2G vs 3G Power consumption


#1

does a 2G electron consume less energy than 3G electron? do we have any power consumption benchmark? thanks!


#2

I’m not exactly sure, should be pretty similar.

Since 2G cellular networks will be shutting down in the future I would stick with 3G versions if possible.


#3

Actually 2G is more power hungry than 3G

https://docs.particle.io/datasheets/electron-datasheet/#recommended-operating-conditions-

Peak current for 3G ~800mA for 2G 1800mA


#4

Interesting! All the more reason to go for 3G.


#5

interesting! thank you!


#6

Peak currents on 2G are higher, but bear in mind that it’s a TDMA protocol vs WCDMA, so generally average power on 2G is significantly less than 3G.

When you have an active WCDMA session, ie you’re either sending or receiving data, you’re generally burning hundreds of milliamps continuously.

On 2G, your power depends mainly on how much you transmit - unlike WCDMA, your transmitter is not on when you’re receiving data (but when you send ACKs, it will come on just for that small amount of data). This is called DTX (discontiguous TX).

On 3G, you will idle out into paging mode, often after ~10s of idle time, then to transfer data again you need to re-establish an active session, which takes a second or more typically.


#7

Thanks for that background info :+1:
So it does greatly depend on the way you use the devices.

So to answer the original answer, we’d need to know how the intended use will look.

I’d think if you have a device sleep for more than the default keep alive for the SIM, requiring a full reconnection cycle, do some sensor readings, publish them and go to sleep, the higher 2G peak current will play more of a role than with scenarios where your “online” time outways the time used for the “initial” connection.
The break even point between these two would need to be found empirically - I’d guess.


#8

Well, sort-of. Are you transmitting megs of data?

2G higher peak current is a pain to supply (ie your power supply must be sized for it) but generally, the device isn’t transmitting; even when it is transmitting, it’ll be usually 1 or 2 slots up (never seen more be assigned), so that’s an average current of 1/8 to 1/4 of the typical 1.55A, ie 193mA-387mA most likely. You add onto this the receive current, but that’s less than half the transmit and if you’re only sending kB of data, you’ll almost never “see” the transmit current.

3G typical is 600-700mA at maximum power, continuously when a data connection is up. Yes, it’ll be less than that at 0dBm, and you send data faster, but it’s a big chunk of power that does not vary depending on how much you’re sending. If you’re sending megs, then sure this works out well, but it sucks for times you’re not transmitting much data.

This is why 3G sucks for web browsing; lots of download, very little upload but you’re still transmitting all the time. A serious step backwards from 2G TDMA.

That said, there’s no substitute for actually measuring your use case, but if you’re on 3G there’s a big penalty for bringing a data connection up. Use it intensively when it’s up.