How a typical Satellite Internet works.

Satellite Internet system provides internet access through communication satellites. A geostationary satellite is used in the consumer-grade satellite internet service. In today’s world, the average downlink is 1 Mbit/s and uplink is 256 Kbit/s, in case of internet Satellite Internet.

Process

When a user wants to get into a website, FTP etc. A request is sent to the communication satellite through the ground-based dish, ground terminal or more technically VSAT (Very Small Aperture Terminal). Commonly a two-way gateway and antenna are used.

As commonly the geosynchronous satellites are used as the communication satellite, they usually stay at the same place at about 35786 KMs above us. As they receive the request sent by the ground terminals they send those to the NOC (Network Operation Centre).

NOC receives these requests from the satellite which was sent by the user.

Usually, coverage of satellites are divided into sectors and these sectors have one or multiple NOC to process the data and requests of the user and fetch them the resources they want. Then NOC finds the way to the required servers and pulls the required data.

The NOC receives those as packets NOC transforms it into Radio waves and Send it back to the satellite and the satellite send it back to the user who requested.

As the ground gateways or terminal receives the signal the gateway change it into usable data and provide it to user’s device.

Here the process ends.

Real Case scenario

It seems very simplified. But when we take the real situations into consideration lets us see what happens.

If we consider geostationary satellite the area covered by the satellite is about 1/3 of earth’s surface which is about 170.03 million Km2. So there would be thousands of users connected to one single satellite at once. So in other terms, one satellite handles thousands of request from thousands of user gateways. To keep track of all those gateways and requests, the gateways are given unique ids so that proper information is delivered to the proper gateway.

One NOC cannot provide all the information to such a large number of users. So usually groups of NOC are used to provide all the information needed by users. NOC’s sometimes uses caching servers and high-speed DNS to provide speed to the users.

But if we compare the typical satellite-based internet with the physical connection we can find a difference in latency and speed. But when we consider both of them in rural or remote locations we start seeing the difference. Physical lines usually lack connectivity in rural or remote locations, also as the distance between the network provider and user increase the problems in connection and latency increases in the ground-based system.

NOC usually use a ground based connection to fetch the required data from server which users demands.

To be true a typical satellite internet access is not fully satellite based, it still uses the underground and submergible undersea cables to fetch your data.

The satellite-based internet access system usually bottlenecks itself due to the distance of the satellites. They are so far from their users that they face a signal latency. Typically it takes radio signal 120 ms to reach the geostationary orbit. And again the same when satellite communicates it to NOC. It happens when the conditions are perfect.

It has some uses in the field that can’t be replaced by any other technology.

These might change after the commercial availability of Starlink. It will reduce the load on the sub marine communication cable. Let’s see where Starlink take us. Stay tuned for new and interesting topics.

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