Date Added: May 2010
In this paper, the authors explore the possibility of exploiting underutilized channels in the GSM bands, by means of secondary use of spectrum. The secondary (unlicensed) users are the nodes of an overlay cognitive ad-hoc network, which opportunistically transmits in data channels left unused by the primary (licensed) system. The focus is on the feasibility of the proposed approach, so that they consider a system level simulator based on a realistic GSM network deployed in the city of Bologna. In this context they propose a fuzzy-based approach to select the most appropriate frequency carrier for secondary usage, and they evaluate the impact that the operation of the secondary users has on the performances of the primary system.