# Machine Learning for Physical Layer in 5G and beyond Wireless Networks: A Survey
## 4 Security and Privacy in 5G
\begin{table}
\begin{tabular}{l l c c c c c} \hline \hline
**Security Threat/Attacks** & **Targeted Network Elements** & **SDN** & **NFV** & **Cloud** & **Links** & **Privacy** & **References** \\ \hline Boundary attacks & Subscriber location & \(\bigtimes\) & \(\bigtimes\) & \(\bigtimes\) & \(\bigtimes\) & \(\bigvee\) & [315] \\ Configuration attacks & Virtual switches and routers & \(\bigvee\) & \(\bigvee\) & \(\bigtimes\) & \(\bigtimes\) & \(\bigtimes\) & [316] \\ DoS attack & Centralized elements & \(\bigvee\) & \(\bigvee\) & \(\bigtimes\) & \(\bigtimes\) & [317] \\ Hijacking attacks & SDN controller and hypervisor & \(\bigvee\) & \(\bigvee\) & \(\bigtimes\) & \(\bigtimes\) & [318] \\ IMSI catching attacks & Subscriber Identity & \(\bigtimes\) & \(\bigtimes\) & \(\bigtimes\) & \(\bigvee\) & [319] \\ MITM attack & SDN communication & \(\bigvee\) & \(\bigtimes\) & \(\bigvee\) & \(\bigvee\) & [320] \\ Penetration attacks & Virtual resources and clouds & \(\bigvee\) & \(\bigtimes\) & \(\bigvee\) & \(\bigtimes\) & [321] \\ IP spoofing & Control channels & \(\bigtimes\) & \(\bigtimes\) & \(\bigvee\) & \(\bigtimes\) & [322] \\ Resource attacks & Shared cloud resources & \(\bigtimes\) & \(\bigvee\) & \(\bigvee\) & \(\bigtimes\) & [323] \\ Saturation attacks & SDN controller and switches & \(\bigvee\) & \(\bigtimes\) & \(\bigtimes\) & \(\bigtimes\) & [324] \\ Scanning attacks & Open air interfaces & \(\bigtimes\) & \(\bigtimes\) & \(\bigvee\) & [325] \\ Encryption keys attack & Unencrypted channels & \(\bigtimes\) & \(\bigtimes\) & \(\bigvee\) & \(\bigtimes\) & [326] \\ Semantic-info attacks & Subscriber location & \(\bigtimes\) & \(\bigtimes\) & \(\bigvee\) & \(\bigvee\) & [327] \\ Signaling storms attack & 5G core network elements & \(\bigtimes\) & \(\bigvee\) & \(\bigvee\) & \(\bigtimes\) & [328] \\ TCP level attacks & SDN communication & \(\bigvee\) & \(\bigtimes\) & \(\bigvee\) & \(\bigtimes\) & [329] \\ Timing attacks & Subscriber location & \(\bigtimes\) & \(\bigvee\) & \(\bigtimes\) & \(\bigvee\) & [330] \\ User identity attack & User information databases & \(\bigtimes\) & \(\bigtimes\) & \(\bigvee\) & \(\bigtimes\) & [331] \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Summary of studies on 5G security and privacy threats. Figure 8: Fifth-generation network security architecture system. of physical layer security but could not illustrate the case of multi-casting and broadcasting services. For this purpose, the concept of physical layer service integration was proposed [334]. Physical layer service integration (PHY-SI) provides two types of services: confidential services and public services. As the name indicates, confidential services are paid, whereas public services are free to support broadcast applications. Depending on their preferences, multiple users subscribe to these services and use them according to their demands. The public information is distributed to all users, and private data are kept confidential so that only limited users can access them. This shows that PHY-SI has a more secure and encrypted transmission than the physical layer. Both have their characteristics and points of divergence [335], as listed below. * Shared information: For each message in the physical layer, security has a confidential shield--unauthorized users cannot share and access information. However, in the case of PHY-SI, the medium is served to transfer both public and private information at once. Public and confidential information waveforms are superimposed at the transmitting antenna and follow the channel path. * Secrecy rate: In physical-layer security, only a single secrecy rate is used to perform the protection of signals, and the design of the system is maintained to maximize this rate. However, in PHY-SI, a Pareto transmit scheme is used to optimize the capacity of the secrecy rate, and each service has a different transmitting rate. These transmitting rates then combine to form a secrecy platform. * Security issues: PHY-SI suffers more interference as compared to physical layer security.