On the Network Reliability Problem of the Heterogeneous Key Predistribution Scheme

Abstract: We consider the network reliability problem in wireless sensor networks secured by the heterogeneous random key predistribution scheme. This scheme generalizes Eschenauer-Gligor scheme by considering the cases when the network comprises sensor nodes with varying level of resources; e.g., regular nodes vs. cluster heads. The scheme induces the inhomogeneous random key graph, denoted $\mathbb{G}(n;\pmb{\mu},\pmb{K},P)$. We analyze the reliability of $\mathbb{G}(n;\pmb{\mu},\pmb{K},P)$ against random link failures. Namely, we consider $\mathbb{G}(n;\pmb{\mu},\pmb{K}, P,\alpha)$ formed by deleting each edge of $\mathbb{G}(n;\pmb{\mu},\pmb{K},P)$ independently with probability $1-\alpha$, and study the probability that the resulting graph i) has no isolated node; and ii) is connected. We present scaling conditions on $\pmb{K}$, $P$, and $\alpha$ such that both events take place with probability zero or one, respectively, as the number of nodes gets large. We present numerical results to support these in the finite-node regime.