This is absolutely correct. I don&#x27;t know the inner workings of the modulation scheme selection but suspect that the downshift is solely based on the ratio of received to unreceived acks from the client -- without knowing the reason for the non-receipt. As far as I know, the wifi standard does not contain any provision for the client device to report its received signal level to the AP. The signal levels you typically see in the AP are the levels that the AP is hearing the client at.<p>Some access points allow you to lock the modulation at a certain rate -- if you know for a fact all of the clients will be able to receive the signal at the required level for that modulation scheme, you can increase your overall effective capacity. Unfortunately this is not usually the case. We almost never get to control the client devices and positions, and without that control, received signal levels can&#x27;t be effectively predicted.