Design of multi-element QAM backscatter modulated tag based on backscatter communication

Abstract

The low throughput of backscatter systems impedes Internet of Things (IoT) deployment. Although coding optimization and rate adaptation schemes exist for low-order modulation, inherent modulation constraints still limit large-data transmission in complex channels. In addition, the design scheme of fixed high-order modulation tags has poor environmental robustness. In order to solve the above problems, this paper designs a low-power multiple quadrature amplitude modulation(MQAM) modulated tag with an operating frequency of 920 MHz. The modulation space is significantly enlarged by optimizing the selection of reflection coefficient, designing series impedance branch and double \(\Pi\)\(\mu\)s) is realized at the tag end based on LMV331 comparator. The experimental results show that the tag can achieve an average throughput of 15.36 Mbit/s at a communication distance of 1.8 m and a power consumption of 0.57 mW, which is a significant increase in throughput compared with the traditional low-order tags, and also has a significant advantage over the fixed high-order modulation tags in terms of communication distance and power consumption.