基于发射功率自适应的稻田无线传感器网络节点设计

发布时间：2018-09-01 08:23

【摘要】：针对水稻生长过程环境因素变化较大以及传感器节点的能量大部分被无线射频阶段所消耗,设计了发射功率自适应的无线传感器节点,建立了长时间、稳定、高可靠性的稻田无线传感器网络。试验测试了水稻的株高、叶面积与生长天数的关系以及对无线信道的影响,结果表明水稻株高和叶面积的增加会降低无线信号强度和通信成功率;通过增大发射功率可以提高通信质量克服由于水稻生长因数对无线信道的影响。在软件设计方面,传感器节点采用睡眠、苏醒工作机制来降低功耗。同时为了延长工作时间、提高通信质量,提出了根据水稻生长周期、通信距离、接收信号强度、平均丢包率等因素自动调整节点发射功率的能量自适应功耗调整机制。田间试验结果表明,水稻田节点发射功率越大,有效通信距离越远,且水稻的密度和高度等对通信有重要的影响;节点发射功率在5 dBm以下时,发射功率的改变对节点工作电流影响较小,节点工作电流均小于40 mA;采用该机制对发射功率进行调整,增大节点发射功率可使通信成功率有大幅的提升;降低节点发射功率仍然保持良好的通信效果。水稻分蘖和抽穗2个生长时期的田间试验结果表明,采用发射功率自适应策略,提高了通信质量,平均丢包率在5%以下,通信成功率大于97%,达到了预期设计目的。
[Abstract]:In view of the great changes of environmental factors during rice growth and the fact that most of the energy of sensor nodes is consumed by radio frequency, a wireless sensor node with adaptive transmitting power is designed. A long-term, stable and reliable wireless sensor network for rice field is established. The plant height, leaf area and growing days of rice are tested. The results show that the increase of rice plant height and leaf area will reduce the wireless signal strength and communication success rate, and the increase of transmitting power can improve the communication quality to overcome the influence of rice growth factor on wireless channel. In order to prolong the working time and improve the communication quality, an energy adaptive power adjustment mechanism is proposed, which can adjust the transmitting power automatically according to the rice growth period, communication distance, received signal strength and average packet loss rate. The farther the distance is, and the density and height of rice have an important impact on communication; when the transmitting power is below 5 dBm, the change of transmitting power has little effect on the working current of the node, and the working current of the node is less than 40 mA; the transmission power can be adjusted by this mechanism, and the success rate of communication can be greatly improved by increasing the transmitting power of the node. The field experiment results of two growing stages of rice tillering and heading showed that the average packet loss rate was less than 5% and the communication success rate was more than 97%. The expected design goal was achieved.
【作者单位】：华南农业大学工程学院;华南农业大学南方农业机械与装备关键技术教育部重点实验室;
【基金】：国家高技术研究发展计划(863计划)资助项目(2011AA100704) NSFC-广东联合基金资助项目(U0931001)
【分类号】：TP212.9;TN929.5;S511

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