Adaptive coded modulation for wireless packet data systems

Selection of modes, i.e. coding and modulation schemes against the current channel is a way to increase the degree of service to individual users as well as improving system capacity in a wireless packet data system. By proper selection of trellis coded modulation schemes, all modes can use a common receiver structure without sacrificing error performance. Apart from a low receiver complexity, this also enables code combining of different modes, which is useful when ARQ is used. Through system level simulations on correlated Rayleigh fading channels it is found that a simple way of selecting the proper mode gives excellent performance.