A General I- Function Performance Analysis Framework for THz-based 6G Communications

In this paper, we propose a comprehensive performance analysis framework for the general case of multi-path fading channels modeled with a distribution of the form of a generalized I- function that encompasses all other known distributions as special cases. After obtaining the statistics of the received signal's envelope and the signal-to-noise ratio (SNR), we derive closed-form expressions for different performance metrics such as the outage probability, the average bit error probability, and the ergodic capacity. Then, from a practical engineering perspective, we apply our derivations to the case of THz links which are currently under consideration for adoption in the upcoming 6G networks. Revisiting the modeling of these links to align it with the I- function based representation, and taking into consideration other operational and environmental issues such as misalignment and fog, we obtain the expressions of the performance metrics of interest, and we assess the correctness of our derivations by comparison with Monte-Carlo simulation results in two different special cases; namely the classical Nakagami-m fading and the well-adopted α-μ model of the THz channels. The obtained numerical results show perfect match between our analytical framework derivation and the simulations, and provide insights on the impact of many system and environmental parameters, which will be of use to the engineering of THz-based 6G communication systems.