Low-Rate Predictive Feedback for the OFDM MIMO Broadcast Channel

For a frequency division duplexing (FDD) cellular system, the downlink channel state information (CSI) has to be fed back by mobile terminals (MTs) in order to perform beamforming and scheduling at base station (BS). In this paper, for an orthogonal frequency division multiplexing (OFDM) modulation format, we propose a novel CSI feedback strategy based on the prediction of channel variations. Indeed, quantization of CSI and feedback signalling are jointly designed in order to obtain a low rate feedback signal. Also, an user selection method is devised to allocate users across the subcarriers. Simulations for a 3G long term evolution scenario show a significant performance improvement achieved by the predictive strategy with respect to existing techniques.