Heavy call volumes on wireless networks frustrated end users and caused cell sites operating on backup generators and batteries to quickly falter during the massive power outage that crippled the northeastern United States late last week.
Given the situation, even the best system would have been unable to perform optimally, said Michael Grossi, a principle analyst with Adventis Group, who compared the massive blackout to a natural disaster.
Despite the fact that generators initially kept wireless facilities-including cell sites, base stations and call centers-working, heavy call volumes led the networks to reach capacity, which caused service to be blocked and calls to be dropped in the areas affected by the blackout.
And according to Grossi, over-capacity quickly drained the backup power being provided to cell sites. Wireless carriers are probably still struggling to determine which sites are down and which are running low on backup power, Grossi predicted, and visits to sites will likely be required to address the problem.
Multiple, redundant power sources like generators or batteries, neither of which would provide sustainable power over a long period, would be one possible solution to combat a massive loss of power on networks, but Grossi said such installations would be unlikely given the costs that would be required.
Verizon Wireless said its network remained fully operational, but conceded call volumes up to four times the normal amount blocked some call attempts. “Persistent callers were usually able to complete their calls,” the carrier said on Friday. The company also said there may have been isolated service outages due to backup power limitations at cell sites.
Sprint PCS and Nextel Communications Inc. said multiple sites were affected by the outage, and Nextel said it was diverting power generators from New York, where power was returning on Friday, to Detroit to combat the continuing outage there.
Canadian carrier Telus Mobility said its network was operational but service levels in Ontario were reduced, and service would be inconsistent. “People should be patient and use their phone’s signal strength indicators as a guide to whether or not service is available in their area,” said Wade Oosterman, executive vice president of sales and marketing at Telus. “Calls in progress may also experience interruption as, for example, people move from an area where power has been restored to one where power is still out.”
Meanwhile, wireless users were losing patience.
“I’m standing completely idle and cut off even though I have all the latest gadgets imaginable,” Eric Dawson, an Apple computer salesman, told Reuters. “I have a Bluetooth wireless connection in my cell phone. I can sync to my laptop to get Internet access. But I can’t even make a phone call. I can’t text message.”
Industry standards are in place to allow carriers to increase capacity and to give priority access to important end users, like emergency service personnel, according to Robert Sanchez, vice president of technology and chief technology officer at wireless consulting firm InCode Telecom.
Carriers can use vocoders, software embedded in cell phones, to decrease the sampling rates used to push voice over its network. Such a step would degrade voice quality of calls but would increase network capacity.
Priority access is also an option in which carriers can grant certain classes of service-be those emergency service workers or high-paying consumers-priority access to the network. In another scenario, carriers can geographically increase the power end users can put on the network to increase their chances of connecting. Increasing power, however, can lead to an increase in network interference, according to Sanchez.
Priority Access and Channel Assignment (PACA) is another priority access option under which phones equipped with PACA can connect to the network, but in doing so will bump someone else off. Sanchez said PACA can be put on any mobile phone, given the end user’s willingness to pay for the feature.
The New York Stock Exchange and the Nasdaq were fully operational and opened on schedule Friday. Wireless stocks were trading relatively flat.
