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How Cell Phones Work
Written by: Levetta Rivera
Each day thousands of people in the United States purchase cellular phones. At that rate it is likely that someone you know owns a cell phone and uses it on a regular basis. They are such great gadgets - and there are a ton of cool cell phone accessories you can buy to make yours stand out from the crowd. With a cell phone you can talk to almost anyone from just about anywhere, because approximately 80% of the U.S. has coverage. Cell phones have come a long way in a relatively short period of time but have you ever wondered exactly how a cell phone works?
A cell phone is nothing more than a sophisticated radio. A good way to understand the sophistication of a cell phone is to compare it to a CB radio. A CB radio is a simplex device. A simplex device is one in which two people communicate on the same frequency, so only one person can talk at a time. A cell phone is a duplex device, so it uses one frequency for talking, and a second separate frequency for listening. A CB radio has 40 channels. A cell phone can communicate on 1,664 channels. Cell phones also operate within cells and they can switch cells as they move around. Cells give cell phones incredible range. A CB radio can transmit about 5 miles. Someone using a cell phone, on the other hand, can drive clear across a city and maintain a conversation the entire time. Cells are what give a cell phone its incredible range. Cellular phone system technology is amazing in that a city can be chopped up into small cells that can allow extensive frequency re-use across a city. Frequency re-use is what lets millions of people own cell phones without problems. It works because the carrier chops up an area to about 10 square miles.
Cell phones have low-power transmitters in them. The base station also transmits at low power. The advantage of low power transmission is that the power consumption of the cell phone, which is normally battery-operated, is relatively low. Low power means small batteries, and this is what has made hand-held cellular phones possible. Another advantage is that the transmissions of a base station and the phones within its cell do not make it very far outside the cell. The same frequencies can be reused extensively across a city. Cellular phone systems require a large number of base stations in each city regardless of the size. The average large city can have hundreds of towers. In addition to towers, each carrier in each city also runs one central office called the Mobile Telephone Switching Office (MTSO). This office handles all of the cellular phone connections to the land-based phone system and controls all of the base stations in the region.
Cell phone technology is amazing and improving everyday. It is hard to imagine life without this little gadget.
©copyright2004 Levetta Rivera, How Cell Phones Work. All rights reserved.
About the Author
Levetta Rivera is a successful author and publisher of http://www.freecellphones-bestdeals.com. An informational resource site to cellular phone deals, cell phone accessories and service plans.
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