Research On Topology Control Algorithm For Interference Reduction In Ad Hoc Networks

Limited resources, as well as wireless communications and node mobility make the performance of Ad Hoc network closely related to its topology. Unreasonable network topology will increase network interference, lead to decoding failure, and result in bad network performance. Hence, topology control is an effective measure of great significance to reduce the network interference and improve the overall performance of Ad Hoc networks.A topology control algorithm was proposed for reducing network interference, which is designed from network level and node level respectively. On the premise that the network is connectivity, network level topology control algorithm can remove redundant links effectively and reduce network interference. In accordance with the local characteristics of network operation, the topology control algorithm first calculates the probability that a local network is disconnected based on the required connectivity ratio of the network. Then identify the redundancy that matches each local network, which is the basis of topology control algorithm, according to the maximum node moving speed, link disconnection and the disconnection of local network. The MIMO technology is adopted in node level topology control algorithm. To improve the decoding probability of receiver, the entire network is divided into several sub-topologies. The original topology is transformed into interference topology in order to express interference distinctly. The elements are selected to add to each sub-topology, according to the requirements of limiting weak interference, controlling strong interference and communications that block each other. The sub-topologies are activated in different time period in the algorithm.The network simulation software NS2 was used to evaluate the proposed topology control algorithm. Simulation results demonstrate the algorithm can remove redundant links effectively, guarantee high decoding probability, reduce network interference and improve performance of Ad Hoc networks significantly.