Toward the Internet of Space Things: Performance Analysis of LEO Satellite Relay Networks using mmWave and sub-THz links

2026-05-03

AI Summary

This work addresses the critical limitation of existing ground stations in supporting high-bandwidth, continuous communication with Low Earth Orbit (LEO) CubeSats, which currently suffer from mere minutes of daily contact windows. The authors propose a LEO relay backbone network leveraging millimeter-wave and sub-terahertz inter-satellite links, integrating time-varying orbital dynamics with high-frequency channel modeling to establish a comprehensive performance analysis framework. They demonstrate for the first time that global 24/7 coverage can be achieved with only ten relay satellites and derive a fundamental upper bound on downlink capacity. Compared to conventional ground station networks, the proposed system improves throughput, connectivity availability, and energy efficiency by several orders of magnitude, substantially enhancing contact probability and channel capacity.

Abstract

As the commercial space economy expands, existing ground-based infrastructure faces severe bottlenecks in supporting the data-intensive continuous connectivity needs of next-generation "space users," including CubeSats, space data centers, and more. Even when utilizing existing Ku-band ground relay networks, the contact time with a CubeSat at low-Earth orbit (LEO) is often still limited to minutes per day only. This paper analyzes an alternative system design that leverages emerging high-rate millimeter-wave (mmWave) and sub-terahertz (sub-THz) inter-satellite links to build a high-throughput and high-availability satellite-based relay backbone for space vehicles. To evaluate this concept, we develop a comprehensive mathematical framework that jointly incorporates complex time-variant orbital dynamics and mmWave/sub-THz link characteristics. We then derive the key performance indicators, including contact probability, channel capacity, and energy efficiency. The numerical results, cross-verified by computer simulations, demonstrate that such systems can provide improvements of up to several orders of magnitude compared to existing networks of ground stations. Notably, we identify a fundamental bound on download capacity and show that continuous 24/7 connectivity becomes achievable with only ten LEO relay satellites. These findings establish mmWave and sub-THz satellite relay networks as a promising, scalable, and energy-efficient solution, thus unlocking improved connectivity with various space vehicles of tomorrow.

Problem

• Internet of Space Things
• LEO satellite relay networks
• mmWave
• sub-THz
• continuous connectivity

Innovation

• mmWave
• sub-THz
• LEO satellite relay
• inter-satellite links
• space connectivity