Design and Implementation of NOMA Backscatter Communication with Low-Precision Oscillators

Recent years have witnessed increasing demands for the large-scale deployment of Internet-of-things (IoT) devices. Backscatter technologies are promising to meet these demands with the notable low power consumption and cost. However, the conventional designs of backscatter prioritize energy efficiency at the cost of multiple access schemes with low spectral efficiency, which hinders its large-scale deployments. In this paper, we propose a new non-orthogonal multiple access backscatter (NOMA-Backscatter) system to meet high spectral-efficiency requirement. We implement the NOMA-Backscatter system for the first time with resource-constrained low-cost and low-power hardware and eliminate the affects of unstable oscillators during the successive interference cancellation (SIC) demodulation process in real world. Results demonstrate that NOMA-Backscatter can achieve 1.38 Mbit/s throughput with 200% tag load, and the spectral efficiency is 1.73× higher than state-of-the-art backscatter systems.