Equal Gain Beamforming in Rayleigh Fading Channels

Precoding techniques with limited feedback information can achieve satisfactory performance while the amount of feedback information is kept small. In this paper, we analyze the theoretical performance of equal gain precoder and find that its performance is at most 1.049 dB worse than the optimal precoder no matter how the number of transmit antennas increases. Moreover, we found that the equal gain precoder in general can achieve comparable performance with the Grassmannian precoder in the same moderate feedback bits. Hence, it has several advantages compared with the Grassmannian precoder that we will explain later in the paper.