Technology Research, Based On Sensor Network Task Allocation

The advancements of sensor technology, MEMS, modern network and wireless communications promote the development of Wireless sensor networks (WSN) with modern significance. For WSN connects the computing world and physical world by providing services to applications and users, we regard it as the sets of tasks. In order to coordinate the whole network and efficiently perform the tasks by utilizing the available resources, the task assignment technologies in the WSN are needed.At present, the study of task assignment technologies is mostly focused on distributed computing area, For WSN have some new characteristics such as tight coupling to the physical world, resource constraint, large scale and dynamic conditions, the task assignment technology of WSN is different from that of traditional distributed computing network, the traditional task assignment models and algorithms are not fit for WSN directly.Based on the application of battlefield surveillance systems and NSFC project of "Research on task assignment policies and implementation mechanisms in wireless sensor network", this thesis focuses on the research of WSN task assignment technologies. The main contents include:1. The description of task graph. The capability of task description affects the complexity of task assignment system, most description methods at present can't show the hierarchies of WSN and neglects the nature language using in task description, this paper describes the hierarchical tasks in WSN from a new viewpoint and parses the task described in nature language using semantic analysis.2. The selection of working nodes in WSN. Nodes selection makes some nodes perform tasks and others go to sleep to prolong the whole network lifetime. This paper makes some improvements to GB selection algorithm to be more effective.3. Task assignment. Task assignment mapped subtasks to nodes , the characteristics of WSN make it to be challenge. This paper proposes the hierarchical task assignment viewpoint and implements it using GaSA algorithm. The result shows that the final task assignment scheme makes the whole communications cost to be minimum.At last, an application example of battlefield surveillance system was designed.In summary, our task assignment algorithm can be applied to large wireless sensor networks, Along with the current research projects, we encourage more insight into the problems and more development in solutions to the open research issues as described in the paper.