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Fourth generation wireless has no official definition; it means different things to different people and seems so far out on the horizon, it's barely worth mentioning. All the more reason to start working on it now, say technologists.
AT&T Wireless sees 4G as "the equivalent of a wireless cable modem," according to Nelson Sollenberger, division manager, wireless system research at AT&T Labs. AT&T is a strong proponent of an asymmetric mobile data network combining orthogonal frequency division multiplexing and third generation EDGE technologies, to provide broadband mobile downlink access at peak rates of up to 10 megabits per second while EDGE offers uplink access at 384 kilobits per second.
The technologies complement existing plans for the 3G evolution of AT&T's time division multiple access mobile network as well as its fixed wireless efforts, according to Phil Redman, an analyst with Gartner Group. But Redman is concerned that AT&T has not yet shown it can deliver the next-gen technology cost effectively. "And the rates aren't better than what MMDS offers today," he says.
Data rates are a big part of all 4G discussions and range anywhere from 5 Mbps on up to 80 Mbps. Twenty Mbps gets mentioned most often but even that could be overkill, according to Rich Howard, wireless research vice president at Lucent Technologies' Bell Labs. "A high-definition TV signal is 15 Mbps. I don't know how someone could handle more data than that," he says. Furthermore, Howard believes there is a "practicality" limit to most technologies, despite the ability to further advance them.
He cites airplane speeds as one example. Even though supersonic planes were introduced in 1976, the vast majority of all airplanes fly no faster than they did in 1963. Even though technology has improved, it isn't "practical" or cost effective to fly planes at higher speeds. The same will happen with wireless technologies, says Howard.
Cost-effective 4G technology-regardless of data rate-is a major objective of all manufacturers. And it is one issue about which network operators need to be especially concerned.
It doesn't matter if an operator can deliver streaming video at 1 Mbps if it's going to cost the subscriber $600 an hour. Even MP3 audio (100 kbps) is prohibitive at a potential cost of $60 per hour. That's with current network infrastructure technology and service rates of course, but it shows how far network designers and infrastructure manufacturers have yet to go.
Yet, the talk of high-bandwidth wireless services is little more than just talk to some analysts. Jane Zweig, executive vice president of Herschel Shosteck Associates, Ltd. says she doesn't doubt that some day mobile wireless users will have usable streaming audio and video to their devices, but she questions the value of focusing attention on 4G when 3G has not yet been commercially deployed in any meaningful sense and even 2.5G platforms remain commercially unproven.
Zweig cites the general packet radio services platform as a prime example. While faster rates have been demonstrated, operators aren't getting "much better than 9.6 kbps and the devices still aren't there," she says. Recent hype surrounding 3G and 4G technologies makes her wonder about the real-world problems in delivering what's been promised so far.
Nevertheless, the consensus among those working on 4G seems to be that eventual implementation-regardless of how 3G fares-can only be helped by early discussion of expectations, technologies and capabilities.
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