LIMITED FEEDBACK WITH JOINT CSI QUANTIZATION FOR MULTICELL COOPERATIVE GENERALIZED EIGENVECTOR BEAMFORMING

Existing work on limited feedback for cooperative multicell beamforming quantizes the desired and interfering channel state information (CSI) using separate codebooks. In this paper, it is shown that comparatively higher sum-rates can be obtained by jointly quantizing the desired and interfering CSI using a single codebook. A selection criterion is developed for random vector quantization (RVQ) to show that joint quantization with RVQ yields higher sum-rates than those obtained using separate codebooks. The generalized Lloyd algorithm is then used to generate codebooks using the code-word design strategy proposed in this paper. Simulations are used to show that the proposed joint quantization approaches perform almost as well as the full CSI case.