<title>Satellite communications network architecture which alleviates the need for intersatellite links</title>

Abstract

Intersatellite crosslinks (between satellites in different orbits) are difficult to implement and manage in nongeostationary orbital constellations. It is possible to alleviate the need for intersatellite crosslinks and yet provide global coverage at a propagation delay of no more than 125 milliseconds. The satellite orbit architecture used in this paper is suitable for future satellite networks applications, such as interactive multimedia, video conferencing, image transfer, audio, voice, and store-and-forward services. The Earth's surface has been divided into spherical hexagonal areas with some overlapping. The key parameters that define the satellite network architecture have been derived in this paper. These parameters include the Earth's central angle, number of satellites per orbit, number of orbits, cell size, maximum propagation delays, and the average number of satellites available for a user (as a function of distance from the Equator). Each of these parameters are plotted vs. satellite altitude and elevation angle. The propagation delay is not sensitive to changes in elevation angle, but sensitive to orbital altitude. The satellite orbit architecture presented herein is currently under investigation for networking aspects and response to traffic loading.