MARKOV MODELS FOR LIMITED FEEDBACK MIMO SYSTEMS
The Proc. of IEEE Intl. Conf. on Acoustics, Speech and Signal, vol. 4, pp. IV-9-IV-12, Toulouse, France, May 14-19, 2006.
Multiple antenna wireless systems with feedback of quantized channel information, called “limited feedback” systems, are an attractive choice for improving the quality of downlink transmission. Most works in this area use the block-fading channel model where the channel is assumed constant in each block and different blocks uncorrelated. In this paper, we consider limited feedback in a time-correlated channel. Markov models are introduced for analyzing the effect of Doppler frequency on limited feedback rate in a MIMO system with channel gain feedback or beamformer feedback. Numerical results show that the feedback frequency (and hence the rate) is proportional to the Doppler frequency.