Handoff between WiMax and WiFi networks

One of the biggest challenges of Next-generation wireless network (4G) is to integrate different wireless access technologies, each with its own characteristics, into a common IP-based core network to provide mobile user with service continuity and seamless roaming. Nowadays there are different wireless access technologies allowing users to stay “always on”, of which one of the most important is WiFi because of the range of its utilization (used in standard personal devices, like laptop, mobile devices...) to connect to the Internet. But its range is very limited, contrary to WiMax, who is a relatively new but very promising standard for wireless communication because it provides the speed of WiFi and the coverage of UMTS (Universal Mobile Telecommunications System). Hence it is natural to combine WiMax and WiFi and create a better wireless solution to provide high speed Internet for mobile users. Currently, the mobility of a terminal is a requirement of great importance, supported by a procedure known as handover. One of the major issues for the converged heterogeneous networks is providing a seamless handover with QoS support.