Method For Detecting Radio Link Failure For Transmission Over Enhanced Dedicated Channel In A CELL_FACH State

• US 20140078892A1
• Filed: 12/28/2012
• Published: 03/20/2014
• Est. Priority Date: 10/29/2007
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Cave, Christopher, Kim, In H., Pelletier, Benoit, Marinier, Paul, Pani, Diana
• Granted Patent: US 9,749,877 B2
• Time in Patent Office: Days
• US Class Current: 370/228
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/305 Handover due to radio link failure control signalling for hand-off failure H04W36/0079
• CPC Class Codes: H04W 76/19 Connection re-establishment

Abstract

A method and apparatus are used for detecting a radio link (RL) failure and a post verification process. A quality of a downlink fractional dedicated physical channel (F-DPCH) is monitored once a transmission on an enhanced dedicated channel (E-DCH) has begun. It is determined whether the quality of the downlink F-DPCH is below a predefined threshold. If the quality is below the predefined threshold, then an occurrence of an RL failure is declared and a transmission over the E-DCH in a cell forward access channel (CELL_FACH) state is terminated. In a case of the post verification failure, E-DCH resources are released.

Claims

1. A method implemented in a wireless transmit receive unit (WTRU) for detecting a radio link (RL) failure in cell forward access channel (CELL_FACH) state, the method comprising:

estimating a quality of a downlink channel;

determining that a RL failure has occurred when the quality of the downlink channel is below a predefined threshold over a predetermined period of time; and

stopping a transmission procedure associated with an enhanced dedicated channel (E-DCH).

2. The method of claim 1, wherein the downlink channel comprises a fractional dedicated physical channel (F-DPCH).

3. The method of claim 1, wherein the downlink channel comprises a dedicated physical control channel (DPCCH).

4. The method as in claim 1, wherein the E-DCH comprises an E-DCH dedicated physical control channel (E-DPCCH).

5. The method as in claim 1, wherein the E-DCH comprises an E-DCH dedicated physical data channel (E-DPDCH).

6. The method as in claim 1, wherein further comprising releasing E-DCH resources.

7. The method as in claim 1, wherein further comprising resetting a medium access control (MAC) entity.

8. A method implemented in a wireless transmit receive unit (WTRU) for handling a radio link (RL) failure, the method comprising:

determining that a criterion for RL failure is met when operating in in cell forward access channel (CELL_FACH) state;

starting a timer; and

checking whether a cell reselection criterion is met while the timer is running.

9. The method of claim 8, further comprising:

upon determining that the criterion for RL failure is met, waiting a predefined amount of time prior to starting the timer.

10. The method of claim 8, further comprising:

determining that the cell reselection criterion is met;

stopping the timer; and

performing cell reselection.

11. The method of claim 8, wherein the timer stops when is cell reselection performed.

12. The method of claim 8, further comprising attempting a random access when the cell reselection criterion is not met upon expiry of the timer.

13. The method of claim 8 wherein the timer is a backoff timer.

14. A wireless transmit receive unit (WTRU), the WTRU comprising:

a processor configured to;

estimate a quality of a downlink channel when operating in in cell forward access channel (CELL_FACH) state;

determine that a RL failure has occurred when the quality of the downlink channel is below a predefined threshold over a predetermined period of time; and

stop a transmission procedure associated with an enhanced dedicated channel (E-DCH).

15. The WTRU of claim 14, wherein the downlink channel comprises a fractional dedicated physical channel (F-DPCH).

16. The WTRU of claim 14, wherein the downlink channel comprises an E-DCH physical control channel (DPCCH).

17. The WTRU of claim 14, wherein the E-DCH comprises an E-DCH dedicated physical control channel (E-DPCCH).

18. The WTRU of claim 14, wherein the E-DCH comprises an E-DCH dedicated physical data channel (E-DPDCH).

19. The WTRU of claim 14, wherein further comprising releasing E-DCH resources.

20. The WTRU of claim 14, wherein further comprising resetting a medium access control (MAC) entity.

21. A wireless transmit receive unit (WTRU), the WTRU comprising:

a processor configured to;

determine that a criterion for radio link (RL) failure is met when operating in in cell forward access channel (CELL_FACH) state;

start a timer; and

check whether a cell reselection criterion is met while the timer is running.

22. The WTRU of claim 21, wherein the processor is further configured to wait a predefined amount of time upon determining that the criterion for RL failure is met prior to starting the timer.

23. The WTRU of claim 21, wherein the processor is further configured to:

determine that the cell reselection criterion is met;

stop the timer; and

perform cell reselection.

24. The WTRU of claim 21, wherein the timer stops when is cell reselection performed.

25. The WTRU of claim 21, wherein the processor is further configured to attempt a random access when the cell reselection criterion is not met upon expiry of the timer.

26. The WTRU of claim 21, wherein the timer is a backoff timer.