An Sdn-Based Technique For Reducing Handoff Times In Wifi Networks

The handoff process in WiFi networks has a very important role to provide continuity of the service to wireless users where the access points (APs) are in numerous numbers. In traditional WiFi networks, the handoff process takes a few seconds and is initiated by the wireless devices, but these few seconds could be a reason for information loss when dealing with delay sensitive applications. In this paper, we propose a reduced detection and discovery time approach (DeRy), which generates a solution based on software defined WiFi networks (SD-WiFi). A simple network management protocol (SNMP) manager and received signal strength indicator (RSSI) manager are employed to report the AP traffic conditions and RSSI values to the SDN controller and instead of the wireless devices, the handoff decisions are taken at the controller end. When to initiate the handoff (detection phase) and which destination AP to associate to (discovery phase) are handled by the centralized SDN controller. To implement DeRy, extensive simulation runs are carried out on Mininet-NS3-WiFi network simulator. The simulation results show that the DeRy significantly reduces the handoff times by 60-70% and reduces the average number of retransmission by 4-49%, hence maintaining the throughput for delay sensitive applications such as VoIP, when compared to the standard RSSI-based handoff scheme, channel measurement based access selection scheme (CMAS) and (DL-SINR) downlink-signal to interference plus noise ratio AP selection scheme (DASA).