RLP retransmission for CDMA communication systems
Techniques for retransmitting data via RLP in a CDMA (e.g., cdma2000) system with a first retransmission mechanism provided by the RLP and a second retransmission mechanism provided by an HARQ-CF. In one method, missing RLP frames are first detected (e.g., by a receiver RLP). A dynamic timer is then maintained (e.g., by a receiver HARQ-CF) for each RLP frame detected to be missing. The dynamic timers are event-driven and have variable time durations. Each dynamic timer is updated based on events known to the receiver HARQ-CF. Fixed timers with fixed time durations may also be maintained (e.g., by the receiver RLP) for the missing RLP frames. Whether or not a missing RLP frame is lost is determined based on the dynamic timer and the fixed timer (if any) maintained for the RLP frame. A NAK may be issued for retransmission of each RLP frame deemed to be lost.
1. In a wireless communication system with a first retransmission mechanism in a first sublayer and a second retransmission mechanism in a second sublayer, a method for retransmitting data with the first retransmission mechanism, comprising:
detecting missing frames in the first sublayer;
initiating a dynamic timers for each missing frames in the first sublayer, the dynamic timer for each missing frame associated with a respective candidate set of logical channels that may be used to transmit the missing frame;
removing, from the set of logical channels, logical channels identified as conveying, at the second sublayer, packets associated with frames successfully received at the first sublayer:
updating the dynamic timers based on a determination that the candidate set is empty; and
determining whether or not the frames detected to be missing are lost based on the one or more dynamic timers.
2. The method of claim 1 , wherein a logical channel is also removed from a candidate set if a new packet in the second layer is transmitted via the logical channel.
3. The method of claim 1 , wherein a logical channel is also removed from a candidate set if no transmission is received via the logical channel within a particular time period.
4. In a CDMA communication system with a first retransmission mechanism provided by a Radio Link Protocol (RLP) and a second retransmission mechanism provided by a hybrid automatic retransmission control function (HARQ-CF), a method for retransmitting data via the RLP, comprising:
detecting missing RLP frames;
initiating a dynamic timer for each RLP frame, each dynamic timer associated with a respective candidate set of ARQ channels that may be used to transmit the missing RLP frame;
removing, from the set of ARQ channels, ARQ channels identified as conveying, at the HARQ-CF sublayer, HARQ packets associated with successfully received RLP frames;
updating each dynamic timer based on a determination that the representative candidate set is empty; and
determining whether or not each RLP frame detected to be missing is lost based on the dynamic timer maintained for the RLP frame.
5. The method of claim 4 , wherein an ARQ channel is removed from a candidate set if a new HARQ packet is transmitted via the ARQ channel.
6. The method of claim 4 , wherein an ARQ channel is also removed from a candidate set if no transmission is received via the ARQ channel within a particular time period.
7. The method of claim 6 , wherein the particular time period is selected based on likelihood of receiving a transmission on a given ARQ channel.
8. A method for detecting lost frames in a communication system having a first retransmission mechanism in a first sublayer and a second retransmission mechanism in a second sublayer, the method comprising:
initiating a dynamic timer for a missing frame detected as missing at a first sublayer, the dynamic timer associated with a candidate set of logical channels that may be used to transmit the missing frame;
removing, from the candidate set of logical channels, logical channels through which packets associated with successfully received frames at the first sublayer have been received at a second sublayer;
updating the dynamic timer when the candidate set is empty; and
determining the missing frame is a lost frame based on the dynamic timer.
9. A method in accordance with claim 8 , wherein the updating the dynamic timer comprises setting the dynamic timer to expire.
10. A method in accordance with claim 8 , wherein the first sublayer is in accordance with a Radio Link Protocol (RLP) and the second sublayer is in accordance with a hybrid automatic retransmission control function (HARQ-CF) residing under the RLP.
11. A method in accordance with claim 8 , wherein the determining the missing frame is a lost frame comprises determining the missing frame is a lost frame when the dynamic timer expires.
12. A method in accordance with claim 8 , further comprising:
requesting a retransmission of the lost frame in the first sublayer using the first retransmission mechanism.
13. A method in accordance with claim 8 , wherein the removing comprises removing logical channels through which no packet has been transmitted within a time period.
14. A method in accordance with claim 8 , further comprising:
initiating each of a plurality of dynamic timers for each of a plurality of missing frames.
15. A method in accordance with claim 8 , further comprising:
canceling the dynamic timer when the missing frame is received.
16. A processor for detecting lost frames in a communication system having a first retransmission mechanism in a first sublayer and a second retransmission mechanism in a second sublayer, the processor configured execute the steps of:
initiating a dynamic timer for a missing frame detected as missing at a first sublayer, the dynamic timer associated with a candidate set of logical channels that may be used to transmit the missing frame;
removing, from the candidate set of logical channels, logical channels through which packets associated with successfully received frames at the first sublayer have been received at a second sublayer;
updating the dynamic timer when the candidate set is empty; and
determining the missing frame is a lost frame based on the dynamic timer.
17. A processor in accordance with claim 16 , wherein the updating the dynamic timer comprises setting the dynamic timer to expire.
18. A processor in accordance with claim 16 , wherein the first sublayer is in accordance with a Radio Link Protocol (RLP) and the second sublayer is in accordance with a hybrid automatic retransmission control function (HARQ-CF) residing under the RLP.
19. A processor in accordance with claim 16 , wherein the determining the missing frame is a lost frame comprises determining the missing frame is a lost frame when the dynamic timer expires.
20. A processor in accordance with claim 19 , the processor further configured to execute the step of:
requesting a retransmission of the lost frame in the first sublayer using the first retransmission mechanism.
21. A processor in accordance with claim 16 , wherein the removing comprises removing logical channels through which no packet has been transmitted within a time period.
22. A processor in accordance with claim 16 , the processor further configured to execute the step of:
initiating each of a plurality of dynamic timers for each of a plurality of missing frames.
23. A processor in accordance with claim 16 , the processor further configured to execute the step of:
canceling the dynamic timer when the missing frame is received.
24. A receiver in a wireless communication system with a first retransmission mechanism in a first sublayer and a second retransmission mechanism in a second sublayer, the receiver comprising:
a RX data processor operative to process a data transmission to provided decoded data; and
a controller operative to:
initiate a dynamic timer for a missing frame detected as missing at a first sublayer, the dynamic timer associated with a candidate set of logical channels that may be used to transmit the missing frame;
remove, from the candidate set of logical channels, logical channels through which packets associated with successfully received frames at the first sublayer have been received at a second sublayer;
update the dynamic timer when the candidate set is empty; and
determine the missing frame is a lost frame based on the dynamic timer.
25. A receiver in accordance with claim 24 , the controller operative to update the dynamic timer by setting the dynamic timer to expire.
26. A receiver in accordance with claim 24 , wherein the first sublayer is in accordance with a Radio Link Protocol (RLP) and the second sublayer is in accordance with a hybrid automatic retransmission control function (HARQ-CF) residing under the RLP.
27. A receiver in accordance with claim 24 , wherein the controller is further operative to determine the missing frame is a lost frame by determining the missing frame is a lost frame when the dynamic timer expires.
28. A receiver in accordance with claim 27 , the controller further operative to:
request a retransmission of the lost frame in the first sublayer using the first retransmission mechanism.
29. A receiver in accordance with claim 24 , wherein the controller is operative to remove, from the candidate set, logical channels through which no packet has been transmitted within a time period.
30. A receiver in accordance with claim 24 , wherein the controller is operative to initiate each of a plurality of dynamic timers for each of a plurality of missing frames.
31. A receiver in accordance with claim 24 , wherein the controller is operative to cancel the dynamic timer when the missing frame is received.