Pilot-Based CSI Feedback in TDD/MIMO Systems with Cochannel Interference

This paper proposes a pilot-based channel state information (CSI) feedback in time-division duplex (TDD) / multi-input multi-output (MIMO) system, which enables the transmitter to perform transmit beamforming considering the receiver's interference. In the proposed method, the receiver sends reverse-link pilot signals spatially prefiltered by linear precoder dependent on the receiver's interference characteristics. The transmitter exploits responses of the reverse-link pilot signals to perform transmit beamforming considering the receiver's interference. The transmitter also predicts the receiver's output signal-to-interference-plus-noise power ratio (SINR) for each data stream. From simulation results, it is found that the transmitter achieves efficient transmission performance maintaining small control errors based on the proposed CSI feedback.