Anti-terrorism pushes the bounds of radio interoperability

The secure communications vehicle from Harris RF Communications looks like a cross between an office cubicle and a mobile command center.
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“If you look at the current military radio market, multiband radios cover the public safety bands,” Stevenson says. “Although the waveform would essentially be a clear voice capability, it could be used to provide a quick means for the military to interact with first responders. Classically this type of radio is too expensive for first responders, but DOD and DHS may want to offer some parts with National Guard units.”

The prime candidate for this role is the still-under-development Joint Tactical Radio System (JTRS), an open system architecture family of high-capacity, multi-band, multi-mode, software-defined tactical radios covering an operating spectrum of 2 MHz to 2 GHz and capable of transmits voice, video and data.

Joint Tactical Radio

Software Defined Radio (SDR) defines waveform modulation/demodulation functions in software. An SDR generates transmitter waveforms as sampled digital signals, converted from digital to analog by a wideband digital-to-analog converter, then converted to RF. In contrast, SDR receivers use a wideband analog-to-digital converter to capture all channels of the software radio node.

In this way, JTRS can function as a “universal translator” for otherwise incompatible military communications systems. If anything, public safety represents an even wider range of communications equipment, from legacy analog systems to state-of-the-art digital components. Such systems require an adaptive “translator” for communication. This interpreter identifies incoming signals and handles them accordingly. This requires intensive digital signal processing (DSP) with software-configurable logic rather than hardware-based specialized logic.

The APCO 25 waveform is the federal interoperability standard for federal, state, and local law enforcement and emergency radios. “In the JTRS situation, the APCO 25 waveform can be injected to provide full interoperability with almost any radio that may have first aid,” Stevenson says. “So they could go to an APCO-based network and the military could come in with JTRS and have immediate interoperability. As the military continues to develop the JTRS system, this is one of their clear goals.”

However, there are serious problems on both sides of this equation. JTRS is still several years away from deployment, and despite their advantages, SDRs are still too expensive for most public safety agencies to consider as replacements for existing fixed-function radios. A possible solution would be to create an emergency services hub concept—one or more SDRs on the infrastructure side to communicate with legacy systems, with SDR phones included as budgets and prices allow.

“Moving from legacy to secure systems is a huge challenge. JTRS should solve that – except for responder-to-responder communications if they don’t already have interoperable radios – but it won’t be ready for a few years,” Stevenson says: “probably in 2006 when it goes into main production and even then most units will go to the military and likely be too expensive for first responders.

“Police and fire departments want an inexpensive commercial radio that can just be thrown away if it breaks; the military has vastly different requirements, so trying to make one radio fit all probably won’t work.”

He says other options in the short term include using radio repeaters to channel a military VHF radio to access civilian frequencies, or using a telephone interface between the radio and the public switched network so that the military radio can communicate with a civilian responder on a cell phone . Another direction is the expansion of the use of HF networks.

“The US government has recognized and FEMA has installed a number of HF systems to be able to handle civil emergencies that traditionally involve natural disasters. But with FEMA becoming part of Homeland Security, a national HF network that can provide both secure and secure communications and infrastructure attack survivability is now necessary,” Stevenson says. “Although first responders have not traditionally used HF, there is growing interest both at DHS to upgrade and at the state and even local levels.”

Given the nature and tactics of the enemy in the war on terror at home, the sophisticated communications infrastructure the US has developed has become particularly vulnerable.

“The problem is not only the interoperability of the devices, but also how to route messages through the available systems. In New York, for example, the communications infrastructure fell apart,” says Rockwell Collins’ Eickhoff. “The Internet may need to be incorporated into the system architecture when cellular or land mobile radios are not available.”

But the more diverse the systems, the more complex the security problem becomes.

“There are secure media available commercially, including cellular, and the military has communications media that are very difficult to intercept or jam. You’ll need this kind of equipment to ensure communications are secure, but network management is also necessary to make sure the right people have the right permissions to access those communications. So how to properly organize all these communications with appropriate security is another problem that needs to be solved,” Eickhoff adds.

“If the only equipment they have is an unprotected VHF radio, that’s going to be another problem to deal with – and if you go to a cellular network, you’re likely to have congestion.” This is a problem until people equip themselves with technology that can ensure the security and privacy of messages, which will remain as long as legacy equipment is available.”

That cities and facilities in the continental United States have become targets of foreign attack for the first time in nearly two centuries forces civilian public safety into foreign territory.

“There’s obviously an element of the unknown” that would be involved in responding to an attack with weapons of mass destruction, Phillips noted. “The traditional concerns of law enforcement and first responders would be in the area of ​​notification; in this case, post-9/11 needs heightened the needs for detection and deterrence as well.

“When you go from a localized incident to a wider area incident, based on the number and type of responding agencies, you have different levels of communication needs,” Phillips continues. “We’ve defined interoperability levels that emphasize the need for states to plan what their emergency capabilities are, the training needed and the communications solutions needed on a state and local basis. Going forward, each community should use the equipment they already have.”

However, local agencies tend to have specialized needs that have fostered the current state of incompatible legacy systems. Firefighters entering high-rise urban buildings have different frequency and technology requirements than police officers working in suburban and rural areas, or even firefighters in mountainous forest areas or the emergency medical services serving them all. And when an event on the scale of 9/11 occurs — or, worse, a weapons of mass destruction attack — it will almost certainly involve a multinational response, as was the case in New York, bringing even more exotic systems into the mix.

“One solution in a 9/11 scenario to provide the security you need and the ability to show up without knowing who you’ll need to interact with is TDC/ICAP (Theatre Deployable Communications/Integrated Communications Access Package), that acts like glue,” says General Dynamics’ Barney. “You can connect whatever communications you have and connect via satellite or landline or the Internet—it doesn’t matter.”

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