Mobility

The NTIA wants cell phone jamming solutions

The National Telecommunications and Information Administration wants a way to block unauthorized cell phone use in prisons and is asking for our help.

The National Telecommunications and Information Administration wants a way to block unauthorized cell phone use in prisons, and is asking for our help.


The NTIA has issued a call for comments on plans to find a technical solution for the problem of contraband cell phone use in prisons:

NTIA is seeking comment on technical approaches to preventing contraband cell phone use in prisons. NTIA will develop, in coordination with the Federal Communications Commission, the Federal Bureau of Prisons, and the National Institute of Justice, a plan to investigate and evaluate how wireless jamming, detection, and other technologies might be utilized for law enforcement and corrections applications in Federal and State prison facilities. To assist in its evaluation of these technologies, NTIA requests information from the public on technologies that would significantly reduce or eliminate contraband cell phone use without negatively affecting commercial wireless and public safety services (including 911 calls and other government radio services) in areas surrounding prisons. Comments are requested on or before June 11, 2010.

The complete notice of inquiry is available as a 73-kilobyte PDF download.

As described in the NTIA press release about the call for comments:

"The illicit use of cell phones by prisoners is a danger to public safety and must be addressed," Assistant Secretary for Communications and Information and NTIA Administrator Lawrence E. Strickling said. "At the same time, we need to make sure that any technical solutions do not interfere with 911 calls, government or other legitimate cell phone use."

The press release goes on to describe desired solutions as consisting of means to wirelessly jam cell phone signals and detect cell phone signals, as well as "other technologies [that] might be used in federal and state prison facilities to address the issue of contraband cell phone use by inmates." The due date for any public comments is 11 June 2010.

As things currently stand, however, the FCC forbids cell phone jamming within the United States -- a measure that actually applies as much to the Department of Corrections as to private citizens like you and me. To address this, the Senate has already voted to approve a bill that would amend the Communications Act of 1934 specifically to allow cell phone jamming in prisons, and the very similar Safe Prisons Communications Act of 2009 is currently making its way through the House of Representatives.

Of course, wireless industry corporations would rather not let this bill pass the House and get signed into law. The CTIA (formerly the "Cellular Telephone Industries Association", now "CTI - The Wireless Association") appears to have influenced the FCC to prohibit testing of prison cell phone jamming equipment that the FCC had previously approved.

The problem, according to the CTIA, is that testing is likely to have a significant impact on cell phone service even outside the prison facility, including the ability to make 911 calls in case of an emergency. Jamming in a number of other countries worldwide, as well as in cases where regulations on jamming equipment were unknowingly violated within the United States, tend to show substantial impact on service outside the intended jamming area. One such case involved a Spokane, Washington school's attempt to control student cell phone use:

The idea was to prevent students from being able to use their cell phones during class for text or voice. However, when the jammer was turned on, it also jammed the radio that the Spokane County Sheriff had installed in the school that is used for both normal police activity and for swat teams that might be needed. The sheriff's quote went like this. "While I understand the problems / issues of teenagers and cell phones, interference to emergency communications is not acceptable. As I was not aware of this situation, I will be checking with the FCC enforcement bureau next week for any updates or information."

Short of building a huge Faraday cage around the prison to prevent the jamming signal from escaping the premises, solving the problem seems to be a difficult task at best. My Faraday cage wallet works well, but it is only a few inches long and wide, and less than an inch thick; hundreds of yards of prison property would be much more difficult, expensive, and impractical to try to enclose in a Faraday cage. Of course, a Faraday cage would also block cell phone signals, which would neatly solve the problem -- aside from the impracticality of building a Faraday cage around a prison.

Do you have any thoughts about a solution to this problem?

About

Chad Perrin is an IT consultant, developer, and freelance professional writer. He holds both Microsoft and CompTIA certifications and is a graduate of two IT industry trade schools.

174 comments
kjohnson
kjohnson

What's the worst that could happen if phones were allowed in prisons? At the moment inmates can use landlines but they need Prison Service phone cards which cost a lot more per minute than the phone cards you get at the post office. Whether or not a prisoner re offends after release depends heavily on how good his contact with his family has been. In any case all calls are logged, so that inmates who make calls with criminal intent are supplying the prison authorities with data, including position data, about their confederates.

rockysubu
rockysubu

Well, I am not very knowledgeable on this subject,i.e., cellular communications or Phased array Ae etc.I think a comprehensive solution encompassing prevention,detection and nuetralisation is required.So here goes:- A. Jamming. To be achieved by using directional antennas' placed along the perimeter of the prison(on the wall/fencing etc)>Means to ensure their physical security obviously need to be taken.The antennas'should be low power with minimal side & backlobes etc to prevent spillover beyond the prison limits as desired.A signal strength mapping exercise can ensure overlap of lobes to decide the numbers and location of Ae to minimise deadzones etc,while maintaining efficacy.The jammer Tx and perimeter Ae design can ensure sharp cutoff freq and minimal harmonics. B.The above to be supplemented by a Whitelist of cellular numbers of prison staff to be permitted by the service providers whose towers cover the prison perimeters.Any active phone other than the whitelisted ones will generate an alert to the service provider to be routed to a local watchdog and its antecedents verified and further acted upon as deemed necesssary. C. Emergency wireless communication for the prison staff. This to be engineered on a frequency totally different from the cellular phone freq and to have a powerful Tx and Rx Ae sufficiently high above the jammer Ae on the prison perimeter. The above of course does not cater for contingencies like a compromised prison staff lending a Whitelisted phone etc.details will have to be worked out with regard to the different freq bands used by service providers in the area(850 Mhz,900,950,1800 etc) Also, it will prevent prison staff from using their cell phones while on premises.So they need to be provided with adequately redundant landline comm and wireless comm as suggested ante. Request comments

tomkinsr
tomkinsr

Have the cellphone companies install cell phone towers in the prisons. All cell phones will connect to those units and the call gets intercepted. After all, you can't tell a cell phone to use a cell outside the one it is in.

johntec
johntec

Install a cell repeater system, pump in a signal "white noise" and broadcast it.The continous signal will overcome any chance of cell phone usage.

magic8ball
magic8ball

Is if prison personnel (guards and prison staff) have to make a call and cant whatever reason then thats a huge problem. Ex: land lines are down and a riot is in progress. Edited for clarity...

chriscollingwood
chriscollingwood

Rather than jamming at random, how about erecting trancievers for all banned technologies in each facility. The strongest signal will always be used, messing with the handset to force it to use a weaker signal is not trivial and monitoring can be implemented without too many issues (Think intelligence gathering). Any base station outside the facility will not be interfered with (as the internal BS would be part of the service) and normal use goes on unhindered. Of course the privacy activist might not like it too much, but why do prisoners get better rights than free citizens? Staff inside the facility would have register their equipment to prevent monitoring (but then why are they carrying in a secure facility in the first place? They are then a potential source of contrband devices) Fortunately, I live in Africa, where we have to register each and every device with a government agency before it is permitted on the network. Makes tracking very simple (or so they claim)

v941726
v941726

indian reservations and some national preserves are blacked out...cell towers are positioned carefully for this. not the best option for a total blackout since microwaves can stray

MSST8DOG
MSST8DOG

doesn't the military anti-terrorist units have a portable tower and technology that "hi-jacks" all cell phone calls and routes them to a control console so all calls can be intercepted and the terrorists can't coordinate with their partners?

jmgarvin
jmgarvin

Just setup a tower in or near the jail, bump up the volume to 11 and use it as a proxy to pass messages from "approved" phones.

Raymond Sirois
Raymond Sirois

Seems to me that placing a cell-phone tower AT the prison and thereby taking advantage of the capture effect would allow one to utilize MAC address security to control which phones were able to call out and which ones weren't. Unauthorized phones that got too close that tower would essentially be entering a dead zone until they moved out of range and were captured by another phone tower.

SysAdminII
SysAdminII

Put them on a chain-gang so they dont have time to lift weights and talk. Problem solved.

mcbinder
mcbinder

One big problem is that is not a FELONY to provide to a prisoner or use a cell phone as a prisoner in a prison. If you start tacking on 5-10 years for use by a prisoner and throw the corrupt guards in with the rest of the gang for a few hard, that would slow it down, in my opinion. mcb

BrightLibra@Gmail.com
BrightLibra@Gmail.com

The end result needs to be that anyone can use the network section that serves the prison except the prisoners with the same equipment? That must be what is needed, and the jamming is meant to only work with contraband phones, because passers-by have to have connectivity? That ain't gonna work. Remember, this is "Cellular" technology so make it so there are no cells that can be accessed from prison without authorization and you have it. That would mean a re-design of the surrounding sites, but would be the way to handle it.

jdriggers
jdriggers

How about detecting the phone ID, they all have one, so I believe. Have the provider turn off the service or lose their priviledge to use the towers in the area. This should solve the problem and make it expensive for the inmate to keep buying new phones that will be turned off the first time they use it. It might even help them realize they lost their right to have outside toys when they did the crime. Might want to take WiFi out also, with todays new phones having the ability to do internet calls. Not the expert here, haven't been on the inside of a prison or a cell phone in ages.

Steve__Jobs
Steve__Jobs

Yet another bleeding heart solution :) We need to control & restrict prisoner communication to the outside world. (1) That is what punishment is about...denial of so called common luxuries though that seems to be less relevant these days. (2) most importantly we cannot allow criminals to continue to administer/coordinate their criminal enterprises.

apotheon
apotheon

If cell phones are allowed into the prison without regulation, there's no practical way to tap them all. Cell phones in prisons provide a way around the taps on the landline telephones in prisons, thus the need to block them.

AnsuGisalas
AnsuGisalas

Either you jam or you don't; that's a shoot first, ask later -method. If there's a whitelist, then how do you deal with local residents? Either you get to do a whole lot of privacy violation, or you make the local residents' cell phones very desirable for criminals. Either way is bad? An emergency frequency will be found out by criminals in ten seconds flat (ok, maybe it will take weeks, but for this purpose the effect is the same, the outcome guaranteed), then it will be exploited. The point of the phased array system is that it's a high-resolution detection and 3D-localization, combined with a capability to produce highly localized jamming. So it's not jamming anything if there's no reason to.

Steve__Jobs
Steve__Jobs

Why do people not read and absorb other posts before dumping in their own white noise? The previous post #150 implements your idea in more detail.

apotheon
apotheon

Just like the other answers along these lines, what you said is not sufficient to satisfy the requirement for avoiding interruption of service for arbitrary non-inmates within range of the towers.

Steve__Jobs
Steve__Jobs

A lot of people do not seem to be reading the postings and are running aout in circles. It's not a problem. Here are the facts: (1) Network Based Location: Three standard towers can triangulate a cell phone location within 50m resolution. (2) If a phone is determined to be within the prison zone, a white list filter is applied. If the location is determined to be outside, then connections can be made as normal. (3) Civilian phones are unaffected outside the prison and, rationally, only authorised phones will work within. (4) There is no capital investment involved.

raxelsonsr
raxelsonsr

The prison has to spend nothing.All new cell phones will have gps in them. (to locate people)Use the tech in this way.Gps is accurate within 50 feet,so measure the peremiter + 50 ft of prison and have cell tower block all calls in those Long and lat specs,and use exclutions for allowed phones at prison.Allow no calls without gps values.(old non gps types) Walla!

apotheon
apotheon

You seem to have overlooked the part where they want to allow all cell phone communications except those involving inmates.

apotheon
apotheon

The problem with that is that people near, but not inside, the prison will also have to contend with a loss of service. Something tells me the FCC will have something to say about that.

apotheon
apotheon

People in the areas near the prison will also have their cell phones "captured" by the tower as well, though. Problem not solved.

SmartAceW0LF
SmartAceW0LF

The guards, presumably -at least in the collective- are NOT aware of the presence of the cell phone until someone is caught using it. There are basically only 2 ways it could get there within most prisons. It is either brought in by a visitor or brought in by a guard. In the case of visitors bringing one in, this assumes the prisoner it is turned over to can get it out through the "booty room" onto the compound. I shudder to imagine how far up such an item would have to be in order to avoid detection in there! Otherwise it may be left in the visiting room perhaps for the inmate cleaning crew to pick up and deliver to its intended recipient. Surely, there must be a handful of other ingenious ways to get one in and you can rest assured that there are some very crafty prisoners locked up. Having covered 1 of the 2 basic scenarios, one might ask, "So just how does such a device get into a maximum security facility?" You get one guess. Another factor that seems to have eluded this conversation for the most part is this. Prisons come in a wide array of security levels. From camps without fences to holes in the ground with nothing but cameras looking in and nary the sound of another real human voice short of the guards. Now, if devices such as these are making there way into Maximum security facilities, they are MOST likely getting there through someone with clearance. If it is the lower security facilities one might wonder why it is such a big deal to merit this sort of attention. This whole scenario begs the answers to far too many fundamental questions before suggesting reasonable resolutions. Again, this whole thing stinks. Nice little pretext though. Wonder what the real issue is? Hopefully, that answer will continue to elude me after I see who is at the door.

AnsuGisalas
AnsuGisalas

And you still have to get a way to find out which call is from a convict, and which isn't. Phones used can neither be blacklisted or whitelisted, legit users must not be hit by whatever is done. And I don't think these inmates don't care about the price of phones, they're probably stolen anyway, and smuggled in to help gang bosses organize their troops and murderers arrange hits on witnesses. They're disposed of after use to prevent the authorities from getting to the logged data. I think it's safe to say that it's not enough to inconvenience them, either they have to be 100% certain of getting caught trying, or they have to be unable to phone at all. Nothing less will suffice.

apotheon
apotheon

That is what punishment is about Speaking from the perspective of someone who thinks about security a lot, I'd say that while punishment is about stuff like denying common luxury, the criminal justice system should not be about punishment. A far more important goal is the protection of those who have not violated others' rights. In short, I don't give two craps about whether or not prisoners get to talk to their mothers for comfort, one way or the other, but I do care about whether they get to arrange hits from prison, and I care about whether they get out of prison and re-offend.

Steve__Jobs
Steve__Jobs

Try reading post # 150 before spamming us with yet another uninformed duplication.

rockysubu
rockysubu

Well,probably I did not convey that well enough.Whitelisting is a supplement to jamming and not aimed at permitting selected calls to get through the jamming;that quite obviously is not possible.It is to add a layer to the security provided by jamming.In any case jamming implies the Rx is jammed not the Tx.The cell phone will pump out its signal(even when the jamming signal is present !!)which will be picked up by the service provider's tower.It is the signal from the Tower to the handset which will not be captured by the handset as a stronger signal from the jammer is present,thereby preventing handshaking and blocking all incoming traffic. The problem of local residents especially in high density areas is a genuine one.This probably can be solved by using the Home location list of a particular cell/BTS or whatever it is.Non-home subscribers coming in post-handoff will face a problem due to the Whitelist. Some method to resolve this can be evolved. The emergency freq being talked of is not for cellular comm but for walkie-talkie or conventional two way CB radio for example the Motorola GP series,Kenwood etc in the VHF band,pretty far away from the cellular band !! I cannot comment on the Phased array system in question as it is way beyond my league,except that such a system probably will be substantially expensive and require a major engg design effort

jmgarvin
jmgarvin

There would have to be a method in which you could request service quickly and automatically, without allowing the "wrong" calls out. So, between a white list (maybe a list of allowed phones), access to all phones calling 911, and an authentication method (if needed), it seems like this is quite doable. Hell, I do this all the time with our VoIP software, it seems like it should be no different for cell phones. Redirect unallowed phones to some authenticating mechanism.

BrightLibra@Gmail.com
BrightLibra@Gmail.com

You are right, Ansu, on many levels but there must be a "need" for cellular coverage to a prison in the first place. One that I am really unsure of - the guards (and other personnel who are in need of quick communication) should have radios that let them access people very quickly who have resources at hand. Much like the idea of boating without a Marine Band Radio, who would you call if you were sinking? 911 will get you the California Highway Patrol (here in Los Angeles) and they have to transfer you somewhere that can help... IF you know where you are in the first place. I think this is a solution in search of a problem...

Steve__Jobs
Steve__Jobs

Good spot. Thanks apotheon. Would be nice if they heard of Primary Keys :)

apotheon
apotheon

I don't think it's #150 any longer. Using the post number doesn't work very well, because the numbers change as preceding subthreads grow longer.

apotheon
apotheon

Jamming isn't something that affects only reception or transmission. It involves basically blasting the radiation spectrum used by the communication devices you want to jam with noise, decreasing the signal to noise ratio within that spectrum. Since both transmission and reception use the same spectrum, that means that both are equally affected. Jamming, in fact, is effectively what happens when you drive cross-country and leave an area where (for instance) 99.1 FM is a rock-and-roll station and enter an area where 99.1 FM is a country station. As you move from one area to the other, the signal on your radio is garbled, and gradually shifts from one station to the other. This is because the new area's broadcast is saturating the spectrum more strongly than the old area's broadcast, due to the fact you're moving farther from one broadcast station and closer to another. This example involves something that happens to the radio waves in transit, between transmitter and receiver, and if both ends were both transmitting and receiving (as with a cell phone and a service tower) then both ends would be unable to get a clear signal due to the "jamming" effect of the interference. It's not like your cellphone's receiver or transmitter would be affected directly; it's just that what you'd receive would be garbled because of the same-spectrum noise produced by the jammers, and the same would be true of what the tower received from you (or, rather, didn't really receive from you). That's the problem with jamming, really; it's indiscriminate within its broadcast spectrum.

jmgarvin
jmgarvin

Put up signs and make people just deal with it ;-)

apotheon
apotheon

I still don't see how this solves the problem of somebody driving through the surrounding area (for instance) and getting denied service.

AnsuGisalas
AnsuGisalas

Not marking double consonants unless significant.

apotheon
apotheon

You seem prone to typos for the moment. You lost an F in the name Kerckhoffs this time. Ahem.

AnsuGisalas
AnsuGisalas

The missing k was a simple typo, I didn't even realize that before you mentioned it specifically. On apostrophes; I've become more and more audio-minded in recent years, so I actually only remember and "read" the soundshape of a word. So genitive or not, it's going to be [kerkhofs] either way, since there is no opposition of (sound-)forms. But that's me.

JCitizen
JCitizen

Maybe I should take it easy on members who correct for minor English and grammar mistakes, too! In your position, this is important - in my position, I try to make our fellow members feel at home. I hope we are both right.

apotheon
apotheon

you: Kerchoff's moi: Kerckhoffs' In addition to apostrophe misplacement, you also missed the K between the C and the H in the name. That's what'll most likely stop people from finding information about the Kerckhoffs' Principle. (edit: The apostrophe misplacement is more likely to just make it slightly difficult to find information about Kerckhoffs himself, since people might think it's Auguste Kerckhoff, with no S.) As for apostrophes . . . I find that most people seem to have no idea how the rules of apostrophe use work, and as such people muddy up textual communications pretty badly all the damned time. A lot of people claim that it doesn't hurt clarity at all to say something like "Kerckhoff's" instead of "Kerckhoffs'", but I think the reason for that belief on their part is that they don't understand how apostrophes are meant to be used anyway, so every time they see an apostrophe they have to muddle through their lack of understanding of exactly what is being conveyed, whereas for someone (like me) who actually understands how apostrophes are meant to be used, the person only has the problem of muddling through a lack of understanding of exactly what is being conveyed when the apostrophe is misused. It's a case of people not knowing what they're missing, and being unwilling to learn in a lot of cases. Hmph. That was a heck of a digression. Sorry 'bout that.

AnsuGisalas
AnsuGisalas

But, it also reveals that this particular mistake is not uncommon.

apotheon
apotheon

Perhaps it's because I'm used to writing for a wider audience than just the one person to whom I may be composing a reply, I'm cognizant of the effect spelling errors can have on bystanders. In this case, for instance, a silent reader of this discussion might have a really difficult time finding information about this mysterious "Kerckhoffs' Principle" if it's misspelled. Thus, correcting the spelling is not only of use to the person whose spelling error is corrected, possibly helping him or her learn the correct spelling, but is also of use to other readers who may be willing to look up concepts and terms they have not encountered before when they can find those concepts and terms in (for instance) Wikipedia. Misspelled, however, they may not be able to find them. It's not all about you; while you may have known what we were discussing, someone else may not have known, and that person should not be left without the tools to easily learn about it.

JCitizen
JCitizen

I'm not so anal about spelling! =D

AnsuGisalas
AnsuGisalas

That's what I get for assuming I know someone's name from the ring of it... Those "false friends" are a pain, even for professionals.

apotheon
apotheon

s/Kerchoff's/Kerckhoffs'/ His name is Kerckhoffs, and it's Kerckhoffs' Principle.

AnsuGisalas
AnsuGisalas

But the problem is, that prisons aren't all in the middle of nowhere. The towers aren't there for the inmates, with their smuggled in phones and their murderous intentions... the towers are there for the normal people living in the areas in range of the prison. But even then, really, the coverage is as I said of academic interest, because it can be extended and sent in by relay. The comm-units for the guards have to be taken into account too. They can't be using a "secret handshake" or anything like that. Kerchoff's principle must be observed, because organized crime sure as hell will find out how it works and make an exploit if there is a weakness. Or make the same kind of comm-units of their own, or steal them, or whatever else. It's simple and it works, crime lords know KISS.