Fixed Wireless Equipment

Big Fat Freakin' Backhauls

A Tampa-based WISP needs high capacity radios for the core of its network and one company is delivering them.

by Alex Goldman ISP-Planet Managing Editor [January 18, 2005]

Today, Ashburton, UK and Waltham, Mass.-based Orthogon Systems announced the OS-Spectra radio.

Phil Bolt, CEO of Orthogon Systems says that the company added many new features to its Spectra product, differentiating it from the previous product, the Gemini. Nevertheless, the bandwidth offered by the Spectra is impressive. "The top data rate is 300 Mbps, less at long range," he says. The air rate is up to 400 Mbps.

Bolt says that another significant advantage of the Spectra is its spectrum footprint. The radio uses only 30 MHz of the 5725 to 5850 MHz band. Because the radio also incorporates the Gemini's ability to switch frequencies dynamically to avoid interference, this gives it plenty of room. The competition, he claims, has built radios that utilize the entire spectrum available, and would therefore be unable to avoid interference.

Bolt says that the company achieves better bandwidth through superior engineering. "QAM is the number of bits per signal," Bolt explains patiently. "Radios generally go up to 64 QAM. We can go up to 256 QAM (I cannot tell how yet because we have a patent pending). 256 QAM would give you 150 Mbps. We also use multibeam space time coding. We fire off multiple images at 256 QAM, some of payload A and some of payload B, so we have 2 loads of 256 QAM."

The Spectra is therefore very efficient. "We achieve 10 bits per second per Hertz. That's 300 to 400 percent better than the competition."

The company expanded the Ethernet interface from 10/100 to 10/100/1000 to accommodate the higher bandwidth offered by the Spectra. The company also added a 1000 Base-SX (see Ethernet Designations) fiber optic interface as well as dual T-1/E-1 interfaces.

The company also announced that its new radio is WiMAX compatible. "That doesn't mean compliant," Bolt says. "When you're managing a network, you're using SNMP, which uses MIB to define parameters, starting with whether the radio is on or off. There's a MIB for WiMAX, which is an option when you install the radio. You can use a private MIB, a public MIB, or the WiMAX MIB."

WiMAX channels are 10 MHz each, and Bolt expects the Spectra to be used in WiMAX deployments. "Because of our very high spectral efficiency, we can backhaul over 12 WiMAX channels, each 10 MHz wide, with our Spectra, which is 30 MHz. We can backhaul those 12 channels with our 3."

In the ISP industry, Bolt expects ISPs to use the Spectra near the core of the network. "Wireless ISPs are building a root and branch network, and the bandwidth demands are getting bigger and bigger, especially close to the core," he says. "In addition, there's limited spectrum available because much of it is used by point to multipoint radios." A combination of high bandwidth and efficiency will be perfect for the core, he believes.

One happy customer
Dustin Jurman, CEO of Tampa-based business WISP Rapid Systems agrees. He told us he was very excited by the bandwidth when he first tested the radios.

"When they say, 'we have 300 Mbps radios,' normally, I'd laugh and go on down the street, but these Orthogon guys, they produce," says Jurman. He tested the radios at ranges of less than one mile but not mounted on towers. He found average speeds of 260 Mbps.

That's how he expects to deploy them, at relatively short range but high bandwidth. "I need big fat freakin' backhauls," Jurman tells us. "If we see an alert, we can source bigger backhauls or add a channel, however you build your own sprinkler system. I don't want to look at bandwidth reports. I want to go home."

Asked if he'd want asymmetry in bandwidth allocation, Jurman demurs. "It's not like that anymore. People use the 'net for more than just surfing."

Jurman's business customers are exchanging data, and lots of it. "We're running at capacity at backhaul."

He adds that although many WISPs are built on a root and branch model, Rapid Systems is built on a ring model, and still it needs fatter backhaul pipes. "We've been collapsing backhauls. They simply cannot handle the bandwidth. I brought the Spectra radios out to test them (I tested them in Alpha/Beta). The throughput on these things! It was pushing the limits of the PCI bus. We got 7 GB in 5 minutes."

Jurman is dismissive of the 5.8 GHz competition. "Others claimed 72 Mbps or whatever and it wasn't true."

Jurman needs radios that can supply those backhauls. "I want them to fix my hard problems, not my easy problems."

Pricing and availability
Orthogon Systems' OS-Spectra radio is available today for $19,995 per link, including 2 radios. The system is available with or without antennas for the same price.

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