Research On Coverage Control Algorithm Considering Energy Optimization For Mobile Wireless Sensor Networks

The researches for wireless sensor networks (WSNs) mainly involve the problems such as coverage control, topology control, network routing, node localization, time synchronization and energy efficiency. Among them, the coverage control is not only directly related with network monitoring quality, but also has an important effect on the following protocol or algorithm designs, making it as the basic problem in WSNs design. Currently, coverage control algorithms for the static WSNs have been relatively mature, while there are few coverage control algorithms fit for the mobile WSNs. So, the research about coverage control problem for the mobile WSNs is conducted in this thesis.Firstly, since although the existing area coverage control algorithm for the mobile WSNs can achieve a relatively high network coverage rate under the premise of ensuring full network connectivity after the initial network deployment, the movement and communication energy consumption, as well as the network coverage rate, can still be further optimized. Moreover, the algorithm ignores the backbone node dying during the network operation, which will cause rapid network connectivity rate decrease and severe influence on network reliability. Therefore, an area coverage control based on dynamic tree (ACCBDT) algorithm is originally proposed in this thesis. First, to ensure full network connectivity, the Sink node is chosen as the root node to extend the network out level by level, making the whole network topology changed into a tree topology; Second, the locations of the non-backbone nodes are adjusted to improve the network coverage rate; During the network operation, if a node is dying because of energy exhaustion, the nearest non-backbone node is commanded to help it to slow the network connectivity and reliability degradation. Simulation results show that compared with the typical mobile WSNs area coverage control algorithm, the proposed ACCBDT algorithm can not only ensure full network connectivity after initial network deployment, but also further optimize the movement and communication energy consumption, as well as the network coverage rate; Moreover, the proposed algorithm can slow the network connectivity and reliability degradation.Secondly, since although the existing target coverage control algorithm for the mobile WSNs can improve the network connectivity rate, it ignores the real node sensing energy consumption, and cannot optimize the network coverage rate, amount and balance of energy consumption. Therefore, a target coverage control based on energy-balanced clustering (TCCBEC) algorithm is proposed in this thesis. First, this algorithm considers the real node sensing energy consumption, and calculates the heterogeneous sensing ranges for nodes at different locations, which will decrease the network coverage hole; Second, the node covering the least number of targets is chosen as the cluster head node; Third, the node that makes no contribution to covering the targets is commanded to be sleepy as the helper for its nearest dying nodes. Simulation results show that compared with the typical mobile WSNs target coverage control algorithm, the proposed TCCBEC algorithm can not only decrease the network coverage hole and increase the network coverage rate effectively, but also decrease the network energy consumption amount and improve the network energy consumption balance, thus delaying the initial network reconstruction time and prolonging the network lifetime.