Personal communications via low Earth orbit satellite communication networks

With the emergence of cellular radio technology, there has been a renewal of interest in low-Earth orbit (LEO) satellite communication networks. Interest in these type of systems is fuelled by reduced propagation delays compared to those experienced by geostationary satellites as well as the benefits associated with mobile and tetherless communications. LEO systems are presently being proposed to provide global communications for both voice and data applications. These systems are being designed to provide communications to areas of the world where either public telephone systems do not exist or cannot be provided due to terrain constraints. This paper examines the effects of packet-switched low-Earth orbit satellite systems as a medium for wireless communications. An overview of LEO systems is provided, as well as critical issues associated with the implementation of such a system. The benefits as well as the detriments to the implementation of LEO systems over other types of communication networks are addressed. To illustrate the nature of LEO communications, six representative constellations, varying in size from 36 to 77 satellites and residing at orbital altitudes ranging from 765 to 1549 kilometers, are examined.