Apparatus and method for automatically searching for low-power base station supporting access of registered user in mobile communication system

• US 20100069069A1
• Filed: 09/17/2009
• Published: 03/18/2010
• Est. Priority Date: 09/18/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jeong, Kyeong-In, Lee, Ok-Seon, Kwun, Jong-Hyung, Cha, Hwa-Jin, Kwon, Sung-Oh, Lee, Neung-Hyung, Cheon, Jung-Hoon
• Granted Patent: US 9,185,636 B2
• Time in Patent Office: Days
• US Class Current: 455/435.200
• 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 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An apparatus and method for automatically searching for a low-power Base Station (BS) supporting access of a registered user in a mobile communication system includes a method of performing automatic search on a Closed Subscriber Group (CSG) cell by a User Equipment (UE). The method includes determining by the UE whether automatic search needs to be performed on the CSG cell. The method also includes, if it is determined that automatic search does not need to be performed on the CSG cell, turning off by the UE a CSG cell automatic search function of the UE by emptying a first white list including CSG Identifiers of accessible CSG cells.

Claims

1. A method of performing automatic search on a Closed Subscriber Group (CSG) cell by a User Equipment (UE), the method comprising:

determining by the UE whether automatic search needs to be performed on the CSG cell; and

if it is determined that automatic search does not need to be performed on the CSG cell, turning off by the UE a CSG cell automatic search function of the UE by emptying a first white list including CSG IDentifiers (IDs) of accessible CSG cells.

2. The method of claim 1, further comprising:

if it is determined that automatic search needs to be performed on the CSG cell, determining by the UE whether the first white list is empty; and

if the first white list is empty, turning on by the UE the CSG cell automatic search function of the UE by recovering the first white list.

3. The method of claim 2, wherein, in the recovering of the first white list, a second white list including CSG IDs of all CSG cells to which the UE is registered is used so that the UE copies all of the CSG IDs included in the second white list and inserts the copied CSG IDs into the first white list.

4. The method of claim 2, wherein, in the recovering of the first white list, a second white list including CSG IDs of all CSG cells to which the UE is registered is used so that the UE copies CSG IDs of currently accessible CSG cells among CSG IDs included in the second white list and inserts the copied CSG IDs into the first white list.

5. The method of claim 1, wherein the determining of whether automatic search needs to be performed on the CSG cell comprises:

determining by the UE that automatic search does not need to be performed on the CSG cell if the UE does not support a CSG function, or even if the UE supports the CSG function, if an accessible CSG cell does not exist nearby or the UE is a high speed UE; and

determining by the UE that automatic search needs to be performed on the CSG cell if the UE supports the CSG function and if the accessible CSG cell exists nearby or the UE is switched from the high speed UE to a low speed UE.

6. The method of claim 5, wherein the determining of whether automatic search needs to be performed on the CSG cell comprises:

if a pre-stored fingerprint and current broadcast information have the same information, determining by the UE that the accessible CSG cell exists nearby; and

if the pre-stored fingerprint and the current broadcast information do not have the same information, determining by the UE that the accessible CSG cell does not exist nearby.

7. An apparatus for performing automatic search on a Closed Subscriber Group (CSG) cell by a User Equipment (UE), the apparatus comprising:

a CSG automatic search unit for determining whether automatic search needs to be performed on the CSG cell, and for turning off an CSG cell automatic search function of the UE by emptying a first white list if it is determined that automatic search does not need to be performed on the CSG cell; and

the first white list including CSG IDentifiers (IDs) of accessible CSG cells of the UE.

8. The apparatus of claim 7, wherein the CSG automatic search unit determines whether the first white list is empty if it is determined that automatic search needs to be performed on the CSG cell, and turns on the CSG cell automatic search function of the UE by recovering the first white list if the first white list is empty.

9. The apparatus of claim 8, wherein the CSG automatic search unit uses a second white list including CSG IDs of all CSG cells to which the UE is registered to recover the first white list by copying all of CSG IDs included in the second white list and then by inserting the copied CSG IDs into the first white list.

10. The apparatus of claim 8, wherein the CSG automatic search unit uses a second white list including CSG IDs of all CSG cells to which the UE is registered to recover the first white list by copying CSG IDs of currently accessible CSG cells among CSG IDs included in the second white list and then by inserting the copied CSG IDs into the first white list.

11. The apparatus of claim 7, wherein the CSG automatic search unit determines that automatic search does not need to be performed on the CSG cell if the UE does not support a CSG function, or even if the UE supports the CSG function, if an accessible CSG cell does not exist nearby or the UE is a high speed UE, whereas determines that automatic search needs to be performed on the CSG cell if the UE supports the CSG function and if the accessible CSG cell exists nearby or the UE is switched from the high speed UE to a low speed UE.

12. The apparatus of claim 11, wherein the CSG automatic search unit determines that the accessible CSG cell exists nearby if a pre-stored fingerprint and current broadcast information have the same information, whereas determines that the accessible CSG cell does not exist nearby if the pre-stored fingerprint and the current broadcast information do not have the same information.

13. A method of updating a white list of a User Equipment (UE) by a network, the method comprising:

obtaining by the network at least one information selected from a Closed Subscriber Group (CSG) IDentifier (ID) of a newly installed CSG Base Station (BS) and a UE ID of a UE registered to the newly installed CSG BS;

if the UE enters into the coverage of a macro BS, obtaining by the network at least one information selected from a UE ID of the entering UE and a CSG ID identifying an accessible CSG BS and included in the white list managed by the entering UE;

determining by the network whether a CSG BS accessible by the entering UE exists near the macro BS on the basis of the obtained information; and

transmitting by the network a white list update command to the entering UE according to the determination result.

14. The method of claim 13, wherein the network is any one of the macro BS, a Mobility Management Entity (MME), the newly installed CSG BS, a Serving GPRS Support Node (SGSN), a Mobile Switching Center (MSC), an Operations &

Maintenance (O&

M), and an Access Control Router (ACR).

15. The method of claim 13, wherein the transmitting of the white list update command to the entering UE comprises:

if the CSG BS accessible by the entering UE does not exist near the macro BS, transmitting by the network the white list update command to the entering UE to empty the white list; and

if the CSG BS accessible by the entering UE exists near the macro BS but the white list of the entering UE is empty, transmitting by the network the white list update command to the entering UE to recover the white list.

16. A system comprising:

a network for transmitting a white list update command to a User Equipment (UE),

wherein the network obtains at east one information selected from a Closed Subscriber Group (CSG) Identifier (ID) of a newly installed CSG Base Station (BS) and a UE ID of a UE registered to the newly installed CSG BS,

wherein, if the UE enters into the coverage of a macro BS, the network obtains at least one information selected from a UE ID of the entering UE and a CSG ID identifying an accessible CSG BS and included in a white list managed by the entering UE,

wherein the network determines whether a CSG BS accessible by the entering UE exists near the macro BS on the basis of the obtained information, and

wherein the network transmits a white list update command to the entering UE according to the determining result; and

the UE for updating the white list according to the white list update command received from the network.

17. The system of claim 16, wherein the network comprises one of the macro BS, a Mobility Management Entity (MME), the newly installed CSG BS, a Serving GPRS Support Node (SGSN), a Mobile Switching Center (MSC), an Operations &

Maintenance (O&

M), and an Access Control Router (ACR).

18. The system of claim 16,

wherein, if the CSG BS accessible by the entering UE does not exist near the macro BS, the network transmits the white list update command to the entering UE to empty the white list, and

wherein, if the CSG BS accessible by the entering UE exists near the macro BS but the white list of the entering UE is empty, the network transmits the white list update command to the entering UE to recover the white list.

19. The system of claim 16, wherein the UE comprises a CSG automatic search unit for determining whether automatic search needs to be performed on the CSG cell, and for turning off an CSG cell automatic search function of the UE by emptying a first white list if it is determined that automatic search does not need to be performed on the CSG cell;

and

the first white list including CSG IDentifiers (IDs) of accessible CSG cells of the UE.

20. The system of claim 19, wherein the CSG automatic search unit determines whether the first white list is empty if it is determined that automatic search needs to be performed on the CSG cell, and turns on the CSG cell automatic search function of the UE by recovering the first white list if the first white list is empty