A spectrum handoff scheme based on comprehensive cost in cognitive radio system

In the cognitive radio networks, the spectrum handoff scheme directly determines the system performance. That´s to say a handoff scheme that cannot fully uses the information of users and channels will not provide the best choice. In this paper, a spectrum handoff scheme based on comprehensive cost is proposed. By jointly computing multiple factors such as transmission delay, channel bandwidth, SNR and the characteristics of users and so on, we get a Judgment Matrix for channel selection so that we can give consideration to all these factors´ influence on the final system performance. In this paper we also set up a cognitive radio scenario to simulate the process and verify our scheme. Comparing with the random access scheme, the simulation results show that our scheme can reduce the probability of spectrum handoff and enhance the throughput capacity significantly and finally result in larger service carrying capacity and lower service drop number.