Dynamic Spectrum Access with QoS Guarantee for Wireless Networks: A Markov Approach

Dynamic spectrum access has become a promising technique to fully utilize the scarce spectrum resources. However, spectrum allocation schemes with high efficiency and Quality of Service (QoS) guarantee for the primary users have yet to be designed. In this paper, two novel dynamic spectrum access schemes are proposed. The proposed schemes are based on continuous-time Markov chains (CTMC), through which the interactions between primary and secondary users are explicitly modeled. The effects of sensing errors (i.e. miss-detection and false alarm) are taken into consideration. Since miss-detection may lead to collision between primary and secondary users and false alarm will leave spectrum opportunities unused, we derive the optimal access probabilities for each secondary user, so that the QoS of primary user in terms of collision probability constraint is guaranteed, and the missing spectrum opportunities caused by false alarm can be utilized by secondary users. Simulation results show that the proposed schemes can guarantee primary user´´s QoS effectively. Moreover, the scheme with buffer can improve the channel occupancy remarkably.