X-band, Ka-band, and future Milsatcom requirements: an outing in trade space

The current US wideband Milsatcom system, DSCS, uses X-band to provide service to all types of wideband users. However, in the near future, the community will have both X-band and Ka-band frequencies available. The question arises, which frequencies are best for which missions? This paper presents a quick-look analysis of two alternative approaches, relying on reasonable and consistent, if somewhat arbitrary, assumptions. In the first, tactical services are supported by a transponded X-band payload. In the second, we use Ka-band to support the tactical users, and argue that this payload should be processed. In both cases the frequency not chosen for the tactical mission is assigned to primarily support infrastructure users. This paper concludes that for comparable levels of coverage, connectivity, link availability, and radiated satellite power, the achievable tactical capacity of each satellite could be several times higher using the processed Ka-band approach