Cooperative relay strategy for backscatter communication networks with RF energy harvesting

Backscatter sensors have emerged as a viable option for battery-less wireless networks, especially for the next generation Internet-of-Things (IoT) systems. Due to its simple hardware and support for wireless power transfer, it is well suited for the implementation of IoT networks. In this paper, we consider a backscatter relay network where backscatter devices are wirelessly powered by a hybrid access point (HAP). The signals beamformed by the HAP also act as carrier emitters for backscatter devices to modulate and transmit data. Some backscatter devices are unable to directly communicate with the HAP. Nearby backscatter devices present in the network assist these devices with a goal of providing access to the HAP and improving their throughput via cooperative transmission. A maximization problem is formulated to maximize the overall throughput of a distant device with a relay strategy for the considered backscatter relay network. We also propose a procedure to acquire accurate channel information of all the channels to ensure efficient beamforming at the HAP. Numerical results show that accurate channel information can significantly improve the overall throughput of the proposed backscatter relay network. Performance evaluation of the proposed scheme shows the effect of different system parameters on the overall system throughput.