Performance Evaluation of a Hybrid Satellite Network Based on High-Altitude-Platforms

The proposed system architecture is quickly configurable and suitable for disaster aid or war scenarios, where the rapid event changes must be monitored at a higher rate than the one offered by common Earth observation systems. Moreover, high altitude platforms (HAPs) represent an easy and affordable solution for providing Internet access in absence of infrastructure. This system is based on several HAPs located on different sites within the same GEO visibility area. Each HAP is equipped with an optical payload in order to establish an optical link to a satellite and a WiMAX interface to the ground. The satellite acts as the optical transponder. The advantage of these platforms is that HAPs are easily accessible from Earth for their maintenance. High transmission performance in the optical links can be achieved by systems operating at 1550 nm wavelength, where the Erbium doped fiber amplifier (EDFA) can improve the optical signal-to-noise ratio (OSNR) on the receiver end, and phase modulation schemes (i.e. differential phase shift keying -DPSK) can be used jointly with error correction codes so to ensure reliable high performance transmission. The aim of this paper is to define the operative conditions that guarantee a high effectiveness in the band exploiting, as well as in power consumption.