**3.3 Other applications**

Other applications of MDP have been found within the framework of cognitive radio. In Hoang et. al. (2010), authors propose an algorithm based on finite-horizon MDP to schedule the duration of spectrum sensing periods and data transmission periods at the cognitive users aiming to improve their throughput. Berthold et. al. (2008) formulate the spectral resource detection problem as an MDP allowing the cognitive users to select the frequency bands with the most available resources. Galindo-Serrano and Giupponi (2010) deals with the problem of aggregated interference generated by multiple cognitive radios at the receivers of primary (licensed) users. The problem is formulated as a POMDP and it is solved heuristically by means of an approximated dynamic programming method known as distributed Q-learning.

In this paper we highlight another application of MDP: dynamic trading of spectrum bands. While this issue has been typically addressed with a game-theoretic approach, we explore the use of MDP and CMDP formulations to balance benefit and grade of service for primary users in a centralized spectrum access framework.
