CELL SELECTION AND RESELECTION FOR CLOSED SUBSCRIBER GROUP CELLS

• US 20090238117A1
• Filed: 03/24/2009
• Published: 09/24/2009
• Est. Priority Date: 03/24/2008
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Wang, Peter S., Somasundaram, Shankar, Olvera-Hernandez, Ulises, Mukherjee, Rajat P.
• Granted Patent: US 8,310,946 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04J 11/0093 Neighbour cell search
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

A method for applying a priority of a closed subscriber group (CSG) cell, including receiving priority information for each of a plurality of communication frequencies over which the CSG cell can communicate; storing the priority information at a wireless transmit/receive unit; and applying the priority information to at least one of: taking measurements on a communication frequency, selecting to a CSG cell in the communication frequency, or reselecting to a CSG cell in the communication frequency.

Claims

1. A method for applying a priority of a closed subscriber group (CSG) cell, comprising:

receiving priority information for each of a plurality of communication frequencies over which the CSG cell can communicate;

storing the priority information at a wireless transmit/receive unit (WTRU); and

applying the priority information to at least one of;

taking measurements on a communication frequency, selecting to a CSG cell in the communication frequency, or reselecting to a CSG cell in the communication frequency.

2. The method according to claim 1, wherein the applying includes selecting a highest priority communication frequency.

3. The method according to claim 1, wherein the CSG cell may have a higher priority than a non-CSG cell, on a condition that the CSG cell is configured in a white list of the WTRU.

4. The method according to claim 1, wherein on a condition that a cell reselection is considered between the CSG cell and a non-CSG cell, the non-CSG cell is assumed to have a lower priority than to the CSG cell.

5. A method for grouping closed subscriber group (CSG) cells, comprising:

associating two or more CSG cells into a group based on the purpose of the CSG cell; and

adding a group identifier to a CSG identifier, whereby the group identity can be determined by reading the group identifier.

6. The method according to claim 5, wherein the group identifier is added to a first part of the CSG identifier.

7. The method according to claim 5, wherein a wireless transmit/receive unit can determine whether a CSG cell is acceptable for use by reading the group identifier.

8. The method according to claim 5, wherein the group identifier is configured in a wireless transmit/receive unit as part of the CSG white list configuration.

9. The method according to claim 5, wherein the group identifier is signaled to a wireless transmit/receive unit via one of:

a physical channel, a management information base, or a system information block.

10. A method for indicating a status of a closed subscriber group (CSG) cell, comprising:

providing a one bit indicator on a broadcast channel, the indicator indicating whether the CSG cell is a public CSG cell or a private CSG cell.

11. A method for processing multiple closed subscriber group (CSG) cells by a wireless transmit/receive unit (WTRU), comprising:

making measurements on a CSG frequency;

detecting multiple CSG cells; and

disregarding one of the detected CSG cells if a physical layer cell identifier of the CSG cell does not match an entry in a white list of the CSG cell.

12. A method for processing multiple closed subscriber group (CSG) cells by a wireless transmit/receive unit (WTRU), comprising:

receiving a manual search request from a user of the WTRU;

making measurements on a CSG frequency based on the manual search request;

detecting multiple CSG cells; and

presenting the detected CSG cells to the user, wherein only those CSG cells that can be accessed by the WTRU are presented.

13. The method according to claim 12, wherein a CSG cell can be accessed by the WTRU if a physical layer cell identifier of the CSG cell is in a white list of the WTRU.

14. The method according to claim 12, wherein a CSG cell can be accessed by the WTRU if frequency information for the CSG cell is in a white list of the WTRU.

15. The method according to claim 12, wherein a CSG cell can be accessed by the WTRU if a group identifier of the CSG cell is in a white list of the WTRU.

16. A method for processing multiple closed subscriber group (CSG) cells by a wireless transmit/receive unit (WTRU), comprising:

making measurements on a CSG frequency;

detecting multiple CSG cells;

determining if an identifier of one CSG cell matches an entry in a white list of the WTRU; and

if the CSG identifier does not match an entry in a white list of the WTRU, then moving off the one CSG cell.

17. The method according to claim 16, wherein moving off the one CSG cell includes camping on a macro cell.

18. The method according to claim 16, wherein moving off the one CSG cell includes camping on a macro cell only if a quality the macro cell is above a predetermined threshold.

19. The method according to claim 16, wherein moving off the one CSG cell includes reselecting to another CSG cell.

20. The method according to claim 16, wherein moving off the one CSG cell includes reselecting to a next best CSG cell on a prioritized list of CSG cells maintained by the WTRU.

21. A method for reselecting between closed subscriber group (CSG) cells by a wireless transmit/receive unit (WTRU), comprising:

camping on a first CSG cell; and

examining an intra-frequency reselection indicator, wherein if set, the intra-frequency reselection indicator indicates that an entire frequency is barred from reselection by the WTRU.

22. The method according to claim 21, further comprising:

ignoring the intra-frequency reselection indicator to search for other cells within the same frequency.

23. A method for manual closed subscriber group (CSG) cell selection by a wireless transmit/receive unit (WTRU), comprising:

making measurements on a CSG frequency;

detecting multiple CSG cells;

filtering the detected CSG cells based on radio-related criteria; and

presenting the filtered CSG cells to a non-access stratum for further evaluation.

24. The method according to claim 23, wherein the presenting includes presenting only those CSG cells which are below a certain threshold.