1 This research work has been funded by the European Commission through IST Project EMILY IST-2000-26040 and the Spanish Government through CICYT project TIC2000-1041-C03-01. Abstract This paper shows the need to transmit extra assistance data in hybrid location systems. The proposal presented here uses the current network protocols in order to deliver these non-standardized assistance data in ...

The satellite communication data traffic is increasing dramatically over the coming years. High throughput multibeam satellite networks in Ka band are potentially able to accommodate the upcoming high data rate demands. However, there is only 500 MHz of exclusive band for download and the same amount for upload. This spectrum shortage impose a barrier in order to satisfy the increasing demands....

The Relationship between rain attenuation and depolarization at frequencies above 10GHz is useful for designing high-speed out-door wireless systems, such as satellite communication, millimeter FWA(Fixed Wireless Access) system and so on. Due to rapid growth of and strong demand for high speed communication, usage of millimeter wave bands in wireless system becomes in reality. The objective of ...

The increased interest in analog speech scrambling techniques are due to the increased visibility and publicity given to the vulnerability of communication systems to eavesdropping of unauthorized remote access (Gersho & Steele, 1984). In wireless communications, including High Frequency (H.F) and satellite communications, it is almost impossible to prevent unauthorized people from eavesdroppin...

As the complexity of telecommunication systems continues to rise, resulting from an ever increasing demand for new services and facilities from users, engineers are faced with more and more complex systems to design, so as to meet their requirements. Although this is true for all scientific fields, it is particularly important in telecommunications, namely for mobile satellite communication sys...

The present paper considers the problem of autonomous synchronization of attitudes in a swarm of spacecraft. Building upon our recent results on consensus on manifolds, we model the spacecraft as particles on SO(3) and drive these particles to a common point in SO(3). Unlike the Euler angle or quaternion descriptions, this model suffers no singularities nor double-points. Our approach is fully ...

Wireless communication is used in many different situations such as mobile telephony, radio and TV broadcasting, satellite communication, and military operations. For all these situations, a frequency assignment problem arises with application of specific characteristics. Different modelling ideas for every problem features, have been developed such as the handling of interference among radio s...

The International Telecommunications Satellite Organization (INTELSAT), the 109-nation cooperative responsible for the vast majority of international satellite service, was recently presented with what may be its greatest challenge since its inception over twenty years ago. The consortium, hailed by many as a model among international organizations, faces possible competition from five American...