Cognitive Radio Ad-hoc Networks: A Routing Perspective

Cognitive radio is considered the enabling technology of the dynamic spectrum access paradigm which is envisaged to solve the spectrum scarcity problem, thus facilitating the accommodation of new wireless services as well as providing an effective solution to the ever increasing user demand. It allows the unlicensed users to utilize dynamically and opportunistically the spectrum assigned to the primary users, when it is temporarily not used. To reach this aim, unlicensed users must be able to change their transmission and reception parameters to communicate with each other without causing interference to the primary users. The main objective of this thesis is to address the routing problem under the challenging scenario characterized by the uncertain availability of the spectral resource. The routing problem is furthermore challenging in presence of primary user's mobility. To deal with this scenario, we proposed to utilize jointly path and spectrum diversity in routing to assure an improved spectral efficiency. We also proposed a mobility-aware channel-availability based channel selection technique, which performs the best channel selection in terms of spectrum availability in presence of primary user's mobility. Performance evaluation is conducted through simulations, and the simulation results reveal the benefits of introducing the proposed proposals.