In this subsection, spectrum efficiency metrics for both broadcast and point-to-point satellite communications systems have been proposed and additional efficiency considerations have been identified and discussed. Non-communications systems and applications like navigation services (e.g., global positioning systems), meteorological (e.g., weather satellites), earth observation (e.g. ocean and earth temperature and humidity observation), and remote sensing (e.g., imaging systems) have been discussed, and given their unique nature, an individualistic approach to achieving spectrum efficiency has been proposed. Finally several areas have been identified where additional academic research would be valuable to further refine these metrics and associated considerations.
Spectrum Efficiency Metrics for Terrestrial Systems
To an even greater degree than the satellite systems case discussed in Section IV, terrestrial systems encompass an extremely large variety of services including non-communications services such as radar systems. For the reasons explained earlier, the Working Group was unable to identify or evaluate suitable spectrum efficiency metrics for radar systems for this version of the White Paper. The Working Group was, however, able to address spectrum efficient metrics for the following classes of systems: Broadcast Systems, Personal Communications Systems, Point-to-Point Systems, and Hybrid Terrestrial Systems – Public Safety / Utility. Each of these four classes of systems is discussed in the subsections that follow.
The working group recognized that the Commerce Spectrum Management Advisory Committee (CSMAC) had reported definitive findings for spectrum efficiency for the systems discussed here. Therefore, the material below closely follows that work and some sections of the text have been taken directly from the CSMAC report.