Decode-and-cancel for interference cancellation in a three-node full-duplex network

In this paper, we study a three-node full-duplex network, where the infrastructure node has simultaneous up-and downlink communication in the same frequency band with two half-duplex nodes. In addition to self-interference at the full-duplex infrastructure node, the three-node network has to contend with the inter-node interference between the two half-duplex nodes. We characterize the impact of inter-node interference on the network achievable sum rate with and without a side-channel between the nodes. We propose and study a simple scheme called decode-and-cancel, which uses the side-channel for improved interference cancellation. We derive the sum rate for both Gaussian and fading channels. The results show that as signal-to-noise ratio becomes large, decode-and-cancel asymptotically achieves a multiplexing gain of 2 by means of optimal power allocation. Furthermore, the proposed decode-and-cancel scheme has the highest impact when the signal and inter-node interference have commensurate power in which case schemes without side channel fail to achieve any full-duplex multiplexing gain.