Channel Characterization for RIS-Aided Terahertz Communications: A Stochastic Approach

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).