Bug #558
closed
Added by Hammel over 7 years ago.
Updated over 7 years ago.
Description
It became clear after the two Maker Faire events that wifi in public spaces performs much worse than at home. There are probably tricks to dealing with this, not the least of which is choosing a different channel (which we can already do).
Here is a discussion on other things that can be done to improve performance: http://7signal.com/wi-fi-learning-center/top-wi-fi-issues-and-challenges/
Many of these could be configured through the pnc app.
- Target version changed from 0.13.0 to 0.12.0
- Status changed from New to In Progress
- % Done changed from 0 to 10
- % Done changed from 10 to 40
Making progress. I've got a Cairo based display showing which channels are in use and by how many networks. Now I want to graph the signal strength. To do this I need to run this command:
$ iw dev wlan0 scan
BSS 10:6f:3f:e7:24:55(on wlp3s0) -- associated
TSF: 797749164512 usec (9d, 05:35:49)
freq: 5200
beacon interval: 100 TUs
capability: ESS Privacy (0x0011)
signal: -62.00 dBm
last seen: 82272 ms ago
Information elements from Probe Response frame:
SSID: MuseBA
Supported rates: 6.0* 9.0 12.0* 18.0 24.0* 36.0 48.0 54.0
DS Parameter set: channel 40
...
So look for the BSS in the first colmn to find a new entry. Then parse out the signal strength, SSID and channel. That's good enough to start. I can graph the signal and show the SSID with each graph.
Here is how you convert dBm to a percentage. It assumes a maximum dBm of -50, which seems about right from my laptop.
quality = 2 * (dBm + 100)
See this comment on serverfault. It mentions different dBm levels for different types of hardware. Basically, for PiBox if the dbm signal is -70 to -60 then the signal is good. So I could do a "yellow line" above which the BSS is good.
- % Done changed from 40 to 70
Graphing of wifi channels and signal strength is complete. Code is committed and pushed. Looks pretty good, actually. I select colors for the graphics using the golden ratio.
Now I need to add all 14 channels to the options menu for selecting a channel for the access point. Then I should set the default to 1, 6 or 11.
- Project changed from PiBox to pibox-network-config
- Category deleted (
09 - Testing)
- Status changed from In Progress to Closed
- % Done changed from 70 to 100
Done. All changes committed and pushed.
Closing issue.
One additional note:
I swapped out all the ModMyPi dongles with the various Panda wifi dongles and things got much better. I also moved the RPI2 away from its USB hub just a bit. Maybe that's what I really needed: better dongles and less interference from the Pi.
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