Dynamic spectrum access: A Markovian approach to predict profits of primary user

Dynamic spectrum access is an effective approach to improve the spectrum utilization. When primary user (PU) leases its spectrum to secondary users (SU), the spectrum efficiency can be enhanced, however, PU might be interfered by the co-existence of SU. This paper considers the situation that PU is willing to coexist with SU once it is paid and its Signal to Interference-plus-Noise Ratio (SINR) is guaranteed. The lease fee could be charged by time or data flow. A continuous time Markov chain (CTMC) is built to measure PU´s benefits and potential losses. In computing the steady probabilities of the CTMC, the augmented matrix is devised. The error detection is also considered in the CTMC and a method is proposed to choose the decision threshold which can ensure the fair contention among the SUs. Simulations show the expected profits of PU and the fair competition among SUs. A specific application is considered in the simulation, which can help decide whether the cooperation between SUs in a relay channel is profitable.