NOMA-Enabled Backscatter Communications: Toward Battery-Free IoT Networks

A new wireless era beckons, giving rise to novel communication techniques to support the services and demands foreseen for the coming decades. One such revolutionizing technique intended to enable the Internet of Things (IoT) is backscatter communication. Simply employing backscatter communication may not be enough to efficiently connect the massive number of devices in the IoT network. To achieve this feat, non-orthogonal multiple access (NOMA) techniques have been merged with backscatter communications. Although NOMA-enabled backscatter communication is expected to significantly improve the low-powered IoT system, the benefits come with several challenges. In this article, we show that NOMA-enabled backscatter communication has the potential to connect a large number of IoT devices in a battery-free manner. To begin, this article provides the basics on backscatter communication and NOMA techniques. Next, a taxonomy and gap analysis of the studies on backscatter communication is provided. Then novel use cases for NOMA-enabled backscatter communication are detailed, and a case study for smart farming using the overall data rate of backscatter sensor devices employing power-domain NOMA is presented. Finally, we discuss some interesting and potential research challenges to the realization of massive IoT networks using NOMA-enabled backscatter communication.