Throughput Fairness Guarantee in Wireless Powered Backscatter Communications With HTT

Harvest-then-transmit (HTT) and backscatter communications have different tradeoffs between energy harvesting and data transmission and may complement each other for increasing the achievable throughput, which however has not been sufficiently exploited by the existing works. In this letter, we propose a max-min throughput based resource allocation scheme for a wireless powered Internet of Things (IoT) network to ensure the fairness among multiple sensor nodes (SNs), which harvest energy from the signals transmitted by a power beacon (PB) and convey their information to an information receiver (IR) by backscattering, HTT, or the hybrid of them. We introduce a series of auxiliary variables to transform the non-convex max-min throughput problem into a convex one. We show that the max-min throughput is achieved when the SN with the worst link, which achieves the minimum throughput, consumes all the harvested energy and works in the hybrid of backscattering and HTT. Simulation results show that compared with the sum-throughput maximization scheme, our developed resource allocation scheme achieves a much better throughput fairness, while maintaining almost the same average throughput.