Satellite Communications

SATMED: Legal Aspects of the Physical Layer of Satellite-Telemedicine

by Stephen Rooke

Significant disparities exist between the availability of physicians and health care specialists in urban and rural... more Significant disparities exist between the availability of physicians and health care specialists in urban and rural areas, particularly in developing countries. For example, the concentration of medical specialists in Nairobi, Kenya, is 147 times higher than in Kilifi, a relatively large, but rural region. Emerging telemedicine technologies would enable doctors located in urban areas and elsewhere around the globe to serve rural patients. However, the limited availability of telecommunications infrastructure and technology necessary for telemedicine in rural areas inhibits the deployment of such health care applications. For example, in Namtumbo, Tanzania, a region with over 190,000 people, there are no doctors and none of the medical facilities have access to any type of telephone connection. Only twenty percent of Tanzania's health districts are connected by landline telephone.

Satellites' ability to bridge gaps in telecommunications infrastructure gives them a unique capacity to also bridge the urbal-rural health care divide by making telemedicine applications available to rural patients and medical professionals worldwide. Unfortunately, international law provides an expansive grant of national sovereignty over electromagnetic spectrum that supersedes state obligations to provide access to health care. As a result, the physical equipment necessary to provide telemedicine services to rural patients is subject to national regulatory regimes that prevent the widespread and cost-effective availability of life-saving technology.

This paper identifies the body of international law governing satellite-telemedicine including outer space law; conventions governing economic, social and cultural rights and the right to health care; and international telecommunications law including the ITU Constitution, Tampere Convention, and the Global Mobile Personal Communication by Satellite Memorandum of Understanding. It then concludes that an additional international undertaking to eliminate national barriers to entry for satellite-telemedicine technology is necessary.

Improving performance of Map Updates through Satellite Communications in Vehicular Networks

by Darwin Astudillo

In this paper, we propose to extend the WAVE Architecture with satellite, WiFi and cellular technologies. Many... more In this paper, we propose to extend the WAVE Architecture with satellite, WiFi and cellular technologies. Many applications can be considered in vehicular networks which can be provided through one or several communication systems. In this paper, the map update application has been considered over different technologies. Simulations were run using NS3 simulator to compare the behavior of files downloads with 802.11p and with other technologies. The aim is to optimize the necessary amount of resource, and to determine the best combination of technologies to download maps.

Space Assets for Demining Assistance

by Michiel Kruijff

Authors

Dr. Michiel Kruijff
European Space Agency (ESA)

Dr. Daniel Eriksson
Geneva International Center for Humanitarian Demining

Dr. Thomas Bouvet
European Space Agency (ESA)

Mr. Alexander Griffiths
Swiss Foundation for Mine Action (FSD)

Mr. Matthew Craig
Cranfield University

Prof. Hichem Sahli
Vrije Universiteit Brussel

Mr. Fernando Valcarce González-Rosón
INSA S.A.

Mr. Philippe Willekens
International Astronautical Federation

Prof. Amnon Ginati
European Space Agency (ESA)

Populations emerging from armed conflicts often remain threatened by landmines and Explosive Remnants of War. The... more Populations emerging from armed conflicts often remain threatened by landmines and Explosive Remnants of War. The international Mine Action community is concerned with the relief of this threat. The Space Assets for Demining Assistance (SADA) undertaking is a set of projects that aims at developing new services to improve the socio-economic impact of mine action activities, primarily focused on the release of land thought to be contaminated, a process described as Land Release. SADA was originally initiated by the International Astronautical Federation (IAF). It is now being implemented under the Integrated Applications Promotion (IAP) programme of the European Space Agency (ESA).
Land Release in Mine Action is the process whereby the demining community identifies, surveys and prioritizes suspected hazardous areas for more detailed investigation, which eventually results in the clearance of landmines and other explosives, thereby releasing land to the local population. SADA has a broad scope, covering activities such as planning (risk and impact analysis, prioritization, resource management), field operations and reporting.
SADA services are developed in two phases: feasibility studies followed by demonstration projects. Three parallel feasibility studies are currently ongoing. They aim at defining an integrated set of space enabled services to support the Land Release process in Mine Action, and at analysing their added value, viability and sustainability. The needs of the Mine Action sector have been assessed and the potential contribution of space assets has been identified. Support services are now being designed. To test their fieldability, proofs of concept involving mine action end users in various operational field settings are also under preparation by each of the study team. The economic viability will then be assessed.
Whenever relevant and cost effective, SADA aims at integrating Earth Observation data, GNSS navigation and SatCom technologies with existing Mine Action tools and procedures, as well as with novel aerial survey technologies. Such conformity with existing user processes, as well as available budgets and appropriateness of technology based solutions given the field level operational setting are important conditions for success. The studies have already demonstrated that Earth Observation data, Satellite Communication and Navigation indeed provide added value in Mine Action activities. Such added value for example includes the benefits of easy and sustained access to Earth Observation data that can satisfy the ubiquitous needs for general purpose mapping, as well as the value of data fusion algorithms which can be applied to relevant datasets to quantify risks and socio-economic impact for prioritization and planning purposes in order to justify land release. The environment of a hazardous area can also be characterized to support the land release process including detailed survey and clearance. Satellite Communication can help to provide relevant data to remote locations and in some cases can help to integrate field data and reporting with national or international databases. Finally, Satellite Navigation can support more precise non-technical surveys as well as aerial observation with small planes or hand-launched UAV’s.
To ensure the activity is genuinely user driven, the Geneva International Centre for Humanitarian Demining (GICHD) plays an important role as ESA’s external advisor. ESA is furthermore supported by a representative field operator, the Swiss Foundation of Mine Action (FSD), providing ESA with a direct connection to the field level end users. Specifically FSD has provided a shared user needs baseline to the three study teams. To ensure solutions meet with end user requirements, the study teams themselves include Mine Action representatives and interact closely with their pre-existing and newly established contacts within the Mine Action community.

Intelligent Railways via Integrated Satellite Services (IRISS)

by Michiel Kruijff

M. Kruijff (ESA), M. Dumville & M. Hutchinson (NSL), A. Ginati (ESA)

Train passengers and authorities demand trains’ timeliness, comfort, safety and energy efficiency. Train fleets, over... more Train passengers and authorities demand trains’ timeliness, comfort, safety and energy efficiency. Train fleets, over their multiple-decade lifetimes, will therefore typically undergo various modernizations, in order to improve fleet monitoring and management. It is then advantageous if additional equipment is highly integrated due to lack of on-train space. The IRISS project (Intelligent Railways via Integrated Satellite Services) proposes such an integrated service. It provides Train Operating Companies with essentially uninterrupted monitoring of train stock based on terrestrial and satellite communications, satellite navigation and conventional train metering. IRISS is a feasibility study initiated by the European Space Agency’s Integrated Applications Programme.

The involved user, East Midlands Trains (EMT, a UK Train Operating Company), has expressed the need for affordable and continuous tracking of their trains, as well as data communication between their control center and rolling stock. Information to be exchanged are e.g. messages & alerts, train location, diagnostic data, and camera footage (CCTV), both in real-time (to reduce service interruptions) and historical (e.g. to resolve disputes and optimize energy efficiency and maintenance). IRISS has investigated whether space assets can add value where conventional technologies face limitations. For example the existing ‘balise’ train location system provides low accuracy, while backcountry routes may still have poor communications coverage by terrestrial networks.
Nottingham Scientific Ltd. has defined a service architecture centered around the TITAN on-board unit that integrates satellite navigation (GPS, EGNOS, GLONASS), with satellite and terrestrial communication and that is fed by on-train sensors and CCTV. The control center collects the TITAN real-time and historical data (using 3G/GPRS, SatCom, Wifi), tagged with time and location. The data can be retrieved and displayed for asset management, incident investigation and driver management purposes, whilst messages, alerts and commands can be exchanged with on-train personnel equipped with WiFi-enabled PDAs.

IRISS has performed a proof of concept demonstration of the TITAN system on both a rural train and a high-speed train in the East Midlands region of England. The added value of Iridium satellite communication as compared to terrestrial networks has been assessed, as well as the continuity and coverage of GPS and EGNOS based navigation capability for railway applications. The development of a pre-operational service together with the involved users is foreseen as a next step.

Reed Solomon SISO Decoding

by Marium Anum

Lancaster University, Communication Department

The aim of this project was to investigate and
implement Soft In Soft Out decoder based on Reed Solomonmore The aim of this project was to investigate and
implement Soft In Soft Out decoder based on Reed Solomon
Codes. This type of error correction is widely used in data
communication applications, such as Digital Video Broadcast
(DVB), optical carriers and Space Data Systems (CCSDS)
primary choice is RS Codes by Consultative committee for deep
space communications signal error correction.

MIT CASTOR Satellite: design, implementation, and testing of the communication system

by Alessandra Babuscia

MIT CASTOR Satellite: design, implementation, and testing of the communication system

by Alessandra Babuscia

Processing Large Data Sets using a Cluster Computing Framework

by Imran Sarwar Bajwa

Australian Journal of Basic and Applied Science 5(6). pp:1614-1618

Increase in the scientific disciplines has caused large data collections as important community resources. The volume... more Increase in the scientific disciplines has caused large data collections as important community resources. The volume of interesting data is already measured in terabytes and will soon total in peta-bytes. This research proposal presents the issue of processing massive amount of satellite data. A single LEO satellite sends around 2 GB of data in 24 hours of a day. To process this huge amount of data, normal digital computers face constraints like processing time, recourses and cost. A solution is needed that can provide quick way of processing at low cost. Cluster computing is network based distributed environment that can be a solution for fast processing support for huge sized jobs. A middle-ware is typically required in cluster computing. In this proposal a middle-ware is proposed for handling the existing processing problems in distributed environments. In a typical heterogeneous computation, a middleware can be employed to provide incorporation and interoperability in the underlying applications and services.

An SNR Dependent Model for the CDMA FLL

by James T. Curran

James T. Curran , Gérard Lachapelle , Colin C. Murphy - Signal Processing, IEEE Transactions on

The tracking bandwidth and variance of the CDMA FLL are considered in this paper. It is shown that the behaviour of... more The tracking bandwidth and variance of the CDMA FLL are considered in this paper. It is shown that the behaviour of the discriminator can vary significantly with varying SNRc with corresponding variations in loop performance. A model is presented which reflects this SNRc sensitivity and, thus, facilitates accurate loop design.

Comparative performance evaluation of TCP Hybla and TCP Cubic for satellite communication under low error conditions

by Shrisha Rao

Co-authored with Siddharth Trivedi, Sanjay Jaiswal, and Rituraj Kumar. 4th IEEE International Conference on Internet Multimedia Systems Architecture and Application (IMSAA-2010), Bangalore, December 2010. doi:10.1109/IMSAA.2010.5729424.

Satellite communication has become important in the current global data communication due to its large coverage area.... more Satellite communication has become important in the current global data communication due to its large coverage area. Satellite links are affected by two major concerns: long propagation delays, and relatively high error rates. Standard TCP congestion control variants were not designed to address these challenges. They generally depend on round trip times (RTTs), and hence suffer heavily if the RTTs are large. Various TCP variants like Hybla have been proposed in order to optimize the channel throughput in heterogeneous networks incorporating satellite links. The error rate of satellite channels can be substantially mitigated using forward error correction (FEC) techniques. In such a situation, according to the results obtained by our comparative study, the performance of Cubic, which is designed for high-speed networks, is better than Hybla, in conditions of high-latency and low error rates.

People Shall Dwell Alone: The Effect of Transfrontier Broadcasting on Freedom of Speech and Information in Israel

by Amit Schejter

ARGOS: HYPER AMPLIFICATION MANIFOLD FOR ENHANCING GROUND STATION RECEPTION

by Ronnie Nader

An integrated Satellite-HAP-Terrestrial system architecture: resources allocation and traffic management issues

by Enrico Natalizio

This paper explains the potential role of an integrated Satellite-HAP-Terrestrial system. A simple and suitable... more This paper explains the potential role of an integrated Satellite-HAP-Terrestrial system. A simple and suitable architecture is presented. The proposed architecture consists of three layers: the Terrestrial Layer, HAP Layer and GEO Layer. The terrestrial layer’s terminals within the same HAP coverage area have to use HAP transponder and HAP Master Control Station (HMCS) to send and receive data amongst themselves. Moreover the HAP Gateway stations (HGTW) guarantees communications among users belonging to different HAP coverage areas using the CEO satellite links. Since high quality multimedia application support is a key objective for upcoming communication systems, this paper investigates the issues related to this topic. In order to guarantee an adequate quality of service to these kinds of service, it is required an efficient resources allocation and traffic management algorithm to be implemented inside the HMCS and HGTW stations.

Wireless communication networks via aerial platforms: Dynamic fair power sharing admission control for UMTS real time traffic sources

by Enrico Natalizio

Cellular communications using High Altitude Platform (HAPs) are studied for next generation broadband wireless network... more Cellular communications using High Altitude Platform (HAPs) are studied for next generation broadband wireless network providing also Third Generation (3G) mobile services. The Connection Admission Control (CAC) issue in a HAP-UMTS communication system represents a key problem in order to increase the capacity in terms of admitted users preserving the agreement quality of service. The main problem of a full centralized admission control approach consists in an excessive calls blocking for the traffic sources located in the middle of the aerial platform coverage area, due to the high additive interference level generated by all active users. With the aim of resolving this issue, we propose a novel strategy for the admission procedure, based on dynamic power sharing (DFPS), in order to guarantee a high fairness level to all users of the implemented cellular system, in term of calls blocked in each cell. Furthermore, we compare this approach with a previous one based on full centralized power sharing (FCPS). Simulation results show that the proposed CAC scheme can achieve better performances than the previous one, managing the active connections in a “fair” manner also under high load
conditions.

Dynamic fair power sharing admission control for HAP-UMTS communication system

by Enrico Natalizio

Cellular communications using High Altitude Platform (HAPs) are studied for next generation broadband wireless network... more Cellular communications using High Altitude Platform (HAPs) are studied for next generation broadband wireless network providing also Third Generation (3G) mobile services. The Connection Admission Control (CAC) issue in a HAP-UMTS communication system represents a key problem in order to increase the capacity in terms of admitted users preserving the agreement quality of service. The main problem of a full centralized admission control approach consists in an excessive calls blocking for the traffic sources located in the middle of the aerial platform coverage area, due to the high additive interference level generated by all active users. With the aim of resolving this issue, we propose a novel strategy for the admission procedure, based on dynamic power sharing (DFPS), in order to guarantee a high fairness level to all users of the implemented cellular system, in terms of calls blocked in each cell. Furthermore, we compare this approach with a previous one based on full centralized power sharing (FCPS). Simulation results show that the proposed CAC scheme can achieve better performances than the previous one, managing the active connections in a “fair” manner also under high load conditions.

Compact Ka-band lens antennas for LEO satellites

by Jorge Costa

Jorge R. Costa, Carlos A. Fernandes, Gaël Godi, Ronan Sauleau, Laurent Le Coq Le Coq, and Hervé Legay, “Compact Ka-band Lens Antennas for LEO Sat-ellites,” IEEE Transactions on Antennas and Propagation, Vol. 56, Nº 6, pp. 1251-1268, May 2008

This paper presents and compares two new compact lens antenna configurations for data link communications with LEO... more This paper presents and compares two new compact lens antenna configurations for data link communications with LEO satellites at 26 GHz. These lenses match a secant type radiation pattern template in the elevation plane while having a mechanically scanned sector beam in azimuth to enhance gain as much as possible. No rotary joints or multiple feeds are required and emphasis is put also on the compactness of the proposed solutions (< 6 lambda). Two alternative lens configurations are evaluated numerically and experimentally: one is based on modified axial-symmetric dome lens geometry, and the other one consists of a full 3-D double-shell lens antenna. In contrast to current nearly omnidirectionnal antennas, the directivity of our lens prototypes is above 15.4 dBi. Up to 4.2 dB loss obtained in the prototypes can be significantly reduced by using lower loss dielectrics and matching layers, without affecting the conclusions. The numerical and experimental results are in good agreement with the radiation specifications given the compact size of the antennas.

HERMES-A/MINOTAUR: The first Internet-to-Orbit Gateway

by Ronnie Nader

Front-end filtering and quantisation effects on GNSS signal processing

by James T. Curran

James T. Curran, Daniele Borio, Colin C. Murphy.

Traditionally, the effects of presampling filtering and of quantisation on the processing of GNSS signals have been... more Traditionally, the effects of presampling filtering and of quantisation on the processing of GNSS signals have been dealt with in isolation. Analysis of the losses incurred during the quantisation process has almost invariably been based on the assumption that the signals at IF are distorted by additive white Gaussian noise. This paper, in contrast, considers the joint effect of filtering and quantisation, illustrates the need to consider these losses jointly and presents novel expressions for the total loss incurred.

Reducing Front-End Bandwidth May Improve Digital GNSS Receiver Performance

by James T. Curran

James T. Curran, Daniele Borio, Gérard Lachapelle and Colin C. Murphy.

Anovel evaluation of filtering and quantization losses for weak DS-CDMA receivers is presented. Using this method,... more Anovel evaluation of filtering and quantization losses for weak DS-CDMA receivers is presented. Using this method, joint optimization of filter center frequency and bandwidth is conducted for one-, two- and three-bit quantizers. It is demonstrated that a joint loss-analysis of these effects is necessary to optimize front-end design.

Digital GNSS PLL Design Conditioned on Thermal and Oscillator Phase Noise

by James T. Curran

James T. Curran , Gérard Lachapelle , Colin C. Murphy - IEEE Transactions on Aerospace and Electronic Systems

Both thermal and oscillator phase noise pose significant difficulties for PLLs in consumer grade GNSS receivers... more Both thermal and oscillator phase noise pose significant difficulties for PLLs in consumer grade GNSS receivers employing low quality oscillators. Unfortunately, these phenomena impose conflicting constraints on the PLL design and so a trade-off between noise rejection and tracking error must be made. This paper develops design rules for optimal, Wiener filter based PLLs conditioned on the influence of the oscillator and of thermal noise on consumer-grade receivers. The performance of these PLLs is examined through both simulation and the use of actual GPS signals.