An adaptive hybrid ARQ scheme for slowly time-varying communication channels

An adaptive hybrid ARQ scheme for slowly time-varying communication channels that aims to maximize the average throughput under a given reliability constraint is presented. A hidden Markov model is used as the channel model. Punctured convolutional codes and the Viterbi algorithm with the Yamamoto-Itoh retransmission protocol are employed for encoding and decoding, respectively. A Shewhart type procedure is developed to detect changes in the channel state.