ACS seems not to select the best channel in 2.4GHz.

[Fumikazu Yobimoto]

Hi,

> I'm not sure skipping the adjacent channels completely on 2.4 GHz would
> be ideal solution here. It is clear that the channels at each end of the
> band will require something more accurate. It may also be reasonable to
> at least drop the importance of the impact from adjacent channels.

I understood that's reasonable, agreed your idea.
I tried to test ACS using your latest patch, and I was able to see a good
result
as I hoped. In addition, I tested other value witch Eduard mentioned.

#define ACS_ADJ_WEIGHT 0.85
#define ACS_NEXT_ADJ_WEIGHT 0.55

The experiment result shows it works fine. I attach on the bottom.


-An error about patch-
It seems having one mistake. is the part of adding adjacent value of +10MHz.

                                adj_chan = acs_find_chan(iface, chan->freq +
                                                         (j * 20) + 10);
-                               if (adj_chan && acs_usable_chan(adj_chan))
-                                       factor +=
adj_chan->interference_factor;
+                               if (adj_chan && acs_usable_chan(adj_chan)) {
+                                       factor += ACS_NEXT_ADJ_WEIGHT +
            <= This line.
+
 adj_chan->interference_factor;
+                                       total_weight += ACS_NEXT_ADJ_WEIGHT;
+                               }

it should be

+                                       factor += ACS_NEXT_ADJ_WEIGHT *
+
 adj_chan->interference_factor;



==== result
set sample value to each channel interference factor.
1  =0.78
2  =0.764
3  =0.743
4  =0.729
5  =0.366
6  =0.158
7  =0.404
8  =0.613
9  =0.601
10 =0.585
11 =0.63


Try to get the ideal channel changing weight definition.

1.
ACS_ADJ_WEIGHT=0.5
ACS_NEXT_ADJ_WEIGHT=0.25
ACS_24GHZ_PREFER_1_6_11=0.8
channel 1: total interference=0.770143, total_weight=1.75
channel 2: total interference=0.759, total_weight=2.25
channel 3: total interference=0.7104, total_weight=2.5
channel 4: total interference=0.6056, total_weight=2.5
channel 5: total interference=0.4385, total_weight=2.5
channel 6: total interference=0.3514, total_weight=2.5
channel 7: total interference=0.4125, total_weight=2.5
channel 8: total interference=0.5205, total_weight=2.5
channel 9: total interference=0.5834, total_weight=2.5
channel 10: total interference=0.601667, total_weight=2.25
channel 11: total interference=0.613, total_weight=1.75

2.
ACS_ADJ_WEIGHT=0.85
ACS_NEXT_ADJ_WEIGHT=0.55
ACS_24GHZ_PREFER_1_6_11=0.8
channel 1: total interference=0.765854, total_weight=2.4
channel 2: total interference=0.756769, total_weight=3.25
channel 3: total interference=0.695355, total_weight=3.8
channel 4: total interference=0.573355, total_weight=3.8
channel 5: total interference=0.460737, total_weight=3.8
channel 6: total interference=0.408053, total_weight=3.8
channel 7: total interference=0.418737, total_weight=3.8
channel 8: total interference=0.493658, total_weight=3.8
channel 9: total interference=0.575789, total_weight=3.8
channel 10: total interference=0.605692, total_weight=3.25
channel 11: total interference=0.607417, total_weight=2.4

Thanks,
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