Progressive image transmission by hybrid ARQ with code combining

We present an optimization algorithm for the type-II hybrid automatic repeat request (HARQ) scheme for progressive image transmission in channels with feedback information. A general finite state Markov chain (FSMC) channel model is used to approximate the slow fading phenomenon encountered in the feedforward channels for wireless communications. It is shown that the code combining technique further improves the performance of type-I HARQ schemes by about 0.3 dB under the same channel conditions.