Vortex radio waves could boost wireless capacity “infinitely” After four years of incredulity and not-so-gentle mocking, Bo Thide of the Swedish Institute of Space Physics and a team in Italy have finally proven that it’s possible to simultaneously transmit multiple radio channels over exactly the same wireless frequency. In theory, according to Thide, we could potentially transmit an “infinite number” of TV, radio, WiFi, and cellular channels at the same time over the same frequency, blasting apart our highly congested wireless spectrum. Thide’s approach is rather simple. Basically, electromagnetic waves can have both spin angular and orbital angular momentum (OAM). If you picture the Earth-Sun system, spin momentum is the Earth rotating on its axis ( producing the day-night cycle), and orbital momentum is the Earth rotating around the sun (producing the seasons). In standard wireless communications — radio, TV, WiFi — we only modulate the spin angular momentum of waves. For years, Thide had theorized that orbital angular momentum could also be added to wireless signals, effectively creating a spiral signal that looks like fusilli pasta; or, in the words of Thide, a “radio vortex.” Orbital angular momentum "vortex" antennaNow, in an experiment in Venice, Thide and his Italian colleagues have transmitted two signals at the same time, on the same frequency, over a distance of 442 meters (1450ft). Pictured on the right is the antenna that the team used. No, your eyes don’ t deceive you: To create these radio vortices, all you have to do is make a cut in a standard parabolic reflector and twist it slightly. If you imagine a corkscrew of radio signals being continuously transmitted from the outside edge of the antenna, that’s effectively what’s occurring. On the receiving end, there are two “normal” TV antennae (Yagi-Uda) set apart by the same angle as the break in the transmitter. These antennae “decode” the vortex, and voila: Two radio signals transmitted over the same frequency. It is hard to put into words just how significant Thide’s discovery could be. If the vortex preserves other aspects of wireless communications, such as multiplexing, then in the short term we could be looking at a wireless spectrum that can carry 10 or 20 times as much data. In the long term, as our understanding of orbital angular momentum grows, our wireless spectrum could effectively be infinite. To be honest, this is such a huge twist for wireless communications that the full repercussions are not yet known. With radio and TV, and now cellular networks, wireless spectrum is one of humanity’s most valued resources. It is because airwaves are so clogged that companies like Verizon or Vodafone pay billions of dollars for just a few megahertz. If Thide’s discovery pans out, not only would wireless spectrum lose most of its value, but the trouble and strife surrounding LightSquared, international roaming, LTE rollout, white space wireless, and digital TV simply cease to be.
【在 X*****r 的大作中提到】 : 没看懂 : 哪儿有英文介绍
n*o
16 楼
有韭菜种子,我妈给带太多了。给个邮费给你寄吧。
Z*o
17 楼
网上都说,前面都是shi,后面是仙丹。 我已经把shi看完了,目前慢慢看出仙丹来。
【在 x***u 的大作中提到】 : 俺看到打神鞭就看不下去了
a*8
18 楼
My ways to improve my english speaking skill are: 1. Try to talk to your coworkers who are native speakers, as much as possible, listen and learn from them, 2. (This one might sound more silly) when watching TV, i will follow what the actor/actress's line and say it. Try this at home when you're alone.
【在 a***8 的大作中提到】 : My ways to improve my english speaking skill are: : 1. Try to talk to your coworkers who are native speakers, as much as possible, listen and learn : from them, : 2. (This one might sound more silly) when watching TV, i will follow what : the actor/actress's line and say it. Try this at home when you're alone.
r*n
23 楼
无线通信的究极出路 不知道和量子通信比较起来哪个比较靠谱一点
over could
【在 i*********n 的大作中提到】 : : Vortex radio waves could boost wireless capacity “infinitely” : After four years of incredulity and not-so-gentle mocking, Bo Thide of the : Swedish Institute of Space Physics and a team in Italy have finally proven : that it’s possible to simultaneously transmit multiple radio channels over : exactly the same wireless frequency. In theory, according to Thide, we could : potentially transmit an “infinite number” of TV, radio, WiFi, and : cellular channels at the same time over the same frequency, blasting apart : our highly congested wireless spectrum. : Thide’s approach is rather simple. Basically, electromagnetic waves can
L*1
24 楼
chandler,arizona是不是太热了?
Z*o
25 楼
进地仙界,当了勾陈帝君,有自己洞天。
【在 x***u 的大作中提到】 : 你看到第几章了?
r*e
26 楼
赞打客服。。。太不厚道了吧 哈哈
【在 s***a 的大作中提到】 : 口音和口语没有直接联系 : 看新闻+打客服
c*y
27 楼
关键这个研究估计已经超越经典的信息论模型了,是搞物理的人才能搞明白的了。。。
【在 r*********n 的大作中提到】 : 无线通信的究极出路 : 不知道和量子通信比较起来哪个比较靠谱一点 : : over : could
【在 a***8 的大作中提到】 : My ways to improve my english speaking skill are: : 1. Try to talk to your coworkers who are native speakers, as much as possible, listen and learn : from them, : 2. (This one might sound more silly) when watching TV, i will follow what : the actor/actress's line and say it. Try this at home when you're alone.
r*n
33 楼
many people have overly emphasized the importance of information theory. it is a theory built on upon certain assumptions and applies to certain channel models. for example the famous log-capacity-function of AWGN channels. What happened here is that the characteristic of the channel is "engineered" so that it can support much higher rate than ordinary electromagnetic wave channel, which is usually further probabilistically modeled as AWGN channel for simplicity. Although arguably, with this new vortex channel, the discrete-memoryless channel capacity MAY (provided a probabilistic abstraction is possible) still be invoked to generate the so called " capacity", yet the enabling advance here clearly lies in the process of " engineering" the new channel. It is true information theory forecasts the " ULTIMATE" limit of communication rates. However when one realizes that communication is essentially an engineering problem rather than a science, it is not difficult to understand why information theory was not the key reason that we have fast cellular communication today and will not be in the further. only my 2 cents ...
I agree, now i just repeat the line of white americans on TV, and my coworkers in my current firm are mostly white americans. I used to work with alot of african americans in my old job, my husband told me my english did sound like african americans back then. Opps.
只能LOS。。。这个问题比较大。 The Venetian innovation, which comes by way of Fabrizio Tamburini and his team of researchers, effectively takes radio waves and twists them into a vortex. As a result, you’re able to send several discrete signals over the same frequency, theoretically (though not practically) providing us with an “infinite number of channels in a given, fixed bandwidth.” Basically, the multiple signals are sent out with different degrees of spin (“orbital angular momentum states”) and the receiver can then key in on one signal or the other. The provided video demonstrates this using the standard 2.4GHz Wi-Fi band over a distance of 442 meters. You can skip ahead to 7:28 to see the actual demo itself. As one commenter points out, though, this approach “only works for line-of- sight (LOS) transmission. Once a signal bounces off a surface, the angular structure of the wave is scattered, and the polarization (or vorticity in this case) is lost.” So, is this a viable solution or is it shoddy science?
come on, what are you talking about. even the usb 2.0 port on my laptop supports 30MB/s, and the maximum rate LTE supports spotted in real life per user is around 30Mb/s.
Does this sound like one of those faster-than-speed-of-light discovery? Here is my question: Maxwell equation does not consider spin-state - that would be quantum mechanics. There are two orthogonal polarizations in free- space propagation for electromagnetic wave propagating in a fixed direction, so it is true that one can double the capacity using polarization diversity , provided one has an antenna system that can separate the two polarizations. If the technique utilizes non-electromagnetic means (i.e. quantum), that maybe a different story.
b*g
49 楼
Where is the video?
the an spin ahead
【在 c******y 的大作中提到】 : 只能LOS。。。这个问题比较大。 : The Venetian innovation, which comes by way of Fabrizio Tamburini and his : team of researchers, effectively takes radio waves and twists them into a : vortex. As a result, you’re able to send several discrete signals over the : same frequency, theoretically (though not practically) providing us with an : “infinite number of channels in a given, fixed bandwidth.” : Basically, the multiple signals are sent out with different degrees of spin : (“orbital angular momentum states”) and the receiver can then key in on : one signal or the other. The provided video demonstrates this using the : standard 2.4GHz Wi-Fi band over a distance of 442 meters. You can skip ahead
b*g
50 楼
Another question is to generate these so-called "vortices", does one need different antennas for different vortices? And on receiving end, can two Yagi antennas receive all the vortices? Assuming the energy-per-bit must still be maintained, would the power spectrum density increase to a level unsafe for humans?
【在 r*********n 的大作中提到】 : come on, what are you talking about. even the usb 2.0 port on my laptop : supports 30MB/s, and the maximum rate LTE supports spotted in real life per : user is around 30Mb/s.