A Pre-Scanning Fast Handoff Scheme for VoIP in WLANs
IEEE 802.11 Wireless Local Area Networks (WLANs) have been widely deployed, and many applications are implemented on WLAN. As one of the interesting wireless services, wireless Voice over Internet Protocol (VoIP) can provide low-cost real-time voice service to mobile users. But the IEEE 802.11 wireless network cannot satisfy the QoS of VoIP. The delay during handoff process can last up to 1 second. Applications with delay restraint like VoIP will drop the call when the delay is more than 50 ms. Therefore this paper analyzed the delay made by the handoff process, and proposed a pre-scanning fast handoff scheme.