New fast Wi-Fi products spark MIMO definition war

TechWorld.com - NetGear Inc. has launched wireless LAN kit which uses the multiple input/multiple output (MIMO) multiple antenna technology to get faster speeds, and sparked a debate as to what MIMO means. Meanwhile, MIMO is cropping up in the wide area, as a future direction for mobile phones beyond 3G.

NetGear's RangeMax products, using MIMO to get faster speeds, better range and better coverage, will arrive in the U.K. in April.

However, NetGear is using chips from Video54, and that has sparked an angry response from Airgo Networks Inc. -- whose chips drive all other current MIMO products -- which claims the products are not really MIMO at all. The argument could become important as the IEEE works on a next-generation Wi-Fi standard, 802.11n, which will use MIMO.

While Airgo makes the whole chip set for the products used by Belkin Corp. and Cisco-Linksys LLP, Netgear is using its customary Atheros chips: Video54's BeamFlex chips are an overlay, which can be used to add MIMO to other vendors' chips. It uses seven independent internal antennas, which can be turned on and off, giving 128 routing patterns.

NetGear claims that the Video54 technology gives it a range of 495 feet and throughput of up to 48Mbit/sec. real throughput (which is more than the real throughput of products claiming peak rates of 54Mbit/sec. or 108Mbit/sec.).

Airgo says this isn't true MIMO (and not just because it has the trademark for "True MIMO"), according to Wi-Fi Planet. Airgo sends two radio signals in one channel -- a technique called "spatial multiplexing" which is included in the WWISE proposal for the 802.11n.

To confuse things -- and perhaps ensure a limit to the complaining, Netgear is actually an Airgo customer, using True MIMO for kit that it sells in Japan, because of local regulations

Whatever the outcome in the LAN, MIMO may be set for greatness. This week Nortel Networks Corp. is demonstrating the use of MIMO -- as well as the Orthogonal Frequency Division Multiplexing (OFDM) techniques used by Wi-Fi and WiMax -- in making mobile phone networks beyond 3G and that can support twice as many subscribers. "We believe that OFDM and MIMO will be vital to service provider success and will be the foundation of future wireless broadband networks," said John Hoadley, Nortel's vice president of carrier networks.

Nortel has shown peak data rates at 37Mbit/sec. over a standard 5-MHz PCS band that models real conditions on the cellular network. The demonstration, at Nortel's Ottawa labs, using both MIMO and OFDM, to transfera 128MB file in 30 seconds.

Reprinted with permission from

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