Performance of coherent square MQAM with Lth order diversity in Rician fading environment

This paper deals with the theoretical symbol error rate (SER) analysis of coherent square M-ary quadrature amplitude modulation (MQAM) with L^th order diversity in frequency non-selective slow Rician fading environment corrupted by additive white Gaussian noise (AWGN). The diversity combining technique considered here is maximal ratio combiner (MRC). A closed form expression for SER of MQAM in Rician fading environment under MRC diversity reception is derived and analyzed. The derived expression is in terms of a single finite integral with an integrand composed of elementary (trigonometric and exponential) functions. Because of its simple form, this expression readily allow numerical computation for cases of practical interests. To examine the dependence of error rate performance of MQAM on Rician parameter K and number of diversity branches L the numerical results are plotted as average SER versus average signal to noise ratio (SNR) for various values of K and L. The solution presented is general enough so that it includes Rayleigh fading and non-fading as special cases. The results presented in this paper are expected to provide useful information for exploiting the use of diversity for improving the performance of radio systems over fading channels.