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New 'pCell' Technology Could Bring Next Generation Speeds To 4G Networks
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.
So like Warp 9.5 then?
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....
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.
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.
"-1 Troll" is the apparently the same as "-1 I disagree with you."
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.
If we colonize Mars, it won't be the World Wide Web anymore. UWW?
Well, I can't comment on the prices, but several things go into the voice quality...
1) Voice quality is actually pretty good if you stick to a POTS land-line. Back in the 60's, everything was analog, so the noise added up.
2) Cell phone reception certainly can be bad, but back in the 80's when cell phones were invented, you had giant phones that could pump out a couple of watts because you had a large antenna and large batteries. Modern phones have tiny batteries and tinier antennas. This is partially compensated by a better noise floor on the cell-site receivers, but there ain't no such thing as magic.
3) Old analog cell phones transmitted actual analog voice at full bandwidth. While a waste of bandwidth, it sounded pretty good. Modern phones compress the heck out of your voice before sending it. The last time I checked, it was using some variant of CELP, which sounds fairly good, but far from perfect.
4) Data is now packetized (part of the compression). If you loose any part of the packet, you loose about 1/4 second of voice or so. In analog phones, you would hear a pop. or 1/10 second of silence.
"-1 Troll" is the apparently the same as "-1 I disagree with you."
I think you meant "lose" rather than "loose" you can blame it on autocorrect if you want ....
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.
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?
(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 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.
Also: You can bootstrap it by putting the new computation into just the existing cells, letting you handle more connections than with the old scheme. (After that it's add more cells in the customary maner, with more bang per buck.) Not only that, you only need to do it in areas where you're already running out of base station capacity and starting to suffer service level problems due to oversubscription/congetioin. If replacing/upgrading the equipment in existing cells gives you more additional connections per buck than the alternatives, there's no adoption cliff at all.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
"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. It might turn out better.
This reminded me of the claims Steve Perlman 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, 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.