Efficient Evaluation of BER for Arbitrary Modulation and Signaling in Fading Channels

We present a numerically efficient method to evaluate uncoded bit-error rate for arbitrary two-dimensional constellation and nonuniform signaling in fading channels. Compared to the bounding techniques, treating the problem at the same level of generality, the proposed method is shown to be more accurate (by construction) and numerically more efficient: for moderate constellation size, the complexity reduction may reach two orders of magnitude. The operation of the proposed method is illustrated with numerical examples obtained in Nakagami-m fading.