Transmit Beamforming with Reduced Channel State Information in MIMO-OFDM Wireless Systems

The use of multiple antennas for diversity and array gain may require accurate channel state information (CSI) on each subcarrier in orthogonal frequency division multiplexing systems. Such CSI is usually reported from the receiver to the transmitter, causing a significant amount of feedback signaling burden. Recent work can noticeably reduce the feedback signaling burden by exploiting the channel correlation properties in the frequency domain, but it can be applied to the generation of a single beam [1]. In this paper, this idea is extended to the use of multiple beams for spatial multiplexing. Simulation results show that the proposed scheme can improve the performance using the same amount of feedback signaling burden or provide the same performance while noticeably reducing the amount of feedback signaling burden, compared to conventional schemes. Keywords-codebook; feedback; MIMO; OFDM system; precoding;