Relative performance of mobile networks in the Ku, commercial Ka and government Ka bands

In the past 10 years mobile satellite networks have gained a strong foothold in the commercial Ku-band and now attention is turning to mobile networks in the commercial and government Ka-bands. Examples of new Ka-band commercial systems abound (Inmarsat-5, ViaSat-1 and Jupiter-1) and WGS is just opening up the government Ka-band in a big way. Land, sea, and aero communications-on-the-move (COTM) applications are being proposed and developed in each of these bands. While these systems are new and highly anticipated, it does not naturally follow that one band or type of system is better than another for all purposes. For example, much of the increased directivity of Ka-band relative to Ku-band is offset by more restrictive off-axis EIRP spectral densities (ESD) limits in the commercial Ka-band These limits are much less restrictive in the government Ka-band Similarly, while Ka-band rain fade is a critical issue for land and sea mobile terminals, it does not pose any difficulty for aeronautical terminals, which normally operate above the weather. Each band and system has its strengths and limitations. This paper compares the relative merits of each of these bands and the types of systems being developed for different mobile applications. We examine the performance and coverage of similar size mobile terminals in each band, paying close attention to the differences in regulatory limitations and satellite performance in each band Finally, we draw conclusions about which bands and types of systems might best fit the different mobile applications.