Enhancing full-duplex information transfer by RF energy harvesting

In practical implementations of single-Antenna full-duplex (FD) radios, the imperfect isolation between the transmit (TX) and receive (RX) ports of the circulator causes the leakage of a strong self-interference (SI) component. This issue reduces both the spectral and energy efficiency of the device. State-of-The-Art SI cancellation (SIC) solutions mitigate this problem, however they also constrain the maximum TX power of the FD radio. To address these issues and restrictions, we propose an energy recycling FD architecture that improves both the SIC capability and the spectral/energy efficiency of FD devices by means of a suitable radio frequency (RF) energy harvesting. The benefits brought by such solution are analyzed in an uplink (UL) scenario where two FD access points (APs), operating according to the proposed FD architecture, exchange signaling messages via a wireless link while communicating with two half-duplex (HD) mobile users (MUs). Our findings highlight non-negligible performance enhancements as compared to state-of-The-Art approaches. Specifically, the proposed architecture is shown to yield a rate enhancement up to 29% for both UL transmission and signaling, and the recycling of up to 50% of the wasted energy at the circulator.