802.21-Assisted Distributed Mobility Management Solution in Vehicular Networks

Recently, distributed mobility management (DMM) solutions have been proposed to address the drawbacks of centralized mobility management (CMM) solutions. The Internet engineering task force (IETF) has stated that extending and reusing CMM protocols are one of the considerations for DMM solutions design, where it is less faulty and more effective. Therefore, IETF has proposed a network-based DMM solution based on the well-known network-based CMM protocol: Proxy Mobile IPv6 (PMIPv6). However, network-based DMM has marginal improvements over the handover latency and packet loss of PMIPv6. Thus, this paper enhances the handover procedure of network-based DMM using the HO-initiate process and the IEEE 802.21 media-independent handover services. We tackle the issue of binding registration latency by performing the HO-initiate process proactively. Moreover, we mitigate the latency of discovering next access network and candidate mobile anchor access routers (MAARs) with the support of the lower three layers' information of the mobile user and surrounded MAARs. A neighbors network information container is introduced to store and retrieve the link and network layers' information of neighboring networks. A candidate access networks cache is defined at the serving-MAAR to decrease the prediction time. Furthermore, we propose a candidate access network selector to facilitate smart handover decision making by using the information of required and available resources in the candidate networks. We derive an analytical expression to evaluate the proposed solution compared with DMM and fast handover for DMM mechanisms. Simulation is also performed to verify the analytical results, where we consider realistic urban and highway environments. Numerical and simulation results prove that the proposed solution decreases 74.61% of the overall handover latency in DMM.