Impacts of sampling on the artificial noise-assisted terahertz secure communication systems

In this paper, we investigate an artificial noise (AN)-assisted terahertz (THz) secure communication system. Different from previous studies, we consider a non-ideal analog-to-digital converter (ADC) in the AN-THz system. Specifically, both synchronization noise and quantization noise in ADC are investigated. The normalized distortion matric is employed to calculate synchronization noise power and the Bellman’s theory is introduced for quantization noise power. Under the constrain of limited ADC power, the secrecy performance presents a ‘U-shaped’ curve versus the sampling rate and therefore the optimal sampling rate is derived. Moreover, we validate our theoretical model in the experiment, and our experimental results in 102 GHz show the synchronization noise power varies with the square of timing error, and the quantization noise power is affected by the total data length, which agree well with the model predictions.