Design of Double-Hop Relay-Supported Mixed RF-THz Wireless Link

In this paper, we design a double-hop relay-supported mixed RF-THz wireless link utilizing the fixed-gain amplify-and-forward protocol and the decode-and-forward protocol with static source and dynamic relay and destination (relay and destination are taken as unstable drones fluctuating uniformly in yaw and pitch directions). We consider the joint effect of Rayleigh fading and path-loss to model the RF link, and the combined effect of α−µ fading, path-loss, and alignment errors to model the THz transmission link. Precise closed-form analytical expressions for the cumulative distribution function, the probability density function, the characteristic function, and the n-th moment of the end-to-end signal-to-noise ratio of the considered system are obtained in terms of the univariate Fox’s H-function (UFH). Utilizing these expressions, closed-form analytical expressions for the outage probability (OP), average bit error rate (ABER), and average channel capacity (ACC) are obtained in terms of the UFH. To have a better insight into the system performances, we provide an asymptotic analysis for OP and calculate the diversity order of the system in terms of the system and channel parameters. Moreover, the impact of different system and channel parameters on the OP, ABER, and ACC is analyzed.