Use of Satellites in Wireless Communication

Satellite refers to any object, be it artificial, manmade, or natural, that orbits around a celestial body such as a planet, moon, or asteroid. Devices we are mostly interested in are manmade ones. What are satellites used for? Plenty of things. They orbit the Earth, and help in communication, relay TV and phone signals, predict different natural calamities, and so on.

This article will look at what satellites are, how they operate and explains different satellite uses, along with interesting facts about satellites.

How Does a Satellite Work?

Communication satellites are nothing but a buffer for transmitters and receivers scattered across many locations on Earth. TheyBut as communication satellites can receive signals from one point on Earth and transmit it to another point that is thousands of miles away, they made global broadcasting and long-distance communication far easier. are used for distributing television signals, radio frequencies, and the internet.

Many traditional communication satellites orbit the Earth at around 35,786 km above the surface, a location known as the Clarke Orbit or geostationary orbit. However, modern communication satellites can also operate in much lower orbits. Currently, more than 10,000 active satellites are orbiting the Earth, along with tens of thousands of other tracked objects such as inactive satellites and fragments of debris. Many of these satellites are used for communication, but others serve purposes such as Earth observation, navigation, scientific research, and military monitoring.

Advantages of Satellites

Some would argue satellite communication only has advantages. But they do have some serious disadvantages too. Let’s find out.

The first and most obvious advantage of satellite communication is that it can cover a wide area without any significant transmission strength loss. Before communication satellites, people used to rely on linear radio transmission. But radio frequencies could not penetrate large buildings and mountains in its path. Thus, radiofrequency was only applicable for covering a smaller area.

But as communication satellites can receive signals from one point on Earth and transmit it to another point that is thousands of miles away, they made global broadcasting and long-distance communication far easier.

Today, satellite communication supports global television broadcasting, international communications, and connectivity in remote regions. However, many TV, radio, and internet signals are also transmitted through fiber-optic cables and terrestrial networks.

Currently, communication satellites are used for business networks, private networks, global mobile communication, long-distance mobile communication, military surveillance, space exploration, navigation, and other network transmission efforts.

Use of Satellites in Wireless Communication

Now let’s look at how wireless communication works with satellites. Along with TV and radio signals, communication satellites are also great for mobile and wireless communication. Today’s devices use C-band, Ka-band, and Ku-band.

Ground stations on Earth send a frequency to the orbiting satellites. This is called an uplink. The satellite then transforms this frequency into another signal called a downlink, and relays it to the second ground station.

Different Types of Satellites Used in Communication

There are different kinds of satellites for wireless communication. Their name depends on their orbit. There are four popular Earth orbits—geosynchronous Earth orbit, geostationary Earth orbit, medium Earth orbit, and low Earth orbit.

Satellites that follow geosynchronous orbit circle the Earth from 35,786 km above its surface. Despite having a circular orbit, they can be slightly tilted on the poles. But if anyone took a telescope and observed these devices’ behavior, they will see them at a stationary position.

Satellites placed on a geostationary orbit around the Earth are primarily used for TV, radio, global wireless communication, and weather forecasting.

Satellites that follow medium Earth orbit (MEO), orbit the Earth from a much closer location. These satellites typically operate at altitudes between about 2,000 km and 35,786 km above the Earth’s surface. These devices are used to transmit signals at a shorter distance. When compared to a GEO satellite, signals from MEO satellites usually take roughly 120–150 milliseconds to complete a round trip.

And lastly, we have satellites that orbit the Earth at the lowest orbit. These low Earth orbit (LEO) satellites typically orbit between about 160 km and 2,000 km above the Earth’s surface. Next question — is there a time delay latency between transatlantic communication using wireless or satellites? Thanks to their short distance from Earth, many modern LEO satellites can achieve transmission delays as low as 20–40 milliseconds.

In recent years, thousands of small satellites have been launched into low Earth orbit to create global internet constellations. Systems such as Starlink and Amazon Leo aim to provide broadband internet access to remote regions around the world.

Disadvantages of Wireless Satellites

The biggest drawback of excessive satellite use for communication purposes is, that repairing them can be extremely difficult and expensive. Also, it is very hard for people to bring them back safely to Earth. Sometimes the cost of bringing them back is higher than just abandoning them completely, and this is the most popular method.

Some older satellites were simply abandoned in orbit once their missions ended. However, modern satellites are often designed to either deorbit safely and burn up in the atmosphere or move to a so-called “graveyard orbit.” This has resulted in high amounts of manmade space junk. These abandoned devices are just drifting in free space. They can crash into nearby spacecraft or even on Earth.

Over the years, many treaties have been signed to tackle this space junk problem. Currently, space agencies track more than 36,000 pieces of orbital debris larger than 10 centimeters, along with millions of smaller fragments. Moreover, according to a report published back in 2019, there are currently over 128 million debris (smaller than 1 cm) drifting in space. This free-floating debris has collided with many operational devices, thus causing serious damage to the wireless network.

Moreover, there is a common problem that arises when every nation is trying to send its satellite into the Earth’s orbit. There are a limited number of slots for communication devices. So, who decides who gets which position? These decisions are taken by the International Telecommunications Union (ITU) and the Federal Communications Commission (FCC) to avoid any disputes.

How can we benefit from the low-cost wireless satellites while keeping the space junk at a moderate level? Only time will tell.