Research On Hole Plastic Scheme Based On Node Position In WSN

Geographic routing has been considered as an efficient and simple routingprotocol, which is very much in line with the resources limited and low-costcharacteristics of wireless sensor network (WSN). Node in WSN to obtain its positionby node localization algorithm is the premise of the geographic routing since itforwarding data based on the node location information. In addition, geographicrouting faced with the problem of empty detour. The so-called void area is part of thesensor network where is not covered by the sensor nodes due to uneven distribution ofnodes, the obstacle, node premature death and other factors. When packets wereforwarded to the void boundary, detour strategy must be taken to bypass the void.Existing node localization algorithm often exploits the location information ofanchor nodes to calculate the position of nodes to be positioned. However, to obtainthe location information, anchor nodes need to equip with GPS which is veryexpensive, and the application of this method is limited in environment such as thebottom of the sea, cave, indoor where the GPS information cannot be accepted. For theabove reasons, that is, to get rid of the limit of anchor nodes, a novel locating methodwithout anchor node is proposed. The existing ways to address the void in networkoften take bypass method. In this kind of method, the bypass method is implementedwhen the packet arrives at the concave area of the hole and this result in additionalrouting detour overhead. To address this problem, a hole plastic scheme is proposed inthis thesis. The basic idea of this method is that on the premise of knowing the nodeposition information, nodes in the WSN judges whether it is a stuck node according tothe position information of itself and the neighbors’. And the node labeling process isthe concave area filling process, and finally the concave area is filled with stuck nodes.In this way, the packet changed its way before arrive at the edge of the concave areawhich bring a better bypass path. The main innovation of this thesis as follows:1. Propose the improved ABC positioning algorithm. This algorithm is a kind oflocating algorithm without using anchor nodes and it includes three steps: first, create local coordinates using the method in ABC with three power nodes; second, locatenodes which are located in the public communication range of power nodes; finally,select some anchor nodes whose local coordinates have been known. These nodes areused to iterative calculate the coordinate of nodes in the network respectively in thediffusion way of ABC algorithm. Simulation results show that the algorithm has highpositioning accuracy and good robustness, and thus it has important significance inpractical applications.2. Propose the FTHSP (the fill type of hole plastic scheme) algorithm. The basicidea of this algorithm is that nodes in the network marked itself according to thecoordinate information of itself and the neighbors. Nodes in the concave area markeditself as stuck nodes. Unless the source or destination node locates in the concave area,the stuck nodes will not participate in data transmission. This method can prevent thepacket be sent into the concave area effectively, thus reducing the detour routingoverhead.