German Scientists Achieve Record 100Gbps Via Wireless Data Link

Mark.JUK writes "A joint team of German scientists working at the Karlsruhe Institute of Technology (KIT) have successfully achieved a new world record for wireless data transfers. The team were able to transmit information at speeds of 100 Gigabits per second by using a radio network operating at the frequency of 237.5GHz and over a distance of 20 metres (note: a prior experiment hit 40Gbps over 1km between two skyscrapers). The radio signals were generated by a photon mixer device that uses two optical laser signals of different frequencies, which were then superimposed on a photodiode to create an electrical signal (237.5 GHz) that could be radiated via an antenna. But the team aren't happy with breaking one record and their future attempts will seek to break the 1 Terabit per second (Tbps) barrier."

Re:Thank you porn.

[nospam007]

"Porn video streaming is behind most, if not all of our technical advancements."

I see, that must be why the router said 'It hurts when IP'.

Speed?

[Arker]

So sick and tired of people equating bandwidth with speed. Is a tractor trailer faster than a Ferrari?

So what kind of ping do they get on this link?

Re:

[gothzilla]

With this technology, latency will be the least of your issues. 237.5GHz is in the upper EHF range and have a very short range because they get blocked by pretty much everything from molecules in the air, smoke, fog, rain, snow, humidity, and physical objects like walls and trees. In areas with high humidity you'd be lucky to get a signal to travel more than 1km and you still need line of sight. You won't be replacing fiber with this anytime soon.

Re:

[Trepidity]

Eh, it's a pretty colloquialism even in other parts of science to use "speed" to refer to a rate rather than only a velocity.

Re:

[wagnerrp]

Look at the speed of that cargo ship!

Re:

[LordLimecat]

Look at the velocity of that reaction!

Re:

[wagnerrp]

Depending on the nature of the reaction, it might be progressing through the medium (like a flame front), so that one could actually work.... :P

Re:

[ballpoint]

Expressing proper units and dimensions seem to be difficult for the layman, the press and even for the /. audience. mWh, MW or kW/h, it's all the same. And every time a car is moving at a high rate of speed, Newton rolls a few radians in his grave.

Re:

[operagost]

Well, the latency is ultimately going to be limited to the speed at which electromagnetic waves propagate through air, which at the refraction index of 1.0003 hardly differs from the 3x10^8 in a vacuum. Most of the latency will be introduced through the processing, although if there is much that would be trivial to address. I doubt processing power will be a difficult problem.

Re:Speed?

[Arancaytar]

Electromagnetic waves through air propagate at approximately .9997c.

Re:

[Arker]

Do you work for microsoft?

Because that fit the classic microsoft pattern - technically correct, but unresponsive/not relevant.

The time spent in the transmission of the signal is only one (probably the smallest one) of many factors that add up to produce the latency of the link.

Re:

[timeOday]

On a semi-related note, why is the latency of WiFi so sucky? I recently tried to mount an NFS home partition on a WiFi with 50 Mb tested throughput, and it was noticeably bad, to the point I broke down and ran a cable. Granted, it's a pretty sad network filesystem that performs so badly with 1-4 ms of latency. But even that is much more than wired... why? It's obviously not the flight time of radio waves over 30 feet. There shouldn't be too much re-transmission at the wireless protocol layers, for su

Re:

[timeOday]

Full disclosure, I just remembered that it was a USB WiFi adapter on the client, which doesn't help latency any. Still, I have yet to use WiFi on any other computer that had near-wired ping times either...

Re:

[LordLimecat]

IIRC, USB will add up to 10ms of latency to whatever youre using USB for.

Re:

[egcagrac0]

On a wire (or fiber), there is less contention for the available bandwidth. One device on each end of the string.

On WiFi, with everyone on channel 6, there can be interference and multiple devices having to wait their turn to talk.

Re:

[Arker]

It's a very good question. Often it has to do with obviously inferior/shoddy consumer electronics design, but even the better wireless hardware does still seem to impose significantly greater latency than an ethernet cable for the same distance, and even on the best of days.

On the worst of days, there is significant interference and that can cause a lot of retries and massive performance degradation, but that's a pile of different issues, whether sunspots or faulty wiring or the weather or whatever.

Re:

[ziggit]

If I'm not mistaken, WiFi has also traditionally been half duplex. This may have changed with some of the newer N stuff tho, I haven't really kept up. So that would definitely cause problems. That being said, if a half duplex link can kill NFS performance, I can only imagine what that would have been like in the days of thinnet.

Re:

[fatphil]

Are you trying to say that other RF comms technology is slower, but can carry more at the same time? Which wouldn't really stand up to much scrutiny at all.

A far better stupid analogy is to say that this is basically just the same as frisbeeing a dual layer DVD across a tennis court every 4 seconds.

Re:

[Dave Whiteside]

is that an African or European ....
Unladen or laden ...

Re:

[prefec2]

The correct terms are throughput vs. response time. Throughput matters for many applications including video streaming. Only interactive applications, such as tele- or videophone require low ping rates, meaning low response time.

Re:

[Arker]

"The correct terms are throughput vs. response time"

Thank you. I actually misused 'bandwidth' egregiously in my initial post and I am shocked no one has flamed me for it yet, but at least you pointed it out, if indirectly.

Throughput just doesnt equate to 'speed' even approximately though. Response time (latency) does so it's hardly unreasonable of me to point out that marketing has no idea what they are talking about. Preserving the language of Shakespeare from these cretins is in everyones interest.

"Throug

Re:

[wagnerrp]

Low latency matters considerably depending on the type of protocol you're using. If you have any kind of congestion control, which you should always have unless you're using a fixed bandwidth dedicated link from end to end, high latency will cause some serious problems as soon as you start dropping data.

Re:

[Arker]

So you are saying that bulk freight is faster than overnight air? Come now.

Obviously there can be tradeoffs between wide pipes and fast pipes for different applications. If you are trying to move a large number of sandbags across the country and speed is less important, you want bulk freight. But not because it's "faster."

Damn it.

[fuzzyfuzzyfungus]

Oh for the days when our German scientists where better than their German scientists. Truly a golden age for American Innovation.

Re:

[atomicxblue]

Even our movie stars were inventing the beginnings of wireless networks.

Re:

[weav]

You talking about Hedy Lamarr here?

Re:

[Anonymous Coward]

Who was, of course, one of our German actresses (actually, Austrian, but the countries are very closely associated...)

The Americans owe a lot to the Europeans. I seem to recall that the Brits gave us the Jet engine, Radar, Sonar and the start of the Atomic Bomb project (Tube Alloys, which changed into the Manhattan Project) during the war.

They tried to give us the Convoy System as well, but our admiral hated the Brits so much he preferred to have American ships sunk by U-Boats rather than take British advic

Re:

[fuzzyfuzzyfungus]

That was the great thing about 20th century Europe: brilliant enough to invent all kinds of neat stuff, theoretical and applied; but dumb enough to fight two nigh-apocalyptic meatgrinder wars of unprecedented brutality for reasons somewhere between 'kind of silly' and 'so baffling that historians have made entire careers out of them', thus driving much of said brilliance to the US! It'd be pretty sociopathic to suggest as a deliberate talent-recruitment strategy; but as an accidental side effect it served

Re:

[atomicxblue]

Of course I am. Hedy Lamarr was pretty cool! :D

Re:

[K. S. Kyosuke]

Of course I am. Hedy Lamarr was pretty cool! :D

Actually, she had a significant temperature gradient.

Re:

[gmhowell]

> You talking about Hedy Lamarr
It's not "Hedy", it's "Hedley".

Correct! [youtube.com]

Re:

[K. S. Kyosuke]

Oh for the days when our German scientists where better than their German scientists. Truly a golden age for American Innovation.

Don't feel bad. They have had hundreds of years of experience with German scientists, whereas the Americans with mere decades are relative newcomers in this field.

Re:

[account_deleted]

Comment removed based on user account deletion

Re:

[operagost]

Management and finance obtain the funding and drive the demand for the technology. This is what you call a "necessary evil".

Re:

[prefec2]

Tools are made by engineers. They shape the options to manipulate our environment. Our elite overlords determine how they are used. Sometimes they miss something and we get printing or the Internet out in the public ;-)

the tech is great, but

[P-niiice]

I'd hit my cap in 20 seconds

Re: 1/r^2 still true

[Anonymous Coward]

The recieved signal strength would be multiplied by the antenna gain, but the distance square loss always applies, even with a strongly directional antenna. Even if the beam width is 1 degree across, the "area" taken up by that 1 degree increases with the square of the distance.

We need some innovation

[P-niiice]

Now if only we could innovate in the usage cap area.

Re:

[qubezz]

Yep, this tech would be over Comcast's monthly usage cap in 1/50th of a second.

Re:

[SuricouRaven]

It's a good application for short-range, high-capacity wireless. The cost of laying fiber in a city is ridiculous - closing roads, digging trenches, disrupting business. Tall buildings give good line of sight. One modestly-high comm tower in the middle of the city (Something like BT Tower?) could serve all the other major buildings. Even if they don't want to depend on radio exclusively due to the risk of atmospheric disruption, it'd serve as good backup connectivity option removing the need for redundantly

Re:

[prefec2]

They most likely mean the high rise buildings in Karlsruhe, like the library. Most German skyscrapers are located in Bankfurt (alias Frankfurt). They are used as phalli for the finance industry (http://en.wikipedia.org/wiki/List_of_tallest_buildings_in_Germany).

Is there a theoretical maximum bandwith?

[deathcloset]

Slighly tangential line of thought here:

Let us imagine a cylinder of empty space with radius r = 5mm and length l = 10 meters. Allowing for any kind of medium in this space (fiber, copper, neutron-star matter, etc...), what is the maximum throughput in principle of this communication channel?

In other words, I've been wondering lately if there is an upper-bound (in principle) on bandwidth. Like how there is a speed limit for light, is there something similar for information transmission?

Re:

[wagnerrp]

You've got the Shannon limit, describing the ultimate channel capacity in terms of bandwidth and signal-to-noise ratio. You can increase your bandwidth, but your transmission medium will eventually impose attenuation limits. You can increase your power output, and thus your SNR, but you eventually reach a saturation limit from blooming, ionization, or melting of your medium. There is no theoretical limit on channel capacity, unless you want to go into information theory and figure out the maximum amount