Comment by jpm_sd | Hacker News Reader

Comment by jpm_sd | Hacker News Reader

I recently learned that USB3 is not only badly designed, flaky and unreliable, it is also an EMI/RFI nightmare. This is woefully understated in the article when it says:

"It's hard not to generate harmful interference."

We built a prototype sensor payload that included a USB3 external hard drive. Started suffering broad spectrum interference that stomped all over L-band (Iridium and GPS) reception. Made the entire system unusable!

Some references on USB3 noise:

USB 3.0 Radio Frequency Interference Impact on 2.4 GHz Wireless Devices (by Intel) https://www.usb.org/sites/default/files/327216.pdf

see especially Figure 2-2: "the data spectrum is very broadband, ranging from DC to 5 GHz"

USB 3.0 Interference - Cradlepoint Knowledgebase https://customer.cradlepoint.com/s/article/NCOS-USB-3-0-Inte...

"USB 3.0, or SuperSpeed USB, uses broadband signaling that can interfere with cellular and 2.4GHz WIFI signaling. This interference can significantly degrade cellular and 2.4GHz WIFI performance. Customers using cellular networks or 2.4GHz WIFI networks near USB 3.0 devices should take measures to reduce the impact of these devices on their network connectivity. Please note that interference is generated by both the actual USB 3.0 device as well as its cable."

From my own experience, it is very hard to engineer a device that can run WiFi full speed along with USB3, especially something like a smartphone, or tablet, where USB3 pins come out right out of the SoC.

In fact, we tested existing laptops on the market for WiFi/USB3 coexistence, and only 1 laptop ever made it flawlessly. It was a quite old Sony Vaio, where USB3 lanes were physically put under an RF shield from controller to the port.

Is this a uniquely USB3.0 problem? I've been in the consumer electronics spaces for 10 years & from the very beginning I would hear reports about problems for 2.4Ghz WiFi any time you were transferring data on USB (& usually EEs try to tackle this with shielding if USB + WiFi coex is important). I have not heard of this as uniquely new to USB3.

I have never heard of interference with Iridium & GPS for USB2/3 and I worked on a team that was responsible for GPS at Apple, but it's entirely possible there's shielding needing to account for this & I just wasn't closely involved in it. If this were actually an unsolvable problem though, I would expect CarPlay & Android Auto would have a problem when you use your phone for navigation & start playing audio through USB. Maybe that's not enough traffic frequently enough to generate the noise needed to make it unusable, maybe the EE problem you were having was different, or maybe there's just good shielding in phones to avoid this as a problem.

> Is this a uniquely USB3.0 problem?

https://usb.org/sites/default/files/327216.pdf

Paper by Intel about USB 3.0 interfering with 2.4 GHz WiFi. The fact that the USB-IF hosts this paper on their own site seems to be a strong endorsement of their conclusions too.

It is worth noting that the RF noise generated by USB 3.0 covers a fairly wide spectrum from basically zero up to the mid-4 GHz range, but it gets discussed mostly in the context of interference with 2.4 GHz because most USB 3.0 capable devices don't have any other radios in that range to interfere with.

I didn't say USB3 doesn't cause this interference. I was saying I don't recall this being a uniquely USB3 problem (unfortunately all I have is my memory to go on here that we had desense issues with USB+2.4Ghz when I worked on the Palm Pre & Jawbone Jambox).

Given the report is 8 years old, I find it hard to believe this isn't an active thing that's designed around. Hell, you can buy USB3 WiFi dongles that do 2.4 Ghz. If this were a critical flaw that's unsolvable such a device wouldn't be possible to build. Even Table 4-2 indicates different mouse models have different performance characteristics, indicating not all 2.4Ghz devices are similarly sensitive to the problem.

My Lenovo 2.4 GHz mouse and MS Sculpt keyboard suffered from interference when the receiver dongle is plugged directly into a USB 3 hub with other USB 3 devices, and this is a well known issue. I fixed it by buying a shielded usb cable to move the receiver away from the interfering USB 3 hub and closer to the keyboard/mouse themselves.

Same issue with logitec mouse, mbp, usb3 hub dongle, buying an old school 4 port usb2 hub and running the cable away from the dongle, problem solved. Gotta love the future

It's not just USB 3, Thunderbolt 3 also has an interference problem. I had to get a 1 foot extension cable for my Logitech Unifying receiver plugged into a CalDigit Thunderbolt 3 dock to prevent my mouse from freezing. My wife had to do the same with her Unifying receiver plugged into a LG 5k Thunderbolt monitor.

RF coex will always be an issue, and it's especially bad when you bury a dongle with a tiny inefficient antenna in a mess of shielded high speed data cables (thunderbolt, displayport, ethernet, USB, etc.)

I had to do the same with my MS sculpt keyboard and Lenovo wireless mouse.

For years now I've used a logitech wireless dongle paired to mouse+keyboard.

During all those years the only way I could avoid random drops is by connecting the dongle to usb 2.0 ports.

I've had this issue both on a old dell l502x laptop and also now on my current asrock x370 motherboard which doesn't even have native usb 2.0 ports.

Sad to know this is actually a design issue, and thus may repeat on any computer I acquire in the future.

your dongle wouldn't use the USB 3.0 SS lines, they would be inactive, so it is not active interference that is the problem here.

I knew it! I had a 'gaming' type very comfortably shaped mouse but it used a specific 2.4ghz adapter. Any time I did a large file transfer over USB3.0, any flash drive replicated the issue, the mouse would become jumpy and unusable plus WiFi speeds dropped to maybe 10% for the duration of the transfer. I ended up giving the mouse to a friend and going back to my first gen MX Master.

Also, if the mentioned "key" used on each end is well-known or the xor approach is not cyptographic in quality, then anyone could listen to this EM output and compromise your "hard wired" data which you'd (forgivably) expect to be secure, a la TEMPEST. Depending on the strength of the signal, could be a serious problem.

Way back when, I thought I remembered that usb3 or thunderbolt was going to be an optical interface, but I guess that was too tough in practice. Would have been nice though to avoid EM interference issues.

I think it was Corning who put out a 200m thunderbolt 2 fiber cable

They exist but are fairly expensive and are passive.

Experienced this first hand. Had a crappy WiFi connection at home, started to investigate and found out that signal qulity degraded a lot when my Seagate SDD was connected on USB3.

My desktop has really flaky WiFi. Its WiFi adapter and a few peripherals are connected using USB3 ports. I just thought I was too far from the router (it's a room away through two walls). Is it possible switching them to the 2.0 ports could make my signal better?

Maybe. Although switching wifi router into something like 802.11b-only or a-only mode and selecting a fixed least busy channel might be a better long term solution, as USB3 isn't the only source of EMI.

Why exactly do you recommend archaic WiFi standards that are long gone?

It's a simple way I know that significantly improves reliability of wifi in most circumstances.

I challenge that 802.11b is more reliable than 802.11n, which offers MIMO. But even if that was true, the speeds of 802.11b are abysmal for todays standards.

I'm not aware of USB interfering with anything 2.4Ghz. If you're on 5Ghz I've not seen USB2/3 coex be a problem. Unless your dongle vendor did a bad job, USB dongles should be designed to minimize the impact of this interference because all they do is WiFi + USB (i.e. shouldn't matter if you are on 5 or 2.4). That being said, it's a simple thing to try so why not?

Does "flaky" here mean connection going in & out vs inconsistent & bad speed?

Assuming we're talking about speed rather than the connection itself, two walls can be a challenge if you're on 5ghz depending on the quality of your router & dongle. Do you have any old devices on your network? Your WiFi router will run at the speed of the slowest client. Can't recall if camping is a problem - I'm less clear about the details here, but it should be. If your 802.11AC dongle is on the same frequency as 802.11N, performance will be degraded off the bat so consider moving those devices onto a different frequency if you have a dual-band router (e.g. wireless printers or older wireless TVs can be causes).

If the connection itself is flaky, check if the RSSI is really bad. Anything >= -70 dBm is good & anything <= -80 dBm is pretty bad. Note the negative sign. -90 is worse than -80. If you're on 2.4Ghz you could also be having issues from poorly shielded electronics (e.g. old microwaves) or cordless phones.

Hope this helps!

> I'm not aware of USB interfering with anything 2.4Ghz.

https://usb.org/sites/default/files/327216.pdf "USB 3.0 Radio Frequency Interference Impact on 2.4 GHz Wireless Devices"

Please give a generous reading for what I wrote. Off-hand, I was referring to any WiFi dongles he would have likely bought. Not an 8 year old report of problems encountered at the time that's not even exploring self desense as a problem.

Yes, USB 2 or 3 can cause issues for 2.4 Ghz if you don't shield your components properly. Are you saying that WiFi dongles, whose only job is to connect to these networks, isn't shielded properly?

I had to wrap a USB 3.0 cable in tin foil once when I realized it was causing the issues I was having with wifi

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