Strength of Crowd (SOC)—Defeating a Reactive Jammer in IoT with Decoy Messages

We propose Strength of Crowd (SoC), a distributed Internet of Things (IoT) protocol that guarantees message broadcast from an initiator to all network nodes in the presence of either a reactive or a proactive jammer, that targets a variable portion of the radio spectrum. SoC exploits a simple, yet innovative and effective idea: nodes not (currently) involved in the broadcast process transmit decoy messages that cannot be distinguished (by the jammer) from the real ones. Therefore, the jammer has to implement a best-effort strategy to jam all the concurrent communications up to its frequency/energy budget. SoC exploits the inherent parallelism that stems from the massive deployments of IoT nodes to guarantee a high number of concurrent communications, exhausting the jammer capabilities and hence leaving a subset of the communications not jammed. It is worth noting that SoC could be adopted in several wireless scenarios; however, we focus on its application to the Wireless Sensor Networks (WSN) domain, including IoT, Machine-to-Machine (M2M), Device-to-Device (D2D), to name a few. In this framework, we provide several contributions: firstly, we show the details of the SoC protocol, as well as its integration with the IEEE 802.15.4-2015 MAC protocol; secondly, we study the broadcast delay to deliver the message to all the nodes in the network; and finally, we run an extensive simulation and experimental campaign to test our solution. We consider the state-of-the-art OpenMote-B experimental platform, adopting the OpenWSN open-source protocol stack. Experimental results confirm the quality and viability of our solution.