Fast and low-cost discovery of spectrum opportunities based on proper sensing interval

As the development of the cognitive radio (CR) technology attracts more and more people´s attention, the problems involving the usage of the CR are urgently to be solved. In this paper, we focus on the speed and the cost of the spectrum opportunities from the view of the sensing interval. Intrinsically, high speed and low cost are on the contrary. And the tradeoff of the two performances is just the point of this paper. We deduce the function of the discovery delay and the consumed energy as the increase of the sensing interval in single and multi channel condition respectively. Then the tradeoff is given in the form of the expression. And also we explain the selection problems of the interval and the channel number through the simulation, which will be a great contribution to the usage of the CR.