Adaptive small cell emission masks(SCEMs) as a licensing scheme in the 3.5GHz band

This paper focuses on a solution for a spectrum access system that can be deployed in the 3.5 GHz band to enable sharing of these bands between existing incumbents and new small cell systems. The FCC envisages some kind of dynamic data base as a means of supporting this sharing. In this paper we recommend that the database should support the use of adaptive spectrum masks, defined at the cell level, to control the emissions of the systems sharing the bands. The severity of the mask is context dependent and hence the least restrictive mask rather than one that represents a worst case scenario is used. Calculating the least restrictive spectrum mask in a context dependent manner involves examining an infinite number of potential scenarios. Our solution makes use of a pixelated database which results in large but finite no of possibilities and therefore converts the problem to a tractable one. A library of masks, each one corresponding to a specific scenario, is then stored in theh database. The fact that users must register with the database to access spectrum means it is possible to determine the distribution and density of users (i.e. the context). and retrieve the best mask. This will allow for far more efficient use of the spectrum then in a traditional system while still guaranteeing a certain QoS for the users.