Bridging the Long Last Mile

Back in 1999, Jim Williams, IT manager at Welch Packaging Group in Elkhart, Ind., found that a speedy, cost-effective wired connection to the Internet simply wasn't available. So, like people at hundreds of other small and midsize businesses, Williams turned to a fixed wireless technology to bridge that last mile between his business and the Internet.

Williams explored a range of services, including dial-up and a fractional T1 line, but found the former too slow and the latter too expensive. Finally, he elected to use a local Internet service provider that offers wireless access from cellular towers using the 11M bit/sec. 802.11b wireless LAN standard.

The service, from MicroVillage Internet Services in Mishawaka, Ind., operates in the 2.4-GHz frequency spectrum to link business users and consumers in a two-county area to an Internet backbone.

Elsewhere, companies are using other wireless technologies for last-mile connections, including Multichannel Multipoint Distribution Service (MMDS), which provides T1 speeds to users within 35 miles of a central tower; Local Multipoint Distribution Service (LMDS), which is faster than MMDS but limited to shorter distances; two-way satellite service; and through-the-air laser signals.

Dial-up Internet access via Digital Subscriber Line (DSL) wasn't an option for his company, Williams explains. "We were too far from the [central office] for DSL, and even a partial T1 was going to run us over $500 per month," he says.

"Wireless was cheaper," Williams says. "And it gave us more bandwidth [than the partial T1]."

Williams says he pays $450 a month for his service and is guaranteed a transfer rate of 128K bit/sec. But he notes that average throughput is much higher; he regularly gets burst speeds of up to 3.5M bit/sec.

Reliability was at first a little dicey, Williams says, because the 2.4-GHz signal must have a clear line of sight. But erecting an 80-foot tower solved the problem and provided the antenna platform for a wireless LAN based on Aironet technology from Cisco Systems Inc. The wireless LAN connects two other nearby packaging plants that Welch obtained when it acquired another company.

The fixed wireless setup uses unlicensed spectrum, which is a little risky because there are no regulations against interference from other devices, such as microwave ovens and portable phones, that use the same frequencies, says Lisa Pierce, an analyst at Giga Information Group Inc. in Cambridge, Mass. Still, MicroVillage officials say they haven't experienced any major interference problems.

Chris Brewer, MicroVillage's network operations manager, says he has one site that's seven and a half miles from the nearest tower, but he prefers to limit transmission distances to no more than four miles. The cost of installation is $400 for business customers.

Distance from the service provider's antenna is less of an issue for MMDS wireless users like Todd Gorman, operations manager at Gorman Uniform Service Inc., a uniform rental business in Houston. Gorman contracted with Sprint Corp. to provide MMDS broadband wireless to his business.

MMDS operates over a licensed wireless spectrum at 2.6 GHz, which was originally used by local wireless cable TV operators to send signals to subscribers' homes. The TV application, however, ultimately lost out to coaxial cable.

Now Sprint and WorldCom Inc. are using the 2.6-GHz spectrum to provide broadband wireless network connections. Sprint is the most aggressive in this sector, says analyst Lindsay Schroth at The Yankee Group in Boston. WorldCom seems to be waiting for Sprint to work out any kinks in the technology before it presses ahead, she says.

Sprint's MMDS service is now available in 14 large markets including Chicago, Denver and Phoenix, says the company's vice president of wireless operations, Cameron Rejali. A central MMDS antenna like the one Sprint has placed on top of the Sears Tower in Chicago can reach customers within a radius of 35 miles, Rejali says.

Gorman chose MMDS wireless even though he had access to DSL and T1 services. Why? "Sprint [wireless service] was the cheapest for the speeds we got," he says. The MMDS service, which Gorman says costs him $149 per month, is comparable in speed to a T1 line that Reston, Va.-based XO Communications Inc. priced at $700. Both have burst speeds of up to 1.5M bit/sec., Gorman says.

Wireless access was an even better deal than wired DSL, according to Gorman. He says the local telecommunications provider, Southwestern Bell Telephone Co., a unit of SBC Communications Inc. in San Antonio, wanted $300 to $400 a month to provide DSL lines. Gorman has been using the Sprint MMDS service for five months and says it's been very reliable, with one exception: The proxy server located between the uniform company's LAN hub and the Sprint MMDS modem has gone down a few times. "When that happens, I reset the IP addresses to restore the service," he explains.

Wireless at Wired Speeds

The higher the wireless frequency, the greater the bandwidth a given spectrum can accommodate. However, as frequency and bandwidth increase, transmission range decreases.

But in the case of Spirent Communications in Calabasas, Calif., a division of U.K.-based Spirent PLC, bandwidth, not distance, was the main issue when it came time to connect its main facility to another building a half-mile down the road. Tom Sommer, Spirent's network manager, says a DS3 private line would have provided the bandwidth his company needed between the two sites, but the $5,000-per-month fee would have blown his budget.

Instead, Sommer shelled out $18,000 for point-to-point wireless Ethernet equipment from Western Multiplex Corp. in Sunnyvale, Calif. The system runs over license-free spectrum in the 5.3-GHz range. At 45M bit/sec., the link is equivalent to the bandwidth of a DS3 for data, plus it has a separate channel for telephone services.

Certainly, Spirent's connection is plenty fast as wireless goes, but even higher wireless speeds are possible. The licensed 28-GHz spectrum, 90% of which is owned by XO Communications, can accommodate speeds of up to 622M bit/sec. for distances of three to five miles.

As for LMDS, a flurry of bankruptcies this year among LMDS service providers, including Winstar Communications, Teligent Inc. and Advanced Radio Telecom, has put a damper on that technology, says Pierce. While LMDS struggles for a footing in the U.S. market, analysts expect MMDS technology to advance under the auspices of Sprint and WorldCom.

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A Primer on Wireless Last-Mile Technologies


802.11b

Speed: 11M bit/sec.

Description:

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Line-of-site transmission of up to five miles

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Potential for interference from other unlicensed devices operating in the same spectrum

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No control over addition of new devices in the area that might cause interference

Multichannel Multipoint Distribution Service (MMDS)

Speed: 512K bit/sec. to 5M bit/sec.

Description:

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Line-of-site transmission of up to 35 miles

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Licensed spectrum; one provider per market

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Available in certain markets from Sprint and WorldCom


Local Multipoint Distribution Service (LMDS)

Speed: Up to 622M bit/sec.

Description:

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Line-of-site transmission of up four miles

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More susceptible than MMDS to weather disruptions, particularly rain


Laser

Speed: Up to 100M bit/sec.

Description:

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Line of site transmission of about 1,300 feet normally, but possibly more than a mile in clear, dry climates

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Point-to-point connections to the Internet

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Point-to-multipoint to connect buildings and then connect to the Internet

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Dense fog or snow can disrupt service

Low-cost Satellite

Speed: 300K-500K bit/sec. downstream;

60K-150K bit/sec. upstream

Description:

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Line-of-site of approximately 20 degrees above the horizon in the southern sky

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High latency

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Works in remote areas where no wireless-to-wired connectivity is available




























Copyright © 2001 IDG Communications, Inc.

  
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