International Journal of Satellite Communications and Networking最新文献

The new era of satellite communications will rely on thousands of highly flexible spacecraft capable of autonomously managing constellation resources, such as power or frequency. Previous work has focused on the automation of the individual tasks that compose the resource allocation problem (RAP). However, two aspects remain unaddressed: (1) A unified method that autonomously solves the RAP under nongeosynchronous conditions is still to be developed, and (2) the cost–benefit of using optimization methods remains to be studied. Note that these studies are critical for satellite operators to take appropriate decisions concerning the automation of communications constellations operations. To close this gap, this work proposes an adaptive framework to solve the RAP for high-dimensional nongeosynchronous satellite constellations. The proposed framework uses a divide-and-conquer approach that solves each step of the RAP, leveraging different optimization algorithms at the subproblem level to produce a valid and efficient allocation of resources over long time horizons. When comparing the proposed method against scalable greedy solutions, the former achieves up to four times more constellation capacity and reduces the overall consumed power by up to a factor of 3. The cost–benefit analysis reveals which RAP subproblems should be prioritized depending on the operator's objectives. Studying diverse operational conditions, we find that optimization methods enhance capacity consistently yet might raise power consumption due to trade-offs in the routing algorithms.

This paper presents a comprehensive survey of advancements in resource allocation techniques within the realm of multibeam satellites, focusing specifically on four key areas related to payload beam hopping, along with allocations of power, bandwidth, and beamwidth. It provides a comprehensive examination of traditional approaches alongside the innovative adoption of artificial intelligence and machine learning (AI/ML) methods to tackle these obstacles. A comprehensive analysis is carried out to investigate the possible approaches to enhance the resource allocation efficiency further. While acknowledging the plethora of topics within the multibeam satellite domain, this study deliberately narrows its focus to these four fundamental aspects, providing a nuanced understanding of the evolving landscape in satellite communications.

As global informationization deepens, the importance of Space-Ground Integrated Network (SGIN) as a new network architecture becomes increasingly prominent. SGIN combines the advantages of ground and space networks, enabling global information interconnection and sharing through various communication means such as satellites, drones, and ground stations. However, due to its complex network environment and diverse communication requirements, traditional network architectures struggle to meet its demands for efficiency, stability, and scalability. To address these challenges, we focus on the research, design, and implementation of a cloud-edge collaboration-based multi-cluster system for SGIN. The goal is to construct an efficient, stable, and scalable network system capable of providing seamless global coverage and efficient communication within SGIN. We design a multi-cluster system architecture based on container technology, leveraging cloud and edge computing techniques for dynamic resource allocation and efficient utilization. This architecture aims to meet the diverse network service requirements of ground terminals, enhancing responsiveness, efficiency, resilience, and reliability of network services. Additionally, we introduce a multipath data transmission mechanism to support the transfer of large-scale data, such as remote sensing images. A simulation platform tailored for SGIN is developed, demonstrating the feasibility of the multi-cluster system and the effectiveness of multipath data transmission.

It is becoming very common to use multiple GEO satellite inside the same longitude slot. There are different co-location strategies for that purpose but the most common one is to use “eccentricity and inclination separation” especially if the whole fleet is being controlled by the same operator. In this study, the determination of link availability by also considering the potential RF Interference between co-located satellites are examined. The main objective of the study is not to protect from the interference but to determine whether the satellites' orbital behavior may decrease the link availability and how much if they have potential of RF interference. In the study, two co-located GEO satellites are shown as a sample, but in principle, the philosophy demonstrated here can be used for three or more co-located GEO satellites.

Low earth orbit (LEO) satellites have the characteristics of low communication delay, low deployment cost, and wide coverage, which have become an important component of the 6G air-space-ground integrated information network. However, satellite-ground communication has a large propagation distance, complex fading, and fast terminal movement speed, causing the channel characteristics different from terrestrial communication networks. Therefore, channel modeling is necessary when deploying a satellite-ground communication network. In this paper, a 3D geometry-based stochastic model (GBSM) is proposed for satellite-ground communication links. The proposed channel model includes several environments such as urban, suburban, and rural. Based on this model, the channel impulse response (CIR) can be obtained, and the closed-form expression of spatial-temporal correlation function and Doppler power spectrum density are derived. Through simulation, the characteristics of large-scale fading and small-scale fading are analyzed, which depict the significant differences from the terrestrial networks. The relevant results can provide contributions to the design of future satellite-ground communication systems.

The paper analyzes the error performance of a basic satellite-terrestrial communication system, which uses a satellite as a source and receiver at the earth station as a destination. The system model accounts for an independent channel of fading and applies the theory of non-orthogonal multiple access (NOMA) to provide fair resource sharing and better connectivity among multiple users. The paper investigates the transmission characteristics and derives the expressions for the total symbol error rate (SER) of the proposed system model. Furthermore, it examines the transmission efficiency with the help of the elevation angle between the source and the destination. The paper also explores the impact of different fading environments on SER.