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

Posted by EditorDavid on from the very-high-speed-internet dept.

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."

6 of 53 comments (clear)

  1. Attenuation by jargonburn · · Score: 2

    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.

  2. Not so fast - what about range? by ClickOnThis · · Score: 2

    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, 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.

    --
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  3. When terahertz is not teraHertz (THz) by DesertNomad · · Score: 2

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

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

    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...

  4. Define "channel" by Solandri · · Score: 3, Insightful

    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.)

  5. Re:Infrared? by Nkwe · · Score: 2

    ... 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.

  6. Re:I thought 1,000 Gigahertz was equal to 1 Terahe by cdwiegand · · Score: 3, Informative

    It's the band - radio operators have names for the bands, from 3m-30m, 30m-300m, etc... It's all around the number 3 for mathematical reasons relating wavelength to frequency. The band itself is often called the "terahertz" band, because it contains that frequency in the band. K0DEN

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