# Review of Physical Layer Security in 5G Wireless Networks
## 1 Introduction  
Physical layer security (PLS), which acts at the physical layer of the communication system, is a new method for securing wireless communication. PLS is essential to the security, integrity, and availability of user data in 5G wireless networks. PLS offers security without relying on cryptographic methods, which can be computationally demanding and subject to assaults, which is one of its key benefits. To establish a secure communication link between the sender and receiver, PLS instead takes advantage of the special characteristics of wireless communication channels, such as fading, interference, and noise. Beamforming is the name of one of the PLS techniques. Instead of sending the wireless signal everywhere, beamforming entails directing it to a single receiver [1]. This may aid in preventing eavesdropping by users who are not authorized and outside the beamforming range. Artificial noise (AN) injection is another PLS method. To make it more challenging for eavesdroppers to obtain useful information from the wireless signal, AN injection involves injecting random noise into the transmission. This method can help to increase communication link security without the need for any additional encryption or decoding. In order to give a multi-layered approach to security, 5G wireless networks also incorporate additionalsecurity features, including encryption and authentication [2]. These steps combine with PLS to offer a complete security solution that can defend against a variety of attacks. PLS is a crucial component of 5G wireless network security and is necessary to guarantee the security and privacy of user data. PLS is projected to become a more crucial instrument for safeguarding wireless communication networks as the adoption of wireless communication rises. PLS for 5G wireless networks uses a number of other techniques in addition to beamforming and synthetic noise injection [3]. To help ensure that the receiver can correctly decode the message even if some of the bits are corrupted during transmission, channel coding involves adding error-correcting codes to the wireless signal [4]. This can help to ensure data integrity and avoid eavesdropping. The wireless signal is sent using several frequencies during frequency hopping, which involves quick and unpredictable frequency changes. As a result, it would be more challenging for an eavesdropper to concurrently collect the communication on numerous frequencies [5]. Spatial diversity is the process of an eavesdropper that would need to intercept all of the antenna pathways, which can help to increase the communication link's security and reliability. Before transmission, a mathematical change is applied to the wireless signal to help reduce interference and increase the dependability of the communication link. Between the sender and recipient, a safe and dependable communication relationship is established using all of these methods. In order to provide a multi-layered approach to security, 5G wireless networks also use additional security mechanisms such as network slicing, secure boot, and secure element [6]. Big data, connected vehicles, smart cities, and IoT are some of the significant social applications brought on by the launch of 5G and beyond, emphasizing the importance of strong security. Researchers are essential in creating secure solutions that safeguard privacy, secure data, and protect devices from illegal access. The importance of security for broadband and mobile networks drives researchers to improve physical layer security in 5G networks.