Author Archives: Jihan Jihan

ABSTRACT
The fifth generation (5G) mobile communication technology intends to address the massively increasing data rate requirements as well as the massive growth in traffic volume. The 5G technologies achieve higher performance, reduced latency, higher density, and higher mobility minus of sacrificing reliability. However, as the mobile core networks are facing exponential growth in traffic and computing demand as smart devices and mobile applications become more popular. One of the most promising solutions to the challenges is caching. Non-Orthogonal Multiple Access (NOMA) is one of the promising radio access techniques for performance enhancement in next-generation cellular communications. Especially the 5G networks are expected to provide a massively increased number of users at a thousand times higher data rates at lower power consumption because NOMA provides a higher spectral efficiency and higher system throughput. For more improvement, power domain (PD-NOMA), code domain (CD-NOMA) and cooperative (C- NOMA) techniques are proposed and implemented in the 5G to overcome the future network demands. The PD-NOMA, employs Successive Interference Cancellation (SIC) at the receiver and Superposition Coding (SC) at the transmitter.
The proposed systems implemented with the help of MATLAB and NYUSIM simulations. The results of simulation show that the proposed techniques meet the various needs of improved user fairness, quality-of-service (QoS), high reliability, high spectral efficiency, extensive connectivity, raising data rates, high flexibility, low transmission latency, massive connectivity, low delay, higher cell-edge throughput, and superior performance.
For more improvement, caching techniques, as a storing popular reusable information at intermediate nodes to reduce backhauling load in wireless
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networks, have been integrated with C-NOMA to reduce the delay of storing planned content needs, relieve backhaul traffic and to alleviate the delay caused by handovers. The results of simulation of caching integrated with C-NOMA technique have shown promise in maximizing throughput, minimizing latency, and optimizing resource efficiency. In C-NOMA, dynamic resource allocation refers to the process of dynamically modifying the power required to transmit rates and resource blocks allocated to users under their QoS requirements and channel conditions.
Finally, a novel approach is proposed by integrating C-NOMA, massive multiple-input multiple-output (m-MIMO) with caching as a strategic technique to overcome the exponential growth in data demand, spectrum scarcity, mitigation of interference, energy efficiency and sustainability. The simulation and evaluation results proved that the proposed system provides significantly a higher performance in terms of data rate, bit error rate (BER), and outage probability and reduces the power consumption to 52.6% and 54.7% compared to NOMA without cooperative and without NOMA, respectively, which is higher than the related works. The results of simulation verify the achievement of low-latency required by the sixth generation (6G) mobile communication networks cause to operate bandwidth-intensive applications such as high-definition video streaming, augmented reality, virtual reality, and Internet of Things (IoT) devices.

In this dissertation, three nonlinear techniques of prestressing, analysis, and preservation were developed based on the principles of the force method to address geometric nonlinearities in pin-jointed spatial structures. These techniques provide a comprehensive framework for accurately performing prestressing, analysing, and preserving spatial assemblies, validated through rigorous numerical and experimental investigations.

The research introduces direct nonlinear approaches especially for prestressing and preservation, overcoming the limitations of iterative and linear approximation-based methods. The derived nonlinear equations, expressed as functions of joint displacements, were efficiently solved using MATLAB’s fsolve function, demonstrating robust applicability to both simple and complex spatial systems. The proposed prestressing technique computes the desired prestress level by accurately accounting for nonlinear member alterations, preventing cable slack, and maintaining alignment with software solvers under predetermined actuation conditions.

The developed analysis method is efficient and precise, capable of calculating internal member stresses and axial forces for both rigid and flexible members while incorporating geometric nonlinearities under different loading conditions. Similarly, the preservation technique reliably restores disturbed geometries, nodal displacements, and internal forces, with targeted control of specific parameters. The effectiveness of the preservation process depends on actuator placement, bar sensitivity analysis, and the appropriate selection of actuation targets.

Validation of these techniques included numerical case studies and experimental testing on a hyperbolic paraboloid space cable net model with 64 members and 41 joints. The results demonstrated strong agreement, with maximum and minimum discrepancy ratios of 7% and 0%, respectively, between theoretical and experimental measurements. This dissertation presents a novel framework that significantly enhances the precision, efficiency, and control of structural response prediction, making substantial advancements in the field of pin-jointed spatial structures.