Stepping Up To 28 GHz

Grown weary of the interference headaches created by sharing unlicensed 2.4
or 5.8 GHz spectrum with other wireless Internet service providers? We found one
WISP that’s cured its UNII-band headaches by stepping up to operating in
licensed 28 GHz spectrum.


When Quad-Cities Online of Moline, Ill. ran into
interference on 5.8 GHz UNII wireless point-to-point backhaul links, the company
searched for other solutions. With about 6,000 broadband subscribers and a
publishing company behind it, the company had more resources than the average
WISP, including an LMDS license for the 28 GHz
band that it was not using.

Enter DragonWave, Inc., based in Ottawa,
Canada. DragonWave was able to supply Quad-Cities with its AirPair lineup, a
wireless solution that provides point-to-point links at 100 Mbps in both
directions (full duplex) and
operates anywhere in 18 GHz to 36 GHz spectrum. Since 802.11a has a maximum
speed of 54 Mbps, this roughly doubles the capacity of the backbone, before
allowing for the performance improvements gained through reducing interference.

DragonWave is not the only manufacturer in this area. But Erik Boch,
DragonWave CTO, claims that the company’s networking and manufacturing expertise
put its products over the competition.

“We started with a low cost manufacturing process. While our competitors were
hand-tuning their radios in the factory, we figured out a no touch high volume
manufacturing process that enabled us to establish partnerships worldwide to
sell our product,” says Boch. “This was important because, initially, LMDS was
not as popular in North America as it was internationally.”

“Another advantage,” notes Ken Davison, vice president of marketing and sales
at DragonWave, “is that we use a conventional surface mount so that the inputs
look just like a PBX or router.”

“The idea,” adds Boch, “is that setup should be really simplejust plug in
the RJ-45 Ethernet cable and
go.”

Of course, there are costs involved with licensed spectrum. Obtaining a
license is a process that can cost more than $750,000. At the time licenses were
issued, the FCC structured the rules to make it difficult for local cable and
telephone companies to acquire LMDS licenses. Officials noted that “given enough
market power, [they] could either warehouse the LMDS license to forestall a
third party from coming in and competing, or could raise the price of both
services they offer.” Therefore, the FCC divided the nation into 493 regions,
offering licenses within each region.

When LMDS licenses were sold, 38 Mbps was the maximum throughput of most
available systems. Although LMDS has always promised gigabit speeds, obtaining
those speeds requires a significant chunk of spectrum. Boch noted that
DragonWave is “able to get between 3 and 5 bits per Hertz of spectrum, so when a
customer has a 50 MHz band, we can reach up to 250 Mbps in total.”

The FCC is interested in allowing a secondary market in LMDS licenses to
develop, but although the FCC has considered allowing WISPs to trade and lease
LMDS licenses in a Notice of Proposed Rulemaking (NPRM), as far as we know, it
has not yet actually allowed any trades.

Davison is optimistic. He expects WISPs to deliver an ever larger bundle of
services and expects DragonWave to capitalize on WISPs’ rising bandwidth needs.
He says, “we built our product to run at the high end of the bandwidth curve.
WISPs can use it to serve VoIP, video,
and mixed data, and our antenna is compatible with a router’s QoS and traffic shaping
commands.”

The AirPair product features:


  • RJ-45 in and out
  • Supports 18 GHz, 23 GHz, 28 GHz, 32 GHz, and 38 GHz
  • Channel widths: 25 MHz, 50 MHz, 28 MHz, and 56 MHz
  • AC powered (DC option)
  • Uses in-based SNMP management, with an 802.1q tagged VLAN option
  • Comes with an optical sighting mount and radio-assisted alignment
  • Designed for outdoor use

The DragonWave radios will be field upgradable when upgrades are available,
to speeds of 250 Mbps in both directions or even to gigabit speeds. The company
claims its products routinely reach 15 km (over 9 miles) and that free space
optic (FSO) competition is good only for short links of less than 1 mile (but
FSO manufacturers claim they can reach farther on fog-free days).

This is new technology, so proceed carefully and investigate thoroughly.
WISPs should examine the licensed spectrum option because it could enable rural
and suburban WISPs to build their own wireless backhauls, significantly saving
dollars that would otherwise go to the local telco.

Pricing and availability

DragonWave’s AirPair
100 is available now.

For less than $30,000, the company sells one link (a pair of point-to-point
radios) with system, antenna, and cable. At 100 Mbps, the product is able to
form a part of most networks, especially Ethernet

Reprinted from ISP-Planet.

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