WLC38-1: Transmit Beamforming with Finite-Rate Feedback for Frequency-Selective Channels

In this paper, we consider beamforming with finite-rate feedback for frequency-selective channels with decision-feedback equalization (DFE) at the receiver. Using average bit error rate as performance measure, we propose a global vector quantization (GVQ) algorithm for codebook design. This algorithm is deterministic and independent of initial conditions. The proposed design method does not impose any constraints on the number of transmit and receive antennas, the antenna correlation, or the fading statistics. Simulation results for typical GSM/EDGE channels show that finite-rate feedback beamforming with one or two feedback bits achieves significant performance gains over single-antenna transmission, transmit antenna selection, and optimized delay diversity. While beamforming filters of length one are preferable if only few feedback bits can be afforded, longer filters can improve performance if a sufficiently large number of feedback bits is available.