Markovian primary traffics in Cognitive Radio networks

In this paper, we propose a solution to the multimedia transmission problem over Cognitive Radio networks in lossy environments. For a Cognitive Radio network where the spectrum is owned by Primary Users (PUs) that have a Markovian traffic, Secondary Users are allowed to share these spectral resources using the Time Division Multiple Access method based on the Opportunistic Spectrum Sharing. Each Secondary User (SU) is assigned one time slot where he usually transmits. The given model allows each SU to transmit in the remaining slots if he has data to transfer and has missed his own slot. Therefore, packets are not only lost by reason of Primary traffic interruptions, but also we consider losses caused by collisions between several SUs due to our specific time slot allocation. We use a duplication-based approach to setup up many Secondary User Links (SULs) in order to minimize the collision effects. Numerical simulations, in view of the Spectral Efficiency, show that the system still exhibit good secondary traffic robustness despite of the presence of primary interferences and secondary collisions.