Model real Wi-Fi cell throughput with airtime fairness, so slow legacy clients drag the whole cell down the way they do in practice.
Wi-Fi schedules airtime, not bits, so a client at 65 Mbps occupies thirteen times the airtime of one at 866 Mbps for the same payload. Combining the rates as a harmonic mean weighted by airtime share gives the rate the cell actually achieves, and MAC overhead removes a further third of it. This is why one old handheld can halve a modern cell's throughput, and why removing 802.11b/g data rates is usually the cheapest Wi-Fi performance fix available.
Wireless Throughput
airtime-weighted rate = 1 ÷ Σ(airtime share ÷ PHY rate); usable throughput = that rate × MAC efficiency.
airtime-weighted rate = 1 ÷ Σ(airtime share ÷ PHY rate); usable throughput = that rate × MAC efficiency. Wi-Fi schedules airtime, not bits, so a client at 65 Mbps occupies thirteen times the airtime of one at 866 Mbps for the same payload. Combining the rates as a harmonic mean weighted by airtime share gives the rate the cell actually achieves, and MAC overhead removes a further third of it.
This is why one old handheld can halve a modern cell's throughput, and why removing 802.11b/g data rates is usually the cheapest Wi-Fi performance fix available.
This calculator takes 5 inputs: PHY rate of modern clients, PHY rate of slow legacy clients, Airtime share taken by slow clients, MAC efficiency after protocol overhead, Active clients in the cell. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.