Maximal Selective Transmit Diversity for Petahertz Wireless Communications with Continuous Waveform Detector

Abstract

Motivated by unique atmospheric scattering properties of optical waves at petahertz frequencies, we present a novel maximal selective transmit diversity scheme based on the selection of maximum irradiance optical path with a continuous waveform detector employed for petahertz wireless communications. The proposed scheme is designed to significantly improve the performance of a non-line-of-sight (NLOS) petahertz link in a turbulence-induced fading channel. We characterize the received signal by a continuous wave detector and quantify the cumulative distribution function (CDF) of the largest order statistics of the received irradiance. Furthermore, we derive closed-form expressions of important performance metrics including the average bit error rate, the outage probability, and the optical channel capacity with each scattered path experiencing the Gamma-Gamma distributed turbulence-induced fading. From the analytical expressions derived, the performance of the proposed NLOS petahertz communication system is analyzed and validated. Simulation results show that the proposed scheme effectively overcomes the channel impairment without increasing the transmit power. Even under strong turbulence fading, when the number of transmit diversity branches increases from 1 to 2 and 4, the required average signal-to-noise ratio (SNR) to maintain an outage probability of 10-5 is found to be significantly reduced by 13 dB and 21 dB, respectively.