802.11n set for final approval
- — 11 September, 2009 06:07
Sometime on Friday, at the sprawling Hyatt Regency hotel in New Brunswick, N.J., an IEEE group called the Standards Board is expected to approve the 802.11n wireless LAN standard.
For some enterprises, that’s the green light to start deploying the high-throughput WLAN standard, which offers five- to eight-times the performance of existing 802.11bg and 11a equipment. For others, the milestone will be anticlimactic, since they’ve been using gear based on the draft 2.0 of the specification, finalized and little changed since early 2007.
Both groups will be relying on 11n products certified by the Wi-Fi Alliance as interoperable and standards compliant. The WFA, an industry group that created the Wi-Fi brand to popularize the wireless technology, plans to make only minor changes in its testing program, to address some optional features that have been added to the 802.11n specification.
“The core interoperability is totally preserved with the [existing] draft certification program,” says Kelly Davis-Felner, the WFA’s marketing director. “We’re adding a handful of new features, all of them options under the 11n standard.” Existing draft-11n products should work seamlessly with future products based on the final standard. No existing products will have to be retested in the updated certification program.
The optional features, chosen because WFA members have expressed interest in rolling them out in the coming months, include:
• Packet aggregation: Aggregating some packets can improve transmission efficiency.
• Testing devices that support three spatial streams (known as 3x3 MIMO): WFA currently certifies only 2x2 configurations; the addition of a third data stream will boost the data rate and sustain higher throughput at longer distances
• 2.4GHz channel coexistence: In the 2.4 band, if the 11n radio detects legacy Wi-Fi devices, it won’t allow two 20 MHz channels to be bonded together for higher throughput, because doing so might cause interference for those devices.
• Space Time Block Coding (STBC): This technique can improve transmission redundancy and reliability, especially for 11n clients that use just one antenna.
The WFA’s updated test program will launch on September 30, Davis-Felner says.
In two years, WFA has certified just over 700 11n products. As of last July, about 45% of these were computers and adapters, about 30% were consumer or home networking equipment, and about 15% were enterprise devices. The newest tech fad: Blu-ray players with 11n radios.
The alliance cites data from market researcher ABI Research forecasting 11n shipments to rise to 45% of all 802.11 shipments in 2009, and 60% in 2012. Shipments of 11b/g equipment are falling off, and 11abg products are at present holding steady, according to Davis-Felner.
Within months of the draft 2.0 vote in early 2007 by the IEEE task group, a pack of vendors were unveiling wireless products based on it. That trend accelerated when WFA launched its certification testing in June of that year; in short order, 30 draft-11n products had been stamped with the Wi-Fi logo.