In this letter, we propose new channel characterizations for (1) stochastic Terahertz (THz) communications and (2) reconfigurable intelligent surface (RIS)-aided THz systems. Considering a spherical network with stochastic distances between nodes, we derive the exact closed-form expressions for the probability density function (PDF) and the cumulative distribution function (CDF) of the signal-to-noise ratio (SNR) over the direct link. Using the method of moments, the cascaded channels can be precisely characterized by $\alpha $ - $\mu $ distribution. We show that by using a massive number of reflecting elements, ${M}$ , (e.g., ${M}~\geq $ 4096) the cascaded link actually outperforms the direct THz link in terms of outage probability (OP).

中文翻译：

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RIS 辅助太赫兹通信的信道表征：一种随机方法

在这封信中，我们提出了新的信道特征(1)随机太赫兹 (THz) 通信和(2)可重构智能表面（RIS）辅助太赫兹系统。考虑到节点之间具有随机距离的球形网络，我们推导出直接链路上信噪比 (SNR) 的概率密度函数 (PDF) 和累积分布函数 (CDF) 的精确闭式表达式。使用矩量法，级联通道可以精确地表征为 $\阿尔法$ - $\亩$分配。我们表明，通过使用大量反射元素， ${M}$ , (例如, ${M}~\geq $4096）级联链路在中断概率（OP）方面实际上优于直接太赫兹链路。