Prospective Performance of LEO Satellite Systems Employing Spread-Spectrum Techniques

In this paper, we discuss on two important issues through the realization of global personal communication networks with low earth orbital (LEO) satellites. The first issue is the selection of an effective multiple access scheme which can utilize the limited spectrum allocated to these systems. In this way, we focus on the schemes based on spread spectrum techniques and explain their unique characteristics. The other issue is partitioning of footprint of satellites into smaller cells in order to improve the capacity of the system. This latter issue has been considered in satellite systems of other orbit altitudes such as geostationary orbit and also in terrestrial cellular systems, and recently, in the proposals of LEO satellite systems it has been explained as an essential requirement. We explain the issue when spread spectrum is used and discussed on the factors which should be considered in the case of LEO satellite systems in order to expect similar capacity improvement.