Article: Cell phone technology
Everyone knows what a cell phone is. But few people understand how the network their cell phone connects to works. Yet, knowing this can be very important since the technology behind the network is what determines the features you have access to. For example, if you connect to an analog network, chances are it won't be around for much longer, since the providers all switched to digital networks and they no longer promote any analog phone. Another thing that can be affected by what type of network you are using is the speed at which you can receive emails or browse the web from your mobile devices.
The first thing to know is if the network is analog or digital. Chances are if you have a modern phone and you live in a city you are connected to a digital network. Cell providers keep their analog networks running because the digital ones have not yet reached every rural home, but they are getting there very fast. Also some people, very few nowadays, are still using older phones that could only support analog connections. If you have an analog phone, chances are the best you can do with it is voice calls and SMS messages (short messages).
Digital networks come in many flavors. There's also several ways to categorize them: either by technology or by speed. The most common digital networks are CDMA (Code-Division Multiple Access) which is used by more than half the customers in North-America, and a few other countries such as South Korea, TDMA (Time Division Multiple Access) used by a few providers mainly as an older digital technology, and GSM (Global System for Mobile communication) which is by far the most used digital technology, which covers all of Europe, nearly half of North America, and most other countries. Recent studies show there are more than 1.5 billion GSM cell phones world wide. These technologies are refered to as 2G (Second Generation).
Comparing these 3 technologies can be tricky, but for normal uses like voice calls, SMS, MMS (multimedia messages) and basic web browsing, they all work as well. Each provider usually supports either CDMA (Like Bell Canada and Telus in Canada, Verizon and Sprint PCS in the US) or GSM (Rogers Wireless and Fido in Canada, Cingular, T-Mobile in the US, and all of Europe). So it really comes down to the choice of the phone itself. Some people say GSM phones are cooler and more plentiful, which may be because the biggest market is in GSM, and also Nokia, an european company, has the biggest market share.
Where it may be useful to compare these technologies is when you want to do more advanced things. For example, GSM phones come with what is called a SIM card. This is a very small card in your phone containing information such as your phone number, address book, and the setup information on how to connect to your provider. This means when you upgrade, or if you have more than one phone, you can remove your SIM card from the phone and insert it into the next easily. While it's technically possible to use a SIM card in CDMA phones, very few phones support it and networks do not.
Another thing to know about the network you are using is the frequency. For example, GSM is usually used on the 850, 900, 1800 and 1900 MHz frequencies. In Europe, 900 and 1800 MHz are used, and in North America it's 850 and 1900 MHz. The main thing to remember about this is that the lower the frequency, the better your connection will be. However, the higher the frequency, the farther the cell tower can transmit. So if you have a phone that supports 850MHz and are near a tower which also supports it, you will have a better voice quality, higher download speed, and less call drops. However, it also means your provider will have to install more towers to cover the same territory, so in rural areas chances are only 1900 MHz will be provided. Two terms found frequently with GSM phones are "double band", "tri-band" and "quad-band" or "world" phone. A double band North America phone will support 850 and 1900MHz, which means you can only use it in North America. An european can have the exact same phone but with the 900 and 1800 MHz channels. However if you have a world phone, you can use it anywhere.
CDMA phones also use similar frequencies, but the main difference is that GSM phones are only digital, but CDMA and TDMA phones usually support both digital and analog. For example, a CDMA phone may support analog on 850 MHz, digital on 850 MHz and digital on 1900 MHz. Someone who has to travel far from cities on a regular basis should look at provider coverage maps to know if there are places where digital is not available yet, and these phones can be useful for that. So depending on what you want to do, you may want to decide on a CDMA or a GSM provider.
As we look to the future, we'll see the world migrating to two new technologies. Most CDMA companies are going to EVDO (Evolution Data Optimized) which is a CDMA2000 technology, while many GSM providers are moving to UMTS (Universal Mobile Communication System) also sometimes called W-CDMA, which interestingly enough has no relation with the CDMA technology. The main goal is to provide more speed for things like mobile web browsing and streaming of media content. These are refered to as 3G (3rd Generation) technologies and with these, providers will be able to deliver up to 15 Mbps speeds, which is more than most people currently have with broadband Internet connections. These new networks have already been deployed and are in early testing phases in Europe, and are currently being deployed in North America and other countries. By the end of 2006, most of the new smartphones and high end cell phones sold will be using these technologies.