Multi-cell hybrid channel information feedback for downlink multi-cell precoding

A multi-cell hybrid channel state information (CSI) feedback scheme was proposed, which has an ideal nested hierarchical structure to support not only the advanced multi-cell MIMO precoding, but also the traditional single-cell single-user and multi-user precoding transmissions. A quantization scheme for the multi-cell hybrid CSI feedback was provided, using codebook based vector-quantization for the per-cell CSI information part and scalar-quantization for the inter-cell CSI information part. The hierarchical structure of the multi-cell hybrid CSI feedback simplifies greatly the feedback signaling design, and implicitly supports the dynamic switch between different operation modes. Simulation results show that the proposed CSI feedback solution can enable efficient DL single-cell and multi-cell precoding transmissions.