Advanced seamless vertical handoff architecture for WiMAX and WiFi heterogeneous networks with QoS guarantees

The development of wireless networks brings people great convenience. More state-of-the-art communication protocols of wireless networks are getting mature. People attach more importance to the connections between heterogeneous wireless networks as well as the transparency of transmission quality guarantees. In this paper, WiFi wireless networks and WiMAX mobile communication system are selected as our research subjects. VHTC (Vertical Handoff Translation Center Architecture) is proposed to improve the transmission QoS guarantees. Thus, the quality of transmission cannot be reduced enormously even by the effect of vertical handoff between heterogeneous wireless networks. This paper includes new approaches and architecture among Packet Translation, QoS Mapping, Bandwidth Borrowing Management and Vertical Handoff Protocol with a view to achieve the goal, that is, an advanced seamless heterogeneous wireless networks. Also, through the modification of WiFi module of TKN and WiMAX module of NIST, these two heterogeneous wireless networks can be connected and embedded in NS2 (Network Simulator version 2) simulation system. Afterwards, the methods, proposed in this paper, can be implemented in such simulation system. Finally, lots of satisfactory simulation results about throughput, delay, jitter and packet loss rate were given to show the brilliant performance of vertical handoff implemented by VHTC.