On Mon, 2011-01-24 at 07:01 +0100, juuso.oikarinen@xxxxxxxxx wrote: > From: Juuso Oikarinen <juuso.oikarinen@xxxxxxxxx> > > Below, mTU is milli-TU (TU/1000). > > The passive scan channel dwell time currently used is 30-60mTU. A typical > beacon interval for AP's is 100TU. This leads to a ~30% worst-case probability > of finding an AP via passive scanning. > > For 5GHz bands for DFS frequencies passive scanning is the only scanning > option. Hence for these, the probability of finding an AP is very low. > > To fix this, increase the passive channel scan dwell times (also the early > leave value, as 5GHz channels are still typically very silent.) Use a value > of 100TU, because that covers most typical AP configurations. > > Based on testing the probability of finding an AP (100TU beacon interval) on > a single scan round are as follows (based on 100 iterations): > > dwell min/max (TU) | probability > ---------------------+------------ > 30/60 | 35% > 60/60 | 56% > 80/80 | 77% > 100/100 | 100% > > Total scan times now and after the change: > > Region | Before (s) | After (s) > -------+------------+---------- > 00 | 0.77 | 1.48 > FI | 0.95 | 2.01 > US | 0.91 | 1.76 > > Signed-off-by: Juuso Oikarinen <juuso.oikarinen@xxxxxxxxx> > --- Applied and removed the mention to milli-TUs, as agreed on IRC. Thanks Juuso! -- Cheers, Luca. -- 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
