MULTI-CELL WTRUS CONFIGURED TO PERFORM MOBILITY PROCEDURES AND METHODS

• US 20090270103A1
• Filed: 04/24/2009
• Published: 10/29/2009
• Est. Priority Date: 04/25/2008
• 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 R., DiGirolamo, Rocco, Pelletier, Benoit
• Granted Patent: US 9,226,205 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/0069 in case of dual connectivity, e.g. decoupled uplink/downlink
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

Dual-cell or multi-cell Wireless Transmit Receive Units (WTRUS) configured to implement mobility procedures are described. The WTRU configurations implement methods to optimize and allow mobility for the procedures of cell search and cell reselection, measurement reporting and inter-frequency handovers, compressed mode measurements, and soft handovers.

Claims

1. A method for a multi-carrier wireless transmit receive unit (WTRU) comprising:

receiving downlink communications over a plurality of carriers; and

performing mobility procedures using at least one of the plurality of carriers.

2. The method of claim 1, wherein the performing mobility procedures includes performing a cell reselection by:

receiving a carrier priority indicating a priority of the carriers; and

camping on a cell associated with a highest carrier priority.

3. The method of claim 2, wherein camping on the cell with the highest priority carrier includes camping on an anchor cell.

4. The method of claim 1 where the receiving is on two carriers further comprising:

receiving an indication that one of the carriers is a supplementary carrier and one of the carriers is an anchor carrier, the anchor carrier associated with an anchor cell, and the supplementary carrier associated with a supplementary cell.

5. The method of claim 4, wherein the performing mobility procedures includes cell selection wherein the cell selection comprises camping on the anchor cell.

6. The method of claim 4 wherein the performing mobility procedures includes:

scanning radio frequency (RF) carriers for a new carrier;

detecting a suitable cell associated with the new RF carrier; and

reselecting to receive downlink communication over the new RF carrier on the condition that the new carrier has a certain priority.

7. The method of claim 6 wherein the scanning is performed based on a comparison of a signal level or quality of the anchor cell or the supplementary cell with a threshold.

8. The method of claim 6 wherein the scanning is performed on carriers having the same or higher carrier priority.

9. The method of claim 4 wherein performing mobility procedures comprises:

receiving discontinuous reception (DRX) from the supplementary cell in the supplementary corresponding measurement occasions; and

making inter-frequency measurements on the supplementary carrier.

10. The method of claim 4 wherein the performing mobility procedures comprises performing supplementary carrier handovers.

11. The method of claim 4 wherein the performing mobility procedures comprises taking measurements of carriers within a sector other than sectors for the anchor carrier and supplementary carrier.

12. The method of claim 11 wherein the taking measurements of carriers is triggered based on a comparison of a common pilot channel (CPCH) signal quality of either the anchor cell or the supplementary cell with a threshold.

13. The method of claim 11 wherein the performing mobility procedures further comprises:

monitoring a Channel Quality Indication (CQI); and

triggering a CQI reporting the quality of the carrier in the same sector or a neighboring sector.

14. The method of claim 11 wherein the performing mobility procedures further comprises:

monitoring a number of failed downlink (DL) Media Access Control (MAC) Protocol Data Units (PDUs) on the supplementary cell.

15. The method of claim 11 wherein performing mobility procedures further comprises:

checking at least one of whether the number of failed DL MAC PDUs is above a threshold during a configured period of time, and whether the number of consecutive failed DL MAC PDUs is above a threshold.

16. The method of claim 11 further comprising reporting neighboring cell carrier measurements.

17. The method of claim 4 wherein the performing mobility procedures includes handing over to a new anchor carrier associated with a new anchor cell.

18. The method of claim 17, wherein the handing over comprises:

maintaining a connection with the supplementary cell associated with the supplementary carrier while establishing synchronization and physical channels in the new anchor cell.

19. The method of claim 18, wherein the handing over further comprises:

establishing a new supplementary cell once the new anchor cell has been established if the supplementary carrier is used as the new anchor carrier.

20. The method of claim 18, wherein the handing over further comprises:

flushing Hybrid Automatic Repeat Request (HARQ)processes corresponding to the anchor cell.

21. The method of claim 17 wherein the handing over further comprises:

flushing a Hybrid Automatic Repeat Request (HARQ)processes corresponding to the anchor and supplementary cells.

22. The method of claim 4 wherein the performing mobility procedures includes performing compressed mode measurements.

23. The method of claim 22 wherein performing compressed mode measurements includes:

applying measurement gaps to the supplementary carrier received in a measurement control message;

deactivating the supplementary carrier during a measurement cap, and performing other frequency or inter-Radio Access Technology (RAT).

24. The method of claim 1 where each carrier is associated with a cell wherein the performing mobility procedures comprises performing public land mobile network (PLMN) selection that includes:

scanning each of the plurality of carriers to determine a strongest cell from among the cells associated the plurality of carriers;

determining the PLMN associated with the strongest cell; and

selecting the PLMN determined to be associated with the strongest cell.

25. A multi-carrier wireless transmit receive unit (WTRU) comprising:

a receiver component configured to receive downlink communications over a plurality of carriers; and

a processing component configured to perform mobility procedures using received signals from at least one of the plurality of carriers.

26. The WTRU of claim 25 wherein the receiver component includes an antenna and a receiver configured to receive downlink communications over all of the plurality of carriers.

27. The WTRU of claim 25 wherein the receiver component includes a plurality of antennas and associated receivers configured such that one antenna and associated receiver is configured to receive downlink communications over one of the plurality of carriers.

28. The WTRU of claim 25 wherein the processing component is configured to perform a cell reselection by processing a received carrier priority indicating a priority of the carriers and controlling the receiving component to camp on a cell associated with a highest carrier priority.

29. The WTRU of claim 25 wherein the receiver component is configured to receive an indication that one of the carriers is a main carrier that is associated with a main cell and the other carriers are associated with supplementary cells.

30. The WTRU of claim 29 wherein the processing component is configured:

to control the receiver component to scan radio frequency (RF) carriers for a new carrier;

to detect a suitable cell associated with the new RF carrier; and

to control the receiver component to reselect to receive downlink communication over the new RF carrier on the condition that the new carrier has a certain priority.

31. The WTRU of claim 29 wherein the processing component is configured to control the receiver component to scan carriers having at least a selected degree of carrier priority.

32. The WTRU of claim 29 wherein the processing component is configured to control the receiver component to receive discontinuous reception (DRX) from a supplementary cell in a corresponding measurement occasions and to make inter-frequency measurements on a supplementary carrier.

33. The WTRU of claim 29 wherein the processing component is configured to control the receiver component to perform supplementary carrier handovers while maintaining the main carrier reception.

34. The WTRU of claim 29 wherein the processing component is configured to control the receiver component to take measurements of carriers within a sector other than a sector for the main carrier such that the taking measurements of carriers is triggered based on a comparison of a common pilot channel (CPCH) signal quality of the main cell with a threshold.

35. The WTRU of claim 25 further comprising a transmitter component wherein the processing component is configured to control the receiver component to monitor a Channel Quality Indication (CQI), and the transmission of a CQI report to report the quality of reception on the plurality of carriers.

36. The WTRU of claim 29 wherein the processing component is configured to control the receiver component to monitor a number of failed downlink (DL) Media Access Control (MAC) Protocol Data Units (PDUs) on the supplementary cells.

37. The WTRU of claim 29 wherein the processing component is configured to control the receiver component to hand over communications from the main carrier to a new main carrier associated with a new main cell.

38. The WTRU of claim 36 wherein the processing component is configured to control the receiver component to establish a new supplementary cell once the new main cell has been established if a supplementary carrier is used as the new main carrier.

39. The WTRU of claim 29 wherein the processing component is configured to control the receiver component to perform compressed mode measurements by

applying measurement gaps to a supplementary carrier received in a measurement control message;

deactivating the supplementary carrier during a measurement cap, and

performing other frequency or inter-Radio Access Technology (RAT).

40. The WTRU of claim 25 where each carrier is associated with a cell wherein the processing component is configured to control the receiver component to perform public land mobile network (PLMN) selection that includes:

scanning each of the plurality of carriers to determine a strongest cell from among the cells associated the plurality of carriers;

determining the PLMN associated with the strongest cell; and

selecting the PLMN determined to be associated with the strongest cell.