New Chip Promises Longer Battery Life 188
Roland Piquepaille writes "It always happens when you need it the most: the battery of your cellphone just died. But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power than current designs. The new chip relies on a technology named injection locked frequency divider (ILFD) which dramatically reduces the time needed to check for transmission frequencies which are performed several billion times per second by your current phone. The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits, allowing a perfect communication between two phones communicating at 2.0001 and 2.0002 gigahertz respectively."
Not A Big Deal (Score:5, Informative)
Bruce
Re:Not(?) A Big Deal (Score:1)
Re:Not(?) A Big Deal (Score:5, Interesting)
I'm not quite as negative as the grandparent poster, in that I'm happy if any component uses less power (every bit helps) but in reality, it's the transmitter that uses the lions share of the juice, not the reciever (even in standby).
Re:Not(?) A Big Deal (Score:2)
Comment removed (Score:5, Informative)
Re:Not A Big Deal (Score:5, Funny)
Re:Not A Big Deal (Score:5, Funny)
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
If an end-to-end mobile phone system was a used Portland taxi, the meter would never come off polling, the user would be the rear view mirror and you would be an old penny lost long ago under the right front seat.
Re:Not A Big Deal (Score:5, Informative)
The article is really short on details. The real power hog in a cell phone is the transmitter - it will draw 3Amps of current - while the rest of the receiver and up-conversion components are maybe 10% of that. And transmitters are already quite efficient - generally, ~50% of the input DC power winds up going out as RF power.
The lower power version of the PLL will be useful, since it needs to run constantly, even while not actively in a call.
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
no it doesn't... (Score:3, Informative)
Let's say I'm running at 1W (max for 1800/1900, half max for 850/900). I'm transmitting 1/8th of the time (due to TDMA slotting).
Thus I would use 1/8Wh per hour just to transmit. My phone has a 3Wh battery (800mAh @ 3.8V). So I would have a talk time of 24h, if my phone didn't use power for anything else at all. It does, so the talk time on my phone is 8H.
Now, let's try out your version. I'm using 22W when transmitting, 1/8th of the time. So I'm using 2.8Wh per hour. So, if my ph
Re:Not A Big Deal (Score:4, Informative)
Re:Not A Big Deal (Score:3, Informative)
Actually, you would expect it to be roughly X/sqrt(10). Standard error decreases with the inverse of the square root of the sample size.
Re:Not A Big Deal (Score:2)
You were doing ok until that part. It stands as contradictory with the next content, however...
The new method described in the Article is roughly analagous to modifying all of your pennies to ensure that the variation in the weights of the pennies is much lower, so you can rely on just one pe
Re:Not A Big Deal (Score:3, Informative)
Re:Not A Big Deal (Score:2)
i'm very confused :-S
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:2)
Re:Not A Big Deal (Score:3, Informative)
Thanks
Bruce
Re:Not A Big Deal (Score:2)
bad heuristic (Score:2)
Furthermore, it doesn't tell you whether a component is responsible for high overall power consumption; in order to be responsible for high overall power consumption, a component doesn't need to use a lot of power itself.
Re:bad heuristic (Score:2)
Consider that microprocessors are CMOS digital devices, we're not unused to getting some heat
Re:Not A Big Deal (Score:3, Informative)
Thanks
Re:Not A Big Deal (Score:2)
Let's look at the audio a bit more. First, you don't really need a linear amplifier there, you can use a transistor in switching mode and low-pass filter the output. That's more efficient, and doesn't use any significant power during silent times. So, you
"ten times less power"? (Score:2, Interesting)
Re:"ten times less power"? (Score:1)
At least. It might one eleventh. Numerical comparisons using less and more, rather than the accurate "as much" form, tend to be ambiguous.
Re:"ten times less power"? (Score:2, Insightful)
Re:"ten times less power"? (Score:2)
Re:"ten times less power"? (Score:1)
Re:"ten times less power"? (Score:5, Funny)
Re: (Score:2)
Conversation (Score:5, Funny)
Bloke: Who?
Dude: Yes
Bloke: so who invented this chip.
Dude: Hui did.
Bloke: Thats what I'm asking you.
Dude: Yer I know, Hui did.
Bloke: Quit it and tell me who invented the chip.
Dude: Im not joking, Hui did.
Re:Conversation (Score:1)
Re:get your pronounciation right (Score:3, Funny)
2: No "Hway"!
1: YES way!
2: That's what I said
1: What?
2: The name of the guy is pronounced "Hway", not "Hoo"
1: Oh. I thought it was "Hoo"
2: No it's "Hway"
1: I see
2: Yes. Well
1: Ok
Battery power (Score:1, Flamebait)
Ok, but that still doesn't solve the "I need my phone now but I was too lazy to charge it last night" problem. So what, this chip can run from a dead battery? No.
It really doesn't matter how much power the phone uses... the fact is that it still uses power. Consuming power from a limited source mea
Re:Battery power (Score:3, Insightful)
You're absolutely right. I don't even know WHY they're bothering! *places hands on his and sadly shakes his head*
Re:Battery power (Score:2)
Re:Battery power (Score:2)
Undoing moderation to Comment #15182612
Undoing moderation to Comment #15182623
Undoing moderation to Comment #15182652
Undoing moderation to Comment #15182671
Fuck. I totally fucked up last post. Guess I shoulda logged out.
Re:Battery power (Score:2)
Re: usb to 9v battery charger (Score:5, Informative)
http://www.hackaday.com/entry/1234000520028239/ [hackaday.com]
Or a WIND UP charger
http://www.edirectory.co.uk/pf/pages/moreinfoa.as
or a WIND TURBINE PHONE CHARGER
http://www.bytesurgery.com/gearedup/2006/02/a-win
Re: usb to 9v battery charger (Score:2)
Why are we still using batteries? (Score:2)
But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power than current designs. The new chip relies on a technology named injection locked frequency divider (ILFD) and permits to dramatically reduce the time needed to check for transmission frequencies which are performed several billion times per second by your current phone.
Out of curiousity, why have we not yet figured out how to wirelessly power devices? I mean, we can send lots of RF energy t
Re:Why are we still using batteries? (Score:3, Funny)
Re:Why are we still using batteries? (Score:2)
Dude, you just re-invented RFID tags! You'll make me smile next time I unlock the doors at work.
OK:
Re:Why are we still using batteries? (Score:2, Interesting)
Re:Why are we still using batteries? (Score:5, Informative)
Out of curiousity, why have we not yet figured out how to wirelessly power devices?
Short answer: We already have, it is just so inefficient that nobody uses it. (in fact it was invented over 100 years ago!)
Long answer: Electromagnetic waves radiate outwards. Either you have a simple non-directional antenna that radiates in all directions at the same time (in a sphere basically) and you lose power REALLY fast, or you have a directional antenna that radiates power in a cone at a target destination.
The omni-directional radiators suck so much that they are absolutely useless. Inverse square means 1/(x^2). Basically (and this is crappy math but gets the point across) if you have 10 watts at 1 feet, you would have 10*(1/(2^2)) = 2.5 watts at 2 feet. At 3 feet you would have 10*(1/9) = 1.11 watts. Please ignore that you would use meters instead of feet and that all my units are all messed up in various other ways as well. The point is that your power drops off REALLY fast.
So what about those directional antennas?
Well, you have to find some way to really accurately track someone's cell phone position, and have a world-wide array of directional antennas so that you can beam power to them no matter where they are at.
Oh and remember to keep those power levels low, else you will fry anything that gets in the way.
People worry about cell phones causing cancer as it is, directional power beamed at your head WOULD cause some serious issues!
Wireless power is possible, just not feasible!
Re:Why are we still using batteries? (Score:2)
Re:Why are we still using batteries? (Score:3, Insightful)
As you said, it's pure geometry.
Re:Why are we still using batteries? (Score:2)
The Sun seems to be having some success. (Score:2)
But I suppose we'd need to violate plant patents to be able to interface with its system...
Re:Why are we still using batteries? (Score:5, Interesting)
One of the devices that surprised me was a 50' long aerial, attached to some simple circuitry. The aerial absorbed RF energy, and the electronics converted it into a somewhat useful DC power supply. I think it was producing somewhere around 1 volt, no idea how much current, indoors. IIRC, they said it was "almost as good as a AA battery".
So, not only is is possible in theory, it's possible in practice. But it's still wildly impractical.
I think it's episode 24 (http://dsc.discovery.com/fansites/mythbusters/ep
Re:Why are we still using batteries? (Score:2)
eghads Brain... imagine a beowulf cluster of these things. You could use it to decode the very rf signal that powers them thus creating a sustainable way to spy on everyone and thus please both the liberals and the conservatives at the same time... and then TAKE OVER THE WORLD.
works ok over short range. (Score:2)
and you need enough power to get the signal back. so your equation would be something like
new transmit power at base station= old transmit power at source station divided by old receive power at phone multiplied by old transmit power at phone = massive.
and thats not accounting for the losses inherent in going from radio to electricity and back.
its feasible for ve
Re:Why are we still using batteries? (Score:2)
Re:Why are we still using batteries? (Score:2)
Billion? (Score:1, Offtopic)
Re:Billion? (Score:2)
Two/Three (Score:5, Funny)
Bender: "Ahhh, what an awful dream. Ones and zeroes everywhere... and I thought I saw a two!"
Fry: "It was just a dream, Bender. There's no such thing as two."
One idea (Score:2, Interesting)
In that case, make the antenna directional.
But then, we do *not* know the direction to which I have to sent the signal.
That can be done by maybe -
1. Changes needed for Towers
Sent downstream a small pilot signal of the same freq as the upstream signal which the phone emits for that call.
2. Changes needed in the Cell
Have a direction sensor in your mobile for this pilot signal. Once
Re:One idea (Score:3, Interesting)
A combination of multiple "antennas" with a 120degree coverage (for three) rather than a single antenna with 360 coverage, and phased array (look at phased array radars) could make this possible. Power savings though, might not happen because of the processing required.
-dave
Re:One idea (Score:2)
Yes, it is possible to have a directional antenna without it physically having to move in order to change directions. I think they have been around for a long, long time. Mutliple antennas/elements are required. (phased array?) . But the consumer wants a cell phone, not a porcupine.
I *think* something might be done like this in current MIMO research. I believe the problem of finding the direc
Re:One idea (Score:2)
Which would probably have all of the advantages that you were thinking about. If the tower can be more sensitive, then the cell phone can use less power, etc.
The towers also have the benefit of extra room for antennas, extra processing power, and might even be able to collaborate to determine the direction to the cell phone (e.g. as being done for 911)
The technical term (Score:2)
"Ten times less" (Score:2, Funny)
What a crock (Score:4, Informative)
Second, the statement that a "phase-locked loop multiplies the pulse from a highly-stable reference clock, such as a quartz crystal oscillator, up to the desired frequency" is 100% false. The function of a PLL is to lock (in phase...) a divided down version of a totaly independent RF oscillator, called a VCO, to a divided down version of the reference clock. The distinction may appear subtle, but it's enormous. Multipliers are large, power consuming IC's, while dividers are fairly small and efficient. There are NO multipliers in a PLL, period. Also, PLL's can already do split division, it's called a fractional-N PLL.
Mobile, battery powered electronics will never achieve decent battery life beyond a few GHz. There are several effects coming into play, from cosmic noise to H2O and O2 molecular resonances to increased multipath effects, and most importantly path loss. RF power spreads in a spherical wavefront, so there is a 1/R^2 power falloff. BUT, you need to recognize that this is in terms of wavelength (lambda), which is mathematically equal to C/f (speed of light / frequency). The net result is that doubling the frequency on a radio link incurs a 4-fold power fallof for a fixed distance.
So if I want to go from say just under 2GHz w/ a current GSM system to say 8GHz, then I need an effective 16 times the power output from my transmitter. I say effective, because you can use antenna gain, but not in the mobile handset (it needs to be omnnidirectional), and base stations directionality is very limited, since they need to support many users on the same antenna, and can't steer the beam to all of them simultaneously. You wouldn't be allowed ot put out that much powr form a safety perspective, never mind the power consumption and heat requirements in the power-amplifier. Handsets are at 600 milli-watts now, we're not going to put out >10 watts!
Re:What a crock (Score:2)
never achieve decent battery life beyond a few GHz"? It would seem that
as base stations grow in density of coverage we will be able to drop
power requirements. Imagine a base station every 10 m (like e.g. in
every lamppost). Already today cell phone coverage is only good in
civilized places, i.e. where roads go, so this would not drop
quality of service compared to what we have now.
Re:What a crock (Score:2)
whereas with a 10M range like you propose even if you put one in every lamp post you'd lose coverage as soon as you walked to the middle of a small park or down an unlit sideroad.
Re:What a crock (Score:2, Funny)
Re:What a crock (Score:3, Informative)
Re:What a crock (Score:3, Informative)
The inverse square law is so because it describes the effect of the expanding wave front as it propogates through space. The energy of any particular shell is constant, but as the shell expands the energy becomes more spread out. The square law is a consequence of our three dimensional space. The area of a sphere (the pattern of a so-called isentropic radiator) is pi*r^2, so the unit density will be {something}/pi*r
Re:What a crock (Score:2)
Re:What a crock (Score:2)
Re:What a crock (Score:2)
Re:What a crock (Score:2)
Re:What a crock (Score:3, Informative)
Sorry, but this last point is wrong. The inverse square law for power is, indeed, in terms of power, not wavelength. Actual radiated power depends on the power input to the fin
Perpetuating the propagation loss myth (Score:4, Informative)
Repeat after me:
Propagation loss does not increase with frequency!
Propagation loss does not increase with frequency!
Propagation loss does not increase with frequency!
Think about it: If the propagation loss of an electromagnetic wave increased in proportion to its frequency, there would be so much so much attenuation at the THz frequency of light that we'd never see sunlight--or stars. Propagation loss is independent of frequency, except for scattering due to molecular and atomic resonances that are insignificant at the frequencies we're discussing. (There are also changes in scattering behavior that become relevant in indoor applications, like propagation around corners.)
What is dependent on frequency, however, is the performance of the antennas we use to transmit and receive electromagnetic waves. Antennas can be characterized by a parameter called effective area. Returning to the sunlight example, recognize that the output power of a solar panel is proportional to its physical area; the larger this area, the greater the fraction of the incident power transmitted by the sun is received by the solar panel and converted to available output power. Receiving antennas, and antennas in general (even wire antennas), have an effective area; it's the area required to produce the measured output power, based on the density of transmitted power (watts/unit area) at the location of the receiving antenna.
Antennas can also be characterized by their gain, a function of their directivity and efficiency.
Interestingly, based on these two parameters any given antenna can be placed into one of two categories: There are constant-area antennas, the effective area of which is constant with frequency, and constant-gain antennas, the gain of which is constant with frequency. Constant-area antennas have gain that increases with frequency; constant-gain antennas have effective area that decreases with frequency.
The source of the myth is that most portable consumer wireless products use constant-gain antennas, usually some variant of a dipole. While the gain of a resonant dipole is constant with frequency, as the frequency goes up its physical length, and therefore its effective area, goes down. 2.4 GHz dipoles are physically smaller than 900 MHz dipoles. They therefore have less effective area, and recover less power from the incident wave. It seems like the path loss at 2.4 GHz is greater, but it's really just a result of the antenna choice in the product design. If consumer products used constant-area antennas, like a parabolic dish of fixed physical dimensions, exactly the opposite result would be found: Since constant-area antennas have gain that increases with frequency, the recovered power at 2.4 GHz would be greater than that at 900 MHz, and we could start a myth that propagation loss decreases with frequency.
Interestingly enough, if the transmitter has a constant-gain antenna and the receiver has a constant-area antenna (or vice-versa), the recovered power at the receiving antenna terminals would be independent of frequency (i.e., constant), and we could avoid the generation of propagation loss myths entirely.
Re:Perpetuating the propagation loss myth (Score:3, Informative)
Re:What a crock (Score:2)
The article keeps talking about clock pulses. So.. The carrier is being generated as a square wave? It would seem to me that a lot of energy is being lost on filtering edges.
What's going on here?
Not to worry. (Score:2)
This is all incorrect. PR & media idiocy as us (Score:5, Informative)
I don't post here very often, but this time I couldn't handle this. (Maybe I should drink less coffee). There was probably some paper at that uni, talking about an incremental improvement in frequency divider design. Ok, cool ... we may or may not see in in a PLL chip in a few years. But the news release (TFA) and RP's writeup are rubbish. Actually, after a bit of Googling, it's all over the net. Next thing I expect, my PHB will ask me to change my totaly unrelated design to use ILFD. My signature notwithstanding, I'll try to pick out some of the c***p, and put some actual information in. BTW, I design 3G mobile terminal circuitry full time. And yes, I am an arrogant SOB. That doesn't make me wrong.
"...But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power [GC] than current designs."
So far so good.
The new chip relies on a technology named injection locked frequency divider (ILFD) which dramatically reduces the time needed to check for transmission frequencies which are performed several billion times per second by your current phone.
This statement is wrong 2 times. First of all, the time needed to check for transmission frequencies depends on PLL settling time. Nothing to do with divider technology. Even broader scope, it is a rare occurence in 3G that the phone needs to change RF frequency. It's WCDMA, so all cells from a given operator transmit on the same channel. Secondly, tthe checking for transmission does NOT occur "several billion times per second". The RF carrier frequency is several billion cycles per second (ie several GHz). But the carrier frequency is changed on every 10ms roughly, even when it needs to happen. That's 100 times per second. GSM is different, as it does frequency hopping normally, but that doesn't change the point: nothing to do with divider technology.
The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits
OK, agreed. Anyway, who gives a f**k. A modern PLL chip has a programmable divider, settable from 3 to several thousand. Yes, 3, because it is different technology.
That's not how mobile phones work. Mobiles establish connection with the cell (base station), then remain frequency locked to it, to compensate for temperature dependant frequency variation of their reference reference crystal oscillators - and Doppler shift, if they are moving. A "perfect" communication hardly ever depends on this. And frequency locking does not happen via changing PLL settings in this case anyway - too coarse steps, so other techniques are used.
Anyway, as other people posted already, the frequency synthesizer is not significant contributor to mobile terminal power consumption. Even old PLL chips only use a few milliamps [national.com]
The ILFD technology seems to be good for building efficient frequency dividers at higher microwave frequencies. That will probably not affect current mobile phones anyway, because all the current systems work around 1-2GHz. Higher up, it's difficult to achieve coverage. Again, other people already pointed this out.
If you want real news in this area, go to sites like this [rfdesign.com], or this [mwjournal.com]. Slashdot's editorial quality has degraded in the last few years so much that I am thinking about deleting it from my bookmarks.
[/rant]Re:This is all incorrect. PR & media idiocy as (Score:2, Insightful)
Calm down... Most people come to slashdot for the comments. The articles themselves only serve as a starting point for a discussion, which is often valuable since there are always people like you who really know what they're talking about.
Re:This is all incorrect. PR & media idiocy as (Score:2)
Take it from an old-timer. Slashdot's editorial quality has remained pretty much consistent for about its entire existence.
Ten times less power ??? (Score:2)
Can I buy a thousand of these new chips and use them to power my electric car?
Nonsense! (Score:2)
Personal guess: Sloppy journalism and a marketing depatment working hand in hand. This is non-news and none of the stated benefits is even possible.
Bad slash
Sounds like an application of ternary computing (Score:2)
Re:Thats interesting and all (Score:3, Informative)
Bruce
Re:Thats interesting and all (Score:2, Funny)
Re:Thats interesting and all (Score:1)
Re:Thats interesting and all (Score:4, Interesting)
Re:Thats interesting and all (Score:2)
Sorry, no. Bruce Perens (above) gave the correct explanation: stroboscope effect, caused by the rapid blinking of the LEDs.
The same can happen with any other colour.
If you look at an (in my case green) oscilloscope from
Re:Thats interesting and all (Score:2)
Re:why can't cellphones standby as long as pagers? (Score:2)
Re:A Trinary Digit (Score:2)
2 killertits is known as a Pandora
2 Megatits is known as a Morgan