Optimal pilot overhead for FDD full-duplex communication and radar sensing (ComSens)

In this paper, we propose and analyze new spectrum-efficient communication and radar sensing systems (named ComSens) operating in full-duplex mode with frequency division duplex scheme. ComSens simultaneously use the pilot overhead for channel estimation and radar sensing. The performances of ComSens are analyzed in terms of ergodic communication data-rate and radar estimation rate. The total system rate is optimized with respect to the pilot overhead size and the pilot powers. The numerical results show that the optimization of the pilot overhead is critical for ComSens. The radar-estimation rate increases with pilot size, pilot power, and self-interference cancellation level. With an average self-interference cancellation of 110 dB, our radar-estimation rate values are similar to the radar-estimation rate values derived for a stand-alone radar system.