Spectrum sharing research in CTL develops the requirements and test methods necessary for Federal/commercial spectrum sharing. The 3.5 GHz band is one of the first examples of such sharing, where the Citizens Broadband Radio Service will share spectrum with Federal incumbents on a tiered (prioritized) basis.
Areas of research include the detection requirements of sensors that will alert commercial systems to incumbent signals so that the latter can be protected. This research involves applying models of deployment, propagation, and aggregate interference to predict signal levels, as well as evaluating signal processing algorithms for blind radar detection in the presence of co-channel commercial signals.
In addition, CTL is developing test methods to ensure that commercial systems deployed in shared bands function as required. These tests will verify that Spectrum Access Systems—the systems that coordinate commercial access to the shared band—and the sensor networks they rely on, can dynamically mitigate interference to federal and other incumbents when necessary.
The results of this research form the basis for contributions and reference implementations to spectrum sharing standards organizations. They also appear in the form of technical publications (see selected list below).