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Cellular Phone Forum / General / GSM / March 2004GSM indentification tracking
Hey all, We are currently working on a project that involves tracking availiable mobile id's within a realtively small area (2.5 sq km). The idea behind this is that key personel often move on and off a site and it would be useful if it was possible to track who is availible at any particular time. Given that mobile phones broadcast their id's to the nearest transmitters is there any way using commodity equipment like gsm modems linux boxes etc we can monitor who broadcasts when? The is no requirement for any sophisticated data transfer other than the standard SMS alerts in the form of pages. Thanks for your time, Don Alexander GSM Development RooSoft Ltd I believe that it is unlikely that you can track cellphone users who enter an arbitrary area, since a GSM MS will only transmit when entering a new Location Area (which is likely to consist of several base stations (BTS), and a periodic location update is more involved than just listening to the broadcast channels. To me, it sounds like you need more interaction with the service provider. Another possibility is to make use of the networks location services and have some sort of mini-app on the phone that will update your server when in the location area. Good luck --Anthony > Hey all, > [quoted text clipped - 16 lines] > > RooSoft Ltd > I believe that it is unlikely that you can track cellphone users who enter > an arbitrary area, since a GSM MS will only transmit when entering a new [quoted text clipped - 10 lines] > Good luck > --Anthony Hmmmm don't spose there is an defined period for the location update is there? Another thought we had was to temporarily interupt service within the area just long enough for the phones to want to restablish contact with a BTS. Given that is would be somewhat undesireable at large to do this are there any guidelines similar to Wifi maps that give pescribed areas a overall coverage so we don't have all and sundry complaining about millisecond interuptions? We know of the damping technology availiable something along those lines I guess? perhaps located at the entrances to the area bit like a screening beacon. Any thoughts? Don Alexander GSM Development RooSoft Ltd >>Hey all, >> [quoted text clipped - 16 lines] >> >>RooSoft Ltd >We know of the damping technology availiable something along those lines >I guess? perhaps located at the entrances to the area bit like a >screening beacon. >Any thoughts? Well, my immediate thought is - what you are proposing (interrupting service) is illegal in the USA and most countries around the world that I have been in. -- John S. e-mail responses to - john at kiana dot net >>We know of the damping technology availiable something along those lines >>I guess? perhaps located at the entrances to the area bit like a [quoted text clipped - 8 lines] > John S. > e-mail responses to - john at kiana dot net Hmmm is it though? Given that the area is inside a structure it would be akin to 'checking in' and id badge on entry to the premises. I spose you can employ java tags for that sort of thing but that requires an awful lot of added complexity than is really necessary surely? What is proposed is a way of tracking mobile phones placement within a given area. As someone suggested it is possible to go to the operators but we theorise that their BTS network far out sizes the resolution that is required. So long as it is localised I am not sure there is an issue. Any more than using dampers in theatre buildings is? Question is how much accuracy can be judged with directional antenna and such? It is very hard to get actual real world data for these things when it comes to GSM. Wifi and the like are much more open though, but totally unusable. And would brief interruptions be enough to cause the phones to renew logon to a BTS anyways? Don Alexander GSM Development RooSoft Ltd > What is proposed is a way of tracking mobile phones placement > within a given area. As someone suggested it is possible to go > to the operators but we theorise that their BTS network far out > sizes the resolution that is required. What resolution are you looking for? John >>What is proposed is a way of tracking mobile phones placement >>within a given area. As someone suggested it is possible to go [quoted text clipped - 4 lines] > > John Well from the hazy specs I have been given it is an area of about 2.5 sq km, though the more I think about it the less important it is, if so long as a phone entering the area from whatever means , doorways, stairs lifts, etc. get's 'tripped' on entry. I spose that is possible with a very localised form or directional jamming. Litterally walk through a archway where you phone ceases to operate and logon again on the other side. The questions still remains can we then monitor the logon traffic to the BTS without actually being a BTS ourselves? And can we do that with commodity hardware rather than specialised telecoms kit? Any thoughts?  Signature== Don Alexander GSM Development RooSoft Ltd > Well from the hazy specs I have been given it is an area of about 2.5 sq > km, though the more I think about it the less important it is, if so > long as a phone entering the area from whatever means , doorways, stairs > lifts, etc. get's 'tripped' on entry. I spose that is possible with a > very localised form or directional jamming. Litterally walk through a > archway where you phone ceases to operate and logon again on the other side. Its been some time for me too, but IIRC a GSM MS in idle mode does not continously monitor the cell signals, instead it goes to "sleep" to save battery power and "wakes" up periodically to perform a RSSI and RXQL measurement of the cell site it is camped on and also the surrounding cells. Each time it wakes up it only performs one measurement on one cell site and will cycle through all cell sites on a list that the MS will maintain. Therefore, assuming it is legal to "jam" a channel within the GSM frequency band, I would seriously question whether a momentary loss of signal will cause the MS to perform a "hand-off" and re-camp on a different cell site. Even if it did, if the new cell site is in the same local area then it is doubtful if the MS will transmit anything until its next scheduled location upate even. So you will have to "jam" the signal "long enough" to have an effect on the MS, and even then you may have to arrange this at the boundry of a local area. > The questions still remains can we then monitor the logon traffic to the > BTS without actually being a BTS ourselves? And can we do that with > commodity hardware rather than specialised telecoms kit? Unless you have a BTS simulator I think you will find it extremely hard to "listen-in" and decode the transmission of a GSM MS. > Any thoughts? Just my two cents worth (but please note that I haven't worked in the GSM industry for over 3 years now so my GSM knowledge is at best dated and somewhat rusty!). > Well from the hazy specs I have been given it is an area of > about 2.5 sq km, though the more I think about it the less [quoted text clipped - 3 lines] > or directional jamming. Litterally walk through a archway where > you phone ceases to operate and logon again on the other side. I was thinking more of your using some form of location-based services provided by your carrier to track consenting phones (assuming they offer this). As others have said, most of the "solutions" you're canvassing are likely to be illegal in virtually any country. > The questions still remains can we then monitor the logon > traffic to the BTS without actually being a BTS ourselves? And > can we do that with commodity hardware rather than specialised > telecoms kit? As you've described the problem, another avenue is to consider the use of programmable phones that give you read-access to Network Measurement Results (NMR - the ranked neighbouring cell list). You just *might* be able to develop an NMR "profile" that can reliably test for "in-area / out-of-area", and transmit any transition to a central processor. There's no guarantee that this approach would be workable, but I'm at a loss to think of any other legal DIY solution that involves GSM without GPS. NMR can sometimes yield surprisingly good positional information (but often not). John >Hmmm is it though? Yes it is. It is illegal. <---- that's PERIOD Nothing more needs to be discussed about the legality. -- John S. e-mail responses to - john at kiana dot net >>Hmmm is it though? > [quoted text clipped - 5 lines] > John S. > e-mail responses to - john at kiana dot net Hmmmm, are you a lawyer or just an excitable indivdual? There are already technolgies that actively interupt GSM networks for use in prescribed public places. Perhaps you have never encountered one but that does not mean they do not exist or that the are 'illegal' in any sense of the word. In the simplest explantion I can, give mobile phone carriers have no 'rights' to broadcast in a private airspace it that is deemed unwanted. No matter how much they like to say talk anywhere. Please refer to this product for an example the technology. http://www.netline.co.il/LP.htm And if we can stick to the thread in general, how feasible would it be to use such technology as a means to prompt a Mobile GSM unit to rebroadcast it's id? In some senses it might even be a useful statistical tool if as people walked through a gateway it would be logged that that mobile phone was on the premises. I am guessing a dropped link of a second or two might be enough, but as I do not design mobile phones I have no idea what the resilience is to dropped comms. This is a new field we are experiencing and are trying to tie into our wireless lan development tools to give interoperabilty for them both. It is easy to track a laptop on a wirless lan or a pda but how many people are in a habit of wandering around with a laptop under there arm when going to and from a warehouse section maybe? > Hmmmm, are you a lawyer or just an excitable indivdual? There are > already technolgies that actively interupt GSM networks for use in [quoted text clipped - 7 lines] > > http://www.netline.co.il/LP.htm A law degree is probably unnecessary - to transmit in the licensed frequency bands (of which GSM is one such band), the equipment needs to approved (else the operator of the equipment will probably need a licence from the DTI if operating in the UK or from the FCC if operating in the USA). The "product spec" from the link above is abit thin, and although it proudly proclaimed that it is CE marked against EMC and safety, it does not seemed to carry any of the approvals (e.g. EN and FCC). Therefore I would personally not use such equipment with the possible except of using it in a completely shielded room that has been certified by an approved lab. > And if we can stick to the thread in general, how feasible would it be > to use such technology as a means to prompt a Mobile GSM unit to [quoted text clipped - 8 lines] > are in a habit of wandering around with a laptop under there arm when > going to and from a warehouse section maybe? Time to hire a GSM consultant prehaps? >>Hmmmm, are you a lawyer or just an excitable indivdual? There are >>already technolgies that actively interupt GSM networks for use in [quoted text clipped - 18 lines] > personally not use such equipment with the possible except of using it in a > completely shielded room that has been certified by an approved lab. Well granted it is a grey area in some instances but then again it depends on who you ask. As we know mobile phones have played a crucial and deadly role in both the Bali and the Madrid bombings and given this report http://www.cellular.co.za/news_2003/122003-gsm_jammer_device_security_devic.htm it may well be a case of revised rules for certain conditions. While I can see how Ofcom might get a little upset in todays climate there are plenty of valid reasons for jamming GSM networks in a localised area. Of course the other issues you talk about kinda make it seem less feasible to get an id code without first tracking it which add a whole se of complications to the issue. >> And if we can stick to the thread in general, how feasible would it be >>to use such technology as a means to prompt a Mobile GSM unit to [quoted text clipped - 10 lines] > > Time to hire a GSM consultant prehaps? hehe , why are you offering? :P Well I must admit I wished the cross over from Wifi to GSM was a little more transparent but I don't spose G3 and it ilk will be any easy to work with than exisiting systems , am I right? Thanks for your help anyways, we shall have to employ more lateral thinking I think. Cheers Signature== Don Alexander GSM Development RooSoft Ltd > > The "product spec" from the link above is abit thin, and although it proudly > > proclaimed that it is CE marked against EMC and safety, it does not seemed [quoted text clipped - 6 lines] > and deadly role in both the Bali and the Madrid bombings and given this > report http://www.cellular.co.za/news_2003/122003-gsm_jammer_device_security_devic.htm > it may well be a case of revised rules for certain conditions. While I > can see how Ofcom might get a little upset in todays climate there are > plenty of valid reasons for jamming GSM networks in a localised area. I am not sure, but I have always though that policing of the radio airwaves falls under a seperate government body (with the likes of Ofcom and previously Oftel being responsible for the service and commercial side). I am sure there are others who are more qualified than me to comment on this, but I have always assumed that it is a criminal offience to boardcast without the appropriate licence or permisson. Prehaps it is just the industry I have worked in where responsible employers provide RF shielded rooms to work in or else seek special licences from the Government to allow their engineers and friendly-users to trial their new developments. > > Time to hire a GSM consultant prehaps? > > hehe , why are you offering? :P Well I must admit I wished the cross > over from Wifi to GSM was a little more transparent but I don't spose G3 > and it ilk will be any easy to work with than exisiting systems , am I > right? I wish, having moved in to management (a step I have regretted ever since) I am as much use to you as a damp match. > Thanks for your help anyways, we shall have to employ more lateral > thinking I think. You may wish to look into developing location base application for the up and coming 3G phones (which at least in principle allows downloadable application to run on the phone). Surely you cannot be the only ones looking for such an application! Good luck. >Hmmmm, are you a lawyer or just an excitable indivdual? There are >already technolgies that actively interupt GSM networks for use in >prescribed public places. Not legally in the United States. I am a communication Engineer and specialize in Cellular of late. I deal with the FCC almost daily on the legalities of building, installing and comissioning cellular systems. Tell me where they are interrupting service and I will see to it that they are shut down and fined appropriatly. -- John S. e-mail responses to - john at kiana dot net > Hmmmm don't spose there is an defined period for the location > update is there? The location update period is up to the carrier. In my part of the world, it varies from 1 to 8 hours (different carriers), and from 1 to 3 hours (same carrier, different locations). John >>Hmmmm don't spose there is an defined period for the location >>update is there? [quoted text clipped - 4 lines] > > John Well that puts a damp squib on that idea then. I might have to explore more the other options of forcing a locations announcement. Cheers, Signature== Don Alexander GSM Development RooSoft Ltd Don, Even if you manage to interupt the MS-BTS link legally or otherwise, you still need to monitor the updateLocation messages. How do you propose to do this? I think your only hope is 1. Us the LBS service from the network provider which may or may not provide sufficient resolution 2. monitor the A-Interface signalling, using telesom hardware, which means getting the network operators permission. Keith |
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