移动Ad Hoc网络中保证覆盖的准确计时可靠链路方法  

Coverage-Ensured Reliable Links with Accurate Timing in Mobile Ad Hoc Network

作　　者：张治国[1] 刘聪[1] 张鹏[2] 

机构地区：[1]中山大学信息科学与技术学院,广东广州510275 [2]中山大学数学与计算科学学院,广东广州510275

出　　处：《软件学报》2007年第7期1765-1773,共9页Journal of Software

摘　　要：在移动AdHoc网络(mobile ad hoc networks,简称MANETs)中,由于节点的快速移动,网络的物理拓扑结构在不断地变化.各个节点由于不能及时获得网络物理拓扑结构的更新,基于自我剪枝的广播算法难以获得有效的连通支配节点集,而不能保证广播信息的覆盖.为了保证广播信息的覆盖,在自我剪枝的广播算法中考虑链路的有效时间.假设广播存在节点覆盖范围不同和“Hello”信息周期长度不同,并且各节点按各自的方向和速度不断移动的网络,则节点的相对速度和广播半径决定了节点间连通的有效时间.依据链路中各节点的准确计时信息可以获得链路有效时间,从而为每个节点提供肯定有效的网络拓扑结构信息.称其为准确计时的可靠链路方法(reliable links with accurate timing,简称RELAT).利用准确计时的可靠链路方法,可以保证移动Ad Hoc网络广播中的虚拟网络连通性和物理链路的有效性,并基本上保证了本地视图的一致性,使得可以有效地保证广播的覆盖.大量的模拟实验数据表明,RELAT算法能够有效地保证覆盖,且当网络的密度较大时,即使放宽其中的一些条件仍能保持较高的覆盖率.In practical Mobile Ad-Hoc NETworks （MANETs）, the network topology changes while the nodes move quickly. Each node cannot ensure the broadcasting coverage to all other nodes because it cannot update its information on the network topology instantly. This is because the self-pruning based broadcasting can not calculate a valid connected dominating set promptly in the quickly moving environment. For ensuring the broadcasting coverage in MANETs, the period of validity for routing links is taken into account. It is supposed that each node in the network has different transmission ranges, different ＂Hello＂ intervals, and moves in different directions and at different velocities. The period of validity of connection can be determined according to the relative speed and the transmission ranges of the nodes. The accurate timing in each node for counting the period of validity of the connection is used to provide the correct and instant information about the network topology. This method is called the Reliable Links with Accurate Timing （RELAT）. RELAT guarantees the conditions of connectivity of the virtual network and the availability of the physical links, and in the most cases the consistency of the local view so that it ensures the broadcasting coverage in the network, Simulation results show that this algorithm is sufficient to ensure the broadcasting coverage in MANET and it also has high probabilities of coverage in the case of high node density even the conditions for the algorithm are not fully satisfied.

关 键 词：无线移动网络 广播 保证覆盖 准确计时的可靠链路 传送节点集 模拟 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]