Mobility management in heterogeneous wireless networks based on IEEE 802.21 framework

Wireless and mobile networks are evolving very rapidly. The mobile nodes in the wireless networks are having multiple interfaces with different radio access technologies (RATs) which are having different capabilities, cost and performance ratio. The use of non-PC based portable devices is increasing due to their flexible usage. The wireless and mobile network which is formed by these non-PC and PC based devices is heterogeneous in nature and these networks are co-located. Multiple interfaces can be included in the mobile device by using separate hardware and software modules. A mobile user wants to be Always Best Connected (ABC) as per its various requirements and availability in a particular environment. When a mobile node leaves the current network and joins the other network, a handover operation is needed and performed. The Handover operation is used to achieve seamless mobility and is of two types, first is in between same RATs and second is in between different RATs. For seamless and smooth handover operations across heterogeneous networks, IEEE has published a standard, named as IEEE 802.21. This paper presents a comprehensive description on the issues and challenges for achieving the seamless mobility in a heterogeneous environment. Apart from this, we also present the description of services provided by IEEE 802.21 standard and related vertical handover schemes to realize seamless mobility in heterogeneous network.