. Various messages will be exchanged between the terminal 104 and the core network during the cell selection/reselection procedure. These messages include authentication, registration and configuration messages. In fig. 1, the terminal 104 moves into an area covered by a cell from the third network (PLMN-3). In this case, the terminal 104 will be able to camp on a cell of the third network (PLMN-3) if there is an appropriate roaming agreement between the first network (PLMN-1) and the third network (PLMN-3). The various procedures involved in cell selection and cell reselection for a generic 3GPP compliant network are explained in further detail in 3GPP TS 25.304 and will not be described in detail here.

To avoid the above-mentioned situation where registering the network with a radio access technology (e.g. LTE) that has not opened roaming is rejected. In a roaming scenario, PLMN selection, cell reselection or handover procedures need to consider what may be the appropriate Radio Access Technology (RAT). In some embodiments of the present application, PLMN selection, cell reselection or handover comprises a radio access technology selection procedure.

In order to be able to select a radio access technology, the various parts of the EPLMN list need to become "radio access technology aware". The "radio access technology aware" EPLMN list is referred to herein as an extended EPLMN list. To facilitate differentiation between different radio access technologies, in some embodiments of the application, an indicator or field may be used for indicating the radio access technologies available in the EPLMN. For example, a bit may be used as a flag to indicate whether a RAT is available, which is set to 1 when the EPLMN supports a certain RAT and to 0 when the EPLMN does not support the RAT. Of course, the indicator may be composed of two or more bits. Table one shows an extended EPLMN list assigned with RAT-Supported indicators according to the service provisioning policies of the operator.

Table one example of an extended EPLMN list

In table one, EPLMN and its supported RATs are listed in the extended EPLMN list, where EPLMN-1 supports three RATs of GSM, UMTS, and LTE, and EPLMN-2 supports two RATs of GSM and UMTS, and in conjunction with the above description, the operator of the user of the terminal and the operator providing the EPLMN-2 network storing the extended EPLMN list shown in table one do not subscribe to the 4G network roaming agreement, and thus EPLMN-2 does not support the LTE RAT. Still taking FIG. 1 as an example, EPLMN-1 may be operator C's network and EPLMN-2 may be operator B's network.

In some embodiments, the extended EPLMN list only needs to indicate whether a certain RAT is supported, e.g., only LTE RAT. Table two shows an extended EPLMN list showing LTE-Supported indicators assigned according to the service provisioning policies of the operator.

Second example of Table two extended EPLMN List

EPLMN ID	RAT	LTE-Supported
EPLMN-1	LTE	1
EPLMN-2	LTE	0

In table two, the extended EPLMN list lists EPLMN and its support for LTE RAT, where EPLMN-1 supports LTE RAT and EPLMN-2 does not support LTE RAT, and in conjunction with the above description, the operator of the terminal and the operator providing EPLMN-2 storing the extended EPLMN list shown in table two do not subscribe to 4G network roaming agreement, so EPLMN-2 cannot provide LTE roaming service to the terminal user, that is, EPLMN-2 does not support LTE RAT.

Tables one and two primarily include 3GPP compatible radio access technologies, however, it should be understood that additional radio access technologies such as WLAN (e.g., WiFi), bluetooth, WiMax, etc. may also be included. In one embodiment of the application, the network provides the terminal with an extended EPLMN list as shown in table one and table two. The network may send the extended EPLMN list to the terminal in a location update, attach, routing area update (routing area update) or Tracking Area Update (TAU) process. To send the extended EPLMN list, the network may provide an Information Element (IE) with a list of PLMN identities of equivalent PLMNs in a location update accept, attach accept, routing area update accept, or tracking area update accept message.

In another embodiment of the application, the network provides only a regular EPLMN list to the terminal, which may store the extended EPLMN list as shown in table one or table two in a Subscriber Identity Module (SIM), a universal SIM (usim), or some other non-volatile storage module. The conventional EPLMN list may contain only PLMN IDs, which may include Mobile Country Code (MCC) and Mobile Network Code (MNC). With reference to the above implementation, the network may provide an Information Element (IE) containing a conventional EPLMN list in a location update accept, attach accept, routing area update accept, or tracking area update accept message. And after receiving the conventional EPLMN list issued by the network, the terminal searches the locally stored extended EPLMN list, and accordingly judges the RAT supported by the PLMN in the conventional EPLMN list. Compared with the method that the network side issues the extended EPLMN list, the method that the terminal stores the extended EPLMN list can adopt the current flow of issuing the EPLMN by the network, and the network side does not need to make any modification, so that the convenience of implementation of the scheme is enhanced. Moreover, the number of operators worldwide is limited (several hundreds), and the extended EPLMN list created according to the roaming agreement between these operators occupies little storage space in the terminal, which is convenient for the terminal to manage.

Table three conventional EPLMN list

EPLMN ID
EPLMN-1(MCC-1,MNC-1)
EPLMN-2(MCC-2,MNC-2)

The following describes how a terminal performs PLMN selection, cell reselection or handover operations using the "radio access technology aware" extended EPLMN list.

Taking PLMN selection as an example, PLMN selection can be divided into manual PLMN selection and automatic PLMN selection (see 3GPP TS 23.122 protocol for details). The manual PLMN selection means that a user selects a PLMN to be accessed according to a PLMN list displayed on a terminal, and the PLMN can be displayed according to the priority of each PLMN; the automatic PLMN selection means that the terminal automatically selects the PLMN to be accessed according to the priority order of the PLMN and initiates registration. Cell selection, cell reselection, or handover operations are described in detail in 3GPP protocol specifications and are not described in detail herein.

To describe how the terminal performs PLMN selection, cell reselection or handover operations using the extended EPLMN list, the lower terminal radio protocol stack model is first introduced. Fig. 2 illustrates an exemplary wireless network protocol stack model for network services over a connection-oriented transport session, which includes a Non-Access Stratum (NAS) layer above an Access Stratum (AS). The wireless network protocol stack comprises seven layers: an application layer, a transport layer, an internet layer, a network layer, a link layer, and a physical layer. In one example, an Access Stratum (AS) of a terminal receives a PLMN list provided by a Non-Access Stratum (NAS) and initiates a PLMN search procedure.

The NAS is a network layer that provides network services such as mobility management, connection management, session management, and the like between a Core Network (CN) and a User Equipment (UE). The AS is a link layer that provides lower level services such AS radio resource control, radio link control, medium access control, physical layer services, etc. to the NAS.

As shown in fig. 3, the NAS layer of the multimode terminal 300 supporting GSM/UMTS/LTE has a mobility management module 301 and an EMM (enhanced Evolved Packet System (EPS) mobility management) module 302, and the access layers may be divided into a GSM access layer 303, a UMTS access layer 304, and an LTE access layer 305 according to the access technologies supported by the access layers. Many NAS functions in the UMTS system are inherited to GSM, and thus the mobility management module 301 can be responsible for both GSM and UMTS mobility management. In addition, not shown, the NAS layer of the terminal 300 also supports functions such as an ESM (enhanced session management) function and an SM (session management).

The PLMN selection, cell reselection or handover operation of the terminal is mainly completed under the coordination of the NAS and the AS. Taking PLMN selection as an example, after selecting a PLMN network with the highest priority by the NAS layer of the terminal, notifying a radio resource control module (RRC for short) of the access layer of the selected PLMN network, and determining the cell camping condition under the control of the RRC.

Referring to fig. 3, the mobility management module 301 provides EPLMN (path shown by arrow 306) to the GSM access layer 303, requesting the GSM access layer 303 to camp on the active cell. At the same time, the mobility management module 301 provides the EPLMN (path shown by arrow 307 in the figure) to the UMTS access layer 304, requesting the UMTS access layer 304 to camp on the active cell. The enhanced mobility management module 302 provides the EPLMN to the LTE access layer 305 (the path indicated by arrow 308 in the figure) requesting the LTE access layer 305 to camp on the active cell. If the EPLMN does not support the LTE RAT, the registration request initiated to the LTE network is rejected by the network, and the terminal can drop the network.

To avoid the above-mentioned situation where registering the network with a radio access technology (e.g. LTE) that has not opened roaming is rejected. The NAS may determine whether the EPLMN supports a first access technology (RAT) when providing the EPLMN to the AS, and may prevent or avoid accessing the EPLMN using the first RAT if it is determined that the EPLMN does not support the first RAT, so AS to avoid a situation where registering the network using the first RAT is rejected.

Taking the first RAT as the LTE access technology as an example, referring to fig. 4, assuming that it is determined that the EPLMN does not open the roaming service of the LTE access technology in the NAS layer, that is, it is determined that the EPLMN does not support the LTE RAT, the enhanced mobility management module 302 does not provide the EPLMN to the LTE access layer 305 (the path shown by the arrow 308 in the figure is broken), and thus prevents or avoids accessing the EPLMN using the LTE RAT. Optionally, the terminal may still access the EPLMN using a second access technology supported by the EPLMN, which may be a UMTS access technology or a GSM access technology, and the paths shown by

arrows

306 and 307 are still clear. That is, the mobility management module 301 still provides the EPLMN to the GSM access layer 303 (arrow 306 in the figure), requesting the GSM access layer 303 to camp on the active cell. At the same time, the mobility management module 301 provides the EPLMN to the UMTS access layer 304 (arrow 307 in the figure), requesting the UMTS access layer 304 to camp on the active cell.

Fig. 5 is a flow diagram of a process performed by a terminal for PLMN selection, cell reselection, or handover according to one embodiment of the present application.

Referring to fig. 5, in step 510, the terminal obtains an EPLMN list, which in one example is obtained by a non-access stratum (NAS), and the EPLMN list includes at least one item of EPLMN information. Optionally, step 510 is preceded by determining that PLMN selection, cell reselection, or handover is necessary by the terminal. In one embodiment of the application, the EPLMN list is an extended EPLMN list, which is provided by the network to the terminal as shown in table one and table two. In another embodiment of the present application, the EPLMN list is a conventional EPLMN list, which may contain only PLMN IDs, which may include a Mobile Country Code (MCC) and a Mobile Network Code (MNC).

In step 520, the terminal determines whether the EPLMN in the EPLMN list supports a first access technology (RAT).

As described above, if the EPLMN list is the extended EPLMN list, the terminal may directly know whether the EPLMN supports the first RAT, for example, determine whether the EPLMN supports the first RAT according to the RAT-Supported indicator of the extended EPLMN list shown in table one.

If the EPLMN list is a regular EPLMN list, the terminal may store the extended EPLMN list as shown in table one or table two in a Subscriber Identity Module (SIM), a universal SIM (usim), or some other non-volatile storage module. The terminal queries a stored extended EPLMN list according to the identification of the EPLMN in the EPLMN list, and an example of the extended EPLMN list is shown in the first table or the second table. Wherein the extended EPLMN list includes, for each EPLMN, information indicating whether the first access technology is supported by the EPLMN; and the terminal judges whether the EPLMN supports the first access technology or not according to the query result. For example, the conventional EPLMN list acquired by the terminal is shown in table three, the extended EPLMN list stored by the terminal is shown in table two, the terminal matches EPLMN-2 in the conventional EPLMN list with EPLMN-2 in the extended EPLMN list, and if the matching is successful, it can be known that EPLMN-2 does not support LTE RAT.

In one example, the first RAT is LTE and the non-access stratum (NAS) determines whether the EPLMN supports the first RAT. If it is determined that the EPLMN does not support the first RAT, the process proceeds to step 530, where access to the EPLMN using the first RAT is prevented at step 530. That is, the first RAT is temporarily disabled, the access technology is prevented from being used for accessing the EPLMN network, the access technology can be prevented from being used for initiating an ATTACH registration request to the network device, and a network drop caused by refusing the registration request is further avoided. In one example, the EPLMN may be blocked/not passed to an Access Stratum (AS) that supports the first access technology to disable the first RAT. In one embodiment, when the first RAT is an LTE RAT, the non-access stratum (NAS) may not deliver the EPLMN to the LTE Access Stratum (AS), and in particular, the enhanced mobility management module 302 does not deliver the EPLMN to the LTE access stratum 305 AS shown in fig. 4.

Optionally, in step 540, the terminal accesses the EPLMN using a second access technology supported by the EPLMN, which is different from the first access technology, for example, when the first access technology is LTE, the second access technology may be an access technology of UMTS (e.g., WCDMA). Access to the same EPLMN continues to be allowed with other RATs supported by the EPLMN. In particular, the mobility management module 301 may communicate the EPLMN to the GSM access layer 303 and the UMTS access layer 304 as shown in fig. 4.

If it is determined in step 520 that the EPLMN supports the first RAT, the process proceeds to step 550 where the EPLMN is accessed using the first access technology in step 550. In one example, a non-access stratum (NAS) delivers the EPLMN to an Access Stratum (AS) that supports the first access technology, e.g., LTE, then the NAS layer delivers the EPLMN to the LTE Access Stratum (AS). Specifically, as shown in fig. 3, enhanced mobility management module 302 communicates the EPLMN to LTE access layer 305, while mobility management module 301 may communicate the EPLMN to GSM access layer 303 and UMTS access layer 304.

Fig. 6 is a block diagram of the components of the terminal 104 according to one embodiment of the present application. Referring to fig. 6, the terminal 104 includes a radio communication unit 610, a memory 620, a processor 630, and not shown, and the terminal 104 may further include a display unit, an input unit, a Global Positioning System (GPS) unit, and the like. The processor 630 may be responsible for executing various software programs (e.g., applications and operating systems) to provide computing and processing operations for the terminal 104. The radio communication unit 610 is responsible for communication functions of the electronic device. The radio communication unit 610 establishes a communication channel with a supportable mobile communication network to implement voice telephony, video conferencing, and data communication. The radio communication unit 610 includes a Radio Frequency (RF) transmitter for up-converting and amplifying a transmission signal and an RF receiver for low-noise amplifying and down-converting a reception signal. The radio communication unit 610 includes a cellular communication module (e.g., a third generation (3G) cellular communication module and/or a 4G cellular communication module) and a digital broadcasting module.

The memory 620 is configured to store various data executed and processed in the terminal 104, and an Operating System (OS) and various applications of the electronic device. Memory 620 is implemented with at least one of, but not limited to: RAM, ROM, flash memory, EPROM, and EEPROM. The memory 620 includes a data area and a program area. The data area of the memory 620 stores data generated at the terminal 104 and downloaded from the outside.

The processor 630 controls the terminal 104 to perform PLMN selection, cell reselection or handover, etc. according to one of the above-described embodiments. For example, the processor 630 may execute a method flow as shown in fig. 5 to perform PLMN selection, cell reselection, handover, or the like. The radio communication unit 610 transmits and receives signals necessary to perform one of the above-described embodiments.

The processor described above for performing the embodiments of the present application may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied in hardware or in software instructions executed by a processor. The software instructions may consist of corresponding software modules that may be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC. Additionally, the ASIC may reside in user equipment. Of course, the processor and the storage medium may reside as discrete components in user equipment.

Those skilled in the art will recognize that in one or more of the examples described above, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. Those of skill in the art would readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application. When implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.

The above-mentioned embodiments, objects, technical solutions and advantages of the present application are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present application, and are not intended to limit the scope of the present application, and any modifications, equivalent substitutions, improvements and the like made on the basis of the technical solutions of the present application should be included in the scope of the present application.

Claims

A method for network access, the method comprising:

acquiring an Equivalent Public Land Mobile Network (EPLMN) list;

determining whether an EPLMN in the EPLMN list supports a first access technology;

and when the EPLMN is determined not to support the first access technology, preventing access to the EPLMN by the first access technology.
The method of claim 1, wherein the method further comprises:

accessing the EPLMN using a second access technology supported by the EPLMN, the second access technology being different from the first access technology.
The method of claim 1 or 2, wherein the preventing access to the EPLMN using the first access technology comprises:

preventing delivery of the EPLMN to an Access Stratum (AS) supporting the first access technology.
The method of any of claims 1 to 3, wherein the first access technology is a Long Term Evolution (LTE) access technology.
A method according to any one of claims 1 to 4, wherein the determining whether the EPLMNs in the EPLMN list support a first access technology comprises:

querying a stored extended EPLMN list based on an identification of an EPLMN in the EPLMN list, wherein the extended EPLMN list includes, for each EPLMN, information indicating whether the first access technology is supported by the EPLMN;

and judging whether the EPLMN supports the first access technology or not according to the query result.
A terminal, characterized in that the terminal comprises:

a memory configured to store program codes and data for the processor to perform operations;

a processor configured to: acquiring an Equivalent Public Land Mobile Network (EPLMN) list; determining whether an EPLMN in the EPLMN list supports a first access technology; and when the EPLMN is determined not to support the first access technology, preventing access to the EPLMN by the first access technology.
The terminal of claim 6, wherein the processor is further configured to access the EPLMN using a second access technology supported by the EPLMN, the second access technology different from the first access technology.
The terminal of claim 6 or 7, wherein the processor is configured to prevent delivery of the EPLMN to an Access Stratum (AS) that supports the first access technology.
The terminal of any of claims 6 to 8, wherein the first access technology is a Long Term Evolution (LTE) access technology.
A terminal as claimed in any one of claims 6 to 9, wherein the processor is configured to query a stored extended EPLMN list in dependence on the identity of the EPLMNs in the EPLMN list, wherein the extended EPLMN list includes for each EPLMN information indicating whether the first access technology is supported by the EPLMN; and judging whether the EPLMN supports the first access technology or not according to the query result.