Dynamic spectrum access technology is a kind of technology that provides a solution to the spectrum scarce problem. The most important issue in the CR network (both primary users and secondary users coexists in the network) is that the traffic of secondary users should not affect the primary users communication. In order to not affect the primary users, we have to detect the existence of the primary users. Therefore, the spectrum sensing is needed for this. However, it is very important to design a proper spectrum sensing scheme. Since detection accuracy of the primary users activities and the throughput of the network can be dramatically affected by the spectrum sensing scheme. Therefore, we propose an improved spectrum sensing scheme which take the protocol of the MAC layer into consideration in this paper. The simulation helps to show that our proposed novel method improves the throughput of the network dramatically.