Without power, but not powerless
From UHF to CDMA to GSM to Wi-whatever, the alphabet soup of the wireless industry offers numerous network options to meet virtually any communications need in nearly any situation. While they differ in protocol or frequency, each of these alternatives share a fundamental tenet: Without power, they are useless.
Although electrical power always has been an element of communications, most networks are built on the notion that the commercial power grid generally will be available. Even hardened land mobile radio systems with backup generators only are prepared to operate for several hours without commercial power.
For the most part, this has been enough. Not only has the commercial power grid been generally dependable, backup power plans usually are enough to keep systems running until the grid is available or until more generators — or additional fuel for the existing generators — can be secured.
This mindset was shaken forever in the aftermath of Hurricane Katrina, when even networks that survived the onslaught of the Category 4 storm were rendered useless by the failed power grid and the inability to refuel backup generators that couldn’t be accessed because of flooding (MRT, November, page 40). The incident has government officials and network designers scrambling for alternatives.
“The key was lessons learned from Katrina,” said Tom Frederick, Unisys Global Public Sector’s senior manager for interoperability solutions. “People were sending all kinds of things down there, but they all needed power or needed to be recharged, which also requires power. So, you had thousands of radios and communications devices down there just sitting around because they didn’t have any power.”
Perhaps the first strategic alternative that comes to mind in such situations is satellite communication, which does not rely on terrestrial power, assuming the handsets are powered. While certainly useful for some officials, satellite phones are not ideal for first responders who are too busy with their mission-critical tasks to be bothered with positioning their radio antenna in a manner that will establish a reliable connection with a satellite thousands of miles away.
Rather than of distributing typically scarce satellite phones to first responders, knowing the connection limitations, communications officials would prefer a solution that lets first responders use the radios they already have.
With this in mind, Arizona-based Space Data has developed a SkySite Network system that utilizes latex weather balloons to fly a 10-cubic-inch base station of less than 12 pounds in near space — between 65,000 and 100,000 feet above the earth — to provide coverage in a range measuring 100 to 500 miles in diameter.
“We’re close enough to the user that, instead of using your signal power to penetrate 10 miles of buildings, you’re using it to [transmit] to this balloon that’s a couple hundred miles away, so you can use a standard handset,” said Jerry Knoblach, Space Data co-founder, Chairman and CEO. “And, unlike a satellite, we’re not moving around at 17,000 miles per hour, so there’s no big Doppler shifts that you have to account for.”
Space Data provides two-way data communication in the 900 MHz specialized mobile radio band throughout Texas, Oklahoma and Louisiana, providing coverage in areas where paging networks aren’t built. To achieve this coverage, a weather balloon with a base station (see diagram) is released into the air, and naturally moves in an easterly direction. The balloon remains aloft for about a day, after which it falls to the ground several hundred miles from its release point and can be reused after recovery.
This system would be ideal to deploy when a network goes down, and it could be launched in advance of the landfall of a hurricane that it tracked for days, Knoblach said.
“Often times, you can deploy it a couple of hundred miles away from where some affected action is … so you don’t actually get the people who operate the system in harm’s way,” he said.
Space Data currently is testing its system with the United States Air Force, gaining experience with complex military protocols that should make it much easier to adapt the solution for commercial wireless or public-safety purposes in the future, Knoblach said. In addition to providing network availability, Space Data’s solution also can enable interoperability, he said.
“The system that we’re building for the military has the ability to fit up to three different channel cards in it. So, you could fly a radio up at 700 MHz and map that to VHF,” Knoblach said. “If you show up at some kind of natural-disaster emergency, and you’ve got to have people at the oil refinery … at 900 MHz talking to the public-safety people at 800 MHz, you could fly a balloon that maps those two together.
“For early parts of the recovery effort, that would be a real great thing. As the recovery effort moves along and people bring in cellular-on-wheels towers, and the infrastructure gets more established, the ground-based stuff will have more capacity than we will.”
The Space Data and satellite systems certainly are legitimate complementary communications technologies, but using existing terrestrial networks remains the optimum choice for first responders. However, Hurricane Katrina showed officials that even the best plans could go awry — M/A-COM’s key backup generator in New Orleans was located high enough to avoid flood waters, but wind debris punctured the unit’s radiator and left the network without power.
In an effort to ensure that its surveillance-video cameras can be located anywhere and are available all the time, West Virginia-based Elevated Security has developed communications towers powered by a combination of solar panels, wind turbines and hydrogen fuel cells.
“We found that we couldn’t do surveillance out at the perimeter of airports without spending an awful lot of money digging trenches,” said Mike Lee, president and CEO of Elevated Security. “I did some testing with just solar, but it wasn’t reliable enough because the sun was gone so much. So I combined solar, wind and fuel cell, and we came up with a package that absolutely works.”
Lee acknowledged that he has met resistance from some government and business officials in the past, who have dismissed his solution as part of the environmentalist movement. Lee said that’s not the driving force behind Elevated Security.
“I’m just a guy who was trying to solve a problem, and this was the best way I found,” Lee said.
With the passage of the Energy Bill, which provides tax credits for using alternative energy systems, solutions like those offered by Elevated Security have gained a measure of acceptance, Lee said. But it was the power-related problems in the wake of Hurricane Katrina that has been a “turning point” for the company, he said.
“It hasn’t taken off like a rocket, but the interest level has gone off the charts,” Lee said. “It’s getting exciting … a lot of people are realizing that you have to have an alternative power strategy.”
Elevated Security is working with Unisys on its interoperability solution that uses a media server as an IP gateway that lets a variety of devices — from UHF radios to cell phones to computers — communicate with each other. To fuel the Unisys solution, Lee said Elevated Security packages a 1 kW hydrogen fuel cell, a 1 kW solar panel and a 1 kW wind generator in a 19-inch rack on a mobile trailer.
Utilization of renewable energy has become more practical as the technology for these solutions improves and the cost of traditional energy sources continues to rise, said Scott Sklar, president of The Stella Group. Solar power not only is used in power calculators and watches, but it also is used with some digital cameras and cell phones, as well as LED traffic signs and satellites.
Sklar said he believes the next decade will result in a “transformation” as the renewable-energy industry continues to improve and devices are optimized to use less energy.
“As we move to more efficient digital technologies, your footprint goes way down,” Sklar said.
Lee agreed, noting that the emergence of solutions like xG Technology’s low-power Flash Signaling modulation scheme means future communications may not need to rely on the power grid — not only for mission-critical entities but for the general public, as well.
“I see a time when alternative power will drive all the [communications devices] in your house,” Lee said.
