New Simple Approximations for Error Probability and Outage in Fading

A new class of approximations for the bit error rate (BER), the symbol error rate (SER), and the outage of wireless digital communication systems impaired by fading and noise is derived. As compared to conventional high signal-to-noise ratio (SNR) approximations [1], these new approximations are better by an order of magnitude in the high SNR regime and retain their accuracy for a wider range of SNRs. They require the first two terms of the Taylor expansion of the channel probability density function (PDF). The resulting approximations for two diversity combiners, multiple-antenna eigenmode transmission and several important modulation schemes are developed.