【作者】 孙玉婷；

【导师】 郭忠文；

【作者基本信息】 中国海洋大学 ， 计算机应用技术， 2009， 博士

【摘要】 水下无线传感器网络的节能问题一直是近年来大家研究的热点,涌现出了不少与数据处理相关的组网协议技术和研究成果。目前,水下无线传感器网络主要利用水声进行通信,网络节点依靠声波来传递信息,水声换能器成为必不可少的部件。由于柱形换能器可以做成水平无指向性、垂直指向性可控的宽带换能器,是声纳系统中仅次于纵向换能器的一种类型,因此更适合在浅海中使用。本文研究一种适用于柱形换能器的无线传感器网络组网协议,建立网络理论分析模型,提出适用于水下无线传感器网络的数据传输控制方法,并针对给出的网络部署模型对其MAC层协议进行研究,提出新的路由传输机制和节点定位方法,通过仿真验证其有效性。论文的主要研究内容包括：1、抽象基于换能器的水下节点,建立水下节点的通讯模型,定义节点的部署概率和换能器概率,给出两节点间连通概率的计算公式,并通过仿真研究换能器基本参数与节点连通概率之间的关系,从而得出换能器发射角是影响换能器概率的主要因素。本文提出了适用于水下稀疏部署的固定部署模型,对于给定区域,给出节点部署密度与节点通讯概率之间的关系；对于水下节点的随机稠密部署,给出了节点部署密度与节点通讯概率之间的关系。2、在结合第一部分给出的连通概率的基础上,针对水下网络特点,提出适应此网络模型的MAC协议算法。第一种方法是根据节点连通概率确定节点之间发包重传次数,在此基础上采用RTS/CTS机制进行通信建立；第二种方法是进一步考虑降低节点能量消耗,确定合理的休眠机制,最后通过仿真验证了算法的有效性。3、针对本文提出的固定部署和随机部署,分别给出了基于固定部署和随机部署的路由转发协议。对于固定部署,基于最短路径的原则,建立从源节点到目的节点多条路径来实现能量的平衡。为了提高路由算法的自适应性,当路径上有节点损坏时,通过寻找损坏节点附近的新的节点来替代损坏节点以保持路径的有效性,从而提高了路由的可靠性和网络的吞吐量,并通过仿真验证了其有效性。对于随机部署,考虑节点间的连通概率、节点的剩余能量以及与目标节点之间的距离等因素,给出了转发节点的选择依据,从而减少节点的盲目转发,同时每个节点通过维护转发节点排除表来减少选择邻居节点时的计算量,通过仿真显示该协议可以使得网络能量平稳下降,有效的延长网络的生命周期。4、定位部分利用了声波幅度的有关特性和第一部分连通概率与距离的关系,分别提出了一种测距方法,并应用到定位方法中。第一种方法是利用了声波在水下传播时幅度衰减和距离的关系,进而推导出一个有关距离和幅度的公式,然后利用三边定位的方法进行定位；第二种方法使用移动节点依据了节点的连通概率来推算出两节点之间的距离,定位时也采用三边定位的方法确定未知节点位置,最后通过实验和仿真验证了这些定位方法的适用性。更多还原

【Abstract】 Energy saving is one of the hottest research topics in recent years for underwater wireless sensor networks there has been a lot of network technology and research results related to data processing. Now, the sound is the main communication medium in the underwater wireless sensor network (UWSN), so the underwater acoustic transducer is a requisite component in the underwater acoustic system. The cylinder transducer can be unlimited-horizon and controlled-vertical,so it is the one which is second to the vertical transducer in the sonar system, which is more widely used in the shallow sea.In this paper, we present one network protocol which can be used in the UWSN with the cylinder transducer, build the network analysis model, bring forward the control method used in the UWSN’s data transmission, propose the MAC protocol of the given network model and put forward the new route transmission mechanism and node-orientation method, at last we test the validity. The main research contents are as follows:1.We build the communication model with cylinder transducer nodes, define the deployment probability and the transducer probability, deduce the formula which calculates the connection probability between the nodes, and via the relation between the basic parameters of the transducer and the node connection probability, then we conclude that the launch angle of the transducer is the main factor which affects the transducer probability. In this paper, we bring forward a fixed-sparse deployment model used in underwater WSN. For the given area, we can make the curve of the relation between the nodes deployment density and the communication probability through the simulation. For the random dense underwater nodes deployment, we can make the curve too.2.Based on the connection probability mentioned above and the characteristics of the UWSN, we bring forward the MAC protocol algorithms which matche the network model.The first algorithm introduces the connection probability into the RTS/CTS mechanism to build the connection between the nodes;the second one uses the sleep-wake mechanism to cut down the energy-cost, at last we test them through the simulation.3.We respectively propose the route protocols for the fixed-deployment and random-deployment situation. As for the fixed-deployment, we use the shortest-route role and build multiple paths from the source node to the destination node for the balance of energy. To improve the self-adaptability of the route algorithm, we substitute the bad node with the new one nearby when the node is destroyed and it can keep the validity of the route, improve the dependability of the route, increase the throughput of the network. As for the random-deployment, we give the choosing principle of the transmitting node to avoid the blind-transition by the way of each node maintaining the table of the excluded transmitting-node and cutting down the calculated amount when it chooses the neighbor nodes thinking of the node connection probability, the remaining energy,the distance between nodes and so on. At last we show that this protocol can lower the network energy steadily then lengthen the network lifetime through the simulation.4. In this part of the orientation, via the characteristic of the sound wave amplitude and the relation between the connection probability and the distance, we respectively bring forward a position-setting method. The first one uses the relation between the range-decay and distance, then bring forward the formula to calculate the distance. At last we locate the unknown node with trilateral position method. The second one is that we use mobile node and the node connection probability to calculate the distance between the two nodes, we still use trilateral position method to locate the unknown node’s position. We test and confirm them through the simulation in the end.更多还原