In this letter, we analyze ergodic capacity (EC) and outage probability (OP) for threshold-based selective cooperative non-orthogonal multiple access (TBS-C-NOMA) which has been proposed as a reliable alternative to conventional C-NOMA networks. We derive exact expressions for EC and OP in closed-forms and the theoretical analyses are validated via computer simulations. The trade-off for TBS-C-NOMA is raised where the data reliability (i.e., error rate) changes reversely with the EC and OP performances. Nevertheless, it is proved that TBS-C-NOMA provides a remarkable gain in data reliability compared to the decay in EC and OP. Finally, the optimization of power allocation (PA) is re-defined considering the trade-off in TBS-C-NOMA and a joint PA-threshold selection (TS) optimization is proposed in terms of capacity maximization under required data reliability.

中文翻译：

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基于阈值的选择性合作 NOMA：容量/停电分析和联合功率分配-阈值选择优化

在这封信中，我们分析了基于阈值的选择性协作非正交多址接入 (TBS-C-NOMA) 的遍历容量 (EC) 和中断概率 (OP)，TBS-C-NOMA 已被提议作为传统 C-NOMA 网络的可靠替代方案。我们以封闭形式推导出 EC 和 OP 的精确表达式，并且通过计算机模拟验证了理论分析。在数据可靠性（即错误率）随 EC 和 OP 性能反向变化的情况下，提高了 TBS-C-NOMA 的权衡。然而，事实证明，与 EC 和 OP 的衰减相比，TBS-C-NOMA 在数据可靠性方面提供了显着的增益。最后，