A Low Delay Topology Control Algorithm Based On Delivery Ratio Constraint In Wireless Sensor Networks

The sensor nodes have limited energy which is supplied by battery, so that the primary objective of wireless sensor network is to maximize the network life. Because the wireless sensor network is an application-related network, the performance requirements in different application scenarios are usually different. For example, this paper aims at the emergent application scenarios, such as the earthquake or fire rescue. In this case, the maximum network life is not the primary goal because it would be meaningless to search and rescue after a certain time. In contrast, the high delivery rate and low delay of data packets should be the key goals during the effective rescue and rescue period. The topology control as the core supporting technologies of wireless sensor network not only can improve the efficiency of routing protocol and MAC protocol, but also can provide the infrastructure for the data fusion, time synchronization and target localization, and thus a good topology can effectively optimize the network performance.In order to achieve the high delivery ratio and low delay, a low delay topology control algorithm(LDBDC) based on delivery rate constraint is proposed. The algorithm can approximately compute the optimal average hop count of a given region according to the given delivery ratio to obtain the size of the virtual hexagonal grids. Then, the monitor area is divided into some layered grids, which elects cluster heads through a cluster head election algorithm. Especially, he cluster head is responsible for forwarding the data to the adjacent inner grid. The simulation experiments indicate that LDBDC can obtain the approximate optimal topology structure, and achieve the minimum average delay under the constraint of delivery ratio.At the end of this paper, a simple ZigBee multi-hop communication system is realized based on hardware nodes, and then the software demo system of LDBDC algorithm is implemented on the basis of the multi-hop communication system. The software demo system can calculate the optimal size of the virtual hexagonal grids according to the different parameter settings, and can display the regional grid graph to shape a distribution map, which is mapped into a dynamic topology. Afterwards, LDBDC algorithm is formed to count the average delivery ratio and delay for analysis.