# Robot Delay-Tolerant Sensor Network for Overhead Transmission Line Monitoring
## 5 Discussion  
The idea of RDTSN is derived from the rapid development and application of WSN technology, DTSN technology and robot technology. The most significant characteristic of RDTSN is wireless transmission of the inspection data by the inspection robots and the static nodes along a ground wire. Its communication mode is different from the real-time network with low delay and high cost of operation and maintenance. It is also different from Vehicle Delay-Tolerant Networks whose wireless signal could be frequently blocked by trees and buildings, etc. WSN and robot technologies have been rapidly developing in recent years, especially in terms of the light weight and cost-effectiveness of hardware. Thus, it becomes possible to build a WSN with a robot as the core node and propose a new method for monitoring high-voltage lines. RDTSN, combining the characteristics of WSN, Robot and DTSN, is very distinctive network. Firstly, the network structure is changeable and flexible for mobile robots as the intermediate transmission point of information; secondly, the network has the properties of delay-tolerance and intermittent connectivity; thirdly, as fewer nodes are deployed, the deployment costs are decreased, and the fault-tolerant performance is improved. These characteristics of RDTSN provide a strong technological support for the security of inspection data. The main contribution of the proposed method is to enhance the intelligent level of power grid monitoring system and the data transmission quality of patrolling line. At present, the robot mainly uses the point-to-point communication mode when it is inspecting the transmission line. That is, a robot can only communicate with one MMS. Thus, such a communication mode seriously restricts the large-scale application of robotic line inspection. In this paper, a highly practical robot delay-tolerant sensor network (RDTSN) is proposed, which greatly reduces the workload of operators and improves the intelligence level of the transmission line inspection. Further, this research makes a new attempt in theory: The motion model of the inspection robot is analyzed and summed up, and the delivery rate and energy consumption factor are introduced for the mathematical modeling of RDTSN. Under the premise of guaranteeing the message delivery rate, the energy consumption of the node is reduced and the network life is extended. Finally, we design the routing algorithm (DTMA) based on the mathematical model, which balances the relationship between the delivery rate and the energy consumption, compares and chooses the optimized destination of the message, which greatly improves the reliability and practicability of the network. In addition, this can be seen from the simulation result. The proposed method also needs improvement in several aspects in practical applications. Firstly, the RDTSN's data has a high delay--as the result is shown in Section 4 there are over 60 min delay in general--and it is difficult to alarm the line burst fault in timely manner. This means the monitoring network can only do routine inspection and a lagged processing of the fault point. In addition, RDTSN is not compared with other methodologies and telecommunications technologies such as LPWAN (Low-Power Wide-Area Network). A more reasonable method combines LPWAN, and other technologies are going to be adopted to improve delivery time and energy consumption. Secondly, the adaptive adjustment of network message delivery and energy consumption cannot be realized  
Figure 34: Result of field experiments and simulations. currently. The energy factor in the method needs to be preset, as we did in Section 4.2. An intelligent algorithm, such as the deep learning method, can be possibly introduced to realize the adaptive adjustment of energy factor. Thirdly, the RDTSN-optimized routing algorithm (DTMA) reduces network energy consumption under the premise of ensuring a better message delivery rate.