Scads of acronyms and technologies cloud the crystal ball used to predict the future of wireless broadband. But look closer, and two things become abundantly clear.
First, we're headed toward fast, ubiquitous access that will lead to a new mix of business and personal applications. Experts agree that before long, anything you can do at your desktop, you'll be able to do on the road with a laptop or other mobile device.
"The mobile application of the future is the Internet," says Mike Roberts, an analyst at research firm Informa Telecoms & Media in London. "Once you get to the kinds of speeds we'll be seeing, the application is whatever is successful over the Internet."
And second, that future starts now, say most experts. Later this year, we'll start seeing mobile speeds several times faster than third-generation (3G) cellular data speeds in the U.S. and Korea and, very possibly, other locales. From there, speeds will ramp up quickly — as will the number of places where these speeds are available. It shouldn't be more than a few years before you'll have access to ultrafast wireless broadband speeds, whether you're in Beijing or Boston.
Future generations of mobile broadband are likely to be based on a technology called OFDMA (orthogonal frequency division multiplexing access). This is a more efficient radio modulation method than OFDM (orthogonal frequency division multiplexing), which is already being deployed in increasingly common fixed WiMax networks.
At present, the most visible type of OFDMA network is mobile WiMax. A small network using this advanced technology is being rolled out in Korea (it's actually a close variant of mobile WiMax called WiBro). However, the biggest mobile WiMax build-out on the horizon is Sprint Nextel Corp.'s network in the U.S., which will initially be available late this year, the company says. Sprint says its network will offer typical download speeds ranging from 2Mbit/sec. to 4Mbit/sec. and will cost users less than its cellular Evolution-Data Optimized (EV-DO) network.
If you live in or visit Seoul, Chicago or Washington, the future of mobile wireless has already started — and you'll be able to use WiMax this year. Sprint promises that its network will be available to 100 million users in the U.S. by the end of 2008.
Beyond mobile WiMax, however, the migration from 3G to more sophisticated networks becomes complex. The migration path varies widely depending on the carrier, the country and a host of other considerations, such as the availability of radio spectrum. But experts agree that all paths lead to OFDMA. Here's how we'll get there.
CDMA
The current state of the art for Code Division Multiple Access carriers is EV-DO Revision A, which provides roughly the same download speeds but faster upload speeds than the first generation of EV-DO. Most carriers that have already deployed EV-DO are now upgrading their systems to "Rev A." CDMA carriers are found throughout the world but are most common in the U.S., Latin America and parts of Asia.
The next upgrade may be EV-DO Revision B. This would increase speeds to theoretical maximums of about 73Mbit/sec. for downloads and 27Mbit/sec. for uploads. Roberts says this technology is actually ready but that carriers may skip this upgrade.
"If you talk with Qualcomm, which created Rev B, it's ready to go," Roberts says. "But I haven't heard of any operators deploying it." That's because carriers are busy upgrading to Rev A, and Rev B is considered merely a way station before the next big upgrade, called Ultramobile Broadband (UMB), which once was called Revision C. As a result, many believe that carriers will bypass Rev B and jump right to UMB, Roberts says, which will enable theoretical maximum download speeds of 280Mbit/sec.
Note that theoretical speeds are rarely reached. Real-world speeds depend on many factors, including how many people are using the network and how far each user is from a base station. Real-world speeds are typically a fraction — say, one-fourth or less — of theoretical speeds.
UMB "is still subject to debate," says Roberts. "UMB is pretty ambitious — it's the move to OFDMA, and it uses MIMO [multiple input, multiple output intelligent antenna technology]. Deployment could be in the 2009 to 2015 time frame. It's a matter of timing, and it looks, on paper anyway, that Rev B could be squeezed out."
The stakes of migrating to UMB are high for carriers, Roberts says. For one thing, it is OFDMA technology, so it won't be backward-compatible with the various versions of EV-DO. And because it is new technology, it will require a much larger expenditure by the cellular service providers. Finally, it will require a lot of spectrum.
"This is a whole new ball game — it's a break point," Roberts says.
GSM
Worldwide, there are many more Global System for Mobile Communications carriers than CDMA carriers. For instance, virtually all carriers in Western Europe use GSM technology. And these carriers and others worldwide are undergoing a similar transition to faster wireless using somewhat different technology. For these carriers, 3G started out with a technology called Universal Mobile Telecommunications System (UMTS), but most carriers have been upgrading to High-Speed Downlink Packet Access (HSDPA). Following that will be a transition to High-Speed Uplink Packet Access (HSUPA).
Just as UMB is the next major technology shift for CDMA carriers, the next leap for GSM carriers after HSUPA is Long-Term Evolution (LTE). The goal for this technology is 100Mbit/sec. download speeds and 50Mbit/sec. upload speeds.
LTE is nearer than you might think, but it faces some serious hurdles. Not the least of them is that LTE has not been standardized yet, although Roberts says that should occur in 2008, so deployment could start as early as 2009. He added, however, that that date might be too optimistic.
Also, like UMB, LTE is a major upgrade for cellular operators — "a forklift update," not an incremental one. However, one goal of LTE is to be backward-compatible with 3G networks, and it is expected to be an IP network.
>>> Mobile WiMax
The evolutionary paths of GSM and CDMA carriers are relatively simple to chart. But things get complex when you add mobile WiMax into the mix.
Mobile WiMax is something of a wild card because it's a new technology, not an evolution of an existing one as is the case with 3G. It also will be the first large-scale IP-based mobile network.
It's also a wild card because there must be enough wireless spectrum available before mobile WiMax can be deployed. And that depends on a variety of factors, such as how much spectrum remains available in any given country, how the spectrum is doled out by each government and how much spectrum the individual carriers already control. And these questions remain undecided in many parts of the world, including the European Union.
It's even a wild card in the U.S., where spectrum debates are more settled and only one carrier, Sprint, has enough spectrum to create a truly nationwide mobile WiMax network.
The result, if WiMax technology's advocates are to be believed, will be faster service than 3G for less money. Plus, given the evolutionary path that the other cellular service providers in the U.S. must follow, it could be years before they can catch up to Sprint Nextel.
"If Sprint does it well, they'll have more than a two-year head start," says Derek Kerton, principal of The Kerton Group, a telecommunications consulting firm in San Jose. "Being cheaper [than 3G] is huge. Cheap is something IT guys have to go through to get that ERP or SFA [sales force automation] application out there. The second thing that's huge is that [IT personnel] will be able to go out and buy a laptop with WiMax embedded."
That's because Intel, a major backer of mobile WiMax, has promised to embed the technology in its laptop chip sets, just like it has embedded Wi-Fi into chip sets.
Kerton cautions, however, that mobile WiMax faces many hurdles, not the least of which is that it's an unproven technology. Specifically, questions remain about how the network will perform when it is fully loaded with users.
Skeptics, including Kerton, say they have a host of other technical concerns about WiMax. Sprint and Intel have repeatedly said those technical challenges will not be serious problems.
UMTS TDD
There are a few additional wireless broadband technologies that could find a place in the mobile world. Perhaps the most notable one is UMTS TDD (Time Division Duplexing). Developed by a small company called IPWireless Inc. in San Bruno, Calif., it is actually an older wireless broadband technology.
"Three or four years ago, there were real [UMTS TDD] customers with cards in their laptops using it," Kerton says. "But it was a case of the tree that fell in the forest."
UTMS TDD offers roughly the same performance as mobile WiMax, and it's a proven technology, so why hasn't it been widely adopted? The big blow to this technology came with Sprint's decision to go with mobile WiMax after considering UMTS TDD for its U.S. network.
But that doesn't mean UMTS TDD is a goner. It's still scheduled to be deployed on a nationwide network in Japan.
In addition, the technology may have found a niche in Europe for mobile TV. Orange SA, a large international cellular carrier, is deploying UMTS TDD for that purpose.
The Future
Whichever technologies eventually win out, several things appear certain. First, it won't be long before mobile network data speeds increase dramatically. That, in turn, will change the applications we use when we're mobile.
It is also certain that new technologies such as LTE, UMB and mobile WiMax aren't fourth-generation, which is expected to have 1Gbit/sec. speeds. However, the future of 4G remains murky.
"It's tough for us forecasting types to talk about 4G, because it's so far out [that] it's hard to predict," Roberts says. "LTE, UMB and the next flavor of WiMax are getting close to 4G, though, but it could be 2015 or 2020 before we see real 4G."
Haskin is a Computerworld.com contributing editor. He specializes in mobile and wireless technologies. Contact him at dhaskin@earthlink.net.
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