移動(dòng)約束群組Ad Hoc網(wǎng)絡(luò)研究.pdf

1、Dynamic routing is a crucial，yet very challenging issue in MANETs. A flat structure，imposed on networks by default，fails to yield in large scale dynamic MANETs due to communication overhead and scalability. This implies

2、a hierarchical architecture – clustering，which is vital for efficient resource utilization and load balancing in large scale dynamic networks such as Ad Hoc and sensor networks. The clustering process entails diffusion o

3、f node identities along wireless links to yield virtual homogenous sets，whose members subscribe to some rules，with the net effect of entire network decomposition into overlapping or disjoint clusters. Nodes are assigned

4、to clusters based on geographical adjacency. Frequency re-use，reduced overhead and compact clusters are some of the benefits of clustering. Yet，clustering has some cost implications that result from cluster construction

5、and maintenance. The cost functions include explicit message exchange，ripple effect，frozen period and computation round.
　　 Over twenty clustering schemes have been proposed. Empirical evidence indicates that linear

6、 clusters often generate multiple gateways and confirms circular/roundish clusters as most stable. Besides，research shows that only three geometric shapes: hexagon，triangle and square，can tessellate an infinite，two dimen

7、sional spaces(networks). Mobility-aware circular clusters have not only been contemplated，but also formed. Yet，little attention is afforded to the mobility behavior of the nodes during cluster maintenance phase，a fact th

8、at could compromise the circular cluster shape. I propose CAN-MR，a mobility-conscious and situation-specific scheme for maintaining circular clusters. My research extends the work of Basu，P. Et al，who proposed formation

9、of a circular cluster，but failed to consistently consider the mobility behavior of nodes in cluster maintenance. I dwell on uniform periodic time for all cluster nodes，which confers to them relative stationary state and

10、consigns them to circular motion. For an arbitrary node n，the propagation path defines a locus of points (radius) distance from the CH，designated as the least mobile of the cluster nodes. The location coordinates are det

11、ermined using the sine and cosine trigonometric ratios. Yet a node-executable program could also be used in guiding node positioning and movement. Instantaneous node locations are defined by equation of a circle. For suf

12、ficiently close consecutive locations，a circle is defined，yet with adequate spacing，the shape can be manipulated to a hexagon or other convenient polygons. This allows clustering to subscribe to frequency re-use equation