CubeSat Communications: Recent Advances and Future Challenges (1908.09501v2)

Abstract: Given the increasing number of space-related applications, research in the emerging space industry is becoming more and more attractive. One compelling area of current space research is the design of miniaturized satellites, known as CubeSats, which are enticing because of their numerous applications and low design-and-deployment cost. The new paradigm of connected space through CubeSats makes possible a wide range of applications, such as Earth remote sensing, space exploration, and rural connectivity. CubeSats further provide a complementary connectivity solution to the pervasive Internet of Things (IoT) networks, leading to a globally connected cyber-physical system. This paper presents a holistic overview of various aspects of CubeSat missions and provides a thorough review of the topic from both academic and industrial perspectives. We further present recent advances in the area of CubeSat communications, with an emphasis on constellation-and-coverage issues, channel modeling, modulation and coding, and networking. Finally, we identify several future research directions for CubeSat communications, including Internet of space things, low-power long-range networks, and machine learning for CubeSat resource allocation.

• The paper reviews recent technological advances and future challenges in CubeSat communications, analyzing key areas like constellation design, channel modeling, and networking.
• It details critical technical aspects, including the adaptation of channel models for dynamic orbital environments and analysis of link budget factors impacting communication reliability.
• The study highlights advancements in networking protocols, cooperative techniques, and future directions towards integrating CubeSats into IoST and 5G ecosystems.

CubeSat Communications: Recent Advances and Future Challenges

The paper "CubeSat Communications: Recent Advances and Future Challenges" provides a thorough analysis and review of CubeSat missions, complemented by an exploration of the technological advancements and the foreseeable challenges within this domain. The paper is an essential contribution to the body of knowledge, serving as both a primer and a roadmap for future developments in CubeSat communication systems.

CubeSats, or miniaturized satellites, have gained significant traction due to their cost-effectiveness and diverse applications in space-related research and services. These applications range from Earth observation and space exploration to extending global connectivity, making CubeSats a pivotal framework for integrating with pervasive IoT networks, which the paper terms as evolving towards an Internet of Space Things (IoST).

Key Aspects and Technological Advances:

The paper explores various aspects of CubeSat missions from both academic and industrial perspectives. Central to its analysis is CubeSat communications, particularly the issues surrounding constellation design, channel modeling, and system networking.

1. Constellation Design and Coverage: The design of CubeSat constellations heavily influences mission coverage, influencing decisions on the number of satellites, orbital planes, altitude, and inclination. The paper discusses several constellation designs, such as Walker constellations, street-of-coverage constellations, and Flower constellations. Each design type has application-dependent advantages and limitations regarding global coverage. CubeSat swarms as a concept are also explored, shedding light on future networks of interconnected small satellites to enhance coverage and mission flexibility.
2. Channel Modeling: The paper emphasizes the importance of developing accurate channel models tailored for CubeSat communications. For CubeSat-to-ground and inter-satellite communications, channel models originally developed for Land Mobile Satellite (LMS) systems are reviewed. These include statistical models like Loo's, Patzold's, and Hwang's models, adapted to compensate for unique challenges such as Doppler shifts, shadowing, and multipath fading, which affect the link performance and reliability in dynamic orbital environments.
3. Link Budget: The link budget is a critical component in ensuring reliable CubeSat-ground communications. The paper provides a detailed examination of the factors affecting the link budget, such as free-space path loss, atmospheric losses, and antenna gains. The analysis quantifies the impacts of elevation angle and altitude on communication performance, offering valuable insights into the trade-offs required for effective deployment.
4. Modulation and Coding: The paper reviews various modulation and coding schemes, highlighting those most suitable for different frequency bands and communication requirements in CubeSat missions. It underscores the need for power-efficient and robust schemes like GMSK and OQPSK, especially given the limited power resources on CubeSats. Attention is also given to the role of adaptive modulation schemes in mitigating propagation variability and maintaining a balance between bandwidth efficiency and power constraints.
5. Networking and Future Directions: Networking protocols for CubeSats are crucial for ensuring efficient communication routes, leveraging cooperative communication techniques to optimize power and data transmission. The paper also foresees an integrated role for CubeSats in future wireless networks, suggesting research directions in resource allocation and the significant potential of Software-Defined Networking (SDN) and Machine Learning for dynamic resource management.

Overall, the paper serves as an insightful recapitulation of the current state of CubeSat communications while proposing practical and theoretical extensions crucial for the future realization of IoST ecosystems. Future research directions highlighted include the integration with existing wireless network infrastructures such as 5G, advanced data scheduling techniques, multi-band communication strategies, and machine-learning applications for dynamic resource allocation. These directions underline the evolving landscape of global connectivity, emphasizing the growing role of CubeSats as enablers for a robust, interconnected future.