Wireless Information and Power Transfer With Full Duplex Relaying

TLDR

The study analyzes a dual‑hop full‑duplex relay powered by RF energy via a time‑switching architecture, deriving analytical throughput expressions for amplify‑and‑forward and decode‑and‑forward protocols under instantaneous, delay‑constrained, and delay‑tolerant transmission modes and optimizing the time‑splitting ratio for each. Optimizing the time‑split shows that full‑duplex relaying markedly increases throughput over half‑duplex for all modes, with instantaneous transmission achieving the highest rates, a modest gap to delay‑constrained operation, and the delay‑constrained optimal split relying only on channel statistics, making it practical.

Abstract

We consider a dual-hop full-duplex relaying system, where the energy constrained relay node is powered by radio frequency signals from the source using the time-switching architecture, both the amplify-and-forward and decode-and-forward relaying protocols are studied. Specifically, we provide an analytical characterization of the achievable throughput of three different communication modes, namely, instantaneous transmission, delay-constrained transmission, and delay tolerant transmission. In addition, the optimal time split is studied for different transmission modes. Our results reveal that, when the time split is optimized, the full-duplex relaying could substantially boost the system throughput compared to the conventional half-duplex relaying architecture for all three transmission modes. In addition, it is shown that the instantaneous transmission mode attains the highest throughput. However, compared to the delay-constrained transmission mode, the throughput gap is rather small. Unlike the instantaneous time split optimization which requires instantaneous channel state information, the optimal time split in the delay-constrained transmission mode depends only on the statistics of the channel, hence, is suitable for practical implementations.