A general approach to performance evaluation of higher order coded modulation systems on fading channels

This paper outlines an efficient approach to evaluate the performance of higher order coded modulated systems. Most of the approaches suggested so far have evaluated the probability of individual pairwise error events and obtained the union bound from the bit error probability. This gives a very tight bound on the performance of SNR´s above cutoff rate for BPSK modulation. However, for higher order modulation systems, the number of bit errors in a symbol slot depends on the exact two modulated symbols involved in an error event. Due to computational complexity, the performance is usually approximated by a few dominant error events. The bounds thus obtained are only good for very high SNR´s and AWGN channel. On the other hand, for a fading channel the correlation structure of the channel introduces another element of complexity. In this paper, we develop a general approach which assumes an ideal model for the modulator and enables us to extend the linearity of the considered codes to simplify the computation of the performance bounds for fading channels. This approach also gives a greater insight into the influence of modulator parameters on the performance of coded modulation systems. The application of our analytical model is demonstrated with examples and simulations.