Opportunistic Spectrum Multichannel OFDMA

Opportunistic Spectrum Access (OSA) is being seriously considered for the future spectrum needs. In this paper we propose a simple and effective multichannel multiple access technique for OSA networks. In our design users of an OSA network must contact the OSA Base Station to gain access to the radio resources. In an OSA environment each of the channels can be arbitrarily occupied by the Primary Users (PUs) of the specific band. Thus the OSA nodes should cause least interference to the PUs while exploiting the voids in the PU usage. We analyze the OSA network where many OSA nodes would be competing amongst themselves and with the PU, using fast retrials. We also propose mechanisms to minimize the probability of collisions and interference caused to the PUs, while maximizing the throughput of the OSA network.