HOW CELL PHONES WORK
PART I
THE LONGEST LIST OF THE LONGEST STUFF AT THE LONGEST DOMAIN NAME AT LONG LAST

How does a cell phone work?

It’s hard to walk or drive anywhere today without seeing someone talking on their cell phone. Because these techno gadgets have become so popular, one may think that they work quite easily, all it takes is a phone and a cell phone tower. In truth, the actual process of a cell phone working is much more involved and complicated than we would think. The entire workings of a cell phone are only going to become more complex as people can do more and more on their cell phones with every new model that comes out, which is just about every week it seems. Whether you use your cell phone to talk, to watch TV, to organize your schedule, to play games, or to access the Internet, they are all based on the idea that they are actually a radio. It’s a very complex radio that has been combined with a telephone and as soon as you understand that, you can begin to understand how the cell phone works.

You could say that the very first cell phones were back when people installed radio telephones into their cars, if they needed a mobile form of communication. Because these radio telephones involved only one central antennae tower that held approximately twenty-five channels, if someone wanted a radio telephone in their car, the car would need to have a transmitter that had the capacity to travel as much as fifty miles. Twenty-five channels is also not very many so not everyone, not even the majority of the people, could have the radio telephones installed in their cars. The cellular system took one major cell, that cell being the city, and broke it up into multiple cells that were much smaller. This allows any number of people to use a cell phone at the same time.

To understand how a cell phone works, you need to be familiar with different terms. These are: duplex, channels, and range. Duplex refers to how people actually communicate on a phone. Walkie-talkies and CB radios are half-duplex devices. This only allows one person to speak at one time. Cell phones operate on a full-duplex system, which means that both people can speak to each other at the same time. This is because a full-duplex system involves two different frequencies. The first frequency is used for when the person speaks and the second frequency is used when the person listens. The first and second frequencies are completely separate entities of each other.

A cell phone can have as many as 1,664 channels or more. Imagine how many that is when you compare a CB radio, which has forty channels and a walkie-talkie, which has one channel. The range refers to how far of a distance you can travel while still speaking to one person. A walkie-talkie has a range of approximately one mile and because CB radios are more sophisticated, they generally have a range of approximately five miles. Because cell phones work according to the small cells that have been divided up using the one large cell, the range from the cell phone will simply the follow the person as they travel and talk on the phone. This means that one person can talk on a cell phone while travelling hundreds of miles and carry on the same conversation with the same person.

Every cell phone carrier has approximately eight hundred cells that they can distribute throughout the city. The carrier then splits the city up into the different cells that they would like to use. Each cell is approximately ten square miles large. Within each cell is a base station. These base stations house one tower with a small building nearby. These buildings hold all of the radio equipment. Each cell will use approximately one-seventh of the duplex voice channels that are available to the carrier. Because of this, the cell will have its own set of frequencies and will not interact with any other frequencies. This means that the number of duplex voice channels that one cell has available is approximately fifty-six, which means that that cell will allow fifty-six people to talk on their cell phone at the same time. This is typical for analog cell phones and if the cell phone is a digital cell phone, there will be many more channels available.

PART 2

 

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