Abstract:

To solve the problem that secondary users cannot real-timely obtain arrival rates and service rates of primary users during the handoff period, a parameter estimation algorithm based on the hidden Markov model is proposed. Firstly, primary user queues are modeled and analyzed by the queue theory, and the state transition probability of primary user queues is derived. Real states of primary user queues are detected by the energy sensing algorithm, so that observable sequences are obtained. Then, two kind of stochastic processes are described by the hidden Markov process, namely， the stochastic process of state transition of primary user queues and the stochastic process of observable sequences. Finally, the hidden Markov process is estimated by the forward-backward algorithm, so that the arrival rate and the service rate of primary users are obtained. Simulation results verify that real-time and relatively accurate estimation can be realized, and a foundation for secondary users is provided to choose a spectrum handoff strategy in real time.