Research On Localization Algorithm Based On Virtual Force In Wireless Sensor And Actor Network

Wireless Sensor and Actor Network(WSAN) is derived from Wireless Sensor Network(WSN),which consists of couples of sensor nodes and actor nodes.Actor nodes are resource-rich and equipped with powerful process ability,which are capable of processing the data gathered from sensor nodes and making proper decisions and actions.To some extent,WSAN is a type of new network,which can change the physical world.So WSAN makes more demands for the important localization technology. In additional,existing WSN localization algorithms can’t be transplanted into WSAN.For the drawbacks of traditional WSN localization algorithms and combined with requirements of WSAN,WSAN localization algorithms are researched in this paper.The main research areas are as follows:1. Domestic and overseas research progress of WSN/WSAN localization algorithms are summarized, and the reasons why existing WSN localization algorithms can’t be used in WSAN are analyzed.On the basis of WSN,a comprehensive introduction of WSAN is made from the aspect of architecture,node types,network characteristics and so on.Meanwhile six common classification methods are listed,and the representative algorithms are discussed in details.2. Mobile Range-free Localization Algorithm based on Square Area(MRFS) is proposed.MRFS uses mobile actors instead of anchors to locate sensor nodes.First,the area of the unknown node is determined through the actors’ square deployment;secondly,this area decreases through iteration;finally,the centroid of this area is calculated and treated as coordinate of the unknown node.Using mobile actors can effectively save deployment cost of the network.Moreover,compared with range-based technology,range-free algorithms greatly reduce hardware cost.Simulation experiments show that MRFS achieves good performance.To avoid too close or sparse density of actors in local area and to make free actors well-distributed,virtual force is introduced while positioning,so MRFS Localization Algorithm based on Virtual Force(MRFSVF) is proposed.Simulation experiments prove that introduction of virtual force can effectively improve actors’ distribution,optimize the coverage,and decrease localization error and time.3. From aspect of range-based localization,Time of Arrival(TOA) localization algorithm calculates propagation time of the signal between two nodes to estimate the distance.Here TOA is combined with virtual force. Actors move under the action of virtual force,which makes them move close to the sensor node that sends location request,thus improving location success rate.Performance of the algorithm is verified through simulation experiments.4. For characteristics and applied occasions of these localization algorithms, applications of the algorithms are introduced.