## 1 Introduction
### Motivations and Contributions
The contention-free FDMA-based FD-MAC protocol offers a fast and straight-forward method of channelization for available bandwidth, but it is unable to handle the large number of UW nodes, resulting in low bandwidth utilization and frequency selective fading problems, resulting in substantial data loss. The contention-free CDMA based FD-MAC protocols (e.g., FH-CDMA, DS-CDMA, and TH-CDMA) have been proposed to address the issues faced by the FD-FDMA based protocols, and showed substantial bandwidth benefits. These protocols, however, have a few minor hardware problems. In contention-based FD-UWAC protocols, users compete with one another for channel access to send their data. The user who wins the contention takes control of the medium for a set period of time, while the others remain silent and wait for a free channel to appear. Contention-based FD-MAC protocols are attractive because of their improved throughput, energy efficiency, and robustness, but these advantages fade as network traffic loads rise, resulting in massive data collision and thus increased energy consumption [35,36]. Handshaking-based and random-access-based FD MACs were proposed to fix these issues. The handshaking-based BD-FD-MAC protocol successfully resolvesthe problem of long propagation delays, which take a long time to complete an effective transmission and reduce FD-MAC protocols throughput efficiency [36]. This protocol has been implemented in a simulation environment; however, it must be implemented in a practical underwater environment. The IBFD-MAC handshaking protocol addresses issues including power consumption, unexpected node collisions, long propagation delays, and low data rates [35]. By resolving the hidden and exposed terminal problem, as well as improving data collision elimination, the hand-shaking DA-CSMA protocol significantly increased performance. The handshaking DA-CSMA protocol significantly improved efficiency, by resolving the hidden and exposed terminal issue, as well as improving data collision elimination. In the future, it will be crucial to test its robustness on a large network, even if it is only implemented for 10 nodes randomly distributed in a square km underwater environment. The handshaking FS-MACA protocol is based on the future scheduling (FS) handshaking (HS) mechanism scheme [37]. Scheduled procedures and future negotiations between the sender and receiving section ensure data transmission in the HS system. The physical channel is split into two parts, one for real data transmission and the other for control packet negotiation, resulting in increased throughput and reduced interference while achieving FD communication. This protocol is unable to handle long propagation delays and suffers from extreme throughput degradation because it does not use time synchronization. The handshaking FDCA-MAC UWAC protocol mentioned in [34] is based on the principle of transmitting and receiving on the same frequency at the same time, which reduces hidden and exposed terminal problems and enables FD-UWAC modems to achieve high throughput. In the future, it will be necessary to test its viability in both a dry and a salty climate. The proposed handshaking-based TFH-MAC protocol significantly reduces SLI, a common issue with FD UWAC systems. When used in a wide network, however, this protocol is unable to handle long propagation delays, resulting in reduced performance. The E-FD-MAC, which is based on handshaking, allows the FD channel to exchange data packets simultaneously in the shortest amount of possible time. This protocol allows the source and destination to exchange data using sensed information without being affected by accidental collisions, resulting in significantly higher throughput and shorter propagation delays [38]. Random access MAC protocols are designed to send and receive data between multiple nodes in a random fashion without any control or HS mechanism.