Research And Development On Handover Technology In Heterogeneous Wireless Network

In the past decade, there has been a remarkable growth in the use of wireless and mobile communications. Although various wireless access network technologies with different characteristics and performance level have been developed, no single network that can satisfy the anytime, anywhere, and any service wireless access needs of mobile users. The next-generation wireless networking is envisioned as a convergence of various wireless access technologies. One of the major design issues in heterogeneous wireless networks is the support of vertical handoff. IEEE has introduced a standard on vertical handover known as Media Independent Handover (IEEE 802.21 MIH) which aims to achieve end user mobility by assisting the vertical handover across heterogeneous wireless technologies thus improving end user experience. However, the current MIH standard lacks context-aware architecture which is needed to adapt to the changing network dynamics and mechanisms to distribute load uniformly in the network. Vertical handover decision algorithm is the most important part in handover technology. However, with the increasing number of inputting parameters, handover algorithm system will be more complicated and can’t satisfy the quality of service for mobile users. So the main contribution of this thesis can be summarized as follow:(1) In this thesis, we propose an enhanced architecture to IEEE 802.21 Media Independent Handover (MIH) framework called context aware MIH (CA-MIH). In the CA-MIH framework, we add in two new components known as parameters monitor and events monitor for handling both local and remote dynamics information and vary events. And we also offer an information updating algorithm for period measurement all the information. The thesis design a new trigger mechanism which can handle more events from different level and trigger handover actions.(2) The thesis proposing a novel handover algorithm based on Fuzzy Logic (FL) pre-decision and Technique Order Preference by Similarity to an Ideal Solution (TOPSIS) method, which can adapt to the dynamic network condition and reduce the system load, is applied to the All-IP heterogeneous network for vertical handover. And it is combined with the forward difference prediction for the signal strength of next time to improve the handover accuracy. The results of simulations indicate that the proposed algorithm can make accurate handoff decision and show better performance in terms of evaluation metrics. Enhance the application service qualify and user experience after the process of vertical handover.