【作者】 罗娟；

【导师】 唐文胜；

【作者基本信息】 湖南师范大学 ， 计算机软件与理论， 2008， 硕士

【摘要】 无线传感器网络作为新兴的网络测控技术,是能够自主实现数据采集、融合和传输应用的智能网络应用系统。无线传感器网络使逻辑上的信息世界与真实的物理世界紧密结合,从而真正实现“无处不在的计算”模式。无线传感器网络无论是在国防,还是在国民经济的各个领域均有着广阔的应用前景。在本课题的研究与实验过程中,参考了大量的中英文参考文献,学习了现有的拥塞控制算法,并对其进行了归纳,对各拥塞控制算法进入了比较深入的研究。阐述了现有拥塞控制算法的主要思想,优点以及不足之处。本文的主要创新工作在以下两个方面:(1)在现有拥塞缓解方法的基础上提出了一种自适应的无线传感器网络拥塞缓解机制,主要思想是每个节点包含一个邻居节点信息表,其中包括唯一的标识号ID、节点的拥塞度、剩余能量,当某个节点发生拥塞以后,首先通过节点信息表找到满足条件的节点建立新路径,如果新路径建立成功,则拥塞可以得到一定程度的缓解;如果建立新路径失败,引入公平汇聚机制,按汇聚数据流权重大小比例限制上游节点速率以减少源节点数据发送率,最终达到缓解拥塞的目的。实验证明该机制有效的提高了能量利用率,降低了丢包率,使重要数据能实时地传到sink节点。(2)根据拥塞控制中公平性问题,提出了基于联合信息熵拥塞公平性控制算法(EFRS)。主要思想是当节点发生拥塞时,节点按上游节点联合信息熵值的大小计算权重,按权值用令牌桶算法限制上游节点流量,分配带宽。实验证明,它有效的实现公平的带宽分配。同时它的提高了能量利用率,降低了丢包率。最后,对全文进行了总结,并展望了以后的工作。更多还原

【Abstract】 WSN(Wireless Sensor Network) is a new network measure and management technology. It is an intelligent network application which can implement data collection, gathering and transmission by itself. WSN closely connect logically information world with genuine physical world, so as to implementing the "compute anywhere" model. WSN has expansive application foreground in national defence and every field of country economic.During the research and experiment of the task, we reference a lot of English and Chinese literatures, studied some current algorithms deeply, In this thesis, we sum up the algorithms and introduce the main method. Based on these characteristics and the limitation of current method, this thesis has done mainly the work of two as follows:(1) This thesis proposes an adaptive scheme to alleviate congestion in sensor networks. Every node has its own neighbors’ information table, which includes ID, congestion level and residual energy. It attempts to alleviate the congestion by creating more routing paths. When creating new path is failed, the thesis introduces aggregate fairness model to reduce forwarding rate in proportion to upstream link’s aggregate flow weight and to alleviate the congestion. Simulations demonstrate that the scheme can improve energy efficiencies, reduce the number of dropped packets and ensure that some important data packets can reach sink node timely and fairly.(2) According to the characteristic of WSN, we introduce a new definition of fairness and joint entropy into alleviation congestion scheme based on the current fairness. It’s called EFRS (Joint Entropy based Fair Rate alleviation Congestion Scheme). EFRS will distribute the bandwidth in proportion to the value of joint entropy, to alleviate the congestion. And the actual rate of upstream nodes will be bounded by the algorithm of token-bucket. Extensive simulations demonstrate the scheme can reduce the number of dropped packets, improve energy efficiency and make sure that the number of received data packets is in proportion to the number of useful data which are contained in the data packets.Finally, this paper summarizes all the works and views the future work.更多还原