It is well known that satellite communications systems are effective and essential communication infrastructure for disaster relief. NICT sent researchers to Tsunami stricken area in March right after the Great East Japan Earthquake and provided broadband satellite communications link to support rescue activities. Through this experience, we learned many kinds of requirements of communications ...

Studies have shown that packet reordering is common, especially in satellite networks where there are link level retransmissions and multipath routing. Moreover, traditional satellite networks exhibit high corruption rates causing packet losses. Reordering and corruption of packets decrease the TCP performance of a network, mainly because it leads to overestimation of the congestion in the netw...

Satellite communication systems are the means of realizing a global broadband integrated services digital network. Due to the statistical nature of the integrated services traac, the resulting rate uctuations and burstiness render congestion control a complicated, yet indispensable function. The long propagation delay of the earth-satellite link further imposes severe demands and constraints on...

This paper presents a mechanism for dynamic rate control of satellite integrated services, based on a cross-layer approach, utilising link quality feedback from the satellite terminals. The mechanism, namely, satellite resource management system (SRMS) relies on the adaptive coding and modulation (ACM) capabilities of DVB-S2 in order to perform real-time adjustments on the physical, network and...

The results of a transmission experiment of MPEG-2 coded video data over a satellite link affected by noise are presented. The goal was to investigate under which conditions this type of transmission is economically feasible. The scalability feature of the MPEG-2 encoder was used to produce different bitstreams of the same video sequence. We wanted to verify the best combinations among video an...

Existing satellite systems used QPSK modulation with concatenated Convolutional and Reed-Solomon error correction codes as per the DVB standard. In addition, the RF links are run using fixed margins with the size of the margin dependent upon the maximum rain attenuation predicted for the service area. One way to increase the system data throughput is to manage each user terminal separately and ...

We investigate a topological design and routing problem for Low-Earth Orbit (LEO) satellite communication networks where each satellite can have a limited number of direct inter-satellite links (ISL's) to a subset of satellites within its line-of-sight. First, we model LEO satellite network as a FSA (Finite State Automaton) using satellite constellation information. Second, we solve a combined ...

The use of more and more high frequency bands is presently one of the major trends in the satellite communications field. Several important advantages can be achieved by increasing frequency against a sensible impact with atmospheric effects, in particular with the heavy fading induced by rain precipitations. In the last few years, several methods based on adaptive techniques to counteract the ...

Small satellite technology has opened a new era in aerospace engineering by decreasing space mission costs, without greatly reducing the performance. The concept of formation flying using small satellites is becoming popular because of their potential to perform coordinated measurements of remote sensing space missions. The current state of art in satellite communications is a one hop link betw...

For future commercial broad-band data satellite networks, satellite network topology, link capacity, and routing have major impacts on the cost of the network and the amount of revenue the network can generate. In this thesis, we establish a mathematical framework, using two-stage stochastic programming, to assist network designers in selecting the most cost-effective network topology for data ...