Discrete channel models for wireless data services

The evaluation of error control strategies for different wireless services implies the existence of models which can describe physical and data-link layers ps a whole. In this paper a method of modelling of discrete channels (DC) is presented. This method is based on nested hidden Markov models and takes into consideration hard and soft decision outputs. It is shown that realistic DC models built for GSM radio channels (at bit level as well as at TDMA frame level) may have relatively big number of channel states. DC model parameters for ARQ and hybrid FEC-ARQ schemes are presented.