The Research Of Wsn Topology Control Based On Multi-layer Mechanism

The topology control technology of wireless sensor network has important theoretical and practical values. It can be divided into two directions: power-based topology control and multi-layer topology control. Multi-layer topology control mechanism divides the sensor nodes into clusters, and makes some cluster head nodes active to perform the network management and data transfer tasks. This paper's work is based on several basic algorithms and the contributions include:1. LEACH algorithm, GAF algorithm and TopDisc algorithm are compared in this paper. LEACH algorithm is discussed and its performance still can be improved in some way. In GAF algorithm, the time consumed by selecting cluster head can be reduced. In TopDisc algorithm, the remaining energy of sensor nodes is not considered and can be take into account when optimizing.2. As for LEACH algorithm, in order to optimize the delay time and network bandwidth efficiency under certain application circumstances, Improved STM communication mechanism is introduced. Performance analysis proves its better communication performance under certain application circumstances.3. In this paper the GAF algorithm and GAF-FULL algorithm are discussed. In order to improve the time consumed when selecting cluster heads, Improved GAF-FULL algorithm is introduced. In Improved GAF-FULL algorithm, the nodes in one virtual grid are first divided into several sub-groups, the most power-left node in each sub-group is picked out, and then the final cluster head is selected from the winners of sub-group. Performance analysis proves its effectiveness.4. In this paper the TopDisc algorithm is discussed. Because TopDisc algorithm does not take into account the remaining power of each node, an improved algorithm, named Power-balanced TopDisc is presented. In Power-balanced TopDisc algorithm, the nodes with less energy will not be selected as cluster heads so that the lifetime of the whole network can be prolonged and the total energy can be consumed balanced. Simulation tests are made to prove its effectiveness.