Analysis and comparison of different feedback schemes for coordinated cellular networks

This paper compares several feedback schemes of a limited feedback system in a coordinated cellular networks. In a coordinated system one user can be served by different base stations (BSs) simultaneously. Conventional codebook is intended for single BS, its aim is to maximize the amplitude of the receive signal. When multiple BSs are equipped, phase discrimination among different BSs at the receive side may lead to performance degradation. Brute-force search through the entire BSs is a heavy burden especially when the BS number is large. In order to mitigate the negative effects, we present one solution dedicated to the coordinated system in this paper. When the BS number is small, we put forward a codebook design scheme based on the Lloyd codebook. When the BS number is large, we propose phase criterion instead of amplitude criterion in choosing the beamforming vector. Both schemes work well under their operating region. With our solution we can effectively reduce performance degradation in a coordinated cellular networks while still maintain a low complexity burden. Simulation results verify the effectiveness of our proposed schemes.