distance setting in gui?

[eramseth]

I've been able to get better real-world throughput over a wireless-n bridge by manually setting the max distance on my AP and my STA by logging in over SSH and setting:

Code: Select all

uci set wireless.radio0.distance=60

I believe by default this option is off or set to 0. I also believe this really controls the ACK timing of the wifi radio. On atheros radios I believe the default is to auto-adapt based on real-world data.

The openwrt wiki says the setting should be set based on maximum distance between the AP and the furthest client (in meters). The range of settings is pretty big. I think it can go from 1-999999.

I found this info on the dd-wrt wiki and I believe it applies here as well:

Sensitivity Range
Adjusts the ACK timing in Atheros typical way based on the maximum distance in meters:

0 disables ACK timing completely
1 - 999999 adjusts ACK timing
The default is 2000 meters.

When a packet is sent out from the router, it waits for an "ACKnowledgement" frame from the other end. The router will wait for a response until a certain amount of time has elapsed, called the "ACK timeout" (or "window").

Conventional wisdom holds that should be set to the maximum distance in meters x 2 (doubled to account for round-trip). For example, if you roam with your laptop up to 50 meters from your AP, the setting would be 100.

Under nominal conditions (obstructions, power limitations, in-band interference, etc), the usable range of 802.11b/g is perhaps less than 100 meters, so it might seem that this setting should never exceed 200. However, if using a directional antenna that boosts range, timing needs would increase. Maximum theoretical ACK timeouts are approximately 744µs (11 km) for 802.11b, and 372µs (55 km) for 802.11g. There have been reports of experimental, assisted WiFi connections in excess of 40 kilometers plus.

Another use for ACK might be for restricting the distance at which people can connect. This could be useful for WDS access points or for minimizing the zone of connectivity.

Keep in mind, the higher the ACK timing, the lower the throughput will be. If set too high, packets could be lost as the router waits for the ACK window to timeout. Conversely, if ACK is set too low, the window will expire too soon and returning packets could be dropped, also lowering throughput.

While I don't mind changing this setting over SSH, I think it wuld be useful to allow it to be set through the web GUI, as it can lead to noticeable throughput improvement when set correctly.

[genix]

Try this patch for 1.5 branch
Actual option name can be changed to dd-wrt-like "Sensitivity Range" or "ACK Timing"
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Edit: changed option name to 'Sensitivity Range' and fixed small visibility bug