Optimal and Low-Complexity Algorithms for Dynamic Spectrum Access in Centralized Cognitive Radio Networks With Fading Channels
In this paper, the authors develop a centralized spectrum sensing and Dynamic Spectrum Access (DSA) scheme for Secondary Users (SUs) in a Cognitive Radio (CR) network. Assuming that the primary channel occupancy follows a Markovian evolution, the channel sensing problem is modeled as a Partially Observable Markov Decision Process (POMDP). They assume that each SU can sense only one channel at a time by using energy detection, and the sensing outcomes are then reported to a central unit, called the Secondary System Decision Center (SSDC), that determines the channel sensing/accessing policies. They derive both the optimal channel assignment policy for secondary users to sense the primary channels, and the optimal channel access rule.