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Communications The Internet Japan

TeraHertz Transmitter Can Push 100Gbps+ Wireless Speeds Via a Single Channel (ispreview.co.uk) 53

Mark.JUK writes: A team of Japanese scientists working jointly for Hiroshima University and Panasonic have managed to develop a TeraHertz (THz) transmitter that is capable of transmitting digital data at a rate of 105 Gbps (gigabits per second) over a single channel using the frequency range from 290GHz to 315GHz. Previously it was only possible to achieve such speeds by harnessing multiple channels at the same time.

Professor Minoru Fujishima, Hiroshima University, said: "This year, we developed a transmitter with 10 times higher transmission power than the previous version's. This made the per-channel data rate above 100 Gbit/s at 300 GHz possible. We usually talk about wireless data rates in megabits per second or gigabits per second. But we are now approaching terabits per second using a plain simple single communication channel."

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TeraHertz Transmitter Can Push 100Gbps+ Wireless Speeds Via a Single Channel

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  • It also cooks a burrito in 2.7 seconds. :)

  • by jargonburn ( 1950578 ) on Saturday February 11, 2017 @12:52PM (#53846121)

    The biggest caveat is distance and indeed many such lab tests have measured the distance of their THz transmissions in centimetres, which is somewhat limiting. A few teams are now starting to talk in terms of metres, but right now anything up to 10 metres can be a real stretch to achieve

    As usual, distance is a huge consideration in such announcements. Not that I'm not interested; heck, 10m (~33ft) would be sufficient for most of the cases where I would personally care about high-speed wireless...if/when they can sustain such throughput at that distance.

    • The biggest caveat is distance and indeed many such lab tests have measured the distance of their THz transmissions in centimetres, which is somewhat limiting.

      A few teams are now starting to talk in terms of metres, but right now anything up to 10 metres can be a real stretch to achieve

      As usual, distance is a huge consideration in such announcements. Not that I'm not interested; heck, 10m (~33ft) would be sufficient for most of the cases where I would personally care about high-speed wireless...if/when they can sustain such throughput at that distance.

      So supposedly, if they reduce the frequency by 2, they may be able to increase the distance to kilometers.

  • TeraHertz Transmitter Can Push 100Gbps+ Wireless Speeds Via a Single Channel

    Great! Does this mean that my "My Three Sons" torrent won't be stalled at 83% for days on end anymore?

  • Yeah - now I can use my data up in less than 1/10 of a second.
  • by ClickOnThis ( 137803 ) on Saturday February 11, 2017 @01:00PM (#53846147) Journal

    From TFA:

    All of this sounds wonderful, but as usual there are some fairly sizeable catches to the promised performance improvement and as usual the press release doesn’t really touch on any of them. The biggest caveat is distance and indeed many such lab tests have measured the distance of their THz transmissions in centimetres, which is somewhat limiting.

    A few teams are now starting to talk in terms of metres, but right now anything up to 10 metres can be a real stretch to achieve and even a big improvement over that still won’t cut it for Mobile communications. The idea of using THz for Satellite links is another highly contentious one because light cloud and rain could easily cause havoc.

    Makes sense. The higher the frequency, the shorter the range due to attenuation (as another poster pointed out.) TFA talks about satellite links! Assuming they can get enough signal through water vapour, [rfcafe.com] they'd probably need some hefty directional antennas.

    This looks like a last-metre solution that could compete with Bluetooth. Anything longer than that is wishful thinking at this point.

  • Without even reading the article, a quick back-of-the-envelop calculation says that ~300 GHz corresponds to ~1 mm. wavelength (for EM radiation in vacuum or near that in air).

    That's in the far infrared range of the spectrum. Read: optical, line-of-sight surely. Well duh... optical signals can be modulated at high speed, we know that, used every day to pump data through glass fibers or change channels on your TV. Why is this news?

    • by Anonymous Coward

      That's in the far infrared range of the spectrum. Read: optical, line-of-sight surely. Well duh... optical signals can be modulated at high speed, we know that, used every day to pump data through glass fibers or change channels on your TV. Why is this news?

      For some definitions of 'far'. Not mine. The exact border of where IR starts is a bit flaky at best. Wikipedia puts it at 300GHz. Wikipedia even has a caveat The lower part of this range may also be called microwaves or terahertz waves..
      So perhaps there is something in TFA. As usual, we'd appreciate that nugget in TFS already :)
      (Here we ignore the fact that TFS already points out the nugget - this is an improvement of 10x to previous such work).

    • by Nkwe ( 604125 )

      ... Well duh... optical signals can be modulated at high speed, we know that, used every day to pump data through glass fibers or change channels on your TV. Why is this news?

      Because with 100Gb, we can change channels really fast.

  • It should be noted... that THz wireless is point-to-point. Like a laser. Even 100's GHZ are.

    It also gets absorbed by objects and the atmosphere completely different. For the same reason that 5 GHZ doesn't go through walls well.

    So this will not replace your current wifi's application.

    • I always thought that the killer application for single-channel THz radio was remote sensing. Millimeter-wave radar. For communications, it seems like using multiple channels actually provides substantial benefits. How far off base am I, anyway? :p

  • by DesertNomad ( 885798 ) on Saturday February 11, 2017 @01:37PM (#53846275)

    This article takes advantage of a definition for "terahertz band" as indicated in the paper linked.

    http://aip.scitation.org/doi/f... [scitation.org]

    The "terahertz" band is 300 GHz to 10,000 GHz, so anyone who does work at 300 GHz is working in the "terahertz" band. However, the SI terahertz unit is 1000 GHz, as another poster pointed out. So this is on the far far far low end of the terahertz band. It's like claiming you're flying when you run, because both your feet are off the ground at the same time...

    • This is a pretty commonly accepted definition of "terahertz", also called sub-mm-wave which runs from 0.3-3 THz. The atmospheric loss keeps increasing with frequency, and the expense of getting a given transmitter power also increases, so there's really no point in pushing the frequency further into the THz band at the moment.

  • Even if it is only good for a few meters if it can be made cheaply enough I can see an application for in-rack connections, replacing 100GE cables and backplanes which are a bitch to build, source, maintain and install. I wouldn't mind seeing a standard for an in-rack wireless link which provided north-south and east-west connections via small straight cavities.

    You could even have an in-chassis wireless standard that eliminates the intensive implementation of connectors and backplane. It would probably b

  • The problem is the damn things can't penetrate paper!

  • Define "channel" (Score:4, Insightful)

    by Solandri ( 704621 ) on Saturday February 11, 2017 @02:02PM (#53846377)

    transmitting digital data at a rate of 105 Gbps (gigabits per second) over a single channel using the frequency range from 290GHz to 315GHz. Previously it was only possible to achieve such speeds by harnessing multiple channels at the same time.

    Yeah, 290-315 GHz is a channel bandwidth of 25 GHz 802.11ac at 5 GHz has a channel bandwidth of up to 80 MHz (e.g channel 155 is 5735-5815 MHz).

    Basically what they're doing is equivalent to "harnessing multiple channels at the same time." They've just elected to call their use of 312.5 80MHz bands a single channel, while if 802.11ac uses more than one 80 MHz band they're saying it's using multiple channels. Kinda like saying your road can only transport so many cars per lane, while my road can transport more cars in its "single" lane (which is 300x wider than your lanes, I just haven't painted lane stripes on it).

    802.11ac can (with a single antenna) manage 433 Mbps over an 80 MHz channel, or 5.4 bps / Hz of bandwidth. 105 Gbps over 25 GHz is then 4.2 bps / Hz of bandwidth. Since there's no improvement in bps per Hz of bandwidth, basically you could get these results simply by scaling up existing technologies to higher frequencies and greater bandwidth. (Higher signal-to-noise ratio allows channel data rate to exceed frequency.)

    • No, it's not the same as using multiple channels in parallel. TFA clearly says it's a single channel.

      And yes, you could get this using "existing technologies" if you could use all the spectrum from 0 to 25GHz, for instance. The problem is that most of that spectrum is already in use.

      • It's not so much an issue that the spectrum is in use, but the ratio of the channel width to the frequency.

        Most antennas and RF circuits have an absolute maximum usable deviation of about 1.2x from their centre frequency and channelisation is usually somewhat narrower than that. That's why there are more usable wifi channels at 5GHz than at 2.45GHz (The original channel number assignments are based on 802.11 1.6MB/s rangelan systems, which didn't suffer from overlap due to their narrow bandwidth)

        This is jus

    • This is all true, but lower frequencies are divided more finely into channels because they are in more demand, and you may not be able to combine many channels together depending on demand. The mm-wave and sub-mm-wave frequencies there is much more bandwidth available, so channels can be larger. 300 GHz is not super useful right now because it is incredibly expensive to get enough transmit power to get a useful range, but that's why these technology demonstrators are done to work on technology for generatin


  • Sounds like an ideal doping model for the future. Single channel distribution margins will be AWESOME.

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