International Journal of Computer Science Issues

More than a traditional journal...

In the last decades, mobile communication services have progressed very rapidly, which demands wider spectrum band. Studies by Federal Communications Commission (FCC) show that much of fixed assigned spectra are not used efficiently. Such kind of spectrum scarcity can be overcome by a use of the cognitive radio (CR). It has the capability that allows the Secondary Users (SUs) to use the wireless licensed spectrum when it is not used by the Primary Users (PUs). In this paper, an Opportunistic Cognitive Medium Access Control (OC-MAC) protocol is proposed that helps the CR to use the spectrum efficiently whenever it is vacant. The proposed OC-MAC protocol increases the spectrum efficiency. Moreover, it also removes the traditional hidden terminal problem commonly faced by the CR. Interference between the PUs and SUs is removed by the use of Request to Send (RTS) and Clear to Send (CTS) packets.