Wi-Fi Alliance updates Certified 802.11n program, intros shiny new logo

PC-World - The Wi-Fi Alliance is launching a certification program based on the completed IEEE 802.11n standard on Wednesday and looking toward a future peer-to-peer specification it is developing on its own.

Testing has now begun in the "Certified n" program, which succeeds the Wi-Fi Certified 802.11n draft 2.0 program that the industry group began two years ago. The testing begins with two labs but will expand to 13 locations within the next few weeks.

The 802.11n specification took so long to complete that in 2007 the Wi-Fi Alliance began certifying products for compliance with a draft version of the standard and interoperability with other draft-based equipment. The Institute of Electrical and Electronics Engineers finally formalized the standard earlier this month.


As it announced in July, the Wi-Fi Alliance isn't changing its fundamental test now that the standard is complete, so any product already certified under the draft version can use the new "Certified n" logo. But once a product has been modified, the vendor is expected to have it re-certified, as is the usual practice, said Kelly Davis-Felner, marketing director of the Wi-Fi Alliance.

The new program also adds certification for a few new capabilities. Equipment can be certified as "dual-stream" or "multi-stream" depending on whether it supports either two or three streams. Multiple streams, which can boost performance, can be created with the multiple antennas provided for in 802.11n. More than three streams are possible under 802.11n, but the Alliance is only testing for two or three at this time, Davis-Felner said.

The group has also set up testing for other optional features, including the following:

- packet aggregation, a technique designed to reduce the amount of overhead required for data transfers,

- "channel coexistence" measures, which allow a device to use two adjacent 20MHz channels in the 2.4GHz band without interfering with other networks,

- and space-time block coding, a mechanism for improving reliability, which prevents a client that can only use one spatial stream from slowing down a network that uses multiple streams.