Low earth orbit (LEO) satellite constellations could play an important role in future mobile communication networks due to their characteristics, such as global coverage and low propagation delays. However, because of the non-stationarity of the satellites, a call may be subjected to handovers, which can be cell or satellite handovers. Quite many techniques have been proposed in the literature ...

This work is aimed at investigating the use of Multi Carrier CDMA (MC-CDMA) techniques in variable bitrate transmission over low-earth-orbit (LEO) satellite channels by means of realistic simulations. It is known by literature that MC-CDMA techniques are much more resilient with respect to multi-user interference effects in multipath fading channels than single-carrier DS/CDMA ones. Moreover, M...

The problem of handoffs in cellular networks is compounded in a low earth orbit (LEO) satellite-based cellular network due to the relative motion of the satellites with respect to a stationary observer on earth. Typically, the velocity of motion of mobiles can be ignored when compared to the very high velocity of the footprints of satellites. We exploit this property of LEO satellite systems an...

This paper evaluates the proposed implementation of short length low density parity check (LDPC) codes within the telemetry space protocol. Due to the varying orbital patterns of low earth orbit (LEO) satellites, limited communication time windows need to be optimised to maximise data throughput. Most popular connection oriented protocols focus on correcting congestion related link errors, but ...

Low-Earth Orbit (LEO) satellite systems are intended to have an important part of the future generation of mobile telecommunication systems. They aim to provide di erent services to various populations of users. Each class of users requires a certain Quality of Service (QoS) and thus a given part of the shared channel resource. In this paper, LEO satellite systems based on an earthxed cell conc...

VoIP PERFORMANCE IN NGEO SATELLITE IP NETWORKS WITH ON-BOARD PROCESSING CAPABILITY In this thesis study, an adaptive routing policy utilizing the real-time network information of a two-layered satellite network is introduced. In a satellite network, depending on the requirements and properties of services provided, various kinds of satellites from different orbits can be employed. Geostationary...

Low-Earth Orbit (LEO) satellite systems are intended to have an important part of the future generation of mobile telecommunication systems. They aim to provide diierent services to various populations of users. Each class of users requires a certain Quality of Service (QoS) and thus a given part of the shared channel resource. In this paper, LEO satellite systems based on an earth-xed cell con...

This paper focuses on interference suppression aspects for DS/CDMA (Direct Sequence / Code Division Multiple Access) LEO (Low Earth Orbit) satellite communication systems. The interference of other users represents a serious problem for LEO satellite CDMA systems. The application of interference suppression systems is a promising approach to mitigate the multiuser problem. With the concentratio...

This paper investigates two strategies that exploit low-thrust propulsion and natural effects for the complete de-orbiting of spacecraft from a Low Earth Orbit (LEO). The first strategy aims to actively lower perigee altitude by achieve passive drag-induced re-entry. second move reach specific condition can provoke orbital decay means coupled effect perturbations. For each strategy, sub-time-op...

We review research on geomagnetic pulsations carried out using magnetic field measurements from the CHAMP lowEarth-orbit (LEO) satellite and ground-based stations in South Africa and Hungary. The high quality magnetic field measurements from CHAMP made it possible to extract and clearly resolve Pi2 and Pc3 pulsations in LEO satellite data. Our analyses for nighttime Pi2 pulsations are indicativ...