Research On Handover Scheme Of Wireless Multihop Network

In recent years, as the user demands for wireless networks grow, many technologies for different kinds of wireless networks developed rapidly. As a promising network architecture, wireless multi-hop network is a non-center,self-organization and quickly expand network. Wireless multi-hop network increasingly becoming a hot research topic. Different from the traditional Wireless Local Area LAN(WLAN) with point to multipoint architecture. Wireless multi-hop network have many advantages, such as it can efficiently enhance the coverage area of broadband wireless access netwwork, improve the transmission links quality, low initial investments and so on. These give wireless multi-hop network a wider application prospect.However, due to the appearance of new service and the increase of user demand, the convergence of multimedia communications and wireless mobile network presents new challenges for management of mobility,such as network entrance and seamless end-to-end communications, etc. The core issue among them is the management of handover, which is aim to guarantee the Quality of Service(QoS). The handover algorithms employed in a wireless multi-hop network have a significant impact on overall network performance. The management of handover contains MAC layer's handover scheme and IP layer'handover scheme. During the handover process, the handover decision algorithm will be applied to decide whether the handover should be executed, which cell or network is the new candidate and how to correctly route packets to their destination, etc.This paper firstly analyzed IP layer's handover mechanism which proposed by IETF in detail, and then specifically described the MAC layer's handover process of 802.16e. From the analysis of the two schemes, we can see that even though there are fully defined procedures in the two layers, it couldn't reach the requirement of seamless.Therefore, in order to reach seamless handover performance, this thesis analyzes the reason why causes so much handover delay, makes optimization on it, and proposes a handover scheme based on cross-layer technology. Compared with other similar schemes,the scheme validates its pretty low handover latency and disruption time.In order to enhance the mobility management performance, we couldn't only focus on research into cross layer's handover.Therefore this article not only research on cross level handover flow, but also has carried on the comprehensive introduction of the network coding's elementary theory. The author made a deep research on wireless network coding, and proposed a wireless network coding scheme in wireless multi-hop network whose feasibility is proved at the same time. This new wireless network coding scheme can not only accomplish the upper bound of network capacity, but also greatly reduce the resource consume of-wireless networks. The most important function of this scheme is that can make MS get neighborhood information effectively, reduce the outage probability, ensure service continuity, improve the QoS of cell edge, optimize the whole handover system.