An importance sampling technique for a symbol-by-symbol TCM decoding/equalization algorithm

An importance sampling simulation technique is used to estimate the bit-error rate (BER) of a symbol-by-symbol trelliscoded modulation (TCM) decoder/equalizer proposed for digital microwave radio applications. To evaluate the performance at a BER smaller than 10 , we investigate a randomized bias technique previously developed by the authors. To properly select the bias vectors, the asymptotic (infinite signal-to-noise ratio) decision boundary is first determined. The simulation technique is then extended to the one-shot symbol-by-symbol TCM decoding/equalization algorithm which is equivalent to the recursive symbol-bysymbol detection algorithm of Abend and Fritchman. By using this novel importance sampling technique, we can speed up the simulation and efficiently evaluate the BER performance of the TCM decoder/equalizer.