Pilot-Based Channel State Feedback in TDD/MIMO Systems with Co-channel Interference

This paper proposes a pilot-based channel state information (CSI) feedback from a terminal to a base station (BS), considering the terminal's co-channel interference in a time-division duplex/multi-input multi-output system. In the proposed method, the terminal determines a precoding matrix according to the terminal's co-channel interference characteristics and transmits the precoded pilot signals on uplink. Using the responses of the precoded pilot signals, the BS determines appropriate weight vectors for downlink transmit beams considering the terminal's interference characteristics. Furthermore, the BS can predict the terminal's output signal-to-interference-plus-noise power ratio (SINR) for the downlink data stream. Numerical results show that the BS can achieve efficient transmission and accurate SINR prediction using the proposed CSI feedback.