通过MATLAB软件；通过仿真得出性能曲线；从而比较bpsk的性能-The bit-error rate (BER) of binary phase-shift keying in Rayleigh fading, using the Alamouti transmission scheme and receiver selection diversity in the presence of channel-estimation error, is studied. Closed-

duction techniques proposed in the art are expressed as a spectral gain depending on the a priori SNR. In the well-known decision- directed approach, the a priori SNR depends on the speech spec- trum estimation in the previous frame. As a conse

when SNR is high , 1st sample estimator provides good estimate of A. it has no ise effect . so we don’t need averaging effect to reduce noise when SNR is high. However variance is still low in sample mean estimator which shows that in reality ,samp