Before the Internet

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From the course by Institut Mines-Télécom

Introduction to Satellite Communications

179 оценки

Institut Mines-Télécom

Introduction to Satellite Communications

179 оценки

How is a satellite built? How do they fly? How do they communicate and how does the network operate? You will get all the answers in this course from teachers and researchers from three schools associated with Institut Mines-Télécom. The course is made of : teaching videos, equipment demonstrations and simulation programs. They will guide you through the discovery of satellite communications. Professionals in the space field will share there vocation for this scientific and technical sector. Have you ever wanted to know more about transponders, the geostationary orbit, QPSK modulation, channel coding, link budget, TCP over large bandwdith x delay product links ? This course is for you! This course is available in English: French-speaking lecturers with English subtitles and fully translated contents (slides, practices). This MOOC is supported by the Patrick and Lina Drahi Foundation.

From the lesson

Networking and services

This module explains how services such as voice, television and Internet access are provided by means of communications satellites.

Introduction2:55

Before the Internet4:12

Internet and the notion of network3:51

Interconnection and interoperability: a real issue5:16

The notion of protocol6:17

Going further: Internet Protocol and the hourglass4:18

Meet the Instructors

Laurent Franck
Professor
IMT Atlantique, on leave to Airbus Defence & Space as of September 1st, 2017
Tarik Benaddi
Assistant Professor
IMT Atlantique
Julien Fasson
Associate Professor
INPT/ENSEEIHT
Nathalie Thomas
Associate professor
INPT/ENSEEIHT
Marie-Laure Boucheret
Professor
INPT/ENSEEIHT

-Now that we have reviewed the major strengths of satellite systems,

let us have a quick glance at the services of a satellite system.

Nowadays, you are immersed in the Internet.

Almost all your communication means are more or less linked

to the Internet or go through the Internet. But before the Internet,

there were telecommunication services already provided by satellite systems.

I roughly split them in two parts.

First broadcasting services that are the cheapest for a satellite system

because economically speaking, a satellite naturally broadcasts.

Thus, sending a message to one person or to everyone under the cover

exactly costs the same. So if we consider a satellite

with an important coverage and natural broadcasting,

a broadcasting service is fully adapted.

Thus satellites are particularly well-adapted to television services.

We more rarely think of other broadcasting services

such as radio broadcasting or even data broadcasting to feed caches.

The first telecommunication satellite, strictly speaking,

that ever existed was Telstar 1. In 1962, it already provided

a television service between the USA and Europe.

Unfortunately, it used a satellite with a lower orbit

than a geostationary satellite. We noticed that when we did not have

a fixed relay for broadcasting, it was rather complicated.

Thanks to the evolution of launchers, we managed to send a satellite

at a distance of 36 000 kilometers from Earth, a geostationary satellite,

and create a fixed relay to continuously broadcast television

over a large coverage. The higher, the larger the coverage.

This is the first type of services, broadcasting services:

There is a second type

that I called niche services. Niche services are specific services,

hence the word "niche". We offer communication means

in unusual locations or for contexts in which only satellites

can provide this communication. We can think of the interconnection

of isolated remote sites, the headquarters of an oil company

in a major European city, and its offshore stations for example.

To interconnect them, there is nothing better than a satellite system.

Storage management in companies spread out all over the world

can also be done through a satellite system.

You can also consider boats that want to communicate with each other

or with their headquarters. In that case, a satellite system can be used.

One last example. In the event of natural disasters,

earthquakes for example, a satellite system can be deployed rather quickly.

You only need to install your transmitter and power generator.

You will then be able to transmit and receive information and communicate.

These services are specific. Since they are specific,

the satellite will be created to provide these services.

This will add significant costs. This was before the Internet.

Let us now get to the evolution with the Internet.

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