Exact BER analysis of M-ary orthogonal signaling with MRC over Ricean fading channels

Orthogonal modulation is very attractive for power-limited wireless communication; thus, analysis of such signal formats in fading channels is of great theoretical and practical importance. The mathematical tractability of coherent M-ary orthogonal modulation performance over fading channels is quite restricted, especially when Ricean fading is considered. In a high-power regime, that is, one with high signal-to-noise ratios (SNRs), tight asymptotic approximations for the analysis of the bit-error rate (BER) can be employed [1]. However, limited results are found in the literature [2, 3] for cases when an exact error-rate formulation is applied to a low-power regime (moderate and low SNRs), with an arbitrary number of signals. Recently, in [3] the analysis of coherent M-ary orthogonal signaling over Ricean fading channels with maximal ratio combining (MRC) leads to BER expressions in the form of a single integral