Abstract:As there is rapid development of wireless and mobile communications, limited opening band is unable to meet the growing usage of mobile communication. In order to make better use of scarce spectrum resources, Cognitive Radio (CR) has been proposed to exploit underutilization portions of the spectrum, which is capable of interference sensing, environmental learning, and dynamic spectrum access. In this paper, a new routing algorithm for Cognitive Radio networks has been proposed. The algorithm is based on atomic time, known as DDCR (DillyDally Cognitive Routing). The DillyDally path is found by calculating the transmission delay of given packets on every link (weighted link). The transmission delays are found by using classic Dijkstra algorithm. Simulation results show the End-End delay of DDCR is less than that of the traditional routing algorithm. Thereby the network performance is improved.