Efficient spectrum sharing with avoiding spatial fragmentation of white space

This letter proposes an efficient spectrum sharing by using a smart channel selection with considering the spatial shape of white space (WS) for cognitive radio systems. Here, we consider the environment in which secondary users (SUs) share the same spectrum with multiple channels. In such situation, the assignment channel avoiding spatial fragmentation is important because other SUs can easily access to remaining WS. In this paper, we utilize a perimeter to area ratio of WS for channel assignment as a criterion for evaluating value of remaining WS. We confirm the effectiveness of the proposed spectrum sharing method by using computer simulations.