A wireless communication system including at least one IEEE 802 multi-stack wireless transmit/receive unit (WTRU) and a plurality of technologically diversified access networks, such as IEEE 802.X networks and Third Generation Partnership Project (3GPP) networks, that are concurrently deployed. Both the multi-stack WTRU and the technologically-diversified networks include a media independent handover (MIH) function. The WTRU is configured to read MIH information transmitted from one of the IEEE 802.X networks, trigger 3GPP authentication and authorization procedures based on the MIH information, obtain a local Internet protocol (IP) address, establish a tunnel to a packet data gateway (PDG) in a 3GPP core network, construct a care of address (CoA) and register the CoA with a home agent of the WTRU, whereby data destined for the WTRU is routed via the home agent through a new tunnel established between the home agent and a foreign agent based on the CoA.