On Tuesday, July 26, 2011 08:21:21 PM Luis R. Rodriguez wrote: > On Mon, Jul 25, 2011 at 7:46 PM, MingAnn Ng <devil_eddie01@xxxxxxxxxxx> wrote: > > Hi Luis, > > > > this is what I'd got after applying logarithm identities patch that you > > provide: > > > > 2412 MHz: -175.357726 > > 2417 MHz: -inf > > 2422 MHz: -inf > > 2427 MHz: -inf > > 2432 MHz: -inf > > 2437 MHz: -inf > > 2442 MHz: -inf > > 2447 MHz: -inf > > 2452 MHz: -inf > > 2457 MHz: -inf > > 2462 MHz: -inf > > 2467 MHz: -inf > > 2472 MHz: -inf > > 5180 MHz: -187.707255 > > 5200 MHz: -186.721397 > > 5220 MHz: -186.067982 > > 5240 MHz: -186.584516 > > 5260 MHz: -186.872511 > > 5280 MHz: -184.567340 > > 5300 MHz: -185.224387 > > 5320 MHz: -185.794143 > > 5500 MHz: -189.525424 > > 5520 MHz: -189.417120 > > 5540 MHz: -189.705191 > > 5560 MHz: -189.639734 > > 5580 MHz: -190.396324 > > 5600 MHz: -189.503429 > > 5620 MHz: -189.685961 > > 5640 MHz: -189.421184 > > 5660 MHz: -189.814113 > > 5680 MHz: -190.737770 > > 5700 MHz: -190.546318 > > Ideal freq: 2417 MHz > > Hm, as for the new values -- they look very different from what you > had gotten before so the math went wrong somewhere.. gotta revise that > a bit more carefully. well, take a close look at the patch. > - factor *= (base_to_power(2, survey->noise - min_noise)); > + factor += survey->noise + min_noise; In the original version, you substracted the min band noise from the channel. Whereas now you add them together. > > The result is almost the same as the version before applying the patch. the > > -inf still fall on those channel. and those channel are indeed very busy in > > my lab. Is there any other solution which I can try to get a better result > > out of it? > > > > I haven't try on the latest patch for hostapd which you uploaded. Is the acs > > application work along with hostapd to calculate the interference level? > > No, the ACS implementation on hostapd simply uses the internal code > from hostapd so its much easier to write, the acs.git code is > completely independent so adding anything there is just a bit harder, > for example adding a scan prior to the ACS work. Please do try the > hostapd patches to see if you get a good channel, and enable debugging > to see the values you get. We do want to avoid the -inf stuff > completely. Getting that means our data type is not sufficient for our > data. The difficult aspect of this code is that the values range from > fractional values to extremely large values.. well, if you do a [active] scan. channel_time_tx + channel_time_busy will definetly not be "zero". Maybe we can get away by adding some threshold cuts-offs. At least this would fix the -inf. + factor = log2(max(1, survey->channel_time_busy - survey->channel_time_tx)); + factor -= log2(max(1, survey->channel_time - survey->channel_time_tx)); [However, we could also ignore channel surveys with result in a -inf] Regards, Chr -- 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
