On the Analysis of Network Connectivity in Cognitive Radio Ad-Hoc Networks

Network connectivity is one of important issues in any kinds of networks. In this paper, we discuss the connectivity challenges in Cognitive Radio Ad-Hoc Networks (CRAHNs) compared with conventional mobile ad-hoc wireless networks. We conclude that network connectivity in cognitive radio ad-hoc networks depends on not only node density, but also the spectrum heterogeneity. Our main contributions in this paper are follows: (i) to define and classify the conditions of connectivity in cognitive ad-hoc networks, (ii) to mathematically analyze how each condition degrades the network connectivity, (iii) to derive final closed-form model to show the total impact of all network parameters on network connectivity in CRAHNs. The results obtained from our proposed mathematical models point out several distinguishing features of network connectivity in CRAHNs compared with those of conventional mobile ad-hoc wireless networks. Specifically, we prove mathematically that the network connectivity in CRAHNs depends on SU's node density, PU's node density, PU's activating rate, operating frequencies, the number of licensed channels, and the distribution of PUs on each channel. Our proposed mathematical model can be used to support the evaluation and design of CRAHNs.