Method and apparatus for supporting uplink starvation avoidance in a long term evolution system

1. A method for implemented in a wireless transmit/receive unit (WTRU), the method comprising:

maintaining, at the WTRU, maximum sizes of token buckets for respective radio bearers (RBs);

maintaining, at the WTRU, current sizes of the token buckets, wherein the current sizes are based on respective token accumulation patterns, wherein token accumulations in the respective token buckets are based on the respective current sizes and maximum sizes, and wherein the current and maximum sizes of each token bucket are based on a prioritized bit rate (PBR);

determining current buffer status information, wherein the current buffer status information includes (i) the current sizes for the token buckets and (ii) buffer levels associated with the RBs, wherein the buffer levels are indicative of respective amounts of uplink (UL) data for transmission via the RBs;

transmitting a buffer status report (BSR) responsive to an event, wherein the event comprises one or more buffer levels exceeding or falling below respective thresholds, and wherein the BSR comprises the one or more buffer levels;

determining that a transmission of a packet of the UL data for transmission via one of the RBs results in the corresponding token bucket of the one RB being a negative token bucket; and

transmitting the packet of the UL data via the one RB.

2. The method of claim 1 , further comprising: receiving a grant for handling the reported buffer levels.

3. The method of claim 1 , wherein determining that a transmission of a packet of the UL data for transmission via one of the RBs results in the corresponding token bucket of the one RB being a negative token bucket comprises: determining, at the WTRU, the corresponding token bucket of the one RB lacks a sufficient amount of tokens to transmit the packet of the UL data.

4. The method of claim 1 , wherein each of the current sizes of the token buckets maintained at the WTRU can be a negative value responsive to scheduling or transmission of a packet of the uplink data via the corresponding RB.

5. The method of claim 1 , further comprising: scheduling the packet of the UL data for transmission via the one RB.

6. The method of claim 5 , wherein scheduling the packet of the UL data for transmission via the one RB results in the corresponding token bucket of the one RB being a negative token bucket.

7. The method of claim 1 , wherein each of the current sizes of the token buckets maintained at the WTRU can be a negative value responsive to scheduling or transmission of a packet of the uplink data via the corresponding RB.

8. The method of claim 1 , further comprising: receiving, at the WTRU, signaling including information for configuring the maximum sizes of the token buckets.

9. The method of claim 1 , wherein the BSR is transmitted for less than all of the RBs.

10. The method of claim 1 , wherein the BSR is transmitted for a group of the RBs.

11. The method of claim 1 , wherein the RBs comprise: a high-priority RB and a non-high-priority RB.

12. The method of claim 11 , wherein the respective thresholds comprise: a threshold for the buffer level of the high-priority RB and a threshold for the buffer level of the non-high-priority RB.

13. The method of claim 11 , wherein the one or more buffer levels exceeding or falling below respective thresholds comprise: a buffer level associated with the high-priority RB, and a buffer level associated with the non-high-priority RB.

14. The method of claim 12 , wherein the respective thresholds comprise: a threshold for the buffer level of the high-priority RB and a threshold for the buffer level of the non-high-priority RB, and wherein the event comprises: the buffer level associated with the high-priority RB exceeding or falling below threshold for the buffer level of the high-priority RB, and wherein buffer level associated with the non-high-priority RB exceeding or falling below threshold for the buffer level of the non-high-priority RB.

15. The method of claim 1 , wherein the thresholds are based on maximum sizes of the token buckets.

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

a receiver;

a transmitter; and

a processor in communication with the receiver and the transmitter, wherein the processor is configured to:

maintain, at the WTRU, maximum sizes of token buckets for respective radio bearers (RBs);

maintain, at the WTRU, current sizes of the token buckets, wherein the current sizes are based on respective token accumulation patterns, wherein token accumulations in the respective token buckets are based on the respective current sizes and maximum sizes, and wherein the current and maximum sizes of each token bucket are based on a prioritized bit rate (PBR);

determine current buffer status information, wherein the current buffer status information includes (i) the current sizes for the token buckets and (ii) buffer levels associated with the RBs wherein the buffer levels are indicative of respect amounts of uplink (UL) data for transmission via the RBs;

provide a buffer status report (BSR) responsive to an event, wherein the event comprises one or more buffer levels exceeding or falling below respective thresholds, and wherein the BSR comprises the one or more buffer;

determine that a transmission of a packet of the UL data for transmission via one of the RBs results in the corresponding token bucket of the one RB being a negative token bucket; and

wherein the processor is configured to: transmit the packet of the UL data via the one RB.

17. The WTRU of claim 16 , wherein the processor is configured to receive a grant for handling the reported buffer levels.

18. The WTRU of claim 16 , wherein the processor being configured to determine that a transmission of a packet of the UL data for transmission via one of the RBs results in the corresponding token bucket of the one RB being a negative token bucket comprises: the processor being configured to determine the corresponding token bucket of the one RB lacks a sufficient amount of tokens to transmit the packet of the UL data.

19. The WTRU of claim 16 , wherein each of the current sizes of the token buckets maintained at the WTRU can be a negative value responsive to a scheduling or a transmission of a packet of the uplink data via the corresponding RB.

20. The WTRU of claim 16 , wherein the processor is configured to receive signaling including information for configuring the maximum sizes of the token buckets.

21. The WTRU of claim 16 , wherein the processor is configured to provide the BSR for less than all of the RBs.

22. The WTRU of claim 16 , wherein the processor is configured to:

schedule transmission of the packet of the UL data via the one RB.

23. The WTRU of claim 11 , wherein each of the current sizes of the token buckets maintained at the WTRU can be a negative value responsive to scheduling or transmission of a packet of the uplink data via the corresponding RB.