On Thu, Jun 2, 2011 at 4:49 PM, Felix Fietkau <nbd@xxxxxxxxxxx> wrote: > On 2011-06-03 12:36 AM, Luis R. Rodriguez wrote: >> >> On Thu, May 26, 2011 at 5:59 PM, Luis R. Rodriguez<mcgrof@xxxxxxxxx> >> Âwrote: >>> >>> Â What I'd like to do is to affect the ratio to nullify it if the noise >>> Â is very low on the channel. Given that noise is logarithmic we'd have >>> Â to use a logarithmic function as well. Working on that now. >> >> OK I've figured a way to plug the noise into this, I designed the >> following function we can use as a factor: >> >> 1.1^(x+110) >> >> Wolfram|Alpha boring details of this function: >> >> http://bit.ly/mJNXE9 >> >> x,y results of different noise values in dBm, using apcalc: >> >> mcgrof@tux ~ $ calc >> C-style arbitrary precision calculator (version 2.12.3.3) >> Calc is open software. For license details type: Âhelp copyright >> [Type "exit" to exit, or "help" for help.] >> >> ; define f(x) = 1.1^(x+110) >> f(x) defined >> >> ; f(-130) >> Â Â Â Â~0.14864362802414368640 >> ; f(-120) >> Â Â Â Â~0.38554328942953174736 >> ; f(-119) >> Â Â Â Â~0.42409761837248492210 >> ; f(-118) >> Â Â Â Â~0.46650738020973341431 >> ; f(-117) >> Â Â Â Â~0.51315811823070675574 >> ; f(-116) >> Â Â Â Â~0.56447393005377743132 >> ; f(-115) >> Â Â Â Â~0.62092132305915517445 >> ; f(-114) >> Â Â Â Â~0.68301345536507069189 >> ; f(-113) >> Â Â Â Â~0.75131480090157776108 >> ; f(-112) >> Â Â Â Â~0.82644628099173553719 >> ; f(-111) >> Â Â Â Â~0.90909090909090909091 >> ; f(-110) >> Â Â Â Â1 >> ; f(-109) >> Â Â Â Â1.1 >> ; f(-108) >> Â Â Â Â1.21 >> ; f(-107) >> Â Â Â Â1.331 >> >> So then, we'd use a frequency for initiating beaconing (AP, Mesh, P2P) >> which uses the lowest value from the following computation: >> >> (busy time - tx time) / (active time - tx time) * 1.1^(noise + 110) >> >> The 1.1 factor can be modified more accurately to represent the >> exponential factor of how noise should affect interference decisions, >> the 110 value here can be modified for any other arbitrary value we >> find as representative of a regular noise value from a simple AP on >> the frequency we are observing, my assumption here was -110 dBm. > > -110 dBm is not a real noise value. It's an unrealistic, ath9k-specific > value. I have a patch that changes ath9k to make noise and signal strength > values more realistic, and I'll submit it soon, as soon as I've made it a > bit more precise. Nice. As I noted though this value is arbitrary for now, we can change it at will. Any other feedback? If not I'll start hacking on it. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
