Bluetooth Channel Sounding: The Next Leap in Bluetooth Innovation | Hacker News Reader

Bluetooth Channel Sounding: The Next Leap in Bluetooth Innovation

embedded.com

82 pointsJoachimS45 comments

I am pursuing a PhD in indoor localization, and UWB is still far superior. That is the reason why major phone companies still include a UWB chip and are not switching to BLE 6.0.

I have compared them, and because BLE is a narrowband signal, it is highly susceptible to Non-Line-of-Sight (NLOS) conditions compared to UWB.

I also attended a prototype presentation by a large European silicon company. I noticed that even in their demo, BLE did not achieve 30 cm accuracy, but rather hovered around 1 m.

I have only tested PBR and RTT ranging with a simple Kalman Filter, so maybe someone has found a clever combination of these data sources (I hope).

Are there any good alternatives? We need something to prevent replay attacks on app based phone far keys..

Cool, I worked on indoor localization, particularly with RTT, at Google for many years :)

Maybe we can get in touch, I am curious to have a more senior perspective on the indoor localization!

Is there a good list of cars that support UWB? Seems like a requirement for my next car...

All the new car have the keyless option and use UWB to open and close.

New devices, such as Pixel 10 already support channel sounding. Basically it's alternative to UWB. One phone sends signals on multiple frequencies, another receives them. Obviously devices should be connected via BT. Also tracking people already works with BT/WiFi RSSI (signal strength). Channel Sounding works better because it works even when the signal line of sight is obstructed, for ex. headphones lost under pillow.

How do they compare in actual use? I have a Pixel 6a connected to $40USD bone conducting headphones and the range and punch-through are incredible; the phone is sitting in the living room playing music and I can almost make it to my mailbox at the end of the block (about 3 houses away) before it starts to degrade or cut out.

Do these alternatives compare with just how well UWB serves regular, normal daily activity like this? Because to me, what I have is absolutely excellent in use with daily routine.

Edit: It seems I'm wrong. Channel sounding requires an encrypted connection. It's not something that can be done between a passive device and your phone.

It will allow things like secure entry (walk up to a door and it opens, be near your car and you can open it), finding your devices (lost keys, headphones, remotes, etc.), auto-unlocking for your laptop, and more.

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This is a really cool technology that is going to allow essentially indoor GPS. Imagine going to a mall, and you open a map on your phone, and it immediately knows where you are to under 1m error.

Do you still need "satellites" installed indoors to work? Because then you'd have to convince every business that this cost has a direct positive effect on their sales.

A lot of brick and mortar stores are based on the assumption that a lost customer will buy more things, so I don't see this happening.

Think about how this information could be used. As a store owner you can precisely track movement of customers and optimize the shop layout.

BT hardware is also rather affordable.

You're already tracked like that. I was building solutions to do it well over a decade ago. One customer was well known for their mouse themed hats. A famous hotel brand in a well known casino city used it to track employees instead. I no longer do that for obvious ethical reasons.

There may be a rare few legitimate uses for improving the accuracy, but it also makes those privacy nightmares worse.

My previous employer already had a product offering that could do this for a better part of a decade by triangulating with WiFi/BLE and cross referencing with surveillance footage. It was deployed in malls and retail chains.

It generated interesting information, but not interesting enough to be profitable.

We weren't the only ones with this capability either, most major retailers had this level of analytics through surveillance footage that previously existed for loss prevention purposes. Then simply link the data to a rewards number or credit card and you got a stable tracking identity.

I've worked with a major retailer on similar backend systems and can echo the post above - all of them are running these systems and they almost never discuss the specifics (until someone like Walmart sues Everseen and we get a glimpse behind the curtain from the court documents).

If you go to an org's website offering these tools (eg, Everseen mentioned above, RetailNext, etc), they don't directly advertise the full breadth of their capabilities until you have them in a room for a sales pitch. They can combine multiple data streams such that an individual can be traced throughout the store via cameras, wifi, and bluetooth, which gives the retailer an opportunity to sell that information. Did a customer pause in front of the corn chips but then decide not to buy? Print them out a Frito-Lay coupon at checkout and see if you can't get them next time, and Frito-Lay will pay you to do that.

That's so cursed. I suppose since the source of the money here is the manufacturer, this only happens in major retailers with large shops?

Do you know if smaller shops in india/asia also make use of this?

I have no first hand experience outside of North America so I won’t speculate. There is a cost of entry so you need to be moving enough volume in a market already working on razor thin margins. I’d expect that this means it’s only for the regional/national players here.

Ah ok so just to confirm the providers charge the store per user entry? That gives me a good idea of who would go for it. Thanks

Sorry, "cost of entry" meaning that the software and the supporting hardware platforms makes it cost prohibitive for a small org that isn't moving a lot of volume from their shelves. Grocer margins are razor thin already.

> loss prevention

So preventing theft?

Theft is only one cause of loss. Stocking/admin/counting mistakes, accidental damage, spoilage, or simply people moving stuff around or misplacing items so they're not where it's expected all fall under loss.

The industry tends to use the even harder-to-understand term "shrink". Not always theft, just any loss of product versus what the books say they should have.

No, loss prevention. :)

"Theft" is such a value-loaded, moralizing term. It collapses a wide spectrum of socioeconomic realities into a single criminalized label, ignoring the structural inequities that often shape people's choices. When we say "loss prevention", we're deliberately reframing the conversation away from individual blame and toward systems, environments, and institutional responsibility. Loss prevention isn't about vilifying people - it's about acknowledging that harm occurs within a broader context. It centers the idea that organizations can design safer, more equitable spaces that minimize material loss without resorting to punitive narratives rooted in classism, racism, and centuries-old assumptions about who is "dangerous". Calling something "theft" externalizes accountability onto the most vulnerable actors; calling it "loss" recognizes that institutions have agency, too. And preventing that loss focuses on proactive, compassionate strategies rather than reactive punishment.

Poe's Law is strong in this one.

https://en.wikipedia.org/wiki/Poe%27s_law

This message is approved by the Ministry of Peace.

I'm dumber for having read that.

La propriété, c'est le vol !

-- Pierre-Joseph Proudhon

I work with retail stores who do exactly this in a number of different ways! Many chains are already populated with all kinds of BT sniffing(?) equipment. At least one pings RFID tags in everything every 5 seconds. It’s wild.

And guess what, that shop layout is not going to be optimized for the customer's convenience, but for the shop's profits. These kind of solutions tend to converge on the 'Hotel California' model: you can enter, but you can no longer leave.

Indeed, screw IKEA.

Maybe US IKEA is different from European ones, but there are literally arrows on the floor that guide you through the whole thing? Follow the arrows and you're out.

No, they don't guide you to the exit, they guide you past the collection.

The whole point is that the thing is set up like a very long serpentine track so that you 'see everything' rather than that you can go to the one thing you want and then to the cash register. This is because they - rightly - figure that if they can keep you in the store longer and expose you to more stuff you might buy more.

You can enter the warehouse directly through the register area. No one is stopping you.

Oh, that's a neat hack. I will definitely try that next time. I have a bad leg (bike accident) and the extra walking really pisses me off. I don't need a stick or other help but I do economize on unnecessary walking on hard surfaces. Thank you. Ikea has killed all viable competition here so you can't really get around them.

Another tip, there's usually an "offramp" in the later part of the showroom grand tour that goes to the cafeteria section. You can also jump straight to the cafeteria from the entrance at most ikeas I've been to and enter the showroom there to get a shortcut to the lamps and things.

The IKEA near me also has shortcuts, but if you go in through the “loading dock” you should be golden. We also have an even closer IKEA mini location where you can order from a tablet and have orders brought from other stores.

Every IKEA around here also has various shortcuts that you can take at any time. Even from entrance almost directly to the warehouse. These are also indicated. So it is a choice whether you want follow the whole route for inspiration or not.

> No, they don't guide you to the exit, they guide you past the collection.

I did not claim they guide you to the exit. What I said is that you don't get lost if you stay on the path. A scenic route to the exit is still a route to the exit.

Also: if you want to get to an actual exit it is mandatory (at least over here) to have clearly visible, emergency exit signs so people can get out in case of fire.

I am not afraid of getting lost. I'm annoyed at having to walk more than strictly necessary on account of a less-than-perfect leg.

I mean IKEA offers a service where you can pick stuff online and collect a d does even do home deliveries. Meaning if you have to avoid walking it is certainly possible with them.

I can imageine that. Although not using Channel Sounding, as it has a accuracy of +/- 200mm according to TFA. Which is still very good, though.

I don't follow your reasoning. (+-)200 mm is better accuracy than 1000 mm.

1m? 1mm? Apparently I was seeing double

In case you're not familiar with the metric system: 1m is 1000mm. In other words, one millimeter is one thousandth of a meter.

What an unfortunate name.

https://www.urbandictionary.com/define.php?term=sounding

    > Sounding is the act of inserting a metal rod into your urethra.

Sounding in this usage is far, far older than the sounding you're talking about.

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