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Wireless Networking Communications IT Technology

Location Finds Bluetooth, Ultra-Wideband (eetimes.com) 32

An update of the Bluetooth specification released today enables location services accurate to within 10 centimeters thanks to a new direction-finding capability. From a report: It arrives as a separate draft standard is nearly ready for an even faster and more accurate capability using ultra-wideband (UWB) radio, geared for use in smartphones. Bluetooth 5.1 describes ways to determine location using multiple antennas at either the transmitter or receiver. It uses measures of signal phase and amplitude to measure location, though profiles for application developers are still being finished.

In mid-March, the IEEE 802.15.4z standard for UWB should be in a stable draft form, opening the door for silicon designs. It enables location measures within a single centimeter and resolves in a nanosecond, a rate faster than Bluetooth. Smartphone giants Apple and Samsung have been active in the .4z meetings also attended by Huawei, leading some to suggest that the capability could be integrated in handsets within two years. NXP has also been active since the group started a year ago, giving rise to speculation that UWB could come into phones though an integrated NFC chip.

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Location Finds Bluetooth, Ultra-Wideband

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  • I understand the summary but I can't figure out what the headline is trying to say. Anyone got any ideas? "Location Finds Bluetooth, Ultra-Wideband"
    • by rossdee ( 243626 )

      I think its meant to bw:

      Bluetooth finds location.

      Probably translated from some alien language

    • by Nidi62 ( 1525137 )

      I understand the summary but I can't figure out what the headline is trying to say. Anyone got any ideas? "Location Finds Bluetooth, Ultra-Wideband"

      Sadly, that's the headline of the article itself, as well. The subtitle is "Bluetooth waits for profiles, UWB gears up for smartphones". From what I can tell it means that Bluetooth and UWB can now be used to determine location. I think the author was trying to be clever?

  • Is this another optional part of the spec? A number of nice BT5.0 features are optional and not highly adopted. Basically useless.
  • by swillden ( 191260 ) <shawn-ds@willden.org> on Monday January 28, 2019 @12:24PM (#58034866) Journal

    What's even better than the distance measurement is the fact that the ranging process includes a secure key derivation protocol. The two radios that participate in the "secure bounding" process, as it's called, emerge with both a highly-accurate range estimate and a shared secret key. Eavesdroppers can't easily compute the shared key (I haven't actually looked into the details of how this works), which means that if subsequent communications are encrypted and authenticated using the shared secret plus another mutual secret, relay attacks become very hard.

    Suppose we have a secure authentication protocol that we only want to operate at close range (say, unlocking your car). Without precise ranging we have two problems. The first is that the protocol may be carried out at a longer range than you want. For example, unlocking your car in your driveway when you're in the house. Precise ranging by itself solves that problem. The second is that an active attacker may perform a relay attack and carry out the protocol at an arbitrary distance, such as unlocking your car in the mall parking lot when you're walking around the mall. The relay is performed by putting one radio near your phone and other near your car and relaying messages between them.

    Note that without secure bounding, cryptography can't solve the relay problem because the attacker doesn't have to be able to read the messages, just pass them back and forth. And precise ranging doesn't help because your phone will measure the distance to the attacker's first radio and your car will measure the distance to the attacker's second radio. You can try to do something like have each side encrypt its distance measurement and send it to the other side, but that just means the attacker has to be careful to get both of his radios about the same distance from yours.

    But with secure bounding, each pair of actually-communicating radios will compute a distinct session key. The attacker will know both of these, but if your phone and the car both securely combine the bounding-derived session key with a secret the two share and the attacker doesn't have, the result will be a shared session secret which will only be identical if the phone and car are actually communicating directly.

    • Thanks for an excellent explanation, very helpful.

      By the way, there's an amazing video of a relay attack on a Tesla, sitting at 1.4m views:
      https://www.youtube.com/watch?... [youtube.com]

      • Yeah, I've seen that. Pretty cool attack, and very professionally executed. Tesla has added an optional PIN authentication to limit the risk, but that makes their RF key system about as inconvenient as inserting a physical key into a keyhole, which sucks. UWB distance bounding provides a solid solution to this problem, both more convenient and more secure than a physical key.
  • by Locke2005 ( 849178 ) on Monday January 28, 2019 @01:00PM (#58035142)
    Accurate enough to be used in VR controllers?
    • ..VR controllers
      Well, that answers one of my questions about this, at least: what this would be useful for.
      True, if you have a constellation of at least 3 transmitters/antennas, preferably spaced about 120 degrees apart, then you'd at least have a 2D position fix within the coverage area, and if it's really centimeter accuracy, then that's probably close enough for consumer VR applications, although more than 3 would be better. Put them at different 'altitudes', and you'd likely have enough for a decent
    • The summary says "to within 10cm". VR controllers generally need millimeter positional precision to feel natural.
  • UWB was supposed to be the new PHY scheduled for bluetooth 3.0, but the initiative was shot down by a patent troll.

    Now, Broadcom said that they are ready to give them a battle. With such a strong backer, I guess it will be a hit this time

  • So now I can find where I left my bluetooth-enabled smartphone...
  • 1. What TFA is describing sounds an awful lot, if I'm not mistaken, like the same techniques that GPS uses to acquire a position fix, except on a very much smaller scale, due to the extremely limited range of Bluetooth. A 'constellation' of Bluetooth 'satellite' transmitters within a defined area could be configured with appropriate 'ephemeris' data describing their physical situation within that space, which combined with the techniques described, would provide a very accurate position fix within that spac
  • I tried playing around with various Bluetooth devices (Tile, etc) and an Arduino to see if could get something like bluetooth triangulation working for a pet project. The best I could come up with was an RSSI measuring scheme that sorta worked line of site, w/out movement but went to heck with obstacles and very little movement.

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