Jinyan Jiang, Zhenqiang Xu, Fan Dang, Jiliang Wang
{"title":"Long-range ambient LoRa backscatter with parallel decoding","authors":"Jinyan Jiang, Zhenqiang Xu, Fan Dang, Jiliang Wang","doi":"10.1145/3447993.3483261","DOIUrl":null,"url":null,"abstract":"LoRa backscatter is a promising technology to achieve low-power and long-distance communication for connecting millions of devices in the Internet of Things. We present P2LoRa, the first ambient LoRa backscatter system with parallel decoding and long-range communication. The high level idea of P2LoRa is to modulate data by shifting ambient LoRa packets with a small frequency. To achieve long distance communication, we enhance the SNR of the backscatter signal by concentrating leaked energy in both the frequency domain and time domain. We propose a method to accurately reconstruct and cancel the in-band excitation signal, which is orders of magnitude higher than the backscatter signal. For parallel decoding, we propose a method to cancel inter-tag interference with very low overhead and address the signal misalignment problem due to different time of flight. We prototype the P2LoRa tag with customized low-cost hardware and implement the P2LoRa gateway on USRP. Through extensive evaluations, we show that P2LoRa achieves a long communication distance of 2.2 km with ambient LoRa, and supports 101 parallel tag transmissions.","PeriodicalId":177431,"journal":{"name":"Proceedings of the 27th Annual International Conference on Mobile Computing and Networking","volume":"70 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"36","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 27th Annual International Conference on Mobile Computing and Networking","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1145/3447993.3483261","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 36
Abstract
LoRa backscatter is a promising technology to achieve low-power and long-distance communication for connecting millions of devices in the Internet of Things. We present P2LoRa, the first ambient LoRa backscatter system with parallel decoding and long-range communication. The high level idea of P2LoRa is to modulate data by shifting ambient LoRa packets with a small frequency. To achieve long distance communication, we enhance the SNR of the backscatter signal by concentrating leaked energy in both the frequency domain and time domain. We propose a method to accurately reconstruct and cancel the in-band excitation signal, which is orders of magnitude higher than the backscatter signal. For parallel decoding, we propose a method to cancel inter-tag interference with very low overhead and address the signal misalignment problem due to different time of flight. We prototype the P2LoRa tag with customized low-cost hardware and implement the P2LoRa gateway on USRP. Through extensive evaluations, we show that P2LoRa achieves a long communication distance of 2.2 km with ambient LoRa, and supports 101 parallel tag transmissions.