ADAPTIVE ERROR CONTROL FOR SLOWLY VARYING CHANNELS

This paper presents an adaptive error control technique based on the u se of type-I hybrid-ARQ protocols. The communication channel is assume d to be slowly varying and is modeled using a finite state Markov chai n. The system counts the number of retransmission requests during an o bservation interval called a frame and, together with knowledge of the error control strategy in use and a set of thresholds, estimates the state of the channel. The coding strategy which maximizes throughput w hile maintaining a minimum required level of reliability is chosen for use in the next frame. Examples are provided showing system design an d performance using families of Reed-Solomon codes.