【作者】 吕宁波；

【导师】 余华；

【作者基本信息】 河南农业大学 ， 农业信息化技术， 2011， 硕士

【摘要】 无线传感器网络(Wireless Sensor Network, WSN)技术综合了微电子技术、无线通信技术、嵌入式计算技术和传感器技术四种主要技术,为实际应用中的数据信息的采集、处理和传输提供了一种全新的技术手段.无线传感器网络本身具有的环境适应性、自组织性、动态适应性、应用相关性等特点使得该技术可以满足不同领域的应用需求,大到军事领域、空间探测、辐射检测、洪灾预警、农田管理等领域的应用,小到家用电器自动化、病人病情实时监控等应用,都可以通过无线传感器网络技术来实现.目前我国农业正处于由传统向现代农业转变的关键时期,信息技术的发展和应用为其提供了革命性的推动作用,其中传感技术和智能信息处理是保证正确定量获取农业信息的重要手段,该方法弥补了以往数据监控的缺点.由于农田环境具有监测区域大、实时性要求高、环境恶劣、实验周期长等特点,对传感器节点的能量供应的持久性有较高的要求,一旦一个节点(尤其是关键节点)因能量消耗完毕不能继续工作,会影响整个农田环境监测系统监测的数据真实性。因此,对于农田环境监测系统来说,路由协议选择的关键在于怎样均衡能量开销,延长整个网络的生命周期。论文在对现有的无线传感器网络路由协议进行分析和比较的基础上,针对农田环境监测系统的实际应用,提出了基于能量均衡的路由算法,主要的研究工作和创新包括以下几个方面:(1)采用簇首轮换机制。在簇首的选择过程中,不是周期性地进行簇首的轮换,而是要着重考虑簇首节点的剩余能量,选择剩余能量一定的节点来当选簇首节点。簇首轮换机制的设定可以通过在簇建立完成后,在簇内设定一个能量阀值来实现,将当前簇首节点的剩余能量和能量阀值进行比较,如果簇首的剩余能量低于能量阀值,则开始进行簇首节点的重新选择,进行簇首轮换。只有簇内成员节点的剩余能量不低于能量阀值时,该簇内成员节点才有机会当选为簇首。如果簇首节点剩余能量高于能量阀值则不需要进行簇首轮换。(2)簇内通信采用TDMA方式。簇内传感器节点主要负责实时监测周围环境信息和将监测到的数据信息发送至簇首节点,簇内所有成员节点都将数据发送至簇首节点,而数据信息的传输只能一个接一个进行,不可同时进行数据传输,因此可以建立TDMA时隙表,为每个簇内成员节点分配不同的数据传输时隙,当簇内有数据传输发生时,其他簇成员节点可以关闭自身携带的无线收发器,以节省自身的能量消耗。(3)簇间通信采用多跳方式。考虑到农田监测区域较大,对于远离基站的簇进行数据传输时消耗能量较大,可能会导致远离基站的簇过早能量耗尽。因此,在簇首节点向基站传输数据之前应先建立簇间数据传输的路由,传输数据时由簇首节点沿着已建好的簇间路由一层一层向外传输,直到到达基站。更多还原

【Abstract】 Wireless sensor network technology integrated four main technologies: microelectronics technology, wireless communication technology, embedded computing technology and sensor technology, this technology provides a new technology for data information collection, processing and transmission in practical applications. Wireless sensor network which have characteristics suck as environmental adaptability, self-organizing, dynamic adaptability, application correlation etc, that makes this technology can satisfy the different application needs. From military field, space exploration, radiation detection, flood warning, farmland management etc field to household appliances automation, patient real-time monitoring etc field can realize through wireless sensor network technology.At present our country agriculture is in the key period of transformation from tra- ditional to modem agriculture, the development of information technology and appli- cation provides the revolutionary role for it. Thereinto, the sensing technology and intelligent information processing is important means that ensure correct quantitative gain agricultural information .This method is compensated for the shortcomings of previous data monitoring . Because of farmland environment is provided with broad monitoring area , High real-time , Bad environmental and long experimental cycle, the permanence of The sensor node power supply would be a higher requirement.If one node can’t work on due to no power,especially the pivotal node,the datas of farmland environment monitoring system would be unreal.Therefore,the key of choosing the routing-protocol is how to equilibrium the power cnsumption,in order to extend the lease of the system.This paper put forward one routing algorithm base on energy equilibrium,accrding to the practical application of farmland environment monitoring system,on the basis of Analysis and comparison of the existing wireless sensor network routing protocol.The primary researches and innovation linculding the following aspects:(1) Using cluster-heads rotation mechanism. The cluster-heads selecting is not periodically rotation,but into consideration on the remaining energy of the cluster-heads and select the codes have a certain amount of surplus energy as cluster- heads. After the construction of cluster,setting a energy threshold in the cluster in order to realize the cluster-heads rotation mechanism.Comparing the left power of the cluster-head with the energy threshold,if the power is less, the new choosing about the cluster-head will beging.Only the left power of the other nodes is not less than the energy threshold,they could be the cluster-heads.Of course,if the left power of the cluster-head is more than energy threshold,the change is not required.(2) We adopt TDMA to communicate in the cluster.The senor nodes are primarily in charge of the real-time monitoring of the environmental information and senting the data to cluster-heads.Every code entirely sents data to the cluster-heads.However,the data of the nodes only transport one by one.So one slot table is necessary which assigns different time for the transmission of every node in the cluster.If the data of one node is transporting, the other nodes can shut down their wireless transceivers so as to save the power.(3) During the clusters, the transmission will adopt the multi-hop mode.Considering the monitoring area of farmland are vaster,the energy consumption of the long distance from clusters to base station is more.That can lead to use the power up.Therefore,the transmission routing among the cluster should be built firstly before transporting data to base station.The data will be transported down the routing until arrive the base station on level.更多还原