'Data-Centric' Army Wants Next-Generation Tactical Net.

A blend of advanced commercial and military wireless communications technologies is at the core of the U.S. Army's effort to give dispersed lower-echelon forces--which are constantly on the move--capabilities to send and receive massive amounts of data, video and voice messages at a faster clip and with greater reliability than is now possible.

Projects currently underway by Army and commercial organizations are pursuing more compact, agile and capable communications systems that will be required by combat units within the next 10 years.

Army researchers and industry suppliers believe that the performance of today's tactical communications systems could be improved significantly, given the advent of technologies such as digital multi-band radios and extended-range network capabilities. These experts also note, however, that communications networks at the brigade-and-below levels remain constrained by "legacy" radios--which are limited to a single waveform (a form of transmission) or to a single bandwidth, and have low data transmission speeds.

For several years, the Army has been working to "digitize" combat units. This essentially means that each vehicle in a division, for example, is part of a digital network, called the "tactical internet." Each vehicle has a computer terminal, so it can receive updates on friendly and enemy force locations, command and control, and fire support data, all of which are routed over the network.

Today's tactical internet is made up of several existing radio systems, each of which performs unique functions. The standard combat net radio is the single channel ground and airborne radio system (SINCGARS). The vehicle-mounted wideband radio used for data distribution is the enhanced position location reporting system (EPLRS). At the tactical operations center, commanders rely on the mobile subscriber equipment's tactical packet network, and the near-term data radio (NTDR).

Those disparate communications systems are connected via Internet routers that use the IP, or Internet protocol, the standard adopted by the commercial Internet and corporate intranets for transporting data packets.

In the tactical internet, vehicle-mounted computer terminals--equipped with the Force XXI battle command brigade-and-below software (FBCB2)--display a common picture of the battlefield.

Communication Needs

The future communication needs of forces on the move--the units at the brigade level and below--currently ate the focus of an Army project called Mosaic (multifunction al, on-the-move, secure, adaptive, integrated communications).

The current tactical internet cannot achieve the connectivity or high speed of transmission the Army wants for the future, so the next step is to build a "next-generation tactical internet," said David Keetley, director of space and terrestrial communications at the U.S. Army's Communications and Electronics Command (CECOM).

"The next-generation internet involves entirely new technology," said Keetley in an interview.

The backbone of the next-generation tactical internet will be a digital, programmable radio called JTRS, for joint tactical radio system. A JTRS, program office was set up to spearhead this effort. The plan is to field a family of radios, for use by all military services. Because JTRS will have an open systems architecture, each service or unit can program its radios for a specific function (handheld manpack, air-to-ground, air-to-air), to operate in a specific frequency band (very high frequency VHF, high frequency HF, ultra-high frequency UHF) and to receive and transmit dozens of different waveforms.

For the Army, two of those waveforms will be SINCGARS and EPRLS. The Army's large investment in these two legacy radios (about 250,000 SINCGARS and 8,000 EPRLS) means they will be around for many years, officials said. JTRS radios would be programmed to exchange data with SINCGARS and EPRLS.

For the next-generation tactical internet, however, the most compelling requirement would be a wideband network waveform, said Keetley, which would be needed to move large amounts of data, video and voice services, at high speeds. The Army has yet to decide whether it will use a commercial wideband waveform for JTRS, such as a satellite system, or develop a government-unique infrastructure.

"We need the wideband network capability so we can do video, as well as voice and data," asserted Keetley. "As we go to the new operational concepts of a dispersed force, the networking of all the pieces of the maneuver force for situational awareness, fire control, basic functions of war fighting are dispersed. The networking is essential." The huge volumes of data that the future force will manage cannot be handled by today's narrowband radios, he said, which are connected for distribution purposes but do not offer the data capacity forces will need.

The future wideband network waveform, said Keetley, would replace NTDR and EPRLS.

Under the Mosaic program, the goal is to have a prototype network by fiscal year 2003, said Gary Blohm, advanced technology demonstration manager at CECOM. The program, he explained, integrates wireless technologies and protocols in order to provide the infrastructure for the next-generation tactical internet.

Mosaic is about achieving "multi-tier communications," said Keetley. In the lowest tier, there are robotic sensors and dismounted soldiers. The next tier is the maneuver net, or the next-generation tactical internet. One of the drawbacks of the current tactical internet is it does not reach those soldiers or the unattended sensors. "It provides the interface to connect them but it doesn't include them," said Keetley. "It needs to include them." The next level after the maneuver net is the airborne network, which includes manned and unmanned air- craft and aerostats. The upper tier is the space layer, which has satellites.

"We need software, which we call 'dynamic multi-tier communications capability,' which allows particular transmissions to jump between those different layers in a controlled, efficient way," Keetley explained.

One of the elements needed to achieve this advanced connectivity will be advanced radios that can overcome the limitations of today's legacy radios.

JTRS will offer a "common operating system and common architecture" for all radio applications, said Ken Peterman, director of business development at Raytheon's advanced digital communications division, in Fort Wayne, Ind. The company currently is the prime contractor for JTRS integration work.

Michael DiJulio, Army program director for wireless and JRTS, predicted that the integration of JTRS with legacy systems "isn't t going to be easy.

To extend the range of the tactical internet, out to hundreds of miles, the Army Increasingly is favoring HF radios, said Keetley. VHF radios are used for line-of-sight communications. For distances longer than 20-25 miles, HF or UHF radios are needed. HF systems were thought to have been made obsolete by satcom technologies in the 1980s, but during the 1991 Persian Gulf War, the Army's satcom networks became so overloaded that HF emerged as an effective alternative, said Kevin Kane, director of business development at Harris RF Communications, in Rochester, N.Y. Even though HF radios had been unreliable in the past, he said, new systems have the so-called "automatic link establishment" feature, which improves connectivity.

The company demonstrated the integration of its AN/PRC-138 HF radio with FBCB2 Army platforms, said Jeffrey A. Kroon, senior engineer at Harris.

Networking VHF and HF systems is part of the company's strategy to extend the capabilities of existing radios for transmission of IP data, Kroon explained. The VHF radios have a much faster data rate than HF radios, but cannot reach beyond the line of sight. "What we are proving is that the Internet-based technology can work, even over HF, which is unheard of right now," Kroon said.

An IP-compatible HF radio could be used by a scout or by any user out of the range of SINCGARS of EPLRS, hundreds of miles away, and operate as if they were a member of the local network, said Keetley. "HF radio technology is being evaluated to see if the Army's tactical internet requirement should include that in the future."

The need to disseminate information over extended distances also is part of the Mosaic program. CECOM issued a so-called "broad area announcement," seeking industry suggestions for this project. Comments were due September 30. Keetley believes that there will be commercial technologies available for the Army to implement the next-generation tactical internet.

"But one area that we don't think commercial technology is addressing is the horizontal and vertical hand-off between different wireless networks," Keetley said. When a terrestrial radio user goes beyond a certain range, ideally that user should be able to connect to an airborne relay node, such as an unmanned aircraft, or to a satellite, in order to extend the range of a ground-based mobile network, he said.

Keetley would like to have protocols that can keep track of those data handoffs, and to expedite the data flow in "situations which you don't see in the commercial world."

According to Raytheon's Peterman, "The military will have the ability, with JTRS, to fold in commercial waveforms ... and to bring those into the security architecture, in ways that have been difficult in the past."

Guarantee Service

One sizeable technological hurdle for the Army's effort to field a next-generation tactical internet, however, will be finding a commercial solution that can guarantee uninterrupted service.

Today's Army tactical internet, unlike the commercial Internet, can guarantee service, said Peterman. "In the Army, there are certain types of traffic that require a guaranteed speed of service." A radar sensor seeing an incoming airborne threat has to get that information to a defensive weapon system in tenths of seconds, for example. "The commercial Internet doesn't guarantee service or speed," Peterman noted.

But Keetley is confident that commercial protocols will emerge. Some of those protocols, still in their infancy, allow users to send voice over IP, "meaning you can talk over the Internet," he said. "Commercial services have not been very reliable."

As the commercial demand surges for Web access through wireless phones and for voice-over-IP systems, there will be enhancements in quality-of-service protocols, said Keetley. "We will take full advantage of those and apply them differently to our problem. We are still waiting for standardization in the industry. ... We are experimenting with different providers and products.

The quality-of-service feature would allow an Army network, for example, to de- conflict urgent from routine messages, based on battlefield priorities.

A sizeable difference between the military and commercial worlds is that commercial networks essentially operate in an "unconstrained data environment," Keetley noted. "Things on the Internet were not designed with bandwidth management in mind."

The applications the Army runs over SINCGARS or EPLRS, meanwhile, are engineered to provide "maximum band- width efficiency." The SINCGARS data rate is 16 kilobits per second. Most home PC modems offer 33-56 kilobits per second. "We would do more if we had 56 kilobits but we get functionality with 14, because of bandwidth management," he said. "We have joint variable message formats, which take full advantage of the bandwidth available and use the least possible amount of data."

In the commercial sector, "they send you everything, even if you don't need it, such as banner ads. We would strip out all the non-relevant information."

Guaranteeing quality of service "is one of the hardest problems to solve," agreed Kroon, from Harris. The company worked on a proposal for the Army based on a combination of its line-of-sight channel access protocol, and a high-performance waveform (HPW). But, Kroon said, "We didn't get a good reading."

"Our channel access protocol for VHF is designed to provide that quality of service guarantee in the future, but that is only one piece" of what the Army needs, said Kroon. The HPW data transmission waveform, which can achieve 64 kilobits per second, was co-developed by Harris and the U.S. Army.

The channel access protocol in the company's VHF radios allows a user to pick up a receiver and talk in the middle of a data transmission, without destroying the data. "The data flow pauses while I talk and then resumes," Kroon explained. "Channel access was the single biggest problem for us in VHF networking [because] you need to share spectrum with so many other users."

But even though wideband waveforms and quality-of-service problems remain unresolved, advanced in radio technologies offer much promise for the Army's future tactical internet, experts said.

The newest radios on the market today are digital multi-mission, multi-band radios, which are software-based and are becoming increasingly compact, making it easier for soldiers to shift between waveforms and bandwidths without having to catty multiple radios. The Special Operations Command and the Marine Corps are making large investments in these radios.

The Special Operations Command awarded Raytheon a contract for up to nearly 1,000 multi-band, multi-mission radios (called PSC-5V). Deliveries are scheduled to begin in October, said Peterman.

Special operations forces also are buying the Harris AN/PRC 117-F multi-band manpack radio, Kane said. The command also ordered more than 4,000 AN/PRC 148 multiband intra/inter-team handheld radios, from Racal Communications, in Rockville, Md. That radio is sold to the Marine Corps and to elite Army light infantry units, said Felix Boccadoro, Racal's director of business development.

Another advantage of digital, software-based radios is their embedded IP interface, which eliminates the need for Internet controller cards, or external boxes that would have to be attached to the radio, said Boccadoro. SINCGARS and EPRLS, for example, require external Internet controllers to route data.

Boccadoro noted that a soldier could take a handheld computer, combine it with a network access card and a lightweight 2-pound radio, and have full connectivity with the tactical internet. The radio would have most of the capabilities of an 8-pound manpack radio, except satcom. It would mostly be suited for squad-level communications.

But digital programmable radios such as the 117E the 148 or the PSC-5V are not designed to be JTRS-type radios, Boccadoro said.

"They are software programmable radios, but JTRS is about sharing a common architecture and you would just use software for different waveforms," he said. "The current radios are not compliant with that architecture. They are a foundation or demonstration of the concept of JTRS--multi-band, multi-mode functionality."

When JTRS is implemented, Boccadoro said, radio companies will have to be able to build the hardware to host the software. "The industry will be like the PC industry. The waveforms are software you load into, that can be developed by anyone. So radio companies can do both hardware and software or one or the other."

Peterman offered an example of how JTRS would work: "If you have a three-channel JTRS radio, you could bring in a message over a Havequick net--a UHF waveform used for ground-to-air and air-to-air communications--and bring in to the JTRS radio. The message would then be rerouted over a second channel, that might go over a SINCGARS, or EPLRS net or a satcom net.

Recent purchases of multi-band, multi-mode radios by special operations forces have prompted criticism of the Army's strong reliance on single-waveform narrowband radios. Retired Army Lt. Col. David Fiedler, an engineer at CECOM, wrote in "Army Communicator," an in-house publication, that recent experiments "demonstrated the current generation of tactical radio equipment lack capacity and arent adaptive enough ... to support tactical internetting and data-transmission requirements." The Special Operations Command's multi-band radio technology, said Fiedler, "goes a long way in meeting current and future tactical radio communication requirements for an automated information-based tactical Army."

Peterman agreed that the ability to operate in various waveforms with one box makes the special ops radios more sophisticated that the standard Army combat net radio. "The vast majority of the products in the Army today do a single waveform. SINCGARS only does SINCGARS. EPRLS only does EPRLS," he said. "The products we are fielding today are multi-band and multi-waveform. The products we will field over the next two years or so will be JTRS, where those waveforms are implemented in software, primarily, which makes the radio lighter and able to do more functions.

As the Army prepares to field medium-weight "brigade combat teams"--as part of the service's plan to become more mobile--tactical communications capabilities must be taken into account, said Joe Onufer, Army program director for platform communications. The first two brigades, currently training in Fort Lewis, Wash., will have the current version of the tactical internet, with SINCGARS and EPRLS, said Onufer.

These brigade combat teams will be much less reliant on voice and more data-intensive, said Peterman. "They could use a radio architecture that is nor constrained by the SINCGARS radio that was designed for voice primarily. They could use a radio architecture that is more data-centric."

The Army, Peterman said, "eventually will have to buy a new radio for the brigade combat teams." These units, he added, could become the "first force" to implement the JTRS capabilities.