Analyzing Bit Error Rate Performance in Downlink Cooperative NOMA Systems with Various Modulation Techniques across Varied Fading Channels

Incorporating cooperative communication into Non-Orthogonal Multiple Access (NOMA) networks, known as cooperative NOMA, is driven by the goal of enhancing network scalability while maintaining fair resource allocation. This approach seeks to enhance the efficiency of NOMA-based networks by leveraging cooperative strategies among users, thereby enabling fair allocation of network resources. This study investigates the performance of cooperative NOMA in comparison to alternative techniques, particularly focusing on far and near user scenarios. The research explores various nonfading and fading methods in conjunction with different modulation schemes to assess the Bit Error Rate (BER) in far and near user NOMA setups. Specifically, comparisons are made among BPSK, QPSK, and 16QAM modulation techniques, considering the impact of Additive White Gaussian Noise (AWGN) channels. Additionally, the study extends its analysis by employing BPSK and QPSK schemes across different fading channels, including Rayleigh, Rician, log-normal, and Weibull channels. The BER performance is evaluated concerning transmit power for both far and near user NOMA configurations. Using MATLAB simulations, BER performances are evaluated, and a comparative examination of BER under various environments is provided.