Good, better, best. Anyone who's ever set foot in an electronics store--let alone designed or packaged consumer technology merchandise--understands this fundamental tenet of product marketing.
An entry-level product--the "good"--should provide a baseline, albeit unexciting, set of features. Compelling features not required for ground-floor operation are reserved to lure customers to spend more for the "better" and "best" products.
In the wireless-LAN arena, cultivating feature sets that preserve tiered product strategies has been a challenge. Aside from brief periods of technology transition, such as the emergence of 802.11g offerings six years ago, Wi-Fi products--like all standards-based merchandise--ultimately settle into "good" price points.
There have been attempts to carve out higher-priced niches for Wi-Fi, such as with off-standard modes that provided higher raw data rates or extended range at lower rates--provided you paired two products with chip sets from the same vendor. By and large, however, proprietary enhancements weren't effective at holding up the higher price points. So hardware vendors were left to differentiate their products with plastics and packaging, which meant they were in trouble (or they were Apple).
The IEEE set out to resolve the good-better-best dilemma as they defined the proposed 802.11n standard. Unlike previous WLAN generations, draft 802.11n provides for optional modes on top of required schemes, so vendors can provide different hardware configurations that attain distinct levels of performance.
One of the easiest knobs to turn is to double the channel width to 40 MHz, thereby effectively doubling the data rate. Though double-wide channels come with a power penalty that might require a costlier system design, there really aren't any additional component-related costs. As a result, 40-MHz channel support will likely become a baseline feature that won't command a premium.
Another alternative is to dial up the number of data streams. This is a key approach to differentiating 802.11n hardware, because multipath implementations require multiple radios and antennas. Draft 802.11n allows for up to four data streams. That, combined with 40-MHz channels, can take maximum raw data rates from 65 Mbits/second--just a hair's breadth better than the 54-Mbit/s raw performance delivered by 802.11g--all the way up to 600 Mbits/s.