An Adaptive Spectrum Assignment Algorithm in Cognitive Radio Network

Today’s wireless networks are characterized by a fixed spectrum assignment policy. On the other hand, a huge portion of the assigned spectrum is underutilized. But in contrast, rapid development of wireless communication technologies is seriously challenged by spectrum scarcity problem and lower spectrum utilization. Cognitive radio network (CRN), a revolutionary technology in wireless communication area, has been regarded as one of the most effective solutions to improve spectrum utilization by allowing secondary users (SUs) to opportunistically share unused spectrum bands with primary users (PUs). Secondary users (SUs) are required to vacate the channel when a primary user (PU) appears on the same licensed channel. This may cause interruptions in the secondary network transmissions. The paper presents a cluster based channel assignment scheme for CRNs which allocates available channels to most suitable SUs one by one. Also, the scheme handles dynamism in channel availability caused by presence of primary user on the channel allocated to some SU, in time efficient manner leading to enhanced spectrum utilization with fair allocation to all SUs.