Wireless Networking: Faster! Farther!

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The Realities of MIMO

Linksys Wireless-G with SRX.
Linksys Wireless-G with SRX.
There are a few things to bear in mind if you're considering upgrading to MIMO gear. First, these items can cost more than twice as much as their previous-generation counterparts. Second, most MIMO clients today are for notebooks, and there are no MIMO peripherals.

Third, speed gains will apply only to data transfers that occur within a local area network; they won't boost performance for Internet-related activities. Most broadband connections top out at a couple of megabits per second, a speed that a slow 802.11b network can match.

Fourth, streaming video, especially full-screen high-definition video, is apt to be a hit-or-miss experience. At close range, you might have the 19 mbps or so that high-definition TV requires, but you'll likely experience stutter if there's other activity on the network. A good streaming-media experience is likelier for DVDs, music, standard-definition TV, and Voice-over-IP content, none of which demands a throughput of greater than 10 mbps.

Finally, today's MIMO technologies aren't linked to a standard and won't be upgradable to the upcoming 802.11n standard when it emerges. Because vendors use different proprietary technologies, boosts in speed and range aren't fully available on networks that include equipment from different vendors or from the same vendor's older lines.

That may sound like a fatal flaw, but in reality things aren't so bad. All of the products we tested are compatible with existing 802.11g and 802.11b equipment--and with each other in 802.11g mode. And their multiple antennas help them deliver at least some performance benefits on networks populated with legacy equipment.

True 802.11n products are unlikely to appear for another year. But since the eventual 802.11n standard will be backward-compatible with 802.11g, current MIMO products and future 802.11n products will work together. Though the MIMO products may produce only 802.11g speeds, they shouldn't degrade the performance of future 802.11n products.

Quality of Service (QoS)

Photograph: Kevin Candland
The more devices you have on your network, the more obviously they'll compete for bandwidth, and the likelier an attempt to e-mail a large digital photo will be to affect a coworker's VoIP call.

Quality-of-service (QoS) technologies let you establish priorities for concurrent network activities--specifying, for example, that VoIP calls should never be interrupted by other types of traffic. While businesses and consumers wait for the IEEE to ratify a QoS standard (802.11e), a proprietary QoS technology from Ubicom called StreamEngine has emerged. It's available now in Hawking's $106 HBB1 Broadband Booster and will be coming soon in D-Link's Broadband Internet/VoIP Accelerator (the product's price has yet to be determined).

Ubicom says that, by default, StreamEngine gives VoIP the highest priority, followed by gaming traffic, streaming video, and file sharing. Users can set their own priorities, however. In a future issue of PC World, we'll examine whether Ubicom's QoS delivers.

--Narasu Rebbapragada

At a Glance
  • Belkin F5D8230-4 Wireless Pre-N Broadband Router

  • D-Link Super G MIMO Wireless Router

  • Linksys by Cisco Wireless-G Broadband Router with SRX - WRT54GX

  • Netgear Pre-N Wireless Router

  • Netgear WPN824 RangeMax Wireless Router

  • US Robotics Wireless MAXg Router with integrated USB Print Server

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