Satellite-based Internet of Things (S-IoT) is regarded as an effective solution to enable ubiquitous connectivity in a global coverage and cost-effective manner for massive machine type communications (mMTC) in the future Internet of Things. In this article, we propose a superimposed pilots code domain nonorthogonal multiple access over a shadowed-Rician fading and path loss satellite-ground channel model in uplink mMTC S-IoT system. First, we analyze the interference due to the collision in the random access scenario, and propose an iteration channel estimation based on ridge regression algorithm to attain a more precise channel state information. Moreover, we utilize successive interference cancellation (SIC) and successive joint decoding (SJD) to recover the singleton user equipments. Then, we derive the expressions of the outage probability and maximum system throughput of SP scheme, and compared with the regular orthogonal pilot (RP) scheme under SIC and SJD, respectively. Simulations validate our analytical results and show that the achievable system throughput of the SP scheme under SJD can outperform that of the RP scheme in a S-IoT system for short packet transmission.

中文翻译：

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星基物联网叠加引导码域NOMA方案

基于卫星的物联网（S-IoT）被认为是未来物联网中大规模机器类型通信（mMTC）以全球覆盖和具有成本效益的方式实现无处不在连接的有效解决方案。在本文中，我们在上行链路 mMTC S-IoT 系统中的阴影-莱斯衰落和路径损耗卫星-地面信道模型上提出了一种叠加导频码域非正交多址。首先，我们分析了随机接入场景中碰撞引起的干扰，并提出了一种基于岭回归算法的迭代信道估计，以获得更精确的信道状态信息。此外，我们利用连续干扰消除（SIC）和连续联合解码（SJD）来恢复单例用户设备。然后，我们推导出SP方案的中断概率和最大系统吞吐量的表达式，并分别与SIC和SJD下的规则正交导频(RP)方案进行比较。仿真验证了我们的分析结果，并表明 SJD 下 SP 方案可实现的系统吞吐量在短数据包传输的 S-IoT 系统中优于 RP 方案。