发表机构
Indian Institute of Technology Goa; Indian Institute of Technology Guwahati; University of Essex; Indian Institute of Technology (BHU)（印度果阿理工学院; 印度古瓦哈提理工学院; 埃塞克斯大学; 印度理工学院（贝拿勒斯印度教大学））
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文针对OFDM速率分裂SCMA系统，分析CFO损伤下的BER性能，提出有限字母表分析框架，揭示CFO导致高SNR BER底限且私有层受损更重，仿真验证了准确性。
AI 中文摘要
速率分裂稀疏码多址接入（RS-SCMA）在同一资源元素上叠加了QAM调制的公共消息和SCMA编码的私有消息。本文分析了在频率选择性瑞利衰落信道上，存在载波频率偏移（CFO）时基于正交频分复用（OFDM）的RS-SCMA的误码率（BER）性能。针对公共层检测、连续干扰消除（SIC）和私有层SCMA检测，开发了一个有限字母表BER框架。所提出的分析明确保留了公共层和私有层的信号分量，并使用其条件二阶统计量，将未解决的块内和块间CFO泄漏建模为条件高斯干扰。还考虑了由错误公共层消除引起的残余干扰以及可调消息分裂因子的影响。结果表明，CFO会产生高信噪比下的BER底限，该底限随归一化频率偏移的增加而升高。在所考虑的条件下，过载的SCMA私有层受到更严重的影响，并主导整体BER。完美SIC的仿真进一步表明，消除公共层决策错误对私有层BER底限的影响微乎其微，这表明主要的性能退化源于CFO损伤的私有层检测，而非SIC错误传播。蒙特卡洛仿真验证了所推导的BER表达式，并证明了其在所考虑的CFO范围内准确捕获逐层和整体BER性能的能力。
英文摘要
Rate-splitting sparse code multiple access (RS-SCMA) superimposes QAM-modulated common messages and SCMA-encoded private messages over the same resource elements. This paper analyzes the bit error rate (BER) performance of orthogonal frequency division multiplexing (OFDM)-based RS-SCMA in the presence of carrier frequency offset (CFO) over frequency-selective Rayleigh fading channels. A finite-alphabet BER framework is developed for common-layer detection, successive interference cancellation (SIC), and private-layer SCMA detection. The proposed analysis explicitly retains the common and private-layer signal components and models the unresolved intra- and inter-block CFO leakage as conditionally Gaussian interference using its conditional second-order statistics. Residual interference caused by erroneous common-layer cancellation and the effect of a tunable message-splitting factor are also incorporated. The results show that CFO produces a high-SNR BER floor that increases with the normalized frequency offset. Under the considered conditions, the overloaded SCMA private layer is more severely affected and dominates the overall BER. Simulations with perfect SIC further show that eliminating common-layer decision errors has only a marginal impact on the private-layer BER floor, indicating that the dominant degradation arises from CFO-impaired private-layer detection rather than SIC error propagation. Monte Carlo simulations validate the derived BER expressions and demonstrate their accuracy in capturing the layer-wise and overall BER performance over the considered CFO range.
