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Wireless Networking

New 'pCell' Technology Could Bring Next Generation Speeds To 4G Networks 120

Posted by Unknown Lamer
from the spherical-harmonics dept.
An anonymous reader writes in about a possible game changer in wireless technology that embraces interference with great results: "It's one of those elegant inventions that only surface maybe once a decade. If it works at scale, according to IEEE Spectrum, it could 'radically change the way wireless networks operate, essentially replacing today's congested cellular systems with an entirely new architecture that combines signals from multiple distributed antennas to create a tiny pocket of reception around every wireless device.' This scheme could allow each device to use the full bandwidth of spectrum available to the network, which would 'eliminate network congestion and provide faster, more reliable data connections.' And the best part? It's compatible with 4G LTE phones, which means it could be deployed today." The idea is that an array of dumb antennas are deployed and a very powerful cluster computes signals that are sent from all of them which then appear to be a single coherent signal to only a single device. There's a short paper on the Distributed In Distributed Out technique, but it is a bit light on the mathematical details.
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New 'pCell' Technology Could Bring Next Generation Speeds To 4G Networks

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  • by rossdee (243626) on Wednesday February 19, 2014 @02:23PM (#46288205)

    So like Warp 9.5 then?

    • Logged in just in case I had mod points, but alas I have none. I tried.
    • This space ship goes to 11, man!

    • As I read this, DIDO is exactly "steerable null" with the antennas spread out.

      Of course the antennas are spread out VERY FAR APART, as in to multiple sites using a central computation of the I/Q signal and synchronizing separate local oscillators at the remote sites. This results in "bubbles around", rather than "beams at", those cellpphones that are in among the antennas.

      • Sure, but will they be able to construct these "bubbles of bars" for thousands of users around 2-5 antennae [ie, support the same number of users for the same antennae density]. And track each of antennae in those phones to the nearest cm [1/2 inch in American] as they move in realtime, and recalculate how to move the '5 bars bubble' to be where the cell phones antennae is, even as the phone moves in an unpredictable fashion.

        And this doesn't improve the signal from the phone to the tower.

        Theoretically, thi

    • by Anonymous Coward

      So like Warp 9.5 then?

      No, like actual 4G speeds!

  • by Anonymous Coward
    The big wireless operators haven't even finished rolling out (let alone paying for) their 4G rollout, and somebody thinks they're going to scrap it all and spend billions more rolling out new technology? O-K....
    • by pepty (1976012) on Wednesday February 19, 2014 @02:44PM (#46288443)

      The operator would then need to install radio antennas where its customers are located, such as in homes, businesses, and city streets. Although these access points might look like small cells (Artemis’s, pictured below, are about the size of a hat box), they’re unlike ordinary base stations. “They’re dumb devices,” Perlman says, serving merely as waypoints for relaying and deciphering signals. Each one could be placed anywhere that’s convenient and would link back to the data center through a fiber or wireless line-of-site Internet connection.

      Doesn't sound expensive at all - for the operator. They'll just install pCell hardware for the customers that want it in their location at 200% of cost.

    • by Anonymous Coward

      Actually what's cool about this approach is that the startup company behind it has made the new technology compatible with existing LTE (4G) networks. So operators wouldn't need to swap out the old for the new all at once, as they did to make the leap from 3G to 4G. Rather, they could just use pCell where they need to, such as in busy urban centers, and LTE users wouldn't know the difference (except for the suddenly good reception).

      • by rudy_wayne (414635) on Wednesday February 19, 2014 @03:02PM (#46288645)

        Actually what's cool about this approach is that the startup company behind it has made the new technology compatible with existing LTE (4G) networks. So operators wouldn't need to swap out the old for the new all at once, as they did to make the leap from 3G to 4G. Rather, they could just use pCell where they need to, such as in busy urban centers, and LTE users wouldn't know the difference (except for the suddenly good reception).

        According to TFA (which of course no one read):

        "“Demand for spectrum has outpaced our ability to innovate,” says Perlman. The reason isn’t for a lack of ideas. The wireless industry is pursuing plenty of them, including small cells, millimeter-wave spectrum, fancy interference coordination, and multiple antenna schemes such as MIMO. But Perlman thinks many of these fixes are just clever kludges for an outdated system. The real bottleneck, he argues, is the fundamental design of the cellular network. “There is no solution if you stick with cells,” he says.

        Even though it is technically compatible with 4G you still have to deploy millions of new antennas. He may have invented the greatest wireless technology ever, but it's dead on arrival due to cost.

        • by Anonymous Coward

          Actually, you wouldn't have to deploy millions. You could deploy a couple doze in a ball park, for example, and get a good boost in capacity. And operators are already investing in infrastructure like this, such as small cells to try to cover places like ball parks. Infrastructure-wise, pCell wouldn't present any more challenges than small cells. In fact, they might even be a bit cheaper and simpler because they can be installed anywhere in a given area. You don't want one on your roof, but maybe your neigh

        • Even though it is technically compatible with 4G you still have to deploy millions of new antennas. He may have invented the greatest wireless technology ever, but it's dead on arrival due to cost.

          Actually it may be cheaper than buying more spectrum and putting in more equipment at the cell sites, since it doen't involve buying more spectrum.

          It DOES involve putting in more cells. But far fewer than you'd need to put in to subdivide the cells, in the normal cellular paradigm, to get the same amount of bandw

          • (I'm not used to the tuchpad on my new laptop and seem to have actidentally posted mid-edit. Reposting the full version.)

            Even though it is technically compatible with 4G you still have to deploy millions of new antennas. He may have invented the greatest wireless technology ever, but it's dead on arrival due to cost.

            Actually it may be cheaper than buying more spectrum and putting in more equipment at the cell sites, since it doen't involve buying more spectrum.

            It DOES involve putting in more cells. But fa

            • "It DOES involve putting in more cells. But far fewer than you'd need to put in to subdivide the cells, in the normal cellular paradigm, to get the same amount of bandwidth reuse multiplication."

              From the descriptions, it sounds like it's basically phased-array technology, which has been in use in radar systems for decades. Of course this is a vastly different application and involves active feedback, so while the physics might be the same the rest isn't.

              This was actually done for public wi-fi many years ago. It worked, but it turned out the cost was not much if at all lower than just coverage with simpler hotspots. But again: this is a different application and these are different circumstances.

        • Much like 4G never took off because not only did it require the deployment of millions of new antennas but also hundreds of millions of new phones.

          Wait, what? 4G wasn't dead on arrival due to cost?

          The moral of today's story is that new infrastructure is periodically rolled out, and the cost of such rollouts doesn't prevent them from occurring. Additionally, there are considerably fewer cell towers than there are cell phones.
        • What does one antenna cost?

          Can I put one on the pole outside my bedroom window?

          If I could get reliable cell coverage in my home, I'd pay $200-300 for that.

          • by schnell (163007)

            If I could get reliable cell coverage in my home, I'd pay $200-300 for that

            You can already do that today, that's what femtocells are all about. AT&T version here [att.com], Verizon version here [verizonwireless.com]. I'm sure most other carriers have similar options... no fancy new technologies required.

          • by cduffy (652)

            If I could get reliable cell coverage in my home, I'd pay $200-300 for that.

            Switch to Republic [republicwireless.com], and your voice, SMS and MMS all run over your WiFi, and hand off to Sprint's cell network when out-of-range.

            Which gives you reliable coverage in your home, and a deep discount from a typical carrier's monthly rates.

            -- Satisfied customer. (Well, moderately satisfied -- Sprint's 4G coverage in Austin was iffy until they got a bunch of tower repairs done; that they let it go for such a long time didn't speak well).

            • I have T-Mobile with WiFi calling, it's a good thing, but not as "rock solid" as you might expect it to be.

              • by cduffy (652)

                I switched over from T-Mo. Republic's implementation is considerably better, particularly the handoff support.

                • Can they do it (WiFi calling) on a Nexus 5?

                  • by cduffy (652)

                    No; they support only their own hardware (Moto X w/ custom firmware).

                    On the other hand, it's a no-contract subsidized current-gen phone, and it's the first device I've had where manufacturer firmware is actually an improvement on AOSP.

                    • We've got those "no-contract" phones from T-Mo, and what I'm realizing about them is that, while there's no service contract, I've invested close to $2000 in 3 phones that aren't actually very portable to other carriers.

                    • by cduffy (652)

                      That's why "subsidized" is a relevant thing. :)

  • What about recieve? (Score:5, Interesting)

    by ThatAblaze (1723456) on Wednesday February 19, 2014 @02:29PM (#46288275)

    Being able to transmit more strongly is all well and good, but the phone can only send using so much juice. If you turn up the power of the phone too much it will just get in the way of other phones' transmission like they do now.

    Still, half of a solution is better than nothing, I suppose.

    • I doubt it, they'd calculate latency from tower to tower and analyze the data on the fly to pull out more accurate results. (that's how I read it anyway)

    • by Immerman (2627577)

      I suspect that the technique is reversible - your phone signal will interfere with all the others, but by analyzing the composite signals received by all the antennas in range the signals from individual phones can be reconstructed.

      • Precisely. The equivalent computation is done in the receive pipe, so the base station system "hears" from each bubble separately, as well as "speaking" separately to each.

        In fact it has to be done this way, or you'd only get the bandwidth multiplication in the outbound direction and the inbound direction would be sharing the bandwdith. (Fortunately the transmit and receive pathways are exactly duals of each other.)

        • by Immerman (2627577)

          In fairness, even if they could only manage phased signal transmission and had to rely on old fashioned reception, that would still be a pretty huge benefit - video-chat aside download speeds are far more important than upload speeds for most people.

          Did seem logical it would work both ways though.

          • I'm seeing no mention of latency here. Running expensive computations to reconstruct the signal is going to add a considerable amount latency, which more or less eliminates video-chat applications. And this is a computation which gets more complex the mode devices you have in an area too.

            • I'm seeing no mention of latency here. Running expensive computations to reconstuct the signal is going to add a considerable amount latency, which more or less eliminates video-chat applications.

              Nope. It's done in a DSP, just like the computations that form the modulation/demodulation in the first place. It's blazingly fast (it HAS to be because you do it for every sample of the signal.)

              The computation for DIDO (- steerable null) is a matrix multiply. Two additions + 2 adds times the product of the num

              • The computation for DIDO (- steerable null) is a matrix multiply. Two additions + 2 adds times the product of the number of base station antennas and the number of active remotes.

                Sorry, typo: Two multiplies and two adds. Ammortized per channel it's only an extra (multiply and add) * 2 * number of antennas for each I + Q sample of the generated waveform.

    • Most phone use is download. Unless you're trying to stream live video up from your phone (or run a freaking server, please) you don't really need it. Also it's just one broadcast point -- this seems to need multiple to craft some kind of partial waves that stack up only in a very limited region of your actual phone location, with all that partial crap just cresting through each other for everyone else. Think a whisper gallery where the walls are computer-driven antennae controlling pseudo-reflections.

      • Unless you're trying to stream live video up from your phone [...] you don't really need it.

        What do you think Skype and FaceTime are?

      • Most phone use is download.

        AFAIK, most "download" protocols are bidirectional - there's a confirmation that each block was properly received. (TCP vs UDP)

        The portable device may not need to transmit much, but there's likely a string of "Yup, Checksum OK"'s getting transmitted, even when "just" streaming a video.

    • by Solandri (704621)
      It can be used both ways. What they're describing is basically tomography [wikipedia.org]. By analyzing the signal recorded from different locations, you can construct a 2D or 3D representation of signal strength, thus allowing you to pin down a specific phone's transmissions based on location (rather than frequency or code or time - what's used for OFDMA, CDMA, and TDMA respectively). The reverse process would involve modulating the transmission strength and phase from multiple towers in a synchronized fashion so that
  • Phased array. (Score:5, Interesting)

    by harrkev (623093) <<kfmsd> <at> <harrelsonfamily.org>> on Wednesday February 19, 2014 @02:29PM (#46288279) Homepage

    It sounds like a logical extension of phased-array technology. Or, sort of how they do radiation cancer treatment with dozens of weak beams converging on one spot.

    However, in order to get this to work well, you need the transmitted signal to be phased-aligned to within an appreciable fraction of a wavelength. Since we are around a gigahertz, that means that the phase of the carrier should be accurate to within a couple hundred picoseconds, max. How you maintain this accuracy over multiple cell sites confuses me. Of course, this is all a wild-ass guess on how the technology works.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      And, even if it only appears as a proper signal at one point, it's going to raise the noise floor for everyone.

      • Re:Phased array. (Score:5, Informative)

        by harrkev (623093) <<kfmsd> <at> <harrelsonfamily.org>> on Wednesday February 19, 2014 @02:55PM (#46288563) Homepage

        True about the noise floor.. However, if this works as advertised, the net gain in one spot should overcome the generalized increase in the noise. For example, a 10 dB gain in local signal would be well worth even a 6 dB gain in overall noise.

        • But doesn't recreating a waveform by summing several other waveforms require that those components be of significantly higher frequency? Basic Taylor series stuff? E.g. recreating a 1 GHz carrier at the receiver from 10 random-distance sources would require each of those sources to be in the order of 10 - 100 GHz, especially if those transmitted waveforms are further constrained to be simultaneously delivering signals to other receivers.

          • by harrkev (623093)

            No. Not at all. You are just summing 1 GHz. Simple (or not-so-simple) constructive and destructive interference...

      • by Chalnoth (1334923)

        This isn't necessary at all. It's entirely possible for there to only be an appreciable amount of EM radiation at the desired destination. So you can actually lower the noise floor for everybody else versus today's systems. In fact, because the destination signals are spatially-localized, your only limitation on how many devices you can put on the same network is the size of the localized waveform.

        The primary concern I have is how they're going to accurately determine the position, and how they're going

    • by strstr (539330)

      Directed-energy is another thing. Say the antennas become focused, directing energy right to the devices, and separating the signal from each device by creating a higher resolution sensor for imaging the surrounding landscape..

      Ideally the phones would have a similar mechanism but current 4G LTE phones do not. they are omnidirectional and broadcast noise in all directions, even if the antenna system is at a specific location.

      the current system is a waste of resources and terrible design, really antiquated ..

      • Ideally the phones would have a similar mechanism but current 4G LTE phones do not. they are omnidirectional and broadcast noise in all directions, even if the antenna system is at a specific location.

        That doesn't matter. You just do the equivalent computation on the returned signal. You "listen" separately to the individual bubbles, just as you send separately to them.

        So you only need to do it at one end - the one where coordinating and combining the signals is practical.

    • Good point. Time synchronization would be something of a hurdle. However it seems like a solve-able problem since we ARE talking about a device that can send and receive signals wirelessly in order to synchronize. Guess and check works pretty well for this, i.e. packet 1: "I think you are receiving this at 1:17:36.455667" packet 2 "it was 0.0003 seconds fast."

    • by Immerman (2627577)

      Yes it does.

      Well, if you've got sufficient precision then continuous synchronization can probably be done using known signals received by all antennas - a few calibration antennas perhaps, or listening in on GPS signals. Of course that assumes that resynchronization is necessary, and it may well not be: The signal delay between headquarters and the various antennas can be constant if so designed, and the antennas can be made sufficiently non-mobile without too much trouble, though those tall cell towers t

    • It sounds like a logical extension of phased-array technology. Or, sort of how they do radiation cancer treatment with dozens of weak beams converging on one spot.

      The former. Phased array is coherent (phase between sources is controlled and signals can cancel). Reverse-tomography radiation treatment is incoherent (phase is uncontrolled and energy only adds - but you make it strong in one place and as weak as practical elsewhere, or especially weak at other particularly radiation-sensitive sites.)

      (I'd love

      • by harrkev (623093)

        It is sort of a combination of the two... Phased array usually has one source (well, dozens of sources, but clumped together). Radiation treatment involves multiple sources, as this does. But you do still need to control the phase. It is really sort of a combination of the two.

    • However, in order to get this to work well, you need the transmitted signal to be phased-aligned to within an appreciable fraction of a wavelength. ... Since we are around a gigahertz, that means that the phase of the carrier should be accurate to within a couple hundred picoseconds, max.

      Micrel SY89295U
      Programmable delay range: 3.2 ns to 14.8 ns in 10 ps increments in 2^10 discrete steps.
      160 ps rise/fall, less than 2 ps RMS cycle-to-cycle jitter.

      That gives you a spatial resolution of about 3 mm within a 3 m

  • Sounds like more of the same beamforming they've done for years, just more of it spread further apart.

    So DIDO, distributed in distributed out... sounds like MIMO with more antennas, more distance between them (surrounding the targets, even)

    I'm not sure why this isn't an obvious extension of MIMO. Harder to do, sure... and cool that it's coming... but obvious in concept.

  • Explanation from TFA (Score:5, Informative)

    by tech.kyle (2800087) on Wednesday February 19, 2014 @02:31PM (#46288291)
    Should have been included in summary, imo.

    That’s where things get interesting. Say, for example, you play a YouTube video. The pCell data center would request the video from Google’s servers, and then stream it to your phone through those 10 antennas. But here’s the key innovation: No one antenna would send the complete stream or even part of the stream. Instead, the data center would use the positions of the antennas and the channel characteristics of the system, such as multipath and fading, to calculate 10 unique waveforms, each transmitted by a different antenna. Although illegible when they leave the antennas, these waveforms would add up to the desired signal at your phone, exploiting interference rather than trying to avoid it.

    • by Anonymous Coward

      Sure it can be done - for one user. How that set of 10 antennas could do it for 1,000 users simultaneously is beyond me.

      • In principle* if you have n antennas then you can completely control the waveform at n locations of your choice. So the multi-antenna techniques will have to be combined with one or more traditional multiple access schemes (CDMA, FDMA, TDMA) to serve realistic numbers of users.

        Still this has the potential to dramatically increase average throughput per antenna over more conventional techniques (at the cost of a LOT of processing power and very good interconnections between the cells)

        * Practice is a bit mess

    • But here’s the key innovation: No one antenna would send the complete stream or even part of the stream.

      So... the antenna sends nothing. Brilliant, now to hook it up to some torrent sites.

  • For when the GPS is turned off. Or maybe pCELL combined with GPS means that google maps won't send me the wrong direction down a deadend road again.
    • The wrong direction down a deadend road? So, once you left the area, you could never return?

      • The wrong direction down a deadend road? So, once you left the area, you could never return?

        I have a Jeep... There is no such thing as a wrong direction down a dead-end road... (grin)

    • by Immerman (2627577)

      Well, it'll be a lot more accurate, but it's already trivial to track the position of *any* cellphone in the city within at least block or so without using GPS. Being able to narrow that down to tracking its motion around the room is a lot creepier, but probably not a lot more abusable.

  • All that's left is figuring out *who* will be suing him first. CISRO? Intellectual Vultures?
  • I know the NSA is behind this ... I mean, tracking phones down to centimeter precision.
  • we need to focus our technology on designing base stations and cellphones that utilize directed-energy, focusing their signals at each other, versus using omnidirectional energy (this creates a lot of waste, and the energy penetrates and bombards people/things it doesn't necessarily have to,..).

    with an imaging system like this, the base station can see each device independently, like a satellite does from over head, and an array of light-guns or phased array antennas can direct energy at each device for ded

  • This sounds very like the existing 3G soft handover feature.

    I'm not involved in that area of telecoms these days, but I do recall that the network equipment manufacturers were finding it very difficult to get working, and requiring some serious compute power.

  • by DriveDog (822962) on Wednesday February 19, 2014 @03:22PM (#46288871)
    As cool as the technique sounds, for me it's a solution to the wrong problem. Maybe some of you have trouble getting your videos streamed in congested cities, but I don't use my phone for that. My complaints are all about poor coverage in rural and even some suburban areas. And I have Verizon, which because it unfortunately swallowed Alltel (I'm not aware of any Alltel customers that were happy about that), has much better coverage in my area than the rest. What they need is a few hundred thousand more nodes in rural and suburban areas on ordinary utility poles, inside of steeples, etc.
    • Due to the nature of population distribution, the issue you described is relevant only to a small minority of users. Over 80% of Americans live in urban areas (as of 2010 [reuters.com]), despite urban land accounting for only 2.65% of the total US land area. In other words, your issue is your issue, and most people don't share your priorities.

      While you have my sympathy, you can't expect wireless carriers to ignore the majority of their customer base and start chasing after the long tail.
    • by Kjella (173770)

      Well, it might not be you but I've seen the traffic numbers and there's an absolutely massive increase in mobile traffic. When people were on laptops, they mostly used wireless nets. Now with smartphones, phablets and tablets with built in 3G/4G connections they tend to get used a lot. And many of them are high PPI devices, meaning you're still sending HD signals even if it's on a 4-10" screen.

  • by ras (84108) <russell-slashdot@@@stuart...id...au> on Wednesday February 19, 2014 @07:59PM (#46291227) Homepage

    This reminded me of the claims Steve Perlman [venturebeat.com] made in 2011. He said his technique would overcome Shannon’s Law. He was justifiably ridiculed. At least this mob isn't claiming they can break the laws of physics.

    Oh wait, this is Perlman [venturebeat.com], peddling the same dog and pony show. Only this time he's got an article in IEEE Spectrum to print his claims. I hope that means he no longer says he can beat the laws of physics into submission.

    The original claims of the impossible aside, the idea was to monitor the signal of each phone in real time from a central point, do some calculations to figure out the path distance from each antenna the phone, then do some more calculations to split up and phase change outgoing signal so the signals from those antennas so they constructively interfered to produce the wanted signal at the phone. The tracking has to be damned accurate - much better than GPS because a 1Ghz mobile phone signal has a wave length of about a meter, and you need better than 1/4 of the wavelength. And it has to be fast, because if the phone or objects around it move it all goes to put. So if you are walking at comfortable 1 metre per second, in 0.25 seconds it's all gone to pot. In a car that drops to 0.02 seconds. Oh, and since we as talking 1GHz, we have to measure it within a few 100 picoseconds. And since you don't use one antenna to service just one phone, he will have to be doing this for 100's of phone simultaneously. Oh, and that means when he is calculating the phase and amplitude of the signal his antenna is generating, he has to solve 100's linear equations with 100's of variables so he can ensure each signal he sends from each antenna adds up to what each phone needs. And since the collective antenna group is sending at oh, say 100Gb/s and he has to do this for every fucking bit, so he has 10 picoseconds per bit to do it in.

    Yeah, right. It will be out by Xmas, I'm sure.

  • So they're bringing super fast speeds to a device 50x slower than my PC that's almost impossible to type on and has a processor that makes a playstation 2 look good. Great idea. And before you say it, you'd have to be an idiot to put your whole house on a 4G wifi hotspot. I'd use the cap in about 1 day under normal use. The cell network isn't built for that kind of traffic. They should be putting money into battery research and better encoding and bandwidth usage so towers are more effective and phones

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