Infrared may no longer be a punchline, as IEEE approves 9.6Gbps wireless light
theverge.com
theverge.com
And just like 802.11be and 802.11ax, I had to read up on the actual Spec again to understand WTF is going on instead of relying tech reporting. And this isn't just a problem with reporting, the actual PR of Li-Fi cant even do half its job.
I'm a big fan of using simplified IrDA in 2023 in hobby electronics. But I don't see a smooth path to 9.6Gbps.
1Mbps to 10Mbps is already exhausting for me to think about.
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Is there any industry chip with planned development to handle this standard? Finding a damn LED and Photodiode that is guaranteed faster than 20ns to feasibly handle 4Mbit is horrifying. Let alone the signal processing circuits (I think you need 20Mhz OpAmps which isn't a 6001 or lm358 if you know what I mean) or FPGAs needed to handle this relatively low speeds.
Or are we doing some kind of multi-frequency multi LED thing? Are there any LEDs or Photodiode that can emit and detect such a narrow band? What are the sources of IR noise to mess with those frequencies?
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Oh, but 115kHz is plenty useful for a hobbyist and I highly recommend people playing with that.
https://www.leuze.com/en-us/products/optical-data-transmissi...
If we use Wi-fi like processing (256-QAM and the like), we'll only need 12.5 Mhz-class LEDs and photodiodes to communicate at 100 Mbit. (assuming 8-bits per 80 nanosecond or whatever). I'm pretty sure that cheap LEDs with 50 nanoseconds aka 20MHz speeds, as well as analog components with high-gains at 20MHz (I dunno, a 1GHz bandwidth-gain, giving x50 gain at 20MHz) are all possible.
I think the article's claims of 9.6 Gbit are so absurd however, that I'm having a great amount of difficulty seeing how it gets there.
I admit that I wasn't aware of the automation IR links that you posted. I'm impressed that IR has gotten that good today, but its not so good that its become unbelievable. The 9.6 Gbit headline on this article however is just absurd at face value. I really need to see a physical demo before I'll believe something like that.
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I know that IrDA is a 90s standard made for far slower LEDs and components. But its a good baseline for thinking about the issues that occur in the space of light-based communications.
I like 38khz modulated IR more than 115kbps, you can get really good range at low cost and power, without high parts count, and if you have large amounts of data rather than just stuff that takes advantage of directionality, you can do it over Bluetooth for cheap.
Never got a chance to play with 115kbps though, seems like it could be pretty cool, but I'm not sure what I'd do with it.
Isn't that like, laser speeds? Not overhead LED speeds. And over the air? Not inside a fiber line?
This is basically a 10Gbps standard for fiber lines except over the air. All those issues need to be solved without the guarantees or isolation that fiber optic lines provide.
That's just transmit. Receive has to deal with the same issues, amplifiers and other electronics that move at the requested speeds.
Nicely isolates narrow band noise.
Then usual high order QAM in the subcarriers.
256QAM gives you 8bit per symbol.
So it'd only require 125MHz of modulation bandwidth...
Is that a 400ps rise + 400ps fall time LED? Picoseconds?
Or the use of like 8192QAM or something incredible?
I'm sure that this idea is more of a fun hackaday-style gimmick (i.e. not productionizable for various reasons), but would be fun to see.
But then why not just use wired Ethernet?
So I run an ethernet cable across the floor, and it's not great.
I also think VR/AR use cases may benefit from this eventually.
I need to look into newer generation Ethernet over power to see if it’d work better than the aging pair of plugs I purchased a number of years ago.
(There are none on the west coast: https://commons.m.wikimedia.org/wiki/File:Map_TDWR.svg)
And then more rarely, certain military airports.
Both my phone and computer supports 6GHz, but it's still hard to find a reasonably priced router.
And my range it atrociously bad.
It’s an old building, and I live on the top floor just below a roof with assorted antennas. I think there’s some microwave gear up there that would explain my issues.
I’ve wanted to do a site survey for awhile to figure out what’s up, but have just lived with the Ethernet cable across the floor.
Way back when I was still in university, if I would walk out of my room and close the door (which would put a few cm thick wooden door, some plaster wall and about 14m between me and my router) I would already have a significant reduction in connection strength.
Even with the ridiculous walls Americans use for their homes, there is just no way a neighbors 5GHz signal is strong enough to cause significant distortion. And if there somehow is, there is enough room on the spectrum to choose a different band.
Thinking on it, almost all civilian microwaves also only operates at around 2.4GHz. And since you mention sudden spikes, I would check for radar interference and if you are on a band that’s radar-assigned.
I spent a number of years as a network engineer working with consumer microwave gear, most of which was in the 5.2-5.7 GHz range. There is plenty of this stuff around.
And I’ve seen what a poorly aligned backhaul can do to the wireless networks in the vicinity.
That said, I’m not committed to a specific reason it’s not working well, it’s just not. The point was that wifi is not a good option for me for some use cases given the apparent spectrum use here.
I think it’s probably a combination of factors since I live in a dense city. Radar is certainly a possible factor.
This is a recurring question and one often answered by “people rent houses/apartments and can’t just run cables through the walls”.
I’m not all that sure what I’d use this specific technology for over Wifi but I can understand why people don’t use wired Ethernet.
When everything else fails, ask an RF engineer. Metal is for RF like glass for light.
Already this is a problem as I have 1.Gbit internet.
Edit: I am silly and wrote Mbit instead of Gbit.
I believe you when you say you can't replace them, but I'm curious why? Every wire I've ever seen run through concrete was in a conduit that could have replacements pulled through it. Did they just run the wires and pour over them?
The obvious downside being the extra expense of media conversion.
also dear god I hope it's a typo and you meant 1Gb
You want to stick with moca 2, and there might be some gotchas with older coax wiring, but I previously ran it for years without issue.
Traced the cables and the only splitter I can find is a moca 2 aware one, and the coax cable that would have been used for cable internet is unplugged so that's not interfering.
Nice when it works, real pain to troubleshoot when it doesn't.
This fixed some (probably modem specific) problems where internet would randomly drop in the presence of moca.
2.5Gbps isn't even going out of spec for cat5 and should go the full 100 meters.
To connect the networks between the two buildings, they had a laser connection set up in the widow's walk on the buildings. It worked great except when it was foggy or raining very heavily, or when the marina moved a sailboat so that its mast blocked the beam.
Office spaces are going to eat that shit up. They are already running Ethernet everywhere, and they already have many wifi access points. This is probably lower-crosstalk, faster and more localized than wifi.
If the IR is bright enough, it might even make sense to put a NIR camera in every access point so it can double as an unobtrusive security camera, and/or track devices (for beam-forming, forensic information for physical security staff, etc.).
Iphones have some weird feature to listen for coughing or water(?) We already have door bells and door knockers sending out audio signals. (Video doorbells are great but knockers are more reliable.) Lots of devices in the home make identifiable sounds. Combined with the security footage you could generate a film of you using your wireless drill, every time you look in the fridge, open the front door, when you shoot someone, etc "vacuum cleaning the movie".
The vacuum cleaner can be asked for a status report, its serial, build date etc, how full its bag is utilizing a human friendly machine readable audio signal.
It seems much more secure than evil men silently communicating with your devices over the internet.
I think we are onto something here.
Would love to know if I am wrong here though! It seems very interesting.
Light bounce also works, so if you are in a typical room the walls also become antennas.
I could see it being supplemental though. Wifi and this sorta like anycast
I can't really see it totally replacing WiFi though. It's hard enough to get a TV remote to work outside in the shade - getting higher-bandwidth IR-based WiFi to work outside in the sun seems... ambitious?
Or to have a desktop computer across the room from a display and be able to switch displays.
They said it was a security requirement - does seem extraordinarily elaborate. It feels like using wires could have been a simpler answer...
Do mobile devices have to have small light bulb (like infrared) to support bi-drectional communication? It would be too big for modern smartphone though.
It wasn't nearly as fast the advertised speeds mentioned in the article.
Hopefully it doesn't take much to grasp the benefits of ethernet without a cable directly to your device at all times, right?
The actual device speeds is already way lower than what is touted in the title, so at the end of the day it would be less practical than plain wi-fi from an antenna in your room (except if you're really affected by other longer range signals that touch even the 5Ghz band)
The advantage of LiFi over WiFi is that don’t have to deal with interference. The light is confined to the room when WiFi can go to neighboring apartments. The downside is that need devices in each room. If they can get speed higher, within the published ranges not the crazy one, they can do same job as WiGig.
Another advantage is that light diodes and receivers are simple and cheap. My guess is that it is easier to scale LiFi to higher speeds or make super cheap. But that may only work for special cases.
I wonder how easier this will make things for them...
Wireless is notorious for quoting numbers that include protocol overhead and assume a near zero noise and congestion environment. The typical layer 7 throughput of 802.11 is about half of the link rate. Of course it goes down from there without line of sight in the same room.
This would be nearly 4X that.
This new optical standard is only about 50% faster than the now-ancient copper SATA standard of 6Gbps. It has stuff-all reserve for future development!
Every time we have one of these new standards, Wi-Fi whatever, they are just a bit above the previous standard and never at the limits of the tech. There is never enough reserve to give them decent longevity. It's as if those manufacturers involved in setting standards were making a standard that would be quickly obsolescent—that is, they'd guarantee ongoing production/sales without much effort.
It's been such a consistent problem for so long that it has shades of the Phoebus cartel about it. As always, the user ends up paying more because of premature (planned) obsolescence.
you are surprised that free-space optical transfer over many(?) meters is "only" 50% faster than data transfer over <1m carefully constructed differential coax-pairs?
The link sp332 has provided says it all, reckon it supports my case.
Which wasn't what the general public thinks it is and, much like equating short-run in-device transports with lossy, room-distance ones, is a good signal that one is comparing apples and trailer trucks.
So the WiFi becomes the transport layer in the OSI model. It's the throughput data rate that matters not the type of devices that are connected at either end of the link (nor the protocol by which they're connected). .
"common household LED light bulbs" is pretty ridiculous." Likely so, but all we have to do for 9GB/s is to use the transmitters and receivers used in standard commercial fiber optics (or a suitable adaptation thereof) and we'd romp home.
It is the same for every new technology. It was the same with 4G, 5G.
In DE mobile operators do not offer HSPA at the same time with 4G so you cannot compare how crap the 4G is.