Research On Key Technologies Of Coverage And Route For Wireless Sensor Networks

With the development of semiconductor technology, micro system technology, communications technology, computer technology and distributed signal processing technology, a new information collected network-wireless sensor networks (Wireless Sensor Networks, WSNs) is proposed and paid more attentions. Sensor nodes can monitor and collect the environment information. By composing the multi-hop and self-organization routing, sensor nodes can send the sample data from monitor area to the sink node. Wireless sensor networks are widely applied in national defense, security, environmental monitor and health care fields.Due to the special characteristics, various requirements and limitation of network performances in WSNs, routing protocol of WSNs differs from that in traditional wireless networks. In this thesis, several key factors about routing protocol designation are investigated significantly including energy efficiency, multi-sinks problem and maximum network lifetime. Coverage control technology affects the routing protocol designation of WSNs. The efficient routing models, path planning models and reliable communication also are related with the coverage control technology. In this work, a multi-hop routing protocol and coverage control scheme are studied deeply. Main research fruits are summarized as follows:(1) The mathematical model and simulation experiment prove sensor nodes distributed with Poisson characteristics and quantified the perception of nodes deployed the radius, the density and area of coverage, the relationship of k-coverage, and the coverage control model. In the premise of ensuring the effective covering area of monitoring for node to obtain the number of dormancy nodes approximately, which provide a reference for the experiments of sensor node random distribution and researches about the nodes deployment and control reference problems, according to the different area coverage, using local node coverage in communication method, and the radius of perception radius, full consideration under different conditions of coverage of complex overlapping node, the minimum coverage strategy, appropriate maximum nodes appear empty allows active coverage, still can reach at least nodes are very close to the setting of the coverage.(2) Data collected by many sensors is based on common phenomena, and hence there is a high probability that this data has some redundancy. It is expected that communication approaches that take into account this redundancy. We present a maximum lifetime data aggregation routing scheme and address the problem of jointly optimizing data aggregation and routing so that the network lifetime can be maximized. Establish the relationship model between data aggregation rate and throughput, so that the balanced was set up between the data aggregation rate and maximum network lifetime. Through the use of optimal candidate sample allocation, the algorithm can coverage efficiently and can make the maximum data aggregation rate flow to the network while maximizing network lifetime.(3) We present a maximum lifetime and maximum flow routing scheme in the article. We address the problem of jointly data aggregation and routing protocol, so that the network lifetime and flow can be maximized simultaneously. Based on the maximum flow and minimum cut theorem, there exists a feasible solution to deal with the network maximum flow. We developed an approximation algorithm for constructing a data aggregation tree. The algorithm proposed in the paper tries to reduce the normalized load of the heavily loaded nodes by partially rearranging the link to create a new tree. Our algorithm tries to make improvements until no improvement can be made to heavily loaded nodes. Our purpose is to create a maximum data flow to the network while maximizing network lifetime.(4) In wireless sensor networks, a sink node usually gathers data from all battery-powered sensor nodes. As sensor nodes around the sink node always consume their energy faster than other nodes far away the sink node, several sinks can be deployed in monitor area to increase the network lifetime. Anycast is a transmission mechanism that a source node sends the data to the nearest sink node. We study and design an anycast service scheme for deploying several sinks simultaneously in wireless sensor network. A novel anycast based on tree-structure is proposed to minimize the path cost. Here, several nodes and one sink node form a tree with the sink node as the tree root. Multiple metrics is integrated to calculate path cost based on diverse selection criteria. The model is discussed and analyzed deeply in the paper.(5) In large-scale sensor networks, Anycast is an effective mechanism that a source node always sends the data to the nearest sink node. My work extends the anycast mechanism and designs a k-anycast service for deploying several sinks in wireless sensor networks. Several sinks can form an anycast group which completes tasks cooperatively. A k-anycast group based on tree structure is proposed to enhance the transmission reliability and reduce the E2E delay. Here, several nodes form a tree with a sink node as the tree root. The source node constructs at most k paths reaching one anycast group, which contains at most k sinks when data is transmitted from the source node. In this paper, the model about a k-anycast service is discussed and analyzed deeply. The experimental results prove its validity and efficiency.