Research Of Network Lifetime Prolonging Algorithms For Wireless Sensor Networks

Wireless Sensor Networks(WSNs),which are made by the convergence of sensor,micro-electro-mechanism system and network technologies,is a novel technology about acquiring and processing information and can be used to transfer information to the terminal users.They are widely used in military and civil applications in terrestrial,underwater,underground and many other fields.Wireless sensor networks mainly use wireless radio,acoustic communication technology and so on.Wireless sensor networks usually operate in an unattended environment with limited energy.The battery can not be recharged.Therefore,minimizing energy consumption and prolonging the network lifetime are key requirements in the design of sensor network protocols and algorithms.This paper focuses on lifetime prolonging strategies for terrestrial WSNs and UnderWater Sensor Networks(UWSNs).The main content of this paper is divided into five parts.●This paper introduces an optimum radio range,considering the balance between the transmission energy consumption and the receiving energy consumption to minimize the energy consumption in multi-hop communication. A sub-optimal distance based multi-hop routing algorithm is proposed,in which the relay is selected randomly in a local circle.Thus,the sensor nodes near the optimum radio range are selected as the relays.An optimum transmission range is also presented to prolong the network lifetime for UWSNs.This study is based on the different definitions of the network lifetime and the character of underwater acoustic sensor.Therefore,it provides not only a gauge for performance evaluation of UWSNs but also a guideline for the design of UWSNs protocols.Simulations show that the algorithm can save more energy and prolong the network lifetime.●Unbalanced energy consumption influences greatly the network lifetime. Therefore,this paper introduces hybrid transmission mechanism for cell-based wireless sensor networks.The sensor node forwards data either by one-hop direct transmission or by multiple small hops.This mechanism focuses on a novel transmission probabilities finding algorithm.The algorithm can obtained the hybrid transmission probabilities of each slice to even out the energy consumption efficiently.Furthermore,lateral length optimizing method is developed for each cell.Simulations show the mechanism can prolong the network lifetime more efficiently comparing with other schemes.Because the cell-based network induces the problem that the real transmission distance has very big difference with the theoretical transmission distance,the energy is not balanced efficiently.This research divides the network model into some annuluses,and improves the above methods.A probability based energy balance algorithm is proposed.The sensor node transmits data by hybrid transmission.This scheme focuses on transmission probabilities finding algorithm,in which the transmission probabilities for each slice are obtained to even out the energy consumption efficiently.In order to optimize energy consumption,further,a sub-optimal distance based energy optimization algorithm is introduced.It optimizes the slice width and selects relays by sub-optimal distance near the optimum radio range,saves more energy and improves the network lifetime efficiently.Our claims are well supported by simulation results in comparative performance evaluation.●This paper analyzes a hybrid data transmission mechanism based on energy level to balance energy consumption and prolong lifetime in UWSNs.The mechanism combines one hop and multi-hop data transmission to underwater sink by considering the current energy level of adjacent nodes.An optimal classification number of energy level has been evaluated through theoretical analysis.The simulation results of UWSN's lifetime and the energy consumption of sensor nodes have proved the efficiency of the proposed mechanism.●Limited bandwidth capacity and battery power are the unique characters of UWSNs.This study introduces a competition scheme based on delay time. This scheme provides a selection method of relay nodes considering the limited bandwidth capacity.Then a heterogeneous nodes distribution strategy is proposed to balance the energy consumption of the whole UWSN.The ratio of the node's initial energies of the adjacent annuluses is analyzed in a circular UWSN.●The concept of Data Aggregation Rate(DAR) is introduced to denote the compressing capability of a sensor node in the sensor networks.The traditional assumption conditions about sensor capabilities include Perfect Data Aggregation(PDA) and No Data Aggregation(NDA).DAR breaks through the traditional assumption conditions and presents a new assumption.Furthermore, the traditional assumptions can be considered as two special cases of the new assumption.Then,a relationship among DAR,lifetime and the amount of the signal received at the base station is given.Simulations show that the proposed assumption is more efficient.