## 1 Introduction
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Existing Papers** & **Research Issues** & **Important Content** \\ \hline
[12] & \
\begin{tabular}{c} Examine the security threats and \\ corresponding defense methods in \\ PHY security. \\ \end{tabular} &
\begin{tabular}{c} Summary of the security requirements and threats in wireless \\ networks considering the network protocols at various levels of \\ data layers. Additionally, a comprehensive review of \\ state-of-the-art PHY security and existing security protocols for \\ 13 various wireless networks. \\ \end{tabular} \\ \hline
[25] & \
\begin{tabular}{c} A comprehensive survey on the basic \\ theories and key technologies of \\ PHY security. \\ \end{tabular} &
\begin{tabular}{c} Discussion of the key technologies, limitations, and solutions of \\ PHY security from the perspective of security coding, \\ physical-layer authentication, secret key generation, and \\ multi-antenna techniques. \\ \end{tabular} \\ \hline
[26] & \
\begin{tabular}{c} Security threats and the corresponding \\ countermeasure techniques. \\ \end{tabular} &
\begin{tabular}{c} Technologies, security attacks, and defense mechanisms in PHY \\ security using game-theoretic approaches. \\ \end{tabular} \\ \hline
[27] & \
\begin{tabular}{c} Overview of the key technologies of \\ PHY security. \\ \end{tabular} &
\begin{tabular}{c} Recent technologies, optimization techniques, and limitations of \\ PHY security from the perspective of information-theoretic \\ security and wiretap channels. \\ \end{tabular} \\ \hline
[28] & \
\begin{tabular}{c} A comprehensive investigation of \\ multi-antenna techniques. \\ \end{tabular} &
\begin{tabular}{c} Survey of multi-antenna techniques in multi-user networks for \\ improving the security performance of PHY security, but not \\ considering CSI accuracy. \\ \end{tabular} \\ \hline
[29] & \
\begin{tabular}{c} A brief survey on multi-antenna \\ techniques. \\ \end{tabular} &
\begin{tabular}{c} Investigation on multi-antenna techniques in PHY security for \\ improving secrecy performance considering the accuracy \\ of CSI. \\ \end{tabular} \\ \hline
[30] & \
\begin{tabular}{c} A comprehensive overview of the \\ optimization and design strategies of \\ PHY security. \\ \end{tabular} &
\begin{tabular}{c} Survey on security designs and optimization techniques from \\ the viewpoints of information theory and security metrics in \\ wireless PHY security. \\ \end{tabular} \\ \hline
[31] & \
\begin{tabular}{c} Comprehensive overview of all existing \\ PHY security techniques. \\ \end{tabular} &
\begin{tabular}{c} Classification of the existing PHY security techniques and brief \\ discussion of the big picture they can be easily understood and \\ applied in different communication systems. \\ \end{tabular} \\ \hline
[32] & \
\begin{tabular}{c} Challenges of PHY security in real-world \\ systems. \\ \end{tabular} &
\begin{tabular}{c} Identification of the existing assumptions and opportunities for \\ applying PHY security in practical applications. \\ \end{tabular} \\ \hline
[34] & \
\begin{tabular}{c} A comprehensive investigation of AI \\ and edge \\ computing (EC) for PLS. \\ \end{tabular} &
\begin{tabular}{c} Identification of the existing challenges in the design and \\ optimization of PLS and design of an enhancement scheme for \\ PLS application. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of related studies. \begin{table}
\begin{tabular}{c c} \hline \hline
**Acronyms** & **Full-Form Definition** \\ \hline
5G & Fifth-generation mobile networks \\ AI & Artificial intelligence \\ AF & Amplify-and-forward \\ ANN & Artificial neural networks \\ AWGN & Additive white Gaussian noise \\ B5G & Beyond fifth-generation networks \\ BER & Bit error rate \\ BLER & Block error rate \\ CNN & Convolutional neural network \\ CSI & Channel state information \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Abbreviations and their full form definitions.