Research On Distributed Topology Control Algorithm In Ad Hoc Networks Based Directional Antenna

Ad hoc network is self-organized without any immobile basic communication facilities, whose characteristics are wirelessness, multi-hop and mobility. In Ad hoc networks, it is undesirable to have nodes transmit with maximum power for two reasons. First, since the power required transmitting between nodes quickly increases as the distance between them, it affects network spatial reuse and decreases the network lifetime. Second, the greater the power with which a node transmits, the greater the likelihood of the transmission interfering with other transmissions, which results in excessive interference, reducing traffic carrying capacity; On the other hand, while choosing too small a power level, it may result in a disconnected network because of the bottleneck node's failure. It is the main topic for the researches about topology control to find good algorithms to reduce the consumption of the node's transmitting power, so as to mitigate network collisions, improve traffic carrying capacity and save nodes'energy consumption.By establishing the algorithm simulator and building network performance platform of topology control, we have compared the structure characteristics and influence on network performances of topology, which is generated by several classical topology control algorithms, discover that the interference between nodes is an important factor which impacts network transmission performances. Accordingly, a distributed topology control algorithm based on directional antenna with strong anti-interference is advanced. The main research work and contributions are as follows:Summarize the characteristics of Ad hoc networks and analyze several classical topology control algorithms, which elicit the important factor interfering the structure performances of topology is nodes'density distribution and transmission range. Discover that the topology generated by the topology control algorithms should be possessed of less nodes'degree and transmission range.Advance a distributed topology control algorithm-K-DABTC (K value-Distributed Topology Control Algorithm for Ad Hoc Networks Using Directional Antennas), which is based on directional antenna with strong anti-interference. The strong connected and undirected characteristics of generated topology are proved, and the algorithm, which possesses the characteristics of distribution, sparse and the degree of edge node bounded, only needs collect local information. Experimental results show that the proposed algorithm significantly reduces transmission power of 12% of average power, and improve network performancesreduce, the routing overhead.Build network performance platform of topology control and analyse influence on network performance for different algorithms by EMA(External Module Access) interface of networks simulation tool-OPNET. Simulation results show the effectiveness of topology control algorithms.