NIU challenges wireless networks

Jennifer Jenkins of Crystal Lake watched from her seventh-floor dorm room window as the horrific drama unfolded below with ambulances, police and others crowding the Northern Illinois University campus.

Someone told Jenkins about Cole Hall and she raced through her LG Chocolate phone's speed dial. It was 3:15 p.m. Thursday afternoon, just after a mass shooting left five students dead.

"I just kept going through my phone, one call after another, hoping to get through to someone and hoping they were OK," said Jenkins, a sophomore and finance major. "I tried at least 15 calls, and none went through."

She wasn't alone. Hundreds of mobile phone users on the DeKalb campus were flooding the wireless networks of all the service providers. The overload caused calls to be blocked from about 3 to 4:30 p.m. Some providers said service returned to normal between 5 and 9 that night.

Regardless of advancing technology and expanding high-speed networks, the wireless systems have only so much capacity for voice calls at a given time.

Verizon Wireless, AT&T and Sprint Nextel were among the service providers that had spikes in call volumes, ranging from 10 times to 15 times the normal level.

For large planned events, like the Super Bowl or Taste of Chicago, portable cell towers can be brought in to provide a turbo-boost for additional calls.

Verizon moved in portable cell equipment to NIU by 10:30 p.m. Thursday and likely will keep it there until Tuesday at no expense to the university, spokeswoman Carolyn Schamberger said.

"While call volume had already returned to normal levels, we went forward with dispatching the (cell) because we wanted to do everything we possibly could to provide assistance to the university and the community," Schamberger said.

U.S. Cellular Chief Operating Officer Jay Ellison said they saw 10 times the voice capacity and then witnessed a 25 percent increase in text messaging, a service that circumvents the voice network.

"That age group is very used to doing text messaging," Ellison said. "But we just couldn't build a bigger network or even expect that type of problem. After the Virginia Tech shooting, we brought in another cell site there, but we didn't at NIU because call volumes quickly returned to normal."

Sprint also had similar increases in voice and text messaging volumes, spokesman Dave DeVries said.

"Voice networks have a finite amount of bandwidth, and each cell site has a finite capacity to handle them," DeVries said. "When that capacity is reached, no additional calls are allowed through, and you get call blocking."

AT&T's cell sites have built-in technology that recognizes the increased call volume, and that allowed it to automatically reallocate capacity, an additional 30 percent in this case, spokeswoman Meghan Roskopf said.

"There's give and take here," said Roskopf. "When we see a sudden surge in call volumes and we increase our capacity, this comes at the expense of call quality, which absolutely makes sense in a case such as this. During the peak hours immediately after the shooting, call volume on our network was nearly double the normal rate."

A T-Mobile representative could not be reached for comment Friday.

While network capacity could be expanded further, it's not because of the cost. Also, the likelihood of using all that extra capacity is rare and not cost efficient, said Greg Brewster, associate dean of the School of Computer Science, Telecommunication & Information Systems at DePaul University in Chicago.

"The more you build out the network and provide more equipment, the more money it would cost them," Brewster said.

"You have to have enough capacity and cell towers to send a call back to the central office network, which is then switched out to its destination," Brewster said. "These networks are only designed for a certain number of calls, and when it's exceeded that capacity, they cannot instantaneously increase the capacity."

During the height of the wireless phone outage at NIU, Jennifer Jenkins was forced to do something she's never done -- use the landline in her dorm.

"My parents insisted on having it here," Jenkins said.

Still, she wasn't worried about her mobile phone service. "No one else's phone was working either, and we knew it would return at some point," Jenkins said.