40 GBit @ 240 GHz across 1 km LoS


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New world record in data transmission by radio

Press Release 16/05/2013

With a Langstreckendemonstrator between two skyscrapers in Karlsruhe, a
distance of over a kilometer could already be bridged. © KIT

The RF chip is only 4 x 1.5 mm2 large, since electronic components with the
frequency or wavelength scale.

© Fraunhofer IAF

Researchers at the Fraunhofer Institute for Applied Solid State Physics IAF
and the Karlsruhe Institute of Technology KIT, it is able to transmit 40 Gb /
s at 240 GHz and over a distance of one kilometer by radio. With its recent
demonstration they have achieved a new world record and establish for the
first time seamlessly with the capacity of fiber to. Such future radio links
could close gaps in the provision of broadband Internet by the wireless links
complement the network of hard to reach areas or in rural areas.

Digital, mobile and networked - the changing media usage behavior and require
progressively increasing faster data transfer rates. The expansion of the
fiber network in Germany is lagging behind European standards, such as the
statistics of the industry organization FTTH Council Europe show. To lay
fiber optic lines is expensive and in the case of natural or urban obstacles
such as rivers and transport hubs difficult. Broadband radio links can help
to overcome such critical points and so promote the expansion of network
infrastructures. In rural areas, they provide a cost effective and flexible
alternative to "Fibre To The Home 'in the expansion of broadband network dar.

In the data transmission by radio researchers have set a new world record for
the first time fully integrated electronic transmitter and receiver are
designed for a frequency of 240 GHz, with which the data transfer rates up to
40 Gbit s is / possible. This corresponds to the transfer of a full DVD in
less than a second or 2400 DSL16000 Internet connections. With a
Langstreckendemonstrator a distance of over a kilometer could already be
covered, which was built by the Karlsruhe Institute of Technology between two
skyscrapers in the "Milli Link" project. "We have managed to develop a
wireless link based on active electronic circuits similar to high data rates,
such as fiber optic systems, and thus a seamless integration of the radio
link allows" said Professor Ingmar Kallfass, the project initially at
Fraunhofer IAF in looking a shared professorship - supported by IAF and KIT -
coordinated. Kallfass since 2013 has been working at the University of
Stuttgart, where he continued to lead the project.

High frequencies allow fast data transfer

The use of the high frequency range between 200 and 280 GHz not only enables
the fast transfer of large amounts of data, but also a very compact technical
structure. Since the dimensions of electronic circuits and antennas scalable
with frequency or wavelength of the transmitter and receiver chip is 4 x 1.5
mm 2 in size. Developed at Fraunhofer IAF semiconductor technology based on
transistors with high electron mobility transistor (HEMT) makes it possible
to use the frequency range between 200 and 280 GHz with active transmitters
and receivers in the form of compact, integrated circuits. In this frequency
range, the atmosphere has low attenuation values, so that broadband radio
links are possible. "This is our spark gap compared to optical data
transmission systems easier to align and work in bad weather conditions such
as fog or rain," explains Jochen antes from the KIT.

So far, radio systems were not yet able to provide the bandwidth of an
optical fiber directly. That could change in the future, as the test shows
construction of the project. Such a powerful system possess the advantage of
the so-called bit transparency, ie, the signal could be fed directly to a
fiber without energy-intensive recoding in a radio link, transmit and
re-routed at the other end with a glass fiber. The record data from the test
set are just the beginning. "With an improvement in spectral efficiency
through the use of complex modulation formats or combination of channels, ie
multiplexing, we can achieve even higher data rates, 'said Antes is safe.
This could be the expansion of broadband network a boost. Maybe Germany will
in future no longer lies in Europe compared to the rear seats.

About the project

The project "Milli Link" is supported by the German Federal Ministry of
Education and Research within the funding program "broadband access next
generation networks" with a total of two million euros. Besides the two
research institutes Fraunhofer IAF and KIT industry partner Siemens AG,
Kathrein KG and Radiometer Physics GmbH are involved in the project. The aim
of the project is the integration of wireless links or radio links in
broadband optical communication networks in order to provide particular to
rural areas with fast Internet access. Other possible applications include
indoor wireless local area networks (WLAN), wireless personal area networks
(WPAN), and intra-machine and board-to-board communication.

Milli link Langstreckendemonstrator (print quality) [1.6095294952392578 MB
JPG] Milli link radio frequency chip (print quality) [1.7061738967895508 MB

Congrats! How does 240Ghz react to atmospheric conditions other than "clear


-----Oorspronkelijk bericht-----

By not working. At those frequencies you're talking a light moisture pocket taking the entire link down.

These links are impressive, but I think this kind of stuff was designed for outer space.

Not quite as bad:


The ~ 50 mm/h rain they seem to budget for is not yet quite an "end of the world" torrent, but it's not like you sneeze and the link goes down.
(And if you have more than 50 mm/h sustained, you've got a much, much bigger problem :slight_smile:

Grüße, Carsten

I disagree.

It's not the near field stuff that is an issue.. It's the far field stuff
further down the road that is going to murder the link.. Look at his Fig 1
and Fig 2.

Fig 1 is saying that he is getting killed at 50mm/h of rain at 60 gig and
at 175 gig. Fig 2 is saying that everything works well until you exceed
.1km - where real life kicks back in. His clear sky is normal for anything
wireless, but look at what happens at distances exceeding his comfort
zone. From .1km to 1km he's taking 30-50dB of loss on his link. I don't
know what kind of transmitter he has, but *IF* he were to encounter rain I
sure as hell hope he has a form of transmit power control. I also noticed
that they're using OOK, which is much better than FSK but runs the risk of
being clobbered by a relatively small amount of noise.

So yes, this is awesome for running huge data rates across the street.
Down the road, you may have a few bad days.

Well put; 1kM is a giant leap from .1Km, but its a far cry from rural

I wonder what the fixed mobile/metro use cases might look like; Alternate
path, aggregate short distance media backhaul...

I think I like the idea most for non-earth atmosphere use cases, space
vehicle or exploration vehicle use.

Can you blast your way through rain, snow, or hell...a sandstorm by
increasing your power?

Super high frequency stuff is already in space. Iridium uses ka for their space craft to space craft routing network. Not much attenuation in a vacuum.. :wink:

Look up vortex beams. These guys should hook up with the vortex guys. They were getting like 40bits to hertz using oam.

Nice...8x300Gbit optical beams; that's awesome.

Yeah, the orbital in addition to spin is pretty ground breaking. The pictures of the actual light are jaw dropping. And I'm not sure they actually found the limit, they just tested to whatever they had gear for.