Current wideband MILSATCOM infrastructure and the future of bandwidth availability

The military satellite communications (MILSATCOM) infrastructure is typically broken into three categories: wideband, protected, and narrowband. Wideband systems emphasize high capacity, protected systems prioritize anti-jam features and covertness, and narrowband systems emphasize support to the disadvantaged user by providing low data rate communications to small / mobile users. This paper focuses on the existing wideband MILSATCOM infrastructure (namely the Defense Satellite Communications System and Global Broadcast Service), because the architecture that exists is aging technology that lacks the ability to provide the required bandwidth to the warfighters without relying on commercial satellites. Bandwidth is limited and expensive to purchase, resulting in the DoD leasing transponders on commercial communications satellites - a solution that may not always be an option. This paper also illustrates various technologies and future programs currently being investigated by the Department of Defense (DoD) in order to augment and/or replace existing systems, and the resulting capability and benefits provided to the warfighter. These programs include the Wideband Global SATCOM (WGS) (previous known as Wideband Gapfiller Satellite System), and the Advanced Wideband System (AWS) / Transformational Satellite Communications System (TSAT). Both WGS and AWS/TSAT will significantly increase the bandwidth capacity of the wideband MILSATCOM architecture. These military initiatives take advantage of nascent technology such as IP router technology and laser cross-links to maximize performance. Finally, the paper describes several techniques to augment these MILSATCOM programs and increase their capacity and effectiveness, including: use of a network-style approach (vice point-to-point), combining space and terrestrial systems, use of near-space communication platforms (e.g. high-altitude UAVs or balloons), operating at higher frequencies, use of multiple satellites and re-use fr- equencies, and use of IP accelerators. These techniques increase the bandwidth capacity and improve its effectiveness by providing diversity, better quality of service via multiple relays, improved link performance via network architecture, and increase the amount of effective bandwidth available by including airborne platforms as additional communications relays.