# Review of Physical Layer Security in 5G Wireless Networks
## 3 Literature Review
To match the presentation of DCE with other privacy strategies, quantitative studies are needed. To offer reliable and secure communication, future work should concentrate on combining DCE with MIMO-based secrecy approaches. Figure 2: The fundamental physical layer security channel model, which consists of three nodes: [PERSON] (legitimate transmitter), [PERSON] (legitimate receiver), and [PERSON] (eavesdropper). [PERSON] and [PERSON] et al. [12] declared that due to the widespread use of wireless devices in modern life, an extraordinary quantity of private and complex info is exchanged across wireless stations. As a consequence of the wireless medium's inherent openness, security challenges related to wireless communications have grown urgent. From a practical standpoint, the privacy outage likelihood has two boundaries: (1) it cannot characterize the quantity of data that is disclosed to an observer when an outage happens, and (2) it cannot provide any info regarding the listener's capacity to decipher personal messages. In this study, they offer three novel secrecy metrics for secure broadcasts over quasistatic disappearing channels, which are encouraged by the constraints of the privacy outage likelihood. The first measure provides a connection between the idea of a privacy outage and the ability of an eavesdropper to decode messages. For the practical implementation of secure wireless networks, the second metric offers an error probability-based secrecy meter. The third statistic describes how much or how quickly private information is disclosed to the listener. They demonstrate how the proposed secrecy metrics, when taken as a whole, provide a more thorough knowledge of physical layer safety over disappearing channels and allow one to properly design protected message systems with various secrecy measurement philosophies. [PERSON] et al. [13] described research that proposes a physical-layer refuge pattern for an inspired relay-based cognitive radio network (CRN), where the medium access technology is an orthogonal frequency-division multiplexing (OFDM). The issue of spectrum scarcity, which is brought on by the widespread usage of wireless range for multiple determinations, is addressed by cognitive radio. In cognitive radio linkages, a secondary consumer, or cognitive radio (CR) consumer, can unscrupulously access the spectrum used by the primary user (PU), as long as the PU is sedentary as long as the level of interference from the CR user communications with PU communications is below a predetermined threshold. The suggested technique can greatly increase the confidentiality rate while sustaining the interference limits put in place to protect the PU's transport network from damaging interference, as demonstrated by simulation results. We also demonstrated that, despite being computationally simpler, the suggested strategy closely approximates the exhaustive search technique, which serves as its upper bound. [PERSON] et al. [14] proposed a two-stage safe hybrid beamforming technique with artificial noise (AN) assistance, suggested for MIMO mm-wave relay systems from the standpoint of physical layer security. Wireless service providers are under increased pressure to solve the world's bandwidth constraint as a result of the explosive rise of mobile data traffic and mobile terminals. One of the most important technologies for upcoming mobile communications is millimeter wave (mm-wave), which can offer spectrum resources up to GHz bandwidth. Traditional microwave systems incorporate the beamforming methods in the baseband using digital signal processing, which gives the beamforming matrices better control. RF chains are normally used significantly less frequently than antennas in mm-wave communications. They amplify and forward (AF) relaying systems, which is the subject of the proposed method. In this system, K data streams are transmitted by the source during phase I, and during phase II, the relay amplifies the signals it receives and transmits them to all K destinations.