Media Independent Handovers: LAN, MAN and WAN Scenarios

A new plethora of wireless access technologies and services are emerging, driving the Internet access paradigm to a different stage. In order to provide seamless connectivity among the new wireless access technologies, such as Wi-Fi, WiMAX and UMTS, the IEEE 802.21 standard has defined the Media Independent Handover framework. This paper presents a thorough description of a seamless handover procedure in a heterogeneous access network environment, by describing the different phases of the handover process to support the interactions with Wi-Fi, WiMAX and UMTS. Further, we present a meticulous evaluation of the depicted handover mechanisms, optimized by the 802.21 framework, demonstrating that seamless mobility is achieved with low latency and no packet loss. To perform the evaluation, significant add-ons, described in this paper, were implemented in the NS-2 simulator to support all the functionalities defined by the IEEE 802.21 standard. results show that all the tested handovers, between the several technologies, are indeed seamless, with handover execution delays in the order of 100 ms. Moreover, the QoS metrics achieved are also compliant with the services requirements, with low latency and jitter and no packet loss. We conclude that fully and seamless mobility between distinct technologies and scenarios is achieved. This paper is organized as follows. Section II briefly presents related work in the inter-technology mobility area, and Section III shows how IEEE 802.21 can operate with different access technologies. Section IV describes the several handover procedures, optimized by 802.21 and integrated with the access technologies, and Section V includes the add-ons that were built to the ns-2 simulator. The scenarios and results are depicted in Section VI, and finally, Section VII concludes the paper and presents the future work.