Performance Evaluation of Spectrum Sharing Algorithms in Single and Multi Operator Scenarios

The increasing demand of indoor broadband access encourages the diffusion of the "home base stations", known as femtocells. Their self installation nature envisages interference problems due to a possible overload of local femtocell installations in the same area. To reduce the interference among femtocells we propose and analyze the performance of a dynamic frequency selection strategy, according to which each femtocell is able to select one of the possible frequencies available from all the operators in order to experience the best Signal-to-Interference Ratio (SIR). We assume that mobile operators share their requency bands allowing femtocells subscribed to a certain operator to exploit the frequency resources of other operators. In this paper we evaluate the performance in terms of allowed number of active femtocells per operator when the channels available from operators increase. It is observed that the application of the proposed Dynamic Frequency Selection (DFS) algorithm with band sharing allows single operator to significantly improve the number of active femtocells deployed in the area with respect to the non band sharing case, i.e. a Spectrum Sharing Gain is achieved.