When designing for voice over WLAN, what is the recommended cell overlap percentage between adjacent APs?

10% overlap is too small for voice traffic - by the time the client has enough overlap signal to initiate a roam, the current AP signal may already be too weak, causing call drops.

A 20% overlap guarantees that a VoWLAN client always has a strong signal from a neighboring AP before it disconnects from the current one, preventing audio gaps. This overlap threshold is the industry standard recommended in Cisco VoWLAN design guides and ensures roaming triggers occur while signal quality is still sufficient to maintain the call.

15% overlap is sometimes cited for general data WLANs but does not provide enough redundant coverage margin to support the low-latency handoff requirements of voice.

30% overlap is excessive and increases co-channel interference between APs, which degrades overall WLAN throughput and voice quality rather than improving it.