Adopting the photonic terahertz technology route, that is generating terahertz signals through two higher-frequency lightwave beat frequencies, a single-wavelength net rate of 103.125Gbps and a dual-wavelength net rate of 206.25Gbps was achieved for the first time in real-time wireless transmission, the laboratory said. <end quote>
Why not just modulate the LED street lights? ?
Good idea. Of course, that limits the use to night only when the lights are on. Wait a minute - we could have IR leds for street lights which would be on all the time and everybody gets IR-sensitive nightvision glasses for use when it's dark. Problem solved!
Is it 1 April already?...
You cannot send data on a single-wavelength. As soon as you modulate it it is no longer a single-wavelength.
Sylvia.
On a sunny day (Thu, 6 Jan 2022 21:55:49 +1100) it happened Sylvia Else snipped-for-privacy@email.invalid wrote in snipped-for-privacy@mid.individual.net>:
Right but a few Gbps sidebands on such a high carrier would look like a narrow peak in the optical spectrum to the casual observer.
On a sunny day (Thu, 6 Jan 2022 08:03:03 +0000) it happened Jeff Layman snipped-for-privacy@invalid.invalid wrote in <sr67no$lh6$ snipped-for-privacy@dont-email.me:
Leave those on.
I was reading that 'meta' VR just died..
English is April 1, so you are somewhere in Europe, ? Netherlands?
Sounds like a great pitch for a high tech start-up scam.
On a sunny day (Thu, 06 Jan 2022 12:54:46 +0000) it happened Cursitor Doom snipped-for-privacy@notformail.com wrote in snipped-for-privacy@4ax.com:
It is China news, they are of course way ahead of US and Europe.. Idea seems reasonable to me. Many years ago a German uni did something like that by modulating office lights. No idea how the mix 2 light beams, maybe some crystal.
Plus LEDs are way too slow.
Cheers
Phil Hobbs
On a sunny day (Thu, 6 Jan 2022 09:27:14 -0500) it happened Phil Hobbs snipped-for-privacy@electrooptical.net wrote in snipped-for-privacy@electrooptical.net:
Would not surprize me if there are better modulators.
>
Antennas are amazing ways to send data from place to place. I'm impressed that the tiny thing in my pocket will lock my car from 100 feet away, or that a cheap pizza-sized dish on our roof gives us
500+500 mbit internet service. No more phone booths.6G sounds great. It could replace essentially everything else... ftth, cable, TV antennas, phone lines, dishes, wifi, cat6, usb.
The problem is the wavelength, not so much the antenna. A single electromagnetic mode (one that can be interrogated with a single pair of wires) corresponds to an 'etendue of
lambda**2 / 2.
Etendue is the product of intercepted area and projected solid angle. For a dipole, the projected solid angle is
Omega' = 2 pi steradians.
So for a given intercepted area and angle, the number of modes goes up like
1/lambda ** 2.Thus if you want a linear receiver (e.g. an RF antenna and receiver), rather than not a square-law one (e.g. a photodiode) with an intercepted area larger than
Amax = lambda **2 / ( 2 pi ),
you need either to make all the phases line up (e.g. with a dish or a phased array), which reduces Omega' by narrowing the beam), or else multiple receivers.
Cheers
Phil Hobbs
My cell phone always works, even in my back pocket. Our wifi works anywhere in the house. The ultimate 9G or whatever would have a lot of small nodes out on telephone poles, with a lot of smarts. Zones would be small and overlap. Frequencies would hop as needed.
If some multi-GHz signal doesn't make it into your basement, go to Walgreens and buy a repeater for $9.95.
We're still in the dark ages with tangles of wires and dishes and people trenching sidewalks to run fiber.
In the urban areas, yes. In rural areas, not so much, as always. Too few telephone poles. Also too low a population density to make the economics work.
There will still be power and fibers going to the base stations on telephone poles. Millimeter wave beams don't go all that far, even if the buildings and trees didn't get in the way.
Joe Gwinn
I don't agree--RF works less well as you go up in frequency, even with
100% perfect parts.Semiconductors stop being semiconductors around 1 THz, because the plasma frequency is too low to allow for collective motions of electrons.
Cheers
Phil Hobbs
Short range is a virtue in a microcell system.
We don't need THz cells for Facebook and Netflix. It would be nice to have a single network in place of the mess we have now.
Mess includes the tangles of hubs and cables under my desk.
A single rural user or a small town of course needs some connection to the outside world, but it could then be 9G for local distribution.
Mass produced, the pole-top nodes would be dirt cheap... like microwave links have become.
Power for sure, but that's there. An area covered by micronodes would only need an occasional fiber or microwave connection to the world; nodes can talk to one another.
There used to be many not-interconnected telephone companies each with their own tangles of wires. A "Long Distance" call used to be a big expensive event. That's about where we are now.
The English (and Australians) write 1st April. Americans write April 1.
I think Jeff Layman is English, but he might be lazy.
On a sunny day (Thu, 6 Jan 2022 19:49:24 -0800 (PST)) it happened Anthony William Sloman snipped-for-privacy@ieee.org wrote in snipped-for-privacy@googlegroups.com:
Sure but 'een april' (1 April) is Dutch (used as reply to the joke). But OK, was just an idea.
On a sunny day (Thu, 06 Jan 2022 12:59:00 -0800) it happened John Larkin <jlarkin@highland_atwork_technology.com> wrote in snipped-for-privacy@4ax.com:
I have a 4G USB stick in a raspberry pi at home here, connected to the LAM, enough data for me for youtube videos and papers and usenet and maintain my website and email. I can take the 4G stick and put it in the laptop and have same internet anywhere. Most TV etc from a satellite dish, almost 1000 free channels. Have several phones each with prepayed cards that can do internet too. I wonder why people need terabytes of lightspeed datastreams (upload big selfies???) ? Its a hype! Recently there was a big fight about 5G interfering with aircraft altimeters, airlines threatened to cancel thousands of flights due to safety problems, now the providers will keep 5G out of the airfield areas,
No 5G in the airport on your phone :-)
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