METHOD AND APPARATUS FOR SEARCHING FOR NETWORK

• US 20150094058A1
• Filed: 10/24/2014
• Published: 04/02/2015
• Est. Priority Date: 09/29/2013
• Status: Active Grant

• Current Assignee: Huawei Device Company Limited (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Device Company Limited (Huawei Investment & Holding Co., Ltd.)
• Inventors: Dang, Shujun, Duan, Xiaoyan, Jin, Hui, Wang, Jian, Chen, Xiaoyan, Jiang, Yinqing, Fa, Yongtao, Liu, Xiaojian
• Granted Patent: US 9,313,726 B2
• Time in Patent Office: Days
• US Class Current: 455/434
• CPC Class Codes: H04W 48/02 Access restriction performed under specific conditions
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

The present invention discloses a method and an apparatus for searching for a network. The method includes: determining that a user equipment (UE) camping on a cell of a current public land mobile network (PLMN) is in an access barred state; determining that the UE cannot be successfully registered with the current PLMN; and performing a PLMN search. In the method and the apparatus for searching for a network according to embodiments of the present invention, if it is determined that the UE normally camping on the cell of the current PLMN is in the access barred state and cannot be successfully registered with the current PLMN, the PLMN search is performed, so that when the UE is in the access barred state, the UE can still perform the PLMN search, and can further select a new PLMN for access and execute a normal service, thereby improving user experience

Claims

1. A method for searching for a network, the method comprising:

determining that a user equipment (UE) camping on a cell of a current public land mobile network (PLMN) is in an access barred state;

determining that the UE cannot be successfully registered with the current PLMN; and

performing a PLMN search.

2. The method according to claim 1, wherein before performing a PLMN search, the method further comprises:

determining whether the current PLMN is a normal PLMN, wherein the normal PLMN comprises;

a registered public land mobile network (RPLMN) with which the UE is previously successfully registered, a home public land mobile network (HPLMN) of the UE or an equivalent home public land mobile network (EHPLMN) of the UE; and

the performing a PLMN search comprises;

if it is determined that the current PLMN is not the normal PLMN, performing the PLMN search.

3. The method according to claim 1, wherein:

before performing a PLMN search, the method further comprises;

starting a timer; and

performing a PLMN search comprises;

if the timer times out and the UE is still in the access barred state, performing the PLMN search.

4. The method according to claim 1, wherein performing a PLMN search comprises:

performing the PLMN search by using a manner in which a shortest PLMN search period is used as a start point and a PLMN search period is gradually extended, wherein the shortest PLMN search period is shorter than a PLMN search period that is used when the UE can execute a normal service;

or

performing the PLMN search by using a search period shorter than a PLMN search period that is used when the UE can execute a normal service.

5. A method for searching for a network, the method comprising:

determining that a user equipment (UE) camping on a cell of a current public land mobile network (PLMN) is in an access barred state;

switching to a limited service state; and

performing a PLMN search.

6. The method according to claim 5, wherein:

before switching to a limited service state, the method further comprises;

determining that the current PLMN is not a home public land mobile network (HPLMN) of the UE and the PLMN is not an equivalent home public land mobile network (EHPLMN) of the UE; and

determining that the UE is not in a normal roaming state; and

switching to a limited service state comprises;

if the current PLMN is neither the HPLMN of the UE nor the EHPLMN of the UE and the UE is not in the normal roaming state, switching to the limited service state.

7. The method according to claim 6, wherein determining that the UE is not in a normal roaming state comprises:

determining that the UE is not in the normal roaming state if at least one of the following cases exists;

The UE cannot be successfully registered with the current PLMN, the current PLMN is not a registered public land mobile network RPLMN with which the UE is previously successfully registered, a PLMN selector list of the UE does not comprise the current PLMN, the UE is not in a roaming state, roaming configuration information of the UE does not comprise information about the current PLMN, or a network type of the current PLMN is not a type of a network in which the UE can normally roam.

8. The method according to claim 5, wherein:

before switching to a limited service state, the method further comprises;

starting a timer; and

switching to a limited service state comprises;

if the timer times out and the UE is still in the access barred state, switching to the limited service state.

9. The method according to claim 5, wherein performing a PLMN search comprises:

performing the PLMN search by using a manner in which a shortest PLMN search period is used as a start point and a PLMN search period is gradually extended, wherein the shortest PLMN search period is shorter than a PLMN search period that is used when the UE can execute a normal service;

or

performing the PLMN search by using a search period shorter than a PLMN search period that is used when the UE can execute a normal service.

10. A terminal device camping on a cell of a current public land mobile network (PLMN), the device comprising:

a subscriber identity module, configured to store an access control class (ACC) of the terminal device; and

a processor, configured to;

determine that the terminal device is in an access barred state according to system information of the current PLMN and the ACC of the terminal device stored in the subscriber identity module,

determine that the terminal device cannot be successfully registered with the current PLMN, and

perform a PLMN search.

11. The terminal device according to claim 10, wherein the processor is further configured to:

before performing the PLMN search, determine whether the current PLMN is a normal PLMN, wherein the normal PLMN comprises;

a registered public land mobile network (RPLMN) with which the terminal device is previously successfully registered, a home public land mobile network (HPLMN) of the terminal device or an equivalent home public land mobile network (EHPLMN) of the terminal device; and

if it is determined that the current PLMN is not the normal PLMN, perform the PLMN search.

12. The terminal device according to claim 10, wherein the processor is further configured to:

start a timer before performing the PLMN search; and

if the timer times out and the terminal device is still in the access barred state, perform the PLMN search.

13. The terminal device according to claim 10, wherein the processor is configured to:

perform the PLMN search by using a manner in which a shortest PLMN search period is used as a start point and a PLMN search period is gradually extended, wherein the shortest PLMN search period is shorter than a PLMN search period that is used when the terminal device can execute a normal service;

or

perform the PLMN search by using a search period shorter than a PLMN search period that is used when the terminal device can execute a normal service.

14. A terminal device camping on a cell of a current public land mobile network (PLMN), the device comprising:

a subscriber identity module, configured to store an access control class (ACC) of the terminal device; and

a processor, configured to;

determine that the terminal device is in an access barred state according to system information of the current PLMN and the ACC of the terminal device stored in the subscriber identity module,

switch to a limited service state, and

perform a PLMN search.

15. The terminal device according to claim 14, wherein the processor is further configured to:

before switching to the limited service state, determine that the current PLMN is not a home public land mobile network (HPLMN) of the terminal device and the current PLMN is not an equivalent home public land mobile network (EHPLMN) of the terminal device;

determine that the terminal device is not in a normal roaming state; and

if the current PLMN is neither the HPLMN of the terminal device nor the EHPLMN of the terminal device, and the terminal device is not in the normal roaming state, switch to the limited service state.

16. The terminal device according to claim 15, wherein the processor is configured to determine that the terminal device is not in the normal roaming state if at least one of the following cases exists:

the terminal device cannot be successfully registered with the current PLMN, the current PLMN is not a registered public land mobile network RPLMN with which the terminal device is previously successfully registered, a PLMN selector list of the terminal device does not comprise the current PLMN, the terminal device is not in a roaming state, roaming configuration information of the terminal device does not comprise information about the current PLMN, or a network type of the current PLMN is not a type of a network in which the terminal device can normally roam.

17. The terminal device according to claim 14, wherein the processor is further configured to:

start a timer before switching to the limited service state; and

if the timer times out and the terminal device is still in the access barred state, switch to the limited service state.

18. The terminal device according to claim 14, wherein the processor is configured to:

perform the PLMN search by using a manner in which a shortest PLMN search period is used as a start point and a PLMN search period is gradually extended, wherein the shortest PLMN search period is shorter than a PLMN search period that is used when the terminal device can execute a normal service;

or

perform the PLMN search by using a search period shorter than a PLMN search period that is used when the terminal device can execute a normal service.