The Institute for Electrical and Electronics Engineers (IEEE) announced this month its High Throughput Task Group voted to change its 802.11n (Wireless LAN Medium Access Control and Physical Layer Specifications: Enhancements for Higher Throughput), which is expected to be finalized next year, to allow wireless connection speeds of up to 600 Mbps.
The IEEE 802.11g standard allows transfer rates of up to 54 Mbps in the 2.4 GHz band, while 802.11b – which has been available since 1999 – allows 11 Mbps in the same band. Both 802.11b and g have ranges of up to 100 metres, but the IEEE is vague on the possible range of 802.11n.
The chairman of the IEEE 802.11n task group, Bruce Kraemer, would not answer questions from Computing Canada on the proposed standard. In an e-mail replying to CC’s questions, IEEE spokeswoman Nancy Vogtli would only say the range of 802.11n “would vary widely, depending on implementation.”
Vogtli said the data transfer rate “should decrease” as the distance from a client to an access point increases.
But offering 600 Mbps over a wireless connection is difficult, according to an executive at a components manufacturer that plans to manufacture 802.11n products for access point and PC card manufacturers.
“That 600 megabits per second is actually technically an optional mode,” said Dave Borison, director of product management for Palo Alto, Calif.-based Airgo Networks Inc., which claims its True multiple input multiple output (MIMO) Gen 3 chipset allows transfer rates of up to 240 Mbps. “To get to that 600 Mbps is very complex.”
That’s because MIMO allows antennas to divide data streams into several different streams over the same frequency at the same time.
“The way MIMO works with today’s products, is instead of sending one transmission over the air, you’re using two radios and sending two transmissions at the same time on the same channel,” Borison said. “To get to those 600 Mbps link rates, you’ll need three spatial streams.”
Corporations will wait
Although the initial markets for 802.11n will be consumer and small office, Borison said corporate IT departments could eventually use 802.11n products instead of 10/100 Mbps cabling for their office LANs.
“In an office environment today – you can cover properly a small office with maybe a dozen or two users and get better performance on a wireless network than with a wired network.”
802.11n could be used to connect networks at two separate sites within the same city, said Greg Collins, senior director for wireless LAN research at the Dell’Oro group, a Redwood City, Calif.-based market research firm.
Dell’Oro predicts network equipment manufacturers will ship US$1 billion worth of 802.11n gear in 2007, but most of that will be to consumers who aren’t concerned about interoperability.
“They’re less concerned about interoperability and things like that, whereas an enterprise wants interoperability,” he said. “If they’re going to make a big investment, they don’t want to have to rip it out in a year or two years because it’s not compatible with anything.”
Corporations will not start buying the equipment until 2008, when PC manufacturers start shipping notebooks with 802.11n cards, Collins said, adding by 2009, “the transition will be pretty quick” from 802.11g to 802.11n.
Wireless equipment using 802.11 protocols are typically used in Wi-Fi hotspots, corporate LANs and by consumers connecting portable devices to a high-speed Internet gateway.
Service providers will be in on the game as well, taking advantage of the higher bandwidth to offer video services to consumers.
Collins predicts consumers will buy “pre-standard” 802.11n equipment next year, but corporate buyers will want to wait until the standard is ratified.
“They don’t want to have to rip it out” if it doesn’t comply the 802.11n specs, he said.
The 802.11n task group is currently considering proposals from three groups of vendors: TGn Sync, Worldwide Spectrum Efficiency and MITMOT.