Abstract
Cooperative behavior is vital to Cognitive Radio Networks (CRN), which has the distributed nature. Time synchronization is the basic to cooperation. Many protocols are developed. However, they are either rather complicated or relying on infrastructure such as GPS. In this paper, a physical layer approach is proposed. Without complex protocols and not reliable to other systems, this approach has a better efficiency. The synchronization method is proposed and the corresponding platform is demonstrated. The analysis on how the error of synchronization deteriorates the performance is given and the solutions are shown thereafter.