802.11n: Morphing to meet new demands

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Michael Kassner

Published: 11 Jun 2008 12:05 BST

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...trying to determine what 802.11n will eventually look like, since it appears that ratification of 802.11n will not take place until mid-2009.

Putting that nebulous challenge aside for a moment, developers also have other real-world demands to deal with: emerging applications and technology, working in hybrid networks with legacy 802.11 equipment, improved performance in an ever-more crowded RF environment, and trying to convince the public that now is the right time to buy 802.11n equipment. Definitely enough to think about.

One area that will become extremely important to equipment developers is the use of 'metamaterial' antennas. This technology has the potential to revolutionise microwave RF propagation. Antennas using metamaterial technology can bend RF waves more than antennas using present day technology, which results in smaller antenna systems.

Being smaller in size allows the use of more antennas in a smaller space, creating conditions for improved RF reception and transmission. Antennas using metamaterial technology also have the capacity to transmit on either the 2.4GHz or 5GHz bands; they can be set to cover selected horizontal sector coordinates and, through co-ordination from the chipset, determine and use the optimal RF characteristics for a specific remote client.

2008's controversy
The big debate of 2008 will be whether to start using 802.11n equipment even though the amendment is not ratified. There are numerous well-written articles making points for either side.

Two of the better articles are written by Joanie Wexler, and published by Network World. Part one emphasises the opinion of Chris Kozup, a Cisco senior manager.

Kozup offers his perception of the relationship between IEEE specifications and Wi-Fi certification: "The definition of 'standard' includes consistency and interoperability — which are more a function of Wi-Fi certification than IEEE specification.

"Consider briefly the relationship of the original 802.11b to Wi-Fi, 802.11i to WPA2 and 802.11e to WMM. Businesses don't deploy an IEEE specification; rather, a standard that guarantees interoperability. The same rings true for 802.11n. While not yet ratified, the 802.11n draft 2.0 has already become a de facto standard thanks to Wi-Fi certification and product development momentum."

Part two presents an opinion by Joanne Lenno from Nortel's WLAN marketing group.

Lenno is a proponent of the 'wait and see' attitude and makes several points about why this maybe the best approach: "There are infrastructure concerns. If the throughput benefits of 802.11n are to be realised, the WLAN architecture must be able to support higher traffic volumes.

"Edge switching capacity and switching power also need to withstand increasing requirements. Without GigE, APs generating around 100Mbps will be artificially constrained. And, today’s 802.3af PoE can’t supply enough juice for maximum data rates with MIMO. The better fit will be with the coming 802.3at [IEEE PoE Plus standard]."

Final thoughts
My personal take is that 802.11n should be considered for each specific situation and not make all encompassing generalised decisions. I have set up several point-to-point links recently using 802.11 equipment.

During initial testing, I determined that the point-to-point links would not be possible if I had to use legacy 802.11 equipment. After further testing, I found that 802.11n equipment did not have the same throughput and RF environmental issues, allowing the successful setup of the point to point links. Sure, the equipment is Draft 2 and maybe out of spec within a year, but the existing equipment filled a very valuable need that was not financially or technologically feasible any other way.

Credit: 802.11n equipment is morphing to meet new demands from TechRepublic.com

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