802.11n

Wi-Fi Alliance Starts Testing Draft N

By Glenn Fleishman

They promised June—they delivered June—but I was expecting, well, certified devices, not certification testing: The Wi-Fi Alliance has been asserting since last year that they would have a certification program in place during second quarter 2007 to test Draft N (early 802.11n equipment) devices against Draft 2.0, an expected milestone in IEEE work on the standard. Today’s press release shows they met the mark, but I had naively assumed that there would certified devices on the market in June, too. Alas, not so. The certification program has begun, and new firmware and equipment will be out this summer. How soon, it’s unclear.

The Draft 2.0 compliant firmware that manufacturers have promised, and that chipmakers apparently completed months ago, will likely not be released for the majority of Wi-Fi devices with Draft N until certification is finished for that device in case things need to be fixed.

Draft 2.0 should improve interoperability among devices, and it adds three separate protection mechanism for the 2.4 GHz band to prevent N from using more spectrum than a comparable G device in the presence of other networks. In 5 GHz, where there’s much more “room,” only two of those mechanisms are needed, because interference is much less likely and easier to solve. (See “How Draft N Makes Nice with Neighbors,” an article I wrote after interviewing chipmakers that appeared 2007-02-16.)

Update: The Wi-Fi Alliance told me that certification could take as little as “hours,” and that 20 products were booked for testing on the first day of certification. That’s fine, but I’m interested in the cycle from certification to firmware release. I had really expected that certification results along with updated firmware would occur within the quarter, but I am just too darned optimistic.

Tim Higgins, meanwhile, is not very happy with his testing of pre-certification Draft 2.0 updates from D-Link. They don’t conform to his reasonable interpretation of the co-existence mechanisms for N and earlier B/G devices in the same frequency ranges.

source : wifinetnews.com