While the clarity on your cell phone may be increasing, the overall picture of wireless technology is becoming progressively murkier. New terms and services seem to spin off of the presses every day, and it’s hard to separate what you need to know from what you don’t.
What do all those acronyms mean? Most are specific ways of transmitting what amounts to the same kind of signals. Different phones depend on different technologies, and many of these are manufacturer-dependent.
Let’s clear the air and take a quick look at some acronyms you’re likely to encounter, and what they mean:
If you have an analog cell phone, chances are good you’re using AMPS. That stands for Advanced Mobile Phone Service, the analog phone service used in North and South America. It describes a service that uses the FDMA technology to allow cell phone communications.
While your analog phone may use an AMPS service, your phone is communicating using FDMA. This stands for Frequency Division Multiple Access. It’s an analog transmission technology for cell phone communications. AMPS is the network, while FDMA is the way signals are transmitted.
If your phone is digital, it just might communicate using TDMA. TDMA stands for Time Division Multiple Access. This transmission technology creates a high-speed channel by combining multiple channels into one. It’s digital and it offers three times the apacity of FDMA.
Do you have a QUALCOMM phone? If so, it’s likely that it’s using CDMA to send out its information. CDMA stands for Code Division Multiple Access. CDMA is another digital transmission technology, used by QUALCOMM phones. CDMA is known for its high-quality calls and the long battery life of phones supporting it. It’s an inexpensive technology to put into place and it offers ten times the capacity of analog phone systems. CDMA is used by the military for secure communications – it’s difficult to tap into or jam calls made using CDMA.
An early cellular network in Europe that has since spread to other continents is GSM. GSM stands for Global System Mobile Communications (well, almost – the “C” didn’t make it into the acronym). GSM is a digital service, and it employs the TDMA transmission technology. GSM was originally deployed in Europe but now it’s used in the US, too, on a different frequency. In 2000, about half of the world’s phone users (250 million) were using GSM.
GSM is probably best known for its support of text messaging, letting you type in short phrases and emoticons (up to 160 characters) to send to your friends (who must also have GSM phones). GSM phones also support SIMs. SIM stands for Subscriber Identity Module. SIMs are smart cards that make it possible to borrow phones and program them instantly by hooking them up to your SIM. The cards themselves can be programmed to offer custom menus that follow you around, regardless of what phone you use.
Phones that support messaging are using SMS. That’s the acronym for Short Messaging Service – a text-messaging service supported by GSM networks, allowing users to send messages of 140 to 160 characters. SMS messages are stored at a centrally located site and then forwarded to recipients.
If you’re able to download files using your phone, then you might be using a GPRS service. GPRS stands for General Packet Radio Service. GPRS is essentially GSM with Web support. It supports the TCP/IP protocol and allows both Web browsing and file transfer from cell phones.
An improved and relatively new version of GSM is EDGE. That means Enhanced Data rates for Global Evolution, which is a higher capacity version of GSM and TDMA.
You’ve probably never used a device operating on UMTS (Universal Mobile Telecommunications System), because it’s a technology still on the horizon. It’s a European standard and represents the next step in the evolution of GSM. One day, users will be able to access UMTS networks operating at 2 Mbps. In themeantime, EDGE and GPRS are intermediate steps on the way to UMTS.
When you drive from Seattle to San Francisco and talk on your phone along the way, that’s IS-41 at work. That acronym means Interim Standard 41, a cellular protocol that passes cellular user information from one carrier to another as a user travels between locations in North America. IS-41 is the protocol that allows you to keep chatting on your phone while traveling.
Get your email on your Palm? That’s CDPD, or Cellular Digital Packet Data. It’s a store and forward method (not a direct connection, in other words) of wireless access. It’s based on AMPS, the analog wireless cellular network, but adds IP support. Most urban areas have CDPD support, and several large telephone companies (AT&T, GTE, Ameritech, etc.) have deployed it. CDPD is used to support wireless communications on laptops, PDAs, and other mobile devices.
WAP is the Wireless Application Protocol, which is a protocol that lets you surf the Web and check your email on a variety of devices (so long as everything is text-based). Pagers, cell phones, and other mobile devices use WAP to communicate. When someone pages you, that’s WAP in action.
The menu that you use on your WAP devices is written in WML, or Wireless Markup Language. This is language of WAP devices. When you view menus on pagers or other WAP devices, they’re written in WML, which is a type of XML document developed using XML and HTML tools.
A name that’s in the news a lot where wireless technology is mentioned is NTT DoCoMo. “DoCoMo” is Japanese for “anywhere,” and it’s the cellular company that provides Japan with wireless services – from satellite communications to cell phones and paging.
And if you’ve heard of NTT DoCoMo, you’ve probably heard of i-Mode. i-Mode is an information service provided by NTT DoCoMo for Japan. i-Mode offers its 20 million plus subscribers an almost limitless variety of options for their cell phones. Calendaring, chat, news, games – just about anything available from other cell phone services and the Web is available for i-Mode devices. While its initial throughput was at 9600 bps, speeds have improved and the network now runs at 384 Kbps.
For American users, now there’s m-Mode. AT&T Wireless is offering m-Mode service as an American parallel to Japan’s i-Mode. Much like i-Mode, m-Mode offers real-time access to content you’d expect to find on the Web, all on your cell phone. At the moment, m-Mode is only available in limited areas as it is a relatively new technology.
Because the Japanese began their Internet experience through cell phones, it’s uncertain how m-Mode will fare in the US. Americans expect more from the Internet since most Americans began using the Internet on computers with large screens and keyboards. It’s hard to say if the wireless freedom will outweigh the inconvenience of using such a small device.
There are many, many more acronyms associated with cellular technology. Further muddying the cellular waters are other technologies used by wireless computer networks, some of which overlap with cell phones, and others that are device-specific. Know the ones listed here and you’ll be on your way to understanding the important advances in wireless technology.
http://www.attws.com/mmode/
http://www.techweb.com/
http://www.webopedia.com/
Jackie Rosenberger is an editor with murdok
