[HN Gopher] 240-Gbit/s sub-THz wireless communications using ult...
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240-Gbit/s sub-THz wireless communications using ultra-low phase
noise receiver
Author : ulrischa
Score : 65 points
Date : 2024-02-01 19:07 UTC (3 hours ago)
(HTM) web link (www.jstage.jst.go.jp)
(TXT) w3m dump (www.jstage.jst.go.jp)
| kennethrc wrote:
| Apropos of absolutely nothing, but IIRC a "Star Trek" movie where
| a screenshot of one of the displays on some ship or another had
| the Shields Frequency up which allowed the enemy to match it and
| disable it, and back in the 80s(?) when this came out I remember
| thinking "237GHz" (or something like that) was an insanely high
| frequency and doubted it could ever be reached with any degree of
| stability. Physics: HMB
| moreati wrote:
| I thought it might be Generations, but that was 257.4 MHz
| https://www.youtube.com/watch?v=6A9IZHWz45Q&t=20s
| kennethrc wrote:
| That's the scene. Says it's from 1994.
|
| After that, I'm sure the Owner's Manual that comes with your
| new Enterprise-class Starship now has a "DO NOT DISPLAY YOUR
| SHIELD FREQUENCY" in the "Warnings" section
| Cthulhu_ wrote:
| I mean I get that series like Star Trek rely on
| technobabble and suspension of disbelief, but surely an
| enemy can just... detect the frequency, or rapidly adjust
| their own like tuning in until it matches?
| mmh0000 wrote:
| That would work, but modern starships use a rotating
| phased tachyon field to prevent that.
| AlexAndScripts wrote:
| With an inversed polarity!
| mmh0000 wrote:
| To be fair, we don't know if Starfleet ever figured out how
| the Klingons bypassed the shield. Nor do we know if they
| ever discovered someone installed a rootkit on Geordie's
| visor.
|
| Also, given Starfleet's continued examples of not learning
| their lessons from previous encounters, I suspect all ships
| still display the shield frequency in big, bold font.
| Possibly even visible from the viewscreen of the bridge on
| one of the rear consoles.
| Palomides wrote:
| I'm curious about the use cases for 275 ghz wireless
| communication, are microwave links still common? it's almost far
| infrared
| woah wrote:
| Microwave links are very common
| wrs wrote:
| WiFi is microwaves.
| ianburrell wrote:
| The same use as optical wireless like LiFi. Higher speed over
| short distances.
|
| Optical has the advantage to bouncing off walls, but EHF may
| have bandwidth advantages.
|
| This wouldn't be useful for microwave links since it is
| absorbed by the atmosphere and has short range.
|
| 275 GHz is one the edge of EHF. Terahertz is 300 GHz to 3 THz.
| Above that is infrared.
| _fizz_buzz_ wrote:
| By far most communication is in the microwave bands, such as
| WiFi, cell phones, Bluetooth
| Palomides wrote:
| sure, but wifi doesn't go over 6ghz for plenty of reasons
|
| edit: forgot about 60ghz wifi
| westbywest wrote:
| 60GHz wifi products are pretty common now. With the notable
| quirk of having difficulty passing through paper.
| mometsi wrote:
| Paranoiacs will be finally be able to wear regular hats!
| JohnnyD10 wrote:
| When incorporated into Wifi 18 in the year 2046, it will prove to
| realistically get around 500 MB/s, and have a hard time getting
| through most walls.
| I_Am_Nous wrote:
| They are only transmitting 30 mm, when they moved to
| transmitting 20 meters it had to drop from 64QAM to 32QAM and
| lost some throughput. It's also laser generated so I don't
| believe it's omnidirectional, just point to point.
| connicpu wrote:
| Sounds more practical for satellite-to-satellite
| communication than for consumer devices then if it's being
| sent with lasers
| Cthulhu_ wrote:
| Might work well in open office and large public spaces
| though, there's quite a lot of things in between consumer
| and space.
| NavinF wrote:
| Jokes aside, I get a consistent 1600mbps over wifi 6E which is
| good enough for me.
|
| Of course you need an AP in every room to get consistent
| performance, but wifi has always been like that. And unless
| your applications use forward error correction wifi will always
| have latency spikes from L2 retransmission if there's even one
| wall between the AP and device
| toastedwedge wrote:
| If I may ask, what is your hardware setup like if you're
| achieving consistent 1.6Gbps? Is that a reproducible, every
| day speed? Is that only for LAN or both LAN+WAN?
| glitchc wrote:
| An AP in every room, incorporated into the light fixture.
| Sounds like a business model just waiting for some funding.
| notso411 wrote:
| Already exists
| glitchc wrote:
| Could you share a link?
| NavinF wrote:
| Why incorporated into the light fixture?
|
| I paid ~$280 for each U6 Enterprise and that's the only
| thing that limits how many I have. I'm sure it's the same
| for anyone that cares about wifi performance. How much of a
| premium would you pay for better aesthetics?
| ijhuygft776 wrote:
| > wifi has always been like that
|
| not for me
| matsz wrote:
| If you live in a small/medium apartment then 6E is quite
| good. I've been using one of those "enterprise" tri-band APs
| for around a year and my experience has been also amazing,
| with just one AP in the entire flat.
|
| Enabling all bands should allow your device to just drop to
| 5GHz/2.4GHz when needed. This has been seamless for me.
| Yizahi wrote:
| Depends on the wall construction. Bricks or some AAC will
| be fine. Steel reinforced concrete panels - and you might
| as well call it Faraday cage.
| genpfault wrote:
| > have a hard time getting through most walls.
|
| Dial up the TX power.
| xattt wrote:
| > ... have a hard time getting through most walls.
|
| Thankfully, the Class Wars of 2037 has caused most of society
| to move into tents, so signal penetration through walls was no
| longer an issue.
| zwieback wrote:
| Skip ads in 5,4,3,2,1,...
| aDfbrtVt wrote:
| Something not totally clear from the title, but it seems the
| claimed rate was actually achieve with a transmitter structure
| similar to what you would find in coherent optics (see figure 4).
| Instead of coupling to fiber, they couple to a high speed
| photodiode that radiates at the ~140GHz laser wavelength.
|
| EDIT: Noticed that after a closer reading of the paper, the real
| goal was to assess the LO phase noise improvement when moving
| from a RF synthesizer to a SBS laser and PD based LO.
| genman wrote:
| Does 20-m here stand for 20 meters or something else?
|
| "We also demonstrate successful 20-m transmission at a data rate
| of over-200 Gbit/s data rate."
| I_Am_Nous wrote:
| Yes, it's referring to transmitting with 20 meters between
| transmitter/receiver. Their highest speed transfer was done at
| 30 centimeters between transmitter/receiver.
| Animats wrote:
| 275 GHz. Getting close to terahertz. Nice.
| londons_explore wrote:
| They make a big point of using HD-FEC rather than SD-FEC.
|
| To me, that makes no sense - the extra power usage of SD-FEC can
| be tiny, even at high data rates. The FEC problem can be
| parallelized (if the protocol is designed for this) so it doesn't
| need to run at line rate too.
|
| (SD-FEC lets you get substantially more data throughput in a
| given channel).
| lacoolj wrote:
| Would like to see the environmental impact and public health
| studies done with this
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(page generated 2024-02-01 23:00 UTC)