Spectrum sharing between the Mobile Service and existing fixed and fixed satellite services in the 3.6?3.8 GHz band

European administrations are currently in the process of defining national spectrum sharing frameworks to enable coexistence between new entrant Mobile/Fixed Communication Networks (MFCNs) and the incumbent Fixed Satellite Service (FSS) downlink and Fixed Service (FS) in the 3.6-3.8 GHz band. In this paper we propose a methodology for establishing such frameworks whereby administrations define criteria for the protection of the incumbent users in the form of maximum permitted interference levels at the input of the FSS and FS receivers. These limits are then used to calculate either geographic exclusion zones or the maximum permitted radiated powers of MFCN base stations, so as to avoid harmful interference to the FSS and FS. The above calculations can be performed by the MFCN operators, the administration, or a third party. We also set out a number of novel options to account for interference aggregation and the partitioning of the interference budget across multiple MFCN base stations and operators. There is always a trade-off between the simplicity of a spectrum sharing framework and spectrum sharing efficiency. The proposed methodology provides the flexibility for administrations to exploit this trade-off according to their specific national circumstances.