# Machine Learning for Physical Layer in 5G and beyond Wireless Networks: A Survey
## 4 Security and Privacy in 5G
In [309], the authors also followed the same approach in which a low pass filter (LPF) achieved high authentication, improved channel reciprocity, suppressed channel fluctuations, and reduced fundamental disagreement in the OFDM subcarrier's channel. The authors conducted another work to enhance channel reciprocity and CSI [310]. In this paper, the authors first demonstrated the interference and vulnerable noises present in the systems due to channel variations, synchronization offset, fingerprint issues, and nonreciprocity in frequency division duplex systems. Then, they adopted the loopback approach by exploiting frequency bands in different time slots known as LB-TDD. Through theo \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Standard Body** & **Work Groups** & **Focused Area** & **Breakthrough** \\ \hline \multirow{7}{*}{3 GPP} & & Security architecture, security aspects, & TS 33.102,TR 33.899, \\  & & fraud information gathering system, & TS 22.031,TS 23.031, \\  & & cryptographic algorithm requirements, & TS 33.105,TR 33.901, \\  & & lawful interception requirements, & TS 33.106, TS 33.126, \\  & & security assurance specification, & TS 33.511,TS 33.326, \\  & & generic authentication architecture, & TS 33.220,TR 33.918, \\  & & network domain security. & TS 33.210,TR 33.810. \\  & & Security requirements and risks, & Report 1.4,Report 1.5, \\  & & security architecture and enablers, & Report 2.1,Report 2.3, \\
5 GPP & Security WG & access control, slicing and MEC security, & Report 3.1,Report 3.2, \\  & & privacy and trust in 5G, & Report 5.2,Report 5.3, \\  & & security architecture and solutions, & Report 6.2,Report 6.3, \\  & & policy management and orchestration. & Report 6.4. \\  & & i2 nsf & Network security function, & RFC8192,RFCS329, \\  & & ipsecme & IPSec, & RFC9061,RFCS983, \\  & & sacm & automation and continuous monitoring, & RFC5898,RFCS784, \\  & & secdispatch, & security dispatch, & RFC7632,RFCS248,RFCS412, \\  & & secevent & security events, & RFC8936,RFCS935,RFCS417, \\  & & tls & transport layer security, & RFC8996,RFCS744,RFCS773, \\  & & opsec & operational security. & RFC9099,RFCS704,RFC7707. \\  & & Security consideration for 5G, & White paper V-1.0, \\  & & NGMN alliances & sustainable trust, & White paper V-1.0, \\  & & 5G end-to-end architecture framework, & White paper V-4.31, \\  & NGMN 5G security group & 5G security recommendations, & White paper V-1.0, \\  & & 5G security network slicing. & White paper V-1.0. \\  & & Authentication mechanisms, & ETSI TR 103 692, \\  & & quantum cryptography, & ETSI TR 103 823, \\  & & Internet of Things, & ETSI TS 103 701, \\ ETSI & Cyber security & security threats analysis, & ETSI TR 103 743, \\  & & access control, & ETSI TS 103 532, \\  & & infrastructure cybersecurity. & ETSI TR 103 741. \\  & & Security assurance, & Recommendation X.1404, \\  & & security threats, & Recommendation X.1408. \\  & & security framework and requirements, & Recommendation X.1145, \\ ITU & SG-17 & secure protection guidelines, & Recommendation X.1146, \\  & & risk identification, & Recommendation X.1451, \\  & & guidelines for security services. & Recommendation X.1452. \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Standard bodies working in the security and privacy domain. retical analyses, this scheme outperformed other approaches and brought tremendous results in terms of eradicating both eavesdropping (passive attack) and man in the middle (active attack) attacks compared to the classical TDD scheme while considering the key generation rate and disagreement rate factors. Furthermore, the authors designed a secret key generation protocol and proved it to be viable for mitigating interference in TDD systems through experimental and simulation results. In [311], the authors generated the secret key in an in-band full-duplex communication system (IBFD); both half-duplex and full-duplex modes were simulated.