Finding an Immuned Path Against Single Primary User Activity in Cognitive Radio Networks
Sharhabeel H. Alnabelsi · International Journal on Communications Antenna and Propagation (IRECAP) · 2017
Due to recent crowdedness in unlicensed spectrum, a new technology is introduced which allows unlicensed users, also known as Secondary Users (SUs), to dynamically access licensed spectrum whenever they are not used by their licensed users, also known as Primary Users (PUs). Routing in Cognitive Radio Networks (CRNs) is not as in traditional routing of wireless networks, because it is mandatory for SUs to periodically sense licensed spectrum, channels availability changes over time, knowledge of tolerated interference by PUs. In this paper, a novel routing discovery technique is proposed to find a primary path, if exist, which is immuned to one PU, such that at most one SU fails (must back off transmission) when a PU becomes active again. Also, a backup path can be discovered using the same technique with the condition that it is channel-link disjoint from the primary path. The problem is modeled using a multi-layer graph where each layer corresponds to a channel in a network. The proposed strategy reduces number of required channel-links maintenance to two, if failed due to one PU activity. As a result, SUs’ energy consumption is reduced when re-establishing route connectivity, and therefore, network life time is prolonged.