Enabling broadcast communications in presence of jamming via probabilistic pairing

Abstract

This paper presents a thorough analysis of Freedom of Speech (FoS): a lightweight, fully distributed, and probabilistic protocol that assures the delivery of a message to be broadcast notwithstanding the presence of a jammer. FoS enjoys several features when compared to competing schemes: (i) it requires each node to store only N symmetric pairwise keys; (ii) node joining and node eviction require just minimal intervention on the already operating nodes; and, finally, (iii) it is overall highly efficient in terms of required computation and message exchange. We provide a detailed theoretical analysis of our solution supported by extensive simulations considering different operating scenarios: we start from a simplified network assumption of one only transmitter that wants to broadcast a message and we subsequently move to a realistic scenario where nodes that have received the message act themselves as a proxy. We propose a theoretical framework to model the protocol performance starting by a benign scenario (no jamming activities). Later, we extend the model to more hostile environments considering firstly a jammer with no knowledge of the nodes' secret keys (external jammer) and subsequently, a jammer aware of a fraction of the nodes' secret keys (internal jammer). The experimental results do confirm our theoretical analysis and show the overall viability of our solution. In particular, FoS outperforms competitor solutions for deployment scenarios characterized by even a moderated degree of node volatility.