A Hybrid Channel Scan Mechanism for Improved VoIP Handoff Performance in 802.11 WLANs

Seamless handoffs with Quality of Service (QoS) guarantee play a decisive role in the provision of realtime applications such as Voice over Internet Protocol (VoIP) over IEEE 802.11 networks. During a handoff process, a channel scan needs to be first performed in order to discover new Access Points (APs), and it can be done by either passively listening to beacon signals or actively exchanging probe messages with new APs. The authors have previously presented a channel scan algorithm, in which voice activity is taken into consideration and beacon listening is scheduled only during silent periods of a VoIP conversation.