On the channel statistics in Hybrid ARQ systems for correlated channels

This paper discusses a result for error control techniques based on retransmissions, most notably hybrid automatic repeat request schemes. We assume that the underlying coding technique is described by the so-called reliable region. Under this assumption, we derive the channel distribution after a frame is either acknowledged or discarded. This is derived within an entirely analytical framework, where we show that such a distribution can be found as the result of an iterative process. Remarkably, this distribution is not the same as the steady-state channel distribution, and can be significantly different from it. Thus, using one instead of the other can lead to evaluation errors, which instead are avoided by our model.