Why It's So Hard To Make a Phone Call In Emergency Situations 179
antdude writes "BoingBoing reports on why it's 'so hard to make a phone call in emergency situations.' Quoting: '[The thing about] the radios is that they have different sizes of cells. You've got regular cells and then smaller sub-cells. You also have larger overlay macro-cells that are really big. They try to handle you within the small cell you're closest to. But it's a trade off between capacity — they'd like to have lots of small cells for that — and coverage — they don't want to put 100k small cells everywhere. So you might have a cell that covers a mile ara and then smaller cells within that that handle most of the traffic. ... In the end, it does come down to trade-offs. That's true of any network. You're interested in coverage first and then capacity. If you wanted to guarantee that a network never had an outage your capital investment would have to go up orders of magnitude beyond anything that is rational. So each network is trying to invest their budget in ways that make network appear to perform better. The cost of providing temporary extra capacity for the Boston Marathon, that's something that's in the budget and they plan for that event. But when you get something unexpected like a terrorist event, or an earthquake, or damage from a hurricane or tornado, then you have trade offs between capital and how robust your network is. Every time you have an event people say, "Oh, they didn't invest enough." But you look at New York City after Hurricane Sandy and Southern Manhattan was under 6 feet of water — all the buried infrastructure was lost.'"
Re:pay phones (Score:3, Informative)
The POTS (plain old telephone system, for the young whippersnappers) didn't have unlimited capacity to connect calls either. When many calls were in progress in an area, you could pick up the phone and hear the congestion tone right away. Conversely, if you tried to call an area where many calls were in progress, you'd hear the congestion tone before you'd finished dialing. Only with the internet has it become possible that everyone can talk to someone from a different area at the same time, and only if the ISP hasn't oversubscribed the network bandwidth too badly.
Re:sometimes (Score:3, Informative)
NCS/GETS (Score:4, Informative)
In fact, this very problem is why there is a US government program that lets certain emergency personnel/offices have priority over normal telephone traffic.
This is also why we don't normally see phone numbers in the 710 area code.
See: http://gets.ncs.gov/program_info.html [ncs.gov] for an overview.
(Wow, I feel like I'm back on comp.dcom.telecom)
Re:pay phones (Score:5, Informative)
Very much beside the point. Only a relatively small percentage of connected landlines can call out of area at the same time. If there is a reason for many people in an area to call or be called at the same time, POTS users experience congestion just like mobile phone users do.
Re:pay phones (Score:5, Informative)
The POTS (plain old telephone system, for the young whippersnappers) didn't have unlimited capacity to connect calls either. When many calls were in progress in an area, you could pick up the phone and hear the congestion tone right away.
That's in the days of computer phone switches. In the old days of mechanical relays, there were a fixed, limited number of dialtone generators (and first selectors -- the stepper that handled the first digit you dialed), so if local capacity was reached you just didn't get a dialtone right away.
You still hear this today, but usually after you dial. It's the fast busy signal. The fast busy means circuits are busy, try again. The slow busy means the destination line is busy. If you try a fast busy again right away, chances are good you'll get through, and you'll confuse the person who answers if you accuse them of being on the line when you called a minute ago.
Mother's Day was a big holiday for calling, so it was more likely to hear, or not hear, this happening then.
Re:uh, this is common sense (Score:4, Informative)
Not really, for planned events you bring in a few cell on wheels carts per carrier and increase the cell density, this is done all the time for football games and other sporting and political events. Now I'm not sure what the average use rates are for those events, but I bet for something like the superbowl it's well over 50% (for many of the folks at the Superbowl it's more about being seen at the game then it is about the game itself).