With the increasing requirements for efficient utilization of satellite resources, both non-orthogonal multiple access (NOMA) scheme and cognitive radio (CR) have been recognized as one of the promising solutions, particularly, for the enhancement of spectrum efficiency. This letter investigates the performance of NOMA-based integrated satellite-terrestrial relay network (ISTRN) in the presence of multiple primary users (PUs) under spectrum sharing environment. Specifically, we derive the closed-form expressions of outage probability (OP) and ergodic capacity (EC) of the considered system under the interference constraint imposed by multiple adjacent PUs. To get further insights, the asymptotic analysis for OP at high signal-to-noise ratios (SNRs) is also obtained. Numerical results are provided to verify our analysis and reveal the impacts of key parameters on system performance.

中文翻译：

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频谱共享环境下基于NOMA的星地综合中继网络

随着对卫星资源高效利用的要求不断提高，非正交多址（NOMA）方案和认知无线电（CR）已被公认为有前景的解决方案之一，特别是在提高频谱效率方面。这封信调查了在频谱共享环境下存在多个主要用户 (PU) 的情况下基于 NOMA 的综合卫星地面中继网络 (ISTRN) 的性能。具体来说，我们推导出了在多个相邻 PU 施加的干扰约束下所考虑系统的中断概率 (OP) 和遍历容量 (EC) 的闭式表达式。为了获得进一步的见解，还获得了高信噪比 (SNR) 下 OP 的渐近分析。