CONTROLLING INTER-CELL INTERFERENCE IN FORWARD ACCESS CHANNEL (CELL_FACH) STATE

• US 20120250521A1
• Filed: 03/30/2012
• Published: 10/04/2012
• Est. Priority Date: 04/01/2011
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Marinier, Paul, Pani, Diana, Cave, Christopher
• Granted Patent: US 9,516,657 B2
• Time in Patent Office: Days
• US Class Current: 370/241
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

Since common E-DCH resources may be assigned from a single Node B, uplink macro-diversity may not be possible between neighboring Node B'"'"'s. In addition, a user equipment (UE) assigned a common E-DCH resource may not be allowed to perform cell reselection. Thus, maintaining the assignment of a common E-DCH resource to a given UE for more than a few hundred milliseconds may result in unacceptable inter-cell interference, for example, when the UE moves closer to a neighboring cell controlled by a non-serving Node B. To overcome inter-cell interference and allow a more extensive utilization of the Cell_FACH state, a method may be used to detect and/or control inter-cell interference.

Claims

1. A method for detecting inter-cell interference, the method comprising:

obtaining, via a WTRU, a set of characteristics that identifies interference to a common enhanced dedicated cannel (E-DCH) resource;

determining a condition to apply an interference indication; and

receiving the interference indication using the set of characteristics of the interference.

2. The method of claim 1, wherein receiving the interference indication using the set of characteristics occurs when the condition is met.

3. The method of claim 1, further comprising applying the interference indication when the condition is met.

4. The method of claim 1, wherein receiving the interference indication comprises receiving the interference indication from an enhanced relative grant channel (E-RGCH) using the set of characteristics.

5. The method of claim 1, wherein obtaining a set of characteristics comprises receiving a mapping between the common E-DCH resource and the set of characteristics.

6. The method of claim 1, wherein obtaining a set of characteristics comprises receiving characteristics for all common E-DCH resources.

7. The method of claim 1, wherein obtaining a set of characteristics comprises receiving characteristics for a subset of common E-DCH resources.

8. The method of claim 1, wherein the set of characteristics comprises a signature sequence and a channelization code.

9. The method of claim 1, wherein determining a condition to apply the interference indication comprises determining a signal level or signal quality that should be met or exceeded.

10. The method of claim 1, wherein determining a condition to apply the interference indication comprises determining a signal level or signal quality of a reference signal that is transmitted should meet or exceed.

11. The method of claim 1, wherein determining a condition to apply the interference indication comprises determining a signal level or signal quality that a victim cell signal should meet or exceed.

12. The method of claim 1, wherein the interference indication indicates that a victim cell is experiencing inter-cell interference.

13. A method of controlling inter-cell interference, the method comprising:

obtaining, via a WTRU, a set of characteristics that identifies interference to a common enhanced dedicated cannel (E-DCH) resource;

receiving an interference indication using the set of characteristics of the interference; and

applying the interference indication when a condition is met.

14. The method of claim 13, wherein applying the interference indication comprises reducing a grant.

15. The method of claim 13, wherein applying the interference indication comprises reducing a maximum enhanced dedicated physical data channel (E-DPDCH) power.

16. The method of claim 13, wherein applying the interference indication comprises ceasing to transmit on E-DPDCH.

17. The method of claim 13, wherein applying the interference indication comprises deactivating a hybrid automatic repeat request (HARD) process that was used in a previous transmission.

18. The method of claim 13, wherein receiving the interference indication using the set of characteristics occurs when the condition is met.

19. A wireless transmit/receive unit (WTRU) for detecting inter-cell interference, the WTRU comprising:

a receiver configured to obtain a set of characteristics for an interference applicable to a common enhanced dedicated cannel (E-DCH) resource; and

a processor configured to;

determine a condition to apply an interference indication; and

receive the interference indication using the set of characteristics of the interference.

20. The WTRU claim 19, wherein the processor determines a condition to apply the interference indication comprises determining a signal level or signal quality that should be met or exceeded.