Full-duplex communication and channel reciprocity

Abstract

In-band full-duplex communication is a promising technique for future 5G systems, where transmission and reception of signals are run simultaneously on the same frequency band. However, some considerable signal power from the transmitter inevitably leaks as self-interference into the receiver chain and therefore needs to be effectively removed.
The demo at hand shows a two-way image transmission, where the software-defined radio nodes are capable of full-duplex communication. The self-interference cancellation is implemented by a circulator in the analog domain and an adaptive digital algorithm based on Kalman filtering. Furthermore, secret-key generation from reciprocal wireless channels has been identified as a supplement for secret-key distribution in wireless networks. Our demo shows real-time, two-way channel measurements that indicate the feasibility of such an approach.