The application of the Internet of Things in agricultural development usually occurs via a monitoring network that consists of a large number of sensor nodes, thus gradually transforming agriculture from a human-oriented and single-machine-centric production model to an information- and software-centric production model. Due to the large area coverage of agriculture and the variety of production objects, if all farmland perception information is gathered into the cloud server, the server will exert greater pressure on the network, which reduces the speed of response to event processing. This problem may be perfectly solved by the recent emergence of Edge computing, which can share the load of the cloud server and reduce the delay. Edge computing has prospects in agricultural applications, such as pest identification, safety traceability of agricultural products, unmanned agricultural machinery, agricultural technology promotion, and intelligent management. The application of the Agricultural Internet of Things integrates artificial intelligence, the Internet of Things, and blockchain and Virtual/Augmented Reality technologies. This paper primarily reviews the application of Edge computing in the Agricultural Internet of Things and investigates the combination of Edge computing and Artificial Intelligence, blockchain and Virtual/Augmented reality technology. The challenges of Edge computing task allocation, data processing, privacy protection and security, and service stability in agriculture are reviewed. The future development direction of Edge computing in the Agricultural Internet of Things is predicted.

To meet the requirements of long range, a small amount of data transmission, low power, and low cost of the Internet of Things (IoT) in actual applications, a Low-Power Wide-Area Network (LPWAN) information monitoring approach based on NB-IoT and LoRa is proposed in this paper. This approach adopts a communication mode that contains a main node and multiple subnodes to adapt to the needs of large-scale information monitoring. Among them, the design of the main node utilizes NB-IoT communication technology, LoRa communication technology, and LRU algorithm. The design of subnode utilizes LoRa communication technology, sensor technology, and optical-electric conversion technology. Finally, we design and implement a cloud service and computing system, using the Tencent Cloud server. The advantage of this approach is that the combination of NB-IoT and LoRa not only improves transmission distance but also reduces the operating costs of the WAN information monitoring system. In addition, using optical-electric conversion technology, the system can be self-powered. Combined with the principle of electric circuits, the power consumption of the system can also be reduced. Finally, by conducting a system test, LoRa communication distance experiment, NB-IoT communication, and other experiments, the communication distance in a complex environment is up to 1.6 km, the minimum working current is 2 mA, and the system communication packet loss rate is approximately 3%. The system runs stably and the collected data are accurate. The results show that the proposed approach can meet the requirements of data collection, transmission, storage, and calculation in a wide area.

Since transmission towers are generally located in areas with complex geological environments, such as mountains and rivers, relying only on conduct regular personnel inspections wastes considerable human and material resources. At present, the existing monitoring system has also the problems of data transmission, parameter accuracy and transmission distance. Based on this premise, a novel transmission tower tilt monistoring system was proposed in this paper. This research adopted the latest Low-Power Wide-Area Network (LPWAN) technology. Among tehm, LoRa (Long Range) is a modulation technology that provides a longer communication distance. NB-IoT (Narrow Band-Internet of Things ) technology is an emerging technology in the IoT field that supports the cellular data connection of low-power devices in a wide area network. The proposed system through the data transmission of a LoRa multinode network, the tilt parameters of tower were uploaded to an online real-time monitoring system through NB-IoT. Each subnode included MPU6050 tilt sensors and a wireless communication LoRa module. The main node contained an NB-IoT module. It can upload the tilt information to the cloud platform. After uploading the data, administrators can arrange timely targeted maintenance for transmission towers with faults according to the analysis results. The proposed approach covers a wide range, has high service quality, and supports many connections.

The adaptive data rate (ADR) algorithm is used in LoRaWAN, allocating an appropriate transmission rate for terminal equipment to improve channel utilization and reduce power consumption. However, the standard ADR algorithm is only suitable for static terminal equipment. In addition, due to the complexity of the external environment, the selected data rate will not match the new environment and communication packets will be lost. Therefore, this article proposed a novel and more effective ADR algorithm called new-dynamic ADR (ND-ADR). The algorithm mainly solves two problems, i.e., the standard ADR algorithm cannot be applied to mobile terminal devices and the poor communication quality and high packet loss rate in harsh environments. In this study, we also developed a frame for LoRaWAN (FLoRaWAN), a simulation framework for the star network topology LoRaWAN in OPNET. Furthermore, we built an OKUMURA–HATA model and additionally introduced a noise factor $\beta$ to simulate the loss of wireless communication in harsh environments. Finally, extensive simulation results showed that the number of data packets required by different end nodes for rate allocation was different. Compared with the standard ADR algorithm, even for mobile nodes in harsh environments, the ND-ADR algorithm reduced network energy consumption by about 13%, reduced network delay by about 18%, and increased effective throughput by about 15%. Therefore, the improved ND-ADR algorithm is more suitable for wireless communication of removable nodes in harsh environments. Its advantages are better awareness of link environment, faster data rate regulation, improved channel utilization, and further reduction of network energy consumption.

Line joint temperature monitoring is used in high-voltage transmission lines to improve the reliability and safety of power lines. However, traditional monitoring methods (e.g., manual inspection, UAV inspection, short-range wireless technology, etc.) cannot realize real-time monitoring of line joint temperature in remote areas. In this paper, we proposed a novel real-time monitoring system, which adopted a communication method combining ZigBee and LPWAN technology (LoRa and NB-IoT) for long-distance transmission. In this system, each power tower was regarded as a communication node that contained a main node and multiple subnodes. First, each node collected temperature data of the transmission line junctions by ZigBee and microprocessor processed and analyzed the data. Second, the LoRa multihop communication technology was used for transmission of the data between adjacent nodes to achieve wider coverage and a longer transmission distance. Finally, the end of the network was a main node, i.e., an LoRa-NB-IoT gateway. The temperature data of all nodes were transmitted to the “USR Cloud” by the NB-IoT technology. By conducting a system test, the system can meet the requirements of long-distance communication outside and reduce power consumption. After calculation, the system communication packet loss rate is approximately 3.3%, and the average power consumption of the system is about 21.19 mA. The PC can monitor the transmission line junction temperature in real time, transmission is stable, and the alarm function can be also realized. Therefore, the system is more suitable for temperature monitoring of line junctions in remote areas, achieving long-distance data acquisition and transmission through low power consumption and high transmission rate.