Research On The Hierarchy Topology Control Algorithm Of The Wireless Sensor Networks

Topology Control is a key technology of Wireless Sensor Network (WSN). The topology control algorithms can not only improve the network structure but also provide the basic platform for the algorithms of the other network layers. WSN is an energy constrained network, and the topology control algorithm can construct a special network structure to improve the network lifetime as well as the energy balance of the network. Thus, some topology control algorithms are designed based on the energy constrained WSN to prolong the network lifetime as well as improve the energy balance.If the connectivity as well as the coverage is satisfied, the management of the nodes is optimized by a topology control algorithm, which adjusts the transmission power and selects the appropriate backbone nodes and deletes the redundant links. The hierarchy topology control is a very important kind of the topology control strategy, which selects the backbone nodes and divides the network into different sub-networks with different levels. The hierarchy topology makes the non-backbone nodes sleep when the nodes are not communicating. Meanwhile the backbone nodes fuse the collected data for saving energy by decreasing the number of the packet data sent to the next hops.In the clustering topology control, the maintenance of the link between any pair nodes is not needed and the network's running is based on the rounds. In every round, all nodes participate into the network reconstruction. In the process of reconstruction, the selection of the cluster head is very important, because selecting a good cluster head can be good for the nodes residual energy balance. So, a cluster head selection mechanism is designed, which is when some round is ended the cluster heads of this round predict some cluster heads of the next several rounds. The prediction is based on the node's residual energy. So, based on the prediction mechanism a topology control algorithm called CP-DCRP is proposed in the dissertation.If the powerful computation ability is permitted, the base station (BS) computes and broadcasts the network information, and the multi-hop transmission can be applied among the cluster heads, which saves a lot of energy compared with the single-hop transmission. There are many kinds of multi-hop transmissions, and the local shortest path algorithm based on the energy distance metric is adopted. Based on the ideas described above, a comprehensive improvement topology control algorithm called SCPEBMT is proposed.If the network nodes transmit the data and the multi-hop transmission is adopted, selecting the next hop node is very important. The creation of the neighbor set is a critical step of selecting the next hop. If the nodes in the neighbor set are selected well and the number of the neighbors is adequate, a lot of energy can be saved and the energy balance of the nodes in the neighbor set is very good when a node transmit data to the next hop. So, based on the neighbor set, two topology control algorithms called RNS-MCRP and NS-MCRP respectively are proposed in the dissertation.In the clustering topology, the transmission between nodes can be multi-hop transmission or single-hop transmission. But, for the right specific cluster of a specific topology control algorithm, the energy consumptions of the multi-hop transmission and the single-hop transmission can be equal to each other because of the bad multi-hop transmission. So, a topology control algorithm based on the hybrid transmission can be designed, which is based on the critical point of the energy consumption, and thus a topology control algorithm called MS-LEACH is proposed.In the hierarchy topology control, the topology control algorithm based on the backbone is an expansion of the clustering topology control. The heuristic algorithm is applied in the backbone topology control algorithm design. All the backbone nodes construct the data collection and relay backbone network, which covers all the non-backbone nodes in the network. Based on the ideas described above, a topology control algorithm called VBT-EBHRP is proposed. At the same time, MCDSA is proposed for constructing a sub-network with the approximate minimum backbone node number. In the WSN, the backbone network with the approximate minimum node number is good for decreasing the number of the packet data, the interference and the delay.Finally, a summary is written for the research work, and the innovations as well as the future work are introduced.