无线智能电表信道路径损耗建模

Modeling of channel pathloss in wireless smart meter

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。

In order to meet the needs of the development of next-generation micro-power wireless meter reading technology, this paper conducts channel characteristics measurement and extracts channel characteristic parameters in indoor and outdoor environments for specific frequency bands of 470~510 MHz, and establishes a pathloss model. During the measurement process, the transmitting end uses the SMW200A vector signal generator to transmit signals, and uses the frequency-frequency measurement system’s sweep frequency measurement method to capture measurement data in the indoor office environment and the outdoor suburban environment, while considering the signal during the indoor transmission process, The large-scale fading characteristics of the doors and windows are opened and closed and the obstacles such as pedestrians, vehicles and trees are analyzed. According to the measured data, the pathloss factor N and standard deviation sigma in the pathloss model are estimated by using the least square method and the central limit theorem. The pathloss model of the 470~510MHz band in the indoor sight distance and the pathloss model in the open outskirts of the outdoors are obtained. Measurement and simulation results show that the pathloss model can better predict the received signal strength, and provide a basis for subsequent measurement and meter reading service deployment.