When wireless sensor networks (WSN) are deployed in the vegetablegreenhouse with dynamic connectivity and interference environment, it is necessary to increase the node transmit power to ensure the communication quali...When wireless sensor networks (WSN) are deployed in the vegetablegreenhouse with dynamic connectivity and interference environment, it is necessary to increase the node transmit power to ensure the communication quality,which leads to serious network interference. To offset the negative impact, thetransmit power of other nodes must also be increased. The result is that the network becomes worse and worse, and node energy is wasted a lot. Taking intoaccount the irregular connection range in the cucumber greenhouse WSN, wemeasured the transmission characteristics of wireless signals under the 2.4 Ghzoperating frequency. For improving network layout in the greenhouse, a semiempirical prediction model of signal loss is then studied based on the measureddata. Compared with other models, the average relative error of this semi-empiricalsignal loss model is only 2.3%. Finally, by combining the improved networktopology algorithm and tabu search, this paper studies a greenhouse WSN layoutthat can reduce path loss, save energy, and ensure communication quality. Giventhe limitation of node-degree constraint in traditional network layout algorithms,the improved algorithm applies the forwarding constraint to balance network energyconsumption and constructs asymmetric network communication links. Experimentalresults show that this research can realize the energy consumption optimization ofWSN layout in the greenhouse.展开更多
文摘为适应下一代微功率无线抄表技术发展的需要,针对470~510 MHz特定频段在室内和室外环境中进行信道特性测量并提取信道特性参数,建立路径损耗模型。测量过程中,发射端使用SMW200A矢量信号发生器发送信号,利用频域测量系统的扫频测量法,在室内办公室环境和室外郊区环境中抓取测量数据,同时考虑信号在室内传输过程中墙壁、门窗开闭以及室外行人、车辆、树木等障碍物的影响,分析其大尺度衰落特性。根据测量数据,利用最小二乘法和中心极限定理估算路径损耗模型中的路径损耗因子 n 和标准偏差σ,得出在室内视距情况下470~510 MHz频段的路径损耗模型和室外郊区空旷地带的路径损耗模型。测量和仿真结果表明,该路径损耗模型能较好地预测接收信号强度,为后续测量和抄表业务部署提供依据。
基金funded by the National Natural Science Foundation of China(grant number 61871041)Technical System of the National Bulk Vegetable Industry(grant number CARS-23-C06).
文摘When wireless sensor networks (WSN) are deployed in the vegetablegreenhouse with dynamic connectivity and interference environment, it is necessary to increase the node transmit power to ensure the communication quality,which leads to serious network interference. To offset the negative impact, thetransmit power of other nodes must also be increased. The result is that the network becomes worse and worse, and node energy is wasted a lot. Taking intoaccount the irregular connection range in the cucumber greenhouse WSN, wemeasured the transmission characteristics of wireless signals under the 2.4 Ghzoperating frequency. For improving network layout in the greenhouse, a semiempirical prediction model of signal loss is then studied based on the measureddata. Compared with other models, the average relative error of this semi-empiricalsignal loss model is only 2.3%. Finally, by combining the improved networktopology algorithm and tabu search, this paper studies a greenhouse WSN layoutthat can reduce path loss, save energy, and ensure communication quality. Giventhe limitation of node-degree constraint in traditional network layout algorithms,the improved algorithm applies the forwarding constraint to balance network energyconsumption and constructs asymmetric network communication links. Experimentalresults show that this research can realize the energy consumption optimization ofWSN layout in the greenhouse.
