【作者】 刘建金；

【导师】 谭长庚；

【作者基本信息】 中南大学 ， 计算机应用技术， 2008， 硕士

【摘要】 无线自组网的拓扑对网络性能有很大的影响,密度高的拓扑会因干扰的加大而降低容量,稀疏的拓扑又会因为链路失效和网络分割而导致网络不连通。拓扑控制的目的就是优化网络的性能,同时减少节点的能量消耗。由于无线自组网的拓扑是动态变化的,故要求拓扑控制算法不仅能在初始时建立具有某种性质的网络拓扑结构,而且在拓扑发生变化后,算法能够重构网络,保障网络的连通性,并且以较小的开销维护网络已有的属性。本文主要分析了现有的拓扑控制算法存在的两个问题:维护周期固定不变和未考虑环境变化的因素。针对这两个问题分别提出了维护周期自适应变化的拓扑控制算法VPLMA(Varying Periods Local MeanAlgorithm)和自适应环境变化的拓扑控制算法EATCA(EnvironmentAdaptive Topology Control Algorithm)。VPLMA算法是对LMA算法进行改进,采用动态变化的维护周期的方法来维护网络的拓扑结构保持其连通性。EATCA算法是通过预测节点周围环境的变化,自适应调整节点的发射功率以保证网络拓扑的稳定,从而保证网络的性能不受影响。最后通过仿真实验验证了本文提出的算法的有效性。仿真结果表明采用维护周期自适应变化的拓扑控制算法VPLMA,能保证在数据发送成功率和端到端延迟基本不变的情况下,使能量消耗减少10%左右。采用自适应环境变化的拓扑控制算法EATCA能降低30%左右的端到端的延迟,提高10%左右数据发送成功率。更多还原

【Abstract】 The topology of wireless ad hoc network has a significant impact on its performance in that a dense topology may induce high interference and low capacity, while a sparse topology may induce link failure and network partitioning. Topology control aims to maintain a topology that optimizes network performance while minimizing energy consumption. Owing to the topology of the wireless ad hoc network is dynamic, the topology control algorithm not only should establish a network topology which has some characters in the initial time, but also can reconstruct the network topology when it changed. This is important for the wireless network to ensure connectivity and the existing properties in low cost.This thesis analyze two problems of the present topology control algorithms. Considering the two problems, this thesis proposes two algorithms, named VPLMA and EATCA. The VPLMA algorithm is designed based on LMA algorithm, and it maintains network topology by alterable period.In EATCA algorithm, network nodes can predict the environmental change, then it adjusts transmitting power to ensure the stability of network topology, thus ensuring network performance.Finally, this thesis verify the effectiveness of the two algorithms through simulation. The results show that the VPLMA algorithm can reduce energy consumption by 10%, while it guarantees packet delivery ratio and end to end delay unchanged. And the EATCA algorithm can reduce end-to-end delay by 30% and increase packet delivery ratio by 10%.更多还原