Selective retransmission of data
View Patent ↗During reception of a higher-layer packet, segmented into lower-layer frames, a receiver will appropriately determine if a lower-layer frame was correctly received. If a lower-layer frame is not correctly received, and the maximum number of NAKs have been sent, the lower-layer frame is categorized as aborted. Once a frame has been categorized as aborted, the receiver determines an RLP frame corresponding to the higher layer packet boundary, sets V(N) to a next missing link-layer frame after a higher-layer packet boundary and pushes frames up to V(N) to the higher layer.
1. A method in a receiver for effecting selective retransmission by a transmitter within a communication system wherein packets at a higher layer are segmented and transmitted via a link-layer protocol, the method comprising the steps of:
in the receiver,
determining in the receiver that a link-layer frame needs to be aborted;
determining a set of link-layer frames ( V (B)) having higher-layer packet boundaries;
setting V(N) to a next missing link-layer frame after a higher-layer packet boundary if V (B) is not an empty set, otherwise setting V(N) to V(R), wherein V(N) is a frame number of a next link-layer frame needed for sequential deliver of frames and V(R) is a frame number of a next new link-layer frame expected; and
pushing all frames with sequence numbers up to V(N) up to the higher layer.
2. The method of claim 1 wherein the step of determining that the link-layer frame needs to be aborted comprises the step of determining that an Radio Link Protocol (RLP) frame needs to be aborted, wherein the RLP frame comprises a segment from a higher-layer Point-to-Point Protocol (PPP) packet.
3. The method of claim 1 wherein the step of determining that the link-layer frame needs to be aborted comprises the step of determining that a Radio-Link Protocol (RLP) frame needs to be aborted.
4. The method of claim 1 wherein the step of determining a set of link-layer frames having higher-layer packet boundaries comprises the step of determining a set of link-layer frames having Point-to-Point Protocol (PPP) packet boundaries.
5. An apparatus comprising:
a receiver having a poorly received link-layer frame as an input, wherein the link-layer frame comprises a segment of a higher-layer data packet; and
logic circuitry determining that the poorly received link-layer frame should be aborted; determining a set of link-layer frames (V(B)) having higher-layer packet boundaries; setting V(N) to a next missing link-layer frame after a next higher-layer packet boundary if V (B) is not an empty set, otherwise setting V(N) to V(R), wherein V(N) is a frame number of a next link-layer frame needed for sequential deliver of frames and V(R) is a frame number of a next new link-layer frame expected; and pushing all frames with sequence numbers up to V(N) up to the higher layer.
6. The apparatus of claim 5 wherein the higher-layer data packet comprises a PPP packet.
7. The apparatus of claim 5 wherein the poorly received link-layer packet comprises a poorly-received RLP packet.