Sum-Rate Maximizing Beamforming in Multicell Systems with Limited Feedback


Ramya Bhagavatula and Robert W. Heath, Jr.


to appear in IEEE Asilomar Conference on Signals, Systems & Computers, 2009.


We propose a beamforming algorithm to maximize the sum-rate of a two-cell two-user system, where multi-antenna base stations cooperate by sharing users’ channel state information (CSI) among themselves and beamform individually to their respective single-antenna users. We show that when full CSI is available at the base stations, the sum-rates obtained using the proposed strategy are very close to those obtained using multicell dirty paper coding. We then consider the limited feedback scenario where we evaluate the loss in sum-rate caused by quantizing CSI using random vector quantization. A feedback bit allocation strategy is proposed to partition the available feedback bits between the desired and interfering channels to minimize the loss in sum-rate. Finally, simulations are used to validate the results presented in the paper.

This paper is available here.