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.