10 ms·

Steve Perlman's Wireless Technology Is Finally Here

123 points by amalag 13y ago

amalag 13y ago
Previous Discussion: https://news.ycombinator.com/item?id=2817730 https://news.ycombinator.com/item?id=2817730
zwieback 13y ago
Still seems hard to believe you can scale up the math and deal with intermittent changes in the RF (e.g. cars passing by) but I guess now we'll find out if it works.
- amalag 13y ago
  They mention a datacenter in the article, but seems like a perfect application for custom hardware.
  - lutusp 13y ago
    The point of the data center is to compute, on the fly, unique phase solutions for moving devices being served by multiple antennas, and to compute new solutions as the devices move. It's a huge workload, perfect for a modern, high-speed multiprocessor system to tell the cell-tower antennas which phase delay to apply to (a) each antenna, (b) each data packet, and (c) each device in a separate, changing location.
    - toomuchtodo 13y ago
      You don't need a "datacenter" per se, but you need a private control plane shared by the devices so that they can pass relevant information to each other. As long as the sites are interconnected and have some sort of addressing that is tied to their geographic location (i.e. devices know very quickly who their neighbor devices are by address), a central datacenter is not necessary. TL;DR You need a shared bus for passing geospatial data between geographically local devices.
      - lutusp 13y ago
        > You don't need a "datacenter" per se ... Perhaps, I'm just using the language from the linked article: "To work properly, a company backing the pCell technology would need to build out a large data center in addition to deploying the transmitters. It’s in the data center where servers constantly crunch away on the algorithms that form the unique wireless stream aimed at each device."
        toomuchtodo 13y ago
        I apologize if you felt like I was correcting you. The article isn't very tech heavy.
- msandford 13y ago
  It's not terribly difficult provided that you've got enough directional antennas in your base station. If you do, then every receiver is independent. In other words it could very well scale as O(n), n = the number of devices.
  - lutusp 13y ago
    > It's not terribly difficult provided that you've got enough directional antennas in your base station. This scheme doesn't rely on directional antennas, it relies on computing an optimal set of phase solutions for multiple antennas to maximize reception quality. Each antenna is an ordinary omnidirectional dipole, but several of them working together, with calculated phase delays, provide a kind of directionality if you want to think about it that way.
    - msandford 13y ago
      How do you know it doesn't rely on directional antennas in addition to the multi-phase solution? If I were trying to do something like this I would ABSOLUTELY use multiple directional antennas in each base station AND phase things appropriately. I don't mean trying to make a ball of yagis or other narrow beam antennas. But at the very least try and take advantage of splitting a base station into multiple (2, 4, 8, etc) slices. I can't see how that would hurt performance (though it would probably make things more expensive) and it would certainly make it easier to get more bandwidth. Here's an excerpt from the patent: [0120]FIG. 3 provides additional detail of one embodiment of the Base Station 200 and Client Devices 203-207 shown in FIG. 2. For the purposes of simplicity, the Base Station 300 is shown with only three antennas 305 and only three Client Devices 306-308. It will be noted, however, that the embodiments of the invention described herein may be implemented with a virtually unlimited number of antennas 305 (i.e., limited only by available space and noise) and Client Devices 306-308. Obviously I haven't studied the patent in detail but that does sound to me like there are multiple antennas per base station.
      - lutusp 13y ago
        > How do you know it doesn't rely on directional antennas in addition to the multi-phase solution? Because: 1. The article claims it can use the existing cell tower system. 2. Cell tower antennas are simple dipoles, not directional antennas. > If I were trying to do something like this I would ABSOLUTELY use multiple directional antennas in each base station AND phase things appropriately. Yes, that would improve the performance, but this would make it a hard sell to cell companies who are trying to reduce the cost of their installed equipment. Also, to use directional antennas in a high-speed dynamic network, for a given beam width N, you would need 360/N directional antennas. For a beam width of 30 degrees, you would need 12 antennas where one exists now, and you would need a way to switch between antennas on each transmitted packet to multiple served devices. That would be a nightmare. > Obviously I haven't studied the patent in detail but that does sound to me like there are multiple antennas per base station. Yes, the basic idea requires multiple antennas whose relative phase can be adjusted. But not directional antennas.
- MaysonL 13y ago
  Think phased-array radar on steroids.
eyeareque 13y ago
This is great, but I'm doubting the FCC will approve this unless he has found a way to not cause interference on the other frequencies his system uses.
- foobarqux 13y ago
  It uses LTE.
- toomuchtodo 13y ago
  If the system needs to calculate interference on the fly, it should be trivial to prevent interference to other interconnected systems.
muaddirac 13y ago
> Despite such demonstrations, Perlman has been unable to tempt venture capitalists with the technology. “They invariably bring in experts who say it doesn’t really work,” he says. “I am showing them a demo, but they remain convinced that it’s something else.” Then it's not an adequate demo?
- raverbashing 13y ago
  Maybe But they said that of the iPhone as well. There's always going to be skeptical people, even if your demo is perfect and your product is a machine that turns "crap into gold" The ratio of rejections to acceptances unfortunately is very high even for a great product (and it's possibly very low for bad products as well)
  - clhodapp 13y ago
    Are you actually claiming that subject-matter experts argued the technology in Apple's original iPhone was impossible and that the demos at its unveiling were just tricks? If so, your claim is pretty hard for me to believe, as I don't remember reading articles arguing anything like this at the time.
    - konstruktor 13y ago
      Here is one: http://www.electronista.com/articles/10/12/27/rim.thought.apple.was.lying.on.iphone.in.2007/ http://www.electronista.com/articles/10/12/27/rim.thought.ap...
    - MaysonL 13y ago
      http://www.redmondpie.com/blackberry-maker-rim-thought-apple-was-lying-about-iphone-in-2007/ http://www.redmondpie.com/blackberry-maker-rim-thought-apple...
  - wlesieutre 13y ago
    To be fair, the first iPhone demo didn't "really work". The order in which things were presented was determined by what was least likely to crash on stage. Longish article, but it's an interesting read: http://www.nytimes.com/2013/10/06/magazine/and-then-steve-said-let-there-be-an-iphone.html http://www.nytimes.com/2013/10/06/magazine/and-then-steve-sa... It was demoable in a lab setting, but you certainly couldn't have given one to a consumer and expected it to go well.
foobarqux 13y ago
Anybody familiar with wireless comms know what this actually does and what the innovation is? Is this distributed beamforming?
- cantfindmypass 13y ago
  No. The transmitters calculate signals such that constructive/destructive interference will combine to form a strong, clean signal in the precise location where the device is.
  - bdcs 13y ago
    Correct me if I'm wrong, but is this not beamforming?
    - gallamine 13y ago
      Perhaps the "trick" is a large number of antennas to produce an ultafine beam pattern?
      - lutusp 13y ago
        No, it's not the number of antennas (although there is always more than one), the method relies on the phase (or "time delay") of the signal at each antenna.
        Dylan16807 13y ago
        Why do you say no? The more antennas you have, the cleaner you can keep the beam and minimize constructive interference happening in the wrong places.
        lutusp 13y ago
        I say no because the system relies on multiple antennas, but beyond a few, the advantage evaporates while the workload increases. I wouldn't be surprised if the system limits itself to three well-placed antennas surrounding the target device, just to simplify the calculations. > The more antennas you have, the cleaner you can keep the beam and minimize constructive interference happening in the wrong places. Beyond three antennas surrounding a given device, this just isn't true -- more antennas don't produce a proportional increase in performance to compensate for the increased computation workload.
uhno 13y ago
Sounds like MegaMIMO, which allows wireless network throughput to increase linear in the number of APs added (they call this joint multiuser MIMO): http://groups.csail.mit.edu/netmit/wordpress/projects/spectrum-usage-coverage-data-rates/megamimo/ http://groups.csail.mit.edu/netmit/wordpress/projects/spectr...
deleted 13y ago
[deleted]
lutusp 13y ago
An unfortunate title -- the method doesn't rely on hardware, on "machines", it uses hardware already in place but calculates, then generates, a unique signal for each device. The method depends on the calculation, the mathematical theory, not machines. Calling this a machine is like calling the first car a horseless carriage.
- Mindless2112 13y ago
  > Calling this a machine is like calling the first car a horseless carriage. Um, they did do that, you know. I agree with your point, but the analogy is broken.
  - andrewflnr 13y ago
    Only if you assume that "horseless carriage" was a good term. I'm guessing lutusp is trying to say that was dumb, too.
  - lutusp 13y ago
    Not broken. I know that was the term used at the time, and it was a classic case of trying to describe something new in outdated terminology.
- jonahx 13y ago
  > Calling this a machine is like calling the first car a horseless carriage. So it's an excellent description which leverages an analogy everyone is currently familiar with? :P
- deleted 13y ago
  [deleted]
outside1234 13y ago
I don't get it. Wouldn't it just be easier to install more base stations with a lower transmission strength (essentially leveraging the same transmission frequency more times)?
- aidenn0 13y ago
  I can think of at least two reasons why this is superior: 1) You need to have multiple base stations installed roughly equally spaced. This seems to support heterogenous spacing of the stations 2) With lots of low-powered base-stations interference and obstructions start to become bigger issues. With many reachable antennas, a small fraction that have interference or obstructions should merely decrease SNR a bit rather than drop completely. Of course advantage #2 seems (to me) to be theoretical; I'd like to see how this performs in the real-world. The other issue I can see is moving receivers and/or moving reflectors. Imagine having this work, for example, when you are near a wind-farm, with many moving reflectors changing the apparent signal strength continuously. I know someone who worked on a similar problem in the past, and temporal coherence in real-world situations was close enough to the feasible round-trip delay to the data-center. (e.g. if you need to recalculate every 150ms and it takes 125ms round-trip to the data center, you only get 1/6 the theoretical benefit).
oneiric 13y ago
My summary, beamforming plus wider bandwidth. His white paper probably addresses the more inquisitive and technical readers' questions: http://www.rearden.com/DIDO/DIDO_White_Paper_110727.pdf http://www.rearden.com/DIDO/DIDO_White_Paper_110727.pdf 802.11ac beamforming justs boosts signal quality. It does not take advantage of more bandwidth. I don't think the math is actually that complicated to explain. I think of it as the electromagnetic equivalent of visual cryptography: http://datagenetics.com/blog/november32013/index.html http://datagenetics.com/blog/november32013/index.html An antenna not integrated into the system would see noise. The designated phone would see the exact interference pattern it needs to get the "picture."
- rasz_pl 13y ago
  Nice example with visual crypto, but does this scale? Are there algorithms able to generate arbitrary number of patterns where groups of two or more of those patterns form desired groups of signals? Basically generate 10 visual crypto pictures and be able to get different messages by combining random pairs of pictures. Because this is whats needed for this to work.
Codhisattva 13y ago
The noise is the signal. Mind. Blown.
lutusp 13y ago
I've been playing with antenna phasing and I have a preliminary result for three cellular antennas: http://i.imgur.com/tyyVh0j.png http://i.imgur.com/tyyVh0j.png The antenna locations are marked with blue dots. In this diagram the size of the high-signal-strength lobes is much larger than would be true at cellular frequencies, but it gives a sense of how this idea works. By adjusting the phase at each antenna, the lobes can be moved around to accommodate different devices within their range. As I expected, increasing the number of antennas past three doesn't really improve the outcome enough to justify the increased complexity.
- TTPrograms 13y ago
  This is called phased array, and it's been around since WWII for radar applications: https://en.wikipedia.org/wiki/Phased_array https://en.wikipedia.org/wiki/Phased_array More antennas can enable you to narrow lobes more - you may have not been phasing them properly to get that effect.
  - darkmighty 13y ago
    Yea, and MIMO is should be not only beamforming (which, best case scenario, gives you one strong channel); but it uses multipath to create essentially two channels at the same frequency.
  - lutusp 13y ago
    My sole reason for posting the example was to show how a small number of individual antennas could produce focusing lobes within a 2D space. Phased array radars use many more elements, much higher control over the wavefront, and for a different purpose. In a cellular antenna scenario, unlike phased array radar, you cannot avoid multiple lobes, but the advantage of phasing is still present. Adding antennas to the system (beyond three or four) becomes a case of diminishing returns. > More antennas can enable you to narrow lobes more - you may have not been phasing them properly to get that effect. There are paradoxical effects with more than a few antennas -- apart from the complexity issue. In some cases you will see lobes with strange shapes in locations having no benefit. With a circular array of antennas, you sometimes get concentric circles of high signal strength, not what you're after in the described system. Example: http://i.imgur.com/hK9BZnF.png http://i.imgur.com/hK9BZnF.png
owenversteeg 13y ago
I'm impressed by the Unicode spam comment on the article: мʏ вυɖɖʏ'ѕ ℮х-աιғ℮ мαĸ℮ѕ $66 нօυʀʟʏ օɴ тн℮ ʟαքтօք. ѕн℮ нαѕ в℮℮ɴ ғιʀ℮ɖ ғʀօм աօʀĸ ғօʀ 9 мօɴтнѕ вυт ʟαѕт мօɴтн н℮ʀ ƈн℮ƈĸ աαѕ $15718 ʝυѕт աօʀĸιɴɢ օɴ тн℮ ʟαքтօք ғօʀ α ғ℮ա нօυʀѕ. ɢ℮т тн℮ ғαƈтѕ SaveJury.com I wonder what spammers will come up with next.
jenwike 13y ago
Is anyone going to see the demo at Columbia University on Wednesday?

123 points by amalag 13y ago

Previous Discussion: https://news.ycombinator.com/item?id=2817730 https://news.ycombinator.com/item?id=2817730

Still seems hard to believe you can scale up the math and deal with intermittent changes in the RF (e.g. cars passing by) but I guess now we'll find out if it works.

amalag 13y ago
They mention a datacenter in the article, but seems like a perfect application for custom hardware.
- lutusp 13y ago
  The point of the data center is to compute, on the fly, unique phase solutions for moving devices being served by multiple antennas, and to compute new solutions as the devices move. It's a huge workload, perfect for a modern, high-speed multiprocessor system to tell the cell-tower antennas which phase delay to apply to (a) each antenna, (b) each data packet, and (c) each device in a separate, changing location.
  - toomuchtodo 13y ago
    You don't need a "datacenter" per se, but you need a private control plane shared by the devices so that they can pass relevant information to each other. As long as the sites are interconnected and have some sort of addressing that is tied to their geographic location (i.e. devices know very quickly who their neighbor devices are by address), a central datacenter is not necessary. TL;DR You need a shared bus for passing geospatial data between geographically local devices.
    - lutusp 13y ago
      > You don't need a "datacenter" per se ... Perhaps, I'm just using the language from the linked article: "To work properly, a company backing the pCell technology would need to build out a large data center in addition to deploying the transmitters. It’s in the data center where servers constantly crunch away on the algorithms that form the unique wireless stream aimed at each device."
      - toomuchtodo 13y ago
        I apologize if you felt like I was correcting you. The article isn't very tech heavy.
msandford 13y ago
It's not terribly difficult provided that you've got enough directional antennas in your base station. If you do, then every receiver is independent. In other words it could very well scale as O(n), n = the number of devices.
- lutusp 13y ago
  > It's not terribly difficult provided that you've got enough directional antennas in your base station. This scheme doesn't rely on directional antennas, it relies on computing an optimal set of phase solutions for multiple antennas to maximize reception quality. Each antenna is an ordinary omnidirectional dipole, but several of them working together, with calculated phase delays, provide a kind of directionality if you want to think about it that way.
  - msandford 13y ago
    How do you know it doesn't rely on directional antennas in addition to the multi-phase solution? If I were trying to do something like this I would ABSOLUTELY use multiple directional antennas in each base station AND phase things appropriately. I don't mean trying to make a ball of yagis or other narrow beam antennas. But at the very least try and take advantage of splitting a base station into multiple (2, 4, 8, etc) slices. I can't see how that would hurt performance (though it would probably make things more expensive) and it would certainly make it easier to get more bandwidth. Here's an excerpt from the patent: [0120]FIG. 3 provides additional detail of one embodiment of the Base Station 200 and Client Devices 203-207 shown in FIG. 2. For the purposes of simplicity, the Base Station 300 is shown with only three antennas 305 and only three Client Devices 306-308. It will be noted, however, that the embodiments of the invention described herein may be implemented with a virtually unlimited number of antennas 305 (i.e., limited only by available space and noise) and Client Devices 306-308. Obviously I haven't studied the patent in detail but that does sound to me like there are multiple antennas per base station.
    - lutusp 13y ago
      > How do you know it doesn't rely on directional antennas in addition to the multi-phase solution? Because: 1. The article claims it can use the existing cell tower system. 2. Cell tower antennas are simple dipoles, not directional antennas. > If I were trying to do something like this I would ABSOLUTELY use multiple directional antennas in each base station AND phase things appropriately. Yes, that would improve the performance, but this would make it a hard sell to cell companies who are trying to reduce the cost of their installed equipment. Also, to use directional antennas in a high-speed dynamic network, for a given beam width N, you would need 360/N directional antennas. For a beam width of 30 degrees, you would need 12 antennas where one exists now, and you would need a way to switch between antennas on each transmitted packet to multiple served devices. That would be a nightmare. > Obviously I haven't studied the patent in detail but that does sound to me like there are multiple antennas per base station. Yes, the basic idea requires multiple antennas whose relative phase can be adjusted. But not directional antennas.
MaysonL 13y ago
Think phased-array radar on steroids.

eyeareque 13y ago

This is great, but I'm doubting the FCC will approve this unless he has found a way to not cause interference on the other frequencies his system uses.

foobarqux 13y ago
It uses LTE.
toomuchtodo 13y ago
If the system needs to calculate interference on the fly, it should be trivial to prevent interference to other interconnected systems.

muaddirac 13y ago

> Despite such demonstrations, Perlman has been unable to tempt venture capitalists with the technology. “They invariably bring in experts who say it doesn’t really work,” he says. “I am showing them a demo, but they remain convinced that it’s something else.” Then it's not an adequate demo?

raverbashing 13y ago
Maybe But they said that of the iPhone as well. There's always going to be skeptical people, even if your demo is perfect and your product is a machine that turns "crap into gold" The ratio of rejections to acceptances unfortunately is very high even for a great product (and it's possibly very low for bad products as well)
- clhodapp 13y ago
  Are you actually claiming that subject-matter experts argued the technology in Apple's original iPhone was impossible and that the demos at its unveiling were just tricks? If so, your claim is pretty hard for me to believe, as I don't remember reading articles arguing anything like this at the time.
  - konstruktor 13y ago
    Here is one: http://www.electronista.com/articles/10/12/27/rim.thought.apple.was.lying.on.iphone.in.2007/ http://www.electronista.com/articles/10/12/27/rim.thought.ap...
  - MaysonL 13y ago
    http://www.redmondpie.com/blackberry-maker-rim-thought-apple-was-lying-about-iphone-in-2007/ http://www.redmondpie.com/blackberry-maker-rim-thought-apple...
- wlesieutre 13y ago
  To be fair, the first iPhone demo didn't "really work". The order in which things were presented was determined by what was least likely to crash on stage. Longish article, but it's an interesting read: http://www.nytimes.com/2013/10/06/magazine/and-then-steve-said-let-there-be-an-iphone.html http://www.nytimes.com/2013/10/06/magazine/and-then-steve-sa... It was demoable in a lab setting, but you certainly couldn't have given one to a consumer and expected it to go well.

foobarqux 13y ago

Anybody familiar with wireless comms know what this actually does and what the innovation is? Is this distributed beamforming?

cantfindmypass 13y ago
No. The transmitters calculate signals such that constructive/destructive interference will combine to form a strong, clean signal in the precise location where the device is.
- bdcs 13y ago
  Correct me if I'm wrong, but is this not beamforming?
  - gallamine 13y ago
    Perhaps the "trick" is a large number of antennas to produce an ultafine beam pattern?
    - lutusp 13y ago
      No, it's not the number of antennas (although there is always more than one), the method relies on the phase (or "time delay") of the signal at each antenna.
      - Dylan16807 13y ago
        Why do you say no? The more antennas you have, the cleaner you can keep the beam and minimize constructive interference happening in the wrong places.
        lutusp 13y ago
        I say no because the system relies on multiple antennas, but beyond a few, the advantage evaporates while the workload increases. I wouldn't be surprised if the system limits itself to three well-placed antennas surrounding the target device, just to simplify the calculations. > The more antennas you have, the cleaner you can keep the beam and minimize constructive interference happening in the wrong places. Beyond three antennas surrounding a given device, this just isn't true -- more antennas don't produce a proportional increase in performance to compensate for the increased computation workload.

uhno 13y ago

Sounds like MegaMIMO, which allows wireless network throughput to increase linear in the number of APs added (they call this joint multiuser MIMO): http://groups.csail.mit.edu/netmit/wordpress/projects/spectrum-usage-coverage-data-rates/megamimo/ http://groups.csail.mit.edu/netmit/wordpress/projects/spectr...

deleted 13y ago

[deleted]

lutusp 13y ago

An unfortunate title -- the method doesn't rely on hardware, on "machines", it uses hardware already in place but calculates, then generates, a unique signal for each device. The method depends on the calculation, the mathematical theory, not machines. Calling this a machine is like calling the first car a horseless carriage.

Mindless2112 13y ago
> Calling this a machine is like calling the first car a horseless carriage. Um, they did do that, you know. I agree with your point, but the analogy is broken.
- andrewflnr 13y ago
  Only if you assume that "horseless carriage" was a good term. I'm guessing lutusp is trying to say that was dumb, too.
- lutusp 13y ago
  Not broken. I know that was the term used at the time, and it was a classic case of trying to describe something new in outdated terminology.
jonahx 13y ago
> Calling this a machine is like calling the first car a horseless carriage. So it's an excellent description which leverages an analogy everyone is currently familiar with? :P
deleted 13y ago
[deleted]

outside1234 13y ago

I don't get it. Wouldn't it just be easier to install more base stations with a lower transmission strength (essentially leveraging the same transmission frequency more times)?

aidenn0 13y ago
I can think of at least two reasons why this is superior: 1) You need to have multiple base stations installed roughly equally spaced. This seems to support heterogenous spacing of the stations 2) With lots of low-powered base-stations interference and obstructions start to become bigger issues. With many reachable antennas, a small fraction that have interference or obstructions should merely decrease SNR a bit rather than drop completely. Of course advantage #2 seems (to me) to be theoretical; I'd like to see how this performs in the real-world. The other issue I can see is moving receivers and/or moving reflectors. Imagine having this work, for example, when you are near a wind-farm, with many moving reflectors changing the apparent signal strength continuously. I know someone who worked on a similar problem in the past, and temporal coherence in real-world situations was close enough to the feasible round-trip delay to the data-center. (e.g. if you need to recalculate every 150ms and it takes 125ms round-trip to the data center, you only get 1/6 the theoretical benefit).

oneiric 13y ago

My summary, beamforming plus wider bandwidth. His white paper probably addresses the more inquisitive and technical readers' questions: http://www.rearden.com/DIDO/DIDO_White_Paper_110727.pdf http://www.rearden.com/DIDO/DIDO_White_Paper_110727.pdf 802.11ac beamforming justs boosts signal quality. It does not take advantage of more bandwidth. I don't think the math is actually that complicated to explain. I think of it as the electromagnetic equivalent of visual cryptography: http://datagenetics.com/blog/november32013/index.html http://datagenetics.com/blog/november32013/index.html An antenna not integrated into the system would see noise. The designated phone would see the exact interference pattern it needs to get the "picture."

rasz_pl 13y ago
Nice example with visual crypto, but does this scale? Are there algorithms able to generate arbitrary number of patterns where groups of two or more of those patterns form desired groups of signals? Basically generate 10 visual crypto pictures and be able to get different messages by combining random pairs of pictures. Because this is whats needed for this to work.

Codhisattva 13y ago

The noise is the signal. Mind. Blown.

lutusp 13y ago

I've been playing with antenna phasing and I have a preliminary result for three cellular antennas: http://i.imgur.com/tyyVh0j.png http://i.imgur.com/tyyVh0j.png The antenna locations are marked with blue dots. In this diagram the size of the high-signal-strength lobes is much larger than would be true at cellular frequencies, but it gives a sense of how this idea works. By adjusting the phase at each antenna, the lobes can be moved around to accommodate different devices within their range. As I expected, increasing the number of antennas past three doesn't really improve the outcome enough to justify the increased complexity.

TTPrograms 13y ago
This is called phased array, and it's been around since WWII for radar applications: https://en.wikipedia.org/wiki/Phased_array https://en.wikipedia.org/wiki/Phased_array More antennas can enable you to narrow lobes more - you may have not been phasing them properly to get that effect.
- darkmighty 13y ago
  Yea, and MIMO is should be not only beamforming (which, best case scenario, gives you one strong channel); but it uses multipath to create essentially two channels at the same frequency.
- lutusp 13y ago
  My sole reason for posting the example was to show how a small number of individual antennas could produce focusing lobes within a 2D space. Phased array radars use many more elements, much higher control over the wavefront, and for a different purpose. In a cellular antenna scenario, unlike phased array radar, you cannot avoid multiple lobes, but the advantage of phasing is still present. Adding antennas to the system (beyond three or four) becomes a case of diminishing returns. > More antennas can enable you to narrow lobes more - you may have not been phasing them properly to get that effect. There are paradoxical effects with more than a few antennas -- apart from the complexity issue. In some cases you will see lobes with strange shapes in locations having no benefit. With a circular array of antennas, you sometimes get concentric circles of high signal strength, not what you're after in the described system. Example: http://i.imgur.com/hK9BZnF.png http://i.imgur.com/hK9BZnF.png

owenversteeg 13y ago

I'm impressed by the Unicode spam comment on the article: мʏ вυɖɖʏ'ѕ ℮х-աιғ℮ мαĸ℮ѕ $66 нօυʀʟʏ օɴ тн℮ ʟαքтօք. ѕн℮ нαѕ в℮℮ɴ ғιʀ℮ɖ ғʀօм աօʀĸ ғօʀ 9 мօɴтнѕ вυт ʟαѕт мօɴтн н℮ʀ ƈн℮ƈĸ աαѕ $15718 ʝυѕт աօʀĸιɴɢ օɴ тн℮ ʟαքтօք ғօʀ α ғ℮ա нօυʀѕ. ɢ℮т тн℮ ғαƈтѕ SaveJury.com I wonder what spammers will come up with next.

jenwike 13y ago

Is anyone going to see the demo at Columbia University on Wednesday?