Why Cell Phone Networks Crash During an Emergency

Maggie Koerth-Baker of BoingBoing interviews Brough Turner, a phone system expert, about why it’s hard to make cell phone calls during an emergency. Turner addresses the mechanics and limitations of cell phone networks and points out that, nostalgia notwithstanding, the pre-cell phone era faced its own technical problems:

Well, say you’d have an earthquake in California. This was for the old Bell system. The national long distance routing has a set of standard, predefined routes and it had network control centers in New Jersey and other places. Things would get overloaded and they would manually intervene by putting access restrictions on new calls coming into the area that was congested. In the 60s, 70s, and 80s they would let through one out of every five call attempts. They were doing that manually and just arbitrarily to reduce congestion.

(HT: The Big Picture)

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  1. Matt says:

    Everyone is trying to make a call, network gets overloaded

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  2. Nhi says:

    This was the most ridiculous article/response. Thank you for doing such an insightful interview.

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  3. optimus maximus says:

    I was expecting a little more in the name of an explanation.

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  4. Jordan says:

    Another easy way to think about it:

    The amount of traffic that goes through an individual cell tower is dependent on a ton of different things, including time of day/week/year, weather, events, etc. It simply isn’t economical (or, at extremes with limited spectrum, possible) to install a cell tower able to handle 100% guaranteed service, so instead these systems are designed with a maximum capacity enough to handle everything that comes at it roughly 99.9% (+/- a nine) of the time.

    Unfortunately, the .1% is almost always one of two things: large public gatherings (i.e. festivals, sporting events) and crises.

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  5. Seminymous Coward says:

    They clearly need to implement a mode that plays every non-911 call from a regular subscriber a message like: “For the duration of the crisis, non-emergency voice calls are blocked. If you have an emergency, dial 911. If not, please send a text. Text messages will be free from this area until 4 hours after this message is last played.” The message might need to be embedded in the phone’s firmware for technical reasons; that would slow a roll-out, but it shouldn’t prevent one.

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  6. Kalen says:

    Just click on the link at the bottom of the article (THE BIG PICTURE) and you can find the link to the full article @ boingboing

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  7. Larry Anglin says:

    This is a well-known problem that is being addressed by the FCC. In my local area, first responders are in the process of receiving phones that have priority use of the cell system. The short blurb below from FCC’s web site describes the various efforts.

    Priority services. Three key federal programs are available that allow for priority call queuing and the priority provisioning or restoration of key communications circuits (see Network Reliability and Interoperability Council Best Practice 7-7-1011). The programs are:

    TSP, or the Telecommunications Service Priority Program, provides organizations engaged in national security and emergency preparedness (NS/EP) functions with priority provisioning and restoration of telecommunications services that are vital to coordinating and responding to crises. Telecommunications service vendors prioritize service requests by identifying those services critical to NS/EP. A telecommunications service user with a TSP assignment is assured of receiving service by the service vendor before a non-TSP service user.

    GETS, or the Government Emergency Telecommunications Service Program, provides emergency access and priority processing in the local and long distance segments of the Public Switched Network (PSN). It is intended to be used in an emergency or crisis situation during which the probability of completing a call over normal or other alternate telecommunication means has significantly decreased.

    WPS, or the Wireless Priority Service Program, improves connection capabilities for a limited number of authorized national security and emergency preparedness (NS/EP) cell phone users. In the event of congestion in the wireless network, an emergency call using WPS will have priority queuing for the next available channel.

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  8. Speed says:

    “Why Cell Phone Networks Crash During an Emergency”

    The network didn’t “crash” anymore than the portapotties crash at a crowded public event. The network was overloaded and people had to wait in line to make a call.

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