The AI project aims to achieve effective and fair bandwidth usage of its relatively narrow satellite links by all the partners in this project and the best possible end-to-end communication quality under limited resources. It is difficult to realize them as the operation of it is shared by all the partners with heterogeneous traffic demands and policies, as the network includes many traffic eng...

This paper developes crosslink routing strategies for the Mobile Satellite System Iridium [1,3,6,8]. Motorola’s Iridium satellite constellation, based on the orbit design of Adams and Rider [2] is to provide mobile satellite service for hand-held personal telephones. The Iridium system will have 66 satellites in 6 orbital planes at an altitude of h = 780 km and a minimum elevation angle of θ = ...

The exploitation of fluctuating channel conditions in link adaption techniques for unicast transmission has been shown to provide large system capacity gains. However, the problem of choosing transmission rates for multicast transmission has not been thoroughly investigated. In this paper, we investigate multicast adaptive techniques for reliable data delivery in GEO satellite networks. An opti...

We present the results of the performance evaluation of polarization-time coding and soft interference cancellation in multi-beam satellite systems a ected by co-channel interference in realistic setups. The standard of Broadband Global Area Network service (BGAN) has been considered as reference for the physical layer and realistic interference and channel models have been adopted. The work ha...

This paper presents a means for optimizing the data throughput for low earth orbit (LEO) satellites by implementing a mission specific error control strategy. Due to limited connectivity and very limited overflight time exposure offered by LEO satellites, it is imperative to volumetrically optimize the data throughput. With power limitations on the space segment and remote groundstations, hardw...

Aiming at the requirement of the autonomous time synchronization in BeiDou Navigation Satellite System (BDS), an algorithm for inter-satellite autonomous time synchronization and ranging is proposed. Based on the establishment of the inter-satellite link length model of the BDS, a series of simulation has been carried out through the use of STK (Satellite Tool Kit), which includes the simulatio...

Satellite services (e.g. Internet-over-Satellite or GPS) are getting more and more important in our lives, whereby the operational area is still growing. To guarantee those services, reliable simulation tools are necessary to scale and validate actual and future satellite systems. Therefore, this paper gives an overview about development, functionalities and benefit of a satellite simulation fr...

Wideband direct-sequence (DS)-code-division multiple-access (CDMA) is a strong candidate for both terrestrial and satellite components of UMTS. The forward-link capacity of a satellite DS-CDMA system with a conventional matched filter (MF) receiver is limited by interference from adjacent beams and possibly overlapping beams from multiple satellites. In this paper, we study the performance of t...

Japan’s Quasi-Zenith Satellite System (QZSS) is scheduled for launching in 2010. We have been conducting research on the remote synchronization system for the onboard crystal oscillator (RESSOX), which does not require onboard atomic clocks, for the QZSS since 2003. RESSOX reduces overall cost and satellite power consumption, as well as onboard weight and volume, and is expected to have a longe...

Recently, earth observation system by using satellite network have attracted much attention due to their wide coverage and disaster resistance. Although the system is useful for collecting various data, which have an affect on a natural disaster, ecology and so forth, earth observation satellite hardly send the collected observation data to the ground station. This is because that the earth obs...