### Related Work
(CSI), Rayleigh fading and Nakagami-m fading channel for concluding the proposed approach. For reliability and security of a system with multi-antenna users and eavesdropper, single antenna source and Nakagami-m fading channel, an imbalance in-phase and quadrature component [20] is explored for its influence on the system. An Artificial Noise (AN)-aided cooperative communication scheme with relay firing the jamming signal [21] is proposed, where the ergodic secrecy sum-rate (ESSR) is used to evaluate the system secrecy performance. For improving sum data rate, an opportunistic relay selection scheme [22] is employed and several wireless communication techniques are used to support the system. A resource allocation problem [23] for an interplay of NOMA, FD and D2D are proposed for sum-rate optimization where a group of strong users assist weak legitimate users. IBFD can improve conventional wireless communication in terms of time delay, loss of data due to high congestion, hidden terminals and SE. This is to develop a heterogeneous dense network with high capacity and flexible relaying nodes. The quantitative analysis of theoretical and practical deployment shows that at the cost of increased complexity, FD shows high throughput, diversity, low symbol error rate and reduce the use of conventional HD. Alongside interference and security management, the proposed R-IBFD poses the above benefits. The large buffer size for FD devices can additionally reduce the Packet-Loss-Ratio (PLR) [24]. The D2D FD communication performance increases with the increase of in-cell communication ratio that leads to bandwidth efficiency [25]. The IBFD deployment needs new algorithms for the deployment of 6G. It aims to use high-frequency bands like millimetre waves (mmWaves). This is because the low-frequency spectrum is fully utilized with the existing below 5G systems. To prevent the use of high frequencies, harmful for the health, it is better to reuse the spectrum with FD or NOMA for higher SE and better utilization of lower frequency bands. NOMA offers a high bandwidth efficiency when implemented with IBFD. There are several types of NOMA. Categorically, power domain NOMA and code domain NOMA are the two major divisions. This paper focuses on the power domain NOMA with IBFD. This paper elaborates the problems, solutions, benefits and challenges offered for power domain NOMA. In NOMA, the power is allocated with respect to the distance and the channel condition of the individual user, in the same frequency band. The user far from the transmitter needs the highest power allocation. The power allocation decreases with the distance and the improvement of the channel condition. The transmitter superposes signals of all users before transmission. The sum of all user's power coefficients is always equal to 1. \(\alpha_{1}+\cdots+\alpha_{N}=1\), where \(\alpha\) is the coefficient of power allocation and N is the total number of user/s. At each receiving node, the nearest strong users need to do Successive Interference Cancellation (SIC) for all users' signals that have power higher than its own signal. Similarly, other users decode their signals. The furthest weak user does not receive the high power signals of other users; therefore, it considers the power of others users with the better channel conditions as noise to decode its own signal [26]. Amongst many problems of NOMA, strong interference, SIC complexity and the use of high-power allocation are the major problems. Installation of the NOMA algorithm requires high computational power for both real-time power allocation and successive interference cancellation. The new technologies such as IoT, Multiple Input and Multiple Output (MIMO), high-speed web, interactive multimedia processing and TV streaming also require energy consumption. Normal battery life for integrating the technologies in 6G will not be sufficient. There are a number of possible proposed solutions to overcome the interference and to maintain the balance in the system in terms of high-power allocation requirements.