On distributed antenna systems with limited feedback precoding: Opportunities and challenges

The distributed antenna system is a promising technique to enhance system performance in next-generation broadband wireless mobile communications. The application of linear precoding with space time codeword based on channel state information can further enhance the link quality and reduce the receiver complexity in DASs. However, designing the optimal codebook for DAS to convey the precoding information remains an open issue. This article provides a tutorial addressing various issues of DASs with limited feedback, focusing on the challenges in its codebook design. A suboptimal codebook design is then proposed, suitable for DAS. Furthermore, an effective feedback reduction strategy without performance loss is presented by exploiting the channel correlation property. Numerical results are given to demonstrate the effectiveness of the proposed scheme.