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Breakthrough Promises Smartphones that Use Half the Power

samzenpus posted about 2 years ago | from the save-the-juice dept.

Power 110

Dupple writes in with news about a discovery that should extend the life of your battery in the near future. "Powering cellular base stations around the world will cost $36 billion this year—chewing through nearly 1 percent of all global electricity production. Much of this is wasted by a grossly inefficient piece of hardware: the power amplifier, a gadget that turns electricity into radio signals. The versions of amplifiers within smartphones suffer similar problems. If you've noticed your phone getting warm and rapidly draining the battery when streaming video or sending large files, blame the power amplifiers. As with the versions in base stations, these chips waste more than 65 percent of their energy—and that's why you sometimes need to charge your phone twice a day. It's currently a lab-bench technology, but if it proves itself in commercialization, which is expected to start in 2013—first targeting LTE base stations—the technology could slash base station energy use by half. Likewise, a chip-scale version of the technology, still in development, could double the battery life of smartphones."

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Not another one... (-1, Redundant)

GodfatherofSoul (174979) | about 2 years ago | (#41839355)

When I see "battery breakthrough" in the headline, I don't even bother with the summary. [sigh]

Re:Not another one... (5, Insightful)

Scytheford (958819) | about 2 years ago | (#41839381)

Too bad the article has nothing to do with battery technology, and you look a fool.

Re:Not another one... (1)

Intrepid imaginaut (1970940) | about 2 years ago | (#41839759)

Besides which batteries have been steadily growing in capacity year on year for decades, which is why we have smaller batteries doing much more intensive work in phones today. On that note, I predict not longer life for phones from this technology, but smaller batteries yet.

Re:Not another one... (0)

Anonymous Coward | about 2 years ago | (#41842571)

Besides which batteries have been steadily growing in capacity year on year for decades

Err... No they haven't. Capacities pretty much leveled since the introduction of Li-ion.

Re:Not another one... (2)

Verdatum (1257828) | about 2 years ago | (#41843633)

Also too bad that, like all the "battery breakthrough" articles, this one has no real content beyond a bunch of unsubstantiated claims and the name of a startup company with nothing but a placeholder website.

I'm not quite as quick to call bullshit on this claim as I am with the articles claiming to solve the energy crisis. I spent four years writing code for modules that interacted directly with bastations, but without even a taste of a technical explaination why there is something wrong with the amplifier, it's a coinflip.

I wish this sort of journalism came with citations, so I could no for certain whether the author is dumbing things down to avoid scaring away the non-technical audience, or because they are lazy bastards who copy-pasted a press release without bothering to investigate if there was any validity to the claims.

Re:Not another one... (1)

XDirtypunkX (1290358) | about 2 years ago | (#41839383)

The word "battery" never appears in the headline, so maybe you didn't read that either.

Re:Not another one... (0)

Anonymous Coward | about 2 years ago | (#41839493)

Not the head line, but article itself:
"Dupple writes in with news about a discovery that should extend the life of your battery in the near future."

Re:Not another one... (0)

Anonymous Coward | about 2 years ago | (#41839985)

Yeah, extend the life of your battery, cuz they haven't changed. So you'll have a new phone and a battery from your old phone! Then if you swap them you can double the life of both batteries!

Re:Not another one... (0)

Anonymous Coward | about 2 years ago | (#41839385)

"Breakthrough Promises Smartphones that Use Half the Power"

Just sayin

Re:Not another one... (1)

gagol (583737) | about 2 years ago | (#41839447)

"Breakthrough Promises Smartphones Radio Chip that Use Half the Power"

Last time I checked, smartphones still have a cpu, screen, memory, etc... It would still add to longer lasting batteries, just not the whole system.

Re:Not another one... (1)

icebraining (1313345) | about 2 years ago | (#41839641)

No, they promise a radio chip that uses less than half the power, which is why it could cut down on the overall consumption by 50%. It's perfectly possible, as long as the chip currently uses a big enough percentage of the total energy consumption.

Re:Not another one... (1)

Andy Dodd (701) | about 2 years ago | (#41842025)

Radio power usage is probably 70-90% of a device's standby power usage.

So it'll be great for standby time/background data power costs, not so much when the screen is on.

Re:Not another one... (0)

Anonymous Coward | about 2 years ago | (#41842091)

It might save 50% of the power when it is used in a base station that is actively transmitting to all the different mobile phones out there.

In a cell phone, the PA isn't on 100% of the time when the phone is in standby mode. The PA in the transmitter only needs to wake up from time to time to handshake with the base station. I would not expect the same 50% savings not unless you start talking/surfing 24/7 on a cell phone.

I would be surprised if the average person talk more than a couple of hours a day on the phone. So that's only 10% of the day that the phone is actively transmitting. Even then as many posts have pointed out, the blacklight, GPU, CPU and other toys in the cell phone also chew up power.

Re:Not another one... (1)

icebraining (1313345) | about 2 years ago | (#41842375)

We're talking about Smartphones. Talking is hardly the only activity that requires active transmission. Facebook, Twitter, email, music streaming, Latitude-like apps, all require regular transmission of data.

Re:Not another one... (1)

Neil Boekend (1854906) | about 2 years ago | (#41839455)

Okay, that's your choice. But what does that have to do with this article?

Call the statistics police (4, Interesting)

mattr (78516) | about 2 years ago | (#41839371)

Why do I not believe that 1% of global electrical production goes to powering wireless base stations.

Re:Call the statistics police (1)

aXis100 (690904) | about 2 years ago | (#41839465)

Yeah, I dont believe them either.

Re:Call the statistics police (4, Informative)

Decker-Mage (782424) | about 2 years ago | (#41839541)

Probably due to the fact that all of IT consumes about 1% of all power globally. And notice in that statistic "about" which, if it comes above 0.0000...01% somehow gets magically gets rounded up (apparently using ceil (APL) function rather than a real rounding function). If they really want to save power generated capacity, they really should look at replacing all those power bricks out there with something remotely efficient before thinking about the power consumption drawn from an, also admittedly, inefficient battery, on the way to the power amps.

Matters not much, methinks, as no one is going to take advantage of the new designs until (1) they are incorporated into "stock" parts and (2) they are cheaper than the designs they are replacing. Almost forgot, and no one is still running a fire sale on the old chips.

Articles like these, long on promise, short on economics, or long on threat, and short on the same thing, economics, piss me off.

Re:Call the statistics police (1)

drinkypoo (153816) | about 2 years ago | (#41840561)

Why do I not believe that 1% of global electrical production goes to powering wireless base stations.

Probably due to the fact that all of IT consumes about 1% of all power globally

[citation needed] [newscientist.com] - yours is the only estimate I have seen which is so low.

Economical for off-grid base stations? (1)

Guppy (12314) | about 2 years ago | (#41842601)

The initial market will be in the developing world, where 640,000 diesel-powered generators are used to power base stations, chewing through $15 billion worth of fuel per year.

This quote from the company gives the economics away. The monetary savings from the new base station amplifier's efficiency likely do not offset the increased purchase cost -- for stations wired to the grid. So they're selling it as a way of decreasing cost and re-fuel frequency for off-grid stations.

Re:Call the statistics police (1)

siddesu (698447) | about 2 years ago | (#41839905)

More importantly, why don't I believe that halving what the phone radio uses will double battery life?

Screen? (1)

brunes69 (86786) | about 2 years ago | (#41840437)

On more modern / powerful phones with larger screens, it is not the radio that is the dominant problem anymore. It is the screen.

If you are "Streaming video" for any length of time with a 4.5" screen phone, it is the screen using most of the battery, not the radio. Screen battery use is also bad because it even affects you in airplane mode.

This seems to be solving yesterday's battery problem - but any gain is good I guess.

Re:Screen? (0)

Anonymous Coward | about 2 years ago | (#41840657)

You're right, but as the OLED materials process matures, the ratio of screen power to RF output power will decrease quite a bit. This is definitely a nice breakthrough even if a few years away.

Re:Screen? (1)

default luser (529332) | about 2 years ago | (#41842105)

In addition to this, another key part of improving transmission has been improvements in DSP processing power to lift usable signals out of the noise. Unless you can find a unique way to improve the efficiency of the algorithm they use, you're going to have to wait for a die shrink to improve power consumption of that portion of the cellular chipset.

Re:Screen? (1)

tlhIngan (30335) | about 2 years ago | (#41842851)

On more modern / powerful phones with larger screens, it is not the radio that is the dominant problem anymore. It is the screen.

If you are "Streaming video" for any length of time with a 4.5" screen phone, it is the screen using most of the battery, not the radio. Screen battery use is also bad because it even affects you in airplane mode.

Not to mention that cellular radios are extremely power efficient because they have to be. The power amp is only used for transmission, and only powered up the instant the radio needs to transmit, then shut down immediately afterwards.

The amount of power that streaming video takes is extremely low as the radio is mostly in receive mode, not transmit (it's sending acks and such but that's it).

In standby mode, the power budget is around 3mA or so to get your 300/500 hour standby time, and the radio is consuming roughly 90% of that as it has to maintain a ping to the base station, which involves transmitting. Of course, the power consumption spikes easily to 100+mA, but for such a brief period of time that it averages out as the radio basically keeps the transmitter powered off until it absolutely needs to transmit, and the receiver off as long as possible (receive power is still high, so the receiver is shut off when the phone isn't expecting an update from the base. If the base has a message, the base will hold it until the phone's timeslot comes up - power savings at the expense of latency).

The real technological wonder is being able to quickly turn on and turn off those parts of the radio - considering that traditionally you had to let them "warm up" to get on frequency. These days it's practically instantaneous.

Nah. (1)

DNS-and-BIND (461968) | about 2 years ago | (#41839377)

What's going to happen is, about ten seconds after this technology is deployed, the cell phone companies will halve the number of cell towers using the argument that the new tech makes them unnecessary. Your battery is again drained as weaker signals mean more amplification is necessary.

Re:Nah. (0)

Anonymous Coward | about 2 years ago | (#41839421)

and that's bad how exactly?

Re:Nah. (1)

backslashdot (95548) | about 2 years ago | (#41839593)

Did you read his last sentence?

Re:Nah. (0)

Anonymous Coward | about 2 years ago | (#41839467)

No, because if you would RTFA, you would see that the efficiency gains are in reducing idle power consumption.

Re:Nah. (3, Interesting)

realityimpaired (1668397) | about 2 years ago | (#41840295)

My phone can go about 5 days if all I do is idle. That's with Bluetooth and 3G data services/sync turned on, but wifi radio turned off. If I nix Bluetooth and/or data services, I can increase that.

I'm all for reducing power consumption, but if it's not going to reduce the power consumption when the device is actually being used to transmit, then how is it going to increase battery life noticeably when most smartphone users plug it in every day anyway? Besides which, the screen is what eats up the lion's share of my battery... simply decreasing the brightness of the screen makes a huge difference in the life of the battery.

Re:Nah. (4, Informative)

Neil Boekend (1854906) | about 2 years ago | (#41839485)

Nope, because it doesn't increase the range of the antenna. The same limits to transmitted power apply, no matter what technology you use to transmit it.
Besides, in heavily populated area's the number of antennas has nothing to do with transmit power, but with maximum throughput.

zeemee (-1)

Anonymous Coward | about 2 years ago | (#41839389)

hanks for the kind words and I am happy you liked the article.NICE JOB
http://www.thebooks4free.blogspot.com/

Android battery stats (0)

Anonymous Coward | about 2 years ago | (#41839395)

What would this affect in android battery stats, because the screen uses more than 1/2 and the rest is split between like 20 other things. I don't understand how this could double the battery life.

Re:Android battery stats (5, Funny)

Anne Thwacks (531696) | about 2 years ago | (#41839511)

You must be new on planet news: could save up to 50% means "will probably save less than 5%, but we need a grant".

Re:Android battery stats (1)

icebraining (1313345) | about 2 years ago | (#41839695)

Does the screen really use more than 1/2? Or is that only when the phone is being used?

During about 90% of the day, my phone is in idle, with the screen turned off but still pinging the network.

Re:Android battery stats (1)

bluefoxlucid (723572) | about 2 years ago | (#41840897)

No, they're all just morons.

My Galaxy Nexus with AMOLED screen starts at 100% charge while plugged into USB charging and in 10 minutes is at 99% ... in an hour it's below 95%... if I'm running the Facebook app. That's with the screen off most of that time, too. The Facebook app chews a TON of data, and pushing the H+ 4G that hard drains battery faster than it can charge.

I removed the Facebook app and put in the Facebook Messenger app instead. Much more benign, almost no data usage.

Re:Android battery stats (1)

Ironhandx (1762146) | about 2 years ago | (#41841371)

bluetooth + screen + call drains the battery faster than it can charge as well.

Re:Android battery stats (1)

bluefoxlucid (723572) | about 2 years ago | (#41842703)

I just made an 11m 37s call and Voice Calls went from 0% to 13%. I can believe it.

What technology? Who built it? (5, Insightful)

complete loony (663508) | about 2 years ago | (#41839409)

If you're just going to pick a few sentences out of the article, you should at least talk about "who" and "what". All we've been left with in the summary is "problem description" and "hype"

Please keep me warm... (4, Funny)

zippo01 (688802) | about 2 years ago | (#41839437)

But what will keep me warm on those long lonely nights while I watching inappropriate things on my phone?

Re:Please keep me warm... (4, Funny)

ozmanjusri (601766) | about 2 years ago | (#41839459)

Friction.

Re:Please keep me warm... (-1)

Anonymous Coward | about 2 years ago | (#41840527)

Pam and her five sisters.

Re:Please keep me warm... (0)

Anonymous Coward | about 2 years ago | (#41844441)

Back in the day it was PalmofMyHanderson

Re:Please keep me warm... (1)

mrbester (200927) | about 2 years ago | (#41839809)

Increased blood flow.

Screens (0)

Anonymous Coward | about 2 years ago | (#41839441)

Sorry, but Smartphones spend most of their energy to power the screen, not anything else.

Watson arrives (2, Funny)

Anonymous Coward | about 2 years ago | (#41839443)

IBM Watson group announce Watson has solved Smartphone battery problems! Using the magic of connected-world technology, Watson now developed batteries that think-smarter.

Soon Watson will be moved to self-driving cars, where it will be given the far more difficult task of following a white line around an empty track at superfast speeds! The connected technology painted stripe we leverage allows our world beating Watson to go around faster* than the competitors!

* You may not benchmark it and no stopwatches will be allowed into the demonstration.

It's network (1)

wannabgeek (323414) | about 2 years ago | (#41839463)

This improves the standby and talk time, and may be network power consumption. Most of the other stuff the apps use - like CPU, GPU, sensors will not be any different because of this. So to claim double of battery life is exaggeration. It may double the standby time and probably improve the talk time by a considerable percentage.

Re:It's network (1)

bluefoxlucid (723572) | about 2 years ago | (#41840981)

Cell phones have fast CPUs so they can be interactive, not so you can run Folding@Phone on them.

I dont blame power amplifiers (4, Insightful)

aXis100 (690904) | about 2 years ago | (#41839499)

Pretty sure most of the power used is not in the radio - before "smartphones" we had phones with similar battery capacities achieving much longer standby times AND talktimes. Even if you turn off a smartphone's Mobile data and stick to Wifi (with only 30mW transmit required), battery life still isn't great.

I think it's got a lot lot more to do with:
- Big, bright displays
- Multicore, gigahertz CPU's regularly kept busy with background apps
- Far more sensors embedded in the unit to power - GPS, accelerometers, etc.

Re:I dont blame power amplifiers (1)

SuperAlgae (953330) | about 2 years ago | (#41839839)

I agree with your general point, but non-smartphones do not have overall longer talk times than smartphones. They do have long standby times though.

Re:I dont blame power amplifiers (5, Insightful)

icebrain (944107) | about 2 years ago | (#41840135)

I think it's got a lot lot more to do with:
- Big, bright displays
- Multicore, gigahertz CPU's regularly kept busy with background apps
- Far more sensors embedded in the unit to power - GPS, accelerometers, etc.

Plus, the whole obsession with "the phone must be THIN!!!1!"
If the manufacturers quit worrying about trying to fit the phone into the form factor of an index card, there would be enough thickness for a reasonable battery.

Re:I dont blame power amplifiers (1)

Aranykai (1053846) | about 2 years ago | (#41840987)

Pretty much every android device out there is now rated above 7 hours talk time. I don't know what planet you come from, but that is easily double what smart phones did 4 years ago when they weren't dominant of the cell market.

Motorola actually did what you are suggesting in their Droid Razr model, offering one with a 2.5x capacity battery called 'Maxx" or some such. Very few people sprang the extra money for the extra battery because 8 hours talk time was already sufficient. Most people aren't power users like we are.

Re:I dont blame power amplifiers (2)

icebrain (944107) | about 2 years ago | (#41841505)

I only got a smartphone two-something years ago. Prior to that, I had a dumb phone with extended battery; after three and a half years, I still got 3-4 days between charges. When new, I charged it once a week, and that was with heavy talk usage. So even today's smartphones seem to have short lives compared to that.

I have an extended battery on my current phone (rooted Samsung droid charge), and I still have to charge it every day, at least during the week (but that's also because I now work in a large metal building with very poor signal inside). I don't use much data, either, but "cell standby" is usually in the top two list of power consumers on my phone.

I'd be happy with just an extended battery option on future phones, though it would be nice if things like cases and covers were available for phones fitted with said batteries.

The "thin!" mantra is getting ridiculous, though; when I got my current phone I asked about an extended battery and the sales people just got a blank look. "Why would you want that?" they asked. "You could get the wireless charger and then the phone would still be thin! You could get a car charger! Why would you make the phone not thin?!" It blew their minds that someone might not care about thinness, or might even prefer a little thickness.

Re:I dont blame power amplifiers (2)

plover (150551) | about 2 years ago | (#41843385)

Agreed. Phone thickness is not the dimension I have a problem with. Length, width, and mass are my most important constraints. The iPhone 3 and 4 is about my ideal size - the iPhone 5 is a bit too long for convenience and comfort. However, the iPhone 4 would certainly benefit from a larger viewable screen area - thinner borders, and using more screen area near the earpiece and home button.

What I'd really rather have than a more massive phone would be a replaceable battery. I'd happily keep a spare battery in a dock at home, another in a dock at work, and a third battery in my backpack. Running low on charge? Change it out, wherever I am. If Apple is so damn concerned about sealing their phones so only Apple dealers can change out the batteries, how about instead providing a suite of expensive accessories I'd happily buy?

Re:I dont blame power amplifiers (3, Interesting)

Spacelord (27899) | about 2 years ago | (#41840269)

It really is mostly the displays. On Android phones you can see what is using the battery, and it's almost always 60-70% the display.

As for those multicore CPUs, modern smartphone operating systems are remarkably good at keeping them clocked down when they're not needed. As a matter of fact, if I leave my Galaxy Nexus unattended (i.e. don't use the display), there hardly is any battery drain. I wouldn't be surprised if it would last a whole week that way.

Re:I dont blame power amplifiers (1)

Aranykai (1053846) | about 2 years ago | (#41841003)

Beg to differ, On my last two devices, display usually ranked 2nd or 3rd to cell standby and phone calls. Only on occasions where I had an extended game session or a movie did it ever break 30% usage.

Re:I dont blame power amplifiers (1)

bluefoxlucid (723572) | about 2 years ago | (#41841017)

If you leave your Galaxy Nexus unattended and plugged into USB to charge with the Facebook app running in the background, I'd be surprised if it lasted a whole day. The first time I installed the FB app, I didn't even use it and my phone started struggling for power (slowly losing charge WHILE CHARGING). Looked in data usage, found that in 5 minutes the FB app had pulled 4 times my total data consumption for the past MONTH from all other apps. Deleted that shitfest.

In 1 hour I lost more than 5% battery charge mostly idling with the screen off.

Smartphones that Use Half the power (5, Funny)

TheInternetGuy (2006682) | about 2 years ago | (#41839523)

Breakthrough Promises Smartphones that Use Half the Power

Seems inefficient, wouldn't it be better if they used all the power?

I Welcome this 'breakthrough in energy saving' (1)

nssy (1530925) | about 2 years ago | (#41839525)

Its about time we use our phone battery power for productive work instead of wasting it in a grossly inefficient piece of hardware: the power amplifier.

Class C (4, Insightful)

GrahamCox (741991) | about 2 years ago | (#41839611)

Class C RF power amplifiers can be ~90% efficient, because they drive a tuned load. That's been known for most of the 20th century. Is the problem that these need to be wideband amps? Perhaps there is a clever way to reconcile those needs, though I'm not seeing it.

Re:Class C (2)

SuricouRaven (1897204) | about 2 years ago | (#41839765)

Might be related to those phones supporting four to six different mobile network technologies operating in many different bands.

Real measure of efficiency (1)

Anonymous Coward | about 2 years ago | (#41840105)

The measure that matters is "energy per coded bit". In that regard, Class C amplifiers suck because they can only send one bit at a time. With clever coding (eg. QAM), linear amplifiers can send many bits at once.

Linear amplifiers waste as much energy as heat as they create in RF. Engineers have dealt with that for many years. They did it for satellites way before there were cell phones.

The various cell phone protocols are designed with power conservation (battery life) in mind. I would be surprised if someone found a way to dramatically improve the situation without a major breakthrough in semiconductors. ie. If they could use class D or E, they could improve efficiency but that would require switching speeds ten times what we can now achieve.

web.eecs.umich.edu/~stark/HKU_Talk1.pdf

Re:Real measure of efficiency (0)

Anonymous Coward | about 2 years ago | (#41840521)

Well a class C amp can send QPSK, but even with offset OQPSK you still get enough envelope to cause spectral re-growth. That's the main issue; spectral regrowth in crowded bands.

Re:Class C (4, Informative)

Gordonjcp (186804) | about 2 years ago | (#41840155)

No, the problem is that they need to be linear. You can use class C for FM (and therefore GMSK) because you're running at full carrier power continuously. For 3G, you need a linear amp because QAM has potentially got a variable carrier level. There are tricks you can do to get round this (envelope restoration) which could be what TFA is on about, but it's slashdotted.

Re:Class C (0)

Anonymous Coward | about 2 years ago | (#41840489)

Yep. The 35% efficiency they mention in the summary is actually pretty good for an amp used for anything that requires phase information to decode the bits.

Re:Class C (1)

Andy Dodd (701) | about 2 years ago | (#41842229)

Yup. As a point of reference:

A typical FM station's power amplifier is Class C and can achieve 70-90% efficiency. BTW, the new digital "HD Radio" is a nightmare for these guys, as while the OFDM signal used only needs 1-10% of the RF transmit power to achieve the same range, with typical amp technology back in 2003 or so, that meant 15-20% efficiency at best.

For UMTS signals, which have a pretty high peak-to-average ratio, if a PA achieved 17-20% efficiency, that was REALLY good back then. There were a few tricks that had hope of pushing into the 20s around 2003, such as Doherty architecture amps (http://en.wikipedia.org/wiki/Doherty_amplifier).

Another trick is outphasing (which sounds like it is part of what is being described here). With outphasing, you have two Class C amplifiers running full tilt, and their phases are varied so that they either add together or cancel out to achieve amplitude modulation of the output signal. It's also known as LINC - LInear amplification with Nonlinear Components.

The problem is how to combine these signals - with a traditional hybrid combiner, you have sum and difference outputs. Sum goes to antenna, difference has to go to a dummy load as wasted power. So you don't gain much efficiency over a Class A, B, or AB amp. However your power dissipation is now in a dummy load at the end of a coax cable instead of at the amplifier's transistor, so you do have a heat management benefit.

You can just connect the outputs together, but then you have VSWR mismatches when the amps are out of phase. If you construct a matching network right, you can have maximum efficiency at maybe 80% power, and good efficiency from 60-100% output power. This worked well for the aforementioned digital radio systems - if you combined the OFDM signal in the guardbands and a legacy FM signal, the signal envelope would never drop to zero, and would vary from 60-100% amplitude. You could get good efficiency with these signals and the lossless approach, but needed to compensate for distortion. Predistortion would do the trick - http://www.google.com/patents/US6930547 [google.com] - This didn't work well for raw OFDM signals or CDMA signals such as UMTS back then. The zero crossings presented too much strain on the amps. Best case you had horrible efficiency, worst case you fried the output stages of the amps.

I haven't worked in that industry for nearly a decade, but it looks like this new approach combines another known trick with outphasing/LINC (TFA mentions both modulating the power supply voltage AND outphasing) - vary the amplifier voltage depending on the signal envelope, to increase efficiency at lower signal envelope operating regions (and keep the amplifier from blowing itself up).

Re:Class C (1)

MattskEE (925706) | about 2 years ago | (#41843825)

Based on the article it sounds a lot like envelope tracking:

The new advance is essentially a blazingly fast electronic gearbox. It chooses among different voltages that can be sent across the transistor, and selects the one that minimizes power consumption, and it does this as many as 20 million times per second. The company calls the technology asymmetric multilevel outphasing.

But looking back at one of their papers: http://www-mtl.mit.edu/~jldawson/Dawson_digest2009.pdf [mit.edu] it is not exactly envelope tracking. They are starting out with an outphasing amplifier (dividing the signal into two constant amplitude variable phase signals which can then be amplified with an efficient nonlinear amp and recombined into the original signal) and then adding a discretely variable drain bias (much like an envelope tracker) but the purpose of the variable drain voltage is actually to minimize power dissipation in the combiner's isolation resistor. Thus they compare their efficiency and linearity only to outphasing types of amplifiers. I would be curious to see how this stacks up to pure envelope tracking amplifiers.

Re:Class C (4, Informative)

smpoole7 (1467717) | about 2 years ago | (#41840567)

> Class C RF power amplifiers can be ~90% efficient, because they drive a tuned load. That's been known for most of the 20th century. Is the problem that these need to be wideband amps?

You're on the right track, but the answer is a bit complicated. (The article, by the way, sounds like a PR piece for someone expecting to patent a technology that, by the same arguments we use against software patents, probably shouldn't be patentable, because it's an obvious rearrangement of existing technology. I shall elucidate.)

1. Yes, it's difficult to run wideband amps in class C. Class C works best with a single frequency at a constant level.

(To illustrate: my wideband HD transmitter, for example, must be re-biased to class AB. I can switch it to "pure" class-C FM mode and it puts out 2-3 times the power as when it's in HD mode.)

2. As a general rule: designing an efficient amplifier becomes more difficult the higher the frequency. Wireless phones run at high frequencies.

(To illustrate: class D switching amps have made it possible for your teenage son to have 1,000 watts of audio in his Nissan Sentra. But you must use a switching frequency that's much higher than the signal -- easy to do with audio, not so easy with even just an 800-900 MHz wireless signal.)

3. Read the fine print and look beyond the smoke.

We just went with Modulation Dependent Carrier Level (MDCL) on our 50,000 watt AM, and it has indeed cut our power bill substantially, which is strikingly analogous to what these people are proposing. But this is highly dependent on modulation (i.e., what we're "playing" at any given moment, whether music or voice) and other factors.

In this case, if they're obtaining the higher efficiency by "smoothly" switching between standby and active modes, one wonders how efficient it will be during rush hour, when everyone is on the phone, calling their significant other to have dinner ready when they get home. :)

Re:Class C (2)

bluefoxlucid (723572) | about 2 years ago | (#41841097)

(The article, by the way, sounds like a PR piece for someone expecting to patent a technology that, by the same arguments we use against software patents, probably shouldn't be patentable, because it's an obvious rearrangement of existing technology. I shall elucidate.)

There's a scam going on where people sell these big capacitor banks as "Power Savers" to reduce your electricity bill. They work on solid principles. Such things are used in steel mills where big driver loads run by heavy motors have a low power factor. Correcting the power factor greatly improves actual operating efficiency. Some of these mills shut down operations when the power saver fails because it's more expensive to operate without power factor correction than it is to idle the plant. In a residential setting, however, the general whole-house power factor corrector isn't helpful: most loads aren't the type that need tuning, and the box isn't tuned to match the specific load; plus things like refrigerators and computer PSUs now use power factor correction circuitry in them, and of course the boxes they sell for your house are engineered poorly and are generally not great products anyway.

Consider, though, that power factor correction saves so much money that idling a steel mill is less financially damaging than running it without power factor correction.

Hint: If these people bring in shit that drops cell phone tower electricity usage by a significant factor and it actually works, it's not obvious.

Commercial operations eat a ton of power. They pay a premium for being high-load customers. Anything that significantly reduces that load is going to get everyone who understands finances jizzing in their pants.

Re:Class C (1)

smpoole7 (1467717) | about 2 years ago | (#41841873)

> If these people bring in shit that drops cell phone tower electricity usage by a significant factor and it actually works, it's not obvious

But the phase correction that you're talking about is mostly used with big reactive loads. Yes, you can save a ton of money in that case. But except for the HVAC and (possibly) the UPS units that back up the power, that doesn't really apply to cell sites. Besides, the application discussed in the article is for the transmitters only. Has nothing to do with these other, MUCH higher-demand devices. (The average transmitter in a typical cell site isn't very powerful.)

What they're talking about here IS obvious. It is a rework of existing technology. I could build what they're talking about with chips from Digikey or Mouser. It's simply a different variant on the old, "make the power match the demand." But yes, I have no doubt that it probably WILL be patented, but that's more a function of our horribly broken patent system than of the novelty of this "new" idea. :)

I also predict that, if they try to take someone to court to enforce their patent, it'll be another crapshoot, because I could show prior art that strongly implies what they're hawking. Then it's just a question of whom the court believes (and all bets are off ANYTIME that's the case with a patent trial).

Re:Class C (1)

Andy Dodd (701) | about 2 years ago | (#41842271)

The basic concept of modulating the supply voltage is obvious... Getting it to actually WORK properly without excessive distortion of the output signal is *not*.

You might be able to build what they're talking about with chips from DK or Mouser - but the actual techniques for using those ICs in concert with each other without making the output signal garbage are not obvious.

Seriously - you're going to need a $80k-120k spectrum analyzer and a $30-50k signal generator just to be able to properly test the system. Cheaper stuff won't even be able to meet your output Adjacent Channel Power Ratio (ACPR) requirements coming out of the signal generator, and cheaper spectrum analyzers will have too high of a noise floor to properly measure the ACPR.

Re:Class C (1)

bluefoxlucid (723572) | about 2 years ago | (#41842767)

that doesn't really apply to cell sites

Which is the point. All that shit doesn't apply to cell towers, but cutting back their power usage would be worth a lot of money. Therefor since we can imply great demand for an imaginary product--anything you can shove on-site at expensive private-owned major infrastructure and drop your continuous costs by enough to offset the cost of the magical widget is de-facto "in great demand"--we can imply that if that product does not exist, it is not obvious. If you know how to do it but it's extremely expensive/unstable/unreliable/etc, THEN YOU DON'T KNOW HOW TO DO IT.

Re:Class C (1)

dj245 (732906) | about 2 years ago | (#41844331)

There's a scam going on where people sell these big capacitor banks as "Power Savers" to reduce your electricity bill. They work on solid principles. Such things are used in steel mills where big driver loads run by heavy motors have a low power factor. Correcting the power factor greatly improves actual operating efficiency. Some of these mills shut down operations when the power saver fails because it's more expensive to operate without power factor correction than it is to idle the plant.

This is only half true. Industrial and large commercial customers are often billed based partly on their power factor. This is because poor power factors are less efficient for the utility. Residential customers are not billed by the power factor. Lousy power factors in residential areas are still less efficient for the utility, which is why they sometimes install capacitors on the poles. You have probably seen them and never noticed- google photos [google.com]

Putting Power factor correction in the home isn't going to help your bill at all, since residential customers aren't billed by the power factor.

Re:Class C (1)

bluefoxlucid (723572) | about 2 years ago | (#41844565)

The point stands. If there's a way to save a business thousands a month per location in operating costs on electricity, and it's not been implemented, it's not obvious. With example.

Re:Class C (1)

Technician (215283) | about 2 years ago | (#41843533)

Class A amps are the least effecient. Class AB is common for high fidielity, but still run in a transistors linear reigon generating heat.

The high power car stereo industry has been using switch mode PWM transistors to drive high power sub bass for a long time. This is not new tech. It is new tot he cell phone industry.
Class D is switched Mode PWM.
Class G&H are variable Switched mode power supplies that vary the voltage provided to the amplifiers to increase effeciency.

These classes do not have the frequency range and noise floor of Class AB amplifiers.

Thats nothing! (-1)

Anonymous Coward | about 2 years ago | (#41839785)

My phone lasts for 3 weeks on a charge!
My DUMBphone. that does exactly one task. phonecalls.

Explain again why i want almost a full computer in there too so my battery life is measured in days or hours instead?

Something tells me it's not the radio that's sucking up all the power.... It's all that other shit that got crammed into a PHONE.

Double the power? (0)

Anonymous Coward | about 2 years ago | (#41839787)

Does that mean that my phone will keep a charge until even after lunch?

Bullshit (0)

Anonymous Coward | about 2 years ago | (#41839871)

Even if all this is true, it's not going to make smartphones last twice as long. Why? Because the screen uses way more power than the radio. Halving the power usage of the radio will do little to extend the battery life.

Wrong description. (0)

Anonymous Coward | about 2 years ago | (#41839877)

The power amplifier turns electricity into more electricity (or rather, turn DC into heat and AC based on a low-energy AC template). It is the job of the antenna to turn electricity into radio signals.

The actual paper... (1)

Anonymous Coward | about 2 years ago | (#41839887)

...is here: http://dspace.mit.edu/bitstream/handle/1721.1/62479/712059703.pdf?sequence=1

A Gadget? (4, Insightful)

jamesl (106902) | about 2 years ago | (#41840081)

... the power amplifier, a gadget that turns electricity into radio signals.

Any article that calls an important piece of technology a "gadget" is neither serious nor credible.

Re:A Gadget? (0)

Anonymous Coward | about 2 years ago | (#41840975)

Not to mention that the antenna, not the power amplifier, turns electricity into radio signals.

Re:A Gadget? (0)

Anonymous Coward | about 2 years ago | (#41841321)

http://en.m.wikipedia.org/wiki/Trinity_(nuclear_test)

Envelope tracking (5, Informative)

Iconoc (2646179) | about 2 years ago | (#41840171)

What this article never really manages to describe is Envelope Tracking (ET). This has been in development for several years. Look at the diagram in http://www.nujira.com/technology-pa-746.php [nujira.com] for a better description of the concept. This article describes the application of ET in the handset.

WiFi enabled devices too? (0)

Anonymous Coward | about 2 years ago | (#41840315)

This could be useful for more than cellphones. I'm hoping it applies to devices with WiFi capability as well. With wireless turned off, my tablet goes for about 8 hours no problem. But as soon as I do any web browsing I'm lucky if I get 3 hours out of it before needing a recharge.

Why? (0)

Anonymous Coward | about 2 years ago | (#41840387)

Oh, we must save big corporations from having to spend too much on electricity!

Will our cell phone plans be cheaper?

Re:Why? (1)

bluefoxlucid (723572) | about 2 years ago | (#41841119)

Your electrical utility bill may be cheaper when you take the strain off their infrastructure. Infrastructure companies like the status quo; when they build out, there's a long wait for ROI.

Battery usage (1)

RivenAleem (1590553) | about 2 years ago | (#41840445)

That's odd, every time I look at my phone's battery consumption it always tells me that my primary power drain is the screen.

Re:Battery usage (1)

bluefoxlucid (723572) | about 2 years ago | (#41841165)

The battery isn't controlled by the OS. Each time a process runs, the OS stops another process and schedules the waiting process onto the CPU, setting up all the page mappings and registers and then context switching into userspace at saved EIP. It knows how much CPU is used for what task because it schedules it. As for the battery, it roughly understand how much power various components are supposed to draw and makes an educated guess.

My Galaxy Nexus tells me Phone Idle 50%, Cell Standby 22%, Screen 15%, Bluetooth 8% (I don't even have a bluetooth dongle active..), Android OS 4%, Maps 2%. 10h 26m 13s on battery. Wifi has been off and I haven't had much active use of data coming down (one app syncs a meg or so every 6-8 hours; GMail is very light).

30% just for two of the radios to idle.

asymmetric multilevel outphasing (1)

epine (68316) | about 2 years ago | (#41840611)

"The technology" turns out to be called "asymmetric multilevel outphasing". No wonder the submission was too embarrassed to include this tidbit. Small problem, though. Nerds don't omit.

Empathy represses analytic thought, and vice versa [eurekalert.org]

Even for nerds it turns out that dog paddling through life in the default network generates more discussion forum page views. Somewhere a kitten dies.

It's not the bulk of what takes up phone power (1)

ebinrock (1877258) | about 2 years ago | (#41840811)

If you ever go into your settings to see battery usage, you'll notice it's not the radios or the amplifiers, it's the *display* that uses the vast majority of the battery power. Sure, we need to get more efficient radios, but let's really go after getting the display technology much more power efficient, while at the same time coming up with a much more efficient battery technology than lithium ion or lithium polymer. Graphene and other battery technologies in the works look promising.

Re:It's not the bulk of what takes up phone power (1)

bluefoxlucid (723572) | about 2 years ago | (#41841189)

50% "Phone Idle," 22% "Cell Standby," 15% "Display," 8% "Bluetooth" in 10 hours. 30% radio versus 15% screen and the amount of data transferred is under 5 megs.

Re:It's not the bulk of what takes up phone power (1)

DeadCatX2 (950953) | about 2 years ago | (#41842009)

Samsung Galaxy SIII. Running on battery for 26 hours, 10 minutes. 61% charge remaining.

Cell Standby 59% (battery used by cell radio)
Android System 20% (battery used by apps)
Device idle 7%
Screen 6% (time on 45m 32s)
Exchange 4%
Android OS 4%

So in my case, for the past 24 hours, the radio has consumed ~10x as much battery power as the screen (which was on 3% of the day, a not insignificant amount)

Isn't the backlight really the problem? (1)

Richard_J_N (631241) | about 2 years ago | (#41840839)

I always thought it was the backlight that used the power? My phone can be on standby for 3 days, yet 1 hour of ebook reading in flight mode kills the battery.

Heat? (1)

thegarbz (1787294) | about 2 years ago | (#41840907)

If you've noticed your phone getting warm and rapidly draining the battery when streaming video or sending large files, blame the power amplifiers

No. I'll blame the bits that actually make heat, such as the screen backlight, and the CPU and GPU when displaying video.

If the amplifier running at 50% efficiency when you're running maximum 0.125W for HSDPA or 0.25watt for GSM is causing your phone to heat up then you're doing it wrong!

Re:Heat? (1)

oreiasecaman (2466136) | about 2 years ago | (#41842857)

If the amplifier running at 50% efficiency when you're running maximum 0.125W for HSDPA or 0.25watt for GSM is causing your phone to heat up then you're doing it wrong!

No, no... you're holding it wrong. :)

It's the screens.. (1)

grasshoppa (657393) | about 2 years ago | (#41841007)

Except for most modern smart phones, screens take up a bulk of the battery's power.

sounds like old tech (1)

Shavano (2541114) | about 2 years ago | (#41841105)

This sounds like old technology. They have been doing what sounds like the same thing in audio for years.

Charge 2x per day? (1)

MachineShedFred (621896) | about 2 years ago | (#41841205)

I haven't had to charge my phone twice in one day in over 5 years, when I moved away from a piece of crap Motorola Razr.

This might come as a huge shock: don't play games on your phone for hours at a time, and you don't burn the battery down.

screens to be transflective (0)

Anonymous Coward | about 2 years ago | (#41842871)

my old nokia has a transflective color screen, i can read it in direct sunlight putting backlight use to a minimum, sure its poor to use but at least i can read basic things which is better than no choice at all (cant do anything without backlight being on) the battery still lasts 6 days
make it work in sunlight and phones could stay on for weeks

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