After Years of Discussion and Debate, frequency-agile radios finally are arriving, with products scheduled to hit the commercial and public safety markets later this year. The adoption rate of these technologies will go a long way toward determining whether a much-promised new paradigm regarding spectrum access, equipment costs and, ultimately, intelligent radio becomes a reality.

Certainly the need for frequency-agile and multimode radios exists in the U.S. public safety sector. Thanks to regulatory policies and the realities of spectral propagation and fiscal budgets, public safety communications can be found throughout the band plan, with 700/800 MHz being the most popular spectrum for urban agencies and longer-range UHF and VHF bands serving as the spectral home to the vast majority of systems in less-populated regions.

While there are several network-based gateways — for example, the Raytheon JPS ACU-1000, M/A-COM's NetworkFirst and Motorola's Motobridge — that enable interoperability between disparate systems, they are limited by the fact that all parties have to be within the coverage area of their own system. When large-scale disasters occur, that option may not be available, said Tom Sorley, deputy director of radio communications services for the city of Houston.

“If I've got a 700/800 MHz radio and I'm out in VHF country, I don't care what kind of box you have — I'm not going to talk on their system,” Sorley said. “That's really the problem. Unless you have a ubiquitous network, even the system-of-systems approach that we all talk about won't work unless you're all on the same band or your radios are multiband.”


Two multiband products featured at the International Wireless Communications Expo in February were a VHF/UHF portable radio from Harris — already a hot commodity in the military sector — and the Liberty radio from Thales Communications that is a focal point in an interoperability initiative being spearheaded by the Department of Homeland Security.

DHS has awarded Thales with a $6.25 million contract to develop the Liberty radio, which enables communication in the 136-174, 360-400, 402-420, 450-512, 700 and 800 MHz frequency bands used by most public safety agencies for mission-critical voice communications.

“We have taken a user-centric approach to interoperability, where we try to put the technology into the subscriber unit,” said Steve Nichols, Thales' director of business development for DHS/public safety. “It's something we have had some success with on the military side. Special-operations command needed a handheld for the warfighter that could work on a lot of different infrastructures, because they never really knew when they [were] deployed what they would be faced with and what would be available, as far as systems and infrastructure to work on.”

Public safety responders encounter similar challenges, particularly during large-scale incidents such as natural disasters. In those scenarios, responders may have radios that are not compatible with the networks in the area. Even if they do have compatible gear, in some cases the disaster may have left the network unavailable, which was a problem in the aftermath of Hurricane Katrina.

With the Liberty radio, responders can switch to an authorized band and communicate instead of being tied to the band used in their home network, Nichols said.

“Now you can have a radio that can be deployed when you don't know what's going to be available to talk on and work on what's working, if you will,” he said. “In the past, you could have a VHF [Project 25] system and a UHF P25 system, and if you had a portable radio in one, you couldn't necessarily talk to a portable radio in the other.”


Not only can the Thales Liberty operate in multiple bands, it also can operate in three standardized modes: P25 trunked, P25 conventional and analog.

“What the Liberty does is provide you with the opportunity to get on the national interoperability channels on any band,” said Fred Frantz, chairman of the SDR Forum's public safety committee and director of law-enforcement communications for L-3 Communications Government Services.

Unfortunately, most of the largest public safety communications systems in the country use proprietary schemes, such as Motorola's SmartNet/SmartZone and M/A-COM's OpenSky platforms. As a result, the short-term interoperability potential of the Liberty radio is limited — as is its ability to be used as a subscriber device for entities transitioning from a proprietary system to a P25 system, said John Powell, senior consulting engineer for the National Public Safety Telecommunications Council.

Thales' Nichols acknowledged the benefit of having proprietary technologies in a multiband radio. “We think it would be a very nice thing to have in the radio; however, we don't really control the ability to do that,” he said.

Indeed, manufacturers such as Motorola and M/A-COM control their proprietary modulation schemes, meaning third-party vendors such as Thales would not be able to include those technologies in their radios without a licensing agreement with those companies.

“As beautiful as the Thales radio is … until we can get manufacturers to cross-license their proprietary protocols at a reasonable rate, then these radios aren't going to do what they were designed to do,” Powell said.

Some of those interviewed indicated that, because the hardware and software interfaces are not standardized, there may be technical difficulties involved with including proprietary technologies in a multiband radio environment. But all agreed that any technical snags pale in comparison to the economics associated with a manufacturer's decision to license its technology.

Proprietary technologies have been a component of public safety communications for years. Once an agency has chosen a vendor's proprietary technology, the agency often has little choice other than the vendor when it comes to buying equipment for the system, including replacement parts such as batteries. This formula can result in high margins for vendors, which helps to offset the risk associated with entering the relatively small public safety communications market.

Steve Frackelton, director of marketing for M/A-COM, said his company plans to announce its multiband road map later this year and is open to licensing its technology; in fact, it is discussing the prospect of licensing OpenSky to other vendors. Motorola declined to comment on licensing or on the rampant industry speculation that the company will unveil its own multiband radio this year.

Sorley said the prospect of key manufacturers in the public safety market licensing their technologies for use in frequency-agile radios made by third-party vendors is very unlikely. “I don't see that ever happening,” he said. “I wouldn't if I were them. What's their motivation?

“It's not like they're bad people; they're just trying to protect their market share,” Sorley added. “You can't blame them for that. I think sometimes [public safety] people get this idealistic thing in their mind and think, ‘Well, they don't love us.’ It's got nothing to do with that. They've got to protect their business.”

Dr. David Boyd, director of the DHS's Command, Control and Interoperability Division, expressed more optimism regarding the long-term prospects for licensing.

“Over time, the market forces those things to occur,” Boyd said. “I don't believe that it's going to be possible over the next decade for any of the major radio manufacturers to stick to proprietary systems. They will begin to marginalize themselves if they do that.”


If modulation schemes aren't a problem, a multiband radio could be a boon to public safety entities considering a technology upgrade. In Houston, most public safety personnel operate on a “very old” UHF system, Sorley said. The city has started the process of bidding a new system that will operate in the 700 MHz band.

“We didn't put this in our requirements, but wouldn't it be good to have a multiband radio that did 700/800 and UHF?” Sorley said. “Think about how much easier the … transition to the new [system] would be if you had that.”

Indeed, Sorley said one deployment problem he is facing is that he will have to complete the infrastructure buildout and go through the acceptance process before he can begin replacing subscriber radios. If a multiband radio that worked on the old and new systems existed, he could immediately begin replacing subscriber equipment at the agency's convenience — a significant issue with mobile units — and save several months in the total transition time to a new system.

While multiband technology offers value in such a scenario, some believe software-defined multiband radios also represent the first step in the evolution toward cognitive radio, which promises to bring intelligence to the radio that allows it to better take advantage of a given radio-frequency environment.

Whereas Thales' Liberty radio requires the user to turn a knob to switch between pre-programmed channels, a cognitive radio could make the switch automatically based on policies established for the device. Even so, the multiband nature of cognitive radios is just a piece of their potential value, Boyd said.

“What cognitive radio suggests it will be able to do is that the most important critical call — say an emergency broadcast that everybody's got to get right away — will automatically be able to get in and it will automatically silence the radios long enough for them to come in,” Boyd said. “If you take the right priorities and put them in place, it's much more efficient than having to keep pushing the button and getting a busy signal, hoping that eventually you can get through.”

Nichols said he believes that the Liberty radio is an ideal device to use for cognitive tests. In addition, he emphasized that Thales understands public safety's concerns regarding the integrity of its channels and is working to ensure that public safety spectrum is not compromised.

“We're building lots of software controls into it so that it will be used only the way the radios they have today are,” Nichols said. “The radios they have today — you can program, put it on a frequency and talk on it. That's really the only way you get there.”

Powell said he does not believe the frequency agility will be cognitive radio's most attractive feature to public safety, but he does believe the potential for such radios to establish self-configuring networks to support communications when networks are unavailable is something first responders will covet. Sal D'Itri, director of sales and marketing for cognitive-radio company Shared Spectrum, echoed this sentiment while emphasizing the need for engineering appropriate operational policies into the software.

“If I show up in a Katrina situation and we have 10 cognitive radios running our software, I want them to form a net as soon as they come up, I want them to adapt to frequency interference, and I don't want the user to have to figure out how that works — what band he should be on, how to switch bands or the fact that some guy who thought he was supposed to be in his band has now crossed over and is causing him a problem,” D'Itri said. “I want this group of people — they may be the first people into a disaster situation — to be able to communicate.

“And that's really what the cognitive aspect of that does, and the way we control that is through policy. And that's something you don't see in a multiband environment, this idea of policy control and a level of service,” he said.


As is often the case, a potential stumbling block to public safety's adoption of new technologies such as software-defined and cognitive radios is money, or more accurately the lack of it. While the Liberty radio has received plaudits from many in the industry, its projected price tag of $4000 to $6000 per unit may be difficult for some agencies to fund.

Even entities that have adequate financial resources may not be in a position to make a quick transition, no matter how enamored their officials are of the new technology, Sorley said. Few public safety entities can justify upgrading to software-defined or cognitive technology while their existing equipment is functioning properly.

“I think the [technology] life cycles are changing, but the funding cycle's not changing because it's so incredibly expensive to build a new system,” Sorley said. “Part of the reason IT networks can get refreshed so much faster is because it changed from the real proprietary stuff to the more open stuff, which drove the costs down. Then the life cycles could get faster, because it didn't cost as much.”

But there is reason for optimism in this area because frequency-agile, software-defined radios are not being developed in a public safety vacuum. With the largest U.S. commercial wireless carriers — AT&T Mobility, Sprint Nextel and Verizon Wireless — all boasting significant spectral holdings in the traditional 1.9-2.1 GHz band, as well in the 700-900 MHz range, the desire for frequency-agile devices using a single transceiver has never been greater.

With this in mind, companies such as BitWave Semiconductor and Terocelo have developed transceivers that can operate in a wide range of bands at costs expected to approach the price of current transceivers. Not only is this attractive to carriers, it is a boon to equipment manufacturers that typically have had to develop unique products for each band but could use one design for all bands with software-defined radio, said Erik Org, marketing manager for BitWave.

“The short-term value is our ability to address frequencies they don't cover today, and my ability to save costs, because my one part replaces three,” Org said. “The long-term value is future-proofing and simplifying supply chains as a result of [software-defined radios].”

Meanwhile, possibly the most exciting news could come from the Defense Advanced Research Projects Agency later this year. As part of the agency's cognitive-radio initiative, M/A-COM and Shared Spectrum are scheduled to develop a cognitive radio that would cost just $500 by the end of the year. For public safety representatives who have seen the price of military software-defined radios, the notion that a cognitive radio could provide more functionality at less cost is difficult to fathom.

“Let me put it this way: I'm not holding my breath,” Powell said. “But if anyone can do it, they have the right team in place.”

Shared Spectrum's D'Itri said cognitive radios can cost less because their intelligence allows more efficient use by operating on available spectrum with minimal interference factors. As a result, a cognitive radio does not need an RF front end that is as robust — and expensive — as that which existing radios currently need to communicate effectively, he said.

“You're able to reduce the cost of the front end,” D'Itri said. “And because the front end doesn't use as much power, you're able to have a smaller battery, so now the whole radio becomes smaller and cheaper.”

But the key to the adoption of this new generation of radios is clearly defining their functional benefits to the public safety market, said Rick Rotondo, vice president of marketing and communications for Spectrum Bridge, a startup company that will launch an online-based spectrum exchange later this year. Frequency-agile radios are ideal in the Spectrum Bridge vision — public safety entities could quickly share channels with neighboring peers on a temporary basis — but the descriptors “software-defined” and “cognitive” alone will not be big selling points.

“I don't think anybody's going to say, ‘I need a cognitive radio,’” Rotondo said. “What they do say is, ‘I need more capacity. I need more reliability. I need more bandwidth.’ And those are the kinds of things that cognitive [radio] can deliver. … [Users] don't care if you do it with a can and some string or a very sophisticated algorithm.”

With so many companies developing frequency-agile equipment, Frantz said he believes the incremental cost associated with adding bands to radios will decrease noticeably during the next several years. However, he does not believe public safety entities typically are in a position to wait to make a communications purchase until low-cost cognitive systems are on the market.

“My guess is that there will not be a significant hold-back based on the promise of cognitive radio,” Frantz said.

Sorley agreed, noting that the dilemma is an age-old problem in public safety, given the timelines inherent in radio-communication funding cycles for most agencies.

“To me, it's got to be based on the life cycle of your current stuff: ‘When do I have to get out of this [existing system] before owning the old becomes more risky than building the new?’” Sorley said. “So it isn't about the whiz-bang thing; it's more about the reliability and viability of the stuff you have now, knowing that it's going to take you awhile to implement the new stuff.”


Feb. 14

Harris announces portable radio for military that operates in the UHF and VHF bands.

Feb. 28

DHS announces contract with Thales Communications to develop a radio that operates across most public safety radio bands.

Fall 2008

Manufacturers scheduled to begin beta-testing low-cost, frequency-agile transceiver chips from BitWave Semiconductor and Terocelo in commercial handsets.

Dec. 31

Target deadline for M/A-COM and Spread Spectrum to develop a $500 cognitive radio for DARPA.


Commercial handsets with frequency-agile transceiver chips expected to hit the market.