Multimedia traffic transmission over Cognitive Radio TDMA networks under secondary collision errors

Cognitive Radio is an enabling technology for communication and channels sharing in multimedia and wireless networks. In this paper, we consider multimedia traffic transmission over shared Cognitive Radio (CR) networks using fountain codes. To share this CR infrastructure, we propose to make use of Time Division Multiple Access method based on the opportunistic spectrum sharing. Each Secondary User (SU) is assigned one time slot where he transmits with a certain probability. 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, the reasons for packet loss are twofold: Primary traffic interruptions and collisions between several SUs due to our specific time slot allocation. We use a redundancy-based model for link maintenance to compensate the spectrum resources loss caused by the primary traffic reclaims. Moreover, we setup up many Secondary User Links to minimize the collision effects in order to meet the QoS requirements for multimedia communication services. Numerical simulations, in view of the average Goodput, show that the system still exhibit good secondary traffic robustness despite of the presence of primary interferences and opportunistic transmission collisions.