The WiMAX Evolution: Bring in the Standards Suspects

The 802.16 standard promises to extend the range of wireless networks to support entire communities.

By Esther Schindler

Wireless networks have changed the way we work. You might be reading this article on your laptop in Starbucks, from a public access computer in your local library, sitting on your back patio at your home office, or in your company's conference room (while the presenter drones on and on -- please remember to keep a polite expression on your face). Whether in an airport or on an enterprise network, today's users expect mobility.

But WiFi has limitations. The 802.11a/b/g standards that define WiFi's most commonplace wireless networking protocols have a limited range, with practical usable distances of a few hundred feet. Security was an afterthought -- nobody had predicted war-driving, for instance -- and performance can be spotty.

WiFi isn't going away. Local access points will continue to exist in your local coffee shop, library, and hotel, in part because the price of the technology has become dirt cheap. However, a new network standard, WiMAX -- more rigorously defined as the IEEE 802.16 WirelessMAN Standard -- is gaining a lot of attention. WiMAX addresses the "first-mile/last-mile" connection in wireless metropolitan area networks -- so you can get online from almost anyplace in downtown. According to the IEEE, the standard focuses on the efficient use of bandwidth between 10 and 66 GHz (the 2 to 11 GHz region with PMP and optional Mesh topologies by the end of 2002) and defines a medium access control (MAC) layer that supports multiple physical layer specifications customized for the frequency band of use.

Does all that make your eyes glaze over? Not to fear. Today, during a panel discussion held at the IEEE's International Performance Computing and Communications Conference (IPCCC) in Mesa, Arizona, experts explained the details of WiMAX, along with the issues of its standards, performance, applications, and implications. That's not bad for 45 minutes.

As Mark Goldstein, president of International Research Center explained, the WiMAX standard has broad bandwidth (up to 135 megabits per second (MBit/s)); it supports multiple services simultaneously with full quality of service (QoS) (IPv4, IPv6, ATM, Ethernet, etc.); it has adaptive modulation (that is, the bandwidth will automatically rise to a level that the signal strength supports); and security is built-in from the get-go.

Those capabilities are becoming more important as cities and communities are taking it upon themselves to provide access across town. A local example is Tempe, Arizona, which recently unveiled its wireless network, covering the entire city (40 square miles). The neighboring cities of Chandler and Gilbert are also deploying wireless networks in their communities; upon completion, the single wireless network will have a 187 square mile footprint. Connecting Tempe alone, however, requires 400 access points.

You don't need to think that big; covering your corporate campus might be enough. WiMAX is attempting to provide that answer, with a radius of 35 miles (though Goldstein says, "Your mileage may vary"). That's far better than 300 feet, and it requires far fewer wireless hot spots to be installed and maintained.

WiMAX isn't going to take over overnight, says Goldstein. The standards committee defines four levels of user mobility, and WiMAX isn't quite up to delivering it at the top end. (Mind you, neither is any other technology.) So you can't expect to get in your car and drive across the country with uninterrupted Internet access, at least not this week; the technology has to develop ways to manage optimized make-before-break hand-overs before that happens. The current specification of the technology is on user nomadicity -- movement from one stationary position to another. That is, they expect you to sit down for a spell, first in your chair in the coffee shop, then packing up and heading to the library. There are plenty of challenges even at that level of service, including DSL-like service from different "points of attachment," user authentication, and multi-operator roaming. Later revisions of the 802.16 spec, starting with 802.16e, will address portability and full mobility.

Nonetheless, Goldstein maintains, the current definition is enough to support a small community. That can help a business area such as the Scottsdale Airpark (where 50,000 people work, today). However, it has even more implications in supporting communities where the "last mile" problem has been insurmountable for traditional telco providers: rural areas, Indian reservations, and third-world countries. For example, pointed out Todd Blackwood, IT Development Manager at the University of Advancing Technology, 25% of the state of Arizona has no broadband Internet infrastructure today. (Lots of the Navajo reservation has no phone service, either.)

This new technology may encourage new roles in the wireless landscape, says Goldstein, from the re-emergence of Wireless ISPs (WISPs) to new assumptions in regard to a user's default bandwidth. It will certainly create new opportunities for new vendors, but big players are already paying attention -- particularly the companies providing cellular access. As Disney and ESPN are increasingly wanting to deliver high-bandwidth content to mobile users, the wireless telecom community is motivated to find new ways to make it happen.

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