Research On Vertical Handoff Algorithm For Multi-services In Heterogeneous Wireless Networks

With the rapid development of wireless access technology, the integration of the heterogeneous wireless networks has drawn more and more attention, which will be-come the inevitable developing trend of future wireless networks. Heterogeneous wire-less network can support a variety of different types of services at the same time and guarantee multi-mode mobile terminals roaming and performing handoff in the seam-less way. The mobile terminal in heterogeneous wireless network can make anyone easily access and use a network at anytime from anywhere communicating with any other terminals. Due to different vision of the wireless network technology and diversi-ty of the services, mobility management technology has become one of key technologies in the heterogeneous wireless networks. The vertical handoff management is the core part of the mobility management, which ensures the continuity of the session during multi-mode terminals across wireless networks. Therefore, the study on vertical hand-off algorithm in heterogeneous wireless network has great theory value and realistic meaning of righteousness.Recently, lots of effort has been made to vertical handoff algorithm in heteroge-neous wireless network, but it involves different network operators, network architec-tures and bearer modes. There lies three shortcomings in vertical handoff algorithms. Firstly, the vertical handover algorithm failed to consider the profit of the network oper-ators’in the face of increasingly bandwidth resource request and the explosive growth of data traffic; Secondly, the vertical handoff algorithms failed to take into account the priorities of different services and the utilization of network resources; Thirdly, ver-tical handoff algorithms are difficult to be applied due to the high complexity of the algorithm.Considering the above three points, we propose a bandwidth reservation scheme with multiple thresholds based on large deviation principle for multiple services and a vertical handoff algorithm based on markov decision process. In this paper, the specific research contents and research results are as follows.· Among the multiple factors which affect vertical handoff, the available band-width is particularly important and it’s necessary to pay more attention to it. We propose an online dynamic bandwidth reservation scheme based on large deviation principle and the scheme can reserve bandwidth resource for different services with different priori-ties according to bandwidth request. It can guarantee to meet request of bandwidth and improve the profit of the operators.·From the perspective of the user, we put forward an new vertical handoff criteri-on, which make tradeoff handoff profit and handoff cost. The vertical handoff problem is modeled as a discrete time markov decision process, which can make the mobile terminal gain maximal profit with least number of handoff in a session. Simulation re-sults show that the proposed algorithm vertical handoff algorithm improve the resource utilization and provide high quality of service.