Joint Admission Control and Vertical Handoff between WLAN and WIMAX in Wireless Mesh Networks for QoS

With the integration of various wireless access networks, wireless networks will be dominant in the next generation. The multi-hop wireless access network, wireless mesh-network (WMN) is a promising wireless technology for several emerging commercial applications, where nodes can act both as a host as well as a router. The integration of various wireless networks into one common network is possible by heterogeneous wireless network (HWN). The HWN requires more complex and intelligent RRM (Radio Resource management) techniques which will enable the coordination among the different radio access technologies. Joint Admission Control (JAC) is a new common RRM mechanism that handles all new or handoff service requests in the HWN. The proposed vertical handoff scheme aims at reducing handoff signaling overhead on the wireless backbone and providing a low handoff delay to mobile nodes. Unlined handoffs in this hybrid network have become an increasingly important issue. In this paper we have presented an interworking architecture of wireless mesh backbone and proposed an effective vertical handoff scheme between 802.11 and 802.16. The handoff decision algorithm combined with admission control can guarantee quality-of-support (QoS) support to the existing traffic flows in WLAN and WIMAX by transferring new calls to the other network whenever necessary, so as to provide QoS support to as many users as possible. Simulation results demonstrate that the newly proposed vertical handoff scheme performs well with respect to system throughput and end to end delay.