Large intelligent surface (LIS) has recently emerged as a potential enabling technology for 6G networks, offering extended coverage and enhanced energy and spectral efficiency. In this work, motivated by its promising potentials, we investigate the error rate performance of LIS-assisted nonorthogonal multiple access (NOMA) networks. Specifically, we consider a downlink NOMA system, in which data transmission between a base station (BS) and L NOMA users is assisted by an LIS comprising M reflective elements (REs). First, we derive the probability density function (PDF) of the end-to-end wireless fading channels between the BS and NOMA users. Then, by leveraging the obtained results, we derive an approximate expression for the pairwise error probability (PEP) of NOMA users under the assumption of imperfect successive interference cancellation. Furthermore, accurate expressions for the PEP for M = 1 and large M values ( M > 10) are presented in closed-form. To gain further insights into the system performance, an asymptotic expression for PEP in high signal-to-noise ratio regime, asymptotic diversity order, and tight union bound on the bit error rate are provided. Finally, numerical and simulation results are presented to validate the derived mathematical results.

中文翻译：

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6G 网络大型智能表面辅助非正交多址接入：性能分析


大型智能表面 (LIS) 最近已成为 6G 网络的潜在支持技术，可提供更大的覆盖范围并提高能源和频谱效率。在这项工作中，受其巨大潜力的推动，我们研究了 LIS 辅助的非正交多址 (NOMA) 网络的错误率性能。具体地，我们考虑下行链路NOMA系统，其中基站（BS）和L个NOMA用户之间的数据传输由包括M个反射元件（RE）的LIS辅助。首先，我们推导出 BS 和 NOMA 用户之间的端到端无线衰落信道的概率密度函数 (PDF)。然后，利用所获得的结果，我们在不完美连续干扰消除的假设下推导了 NOMA 用户的成对错误概率（PEP）的近似表达式。此外，M = 1 和大 M 值 ( M > 10) 的 PEP 的准确表达式以封闭形式呈现。为了进一步了解系统性能，提供了高信噪比状态下的 PEP 渐近表达式、渐近分集阶数以及误码率的紧并界。最后，给出了数值和模拟结果以验证所得出的数学结果。