Routing Protocols on Cognitive Radio Networks: Survey

Cognitive Radio is a technology that has emerged to solve the problem of frequency resources underutilization caused by the non-use of a large part of radio spectrum. Cognitive Radio permits an opportunistic and effective use of the existing spectrum taking advantage of white spaces thanks to listening and adaptation ability towards the environment. However, Cognitive Radio Networks impose unique challenges because of their coexistence with primary networks (licensed networks) as well as quality of service requirements. All protocol layers of the network are affected by these challenges; in this paper we highlight the network layer side and give a survey of routing techniques in Cognitive Radio Network. Firstly we give an overview of Cognitive Radio, introduce the routing process and outline routing challenges, then we classify routing protocols and give a particular focus on routing algorithms, we present a comparison study of some Cognitive Radio routing protocols and finally end with some domain of applications and possible future research directions.