Investigating the bit error rate performance of the mimo-noma network with majority-based TAS/MRC scheme

This thesis focuses on examining the performance of downlink MIMO-NOMA networks using the TAS-maj/MRC technique. It addresses the limitations of previous studies and explores the advantages of combining NOMA and MIMO technologies. Previous research has mainly focused on evaluating SISO NOMA networks and has overlooked the error rate performance of MIMO-NOMA systems. Finding an optimal transmit AS solution remains a challenge in NOMA networks. To overcome these limitations, this thesis makes significant contributions. Firstly, it investigates the bit error rate (BER) performance of the downlink MIMO-NOMA network with the TAS-maj/MRC scheme under the Nakagami-m fading channel model. By considering the Nakagami-m fading model, which better represents real-world fading channel conditions, a more accurate assessment is achieved. The thesis provides an exact closed-form expression for the BER, offering insights into the system's performance. Additionally, asymptotic analysis is conducted in high signal-to-noise ratio (SNR) regions to evaluate the diversity and array gains achieved by the TAS-maj/MRC scheme. This analysis enhances our understanding of the system's behavior and the benefits of employing the TAS-maj/MRC scheme in MIMO-NOMA networks. Theoretical results are validated through extensive Monte Carlo simulations, demonstrating significant BER improvements with increasing receive antennas and improved channel conditions. The research findings contribute to a comprehensive understanding of the BER performance of MIMO-NOMA systems with the TAS-maj/MRC scheme under various channel conditions. This understanding is valuable for the design and optimization of practical wireless communication applications. By identifying the limitations of MIMO-NOMA systems and proposing strategies to enhance their performance, this research aims to advance wireless communication systems. The thesis structure is as follows: Chapter 1 provides an overview of OMA radio access techniques, introduces NOMA concepts in downlink and uplink networks, and discusses the emergence of MIMO-NOMA systems. Chapter 2 presents a literature review, analyzing previous research on MIMO-NOMA systems, emphasizing the need to investigate the error rate performance. Chapter 3 describes the theoretical framework of the MIMO-NOMA system with the TAS-maj/MRC scheme, including the Nakagami-m fading channel model, transmit AS schemes, and MRC on the receiver side. The derivation of the closed-form expression for the BER is explained in detail. Chapter 4 presents simulation results and analyzes the BER performance under different channel conditions. Various parameters, such as receive antennas and channel conditions, are examined through Monte-Carlo simulations, confirming the improvements in BER performance and validating the theoretical findings. Finally, We summarize the research findings, discuss the study's contributions, and suggest directions for future research. The summary highlights the significance of this research in bridging the gap between NOMA and MIMO technologies, exploring the benefits of the TAS-maj/MRC scheme in MIMO-NOMA networks, and providing insights into the system's behavior under different channel conditions.