The interoperability quandary
A category 5 hurricane slams into the South Carolina coast, flooding coastal roadways, destroying houses and knocking down powerlines. A freight train carrying hazardous materials de-rails in Nebraska, forcing the evacuation of thousands of people and requiring the assistance of federal authorities to decontaminate and re-construct the accident scene.
It’s not a question of if the next large-scale crisis will occur but when. In such situations, it is the coordination of multiple first-response agencies that ensures successful management of the public’s safety.
However, many existing radio systems do not allow individual agencies to communicate with one another. As a result, legislators, federal agencies and organizations such as the Public Safety Wireless Network and the Association of Public-Safety Communications Officials have identified interoperability as a crucial public safety issue to address. Mike Byrne from the White House Office of Homeland Security was quoted as saying, “My idea of music from God is interoperability.”
The need for coordinated communications is clear, but the question remains: How do we achieve this end? To date, two schools of thought have been debated. The traditional suggestion has been to move all first-responder departments to a single radio-based system, requiring state and local governments to replace all radio equipment and infrastructure with new standards-based equipment. Due to the tremendous costs, time and frequency requirements involved, this approach is not feasible.
A more viable approach is to achieve large-scale interoperability via a network-based solution, using similar principles as communications networks used by Internet providers and voice carriers.
Such a network would connect existing systems into regional, statewide or national systems to create a private Intranet for multi-agency interoperability without requiring the purchase of new end-user equipment.
With significantly less infrastructure investment, easy compatibility with disparate systems, quick time to implementation and flexibility for future upgrades, this network approach offers the best option.
[Some agencies are opting to use “patches,” an effective, yet old-fashioned way of achieving interopability. See sidebars.]
Network-based interoperability works with Internet protocol-based technology or packet switching. Traditional voice networks (telephony or land mobile radio) are circuit-switched. In circuit switching, users share an exclusive connection (a circuit or radio channel) for the duration of the conversation. With circuit-switched technology, one call ties up the dedicated circuit.
In packet switching, information is divided into packets, discrete units of data with address labels that direct them to their final destinations (the end-user devices). Multiple users share access to a circuit or radio channel by taking turns placing their packets on the channel. Every end-user device on the network has an IP address, and calls are routed to their destinations — groups, individuals or data terminals — by a combination of network hardware and software.
The principal requirements of critical communications networks can be met with a private Intranet tailored for public safety use. The private Intranet can be designed to provide the fast response times, excess network capacity, talkgroup configuration, high-quality voice and security, and interoperability that are essential to public safety.
A major reason large-scale interoperability solutions do not already exist is cost. It would be expensive to purchase entirely new infrastructure and end-user equipment required for a radio-based system.
However, with an IP-based solution, it isn’t necessary to invest in new equipment because it is “technology neutral.” This concept is best understood in the context of today’s public Internet. Regardless of the type of end-user device — a PC, PalmPilot or iMac — each can connect to the Internet.
With IP-based interoperability, existing radios can access the network and communicate via IP. The flexibility of the network infrastructure allows communications to appear seamless to the end-users.
As a result, there is no need to dedicate resources to training first responders on new radios. Radio system upgrades can be made as departments desire or require over time and as budgets allow.
Even if it were possible to equip everyone with the same radio, build out new infrastructure and complete all necessary training, radio-based systems still possess drawbacks. Available radio frequencies for public safety are a scarce commodity, with just over 10 frequency bands existing today. Because it would be impossible to design a large-scale system where all new radios fit within the same frequency band, a true interoperability solution must have the ability to cross-band, allowing VHF radios to talk to 800-MHz radios. Because it’s network-based and not reliant on frequency availability, an IP-based solution accomplishes cross-banding among disparate radios.
Radio standards age quickly. The latest and greatest comes out every few years, rendering once “state of the art” equipment obsolete. Will upgrades be compatible with existing radios, or will every agency have to upgrade to remain interoperable (starting the whole process over again)?
With an IP-based solution, there is no fear of future technologies. Because an IP-based solution is technology-neutral, equipment developed in the foreseeable future will still be compatible with the network.
If local and state public safety departments can network first, they will have found a way to enhance their communications system and, most importantly, improve their ability to protect the public.
Herther is director of product integration at M/A-Com Wireless Systems.
Union, justice, confidence
by Nikki Chandler and Don Bishop
Louisiana’s state motto is well reflected in Chief Duane D. Johnson’s attitude toward interoperability and New Orleans’ preparation for homeland security.
The assistant superintendent and deputy chief (who is chief of operations) at the New Orleans Police Department said that “the ability to communicate is critical to response.” And public safety agencies in his state seem to be able to communicate.
New Orleans’ location presents special challenges to interoperability with its proximity to the Gulf, intracoastal canal and Mississippi River. “The challenge there is the Coast Guard and the water response units, and Harbor Police,” Johnson said.
Port security is crucial. “Potential targets, which include chemical plants and key waterways, have increased awareness of why public safety agencies need to communicate through radio,” Johnson said.
New Orleans already has established a level of interoperability with the state through “a patch on two frequencies. They have Motorola Astro and we have EDACS, and people have been told the two can’t operate,” Johnson said. “We established console patches with radios and then went hard patch with phone lines.”
Patches and mutual aid
by Nikki Chandler and Don Bishop
Ozaukee County handles interoperability through a single radio system, mutual aid channels, radio patches — and meetings.
“Interoperability has a broad definition,” said Duane Willborn, radio and telephone systems manager for the county in Wisconsin. “We have a users’ group within the county … we meet probably every three months. We talk high-speed chase policies, emergency operations as far as what happens with hazmat stuff. We discuss holding traffic to a minimum when there is a multi-agency emergency.”
The county also uses a M/A-Com EDACS system that it bought in 1991 for $4.5 million.
“When we moved to EDACS, it was huge political issue because of the money. We had two police departments with brand new conventional systems,” Willborn said. “With Sept. 11, they said ‘enough of this. Our equipment has aged. EDACS is here and proven; it’s time to move.’”
Willborn said that over time, those departments discontinued installing 800 MHz and didn’t have enough units to move over to EDACS. “They wanted the rest of the county to hear them, but most of us had removed our conventional equipment.”