# Image Transmission over Cognitive Radio Networks for Smart Grid Applications
## 1 Introduction
For example, wind turbines (WTs) are considered as high-cost devices that have advance maintenance services [30]. The WT conditional monitoring and diagnostics are actually a complex challenge. In order to increase the lifetime of WTs and reduce the maintenance cost, it is essential to have accurate prediction of system faults and failures using advanced Non Destructive Tests (NDTs) methods during in-service operation [31]. These systems usually benefits smart sensors with artificial intelligence and machine learning techniques to perform advance inspections [5; 32; 33; 34; 35; 36]. In this paper, our main goal is to implement an appropriate wireless telecommunication infrastructure to send images of thermal cameras mounted on wind turbine towers (WTTs). For this purpose, an efficient design of the Media Access Control (MAC) layer based on cognitive radio (CR) technology with consideration of delay constraints which were defined in smart grid standards is aimed. This communication structure provides inspection tools for fault detection and NDTs purposes in wind farms. This platform can also be used to prevent outage and its consequences. However, it \begin{table}
\begin{tabular}{c c c} \hline \hline
**Information Types** & **Internal to Substation** & **External to Substation** \\ \hline Protection information & 4 ms & 8–12 ms \\ \hline Monitoring and control & 16 ms & 1 s \\ \hline Operations and maintenance & 1 s & 10 s \\ \hline Text strings & 2 s & 10 s \\ \hline Processed data files & 10 s & 30 s \\ \hline Program files & 60 s & 600 s \\ \hline Image files & 10 s & 60 s \\ \hline and Video data streams & 1 s & 1 s \\ \hline \hline \end{tabular}
\end{table} 
Table 1: IEEE 1646 standard on communication timing requirements for electric substation automation [29]. \begin{table}
\begin{tabular}{c l c} \hline \hline
**Message Type** & **Example Application** & **Time Constraint** \\ \hline Type 1 & Fast messages such as circuit breaker & 1 A: 3 ms or 10 ms, 1 B: 20 ms \\  & commands and states & or 100 ms \\ \hline Type 2 & Medium speed messages & 100 ms \\ \hline Type 3 & Low speed messages such as Alarms, & 500 ms \\  & non-electrical measurements, configurations & \\ \hline Type 4 & Raw data messages such as Digital & 3 ms or 10 ms \\  & representation of electrical measurement (SV) & \\ \hline Type 5 & Large file transfer for example image, video, & 1000 ms \\  & and files of data for recording settings & \\ \hline Type 6 & Time synchronization messages such as IED & None \\  & internal clock synchronization & \\ \hline Type 7 & Command messages with access control & Equivalent to Type 1 or Type 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: IEC 61850 communication networks and systems in substations: communication requirements for functions and device models in Smart Grids (SGs) [28]. is subject to the accuracy of the performance of the communication network and its efficiency. The remainder of the paper is written as follows: In Section 2, related works are discussed. In Section 3, the proposed MAC layer model is elaborated in full details. Then in Section 4, obtained results of our simulations are presented and finally, the conclusion and discussion are stated in Section 5.