MAINTAINING TIME ALIGNMENT WITH MULTIPLE UPLINK CARRIERS

• US 20150103811A1
• Filed: 12/22/2014
• Published: 04/16/2015
• Est. Priority Date: 01/08/2010
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Marinier, Paul, Anepu, Bhaskar M., Pelletier, Ghyslain, Olesen, Robert L.
• Granted Patent: US 10,477,493 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04L 27/2646 using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Maintaining time alignment with multiple carriers is contemplated. A group of uplink carriers (UL CC sets) that operate with a single Timing Advance (TA) may be determined, and a TA value may be applied to a specific UL CC set. A wireless transmit/receive unit'"'"'s (WTRU) capability of using multiple TAs may define a group index of a few bits for each UL CC set. A TA Command received in a Random Access Response message may be used to apply the TA value to each UL carrier of the UL CC set. The WTRU may determine which UL CC set the TA value applies to based on which DL carrier the command was transmitted from. The WTRU may determine which UL CC set the TA value applies to based on the Group Index being explicitly provided in the command. The WTRU may release multi-CC configurations upon Time Alignment Timer (TAT) expiry.

Claims

1. A wireless transmit/receive unit (WTRU), comprising:

a processor, the processor configured, at least to;

determine one or more sets of serving cells, each of the one or more sets of serving cells including at least one serving cell with a configured uplink component carrier (UL CC sets), each of the UL CC sets respectively associated with a group index of one or more group indices, each UL CC set of the one or more UL CC sets respectively including one or more uplink carriers that are associated with a same group index with which the UL CC set is associated, each of the one or more uplink carriers that are included in a respective UL CC set being configured to operate with a same Timing Advance (TA) of one or more Timing Advances (TAs), each of the UL CC sets having a respectively associated reference carrier providing a TA of the one or more TAs;

receive a first TA value via a first reference carrier, the first reference carrier associated with a first UL CC set; and

apply the first TA value to the one or more uplink carriers that are included in the first UL CC set.

2. The WTRU of claim 1, wherein the processor is further configured to:

selecting the first UL CC set;

identifying at least one of the one or more uplink carriers of the first UL CC set that are capable of random access channel (RACH) communication;

initiating a RACH communication on at least one of the identified one or more uplink carriers of the first UL CC set; and

receiving the first TA value in response to the RACH communication.

3. The WTRU of claim 2, wherein the first TA value is applied using a Timing Advance Command received in a Random Access Response message received in response to the RACH communication.

4. The WTRU of claim 2, wherein the first UL CC set has an associated Time Alignment Timer (TAT) and the processor is further configured to either start the TAT or restart the TAT.

5. The WTRU of claim 3, wherein the Timing Advance Command further includes a Timing Advance Command Medium Access Control (MAC) control element.

6. The WTRU of claim 4, wherein the first UL CC set includes at least one uplink carrier with a dedicated physical uplink control channel (PUCCH) configuration, and the processor is further configured to cease transmitting on a resource corresponding to the PUCCH upon an expiration of the TAT.

7. The WTRU of claim 4, wherein the first UL CC set includes at least one uplink carrier with at least one of a dedicated physical uplink control channel (PUCCH) configuration or a sounding and reference signal (SRS) configuration, and the processor is further configured to remove at least a part of either the PUCCH configuration or the SRS configuration upon an expiration of the TAT.

8. The WTRU of claim 4, wherein the processor is further configured to remove one or more Hybrid Automatic Repeat Request (HARQ) buffers corresponding to the first UL CC set upon an expiration of the TAT.

9. The WTRU of claim 1, wherein the first reference carrier is a first downlink (DL) carrier, the first DL carrier being associated with the first UL CC set.

10. The WTRU of claim 2, wherein the initiating the RACH communication on the at least one of the identified one or more uplink carriers of the first UL CC set includes initiating a contention free based RACH procedure.

11. A method for establishing timing advance, comprising:

determining one or more sets of serving cells, each of the one or more sets of serving cells including at least one serving cell with a configured uplink component carrier (UL CC sets), each of the UL CC sets respectively associated with a group index of one or more group indices, each UL CC set of the one or more UL CC sets respectively including one or more uplink carriers that are associated with a same group index with which the UL CC set is associated, each of the one or more uplink carriers that are included in a respective UL CC set being configured to operate with a same Timing Advance (TA) of one or more Timing Advances (TAs), each of the UL CC sets having a respectively associated reference carrier providing a TA of the one or more TAs;

receiving a first TA value via a first reference carrier, the first reference carrier associated with a first UL CC set; and

applying the first TA value to the one or more uplink carriers that are included in the first UL CC set.

12. The method of claim 11, further comprising:

selecting the first UL CC set;

identifying at least one of the one or more uplink carriers of the first UL CC set that are capable of random access channel (RACH) communication;

initiating a RACH communication on at least one of the identified one or more uplink carriers of the first UL CC set; and

receiving the first TA value in response to the RACH communication.

13. The method of claim 11, further comprising:

executing at least one of a start or a restart of a Time Alignment Timer (TAT), the TAT being associated with the first UL CC set.

14. The method of claim 12, further comprising receiving a Timing Advance Command in a Random Access Response message received in response to the RACH communication, wherein the first TA value is applied using the Timing Advance Command.

15. The method of claim 12, wherein the Timing Advance Command further includes a Timing Advance Command Medium Access Control (MAC) control element.

16. The method of claim 13, wherein the first UL CC set includes at least one uplink carrier with a dedicated physical uplink control channel (PUCCH) configuration, and the method further comprises ceasing transmitting on a resource corresponding to the PUCCH upon an expiration of the TAT.

17. The method of claim 13, wherein the first UL CC set includes at least one uplink carrier with at least one of a dedicated physical uplink control channel (PUCCH) configuration or a sounding and reference signal (SRS) configuration, and the method further comprises removing at least a part of either the PUCCH configuration or the SRS configuration upon an expiration of the TAT.

18. The method of claim 13, wherein the method further comprises removing one or more Hybrid Automatic Repeat Request (HARQ) buffers corresponding to the first UL CC set upon an expiration of the TAT.

19. The method of claim 11, wherein the first reference carrier is a first downlink (DL) carrier, the first DL carrier being associated with the first UL CC set.

20. The method of claim 12, wherein the initiating the RACH communication on the at least one of the identified one or more uplink carriers of the first UL CC set includes initiating a contention free based RACH procedure.