This paper investigates the impact of reactive jamming on LoRaWAN networks, focusing on showing that LoRaWAN communications can be effectively disrupted with minimal jammer exposure time. The susceptibility of LoRa to jamming is assessed through a theoretical study of how the frame success rate is impacted by only a few jamming symbols. Different jamming approaches are studied, among which repeated-symbol jamming appears to be the most disruptive, with sufficient jamming power. A key contribution of this work is the proposal of a software-defined radio (SDR)-based jamming approach implemented on GNU Radio that generates a controlled number of random symbols, independent of the standard LoRa frame structure. This approach enables precise control over jammer exposure time and provides flexibility in studying the effect of jamming symbols on network performance. The theoretical analysis is validated through experimental results, where the implemented jammer is used to assess the impact of jamming under various configurations. Our findings demonstrate that LoRa-based networks can be disrupted with a minimal number of symbols, emphasizing the need for future research on stealthy communication techniques to counter such jamming attacks.

翻译：本文研究了反应式干扰对LoRaWAN网络的影响，重点论证了在极短的干扰暴露时间内即可有效破坏LoRaWAN通信。通过理论分析仅需少量干扰符号即可影响帧成功率，评估了LoRa对干扰的脆弱性。研究比较了多种干扰方法，其中在足够干扰功率条件下，重复符号干扰表现出最强的破坏性。本工作的核心贡献在于提出了一种基于软件定义无线电（SDR）的干扰方法，该方法在GNU Radio平台上实现，可生成与标准LoRa帧结构无关的受控随机符号序列。此方法能精确控制干扰暴露时间，并为研究干扰符号对网络性能的影响提供了灵活性。通过实验验证了理论分析，利用所实现的干扰器评估了不同配置下的干扰效果。研究结果表明，基于LoRa的网络仅需极少量符号即可被破坏，这凸显了未来需研究隐蔽通信技术以抵御此类干扰攻击的必要性。