###### Abstract
HNOMA acts as a simple two-UE NOMA system within every sub-frame. Therefore, the degradation of performance due to iSIC and HWDs is compensated for and, indirectly, HNOMA reduces the SIC error propagation. Through the NOMA phenomenon, larger power is allocated to weaker UE (WUE), and the remaining small power fraction is given to stronger UE (SUE) to maintain fairness. However, to support the quality of service (QoS) of each UE, the power allocation (PA) has to be optimized. Despite giving large power to the WUE, there exists a degradation in WUE performance. This is due to the weaker link between next-generation NodeB (gNB) and cell-edge UE. Cooperative NOMA (C-NOMA) utilizes the natural synergy within NOMA. In this approach, the SUE decodes the WUE's data and relays them, providing signal diversity [7]. This dual-link transmission significantly enhances the performance of the WUE in the system. This results in diversity gain without requiring additional antennas, as seen in multi-input multi-output (MIMO) systems. Furthermore, cooperative relaying can effectively extend the coverage area of the gNB, ensuring more reliable and extensive communication with enhanced outage probability and throughput performance, especially for UE with poor channel conditions [8; 9]. However, the SUE has to perform a retransmission to the WUE. This requires large power from the SUE, which eventually drains the SUE's battery. During the integration of reconfigurable intelligent surfaces (RISs) during retransmission/cooperative relaying, the SUE does not require much power, and it can also reach cell-edge UE and UE at dead zones with the least power [10; 11]. RISs are capable of dynamically manipulating electromagnetic waves to enhance signal quality and coverage [12; 13]. However, their limitation lies in their half-space coverage, which restricts their effectiveness in environments requiring comprehensive signal reach. In contrast, intelligent omni-surfaces (IOSs) overcome this drawback by offering full space coverage, ensuring seamless connectivity in all directions [13; 14]. IOSs offer comprehensive coverage by reflecting and refracting signals omnidirectionally, unlike RISs, which direct signals in one way. This enhances network flexibility, especially in complex environments, enabling seamless communication for multiple users both indoors and outdoors. While RISs may cause dead zones, IOSs ensure effective signal transmission and adapt to varied situations using multipath propagation, boosting coverage and reliability. It maintains strong link stability by adjusting to environmental changes, critical in highly mobile or obstructed areas. Although RISs perform well in controlled environments, it struggles in dynamic, crowded spaces requiring real-time adjustments. This expansive coverage makes the IOS more suitable for complex and dynamic communication scenarios, providing a more versatile and reliable solution for future wireless networks [15; 16]. IOSs offer several advantages over RISs, making it a promising technology for future wireless communication systems. However, IOS also presents certain challenges, including self-interference caused by multipath effects, coupling losses, and non-linear distortions [17]. These interferences can lead to power leakage, correlated interference, and constructive or destructive interference, ultimately degrading overall system performance. To mitigate these challenges, IOS component design can be optimized with high-isolation architectures to minimize mutual coupling effects. Advanced signal processing techniques at the radio frequency (RF) chains, such as RF cancellation using analog circuits, can effectively reduce correlated interference [18]. Additionally, integrating hybrid active-passive IOS components with adaptive filters within the architecture can help compensate for losses due to non-linear distortions, enhancing overall system efficiency and reliability [19].