Abstract
With the development of the Internet of Things (IoT), the amount of transmitted data is getting huge. Traditional passive UHF CRFID Tag currently adopts 2ASK or 2PSK backscatter modulation, and each symbol conveys 1 bit of information. Still, this modulation has the problems of low throughput, poor real-time, and low energy utilization. This paper proposes an optimal 4 Quadrature Amplitude Modulation (4QAM) backscatter scheme at 920 MHz, which can increase the throughput and simultaneously improve energy utilization. In this optimal scheme, the reflection coefficient modulus |Γ| is closely related to the energy. The low power of the passive tag requires that the modulation circuit’s design consider how to choose |Γ|opt (optimal reflection coefficient modulus). Therefore, we build the energy model of CRFID to explore the |Γ|opt at different symbol rates and use the |Γ|opt to design a more reasonable constellation diagram for passive tags. Finally, this paper analyzes the decoding of multinary backscatter signals, and an improved Kmeans algorithm can solve the cluster offset problem at high symbol rates. After experiments, |Γ|opt is around 0.67, the maximum throughput of 4QAM backscatter modulation can reach 16 Mbit/s, and the power consumption is 4.38 mW. Compared with the traditional binary modulation, the tag in this paper can double the throughput at the same symbol rate.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
