Radio signals grow weaker as the distance between the transmitter and receiver increases. Meanwhile, the data rate for a given client will adjust dynamically depending on the distance and signal strength. As the distance between AP and client increases, the signal strength will decrease. As the signal strength decreases, the current data rate cannot be maintained. The transmitting device will drop its data rate to the next rate in order to maintain the connection. In some cases, you may not want the AP to throttle down to lower data rates in order to support higher bandwidth applications. Most AP’s allow you to configure the data rates supported based on the 802.11 standard.
Modern WiFi analysis tools like the AirCheck® G2 and EtherScope® nXG provide insight into the signal strength and data rates being achieved at various locations within your environment