The virtual genus of a virtual satellite link is equal to that of its companion.

Inter-satellite links (ISLs) have become an important technology for developing global navigation satellite systems (GNSSs). Due to platform restrictions, the number of ISLs is limited, how optimize ISL assignment a crucial challenge. A mathematical optimization model formulated that accommodates both ranging and communication requirements. We prove problem performance non-deterministic polynom...

Satellite communications are destined to play an important role in future telecommunications infrastructure, thus the increasing interest in transporting Internet traac over satellite links. Many studies have shown that TCP has a poor performance in the context of satellite communications. This is due to many factors inherent to satellite communications and for which TCP originally designed for...

This article describes the use of Software Defined Radio over the Software Controlled Radio in a cooperative wireless network in an OFDM based downlink scenario. The article argues that although the state of the art of SCR is considered superior with respect to implementation factors such as complexity, cost and efficiency, the SDR offers a degree of flexibility together with the use of coopera...

This paper presents a graph-based spatial model which can serve as a reference for guiding pedestrians inside buildings. We describe a systematic approach to construct the model from geometric data. In excess of the well-known topological relations, the model accounts for two important aspects of pedestrian navigation: firstly, visibility within spatial areas and, secondly, generating route des...

A hybrid switching node structure with light and microwave links is proposed, which is applicable to the future data relay satellite systems, aiming at the development trend of coexistence of lightlink and microwave-link in the future. An experimental system for the light and microwave hybrid switching node based on wavelength selective optical switches (WSS) and optical transceiver modules, is...

The demand for Internet bandwidth has grown rapidly in the past few years A new generation of broadband satellite constellations promise to provide high speed Internet connectivity to areas not served by optical ber cable or other high speed terrestrial connections However using satellite links to supply high bandwidth has been di cult due to problems with ine cient performance of the Internet ...

When a robot arm(s) conducts some tasks on a satellite, the satellite attitude stability is necessary against the robot arm's motion to maintain the communication link and to generate electrical power from the solar panel(s). However the reaction from the robot arm is much stronger than the natural environmental disturbance torque that the traditional satellite attitude control system cares. Na...

Optical wireless communication has undeniably revolutionized the satellite communication systems for use in the coming future. These OWC systems have become popular due to their high data rate performance in different weather conditions. This paper demonstrates a comparative analysis of RZ (Return to zero), NRZ (Non-return to zero) and Gaussian pulse generation methods by varying the levels of ...

• Great Duck Island [SMP04]. Szewczyk et al. have used two sensor patches, gateways, base station and satellite WAN link for their experiments. A gateway node interfaces a sensor patch to the base station and consists of a mote with 14dBi high gain yagi antenna (point-to-point, directional). The base station collects the data from the sensor patches in the database and makes the data available ...