Throughput and Energy Aware Range Maximization in Cooperative Backscatter Communication Systems

This paper explores a novel cooperative timing protocol in two-user backscatter communication (BSC) network, where one Reader transmits a wireless energy signal to two collaborative backscatter tags. These tags modulate the incident signal and backscatter its information to the Reader. Specifically, the tag closer to the Reader uses its resources to help relay the far tag's information to the Reader to reduce the effect of the doubly near-far problem in BSC. We aim to maximize the transmission range of the farther tag while satisfying the Quality of Service (QoS) requirement in terms of throughput and energy threshold. First, we derive the necessary conditions for the proposed problem's feasibility for throughput and energy constraints. Then, we solve this non-convex range maximization problem by alternatively optimizing the time allocation for maximizing minimum throughput and energy, respectively, and the transmission range. The numerical simulations have been conducted to provide insight into the impact of energy and throughput base QoS demand on the achievable transmission range. The average gain of the proposed cooperative BSC over the non-cooperative one is > 20%.