Network-centric radio project faces technical challenges

A cornerstone program in the military's effort to fight wars using tactical networks continues to face challenges, according to a recent report.

Although the military has successfully restructured the Joint Tactical Radio System, integrating waveforms being developed in tandem with the system remains a challenge, the Government Accountability Office found in a September report (GAO-06-955).

JTRS is designed to push high-bandwidth transmissions down to the warfighter and to help solve the interoperability problem that bedevils military communications. A waveform is a catchall term for the method of converting sounds into radio signals. This process includes modulating a carrier wave, message formatting, transmission protocol, and, especially for the military, cryptography.

Existing radio technology achieves that process through waveform-specific or proprietary hardware, making interoperability difficult to achieve. JTRS seeks to decouple waveform processing from hardware and make it a function of software, analogous to applications running on a desktop computer.

Future combat platforms, including armored vehicles, rotary aircraft, ships at sea and individual soldiers, are all meant to have JTRS radios. GAO estimated the total cost will be about $37 billion.

As part of its restructuring, the military earlier this year centralized management into a single joint program office and now favors an incremental approach to technology development. JTRS is organized into four domains: a ground domain for vehicles, soldiers, sensors and weapons systems; an airborne, maritime, fixed station domain; a network enterprise domain to develop waveforms; and a domain of special radios for special operations forces.

Ensuring interoperability among JTRS developmental waveforms, however, remains a challenge, according to GAO. Integrating them might require a gateway node located outside the radio for translating between waveforms, the report stated.

Some JTRS contractors said they've managed to integrate developmental waveforms without resorting to an external node, at least during a simulation. Boeing Co., which is competing with Lockheed Martin Corp. to win a development contract for the airborne, maritime, fixed station domain, said during a press call Friday that it has simulated an internal gateway between wideband networking waveform and tactical targeting network technology waveform. That may be adopted as a JTRS waveform, according to Boeing.

"We did it internally to surrogate radios, which aren't much harder than the actual radios," said Leo Conboy, Boeing's JTRS airborne, maritime, fixed station program manager.

The TTNT waveform has less latency than the WNW, he added -- although "should another signal in space and [wideband networking] be sufficient to the job, then we certainly [would be] getting that installed into prototype," Conboy said when asked if WNW could be sufficient by itself for the airborne, maritime, fixed station domain.

Lockheed Martin, which has also been doing simulations of airborne, maritime, fixed station domain JTRS technology, is not concentrating on TTNT as a solution. "It is proprietary…and requires very specialized hardware," said Glenn Kurowski, the company's airborne, maritime, fixed station domain JTRS program manager.

The JTRS program office likely will release a request for proposals for airborne, maritime, fixed station development in October, with a final contract award possible by March 2007.