How cellular networks work
Every day, we use technology on a daily basis that we have absolutely no idea how it works. Televisions, radios, computers, microwaves, and automobiles are just a few examples. In many cases, it doesn’t really matter if we know how it works—with one major exception. The cellular phone has become the most high-tech piece of equipment that most people carry with them at all times, and have come to depend on heavily. Unfortunately, we often run into frustrating limits—lack of coverage, poor connections, dropped calls, and roaming charges, just to name a few. Understanding how cell phone networks work can help you better deal with these limits. First of all, why are they called "cellular phones"?
To connect and place a call, cellular phones send a radio wave through the air. These radio transmissions are picked up by a large radio tower. However, there is a limit to how far each radio tower can transmit its signal. The radio tower and its transmission area is called a 'cell', and it only covers a circular (or, technically, spherical) area of just a few miles. How, then, can these towers connect to someone hundreds of miles away?
The answer is that the radio tower transmits your signal to the radio tower next door, which then passes it on to the next radio tower, and so on. Your call travels through several radio tower cells in order to place a call—hence the term "cellular phone".
When your cell phone tells you "no service", this means that you have moved outside of the range of ANY radio tower. Telecommunications companies are building more and more cellular towers across the country ever day, trying to increase their coverage to include all population centers, even small towns, and all major roads (in particular the Interstate Highway system). Consequently, finding yourself in an area so remote that you can't receive a cellular tower signal is becoming increasingly rare. I live, for example, in a small town in New Mexico, and even out here I have be pretty deep into the desert before I can't a cell tower signal.
More often when you get no service, it means you are in a structure built out of materials that block the radio signals. Basements of concrete buildings are particularly notorious for this. In a similar way, radio signals that can get through but are very weak results in a poor connection, because not all of the voice data being transmitted is being received by your phone. In a situation where you have a weak signal, you may lose the signal, resulting in a dropped call.
All cell phones these days have an indicator on the main display showing you how strong of a signal you are receiving. It almost always takes the form of a symbol that looks like a telephone pole, followed by four or five bars. If you have only one bar, you are receiving a very weak signal, and you can expect poor call quality or even a dropped call. To deal with a weak signal or no signal, move above ground, or toward a window. Use the signal indicator on your phone to find a place where you are getting at least two bars. From that location, you have a pretty good chance of placing a complete call of decent quality.
Finally, there is roaming. What is roaming, and why does it cost so much? The trick to understanding roaming is that, although you see cellular towers everywhere, they are not necessarily all owned by the same company. Each major telecommunications company maintains their own cellular network. It is possible that although your phone is receiving a signal, it may be from a cell tower owned by a rival network that you do not subscribe to (this happens a lot out here in New Mexico). You can still place the call, but if you do, your cell phone provider has to pay that rival company a fee for using their equipment. They pass that cost onto you, and that is why roaming minutes are not included in your cell phone plan and cost so much more.
The good news is that more and more cell phone providers are striking deals where they can use each other's cell towers networks on an equal basis. This essentially increases the size of their own networks and makes their customers happier. Consequently, finding yourself in a location where roaming rates apply is becoming more and more rare these days.
We hope this extremely brief introduction to how cellular networks operate has helped you. At least now when something goes wrong with your cell phone, you'll know what's causing it, and how to fix it.