A single frequency full-duplex radio relay station for Frequency Domain Equalization systems

Full-duplex radio relay station using a single frequency for receiving and transmitting signals requires coupling wave (self-interference) canceller in order to avoid oscillation. In this paper, we propose a coupling wave cancellation scheme for the relay station in the FDE (Frequency Domain Equalization) system. The proposed relay station utilizes a blind coupling canceller composed by an actual antenna element and virtual coupling wave paths as each element of receiving adaptive antenna array, and controls the weights of the adaptive array so that the SNR (Signal-to-Noise Ratio) at the FDE output, which is virtually-placed after the adaptive array, is maximized. With the proposed approach, we can achieve the coupling wave cancellation and multiple desired signal reception, which increases the received desired signal power, without noise enhancement at the FDE of the destination terminal. The BER (Bit Error Rate) performance of the proposed method is demonstrated via computer simulations.