A New Generalized Closed Form Expression for Average Bit Error   Probability Over Rayleigh Fading Channel
  Except for a few simple digital modulation techniques, derivation of average bit error probability over fading channels is difficult and is an involved process. In this letter, curve fitting technique has been employed to express bit error probability over AWGN of any digital modulation scheme in terms of a simple Gaussian function. Using this Gaussian function, a generalized closed form expression for computing average probability of bit error over Rayleigh fading channels has been derived. Excellent agreement has been found between error probabilities computed with our method and the rigorously calculated error probabilities of several digital modulation schemes. 
Sanjay Singh, M. Sathish Kumar and H.S. Mruthyunjaya
cs.IT math.IT