A Factor Graph Approach to Digital Self-Interference Mitigation in OFDM Full-Duplex Systems

Digital self-interference cancellation is a major challenge for orthogonal frequency division multiplexing full-duplex transmissions. Therefore, reliable estimation of both the signal-of-interest and the self-interference channel, becomes the limiting factor in a mobile radio context. In this letter, improved estimation of the time-varying channels is obtained by solving the problem jointly with self-interference cancellation and decoding using a factor graph approach. Taking advantage of the per-subcarrier structure of message-passing, a low-complexity receiver is obtained. Our semianalytical and numerical results show the superiority of the proposed scheme over state-of-the art self-interference cancellation methods under limited pilot overhead.