Home Networks: New Technologies Vie to Carry Video
The new MIMO routers may do a great job of increasing the range of a Wi-Fi network, but they won't necessarily solve the next big challenge for home networking: streaming high-definition video.
For that job, you need both adequate range and high throughput (at least 20 megabits per second for HD video)--a combination that may require a network built on wires that already exist in your house (namely, power lines or coaxial cables).
Products based on the HomePlug 1.0 standard for transmitting data over power lines have been around for three years or so and performed at least as well as 802.11b Wi-Fi gear in our tests (see "Just Plug It In: Networking Via Power Circuits"). But HomePlug 1.0 seems to have lost the network wars to Wi-Fi.
HomePlug advocates believe the technology's next generation may do better, however. Called HomePlug AV, it will theoretically provide a throughput of 200 mbps, which translates into real-world speeds of 70 to 120 mbps, says Andy Melder, senior vice president of HomePlug chip maker Intellon. The HomePlug AV spec should be ratified in the first quarter of this year, with products expected in early 2006. Principal backers, aside from Intellon, include Comcast, EarthLink, RadioShack, and Sharp.
Another camp argues that the best wire for moving video around your house is the one that already does it: the coaxial cable used by cable TV. The Multimedia over Coax Alliance, whose members include Cisco Systems, Comcast, EchoStar (owner of Dish Network), Panasonic, RadioShack, and Toshiba, expects to complete a spec by midyear, with products due by fall, says MoCA president Ladd Wardani. Theoretical maximum throughput will be 270 mbps; actual throughput, about 100 to 135 mbps.
Both power-line and coaxial networks would be immune to the cordless phone or microwave interference that can cripple Wi-Fi. But devices on the same circuit--a vacuum cleaner or a halogen lamp, for example--can interfere. HomePlug backers say they've found workarounds.
Coaxial networks are the least susceptible to interference, Wardani says, because the wires involved are available only for TV.
Intellon's Melder says that no single network standard is likely to emerge victorious from this competition. "The network of the future in the home is going to be a hybrid network," he says, with one or two systems for video and another for data.
Edward N. Albro
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