论文标题
STBC辅助协作NOMA具有正时偏移，连续的干扰取消和不完美的渠道状态信息
STBC-Aided Cooperative NOMA with Timing Offsets, Imperfect Successive Interference Cancellation, and Imperfect Channel State Information
论文作者
论文摘要
非正交多重访问（NOMA）和合作通信的组合可以是第五代（5G）和超过5G（B5G）无线系统的合适解决方案，因为它可以提供较高的频谱效率，较低的能量消耗，并且与非合作性Noma相比，它可以提供较高的频谱效率，并提高了公平性。但是，由于每个用户的连续干扰取消（SIC），常规合作NOMA中的接收器复杂性随用户数量的增加而增加。与常规合作NOMA相比，时空块代码辅助协作NOMA（STBC-CNOMA）提供的SIC数量较少。在本文中，我们在实际挑战中评估了STBC-CNOMA的性能，例如不完美的SIC，分布式合作用户之间的不完美的时正时同步，以及不完美的渠道状态信息（CSI）。在存在这种逼真的障碍的情况下，我们得出接收信号的封闭形式表达式，然后使用它们来评估停运概率。此外，我们通过高发射信号噪声比以渐近分析来提供直观的见解，以了解每种损伤对中断性能的影响。我们还将STBC-CNOMA的复杂性与给定数量用户的现有合作NOMA协议的复杂性进行了比较。此外，通过分析和仿真，我们观察到与其他两个缺陷相比，不完美的SIC对STBC-CNOMA中断性能的影响更为重要。因此，考虑到与其他合作NOMA方案相比，STBC-CNOMA的SIC数量较少，因此STBC-CNOMA是一种有效的解决方案，可在相同的SIC缺陷条件下获得高可靠性。
The combination of non-orthogonal multiple access(NOMA) and cooperative communications can be a suitable solution for fifth generation (5G) and beyond 5G (B5G) wireless systems with massive connectivity, because it can provide higher spectral efficiency, lower energy consumption, and improved fairness compared to the non-cooperative NOMA. However,the receiver complexity in the conventional cooperative NOMA increases with increasing number of users owing to successive interference cancellation (SIC) at each user. Space time block code-aided cooperative NOMA (STBC-CNOMA) offers less numbers of SIC as compared to that of conventional cooperative NOMA. In this paper, we evaluate the performance of STBC-CNOMA under practical challenges such as imperfect SIC, imperfect timing synchronization between distributed cooperating users, and imperfect channel state information (CSI). We derive closed-form expressions of the received signals in the presence of such realistic impairments and then use them to evaluate outage probability. Further, we provide intuitive insights into the impact of each impairment on the outage performance through asymptotic analysis at high transmit signal-to-noise ratio. We also compare the complexity of STBC-CNOMA with existing cooperative NOMA protocols for a given number of users. In addition, through analysis and simulation, we observe that the impact of the imperfect SIC on the outage performance of STBC-CNOMA is more significant compared to the other two imperfections. Therefore, considering the smaller number of SIC in STBC-CNOMA compared to the other cooperative NOMA protocols, STBC-CNOMA is an effective solution to achieve high reliability for the same SIC imperfection condition.
