The growing demand for wireless services has created the need for improving the spectral efficiency of wireless communications over fading channels.M-ary multilevel quadrature amplitude modulation(MQAM) in conjunction with transmit antenna selection combined with receive maximum-ratio combining is investigated in this paper.Based on alternative representations of Q(x)

the average symbol error rate of this combined spatial diversity scheme over flat Rayleigh fading channels is derived

and the effects of the time-varying nature of the wireless channels on its performance are analyzed.Numerical results show that the scheme can achieve significant diversity gain over traditional receive diversity schemes by distributing the antennas over transmit and receive side.