The problem with UK radio spectrum policy, apparently, is that we have too much competition and not enough proper disasters, which means our emergency services won't get enough radio spectrum until people start dying. That's according to Motorola's Jeppe Jepsen, who does have a vested interest as a supplier of kit to emergency …
Why can't the emergency services move to GSM and use the commercial networks? Would give them cheaper kit and probably better coverage.
Re: Why can't the emergency services move to GSM and use the commercial networks?
because radio nets work better in relaying information quickly to multiple endpoints. I'm told PTT over cellular is fairly well used in the States, but it never took off in the UK.
"move to GSM and use the commercial networks?"
have you read any of the writeups of how well the ordinary comms technology worked (or, if I remember rightly, didn't work) after the London 7/7 bombings?
That should give you any idea why sharing with commercial GSM may not be such a bright idea.
Anyone got pointers for further reading (or to refresh my memory)?
Actually any occasion where there is lots of GSM/PCN demand for little GSM/PCN capacity (motorway closure? wide area power failure?) might do instead of 7/7. It's not fun when it happens.
The aricle says "We suggested that said services <etc>". Who is "we" in this context? Bill? El Reg? Her Majesty?
@A.C. -- Re: "move to GSM and use the commercial networks?"
"have you read any of the writeups of how well the ordinary comms technology worked (or, if I remember rightly, didn't work) after the London 7/7 bombings?"
Right. In a word 'congestion'. Here's an old example that illustrates the problem. Some 40+ years ago there was no talk-back radio. When it became popular there were all sorts of quizzes, ring-ins and such where the radio announcer would offer a prize for the first to ring in. Telephone systems weren't designed to cope with thousands of people all lifting the receiver off the hook and they crashed.
It turned out that the old POTS telephone system of the time would likely go belly-up if more than 3% of subscribers tired to phone in simultaneously. Phone systems aren't designed for every subscriber to ring in simultaneously, in practice telephone engineers install plant based on the statistical average and this figure is, in fact very low.
The same principle applies with phone networks today, so during an emergency telephone circuits may be blocked. Dedicated wireless circuits won't suffer this blocking problem.
Re: "move to GSM and use the commercial networks?"
I remember the impact of 7/7 on both GSM and POTS services, even without the writeups, having experienced it first hand. Mobiles reported signal but actually trying to use it resulted in failure and occasionally, if you were lucky, a recording apologizing for line congestion. 9/11 in New York had similar results except that since most US mobiles at the time were AMPS devices many carriers lost signal entirely in the areas near the Trade Center due to the loss of trancievers, switches and power from the attack; POTS service was also affected to a lesser extent since the PSTN exchange under the towers kept working after the collapse of the buildings until they lost power.
A similar effect could be observed in Washington DC a two years ago during John Stewart's rally on the National Mall (so many people packed into the area that mobiles were fighting each other to reach the local towers).
During an emergency all public (civillian) accessible communications networks (wireline or wireless) will see sudden dramatically increased use. Military and emergency networks will as well but they have built in prioritization (the now retired US AUTOVON network used DTMF A, B, C, and D tones to set call priority to allow urgent commands to get through by kicking lower priority calls off the network).
There are similarities between the emergency services and, for instance, pop festivals. Both can need a huge local provision for a short period. The difference is that these large events are planned, and temporary base stations can be set up. But something like a train crash can happen in a remote spot, and need instant increases in service availability.
So if we are talking about a shared radio network to carry the traffic, it needs a bit extra capacity everywhere, and genuinely complete coverage. And some emergency service are still likely to need something better--how about Mountain Rescue?
The end result would be more complete coverage for us mortals, including in areas where it doesn't make financial sense to even have coverage. But somebody would still have to pay for it.
It's not so daft an idea, but it doesn't fit well with commercial networks.
Something I am not entirely certain of - but that I have been told by 2 different network operators - after complaining about odd signal issues. Apparently when the law came in about using mobile phones when driving - the network operators had to change the way the network works to help comply with the law. As such priority is given to a mobile phone that is travelling between cells while in a call. In our little village in the Scottish Borders - we can be in a call with 5 bars - but sometimes when a string of traffic comes through - the call drops - after much complaining to O2 and Vodafone about this issue - I was informed that this is the reason. Because our cells are small - if the cell is fully loaded and phones connect to it that are travelling - they are given priority over the phones which are stationary.
It seems to me that if the networks are clever enough to do that - it should be very easy to ensure that emergency services always get priority over normal users?
While I am on the subject of networks - something O2 told me which quite surprised me - did you know that the networks in the UK never actually came up with a agreement to allow you to make an emergency call on a network you don't belong to? So when you are out of signal and your phone says "Emergency Calls Only" - it's lying - you can't actually make an emergency call.
"during an emergency telephone circuits may be blocked. "
As I understand it the theory is that GSM/PCN architecture has a "Your call is important to us" priority bit somewhere which is supposed to enable emergency services etc priority access to the network during times of congestion (if necessary, the network drops calls which don't qualify as "important").
My recollection is that during 7/7 it didn't work at all, or didn't help.
Pointers to further analysis most welcome.
Walkie talkies on GSM
Nextels walkie talkie service was massively popular in the States but that's because it used an iDEN network. iDEN was effectively a two way radio technology which had duplex voice calling bolted on. Nextel is now being shutdown and the walkie talkie service moved to Push to Talk over Cellular running over a 3G network.
The problem with PTToC is the long delay (2 - 4 seconds) while the device transitions from idle state into active. It might not sound like much, but compared to Tetra which is just 300 ms to setup a call this is a long time to wait - especially when you need to pass an urgent message.
The other problem is capacity. Every PTT conversation requires a dedicated data channel. If you put 100 police offices in the same place then you need to maintain 100 active data channels on the cellular base station. This will quickly swamp capacity.
This is why PTToC hasn't taken off in the UK, especially for the emergency services. Orange tried it a few years ago and closed the service down. A UK startup called LionComms is trying to port a walkie talkie to run over 3G but I would expect them to have the same problems as PTToC.
LTE looks like it might solve some of these problems but not in it's current form.
Re: Walkie talkies on GSM
Good point anon about the number of channels tied up for multiple users.
There is another company out there who provide a cross network PTToC system.
This should offer greater capacity on a local basis.
Don't know if they're doing very well at the moment.
I work for one of their resellers and we've had very little interest in PTT.
I believe it's a preconception problem.
Those who have used "traditional" two way radio in the past "get it", otherwise your average joe doesn't see the advantages of "one to many" comms.
I am now 2p lighter!
The keyword is *emergency*
..like when there is an earthquake and all your cell towers fall down. The simplest, most self contained technology wins. We use simple VHF band radios for fireground communications. Sometimes even this simple tech fails (fire+smoke does have a bad effect!).
Fortunately when that happens I usually get one of the crew to run the messages over to the other side. Doesn't get much lower tech than that.
If we relied on GSM/3G/whatever then here in Australia we'd be screwed as soon as we moved away from a commercially feasible area. Which would be 90+% of the continent.
Donate some bandwidth. Don't be schmucks. Planning needs to be done for the *worst* possible disaster, not the most common when it comes to comms.
They like to place their "ex-employees" in gov't positions that have control over budgets, contracts, and vendor selection - they get hired due to their alleged crackerjack tech knowledge - and then they bring the business. Then they go rogue and forget who they're working for, hiring their friends, passing out Motopayola toys around the gov't hierarchy, privately trashing the emergency services they work for, forgetting they are supposed to pretend they don't work for Motopayola anymore while collecting a hefty gov't salary & benefits. The contract bidding was remarkable for its not being there...seriously.
Unless this is how it's done in the business - but I was shocked.
Being the "talent" - not in the IT arena - all one can do is sit back and marvel at the show.
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