Wi-Fi Alliance Begins Wireless-N Testing
By Joseph Palenchar -- TWICE, 9/30/2009
Austin, Texas - The Wi-Fi Alliance launched a testing program to certify the interoperability of IEEE 802.11n wireless-networking products, which are eligible to display the new "Wi-Fi Certified n" logo and one of two optional tag lines depending on tested performance levels.
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 The Wi-Fi Alliance will use these logos to certify the interoperability of wireless-network devices using the finalized IEEE 802.11n standard. |
The logos will also indicate whether an n-certified product is backward compatible with devices conforming to the wireless 802.11 a, b or g standards. All n-certified products must be compatible with at least one of the legacy standards under alliance certification criteria.
Wireless-network products sporting the n logos will begin appearing in stores in the coming weeks now that the IEEE has finalized the 2.4/5GHz-band standard, said to deliver up to 10 times the datarate of 802.11g/a at up to twice the distance. The technology enables reliable wireless-HD video transmission simultaneously with multiple data transfers and VoIP phone calls, the alliance said.
Roughly 700 products worldwide have already been certified by the alliance since June 2007 as meeting the IEEE's interim draft-n standard, and without undergoing a retest, these products will be allowed to carry the basic "Wi-Fi Certified n" logo without optional tag lines, said alliance executive director Edgar Figueroa. The products can be promoted immediately on their manufacturers' web sites and on the alliance web site as conforming to the final 802.11n standard, and the logo can appear on the product's packaging and literature as soon as logistics issues allow. A basic "Wi-Fi Certified n" logo will appear in stores within weeks on the packaging of some draft-n products because suppliers, aware of the coming logo change, will paste stickers bearing the new logo over existing packaging, Figueroa said.
Beginning Sept. 30, draft-n products and new products that pass the alliance's new wireless-n tests will be able to display the new logo with one of two optional tag lines - "dual stream n" or "multi-stream n" - depending upon the maximum data rates that they could potentially deliver. The dual stream tagline indicates a potential maximum data rate up to about 250Mbps, or up to five times than 802.11 g/a, and the multi-stream tagline indicates a potential maximum data rate up to 10 times faster, or around 600Mbps.
In wireless access points, dual-stream n models simultaneously send or receive the same data in two separate (spatial) streams within the same channel. The higher speed "multi-stream n" tagline indicates an access point offering three or four simultaneous streams in either direction. Only multi-stream access points with four transmit and four receive channels, however, could potentially deliver the maximum 600Mbps in either direction.
Both taglines also indicate that a device includes three other performance-enhancing technologies, including packet aggregation to send more data on a packet.
Client devices will also be certified as "dual stream n" or "multi-stream n," but here, too, suppliers need not offer the maximum number of send and receive channels needed to deliver the maximum data rate that each designation could offer.
In another caveat to the logo standards, only products operating in the 5GHz band will get dual stream or multi-stream designations. Certified-n products can operate in the 2.4GHz band, in the 5GHz band, or in both bands simultaneously, but maximum data rates under the dual stream and multi-stream designations are much more likely to be achieved in the 5GHz band, said Sarah Morris the alliance's senior marketing manager. That's because the 5GHz band is less crowded and wider, enabling it to accommodate more of the optional 40MHz-wide channels that are capable of delivering the highest data rates.
To help consumers sort out these caveats, the alliance has developed an optional matrix that can be placed on packaging and literature to include such information as frequency bands used and number of spatial streams supported in each band.
Companies that offer downloadable dual stream and multi-stream upgrades for draft-n products will be able to promote the upgrades as certified upgrades after they have been tested by the alliance.
More background on the new n standard is available at www.11nbasics.org.
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