How to fine-tune the wireless link with hw-retries?
You should understand that for 802.11 devices there is really limited amount of information (or “feedback” from the environment) that devices can use to tune their behavior: • signal strength, which could be used to figure out best transmit rate knowing receiver sensitivity. Sill this is not reliable taking into account that sensitivity for different receivers varies (e.g. changes over time), path conditions are not symmetric (and device can only measure signal strength it receives), etc. • by receiving/not receiving acknowledgment for frame sent. Taking into account that using signal strength is not reliable, 802.11 device is essentially left with only one “feedback” to tune its operation – success/failure of transmission. When transmission fails (ACK not received in time), there is no way how sender can figure out why it failed – either because of noise, multipath, direct interference (and wether that disturbed actual data frame or the ACK itself) – frame just did not make it and in
