Progressive refinement for high resolution limited feedback multiuser MIMO beamforming

Limited feedback enables the practical use of channel state information in single user and multiple user MIMO (multiple input multiple output) wireless communication systems. Using the limited feedback concept, channel state information at the receiver is quantized by choosing a representative element from a codebook known to both the receiver and transmitter. Unfortunately, achieving the high resolution required by multiuser MIMO communication is challenging due to the large size codebooks required. This paper proposes a progressive refinement concept that uses a base codebook quantization followed by a progressively scaled local codebook to enable high resolution quantization and reconstruction.