Cellular technology: A brief history

Remember those telltale twisty antennas on the roofs of cars in the 1980s? Those cool customers on their car phones were using Advanced Mobile Phone Service, or AMPS. This first-generation analog network may have been cutting edge at the time, but it soon became notorious for its iffy call quality. Even worse, anyone with a police radio scanner can easily eavesdrop on AMPS calls, which travel through the air without any scrambling or encryption. As of February 18, 2008, analog cell phone coverage has been terminated and is no longer in use.

The 1990s marked the arrival of two digital networks: CDMA, popular in the United States and a few other countries; and GSM, the dominant technology overseas. These second-generation (2G) networks spread voice calls across several wireless spectrums, making for more reliable connections that are much harder--though not impossible--for hackers to intercept. More importantly, CDMA and GSM networks are also capable of sending a sliver of data along with voice signals, making possible for such features as text messaging (SMS), caller ID, and conference calling.

Though the move to 2G was a great leap in terms of the technology, the splintering of the CDMA and GSM camps created a mess. At the time, AT&T Wireless, Cingular, and VoiceStream (now T-Mobile) opted for GSM. This required the carriers to adopt the now largely defunct TDMA technology before moving on to GSM. On the other hand, Sprint, Verizon, and a number of smaller carriers chose CDMA. While each side says it has the advantage, the schism resulted in two competing networks with little incentive to create a unifying 3G standard. Conversely in Europe, 3G arrived much more quickly because all carriers were working off a government-mandated standard.

Of course, there were other factors working against 3G's adoption in the United States. Rolling out the new networks was very expensive, and customers had to be sold on the services. Furthermore, the move also involved technological constraints. Carriers had to bridge the gap between slow-as-molasses 2G service and zippy 3G with "2.5G" network enhancements. In operation a couple years now, 2.5G networks let you download ring tones, listen to short audio clips, send multimedia messages (MMS), or surf the Web, albeit slowly. These services include GPRS, which is capable of transmitting and receiving data at an average of about 30Kbps to 40Kbps, or a little slower than standard 56K dial-up service and EDGE, another GSM enhancement that manages about 90Kbps on an average day, or almost twice as fast as dial-up. On the CDMA side is 1xRTT, an early version of CDMA2000, which squeaks in about 60Kbps to 80Kbps. The next step, of course, is 3G and beyond. But some important differences remain.

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