On the use of POMDP for Spectrum Selection in Cognitive Radio Networks

Dynamic Spectrum Access is a key capability of Cognitive Radio (CR) networks to increase the efficiency in the use of the available spectrum resources. In this respect, this paper focuses on the spectrum selection problem when a number of radio links has to be established in a CR network to support applications with different bit rate requirements. A novel strategy based on a Partially Observable Markov Decision Process (POMDP) is proposed, whose target is to maximize a reward function that reflects the suitability of the available spectrum blocks to the application requirements. The proposed strategy combines partial observations of the interference state in the different spectrum blocks together with a statistical characterization of the interference dynamics. Thanks to this feature, the performance comparison of the algorithm against different reference strategies reveals that it achieves a very similar performance than a strategy operating under full knowledge of the real interference state of all the spectrum blocks, while at the same time it has much less requirements in terms of measurement needs and associated signaling.