Inter-Network Resource Sharing and Improving the Efficiency of Beyond 3G Systems

Today\´s wireless networks are characterized by a fixed spectrum allocation policy. Nevertheless, a large portion of the assigned portion is used sporadically and geographical variations in the utilization of assigned spectrum ranges from 15% to 85% with a high variance in time. The limited available spectrum and inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. This new paradigm is referred to as dynamic spectrum usage. In this paper, we show that we can improve the overall efficiency of the system by sharing different resources in the network between several operators. We use the term "resource" to not only account for spectrum sharing but also towers, base stations and time slots sharing. In our framework, we will use a physical layer cellular model with idealistic resource management, where we quantify the achievable sharing gains. We compare the performances for the non sharing case, the case where the base stations decide to share the resources as a "last resort", and also when the mobile stations always connect to the best base station (regardless of the operator). Finally, we analyze these gains in terms of quality of service, number of operators and different service classes.