"Subconscious Mode" Could Boost Phone Battery Life

cylonlover writes "University of Michigan researchers have proposed a new power management system for smartphones that could dramatically improve battery life. The system, known as E-MiLi, or Energy-Minimizing Idle Listening, addresses the energy waste that occurs when 'sleeping' phones are looking for incoming messages and clear communication channels. E-MiLi slows down the clock of a phone's WiFi card by up to 1/16 its normal frequency in order to save power, but then kicks it back up to full speed when information is coming in. The phone uses the header of the incoming message to wake itself up from its 'subconscious mode,' so the clock is at full speed to receive the main message. For users on the busiest networks, it could extend battery life by up to 54 percent."

Comments

fractions

[Anonymous Coward]

by 1/16th? or up to 1/16th of? - - quite a difference there!

Old ideas live again

[dtmos]

Patent 4,893,271, issued in 1990 and expired, covers an implementation of this idea in which the slow clock is a crystal oscillator, and the high-speed clock is synthesized, using the crystal oscillator as the reference of a phase-locked loop. It was used in tens of millions of Motorola radio pagers for exactly the reason stated in the article -- lower power consumption in sleep mode, while retaining the ability to process fast once a signal appears.

Re:Old ideas live again

[Hazel Bergeron]

And even in 1990 the idea that one could slow down the clock of a synchronous digital processor was obvious.

Re:Old ideas live again

[dtmos]

Yes -- the trick is doing it without keeping the high-speed oscillator running all the time. In these kinds of embedded applications, the oscillator can draw a significant amount of power. Implementations that have a high speed oscillator running all the time, but divide it down while in sleep mode, draw more power than the invention, which has a low speed oscillator running all the time, and only generates high frequencies when they are needed.

Re:Old ideas live again

[Anne Thwacks]

I am pretty sure I worked for AT&T on digital pagers that did this well before 1990. We used a 4-bit micro and a modem that was mostly software. The entire protocol was designed to allow the pagers to "sniff" in time slots based on the pager address. I went on to work on "selective call radios" (cellphones) for Motorola which did the same thing in about 1988.

Re:Old ideas live again

[V!NCENT]

This idea still realy sucks balls due to crappy WiFi signals never recieving anything. What we need is an expecting system. If you're not texting a while, just check once per 1,5min and do nothing else in between. Let it have a tickless OS.

Oh wait, we already have that and it is called Linux (tickless)

Should be a realy extremely obvious thing...

Re:Old ideas live again

[dtmos]

You can also switch the low speed osc off while the high speed one is running if you're obsessive.

Yes -- if you're willing to pay for two crystal oscillators. The advantage of that patent is that you get by with one crystal.

Re:Old ideas live again

[dtmos]

I am pretty sure I worked for AT&T on digital pagers that did this well before 1990.

I went on to work on "selective call radios" (cellphones) for Motorola which did the same thing in about 1988.

Quite possible -- the priority date for the patent is 7 November, 1983.

Re:Old ideas live again

[Dunbal]

What, and force the telcos to invest in the infrastructure to do more work storing the messages and to take the load from all those incoming requests? NEVAR!

Re:Old ideas live again

[V!NCENT]

While funny, SMS is being send over GSM, in the same package that is being exchanged with cell towers to maintain GSM (/2G) connectivity, irregardless. That package has empty space, so SMS (that's why it's limited by an amount of characters; so it can fit in that package) can be send without extra load on the cell tower buffer.

What we are talking about here is stuff like Watsapp and Ping and that shit, which is stored on a central server anyway, so when cellphone asks server "What's up, man?" it then gets send without having to fill up the buffer, which is once per 1,5 minutes.

Re:Old ideas live again

[MrHanky]

No, this is something completely different. This is an even slower mode, set to watch only the headers of incoming packets sort of like a Slashdot system, in which people read the first couple of words of an article, then wakes up to comment on said article at full speed to get first post, just with the tiny tweak that it actually reads the rest of the message before replying.

Re:Old ideas live again

[philgp]

-15 karma points for using the (non-)word "irregardless".

Re:Old ideas live again

[vlm]

which is also painfully obvious to anyone in the field. microcontrollers have had multiple clock inputs and internal oscillator blocks with support for switching between them built in for decades. You can also switch the low speed osc off while the high speed one is running if you're obsessive.

Its also painfully obvious to the RF engineering crowd. "obviously" if you have a multiplier chain the high freq mults are going to draw more power than the low freq mults. mults are never known for efficiency so if you have a couple stages you'll find most of your power is dropped in them not the osc. Also you wanna keep the crystal running all the time so its stable, constant temp, etc. Heck keep the first mult stage or so running to keep the load on the osc stable, if you want. That way the calibration output is theoretically usable all the time, instead of being FM modulated as you turn the mults on and off.

Anyway, when you're actively TX or RX, then, and only then, power up the higher freq multipliers in the RX or TX chain (assuming you have 2 separate chains, you just got an instant 50% power savings at the cost of some complicated power wiring). If you're leaving the xtal powered up 24x7 to enhance stability, then powering down the multipliers seems terribly obvious... so that's exactly what they did in ye olden days. When I was a kid I fooled around with some even then obsolete motorola VHF TX and RX strips that had this "obvious" power saving feature.

I don't have a cite, but pick up VHF/UHF/microwave oriented ham radio manuals from about half a century ago, you'll probably be successful.

Merely terminating the last mult stage in a microprocessor clock input instead of a RF mixer is not exactly insightful or patent worthy. Its the equivalent of patenting the concept of using AA batteries in a flashlight instead of their traditional use in kids toys.

The patent is probably much more specific to get around the staggering quantity of prior art. Probably specs the exact layer 2 framing protocol complete with diagrams of the sync header and stuff.

Re:Old ideas live again

[JerkBoB]

It may surprise you to learn that many of the words we think of as totally acceptable were once like irregardless.

That doesn't make them any less stupid. Anyone with even a basic understanding of prefixes and suffixes should flag "ir-" + "regard" + "-less" as nonsensical in context. "not" + ("regard" + "without") == "with regard", or worthy of consideration. It's right up there with "I could care less" in the retarded language department.

For the record, I twitch at most uses of the word "decimate" as well. It's rare that one would get to use it properly in most conversation, and rarer still that it would both be used properly and understood properly by the recipient. I don't use it, personally.

Re:Old ideas live again

[russotto]

Its also painfully obvious to the RF engineering crowd.

Oh yeah, if they're so smart why don't RF chipsets include this feature right on the die? What's that you say, they DO? This is is merely the application of an existing technique to a problem solidly within its domain? Don't care, patent approved.

Just like the owners

[Mike Mentalist]

Some of the text messages I receive read as if the sender was only subconscious.

hw r u 2day? batt rnning low lol

Re:Just like the owners

[Hazel Bergeron]

hw r u 2day? batt rnning low lol

Sender is a midget artificial intelligence and is distressed that her bath is leaking.

There's a hole in her bucket, dear Eliza.

What, weren't they doing this already?

[Lord Lode]

Seems like common sense...

SetCPU in Andoid Market

[GuyFawkes]

Does exactly this thing...