Quantizer Design for Codebook-Based Beamforming in Temporally-Correlated Channels

Codebook-based transmit beamforming with receive combining is a simple and efficient strategy for multiple- input multiple-output (MIMO) wireless systems. However, as a closed-loop technique, codebook-based transmit beamforming suffers from the performance degradation due to feedback delay. In this paper, we design quantizers robust to the feedback delay for codebook-based beamforming systems. Aiming at maximizing the average receive signal-to-noise ratio (SNR) or minimizing the average bit error rate (BER), optimal codeword selection rules are derived for the quantizer. Numerical results reveal that the proposed quantizers well compensate the performance loss due to feedback delay.