Handling Jamming Attacks in a LoRa Network

With the proliferation of Internet of Things (IoT) applications relying on LoRa to gather data from dispersed devices, LoRa communications become prone to jamming attacks, which can cause massive packet loss, reduced throughput, and depleting batteries. Existing work related to jamming in LoRa mainly considers the impact of jamming and does not provide any anti-jamming techniques. Mitigating jamming in a LoRa network is extremely challenging as the devices have low computation power and limited energy typically supplied by small batteries. In this paper, we present a jamming mitigation technique for LoRa that imposes no overhead for energy-constrained nodes and can decode packets even when the SNR is ultra-low. We do this by exploiting the temporal and spatial variations of jammed signals of the same packet at different locations. Our design requires no change in LoRa nodes' physical layer, making it usable with all commercial off-the-shelf (COTS) LoRa devices. It works even under a powerful jammer with variable jamming signals, length of jamming packets, and mobility. Our jamming mitigation technique can be combined with existing collision recovery techniques for multiple LoRa packets to recover packets that collide with either jamming signal or with other LoRa packets of the same network. Finally, we evaluate the effectiveness of our jamming mitigation technique through outdoor experiments. The results show that our technique mitigates jamming by improving packet reception rate and energy consumption per packet up to 83.91 and 115.65 times, respectively, compared to the traditional LoRa.