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10Gbps Wireless Transfers
Erasei writes "NTT Science and Core Technology Laboratory Group has developed a wireless communications that is capable of transmitting data at speeds of up to 10Gbps. In order to achieve such high data transmission speeds, the system uses the as-yet-unused 120GHz frequency band. The actual bandwidth the system uses is 17GHz, and the method of modulation employed is amplitude shift keying."
So is this faster than current wired tech, or am I lagging behind?
Please correct me if I got my facts wrong.
whats the signal range?
I'm not thinking so much of a peer-to-peer or client/server setup where there's a networking handshake, but more along the lines of a broadcast data stream meant for everyone (or maybe just a few certain someones) to pick up.
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"In the laboratory, a 10m range for the system has been confirmed, but NTT is expecting to try and extend the range to 100m."
10 meters would limit its usefulness, but 100 meters would make this very useful. Hopefully, this has a useful range.
Could someone answer the question about how easily this frequency would pass through common substances, like walls?
Also, there was no mention of weather they would seek to license their technology to make this widely available or just make this a very expensive specialized niche product.
This isn't office wireless. This is a very line-of-sight system that would be used, probably, between buildings, if they get it go that far, I would imagine.
You'd never see anything like this in a home or office, as it couldn't penetrate a sheet of paper, let alone a wall of any type. I suppose it could penetrate if you put enough power into it, but then it would need enough power to melt through the wall before the communication could begin.
I'm no EE, but I studied enough analog electronics design to know that creating RF circuits at that kind of frequency is no easy feat.
Open up an 802.11 card for instance--these work at about 1/60th of that frequency--and look at the traces for an idea. It's not just what components are connected together--it's the layout of the traces that define most of the circuit. Inductors are little squiggles, a resistor is the thinning of a trace, etc., all of which is highly dependent on frequency.
In other words, these guys are pretty slick and you just have to bow to them.
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120Ghz? I can not think of an op-amp that works anywhere near the freq. Not to mention a waveguide to get your output to the antenna.
As for omnidirectional, that would lower your effective point to point power further.
At these freq's it could only be useful for point-to-point comms.
I wonder why they did not just leave it all optical.
The law is a weapon of the government, not a protection for the likes of you. Surely you understand that.
In the laboratory, a 10m range for the system has been confirmed, but NTT is expecting to try and extend the range to 100m.
Has anyone looked at the prototype they have in the picture? The transmitter and receiver are on the same table. Sure, I can understand 10gbps per sec over a few feet. They don't even know how this new technology will stand up in normal conditions. There is no way currently this will be used in mainstream. I don't know of anyone that is willing to sit within 10m of the transmitter to receive there wireless connection. I know this will be improved, but the distance will have to grow by leaps and bounds.
Yea, trasmitting 10gbps is nice, but currently what use is it if you can't go within a few feet of the transmitter?
There are many potential uses for such a high-speed wireless technology, such as for 10Gbps wireless Ethernet links or for radio links between different buildings where a high volume of data has to be sent to and fro.
Yeah, like 1.5 terabytes a day!
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let alone work in the rain, does this have a large cost advantage over free space optics?
I remember reading up on satellite signals some time ago, and how it said as the signals are such a high frequency (11-12Ghz) that they begin to show some of the properties of light. Most importantly that they cannot pass through as many objects. (Or something similar to that, I don't know much about the physics).
My question is, how much would a heavy rain/hail/snow shower affect a long range link at these high frequencies?
It sounds like they are optically processing the signal and then converting it to electrical using a special photodiode. Later through, they talk about needing a lens to focus the signal. I'm aware that some radio frequencies can be refracted by matter, but if, as others has said, this frequency range would be stopped by most matter, then what could they be making the lens out of? Or are they pulling a switcheroo and using somethig other than the 120GHz band to demo the technology?
Welcome to the net of 1000 lies. Upgrades are scheduled soon that should bring us to the 10,000 lies mark.
But on the plus side, a ULF transmitter in the Great Lakes can talk to a ship in New Zealand
Actually a dipole (half wavelength) antenna at 10 kHz (one of the frequencies they use) is 3000 kilometers!
But there is no rule that says antennas have to be any large fraction of a wavelength. A magnetic or electical antenna can be any size and have the same capture area as a dipole. This is because antennae do not have to be resonant to work - and a non-resonant antenna can be just as efficient as a resonant one, if you have a high efficiency circuit to tune out the reactance which results from the lack of resonance. This is one of the things an "antenna tuner" - familiar to ham radio operators does (the other is to transform the real portion of the impedance to a standard 50 ohms). However, it is hard to make efficient very tiny antennas. This is why these ELF systems have to use such high power.
HOWEVER, on a submarine, the resonant wavelength of a trailing wire antenna is *much* lower, because the speed of propagation in the waveguide formed by the antenna, insulation and salt water is much lower than the speed of light. Thus these antennas need only be a few hundred or thousand meters long to be reasonably efficient.
As an aside, my father invented this antenna in his PhD thesis about 50 years ago.
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They claim to use the simplest modulation scheme, that not so true: On-Off keying is the simplest (OOK modulation) it is actualy so simple that it can be regarded as either FM or AM. It is both.
Now, if they do provide 10Gbps using 17GHz, the they are getting the juice out of their bandwidth for this rather crude modulation scheme (1.7 ratio, they could get to 1.2 with stg more clever).