An Efficient Stop-and-Wait Type II Hybrid ARQScheme

In this paper, an efficient Stop-and-Wait ARQ protocol proposed by Sastry is modified to include a parity retransmission type II hybrid AR Q scheme. Unlike Sastry's scheme in which simple repeats of a data packet are transmitted, with the type II hybrid ARQ scheme, the data packet to be transmitted is encoded with a rate 1/2 code, and repetitions alternate between the two sequences obtained at the output of the encoder. At the receiver end, the received sequences are combined and decoding for error correction is performed on the combined sequence. The performances of this type II hybrid ARQ scheme, and · the basic Sastry's Scheme are compared for three different channel models: a binary symmetric channel (BSC), a non-fading and a Rayleighfading additive white Gaussian noise channel. In all cases, it is found that the throughput can be substantially increased. 1 This research was supported by the Natural Sciences and Engineering Research Council of Canada. 1