Why Your Phone Doesn't Work During Disasters—And How To Fix It

When terrorists attack, mobile phone networks fail. They also go down during natural disasters, and even at big sporting events. Here's what causes network overload and what we can do about it.

When two IEDs went off at the Boston Marathon's finish line on Monday, mobile phone carriers were overloaded.

In the fog of disaster, hundreds of thousands of people worldwide tried calling their loved ones in the Boston area. The Boston metropolitan area's robust mobile networks simply clogged up as Verizon, AT&T, Sprint, T-Mobile, and other providers coped with a massive and unexpected surge. In the aftermath of natural disasters, terrorist attacks, and anomalous incidents worldwide, telecommunications networks simply can't cope with the sharp increase in call volume. Can that be fixed?

On Monday, mobile providers scrambled to cope with the unexpected call volume increase and to urge users not to make voice calls. For example, Verizon issued a terse statement saying they were "enhancing network voice capacity to enable additional calling in the Copley Square area of Boston. Customers are advised to use text or email to free up voice capacity for public safety officials at the scene."

In an email to Fast Company, Thomas Pica, Verizon's executive director of corporate communications, said that although Verizon "has a significant amount of margin in (their) system," significant events could exceed local capacity at individual cells. In addition, when sudden disasters such as the Boston attack do happen, engineers at mobile providers can monitor and adjust network elements in real time.

Users of every major mobile carrier reported outages in the Boston metropolitan area. This lead to the spreading of unconfirmed rumors which were taken as facts by the media, such as the Associated Press incorrectly reporting that mobile service had been shut off in Boston to prevent remote detonation of bombs with mobile phone times. A law enforcement official told the AP that a shutdown was taking place.

What did happen in Boston, however, was a routine swamping of mobile networks that takes place whenever an anomaly incident occurs. Shortly after hurricane Sandy, (now former) FCC chairman Julius Genachowski warned that mobile service was devastated by the storm. Although Sandy involved a physical destruction of mobile network infrastructure that was very different from the simple heightened call volume of Boston or the 2007 San Francisco earthquake, the basic elements are the same.

Mobile networks have bandwidth that is more than sufficient 99% of the time. However, when disaster strikes, the decentralized nature of the network means that whole geographic regions can be knocked out by increased call volume. Whenever the generous-but-finite bandwidth at carrier site buildings are strained, users are prevented from making voice calls. Because SMS text messages take up far less bandwidth, mobile carriers instead encourage users to text message each other. As Pica put it to Fast Company, "text requires less dedicated real-time capacity than voice. Data networks including LTE and EVDO were not impacted due to the nature of the way data systems are used."

During disasters, all of America's mobile carriers jump into action to mitigate service outages and, if needed, temporarily boost service. AT&T spokesperson Fletcher Cook told Fast Company that the carrier has more than 320 equipment trailers and support vehicles that can be deployed nationwide in case of disaster. As Cook put it, AT&T's goal during emergencies is to " route non-involved telecommunications traffic around an affected area, give the affected area communications access to the rest of the world, and to recover communications service to a normal condition as quickly as possible through restoration and repair."

It is possible to build redundancies into America's mobile phone infrastructure which would allow the easy placement of phone calls during crises. This would, however, be massively expensive and carriers would likely pass the cost onto customers. In a 2007 Computerworld article, reporter Todd R. Weiss discovered that adding regional redundancies to mobile phone networks is not economically feasible. However, mobile providers can temporarily boost coverage in areas where they anticipate trouble such as football games and music festivals. They can even take away mobile coverage—San Francisco public transit provider BART famously had carriers block wireless signals in order to prevent demonstrators from organizing after a homeless and mentally ill man was shot by BART police.

With that in mind, a series of new and innovative methods have been created to temporarily increase bandwidth during times of emergency. These range from mobile emergency wireless trucks to crowdsourced casualty clearing houses to creative bandwidth reallocation.

Two engineers at AT&T, Bob Mathews and Gary Chow, have devised a method of temporarily boosting mobile phone capacity at sporting events and concerts. AT&T's multi-beam antenna uses a special setup of narrow beams spaced 20 degrees apart, mounted at special events, to boost network traffic capacity up to 500% in order to deal with large crowds. The multi-beam antenna has already been tested at the San Diego Comic-Con, Coachella, and the Super Bowl. The pair helped develop the antenna in response to what they saw as a "telecom Moore's law," wherein data traffic consumption regularly doubled every two years.

Patrick Meier, a crisis early warning and humanitarian response expert at the Qatar Foundation, said that the Boston attack was indicative of a need for a new system which he calls a "Match.com for disaster response." Meier is currently working on a similar project at the Qatar Foundation to match local needs with publicly available information through a low-bandwidth database that combines crowdsourcing, microtasking, natural language processing, and machine learning to provide instant disaster relief information. In the case of Boston, a database accessible to anyone looking for information on a loved one or a runner stranded outside their hotel could quickly leave a message or find a place to stay.

Lastly, a quixotic attempt to boost Wi-Fi bandwidth could create a viable backup communications system during natural disasters or terrorist attacks. Globalstar, a relatively small satellite company, is attempting to convince the FCC to license their communications spectrum for Wi-Fi use. This can be done because Globalstar's allocated spectrum is right next to the spectrum bandwidth allocated for Wi-Fi use; if the FCC gave their approval, routers would be able to use Globalstar's spectrum through a simple software update. Globalstar has the option, if this project is approved, of jointly sharing the spectrum with multiple wireless providers or licensing it exclusively to one lucky carrier. By significantly increasing the bandwidth dedicated to Wi-Fi, users in public areas or crowded environments would enjoy much faster wireless Internet speeds on their mobile phones and tablets.

Additional reporting contributed by Ben Paynter.

[Image: Flickr user lragerich]

This story has been updated to include additional comment from AT&T.

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  • Ralph

    Cell phones don't work in these situations but walkie-talkies do work. The difference is that walkie-talkies are P2P; they communicate directly with each other, not through fixed infrastructure and centralized service provisioning. That's the real source of the cell phone outages. If cell phones were P2P, or better yet if we had architecture that utilized mobile devices like buckets in a bucket brigade, we'd have communications in any situation. (The instant response to this will be "It can't be done; there's not enough radio energy, you don't know what you're talking about, blah blah," but of course it can be done; it's just an entirely different paradigm than the one we've adopted.)

  • Geof

     The present model forces everyone to go through strictly licensed mobile companies and hand over their money like captives.  P2P would just be too liberating, somewhat akin to the World Wide Web before its present descent into the grip of the powerful few.

  • Geof

     Rather than just P2P, I should have said a phone system that can utilise both P2P and a network structure.

  • Erik Archer

    As Ben pointed out, data applications are frequently unaffected.  I've been in 2 situations where my normal voice signal was jammed up, but by simply turning on my VoIP application I was able to make calls. 

    Of course, if you use a VoIP app to try and call someone else's regular cell and THEY'RE ALSO in the affected area, then the call probably wont go through ("Unsleep" there's actually little to be concerned about regarding your comment) so these solutions are best for communicating with those who are further away.

  • Ben

    It's actually pretty simple if WIFI or LTE are working.  Use VOIP applications like GrooveIP that initiates GoogleVoice calls over the Internet.  I use the App when roaming International to save money.

  • Alex

    Hi !

    I'm former cellular network engineer, currently manager, in big telco company in Moscow. I can say that this article is very poorly writtet from technical point of view. Here is my short explanation about celllar networks:
    1) Cellular netwoks used allocated bandwidth based on their licencies. The main thing here is that they use "on-air" communication, i.e. bandwidth is COMMON to everybody in given area. So, "ministry of telecommunication" allocates parts of available bandwidht to cellular companies A. B. and C. in given area. Licencies and allocated frequencies for different companies are NOT equal, so company A. might have more frequencies in use than company B, so they have more voice capcacity. Since bandwidth is finite term, so EVERY cellular company has a FINITE cellular bandwidth, so it can NOT be increased EVEN THEORETICALLY !
    2) Based on above facts, we come to conclusion that voice capacity of cellular network can NOT be increased even theoretically!!!! The only thing they can play with is a voice codec, the better voice quality you get, the more bandwidth is used, the LESS voice capacity network has. So the ONLY way to increase network voice capacity is to use voice codecs that use less bandwidth, but it is obvious that those low-bandwidht codecs has a proportionally worse voice quality, the voice just sounds less natural, you can read about those codecs here: http://en.wikipedia.org/wiki/A...
    It means that in terms of disaster and network overload, engineers at cellular netwrok can change voice codecs of cellular trasnmitter to use low-quality, low-bandtwith codec like AMR 4.75k, AMR 5.9K, thus increasing capacity. But again, they VERY limited in increasing capcacity, the best increase they could achive is, roughly, 2 times voice capacity increase compared to "ordinaty" network operation. More network capacity increased is IMPOSSIBLE even THEORETICALLY !!!!!!!!!! So in terms of disaster when everybody is calling to their relatives, you will ALWAYS have cellular network overload. Forget about "multi-beam antenna" , it's a b**it. It could only work only if you have same special antenna at your mobile, but since you have same mobile so no network voice capcacity can be achieved this way.

    And yes, use sms, it use other than voice traffic channels and much less bandwidth than voice.

    Alex, shelupinin@gmail.com

  • unsleep

    great... now terrorists can solve the problem and keep bombing people, congratulations.

  • Me

    It's quite simple. Don't rely on technology. Have a family plan on where each family member should go in the event of a disaster. This is basic stuff in New Zealand where we constantly live under the threat of natural disasters.

  • lakawak

    That has nothing to do with this. The majority of people using the phoens were not people trying to find out where their friendsand family they they were WITH went after the bombs.  It was people who were there by themselves (Or even with people) who were trying to contact people WHO WERE NOT THERE to let them know that they were OK since their love ones knew they were at the Boston Marathon. So it wouldn't have helped if they had had some emergency plan of "If solmething happens, head to Boston Commons since the people they were calling may have been in California.

  • tostrivetoseek

    This article is incorrect. Phone service went down during the Boston bombings because it was deliberately shut down by officials who wanted to prevent explosion detonations by remote. AP reported on this. Get your facts straight.

  • tostrivetoseek

    Oops sorry; it was a bit too boring to read that far. Thanks for looking out.

  • Leeds_manc

    A bit too boring to read that far, yet you thought yourself qualified to criticise the author for not thoroughly checking facts. Perfect example of ignorance; learn from this, it's not the article's fault for being "too boring" it's YOUR fault. 

  • lakawak

    IT was like SIX paragraphs into the article. And that is too taxing for you to read? Are you an infant?

  • Gplace

    I find this article quite interesting in light of the fact that my Blackberry didn't let me down during
    hurricane Katrina.  I drove one of the first ERV's that was deployed just outside of Louisiana prior to the storm making landfall.  As I drove in my cell phone was one of the very, very, few that was still able
    - via AT&T to send text messages.  I was able to use the ligt as a flashlight in a completely darkened environment and I used the very same phone to help many people connect with their families when there was no other means available.  Yes, it was difficult to make a direct voice to voice call - but I promise you - because of the text messaging capability that I had with my Blackberry at the time - I am now
    a bonified Blackberry user until at some point some other electronic device comes along to convince me otherwise.  Georgia Moen Place - Dallas, Texas