An Optimal Channel Selection Policy Based on POMDP for Maximizing Secondary User Performance in Cognitive Network

Shehana Badar J

Abstract: In the absence of primary users, cognitive radio allows the secondary users to access the ?underutilized? primary user band. Whenever the PU need of its bands, SU is interrupted from its data transmission. Periodic Spectrum Sensing (PSS) scheme degrades the QoS of the SU by interrupting its data transmission over the entire PU band. To alleviate this problem, the PU band is divided into two sub bands. One for continuous spectrum sensing and the other for SU data transmission, Based on this band division two schemes are proposed, a delay oriented continuous spectrum sensing (DO-CSS) scheme and throughput oriented continuous spectrum (TO-CSS) scheme. In the DO-CSS scheme, the average SU transmission delay is reduced by proper selection of bandwidth for spectrum sensing within each frame. In the TO-CSS scheme the achievable average throughput of the SU is maximized by choosing the optimal sensing bandwidth within multiple adjacent frames. The throughput is further improved by using an optimal sensing channel selection policy based on partially observable markov decision process.

Keywords: Periodic spectrum sensing, continuous spectrum sensing, delay oriented, throughput oriented, sensing bandwidth, optimal sensing