Beamforming in Wireless Relay-Interference Networks with Quantized Feedback

This paper is on quantized beamforming in wireless amplify-and-forward relay interference networks with multiple transmitter-receiver pairs. We design the quantizer of the feedback information specifically to optimize the union bound on the bit error rate performance. Two different quantization schemes are considered. First, using a global quantizer structure, we analytically show that a simple feedback scheme based on relay selection can achieve full diversity. Then, we design a local quantization scheme with distributed quantizer encoders, one at each receiver. We show that, with only a few feedback bits, high diversity gains can be obtained with the local quantizer structure as well. Simulations are also provided, confirming our analytical results. We observe that our designs guarantee an equal high diversity gain for each transmitter-receiver pair.