Fixed Wireless Equipment

Dragonwave Sees a Backhaul Future in 24 GHz

24 GHz spectrum is now available for point to point deployments only—which is great, because that's exactly what ISPs need it for.

by Alex Goldman ISP-Planet Associate Editor [June 27, 2003]

It's the end of June, and this month, DragonWave has achieved a lot. It announced that its 24 GHz product was the first to gain FCC approval—and has also announced some ISP customers. Erik Boch, CTO and vice president of engineering at Dragonwave, explained that FCC approval of commercial use of 24 GHz spectrum has been urged for a long time.

"About two years ago, the FCC was petitioned to open an Industrial, Scientific, and Medical band to more broad commercial use," Boch said. "The ISM bands were set aside to protect special equipment from what happens in the 5.8 GHz and 2.4 GHz bands, with interference from common household appliances such as handyphones, microwave ovens, and garage door openers. The FCC decided to allow only highly focused point to point microwave links. The group that lobbied for this is also lobbying for the upcoming RSS 210 regulations in Canada and is lobbying for similar regulations in Europe."

Boch says the technology gives ISPs the benefits of licensed spectrum (no interference) without actually having to license spectrum. He expects it will be most useful in the one network element that tolerates interference the least—backhaul. Other uses suggested by Boch include demanding customers such as schools. "Once you get beyond a few Mbps, what do you do," he asks. "You're buying DS-3s if you're wireline, which are hellishly expensive, or fiber optics, which are even more expensive, or you're trying multipoint wireless, but you're not getting the speeds you need."

He claims that interference is even present in the most rural of areas (a claim that is somewhat self-serving because he has the first FCC approved solution to get around it). He says, "a lot of DragonWave business comes from failed backbone deployments in unlicensed 5.8 GHz spectrum, especially in areas where you wouldn't expect a problem, such as one village with 10 buildings, but one person is using a powerful 5.8 GHz product."

He says ISPs can also benefit from growing concerns about backup systems. "Companies want backups that they won't have to pay for when they're not in use. If there's no license fee, you're not paying to maintain them. But they need a solution like ours that they can rely on when they need it."

He points out that users of cellular networks are accustomed to handling coverage problems. "If you're using a cell phone and you step into an elevator, you're not surprised that you've lost the signal. You fix the problem by stepping outside. You can do that with mobile networks. You cannot do that with fixed wireless networks. If you want to move, you're looking into negotiating with landlords, climbing towers or rooftops—you're looking at a lot of work. Fixed wireless UNII is not perfect, but it does have a place—indoors. I use it indoors on LANs every day."

Towering over the RBOCs
We spoke to one of DragonWave's 24 GHz ISP customers. TowerStream provides wireless broadband to business customers in major cities for about one-half the price of a comparable T-1.

Jeff Thompson, founder and president of the company, said, "we've been using the new DragonWave product for a couple of months. We use it in part of the core network for redundancy and additional capacity."

Thompson explained that TowerStream's network is all wireless, and that every wireless backbone connection is redundant.

Asked whether 24 GHz service is affected by weather, he pointed out that 2003 in the Northeast U.S. has been a perfect test case. "We've had only five weekends without either rain or snow. You would start seeing weather effects at 38 GHz (it has to do with the size of the sine wave) but not at 24 GHz. We have a 99.99 uptime SLA."

According to Thompson, big cities such as Boston and New York already have many point to point 5.8 GHz links, and the spectrum is getting crowded. The company owns some 18 GHz spectrum licenses, and uses equipment from Ceragon and DMC Stratix for specific applications, but would prefer to have unlicensed spectrum available because it's cheaper. The company does still use 5.8 GHz gear, much of it from Proxim, but the 24 GHz DragonWave equipment will give it an unlicensed option as well.

Some of TowerStream's biggest Boston customers are universities. He says, "we've got 14 universities at DS-3 or higher. The Berkeley College of Music is a high bandwidth customer, for example."

Thompson notes that while his network can deliver granular increments of Mbps, his customers, accustomed to dealing with the phone company, prefer to buy T-1s and T-3s and DS-3s—they also like buying them from TowerStream at half the price. "And," Thompson notes proudly, "customers accustomed to dealing with the phone company are shocked at how fast we can deploy."

—End