The most advanced wireless local-area network (WLAN) standard, 802.11n, has been a part of the business and consumer landscape since 2007. During the past year, the focus has subtly shifted from the finalizing of the standard, which now is all but signed, sealed and delivered, to development of efficient and inexpensive real-world deployment procedures.

802.11n is growing quickly because it is far faster, flexible and robust than legacy 802.11 standards. It combines features such as multiple in, multiple out (MIMO) antennas – which use bits and pieces of multiple signal streams to create a superior final product – with channel bonding and directional antennas, says Cyrus Behroozi, the chief scientist for Tropos Networks.

Transporting these benefits in the real world, which is full of interference, random noise and other electronic annoyances that can neutralize 802.11n’s advantages, is not easy. The industry is now fully engaged in these issues, since it no longer has to worry about whether the standard will change. Standards setting takes years in even the best of circumstances – and the 802.11n process was extraordinarily messy. At this point, however, draft standard is in place and the industry knows that any changes will be minimal and achievable by firmware upgrades to deployed “draft N” products. This peace of mind goes a long way.

It is fascinating to watch as engineers, architects and others try to work 802.11n access points (APs) and endpoints – the quarterbacks and receivers on a wireless LAN football team – onto the field where the 802.11a, b and g junior varsity teams already are playing. The challenge is that that the radio frequency is a shared and limited resource. The bandwidth must be fairly divvied up to all comers, but in a way that doesn’t limit 802.11n’s main selling point, which is its speed.

It’s certainly doable. Indeed, Chris Kozup, the senior manager for Cisco’s Mobility Solutions, says that much of the existing infrastructure can be reused to support 802.11n. However, problems can emerge because the underlying foundation is not always solid.

“Many wireless LANs began as ad hoc networks, typically of an experimental or casual nature,” says Andrew Borg, a senior research analyst for Wireless and Mobility at the Aberdeen Group. “There is a maturing of the wireless LAN ecosystem and what is being transported without a corresponding evaluation of deployment practices,” he says. “One might think that if you throw up a few ‘N’ APs, everything will be fine. Sorry, that is not the way it works.”

New Demands

These networks, whether or not they were properly planned, are being asked to accommodate a lot of different and more exacting protocols. Luckily, there are multiple tools, both baked into the standard and in broader network architecture, to bring to bear on the problem. “We are moving from an era of defining the theoretical performance of the devices to actually thinking of how to approach that in reality,” says Mike Tennefoss, the head of strategic marketing for Aruba Networks. “There are different methodologies to do that. Some have to do with the operation of the wireless LAN itself … and some with the behavior of the client.”

The most basic level of any connection is the connectivity between senders and receivers. This is known as the physical (or, in industry parlance, PHY) layer. In a wireless LAN, an AP grants the right to make a connection to the endpoint on a random basis. The idea is that over time, the laws of statistics will result in every station getting about the same opportunity.

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