When Disaster Strikes

One of the hotter rumors at PCS '98 had nothing to do with wireless. It was that Hurricane Georges had shut down the Orlando, FL, airport. That prompted a lot of anxious wireless calls and put more of a strain on area networks, which already were saddled with thousands of wireless-happy attendees and storm refugees fleeing north along the Florida peninsula.

The state highway department threw open its tollbooths to accommodate the mass exodus, but it's never that easy for wireless carriers. Disasters suddenly can alter traffic patterns and spur usage that's double peak-hour levels. Case in point: As Georges approached the Mississippi coast, Cellular South saw usage increase by 15% to 20%. After it hit, usage was 50% above normal.

Fortunately, in the case of hurricanes and other disasters where people have a day or two of advance warning, usage often follows certain patterns. Before the storm, the highest usage typically is along highways and evacuation routes and in communities under mandatory evacuation. Weather forecasts also can help predict how usage might change before and after a storm.

"The level of evacuation depends upon the predicted severity of the storm," said Jana Ray, Cellular South advertising and marketing manager. "The Mississippi Gulf Coast has not had the threat of what is classified as a category 4 or 5 storm recently. Should this happen, we predict low call volume immediately following the storm (because) the area hopefully will be depleted of people."

Usage also can increase in neighboring areas not affected by the disaster.

"During mandatory evacuation, we may experience a slight decrease in call volume along the coast but are able to track increased usage in the northern parts of the state until the evacuation has been lifted," Ray said.

For residents and emergency personnel who ride out the storm, wireless often is the only means of communications left intact. When a January 1998 ice storm coated 65,000 square kilometers of Quebec, traffic increased by as much as 400% on sites serving residential areas, said Guy Raymond, Bell Mobility director of network operations for the eastern region. Disasters that hit without warning can take an even greater toll on network capacity because there isn't time to evacuate. Often, that translates into more injuries, more search-and-rescue operations and, as a result, more wireless traffic.

"The latest tornado disaster that we were hit with was in Beebee, AR," said Mike Stafford, Alltel director of network services for its central-market area. "That tornado took out all phone and electricity for the entire town. Usage increased in the area that took the biggest hit due to the relief efforts going on in the area."

That's because emergency personnel regularly use wireless to relieve the traffic loads on their 2-way radio networks.

"The public-service radio system is basically already running at capacity," said Mark Ripley, GTE Wireless assistant vice president, area networks. "The governments don't have the money to beef up those things. Any abnormality puts those systems into overload. What we've learned is that they can't rely on the public-service radio system during these types of situations. Therefore, they are very, very reliant on wireless."

ALL HANDSETS ON DECKIf there's a silver lining to storm clouds, it's that there is an opportunity for wireless to prove itself not only as a viable alternative to wireline but a much more robust alternative. Today, nearly eight months after Georges, Cellular South's minutes of use remain elevated, which Ray believes might be due to new confidence in wireless among both regular and emergency-only users.

Achieving that level of confidence isn't cheap or easy, however. Bell Mobility and PrimeCo deploy enough excess capacity to accommodate as much as six months of growth. That can be pressed into service to meet additional demand during a disaster. But others see assiduous network management as a more prudent approach for accommodating both gradual and unexpected demand.

"My goal is just-in-time capacity," said GTE's Ripley. "We watch our capacity every day. We move channels in and out as needed to provide the engineered grade of service. Having extra capacity sitting there is not providing any increased service to a customer and has a considerable price tag."

The alternative is to wait until after the disaster to deploy additional capacity where it's most needed -- if ice or downed trees haven't made travel hazardous or even impossible. One way to increase capacity without trekking to cell sites is Qualcomm's new SmartRate, which resides at the base-station controller. The application allows the voice-coding rate to be decreased incrementally to shoehorn more users onto a CDMA network.

"As the voice-coding rate drops, so does the power used in that transmission," said Phil Hester, Qualcomm director of worldwide CDMA infrastructure product marketing. "This allows the network to devote more capacity to other conversations if a call is in progress and the conversation is idle."

The trade-off is that voice quality diminishes, and that worries GTE's Ripley, who saw how crucial wireless was in the aftermath of the 1989 Loma Prieta earthquake.

"We're talking about an environment of high emotions and high tensions where voice clarity of every word could make the difference between life and death," Ripley said. "With everything else that a public-service person has to deal with during those types of situations, I don't think voice quality should be one of those concerns."

Another approach is Nortel Networks' Directed Retry, which increases the number of sites available to handle a call.

"Normally, when you are served by a site or sector, you can originate only on that site," said Raymond of Bell Mobility, which used the feature during the 1998 ice storm. "But (with) this feature, if a second-best server is available in the area, you could also be served by that sector."

Voice and control channels aren't the only parts of the network that can struggle when usage patterns are turned upside-down.

"It's not necessarily the wireless-access part that's going to have problems," said Qualcomm's Hester. "For example, if the switch is sized to some busy-hour call capacity, and the traffic goes up substantially, then the switch serving that area wouldn't be able to handle that additional traffic even if it were successfully delivered through the wireless-access part of the network."

Wireless also gets a hand from long-distance carriers, which can provide relief by adjusting the flow of traffic into a disaster area.

"When there is an unexpected (event), such as an earthquake, major fire or tornado, you see an immediate jump in usage," said GTE's Ripley. "A lot of that is I'm-okay-Are-you-okay?-type traffic. You have a lot of calls come into the area from the outside world. A lot of those calls are blocked in preference for calls going out (so) that people in the local area have a preference for getting out. AT&T and the other long-distance carriers have those kind of controls in place to help mitigate communications problems by adjusting the flow of traffic in favor of people trying to call out."