Performance Analysis of a Dual Terahertz/Ka Band Communication System for Satellite Mega-Constellations

With the rise of satellite mega-constellations, high-data-rate and low-latency space-based internet is set to transform the lives of users in remote locations with no access to the fiber-optic infrastructure. While current commercial constellations are relying on microwaves, they are legally and technologically limited to only a few gigahertz of bandwidth, paralyzing the potential for ultra high data rate performance. In this paper, a dual terahertz/Ka-band communication system is proposed and studied as a solution. A space-Earth propagation model based on the International Telecommunication Union most recent recommendations is presented, and a mega-constellation of 8,320 small satellites in low Earth orbit is designed to test the dual-band performance for the uplink, downlink, and crosslink. Extensive simulations are performed using an in-house-developed orbital simulation tool to calculate data rates for each terahertz and Ka band links based on signal-to-noise ratio estimates with dynamic decision making to constantly provide the highest data rate possible. For links between Earth and space, the results show similar performance for terahertz and Ka-band communications, while terahertz significantly outperforms in inter-satellite links. Simulation results show that terahertz communication can be a good candidate for space-Earth and inter-satellite links as both an enhancement to existing microwave technology and as a stand-alone technology with the identified challenges addressed.