Attack-aware Synchronization-free Data Timestamping in LoRaWAN

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

11 Scopus Citations
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Original languageEnglish
Article number10
Journal / PublicationACM Transactions on Sensor Networks
Issue number1
Online published5 Oct 2021
Publication statusPublished - Feb 2022
Externally publishedYes


Low-power wide-area network technologies such as long-range wide-area network (LoRaWAN) are promising for collecting low-rate monitoring data from geographically distributed sensors, in which timestamping the sensor data is a critical system function. This article considers a synchronization-free approach to timestamping LoRaWAN uplink data based on signal arrival time at the gateway, which well matches LoRaWAN's one-hop star topology and releases bandwidth from transmitting timestamps and synchronizing end devices' clocks at all times. However, we show that this approach is susceptible to a frame delay attack consisting of malicious frame collision and delayed replay. Real experiments show that the attack can affect the end devices in large areas up to about 50,000 m2. In a broader sense, the attack threatens any system functions requiring timely deliveries of LoRaWAN frames. To address this threat, we propose a LoRaTS gateway design that integrates a commodity LoRaWAN gateway and a low-power software-defined radio receiver to track the inherent frequency biases of the end devices. Based on an analytic model of LoRa's chirp spread spectrum modulation, we develop signal processing algorithms to estimate the frequency biases with high accuracy beyond that achieved by LoRa's default demodulation. The accurate frequency bias tracking capability enables the detection of the attack that introduces additional frequency biases. We also investigate and implement a more crafty attack that uses advanced radio apparatuses to eliminate the frequency biases. To address this crafty attack, we propose a pseudorandom interval hopping scheme to enhance our frequency bias tracking approach. Extensive experiments show the effectiveness of our approach in deployments with real affecting factors such as temperature variations. © 2021 Association for Computing Machinery.

Research Area(s)

  • data timestamping, LoRaWAN, Low-power wide-area networks, wireless security

Citation Format(s)

Attack-aware Synchronization-free Data Timestamping in LoRaWAN. / GU, Chaojie; JIANG, Linshan; TAN, Rui et al.
In: ACM Transactions on Sensor Networks, Vol. 18, No. 1, 10, 02.2022.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review