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Startup Claims Bandwidth Breakthrough

Missing the Israeli president
12/17/2013 00:01 AM EST
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AZskibum
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Modulation marches forward
AZskibum   12/17/2013 10:40:41 AM
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A 10 dB advantage over 4096 QAM! Just when you think every clever modulation scheme has already been invented, someone comes up with a new breakthrough that shatters old barriers.

I look forward to seeing how this progresses through standardization & productization.

Bert22306
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Re: Modulation marches forward
Bert22306   12/17/2013 8:32:42 PM
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It would be interesting indeed. However, we do have Shannon's equation to compare it to, and we do know how close to the Shannon limit other existing techniques come. And we also know that MIMO, under conditions in which multiple propagation paths are very uncorrelated, can give the appearance of violating the Shannon limit, but actually does not.

So, when we get more details, a fair comparison can be made. Anything that is 10 dB better than existing possibilities, aside from MIMO, sounds like it violates the Shannon limit, to me. Aren't we capable of only a couple of dB from Shannon already?

It would be a true breakthrough if it did legitimately violate Shannon's limit, but that wasn't mentioned.

KB3001
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Re: Modulation marches forward
KB3001   12/18/2013 2:42:54 AM
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I agree Bert22306, we need to know more about this 10dB claim because it looks impossible.

y_sasaki
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Re: Modulation marches forward
y_sasaki   12/18/2013 12:55:26 PM
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Correct me if I made mistake.

 

Frii's equasion is C=Blog2(1+S/N), while C=data rate (bit/sec), B is bandwidth (Hz), S/N is simple signal-noise ratio (not in dB).

While is is easy to define B, but assuming S/N is trickey part. Typical WiFi usecase is signal level around -70dBm, while background noise floor will be around -90dBm, so SNR is about 20dB.

 

Based on 802.11ac standard, 256QAM MCS9 datarate is 200Mbps per stream with 40MHz channel, short GI, coding rate 5/6. Raw (pre-FEC) rate is 240Mbps.

240=40*log2(1+S/N)

log2(1+S/N)=240/40=6

1+S/N=2^6=64

S/N=64-1=63

S/N(dB)=10*log10(63)=17.99

 

So it proves 802.11ac MCS9 is within typical usecase, even though 2dB margin is pretty low. Of course "typical" usecase could be varied - you'll get -50 - -60dBm signal if your PC is close to AP (within 10ft) so MCS9 will be much more practical.

 

Theoritically, 4096QAM (64x64 constallation) is 16bit/symbol so it should have x2 datarate than 256QAM (16x16 constallaton, 8bit/symbol). Thus, we can assume 802.11ac 4096QAM must have x2 datarate than 256QAM MCS9.

480=40*log2(1+S/N)

log2(1+S/N)=480/40=12

1+S/N=2^12=4096

S/N=4096-1=4095

S/N(dB)=10*log10(4095)=36.12

 

It shows "4096QAM WiFi" will be inpractical (so I don't think WiFi will adopt more-than 256QAM modulation / stream). Even if their claim of +10dB advantage is correct, 26dB SNR will be still tough to find in public wireless networ (WiFi or LTE).

However, it will make sense to backhaul, where dedicated frequency band is used with much higher TX power and highly tuned directional antenna.

rick merritt
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Re: Modulation marches forward
rick merritt   12/18/2013 10:54:26 PM
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@y_sasaki: Nice job runing the numbers.

Does this mean 11ac is about at the limits of what can be done with WiFi and the new modulation scheme won't help? If so, what does that imply for our march to faster, faster, faster?

y_sasaki
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Re: Modulation marches forward
y_sasaki   12/19/2013 4:46:49 PM
@ick merritt,

I personally believe 11ac 256QAM is already pushing little bit too far.

As Shannon's equasion (C=Blog2(1+S/N) suggests, the straightforward way to increase datarate (C) is to use more bandwidth (B). This was tried and failed on UWB (initially 500MHz/channel, hoped more than 5GHz/channel for future), partly applied to 11ac (up to 160MHz/channel).

Using higher frequency natunally increase bandwidth/channel, so there is high hope we can achieve more than 1Gbps datarate at 60GHz freq (802.11ad), however its laser-beam like characteristics and extremely low penetoration capability (you only can use 60GHz in clear line-of-sight) will limit is application.

MIMO is another way to increase datarate, but more than 4x4 MIMO will be impractical, since we need set of antenna / receiver / transmitter for each stream.

 

My most honest answer to "how we can get more datarate?" is "use wire!" :-)

sridhar.ramesh
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Re: Modulation marches forward
sridhar.ramesh   12/19/2013 4:11:27 PM
4K QAM is 12 bits per symbol without coding - simply log2(4096).

The 10 dB signaling advantage to 2 X power or spectrum advantage to 4X distance advantage referenced in this article don't sit well with each other.

y_sasaki
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Re: Modulation marches forward
y_sasaki   12/19/2013 4:32:02 PM
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Thanks. You are right, 4096QAM is 64x64 constallation, 2^6 x 2^6 = 12bit/symbol. I also wrote "Friis equasion" instaed of Shannon... Maybe because I often refer to both equasions to verify "revolutionaly communication method" on news :-)

BOMBOVA
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Re: Modulation marches forward
BOMBOVA   12/21/2013 12:03:15 PM
n Physics, gets streached,    the disbelievers,  speak up.   

elsissi
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Re: Modulation marches forward
elsissi   12/21/2013 1:02:21 PM

This article and many similar others in the press in the last week, is an example of what you get when you have a marginally good idea and a lot of money to spend on unsubstantiated PR. There is only ONE patent issued in the company name and several applications (not patents). The patent describe a partial signaling transmitted and a maximum likelihood receiver implementation. It is NOT as claimed in the article which strung together all sorts of unsupported superlatives. What a shame!!

rick merritt
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Re: Modulation marches forward
rick merritt   12/24/2013 11:29:43 AM
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@elsissi: I invite you to do the Google patent search on the name of the CTO Amir Eliaz yourself and you will see 14 issued patents.

As for unsupported superlatives: I invite you to puncture holes in anything you see in the story or the patents. But please be specific.

dt_hayden
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Re: Modulation marches forward
dt_hayden   12/24/2013 11:48:17 AM
Elsissi - See the list of 15 published patents I posted already.  I have not had time to review them much, I am starting with 8,526,523.

One thing that does stand out is the new transmission method uses a metric of 10^-1 to 10^-3 symbol error rate which seems in stark contrast to the 10^-6 metric normally applied to BER for data transmissions.

It is also astounding to me that these patent applications could be filed in Jan 2013 and granted in Sept 2013, for what is claimed to be a revolutionary technology.  There is a lot to take in for anyone, patent examiners included.

Bert22306
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Re: Modulation marches forward
Bert22306   12/26/2013 6:12:00 PM
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Good point on the more lenient BER criterion. That's enough to make comparisons invalid. Still, the BER does tend to drop rather quickly at the limit. So it may not make a huge difference.

Macroblocker
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Re: Modulation marches forward
Macroblocker   12/28/2013 8:11:32 AM
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Does this company check out?  Is it based in the USA or Israel?

It looks like it's owned by Yossi Cohen and Amir Eliaz.

A possible address for the company came up as a residential address on Upper Vintage Rd in Laguna Niguel, California, 92677.




Bert22306
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Re: Modulation marches forward
Bert22306   12/26/2013 5:46:07 PM
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Uuuh, more like truth gets stretched.

If existing modulation and error correction schemes get well withing 3 dB of the Shannon limit, it makes no sense to annonce that some new scheme is 10 dB better!

rick merritt
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Re: Modulation marches forward
rick merritt   12/24/2013 11:33:04 AM
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@sridhar: I believe they were suggesting 10dB could be translated into higher data rates, lower power consumption or longer distances, not all three at once.

Bert22306
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Re: Modulation marches forward
Bert22306   12/26/2013 6:06:48 PM
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"I believe they were suggesting 10dB could be translated into higher data rates, lower power consumption or longer distances, not all three at once."

Well, perhaps the "power consumption" angle adds enough ambiguity to let this otherwise unsupportable claim slide. Perhaps. I'd have to do a survey to tell for sure. As to distance (SNR actually, combined with receiver noise), data rate, and channel bandwidth, that *is* the tradeoff made by Shannon's equation. Either all thee together, or fix two and vary only one, or fix one and vary only two, makes no difference. That's why the claim sounds wrong.

This sort of truth bending happens all the time. In an interview I heard on a supposedly revolutionary engine design, the interviewee implied that his engine's efficiency was way higher than the norm because it had a lot more "working area" than standard piston engines.

Too bad the interviewer didn't think to ask, "What does working area have to do with efficiency? It's all about compression ratio. Tell me your engine has higher compression ratio, and I might start to believe. And then I'll ask, how do you prevent detonation?" The problem is just accepting as fact the implied significance of some irrelevant measurement.

These claims of supposed "breakthroughs" are very rarely credible.

zewde yeraswork
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challenge
zewde yeraswork   12/17/2013 10:52:08 AM
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It seems like a major challenge that companies have to face to have to standardize their communications technology before they cand eploy it and to have to reveal through disclosure much of their advantage to their competitors in the process. It is worth aiming for smaller markets in that case.

 

LarryM99
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Long road
LarryM99   12/17/2013 6:51:03 PM
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This sounds very interesting, but this is a long road with the corpses of a lot of startups alongside of it. Until they go public with details it is going to be hard to see whose ox is going to be gored by this and if it will actually make it out into the world, and if it does, in what form. There are a lot of players in spectrum that have the capability to buy and bury inconvenient technologies or the political wherewithal to block them.

zewde yeraswork
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Re: Long road
zewde yeraswork   12/18/2013 9:39:26 AM
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Agreed. There is still a long way to go before this can see the light of day.

y_sasaki
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Bandwidth Breakthrough
y_sasaki   12/17/2013 7:55:40 PM
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Reminds me that UWB (Ultra Wide Band) fiesta back in 2002-2005, more than 20 modulation schemes are proposed from a number of startup companies with pretty smart people, but sadly, practically none of them survived. The "most popular" UWB scheme was so-called MB-OFDM, similar to WiFi but using faster keying speed (312.5nsec VS 4usec of WiFi), thus wider subcarrier bandwidth. Anyway, even MB-OFDM UWB did not make breakthrough as proposed Wireless USB standard.

dt_hayden
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Issued Patents
dt_hayden   12/18/2013 12:05:55 PM
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A list of 15 issued patents is here.
1 8,605,832 Full-Text Joint sequence estimation of symbol and phase with high tolerance of nonlinearity
2 8,599,914 Full-Text Feed forward equalization for highly-spectrally-efficient communications
3 8,582,637 Full-Text Low-complexity, highly-spectrally-efficient communications
4 8,572,458 Full-Text Forward error correction with parity check encoding for use in low complexity highly-spectrally efficient communications
5 8,571,146 Full-Text Method and system for corrupt symbol handling for providing high reliability sequences
6 8,571,131 Full-Text Dynamic filter adjustment for highly-spectrally-efficient communications
7 8,566,687 Full-Text Method and system for forward error correction decoding with parity check for use in low complexity highly-spectrally efficient communications
8 8,565,363 Full-Text Fine phase estimation for highly spectrally efficient communications
9 8,559,498 Full-Text Decision feedback equalizer utilizing symbol error rate biased adaptation function for highly spectrally efficient communications
10 8,559,496 Full-Text Signal reception using non-linearity-compensated, partial response feedback
11 8,559,494 Full-Text Timing synchronization for reception of highly-spectrally-efficient communications
12 8,553,821 Full-Text Adaptive non-linear model for highly-spectrally-efficient communications
13 8,548,097 Full-Text Coarse phase estimation for highly-spectrally-efficient communications
14 8,548,072 Full-Text Timing pilot generation for highly-spectrally-efficient communications
15 8,526,523 Full-Text Highly-spectrally-efficient receiver

 

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=0&f=S&l=50&TERM1=magnacom&FIELD1=ASNM&co1=AND&TERM2=&FIELD2=&d=PTXT

rick merritt
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Re: Issued Patents
rick merritt   12/18/2013 10:55:19 PM
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@dt_hayden: Thanks for links to the patents.

I'd love commentary on them from any astute comms EEs out there.

Bert22306
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Re: Issued Patents
Bert22306   12/19/2013 4:13:23 PM
All we need is results.

For comparison, the US digital TV standard requires about 15.1 dB of SNR to achieve reception, in a gaussian channel. US DTV uses channel bandwidth of 5.3 MHz (and guard bands that bring this up to the 6 MHz channel width), and a net capacity of 19.29 Mb/s. The Shannon limit for a 5.3 MHz channel carrying 19.3 Mb/s is 10.6 dB of SNR minimum, required.

So this now-20-year-old standard is already only 4.5 dB from the Shannon limit. Unless Shannon's limit can be proved to have been violated, there ain't any 10 dB gains to be had here.

DVB-T2, the new European DTV standard, gets even closer. Last time I checked, it was ~ 3 dB from the Shannon limit.

So, all of this tells me that we're not looking at any "breakthrough in modulation." We're looking at refinements, much like DVB-T2 refined DVB-T1. Marginally better FEC codes, clever tricks on twisting the constellation, better interleaving, and so on. Small improvements that provide a small but measurable improvement.

Also, a significant point here. The purpose of OFDM is NOT to improve spectral efficiency. It is to improve resistance to multipath distortions. There's no such thing as a free lunch. What you pay, with OFDM, is moving away from the Shannon limit. So if a new modulation standard goes back to a single carrier approach, with improved equalizers, no one should be surprised. Equalizers benefit from Moore's law, after all. They are bound to improve over the decades.

paragdighe
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SNR GAP
paragdighe   12/19/2013 5:00:39 AM
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The SNR gap to shannon capacity for QAM is ~9.5 dB @ 1e-7 probablity of error.

Lots of literature and links on this. 

http://www.stanford.edu/group/cioffi/ee379a/handouts/pamqam2.pdf

Today's codes achieve very close to this (I have heard). So coding+QAM4096~=capacity. So would be interesting to see which way this company goes especially if you decide to toss the popular OFDM-QAM combination. Who would want them for 1-2 dB improvement ?

 

Parag

paragdighe
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Re: SNR GAP
paragdighe   12/19/2013 5:12:50 AM
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I guess the catch is that QAM 4096 may be near impossible to implement taking into account the practical implementation issues (EVM etc etc). I think the benefit must be that Magnacom has a scheme theoretically almost equivalent to coded QAM4096. Thats a big deal.

Sheetal.Pandey
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Re: SNR GAP
Sheetal.Pandey   12/19/2013 2:17:43 PM
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well every battle in telecom industry is linked to bandwdth, if there s a breakthrough it will be a new revolutons for the technology.

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