On the performance evaluation, selection, and design ofunique-words for time-division multiple access systems

The issues of performance evaluation, selection, and design of unique-words for time-division multiple-access systems are addressed for both additive white Gaussian noise and time-varying multipath fading channels. An efficient algorithm is proposed to compute the probability of a missed detection, which serves as the performance index of unique-words. Also, a simple upper bound on the probability of a missed detection is derived. This bound has been shown very tight for a large range of bit error rate. Based on this tight upper bound, a two-step algorithm is proposed for easy selection and design of good unique-words. For time-varying multipath fading channels, the performance of unique-words is evaluated for Rayleigh and Rician fading characteristics, which are suitable models for mobile and personal communication environments. The results show that the degradation caused by the fading effect can be larger than 10 dB for the performance of practical interest