Optimal Architecture in Hierarchical Mobile IP-based Wireless Access Networks

摘要

During recent years there has been a continuous increase in traffic load over wireless networks. The next generation of mobile networks must grow to handle the increase in demand in IP traffic. Micro mobility management and provisioning of Quality of Service (QoS) have become two main factors for the successful deployment of the next generation of IP based mobile communication networks. Hierarchical Mobile IPv6 (HMIPv6) protocol has become prominent for providing micro mobility to these networks. Deployment of Mobility Anchor Points (MAPs) in conventional HMIPv6 introduces two main drawbacks in HMIPv6based access networks. Firstly, they are points of bandwidth contention within the access networks. Secondly, Mobile Nodes (MNs) generate excessive handover signalling overhead as a result of ping-pong movement between ARs of different MAP domains.In this thesis, a novel network architecture in HMIPv6 access networks is proposed to enhance the network performance in terms of both drawbacks mentioned above. In the proposed topology, each AR is assigned to more than one MAP by forming overlapped regions between MAP domains.Numerical and simulation analysis are carried out to quantify the impact of the new architecture on the handover signaling overhead, MAP congestion level, packet delay andnetwork throughput. Linear programmes are formulated to optimise the throughput andcongestion in access networks. The results illustrate that when MAP domains are overlapped, the lightly loaded MAPs will provide their residual capacities to the ARs located in the heavily loaded MAP domains. Overlapped regions are optimally configured between MAPs in order to minimise the handover signaling overhead. The results indicate that the gain can be considerably increased by deploying the proposed MAP selection mechanism. Three heuristic algorithms were proposed to dynamically adapt to network changes such as traffic and MN’s mobility characteristics. The simulation results show that all three proposed algorithms outperform Sanchis’ non-overlapping partitioning algorithm. A Dynamic QoS aware multi-MAP registration algorithm is proposed so that individual MNs can select a MAP according to their QoS requirement and level of handover support.In all this, the thesis provides a structured framework for the analysis and optimal configuration of overlapping MAP domains within a HMIPv6 based access network. This can enable the next generation of IP mobile networks to efficiently manage the huge volumes of IP traffic that are expected in the future.