Stretching wireless LANs to the limit

Envision a wireless LAN with:

• Nearly limitless range.
• Two or more times the throughput of today's wireless LANs.
• The smarts to match bandwidth to applications.
• Bulletproof security.

This might not be as far off as you think, if even a fraction of the wireless technologies being cooked up make their way into products and services.

Everyone from network giants such as Cisco  to venture-funded start-ups still in hiding are spending heavily in an effort to grab a big or bigger slice of what Gartner says will be a $2.8 billion market by 2003.

During the first half of the year, 135 privately held wireless companies raised $1.4 billion in venture capital, with about half of it going to infrastructure vendors, according to Growthink Research. The market research firm estimates that one in every 10 venture capital dollars spent through June went into the wireless market and that about the same was true during the corresponding period last year.

"As an investor, I focus on cost per bit," says Chris Brookfield, general partner with Northwest Venture Associates. "In wireless LANs, it is incredibly inexpensive to move data, compared with other wireless technologies like [Cellular Digital Packet Data], [General Packet Radio Service] and 3G."

Brookfield sees the wireless LAN market as a hotbed of innovation. "All of my investments [in wireless] focus on how to give users access to their applications wherever they are, whenever they want," he says. "Then, they find new ways to be productive. We've seen that over and over again in cell phones, e-mail and other things."

Here's a sampling of developments that could be coming to wireless LANs.

Greater reach

In today's wireless LANs, with power limited by the Federal Communications Commission, performance drops markedly as the distance between access points and adapter cards increases. Under the best conditions, 802.11b has a range of about 300 feet; 802.11a goes about one-third of that. At maximum distances, throughput can drop from the typical actual throughput of 5M to 7M bit/sec for 802.11b and 18M to 21M bit/sec for 802.11a to mere kilobits per second if loads of users are linked to one access point.

While vendors are trying to address the distance issue through creation of advanced silicon and better antenna designs, one of the more intriguing solutions is the use of mesh networks that provide a new way for wireless LAN radios to interact.

Wireless LANs today are based on client adapter cards that wirelessly link to an access point, which is then wired into the corporate LAN. Technically, 802.11 clients can create ad hoc connections to one another, but this isn't widely used.

MeshNetworks is one of several companies building software to create a mesh instead of a hierarchical wireless LAN (others include SkyPilot, Ember and CoWave Networks). The software loads on the wireless adapter card and turns every adapter into a repeater-router, instead of an endpoint looking for an access point.

This means your wireless PDA can hop through someone else's wireless laptop, or through several, to finally reach an access point to the corporate network.