5 ms·

Are you sure they do that when wifi is off? I was under the impression that it only happens when wifi is on (and it seems to me that my location on the map is m

by comboy 10y ago

Are you sure they do that when wifi is off? I was under the impression that it only happens when wifi is on (and it seems to me that my location on the map is more stable with wifi on). That would be very not ok if it would happen with wifi off. I turn my wifi off to save the battery, and it wouldn't do much if it was still looking for broadcasts.

anexprogrammer 10y ago
There's another wifi setting, in advanced I think, for "scanning always available"
sly010 10y ago
Its a question of terminology. When you are passively listening to (periodic) SSID beacons, you are not transmitting anything, nor consuming any energy on your radio. One could do that even in airplane mode. It's very different from when you hit "scan" and are actively sending broadcast packets on every frequency and waiting for the wifi routers to (actively) answer. Which really only happens when you pull down the list of nearby hotspots.
- mirashii 10y ago
  > nor consuming any energy on your radio This simply isn't true. You'll be using power to demodulate at a minimum. You'll also be using energy to ammplify the incoming signals and a variety of other things.
  - klodolph 10y ago
    Yes, this is also the reason why GPS is so power hungry--it takes a lot of power to keep a GPS radio receiver operating.
    - jsjohnst 10y ago
      Close enough for a quick reply, but it's not the "radio" using lots of power, it's the chip that's doing the signal processing. GPS signals are very weak (approximately -120dbm) and thus below the noise floor. It takes complex FFT operations that actually cause the power hungry nature to find the proverbial needle in the haystack.
      - klodolph 10y ago
        Normally, "radio" includes the amplifiers and demodulators, even if they're digital.
- jhayward 10y ago
  > or consuming any energy on your radio Listening is actually one of the more power-intensive things a radio does, because it tends to be active more of the time than transmitting does. For many radios power consumption is the same whether transmitting or receiving.
  - omilu 10y ago
    >For many radios power consumption is the same whether transmitting or receiving This, is not right.
    - mynewtb 10y ago
      Please elaborate at least a bit.
tuxracer 10y ago
WiFi is never completely off until you disable "Scanning always available" https://i.stack.imgur.com/wcQkc.png https://i.stack.imgur.com/wcQkc.png
- jasonkostempski 10y ago
  I don't have that option under "Advanced Wi-Fi" but under Settings -> Location -> Scanning I have "Wi-Fi Scanning Improve location by allowing system apps and services to detect Wi-Fi networks at any time". Is that the same thing? Nexus 5X, Android 7.0
  - khedoros 10y ago
    Ditto, Nexus 5, Android 6.0.1. That's how I interpreted it: as a relocation and rewording of a setting.
kllrnohj 10y ago
> I turn my wifi off to save the battery Sending/receiving data over wifi takes roughly ~8x less power than sending/receiving data over cell. If you want to save battery you need to turn off data entirely not turn off wifi. Turning off wifi ultimately costs you battery.
- comboy 10y ago
  Not if I'm out of range of my home wifi which is practically the only wifi I connect to. I think my phone last longer like that, but I never actually measured it, so maybe it's not worth it after all. I guess I also don't like the idea of broadcasting these few known networks I have saved.
- deleted 10y ago
  [deleted]
- bogomipz 10y ago
  >"Sending/receiving data over wifi takes roughly ~8x less power than sending/receiving data over cell" How did you arrive at this 8x figure? I don't think this is correct at all. See: http://people.cs.umass.edu/~arun/papers/TailEnder.pdf http://people.cs.umass.edu/~arun/papers/TailEnder.pdf Additionally power efficiency is related to distance from the cell tower which is generally much further away than a wifi access point.
  - kllrnohj 10y ago
    Were you misled by the changing axis scale? From that paper: > Our measurements (Section 3) confirm that the transmission energy consumed by WiFi is significantly smaller than both 3G and GSM, especially for large transfer sizes. Also that's 3G, not LTE which is what most everyone is using nowadays.
killnine 10y ago
https://f-droid.org/repository/browse/?fdid=be.uhasselt.privacypolice https://f-droid.org/repository/browse/?fdid=be.uhasselt.priv...
takeda 10y ago
This was true in the past. Now wifi off is not really off. There is an obscure setting in location where you can disable it. Of course Google does its usual, making it inconvenient. When you enable that setting wifi location is completely disabled and many apps which use finer location will trigger a popup to enable it back in order to get a better location. They do this with any setting that benefits them. For example if you don't allow Google to store your historical location Maps won't remember any locations searched. As if it was impossible to maps store that details locally sigh.
- lkbm 10y ago
  > There is an obscure setting in location where you can disable it. For those wondering, I believe the setting is Settings => Location => => Scanning (in the the vertical dots menu in the upper right) => Wi-Fi scanning (on my Nexus 5 running Android 6.0.1, anyway.)

by comboy 10y ago

anexprogrammer 10y ago

There's another wifi setting, in advanced I think, for "scanning always available"

sly010 10y ago

Its a question of terminology. When you are passively listening to (periodic) SSID beacons, you are not transmitting anything, nor consuming any energy on your radio. One could do that even in airplane mode. It's very different from when you hit "scan" and are actively sending broadcast packets on every frequency and waiting for the wifi routers to (actively) answer. Which really only happens when you pull down the list of nearby hotspots.

mirashii 10y ago
> nor consuming any energy on your radio This simply isn't true. You'll be using power to demodulate at a minimum. You'll also be using energy to ammplify the incoming signals and a variety of other things.
- klodolph 10y ago
  Yes, this is also the reason why GPS is so power hungry--it takes a lot of power to keep a GPS radio receiver operating.
  - jsjohnst 10y ago
    Close enough for a quick reply, but it's not the "radio" using lots of power, it's the chip that's doing the signal processing. GPS signals are very weak (approximately -120dbm) and thus below the noise floor. It takes complex FFT operations that actually cause the power hungry nature to find the proverbial needle in the haystack.
    - klodolph 10y ago
      Normally, "radio" includes the amplifiers and demodulators, even if they're digital.
jhayward 10y ago
> or consuming any energy on your radio Listening is actually one of the more power-intensive things a radio does, because it tends to be active more of the time than transmitting does. For many radios power consumption is the same whether transmitting or receiving.
- omilu 10y ago
  >For many radios power consumption is the same whether transmitting or receiving This, is not right.
  - mynewtb 10y ago
    Please elaborate at least a bit.

tuxracer 10y ago

WiFi is never completely off until you disable "Scanning always available" https://i.stack.imgur.com/wcQkc.png https://i.stack.imgur.com/wcQkc.png

jasonkostempski 10y ago
I don't have that option under "Advanced Wi-Fi" but under Settings -> Location -> Scanning I have "Wi-Fi Scanning Improve location by allowing system apps and services to detect Wi-Fi networks at any time". Is that the same thing? Nexus 5X, Android 7.0
- khedoros 10y ago
  Ditto, Nexus 5, Android 6.0.1. That's how I interpreted it: as a relocation and rewording of a setting.

kllrnohj 10y ago

> I turn my wifi off to save the battery Sending/receiving data over wifi takes roughly ~8x less power than sending/receiving data over cell. If you want to save battery you need to turn off data entirely not turn off wifi. Turning off wifi ultimately costs you battery.

comboy 10y ago
Not if I'm out of range of my home wifi which is practically the only wifi I connect to. I think my phone last longer like that, but I never actually measured it, so maybe it's not worth it after all. I guess I also don't like the idea of broadcasting these few known networks I have saved.
deleted 10y ago
[deleted]
bogomipz 10y ago
>"Sending/receiving data over wifi takes roughly ~8x less power than sending/receiving data over cell" How did you arrive at this 8x figure? I don't think this is correct at all. See: http://people.cs.umass.edu/~arun/papers/TailEnder.pdf http://people.cs.umass.edu/~arun/papers/TailEnder.pdf Additionally power efficiency is related to distance from the cell tower which is generally much further away than a wifi access point.
- kllrnohj 10y ago
  Were you misled by the changing axis scale? From that paper: > Our measurements (Section 3) confirm that the transmission energy consumed by WiFi is significantly smaller than both 3G and GSM, especially for large transfer sizes. Also that's 3G, not LTE which is what most everyone is using nowadays.

killnine 10y ago

https://f-droid.org/repository/browse/?fdid=be.uhasselt.privacypolice https://f-droid.org/repository/browse/?fdid=be.uhasselt.priv...

takeda 10y ago

This was true in the past. Now wifi off is not really off. There is an obscure setting in location where you can disable it. Of course Google does its usual, making it inconvenient. When you enable that setting wifi location is completely disabled and many apps which use finer location will trigger a popup to enable it back in order to get a better location. They do this with any setting that benefits them. For example if you don't allow Google to store your historical location Maps won't remember any locations searched. As if it was impossible to maps store that details locally sigh.

lkbm 10y ago
> There is an obscure setting in location where you can disable it. For those wondering, I believe the setting is Settings => Location => => Scanning (in the the vertical dots menu in the upper right) => Wi-Fi scanning (on my Nexus 5 running Android 6.0.1, anyway.)