Research On Base Station Layout And Performance Of Hybrid Multi-hop And Cellular Network

Hybrid multi-hop and cellular network is the combination of cellular network and mobile Ad hoc network; it has cellular network's reliability and mobile Ad hoc network's flexibility through dynamic configuration. Forming local sub-network, implementation of virtual cellular extension and virtual cellular splitting, these make the network has the advantage of high adaptability and intelligence. By infrastructure-based cellular network supported, it can improve the connectivity of mobile Ad hoc network, avoid lots of routing overhead and wasting bandwidth in networks, resolve the limitation of network scale, increase the reliability and quality of communication between different node; through the self-organization and multi-hop relay ability of mobile Ad hoc network, it can reduce the bottleneck effect of base station in cellular network and balance the traffic, increase spatial reuse of frequency and capacity of network, make up for the leak of network coverage, improve the flexibility of network deployment, reduce the cost of network construction and operation. Hybrid multi-hop and cellular network is an important form of 4G or future wireless mobile communication system, can provide users with on-demand multi-level services, not only to meet the needs of the existing target market, but also contains a great commercial value and social benefits with a great deal of technical and market potential.Hybrid multi-hop and cellular network deal with the combination of the two distinct networks, thus, for network performance, it is still a lack of accurate and effective evaluation and quantitative analysis. Many key technology solutions is a problems of poor universal, such as network architecture design, communications mode selection, channel assignment strategy, the design of hybrid routing protocol and so on. Based on comprehensive collection of existing research solution in and beyond the country, the thesis makes an intensive study of base station layout method and network performance for hybrid multi-hop and cellular network. The work content includes four parts as follow:1. Research on layout of base station in hybrid multi-hop and cellular network. Aim at optimized layout of base station in 2-D hybrid multi-hop and cellular network, considerate of connectivity and QoS of network, defined the evaluation functions, and presented the methods of base station layout that based on nodes distribution in network. Through analysis of characteristics in different methods of base station layout, presented methods of base station layout that based on statistical characteristics of network, and proved the efficiency by simulation results. Finally, the optimized method of base station layout for balancing the connectivity and QoS of network is proposed.2. Quantitative performance analysis of network capacity and network coverage for hybrid multi-hop and cellular network. First, in network capacity respect, the thesis presented the model of hybrid multi-hop and cellular network end-to-end capacity region, this provided a mathematical framework for describing network capacity. Based on the framework, the analytical expression of hybrid multi-hop and cellular network capacity is derived, and presented theoretical support for the best routing protocol. Second, in network coverage respect, by the thesis derived the analytical expressions of relay node achieving probability, call blocking probability and call dropping probability in two-hop access hybrid multi-hop and cellular network, at the same time, the effects of parameters on the performance of system are analyzed The simulation results shows, the hybrid multi-hop and cellular network can improve the capacity of network effectively, reduce the call blocking probability and call dropping probability, enhance the coverage of network.3. Characteristic analysis of virus spreading behavior in hybrid multi-hop and cellular network. By means of study on virus spreading in real world, based on SI model, presented three models of virus and anti-vrius spreading: SIF model, A-SI model and A-SIM model, these models effectively depict the different behavior and control method of virus spreading. Based on the graph theory, the thesis analyzed the distribution law of nodes in hybrid multi-hop and cellular network, and compared the difference in virus spreading for different network topological structure. Aim at the characteristics of mobility and multi-hop communication which hybrid multi-hop and cellular network nodes have, the impact of the speed of node and maximum number of hops on virus spreading are analyzed. At the same time, behavior of different virus spreading model are also analyzed and compared. Finally, by involved anti-virus feature in base station, the thesis analyzed the control impact on virus spreading in this environment. These researches make a better idea of virus, find out the weakness of virus spreading, accurately predicts the loss that made by virus and improves network security.4. Study on routing protocol for hybrid multi-hop and cellular network. Based on optimized link State routing protocol (OLSR), a new adaptive communication mode routing protocol ACMR for hybrid multi-hop and cellular network is proposed. By the proactive property of OLSR, node maintenance routing information in its zone through OLSR protocol, and communicates with another node within its zone directly. By use of adding new control message, node communicates with another node beyond its zone, and realizes the selection and switching of communication model. The protocol effectively reduces the overhead of network routing, improves the performance of routing, selects and switches communication model flexibly and intellectually. Besides, transfer and balance traffic are realized by registration agent mechanism. The simulation results shows, this protocol has a good usability in many aspects.