Delay analysis of the selective-repeat ARQ with the per flow resequencing

An SR (selective-repeat) ARQ (automatic repeat request) protocol is used for effective packet error recovery on a satellite channel. This SR ARQ has a problem of large delay due to the resequencing of received packets. To mitigate this problem, the PFRS (per flow resequencing) scheme was proposed, where resequencing is performed independently for each upper layer flow, while the detection of lost packets and associated retransmissions are performed based on the whole flows multiplexed over the SR ARQ. The paper models the SR ARQ protocol, where the maximum number of retransmissions is limited, by a collection of simple stop-and-wait protocols; it shows calculation results on the delay distribution of retransmission and resequencing and proves the effectiveness of the PFRS scheme.