Multiple In, Multiple Out, Multiple Standards
By Carlo Longino, Mon Jan 10 23:15:00 GMT 2005

MIMO technology is popping up in ultra-high-speed mobile networks coming out of research labs, but it's also quickly making its way into consumer Wi-Fi gear. But with the higher speeds come compatibility concerns.


Multiple-input, multiple-output systems use multiple antennas to essentially increase the speed of wireless transmissions. The system from Siemens' labs that hit 1Gbps as well as DoCoMo's 300Mbps test network both use the technology, and it's expected to be a part of forthcoming 4G standards.

MIMO is also expected to be a part of the upcoming 802.11n standard, in one form or another, but MIMO is already making its way into 802.11g consumer and enterprise Wi-Fi gear as companies look to eliminate dead spots and increase speeds. PC World says MIMO products it tested from one vendor showed speeds double that of standard 802.11g gear, with increased range. Much of this gear is being sold as "pre-n" equipment, though it could ultimately be incompatible with standardized products -- and like much of today's Wi-Fi gear that offers "enhanced g" speed rates, incompatible with other vendors' MIMO implementations.

Video was hot at last week's Consumer Electronics Show, and vendors say demand for wireless streaming video devices is driving the need for faster networks. But the rush to deliver pre-standard products based on proprietary enhancements could fragment and stall development of future standards. If companies focus on creating their own revisions to existing standards, they have little incentive to help design new ones -- leaving the market filled with equipment that's compatible only at its most basic functionalities.