Electronics, Vol. 14, Pages 4258: Ambient Carrier Interference Cancellation for Backscatter in Distributed PV Systems

Electronics doi: 10.3390/electronics14214258

Authors:
Xu Liu
Xiaobing Xiao
Guanghui Zhang
Wu Dong
Yongxiang Cai
Qing Liu
Yueyao Wang
Da Chen
Wei Wang

Despite the promising prospects of reusing ambient carriers for ultra-low-power communication, backscatter tags also suffer severe interference from ambient carriers, which limits their performance. Existing backscatter approaches avoid interference by shifting scattered signals away from the carrier, leading to spectral wastage and making large-scale deployment impractical. To address this issue, this paper proposes the first Ambient Carrier Interference Cancellation (ACIC) system for backscatter communication, especially tailored for Distributed photovoltaic (PV) scenarios. ACIC has the following novel components: (i) a carrier-detecting scheme that detects and filters out the carrier from the received ambient signals; (ii) an adaptive interference-cancellation system that cancels the carrier with programmable phase shift and attenuator; (iii) an acceleration algorithm to enhance the speed of the cancellation. We then implement the ACIC system and conduct comprehensive experiments to evaluate its performance. Our results demonstrate that the ACIC system achieves greater than 40 dB interference cancellation, both with and without a backscatter tag. Unlike frequency-shifting schemes that sacrifice spectral efficiency, our ACIC achieves in-band carrier cancellation, reducing BER from 0.5 to 0.03 at 0.5 m distance. This improvement enables reliable and scalable battery-free sensing in distributed PV systems.

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Xu Liu www.mdpi.com