Low Earth Orbit Satellite Networks can augment terrestrial wireless networks to provide global broadband services to users regardless of the users’ locations. Delivering QoS guarantees to the users of LEO satellite networks is complicated since footprints of LEO satellites move as the satellites traverse their orbits, and thus, causing frequent user handovers between the satellites. Traffic on ...

If an attempt is made to produce an artificial aurora by ejecting a beam of electrons from a satellite, the experiment will be jeopardized if the satellite potential becomes so high as to prevent the escape of the beam electrons. The buildup of potential depends on the current collection properties of the satellite. The theoretical problem considered is that of the collection of electrons by a ...

In high-speed satellite-to-ground laser communications, it has been shown that the Markov-based erasure channel model is well suited for the downlink experiment results. In that model, since the average erasure rate is relatively high, a low-rate error correction code is needed. In this paper, we focus on the application of low rate systematic Luby transform (SLT) code and show that the perform...

In this paper, we implement the robust demodulator for mobile broadband satellite internet access systems. Especially, in order to achieve the good synchronization under very low SNR, a large frequency offset, and Doppler frequency offset with constraints of mobile satellite communication, we introduce the efficient carrier freq. offset estimating algorithm and the carrier phase estimating algo...

Satellite constellations ooer interesting perspectives for Internet traac routing, since they beneet from a worldwide coverage and do not have the main drawback of geosynchronous satellites : propagation delay. However, because of their low altitude, LEO satellites are in constant motion and exhibit speciic issues for routing. This article presents a general architecture applicable to the integ...

BACKGROUND Air pollution may be related to adverse birth outcomes. Exposure information from land-based monitoring stations often suffers from limited spatial coverage. Satellite data offer an alternative data source for exposure assessment. METHODS We used birth certificate data for births in Connecticut and Massachusetts, United States (2000-2006). Gestational exposure to PM2.5 was estimate...

This master thesis presents a preliminary investigation into the impact of TCP’s advertised receive buffer size and timer granularity on TCP performance over an erroneous link in a low earth orbit (LEO) satellite environment. Conducted simulations include over 200 different combinations of TCP flavor, advertised receive buffer size, timer granularity, and bit error rates. Results show that TCP ...

To reduce the sampling rate in global navigation satellite system (GNSS)-radio occultation receivers, it is essential to establish a suitable estimation of Doppler frequency from the received signal in the satellite onboard receiver. This receiver is usually located on low earth orbit satellite and receives GNSS satellites signal in the occultation situation. The occurred Doppler on the signal ...

SUMMARY We propose a novel channel model of satellite-to-ground optical transmission to achieve a global-scale high-capacity communication network. In addition, we compose an effective channel coding scheme based on low-density generator matrix (LDGM) code suitable for that channel. Because the first successful optical satellite communication demonstrations are quite recent, no practical channe...

Routing in Low-earth-orbit (LEO) satellite system involves the choice of inter-satellite links (ISLs) that connects two home satellites of the mobile terminals. We use a mesh model to formulate the LEO system and proposed 4 mesh-based algorithms. The objective is to minimize the new call blocking probability and the forced termination probability. Also, due to the dynamic topology of the LEO sy...