Keep track of the average RSSI using an Exponential Moving Average (EMA).
Use it to dynamically tune radio receive sensitivity.
The idea is simple:
- increase sensitivity when the RSSI is bad to optimize throughput on
long distance to the AP, and
- decrease sensitivity when the RSSI is good to reduce noise level and
optimize throughput on short distance to the AP
The EMA allows to smooth RSSI variations so we don't end up changing the
sensitivity too frequently. We check if it would be worth updating the
sensitivity every one second.
RSSI thresholds were taken from the Ralink Tech. Linux driver.
from FreeBSD/OpenBSD that supersedes ral*.[ch].
Not yet enabled because I don't have a CardBus controller to test and it
will most likely crash during detach.
I tried to include our modifications, but if something is missing please
tell me or add it.
Special thanks to minipci.biz for the donation of one PCI RT2661 and
one CardBus RT2661.
