Engineers at the wireless networks in Minneapolis knew something terrible had happened even before the first news flashes. An unexpected spike in cellular phone traffic followed within minutes of the collapse of the Interstate 35 W bridge across the Mississippi River.
"They turned on the radio, heard the news and initiated a conference call at once," a T-Mobile spokesman told the Chicago Tribune. "They had extra radios installed at two cell towers nearest the bridges to double capacity within two hours of the collapse."
Despite the extra measures taken, many customers soon found that their cell phone calls could not get through. Worse, the Tribune reported, rescue workers, in their first test of a new universal radio system, turned to their personal cell phones as back-up.
Authorities pleaded with residents of the Twin Cities to stay off their cell phones, fearing clogged lines would hamper rescue efforts.
In an emergency as massive as the one in Minneapolis, the performance of cellular phones can become a matter of life and death. Yet, time and again, wireless providers slammed with sudden overwhelming call volumes have proven unable to provide anything beyond an automated voice endlessly repeating the same message - "Current network not available."
However, effective alternatives exist. Industrial emergency responders may find themselves eligible to participate in two federal programs designed to get high priority calls through the existing telephone system, said John F. Dinneen, outreach coordinator for the National Communications System (NCS - www.ncs.gov).
"These programs are part of the Government Emergency Telecommunications Service," Dinneen said. "'Government'is a very important word in that we created these services in support of national security and emergency preparedness. We've extended those services offerings to include state and local governments. Now it has become apparent that industry plays an important role in continuity of operations and government."
Specifically, the programs involved are the Wireless Priority Service (WPS) and Government Emergency Telecommunications Service (GETS), both maintained by the NCS.
WPS is a priority calling capability that greatly increases the probability of call completion when a National Security and Emergency Preparedness (NS/EP) user is otherwise unable to complete emergency calls with a cellular phone. GETS provides emergency access and priority processing in the local and long distance segments of the Public Switched Telephone Network (PSTN).
"The problem with a cell phone is if you can't get the first radio channel into the cellular network, you can't even begin making your GETS call," Dinneen said. "So WPS creates a GETS priority for a radio channel to get into the network."
WPS is an add-on feature subscribed on a per-call phone basis that works with existing cell phones in WPS enabled cellular networks. No special cell phones are required. WPS provides priority for emergency calls through a combination of special cellular network features and the same "High Probability of Completion" features used by GETS.
WPS addresses congestion in the local radio access channel (or cell), which is often the reason that cellular calls cannot be made during heavy calling periods or when damage to network infrastructure occurs. WPS automatically provides priority access to local radio channels, placing WPS calls in a queue for the next available channel if a channel is not immediately available.
WPS is available through AT&T, Cingular, Verizon, T-Mobile, Sprint/Nextel and Southern-LINC. It will shortly be available through Cellular South. Radio channel priority does require WPS feature activation on the calling cellular phone.
The service does not preempt calls in progress nor does it allow WPS users to monopolize all available cellular resources.
"If you are a WPS caller, you dial a special code on your cell phone and get the next available channel," Dinneen said. "Now the FCC says we can't give all the channels to priority use, so we have a swapping algorithm that gives every fourth channel available to an emergency responder. The other three must go to the general public."
A one-time WPS activation costs $10 per phone. Monthly WPS service is $4.50, plus 75 cents per minute usage fee. For more information about WPS, visit wps.ncs.gov.
Once the call reaches the tower, GETS takes over. GETS is a White House-directed emergency phone service program that supports federal, state, local and tribal government, industry, and non-governmental organization personnel in performing their NS/EP missions.
When the public telephone system "crashes," it actually remains fully functional, said Dinneen.
"Nothing is broken," he said. "It's just that the system is being asked to deliver six or eight times as much capacity as it has, which is not possible."
GETS is intended to be used in an emergency or crisis situation when the PSTN is congested and the probability of completing a call over normal or other alternate telecommunications means has significantly decreased. The service uses local networks and wireless providers, personal communications services (PCS), major long-distance networks such as AT&T and government leased networks such as the Federal Technology Service, the Diplomatic Telecommunications Service and the Defense Switched Network.
GETS operates as a cost-effective, easy-to-use emergency telephone service that is accessed through a simple dialing plan and a personal identification number (PIN) card verification. It is maintained in a constant state of readiness as a means to overcome network outages through methods such as enhanced routing and priority treatment.
"If you have a GETS card, you are able to invoke a priority inside the public telephone network over public calls," Dinneen said. "This does not mean preemption. It will never knock another call off, but it does give you a priority in two important ways."
GETS does not guarantee the caller that their call will automatically go through. If the telephone circuits the GETS caller is attempting to access are busy, the caller does not get a busy signal, Dinneen said. Instead, the call is placed in a queue and given priority when the next circuit becomes naturally available.
"If there are network management controls that are blocking traffic, we will give you a pass around those tools," Dinneen said. "Those are two pretty powerful capabilities to help an emergency responder get their call through."
Immediately following Hurricane Katrina, GETS calls made in the Gulf Coast region were made with a success rate in the mid 90 percentile, he said. Most routing failures were caused by damaged end offices, cell sites or un-available trunks.
WPS calls automatically become GETS calls when a signal to the tower is acquired, he said. GETS calls can be placed from either cell phones or land lines.
"We know that the cell phone is in the hands of a WPS authorized user, so we don't require the GETS pin code to be put in," Dinneen said.
To apply for a GETS card, visit gets.ncs.gov. White House criteria are used to determine if an applicant qualifies.
"There is an opportunity for the applicant to answer in 200 words or less 'What is your NS/EP mission?'" Dinneen said. "You get to state why you believe you should be able to use this service. Then they submit that statement online."
That GETS and WPS is a relatively new concept in industrial circles is being actively addressed by NCS, Dinneen said.
"The NCS now employs five people traveling to conferences trying to get the word out," Dinneen said. "Industrial people just didn't know about it. I have people come up to me all the time and say 'I didn't know this existed.'"??????????????????????????????????????????????
John F. Dinneen will be on hand at the 2008 Industrial Fire World Emergency Responder Conference & Exposition, April 28-May 2, in Beaumont, TX Visit him at Booth 511.