• Juuso Oikarinen's avatar
    wl12xx: Increase scan channel dwell time for passive scans · ea45b2cb
    Juuso Oikarinen authored
    The passive scan channel dwell time currently used is 30-60TU. 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: default avatarJuuso Oikarinen <juuso.oikarinen@nokia.com>
    Reviewed-by: default avatarLuciano Coelho <coelho@ti.com>
    Signed-off-by: default avatarLuciano Coelho <coelho@ti.com>
    ea45b2cb
conf.h 23.6 KB