Full-Duplex in Wireless Communications

In-band full-duplex transceivers are able to transmit and receive simultaneously at the same frequency band. In wireless communications, such technology can offer potentially 100% increase in throughput when uplink and downlink simultaneously share the same band(s). In practice, this requires that a full-duplex device is able to mitigate the inherent self-interference caused by the leakage of the transmitted signal to the receiver chain. On the network level, full-duplex devices change the statistics of cochannel interference in the system, which must be handled with appropriate medium access control. In addition, the capability of transmitting and receiving simultaneously gives gain only when there is enough buffered data to be transmitted in both ways. In practice, the gain from full-duplex operation is less than 100%, but nevertheless theoretical studies and full-duplex prototypes have demonstrated that it can still be substantial. This article presents an overview of the state-of-the-art full-duplex technology in wireless communications describing its performance and discussing challenges to make full-duplex operation widely adopted in emerging systems.