P/sub epsilon /-derived S/N ratio: a novel ideal error probability performance reference for fading channels

Error probability (P/sub epsilon /)-signal to noise ratio (S/N) curves for an ideal modem receiver over an additive white Gaussian noise channel are not useful with time-varying channels, because channels with the same average S/N can have widely differing error probabilities. From consideration of how an actual optimised system would perform over a time-varying channel, a more realistic P/sub epsilon / reference is derived. This leads to a new S/N measure that is a better indicator of channel quality. Application of the reference is demonstrated by evaluation of the performance of a RLS lattice DFE HF modem receiver.<>