Research On Topology Control Algorithm For Ad Hoc Networks Using Beam Directional Antennas

With the rapid development of communication technology, embedded computing technology and sensor technology, Ad Hoc networks, as a new type of wireless network communication mode, have become one of the main academia research focuses in recent years. The characteristics of stochastic laid, self-organization and adaptation to the environment have promoted the process of free communications in any environment, and have provided effective solutions for military communications, disaster relief, interim communications, etc.In Ad Hoc networks, network nodes are mostly small volume embedded equipments can only take battery as the source of energy and usually exist in the complicated and dangerous geographic areas; and the battery of nodes can't be replaced or recharged. If all nodes work with the maximum transmit power, the limited energy of the nodes will be depleted quickly by communications components, which will affect the quality of wireless communications and lower the network life cycle. At the same time, the wireless signals of every node in the network will cover other large number of nodes, which will make the wireless signals conflict very frequently and lower the network throughput. Besides, a large number of edges existed in the generated network topology make the amount of network topology information large and make the routing calculation complicated. How to balance the node energy consumption effectively and lower the interference between nodes is one of the key issues in Ad Hoc network research.Topology control technology is the important part of Ad Hoc network. In the premise of ensuring network connectivity, topology control technology forms optimized topology through adjusting the transmit power of nodes and building appropriate adjacent relationship to extend the network life cycle and improve the network throughput. The main works of the thesis are as follows:(1) Analyse several existing classical topology control algorithms and get some simulators of them.the result shows that the alogorithms reduce the average node'degree and transmission range,which can improved the capacity of economizing on energy and the capacity of anti-jamming.(2) Advance a topology control algorithm-SLTC(Steered beam directional antenna based Local optimal Topology Control algorithm) for local optimization based on the steered beam directional antennas according to the advantages of energy conservation and resistance to interference of the steered beam directional antennas. To build SLTC algorithm performance simulation platform through OPNET network simulation tools and analyze various loads, the network throughput of diverse topologies generated by different topology control algorithm and the parameters of average end-to-end delay and routing overhead, etc. The results of simulation experiments show that the proposed algorithm has reduced the average node'degree and transmission range, boosted the capacity of network throughput,reduced the delay and routing overhead.(3) Control the dissipative of node energy based on the SLTC algorithm. The main aim of the algorithm is to balance network energy, which has considered the circumstance of node energy imbalance in the network. To extend the network life cycle through selecting the node with the largest residual energy as the arehead and apperceiving the change of neighbors'energy periodically to rebuild the network topology and balance network energy.the result shows that the new algorithm reduces the number of the dead node.