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More Antennas, Faster Wireless
rouge86 writes "The New Scientist has a story on how researchers broke the network speed record using a wireless network and multiple antennas. They plan to use the demonstration to show how powerful multiple antennas can be. Applications include power saving on mobile phones and reducing interference."
This is just another sign that wireless is replacing wired networks around the world. I'm guessing sometime in the near future wireless will outnumber wired networks. I think that everyone can be excited about this.
Power saving is very welcome indeed. Today's 3G phones run out of battery in no-time.
For those who don't care about reading the entire article, the crux of it is:
Recombining smaller signals in real time, however, requires considerable computing power. So the Siemens team developed new computer algorithms in order to send more data using existing hardware.
In short: programmers managed to push existing hardware with a more efficient code. That's called hacking, albeit with a serious look, and I like that!
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
this is the same post, as the dec 08 slashdot post here: http://slashdot.org/article.pl?sid=04/12/08/022625 0&from=rss/
OFDM has been around for a while OFDM History
It's nice to see more practical uses of it in wireless standards like WiFi IEEE 802.11a, 802.11g and in WiMax IEEE 802.16a.
All this adds up to the death of the control by telco's in the last 100 yards of net connectivity. Go OFDM!!
Quidquid latine dictum sit altum viditur
Since the improvement was mainly a hack on the processing.. I'd guess that they went from some sort of fourier transform to wavelets.. wavelets have linear computational complexity (awesome) and don't have the interference problems that older signal processing algorithms have.
Is anyone else making the comparison between "more antennas=better" and the mach 3 razor "more blades=better"?
...now I have to buy a new phone again.
How am I supposed to fit a pithy, relevant quote into 120 characters?
And increasing it for the neighbour, unless he also has multiple antennas.
Wich gets us back to the start, only with even more interference...
Hivemind harvest in progress..
Porcupines discovered this way before these researchers did.
Banu
Its not the size of your antenna, its the number you have??
This comment does not represent the views or opinions of the user.
Of course, this means more fodder for us wardrivers -- more antennas mean more UINs to map!
Zhrodague.net - I do projects and stuff too.
It's mathematics and a solid understanding of signal propagation that made the antennas possible.
It's mathematics and tuning of the algorithms used to work through that mathematics that made the DSP firmware possible. You have to thoroughly understand the math behind the DSP stuff to optimize it right.
Just because there's code involved, doesn't mean that there were just code-monkeys doing the work.
I am not merely a "consumer" or a "taxpayer". I am a Citizen of the State of Texas
OFDM has nothing to do with mulitple antenae. You can send OFDM signals across a channel with a single RX and TX antena. OFDM is simply a convinient way to turn a freq-selective fading channel into multiple, independent flat fading channels by interpreting the data as the IFFT of the TX signal. Spreading the data out over frequency can be used to get good diversity and thus avoid bad fades.
Using multiple antenae is also a good way to get diversity in a way that complements OFDM (spatial vs. freqency). More diversity in an RF channel is almost always good. The exception is when it forces you to spread your energy over multiple sources too mutch. However multiple RX antena don't increase energy use, instead they just absorb more energy, and in a manner that is better than a single antena with twice the gain. This is because while one antena may be in a bad fade (a destructive multipath null), chances are much lower that both will be in a bad fade.
Multiple TX antenae can be used too, but the implementation (and decoding) gets mutch more complex as the article suggests: you need lots of computing power to grab the bits out of multiple simultaneous (but cooperating) TX sources. You also spread your energy with multiple TX antenae, which lowers overall SNR.
"You saved 1968." - Ms. Valerie Pringle to the crew of Apollo 8
Ok, after the (mostly) needless citing is done, I find it nave to have faith in science. Then again, it seems to be the most powerful metatool we have found. I call it a metatool for it allows you to both create another tools and to refine itself into being an even better tool. Perhaps Chemistry won't solve all mankind's problems, on its own, or perhaps it will, or perhaps solving that will require several sciences combined. I can't see that far. Science may not be the answer to all (because we know the answer is 42 -see Douglas Addams-), but it's the best approximation we have found yet.
Are you sure there couldn't be a mesh? With a good enough antenna, all you need is almost-line-of-sight (diffraction can get you around a couple of hills before you lose all your signal). K5 is just talking about a new wireless standard that lets you signal 50km. Surely a mesh could form if the cells were that big?
I am trolling
I learnt a couple of years ago in Telecommunications class about the benefit of more than one antenna for wireless communications. Maybe the big deal is that products are starting to come out to the market. The technology however, is nothing new.
I see nothing new in this principle - anyone knows that more aerials are better - in fact, if you increase the number of aerials so that their combined length (l) matches the exact distance between the sender and the receiver (ie: l = d), AND then you place each aerial in and end-to-end configuration so that electrons can flow in an unbroken path from transmitter to receiver then you have a very efficient data transmission medium - heck, the principle even works with optical fibre and photons too.
AT&ROFLMAO
This is where VPNs and encryption come in.
And the number of places deploying VPN's and encryption over their wireless networks are... ? Have you ever walked around a city with a wireless device?
still have the issue of authentication
There used to be the issue of access before you had to deal with the weak authentication thats set up in most places. Admins are bending over backwards to open holes as they deploy wireless networks.
"I use a Mac because I'm just better than you are."
I would think that a mean network would be the 802.11b network running 11MBits, not 50. Are there really that many 802.11g networks out there, pushing the average up to 50, or is this reporter just clueless because their office runs around 50? I used to travel quite a bit, and what networks I did run into at coffee shops and airports were 11 Mbit. Do others have a different view than this?
Great ideas often receive violent opposition from mediocre minds. - Albert Einstein
so now i need six more pringles cans for my end alone?
...I got nothing.
So we replace wires with wireless but double up on the amount of terminated wires (ie antenna's), cute. Aint you all glad somebody never put a RS232 on the back of a microwave oven, as I'm sure somebody would convert it into a crude basestation :)
So we get rid of all the wiring inside and terminated it on the outside a few doxen times instead and coat in plastic, and people get upset about mobile phone masts, boy are they in for a new shock soon when Joe Smith turns his house into a hedgehog array.
we all turn into Radioactive man. Or should I say... cancer man
- There's no place like 127.0.0.1
Exactly! Except that nowadays you don't have to have your wife or your kid up on the roof holding the antenna in the sweet spot so you can watch the game with your friends ... software does it automatically. Once again advanced technology comes in to improve the quality of our lives.
The higher the technology, the sharper that two-edged sword.
...for standardization as 802.11n
Proposals were submitted back in August for 802.11n, and all proposals still in the running use MIMO+OFDM (the technique described here). Hardware supporting various prototypes is already around in a usable form.
It seems unlikely that 3x4 MIMO will be around in the first wave, due to cost constraints - 2x3 (2 tx, 3 rx) is the most likely initial configuration.
This reeks of channel-bonding to me. How (if it is) is this different?
We can't disparage the telco's control too much. Though tyranical at times, there is a financial backbone that we don't want to break. We're pushing for a Marxian revolt on the telco's to go Robin Hood on internet bandwidth, but we're griping at an alarming rate about IT jobs going overseas and jobs being lost in the IT sector. We want the technology, but we don't want to pay for it...people want what you make at your job for free too.
This is the same entitlement scenario that was looked at with MP3s and the iPod years back. Internet bandwidth was funded by someone. Music was created by someone. We think we're entitled to anything that can possibly be accessed for free just on the principle of the matter. To conceptualize - on the day you can give away your own job services for free, start demanding free internet and music.
Hmm.. science vs. religion again.
Suppose someone is sick with a disease. The religionist's approach is to pray over the person, or cast some spells, or some such nonsense. Occassionally, the person will get better, and the religionist will say it's because his god did it. Most of the time, the person dies, and the religionist says the god willed it.
Then a scientist comes around. He determines the disease is caused by a bacteria. He does experiments, and figures out how to kill the bacteria using penicillin. He gives these to the disease sufferers, and they all get better. Then, the scientist goes further, and isolates some of these bacteria, and shows what they look like under a microscope. He makes a video from the microscope showing how the bacteria these people were infected with dies when it's introduced to penicillin.
Where's the need for "faith"? And where's the need for religion? I don't need faith when I flush my toilet that it'll work properly. I don't say prayers when it stops up. I understand how a toilet works, and when it doesn't, I fix it, usually with a new flapper valve or with a plunger.
Why is it that simple-minded people always want to appeal to "faith" instead of taking the time to learn how things really work?
Now given to options pay nothing and get say 100th the bandwith or pay 50$ an month and get full bandwith most people are going to opt for spending cash
NetZero: $10/mo for 48 kbps. Comcast: $46/mo for 3000 kbps. Trust me, people will put up with 1/60 the speed to save cash. And are you sure it'll be 1/100 the bandwidth, or just 100 times the latency?
So unless the mesh networks start having servaces that the ISP wish to connect to your not going to see mesh networks making the internet free.
Some universities will have both Internet and Meshnet. Watch students set up gateways as a class project.
Why is it that simple-minded people always want to appeal to "faith" instead of taking the time to learn how things really work?
I was going to look into that once, but I decided it was easier to just believe that they are all simple-minded.