Analysis of Link Maintenance Probability for Cognitive Radio Ad Hoc Networks

Cognitive radio employs dynamic spectrum access technology to enhance the utilization of spectrum for ad-hoc networks. The unlicensed users or the secondary users make use of cognitive radio technology to bring into function the underutilized part of licensed spectrum pool by means of an opportunistic spectrum access strategy for their continuous transmission. Upon identifying the arrival of the primary users in the same channel, the secondary users are required to perform spectrum handoff in order to maintain the service link. Link establishment and continuous transmission are two prime issues for a superior link maintenance mechanism. In this paper, we present a Markovian model for opportunistic spectrum access to analyze the link maintenance probability of the secondary users in a heterogeneous spectrum environment of licensed and unlicensed spectrum pools. The mathematical expression for the link maintenance probability of the secondary user is derived in terms of their blocking probability and dropping probability in CR ad-hoc networks. The effect of arrival and service rates of primary and secondary users on link maintenance probability is also presented considering the presence of classical users.