Inexpensive jammers can block 4G-LTE across entire cities

By on November 15, 2012, 3:30 PM

Happen to have a $650 radio jammer and an inclination to be mischievous? According to Virginia Tech researchers, anyone who does could effectively cripple the 4G-LTE connectivity for their entire neighborhood. Even worse though -- throw an inexpensive power amplifier into the mix -- and suddenly you have a device which can blot out LTE communications across entire cities.

This discovery is likely to be little surprise for anyone familiar with wireless communications; however, the ease with which it can be done alarmed researchers. 

While jamming any radio frequency is simple as overwhelming it with high-powered transmissions -- essentially a denial of service attack -- LTE is far more sensitive to such methods. LTE depends on just one percent of its signal to provide transmission control instructions. By utilizing a programmable radio jammer, hackers can narrow in on control channels and focus their attack, rendering the entire band useless for LTE.

"If you can disrupt that synchronization, you will not be able to send or receive data." one researcher told MIT Technology Review. "There are multiple weak spots—about eight different attacks are possible. The LTE signal is very complex, made up of many subsystems, and in each case, if you take out one subsystem, you take out the entire base station."

With alternatives (i.e. slower networks) being phased out by carriers, researchers worry such an attack could leave the public vulnerable. It wouldn't be just a matter of not getting your email either, but rather an issue that extends to public safety and commerce. Some police departments (pdf), for example, have been flirting with the prospect of utilizing LTE. Another such example is FirstNet (pdf), a proposed national emergency response system also based on LTE.

Researchers said they've identified the problem, but coming up with solutions is another matter. "It’s virtually impossible to bring in mitigation strategies that are also backward-compatible," one member warned. The group has shared its findings (pdf) with the U.S. National Telecommunications and Information Administration (NTIA).

User Comments: 18

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Guest said:

It seems like another case of useless technology only created for profit, and the real solution its new technology almost impossible to exist with backward compatibility....NICE!!!

Timonius Timonius said:

But can you actually carry a jammer and amplifier around in your pocket? >

Guest said:

Yes.... definitely

Seventh Reign Seventh Reign said:

So WTF would you post this story, letting everyone know??? Incredibly stupid.

Scshadow said:

So 650 for the jammer. How much for the amplifier? I'd be happy to pitch in to a "Screw LTE" tour of equipment. I've seen LTE ads blasted at me constantly for many years and know that for many years to come I'll still not have LTE. I'd love a little payback for me having to suffer through their ads.

dennis777 dennis777 said:

So cable lines are the most reliable connection.... ehem "fiber optics"

jobeard jobeard, TS Ambassador, said:

Definition of evil: doing harm to others even though there is no benefit to ones self - - GRRRR

Scshadow said:

Definition of evil: doing harm to others even though there is no benefit to ones self - - GRRRR

So as long as there is a benefit for yourself, it isn't evil? I don't recommend you help with making any dictionary of any sort.

Wendig0 Wendig0, TechSpot Paladin, said:

So WTF would you post this story, letting everyone know??? Incredibly stupid.

Perhaps so they have a chance to correct the problem?

Guest said:

Great news! /s

just when LTE 4G is being rolled to consumers.

let's re-use morse code.

hack it you... you... you joy riders...

Guest said:

No matter what one man creates another man will try to destroy it. With every technology advance there is a weakness that someone can take advantage of.

If we are in an all-out war, then this might be an issue however say Joe Troublemaker decides to jam your local network and forks out $650 to do this. I don't think it would take very long to find and remove the jammer as it will be sending a very strong signal out.

jobeard jobeard, TS Ambassador, said:

let's re-use morse code.

. . . - - - . . .

1 person liked this | lipe123 said:

And why is there no mention of the legal ramifications of broadcasting crap into regulated channels without a license? not to mention doing so at a much higher power output than the legal limit?

If you have any experience with wifi networks you'd know its quite easy to narrow down where interference comes from especially if you own various towers all around the area.

So yes this is a obvious downside to any wireless tech but you WILL face some intense fines/jail time for doing this for any length of time.

We could write a similar article showing how a pair of dollar store side cutters can cripple cable networks =P

jobeard jobeard, TS Ambassador, said:

Yes the FCC can make life difficult and broadcasting more than 100mW is a violation.

But if these 'people' would stoop to jamming they wouldn't worry about it any more that the bootleggers during prohibition

Tygerstrike said:


Just because someone would be smart enough to put a jammer together, doesnt mean they are BRIGHT enough to calculate all the variables of the act itself. Mainly because with all that equipment at their disposal, a cell company could narrow it down to almost an exact address. Yes on the surface it would seem foolish to post this article online, however any information is good information. Its just how its used.

So, THANK YOU RICH!!! This little tidbit of info might stop ppl from acting stupid.

jobeard jobeard, TS Ambassador, said:

So, THANK YOU RICH!!! This little tidbit of info might stop ppl from acting stupid.

:giggle: Murphy was an optimist too

Guest said:

Anyone can do this... same for radio.

Problem is, doing so is a Federal offense & FCC is extremely harsh. You will see 20 years if caught.

TJGeezer said:

So WTF would you post this story, letting everyone know??? Incredibly stupid.

Here's an idea - we can blame this engineering design problem on tech news sites that report that a publicly available MIT study exists about the problem. That'll help!

Or will it...

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