Efficient spectrum handoff scheme in cognitive radio

In cognitive radio system, the efficiency of spectrum handoff is always a challenge. To conquer this difficulty, classification and matching scheme is adopted. The users are classified according to their type of services at first, and then a reliable channel evaluation is designed to match the classifications of the users´, at last, a dynamic programming (DP) algorithm is adopted to decrease the latency of handoff among each group of channels further. This spectrum handoff scheme based on classification and matching is efficient when the users´ number is large. Simulation results show that the proposed algorithm is a viable method of prompting spectrum handoff efficiency, and reducing congestion probability, handoff number and handoff delay.