802.11n: A Prison of Promises?

Yes, 2008 is the year for 802.11n. But while every wireless and networking vendor on the planet has the same access to the same 802.11n silicon, what is going to differentiate one system from another?

802.11n systems will be differentiated based on technical advances that add value to these chipsets.

Unlike the previous 802.11 a/b/g standards, 802.11n comes with a whole host of new knobs (read controllable system parameters such as physical layer data rate, frequency of operation, radio noise rejection, etc.) that need to be automatically tuned and optimized to realize the technology's full potential.

Technical advances, such as smart antenna arrays and dynamic quality of service engines, will help to control and focus signal propagation, mitigate and nullify interference, and automatically tune and optimize all these new parameters and are essential to making 802.11n live up to the hype. 

Consider the Paris to Dakar Rally. The winner of this race is the one that is capable of handling the harsh environment and road conditions along the way - even though all participating cars must meet the same standards in terms of maximum engine size. Similarly 802.11n products that better adjust to a changing Wi-Fi environment, such as dealing with interference and dynamically managing quality of service will out perform others.

The 802.11n standard allows for a range of modulation and coding schemes chosen dynamically based on environmental conditions, delivering from 6.5 mbps to 600 mbps of bandwidth to the end user. It also provides for almost an order of magnitude more data rates from which to choose.

But unlike the 802.11 b/g standard, higher throughput is dependent on the ability of the Wi-Fi infrastructure to use multiple spatial streams and 40 MHz channels in a given environment.

Wi-Fi beam forming/steering technology better adjusts to environmental conditions and as such will contribute to increased performance relative to other 802.11n products.  Here's how:

• It increases the likelihood that 40MHz channels can be used (instead of 20MHz channels).
  Other 802.11n products would be able to use wider channels but only when they are free of interference (and when ISN'T there interference?). Adaptive smart antenna technology mitigates undesired interference by continuously choosing the best and most optimum Wi-Fi beam pattern based on where the receiver is located. In turn it can use a wider channel in more situations, even if there is some interference in the area.  This means higher and more consistent throughput.

• It increases the likelihood that multiple spatial streams can be used (instead of a single stream).
  All of today's 802.11n products (consumer OR enterprise) rely on the spatial diversity provided by simple omni antennas mounted next to each other in a very similar form. Products that take advantage of diverse beam forming and steering techniques (leveraging both horizontal and vertical antenna polarization) will be able to generate multiple streams have a much higher likelihood to be (decorrelated) better constructed at the receiver thereby resulting in a higher data rate.

With Smart Wi-Fi systems you effectively double the chance that higher data rates are used because of the ability to effectively guarantee the spatial multiplexing and channel bonding techniques that make 802.11n so fundamentally different. Controlling signal path selection, dynamically moving Wi-Fi signals to better paths on a per packet basis and automatically tuning software parameters that need to be optimized will deliver the best possible 802.11n performance.