Backscatter Relay Communications Powered by Wireless Energy Beamforming

TLDR

The integration of wireless power transfer with low‑power backscatter communications offers a promising approach to sustain battery‑less wireless networks. The study investigates a backscatter communication network powered by a power beacon station and formulates a throughput‑maximization problem that jointly optimizes wireless power transfer and relay strategy. The authors design an iterative, low‑complexity algorithm that decomposes the joint WPT–relay optimization into PBS‑ and receiver‑side subproblems, incorporates channel uncertainty through robust formulations, and solves the resulting coupled matrix‑inequality constraints via alternating optimization with guaranteed convergence. Simulation results show that cooperative relaying among backscatter radios markedly boosts throughput.

Abstract

The integration of wireless power transfer (WPT) with the low-power backscatter communications provides a promising way to sustain battery-less wireless networks. In this paper, we consider a backscatter communication network wirelessly powered by a power beacon station (PBS). Each backscatter radio uses the harvested energy to power its data transmissions, in which some other radios can help as the wireless relays with an aim to improve throughput performance by cooperative transmission. Under this setting, we formulate a throughput maximization problem to jointly optimize WPT and the relay strategy of the backscatter radios. An iterative algorithm with reduced complexity and communication overhead is proposed to decompose the original problem into two sub-problems distributed at the PBS and the backscatter receiver. Moreover, we take uncertain channel information into consideration and formulate robust counter-parts of the throughput maximization problem when either the backscatter or relay channel is subject to estimation errors. The difficulty of the robust counter-part lies in the coupling of the PBS' power allocation and relay strategy in matrix inequalities, which is addressed by alternating optimization with guaranteed convergence. Numerical results reveal that the cooperative relay strategy of the backscatter radios significantly improves the throughput performance.