Fixed-Gain AF Relaying for RF-THz Wireless System over $\alpha$-$\kappa$-$\mu$ Shadowed and $\alpha$-$\mu$ Channels

TL;DR

This paper analyzes the performance of fixed-gain AF relaying in RF-THz wireless systems over complex fading channels, providing exact and asymptotic expressions for key metrics and comparing with DF relaying.

Contribution

It introduces a comprehensive analytical framework for fixed-gain AF relaying over $eta$-KMS and $eta$-$ ext{K}$ fading channels, including new PDF and CDF derivations.

Findings

Exact outage probability and BER expressions derived.

Asymptotic analysis reveals high-SNR behavior.

Simulation results compare AF and DF relaying performance.

Abstract

Recent research investigates the decode-and-forward (DF) relaying for mixed radio frequency (RF) and terahertz (THz) wireless links with zero-boresight pointing errors. In this letter, we analyze the performance of a fixed-gain amplify-and-forward (AF) relaying for the RF-THz link to interface the access network on the RF technology with wireless THz transmissions. We develop probability density function (PDF) and cumulative distribution function (CDF) of the end-to-end SNR for the relay-assisted system in terms of bivariate Fox's H function considering $\alpha$-$\mu$ fading for the THz system with non-zero boresight pointing errors and $\alpha$-$\kappa$-$\mu$ shadowed ($\alpha$-KMS) fading model for the RF link. Using the derived PDF and CDF, we present exact analytical expressions of the outage probability, average bit-error-rate (BER), and ergodic capacity of the considered system. We also analyze the outage probability and average BER asymptotically for a better insight into the system behavior at high SNR. We use simulations to compare the performance of the AF relaying having a semi-blind gain factor with the recently proposed DF relaying for THz-RF transmissions.