The effect of feedback quantization on the throughput of a multiuser diversity scheme

The impact of the quantization of SNR measurements on the throughput of a multiuser diversity scheme for constant-rate transmission is investigated under a block-Rayleigh fading assumption. In the downlink, each user measures its SNR, quantizes it, and feeds it back to the transmitter, which transmits a packet to the user with the highest quantized SNR. In the case of several users having the same quantized SNR, one of them is selected at random. It is concluded that using only a few quantization levels can yield a throughput that is only slightly less than the throughput obtained by using unquantized feedback.