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    机会网络中的自适应喷雾路由及其性能评估

    Performance Evaluation of Adaptive Spray Routing for Opportunistic Networks

    • 摘要: 针对传统喷雾路由无法适应动态网络环境的问题,提出了一类自适应喷雾路由机制.由具备最新网络知识的中间转发节点实时地进行喷雾决策,达到对网络环境的快速感知和适应,并在特定的喷雾方式下,以最低的路由代价满足目标时延约束.对提出的3种不同的喷雾机制从路由代价、副本冗余度以及期望延迟3个方面给出了理论上的分析.仿真评估结果表明,自适应喷雾路由具备路由代价低、自适应能力强、扩展性佳等特点,所提出的喷雾机制各有特点和应用场景,是一类正确有效的时延约束机会路由协议.

       

      Abstract: Opportunistic networks are sparse wireless networks where most of the time there does not exist complete path from the source to the destination. The messages can be forwarded to destination ultimately in the manner of asynchronous transmission which relies on the contact opportunities between nodes in opportunistic networks. This characteristics of opportunistic networks can greatly extend the space-time metric of information collection and processing. Although opportunistic network often shows large delay, it doesnt mean that it is not necessary to implement quality assurance. For examples, electronic notice in campus networks and short-term weather information in large national parks must be forwarded with specific delay. On the other hand, as the access networks, configuration and forecast for QoS are also necessary in order to provide acceptable service (such as e-mail) in opportunistic networks. Hence opportunistic networks must provide acceptable and resilient service in the face of challenging environments. According to the shortcoming of traditional spray routing in dynamic opportunistic networks, a class of adaptive spray mechanisms are proposed in this paper. Adaptive spray mechanisms use relay nodes to make spray decisions in order to apperceive and react to the change of network conditions exquisitely, and are least-cost delay-bounded routing protocols under specific spray mechanisms. Theoretic analysis of adaptive spray routing at aspects of routing cost, copy redundancy and expected delay are also given. Simulation results show that adaptive spray mechanisms show prominent superiority in routing cost, adaptability and expansibility, and are a class of correct and efficient delay-bounded opportunistic networks routing mechanisms.

       

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