Abstract
This thesis develops the performance analysis of Herogeneous Intersystem Mobility in large scale networks by using computer simulation. HIM is a roaming mechanism to achieve intersystem roaming between IPv4 and IPv6 in heterogeneous wireless networks including 3GPP, 3GPP2, and WLAN networks. It not only enables users to use high data transmission rate and large service coverage but also provides users with the ability of maintaining communications sessions even after roaming. This thesis presents detailed performance evaluation of HIM in large scale networks.