The charge on the Galaxy Note 3 is going to last a lot longer than you think – and not just because of the slightly larger battery Samsung is shipping with the handset. Buried within the radio guts of the phone is a tiny chip called an envelope tracker, and it will reduce the power necessary to keep the Note connected to the network by as much as 30 percent.
The envelope tracker in the Note was developed by Qualcomm, and it’s the first commercial implementation of the technology that I know of. What it does is essentially match the power pushed through the phone’s signal amplifier to the actual power needed to transmit a signal. That might sound obvious, but in practice it’s a very difficult thing to accomplish.
A mobile signal is a waveform riddled with peaks and valleys, so a typical phone amp maintains a uniform “envelope” of power that can capture its highest amplitudes. The problem is particularly pronounced with LTE, which suffers from what’s known as a high peak-to-average ratio.
The best explanation was given to me last year by Jeremy Hendy, VP of sales and marketing at envelope tracking pioneer Nujira: LTE is classical music. 3G is heavy metal. Classical music has long quiet interludes punctuated with wild crescendos, while heavy metal is pretty uniform in loudness. Heavy metal is going to sound just as good (or bad) on any amp, but classical music requires much higher power to capture its nuance.
“You need a high-powered amp for LTE otherwise the signal is distorted,” Hendy said. “That’s why the power on an LTE [handset] is so bad. For every 4 watts you put in you only get 1 watt out.”
So if you’re wondering why your new LTE phone has such crappy battery life (or comes with an enormous lithium-ion caboose) compared to your old 3G model, you have your answer. What does envelope tracking do about it? It basically wraps the power envelope around the waveform tighter than a latex bondage suit, resulting in relatively little power loss.
What does that mean for a device like the Note? Well, the biggest power suck from a smartphone is always going to be a backlit display, and with the Note’s plus-sized screen that’s a significant drain. But unlike the screen, the phone’s LTE or 3G radio is always on and always communicating with the network.
If you’re the type of user that has a lot of apps running the background, then the power savings will be significant. The Note will also run a lot cooler since it won’t be expending all of that extra energy. While streaming video is going to tax your phone’s processor and display, at least you won’t have the additional power drain of a hyperactive LTE radio.
Nujira believes that as envelope tracking technologies improve they could reduce the power footprint of mobile devices as much as 25 percent – that’s a 25 percent improvement in overall device battery life, not just from radio. That’s another quarter to half-day of battery life without charging, depending on the device.
We’re going to start seeing envelope trackers in a lot a more devices. Nujira and Quantance, another envelope tracking specialist, have started shipping their chips to device makers, and many other radio frequency module makers have developed their own products. Qualcomm may well have an edge over the competition, though, given its dominance in smartphone processors and LTE chips and its growing influence in the RF module space.
Feature image courtesy of Shutterstock user koya979