Celaya-Echarri Mikel, Azpilicueta Leyre, Lopez-Iturri Peio, Picallo Imanol, Aguirre Erik, Astrain Jose Javier, Villadangos Jesús, Falcone Francisco
School of Engineering and Sciences, Tecnologico de Monterrey, 64849 Monterrey, NL, Mexico.
Electric, Electronic and Communication Engineering Department, Public University of Navarre, 31006 Pamplona, Navarra, Spain.
Sensors (Basel). 2020 Nov 24;20(23):6710. doi: 10.3390/s20236710.
The significant growth of wireless communications systems in the last years has led to the adoption of a wide range of applications not only for the general public but, also, including utilities and administrative authorities. In this context, the notable expansion of new services for smart cities requires, in some specific cases, the construction of underground tunnels in order to enable the maintenance and operation works of utilities, as well as to reduce the visual impact within the city center. One of the main challenges is that, inherently, underground service tunnels lack coverage from exterior wireless communication systems, which can be potentially dangerous for maintenance personnel working within the tunnels. Accordingly, wireless coverage should be deployed within the underground installation in order to guarantee real-time connectivity for safety maintenance, remote surveillance or monitoring operations. In this work, wireless channel characterization for complex urban tunnel environments was analyzed based on the assessment of LoRaWAN and ZigBee technologies operating at 868 MHz. For that purpose, a real urban utility tunnel was modeled and simulated by means of an in-house three-dimensional ray-launching (3D-RL) code. The utility tunnel scenario is a complex and singular environment in terms of radio wave propagation due to the limited dimensions and metallic elements within it, such as service trays, user pathways or handrails, which were considered in the simulations. The simulated 3D-RL algorithm was calibrated and verified with experimental measurements, after which, the simulation and measurement results showed good agreement. Besides, a complete wireless sensor network (WSN) deployment within the tunnels was presented, providing remote cloud data access applications and services, allowing infrastructure security and safety work conditions. The obtained results provided an adequate radio planning approach for the deployment of wireless systems in complex urban utility scenarios, with optimal coverage and enhanced quality of service.
近年来，无线通信系统的显著增长促使了广泛应用的采用，这些应用不仅面向普通大众，还包括公用事业和行政当局。在此背景下，智能城市新服务的显著扩展在某些特定情况下需要建造地下隧道，以便进行公用事业的维护和运营工作，并减少市中心的视觉影响。主要挑战之一是，地下服务隧道本质上缺乏外部无线通信系统的覆盖，这对在隧道内工作的维护人员可能存在潜在危险。因此，应在地下设施内部署无线覆盖，以确保安全维护、远程监控或监测操作的实时连接。在这项工作中，基于对工作在868MHz的LoRaWAN和ZigBee技术的评估，分析了复杂城市隧道环境的无线信道特性。为此，通过内部三维射线发射（3D-RL）代码对实际城市公用事业隧道进行了建模和模拟。由于公用事业隧道场景的尺寸有限且内部存在金属元素，如服务托盘、用户通道或扶手，在模拟中予以考虑，所以就无线电波传播而言，它是一个复杂且独特的环境。模拟的3D-RL算法通过实验测量进行了校准和验证，之后，模拟和测量结果显示出良好的一致性。此外，还展示了在隧道内完整的无线传感器网络（WSN）部署，提供远程云数据访问应用和服务，确保基础设施的安全工作条件。所得结果为在复杂城市公用事业场景中部署无线系统提供了一种合适的无线电规划方法，具有最佳覆盖和更高的服务质量。
