Multiple input multiple output (MIMO) precoding is an efficient scheme that may significantly enhance the communication link. However, this enhancement comes with a cost. Many precoding schemes require channel knowledge at the transmitter that is obtained through feedback from the receiver. Focusing on the natural common fusion of orthogonal frequency division multiplexing (OFDM) and MIMO, we exploit the channel correlation in the frequency and spatial domain to reduce the required feedback rate in a frequency division duplex (FDD) system. The proposed feedback method is based on Huffman coding and is employed here for the single stream case. The method leads to a significant reduction in the required feedback rate, without any loss in performance. The proposed method may be extended to the multi-stream case.
@article{arxiv.0907.4521,
title = {Grassmannian Beamforming for MIMO-OFDM Systems with Frequency and Spatially Correlated Channels Using Huffman Coding},
author = {Igor Gutman and Doron Ezri and Dov Wulich},
journal= {arXiv preprint arXiv:0907.4521},
year = {2009}
}