A Novel Reduced Sensing Time Routing Protocol in Cognitive Radio Networks

Cognitive Radio Networks (CRNs) technology is developed, in order to utilize wireless licensed channels more efficiently, due to the fact that ISM channels became over crowded. Cognitive Radio (CR) technology empowers unlicensed users, also known as Secondary Users (SUs), to opportunistically access licensed channels and transmit when currently are not occupied by their corresponding licensed users, also known as Primary Users (PUs). When a SU is utilizing a licensed channel and its PU becomes active again, the SU must back-off immediately. Therefore, a periodic channel sensing by SUs is required, to avoid a harmful interference to PUs' transmission. In this work, we present a novel Cooperative Spectrum Sensing (CSS) approach between SUs along the selected route in ad-hoc CRNs, this approach is called a Reduced Sensing Time Routing Protocol (RSTRP). We assume when a routing path is established, it will be sustained for a while. We propose that each SU along the route may cooperate with neighbor SUs which are eligible to conduct channels sensing on its behalf, if possible. Therefore, this saved time can be utilized to prolong transmission time, so that the total End-to-End (E2E) delay over the selected route is reduced.