Optimal Resource Allocation in Full-Duplex Ambient Backscatter Communication Networks for Wireless-Powered IoT

TLDR

An ambient backscatter network is considered where a full‑duplex access point simultaneously transmits downlink OFDM to a legacy user and receives uplink backscattered signals from multiple backscatter devices in a TDMA fashion. The study aims to maximize the minimum throughput among all backscatter devices while ensuring fairness, by jointly optimizing backscatter time, reflection coefficients, and the access point’s subcarrier power under constraints on the legacy user’s throughput, device energy harvesting, and practical limits. Closed‑form solutions and a Lagrange‑dual algorithm are derived for a single device, whereas an iterative block‑coordinate descent with successive convex optimization is proposed for multiple devices, and the throughput region’s Pareto tradeoffs are also characterized. Simulations demonstrate that the joint design yields substantial throughput gains compared to benchmark schemes.

Abstract

This paper considers an ambient backscatter communication network in which a full-duplex access point (FAP) simultaneously transmits downlink orthogonal frequency division multiplexing signals to its legacy user (LU) and receives uplink signals backscattered from multiple backscatter devices (BDs) in a time-division-multiple-access manner. To maximize the system throughput and ensure fairness, we aim to maximize the minimum throughput among all BDs by jointly optimizing the backscatter time and reflection coefficients of the BDs, and the FAP's subcarrier power allocation, subject to the LU's throughput constraint, the BDs' harvested-energy constraints, and other practical constraints. For the case with a single BD, we obtain closed-form solutions and propose an efficient algorithm by using the Lagrange duality method. For the general case with multiple BDs, we propose an iterative algorithm by leveraging the block coordinated decent and successive convex optimization techniques. In addition, we study the throughput region which characterizes the Pareto-optimal throughput tradeoffs among all BDs. Finally, extensive simulation results show that the proposed joint design achieves significant throughput gain as compared to the benchmark schemes.