Satellite communication systems: the future of 5G/6G connectivity

Higher Education Press

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ISL: inter-satellite link; gNB: next-generation NodeB.

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Credit: Afang Yuan, Zhihua Yang, Zhili Sun

The integration of satellite communication systems with terrestrial networks is emerging as a crucial solution to achieve seamless global connectivity in the evolving landscape of 5G and future 6G networks. A recent article published in Engineering titled “Evolution of Satellite Communication Systems Toward 5G/6G for 2030 and Beyond” provides a comprehensive overview of the advancements, challenges, and future directions in this domain.

 

According to the article, terrestrial networks (TNs) have made significant strides from 1G to 4G, and now 5G, in increasing communication speeds and improving quality of service. However, these networks face limitations in remote or sparsely populated areas due to geographical constraints, high deployment costs, and insufficient bandwidth. This is where satellite communication systems come into play, offering a promising solution to provide global coverage, low latency, and high throughput.

 

The authors highlight that satellite networks are becoming an integral part of future 5G/6G systems, combining with TNs to form a unified communication infrastructure. Satellites at various orbital altitudes—geostationary Earth-orbit (GEO), medium-Earth-orbit (MEO), and low-Earth-orbit (LEO)—serve different roles, such as access, forwarding, and relay nodes. For instance, GEO satellites are suitable for fixed satellite services with high latency, while LEO satellites offer low latency and are ideal for global broadband access and Internet of Things (IoT) connectivity.

 

Significant advancements have bridged the gap between satellite communication and TNs. High-throughput satellites, mega-constellations in LEO, and improved payloads with beamforming and onboard processing have reduced latency and increased capacity. The development of inter-satellite links (ISLs), particularly optical ISLs, has also been a game-changer, offering higher data rates and better interference immunity. However, challenges remain, including high deployment costs and the need for precise beam alignment in large-scale constellations.

 

The article also discusses the role of international standardization bodies such as the 3rd Generation Partnership Project (3GPP) and International Telecommunication Union (ITU) in facilitating the integration of satellite networks with TNs. 3GPP has released a series of technical reports and specifications to support  non-terrestrial network (NTN) integration, with each release progressively enhancing the capabilities of satellite systems within 5G and future networks. For example, Release 17 marked the first time NTNs were incorporated as a core element within the 5G system architecture, supporting features like direct-to-device satellite links and IoT applications.

 

Looking ahead, the authors identify key challenges and potential research directions for satellite communication systems in 5G/6G. These include managing long propagation delays, high Doppler shifts, efficient resource management, dynamic beam coverage adaptation, mobility and handover management, and optimal routing and path selection. Future research may focus on leveraging technologies such as AI-driven network management, direct smartphone access to satellites, mega-LEO constellations, spectrum sharing, optical wireless communication, and reconfigurable intelligent surfaces.

 

The integration of satellite communication systems with terrestrial networks is a significant trend in the evolution from 5G to 6G. As research and development continue, addressing the identified challenges will be crucial to realizing the full potential of seamless global connectivity for future communication networks.

 

The paper “Evolution of Satellite Communication Systems Toward 5G/6G for 2030 and Beyond,” is authored by Afang Yuan, Zhihua Yang, Zhili Sun. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.06.025. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.

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Journal

Engineering

DOI

10.1016/j.eng.2025.06.025 

Article Title

Evolution of Satellite Communication Systems Toward 5G/6G for 2030 and Beyond

Space computing power networks: a new frontier for satellite technologies

Higher Education Press

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The Space-CPN architecture.

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Credit: Linling Kuang, Yuanming Shi, Kai Liu, Chunxiao Jiang

In the rapidly evolving landscape of satellite technologies, a novel concept known as space computing power networks (Space-CPN) is emerging as a potential solution to address the growing demands for efficient data processing and transmission in space-based applications. A recent article published in Engineering titled “Space Computing Power Networks: Fundamentals and Techniques” delves into the intricacies and potential of Space-CPN, highlighting its ability to integrate communication and computation capabilities across various types of satellites.

 

Over the past few decades, satellite technologies have made significant strides, enabling seamless global connectivity and extensive data collection through remote sensing. However, traditional methods of downloading raw data from satellites for further processing on the ground face several challenges, including short visible windows for satellite–ground communication, high-frequency band limitations, and privacy concerns. To overcome these hurdles, Space-CPN has been proposed as a promising architecture that leverages advanced edge computing techniques and onboard computing payloads to empower fast and trustworthy onboard information processing.

 

Space-CPN expands the concept of computing power networks by incorporating innovations in satellite networks. It integrates the communication and computation capabilities of low-Earth-orbit (LEO), medium-Earth-orbit (MEO), and geostationary-Earth-orbit (GEO) satellites, allowing for flexible scheduling of computing power to achieve secure, fast, and accurate onboard intelligent data processing. For instance, GEO/MEO/LEO satellites can serve as space computing centers for emergency scenarios, while ground stations act as terrestrial computing centers for high-demand computing tasks.

 

The development of Space-CPN faces several key challenges. One lies in the design of communication principles that can support specific computation tasks, shifting from traditional data-oriented transmission to task-oriented communication. The article introduces the robust information bottleneck (RIB) principle, which aims to maximize the mutual information between the result and the label of the data sample for accuracy, while minimizing the mutual information between the feature and the input sample for compression. This approach enhances communication robustness without additional overhead.

 

Another challenge is the onboard computing architecture, where limited energy resources necessitate low-power solutions. Neuromorphic computing, which mimics the human brain’s integrated memory and processing capabilities, is highlighted as a potential solution. The article discusses the application of spiking neural networks (SNNs) and proposes satellite federated and decentralized neuromorphic learning network architectures to enable efficient onboard training.

 

Resource allocation in Space-CPN is also a critical issue, given the dynamic and uncertain nature of space networks. The article proposes robust optimization methods, including robust reinforcement learning for satellite microservice deployment and distributionally robust optimization for satellite task scheduling. These methods aim to quantify the relationship between computation task requirements and network resources, ensuring efficient utilization in highly dynamic environments.

 

Space-CPN represents a significant step forward in the integration of communication and computation in space networks. By addressing the challenges of task-oriented communication, energy-efficient computing architectures, and robust resource allocation, Space-CPN has the potential to revolutionize how data is processed and transmitted in space-based applications, paving the way for more efficient and intelligent satellite systems.

 

The paper “Space Computing Power Networks: Fundamentals and Techniques,” is authored by Linling Kuang, Yuanming Shi, Kai Liu, Chunxiao Jiang. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.06.026. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.

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Journal

Engineering

DOI

10.1016/j.eng.2025.06.026 

Article Title

Space Computing Power Networks: Fundamentals and Techniques

 

Tunnel resilience models unveiled to aid post-earthquake recovery

Higher Education Press

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Resilience models for post-hazard recovery of tunnels.

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Credit: Zhong-Kai Huang, Nian-Chen Zeng, Dong-Mei Zhang, Sotirios Argyroudis, and Stergios-Aristoteles Mitoulis

A new study published in Engineering presents novel resilience models for assessing and quantifying the recovery of tunnels after earthquakes. The research, conducted by a team from Tongji University, Brunel University of London, and University College London, offers a probabilistic approach to predict tunnel recovery, providing valuable insights for infrastructure operators and city planners.

 

Tunnels are critical components of urban infrastructure, continuously exposed to various hazards, including earthquakes, fires, floods, and aging-related disturbances. Events such as the magnitude-7.8 earthquake in southeastern Türkiye in 2023 and the Chi-Chi earthquake in Taiwan of China have caused significant damage to tunnels, highlighting the vulnerability of these structures and the need for robust resilience assessment tools. Previous research has extensively explored the vulnerability and fragility of tunnels, but studies focusing on restoration to quantify resilience have been limited. This gap has hindered proactive and reactive adaptation measures to ensure seamless tunnel functionality.

 

To address this issue, the study introduces a damage-level-dependent probabilistic approach for quantifying tunnel recovery. The research team conducted a global expert survey to gather input on restoration tasks, their duration, sequencing, and cost. The survey focused primarily on damage induced by seismic events, incorporating idle times and traffic capacity gains over time. The results were used to generate deterministic and probabilistic reinstatement and restoration models, with the probabilistic models accounting for epistemic uncertainties.

 

The study proposes a framework for assessing tunnel resilience, which includes hazard characterization, vulnerability assessment, and the development of restoration models. The framework is based on defining structural damage levels and using fragility functions to determine the probability of damage at a given hazard intensity. The restoration models are tailored to tunnel resilience assessments, incorporating expert knowledge on required restoration tasks and their prioritization. The models help quantify resilience and optimize the repair process for tunnels with various levels of damage.

 

The research highlights that the most time-consuming restoration tasks typically involve replacing tunnel structural components or reinforcing tunnel structures and soil. The study also finds that idle time and cost ratios increase significantly with greater damage severity. For example, the mean idle time for tunnels with minor, moderate, extensive, and complete damage levels were found to be 6.52, 12.09, 24.02, and 50.57 days, respectively. The cost ratio, which represents the restoration cost relative to the total construction cost, also rises with increasing damage severity, ranging from 7.73% for minor damage to 74.05% for complete damage.

 

The study’s findings are demonstrated through a case study of a typical tunnel, showing how the newly developed restoration models can be applied to assess tunnel resilience. The results indicate that the resilience index of the tunnel decreases as seismic intensity increases, with more severe damage levels corresponding to longer restoration times and higher uncertainty in the resilience index.

 

The research underscores the importance of incorporating resilience models into post-earthquake restoration workflows, guiding practitioners in optimal decision-making. The models provide a scientific basis for estimating downtime and losses due to tunnel disruptions, facilitating proactive tunnel adaptation and resource allocation. Future research is suggested to enhance the reliability and generalizability of the restoration models by collecting more expert responses and incorporating parameters tailored to specific tunnel designs and conditions.

The paper “Resilience Models for Tunnel Recovery After Earthquakes,” is authored by Zhong-Kai Huang, Nian-Chen Zeng, Dong-Mei Zhang, Sotirios Argyroudis, and Stergios-Aristoteles Mitoulis. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.06.028. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.

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Journal

Engineering

DOI

10.1016/j.eng.2025.06.028 

Article Title

Resilience Models for Tunnel Recovery After Earthquakes

 

URI researchers uncover molecular mechanisms behind speciation in corals

Findings shed light on the origins of species on coral reefs driven by eye related genes

University of Rhode Island

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Matías Gómez-Corrales, a recent biological sciences Ph.D. graduate from the University of Rhode Island, and his advisor, Associate Professor Carlos Prada, have published a paper in Nature Communications, revealing key mechanisms in speciation in corals and proposing a new hypothesis on the origin of species in the ocean. 

Their new study examines how coral species form and contributes to long-standing questions in evolutionary biology about how marine biodiversity originates. The work builds on decades of ecological, reproductive, and evolutionary studies led by national academy member Nancy Knowlton and pioneering researchers and co-authors Don Levitan and Mónica Medina — a legacy that Gómez-Corrales and Prada are continuing to develop.

A closer look at corals

One of the most iconic examples of mutualism is the relationship between reef-building corals and micro (dinoflagellate) algae. These symbionts harvest light and provide corals with more than 90% of their energy through photosynthesis. As a result, both corals and algae adjust their physiology and morphology to enhance performance across different light environments, such as those found along depth gradients.

While corals and their close relatives lack eyes, they are able to perceive light and do so using the same light-sensitive protein receptors (rhodopsin) on cones or rods in human eyes. 

Prada says their recent research revealed a new twist, uncovering the molecular mechanisms behind speciation in the ocean: “We discovered that opsin genes, the same genes responsible for vision in human eyes, play a key role in driving this process.”

The role of rhodopsin is well-established in fish adapted to different wavelengths across multiple species and geographic locales. For instance, a single amino acid substitution in an opsin gene in the Baltic herring has evolved more than 20 times independently in other species adapted to red-shifted light environments.

Traditionally, marine speciation has been attributed to rapid evolution of sperm-egg interaction proteins. This study presents a complementary view, showing that species can diverge through habitat-specific adaptation to light cues that regulate spawning, with rhodopsins mediating these cues and driving reproductive isolation in corals. This was the first time rhodopsin’s role in coral divergence was found.

Such a pattern of parallel divergence could occur independently in corals as they colonize waters with different optical properties, favoring rhodopsin divergence that fuels speciation.

This mechanism would allow corals to evolve reproductive isolation via genes involved in phototransduction signals that cue reproduction.

Speciation study

The Nature Communications study builds on earlier work by Prada, who proposed that speciation in corals occurs as a result of adaptation to live at different depths with different light environments (ecological speciation), a mechanism that has gained traction in the last two decades with examples ranging from plants to vertebrates. Unveiling the mechanisms behind reproduction isolation is central to understanding this process.

Gómez-Corrales and Prada investigated a recent divergence within a common Caribbean reef builder (Orbicella faveolata), where lineages diverged approximately 212,000 years ago across a narrow depth range in the water, less than 20 meters. The team showed that depth-related distributions are common among sister lineages of corals within the upper, sunlight-filled zone of the ocean. They focused on the Orbicella species, looking at the drivers of adaptive divergence and how corals display environmental sensing, studying coral colonies from Puerto Rico, Panama, Mexico, and Florida. Their analysis indicates divergence across depths through adaptation across different environments, highlighting avenues to increase biodiversity in the sea.

Coral’s reproductive processes are triggered by the interaction of differential light wavelengths, such as moonlight, neuropeptides (including dopamine), and temperature variation, which excite light receptors on the coral. By comparing genomes of deep and shallow lineages, Gómez-Corrales’ team demonstrated that the genes associated with environmental sensing in corals evolve under strong natural selection.

Genome differentiation between shallow and deep lineages occurs primarily in proteins responding to environmental sensing, affecting signaling pathways linked to coral reproductive cycles. This pattern is echoed at macroevolutionary scales across other aquatic species, such as jellyfish and sea anemones, in which neuropeptides, light, and temperature variations regulate reproductive physiology.

Notably, they found that corals use the same environmental cues tied to natural cycles to time reproduction. Coral species alter their reproductive timing under light and temperature manipulation experiments, hinting at a common mechanism for fine-tuning reproductive activity via environmental sensing.

Given the significant body of evidence supporting light as the primary sensory cue for coral spawning, Gómez-Corrales and Prada propose that differential timing of spawning driven by different light perceptions across depths is fine-tuned by expression changes in rhodopsin-like genes, causing corals exposed to different light environments to perceive spawning cues differently due to light. This process occurs across the coral tree of life and in all ocean basins across the world.

Understanding this research fills a key gap in understanding how reef species form, showing how speciation, light interactions, and ecology shape ocean biodiversity and inform predictions of marine ecosystems under climate change.

Prada says studies such as this highlight why it’s so important to better understand coral responses to ocean warming and ways that coral can adapt and acclimate to their environments, to highlight challenges and opportunities for conservation and restoration effort in the future.

“My passion for studying speciation stems from the gap between the vast biodiversity on coral reefs and our poor understanding of the mechanisms that generate and maintain this diversity,” adds Gómez-Corrales. “Uncovering the evolutionary processes shaping their diversification gives us important tools to help preserve them in the future.”

In addition to support from URI and the College of the Environment and Life Sciences, this project was supported by the International Coral Reef Society, the American Museum of Natural History, the National Science Foundation, the National Oceanic and Atmospheric Administration, and the Global Marine Initiative Student Research Award Program (The Nature Conservancy and URI).

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Journal

Nature Communications

DOI

10.1038/s41467-025-65226-9 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Speciation across depth gradients in reef corals