Transmission diversity with limited feedback information in fading channels

Two schemes of spatial transmission diversity with linear combination are devised for BPSK wireless communication on slowly Rayleigh fading channels in which there is a limit on the number of bits for sending the feedback information in the reverse channel. In the first scheme (Scheme I), only one bit is sent back for each antenna element to give the feedback information, while in the second scheme (Scheme II), two bits are used for each element to characterize the feedback information. In Scheme II, under the constraint of extra transmission power, the determination of combination weights becomes the problem of power allocation to the array elements. Suboptimal and optimal methods are proposed to determine the combination weights of Scheme II. Numerical results are illustrated for different cases to examine the performance of the average bit error rate (BER)