Space Information Networks

In this paper, based-on the GEO/IGSO satellite, we design a constellation to achieve global coverage. And the optimization for the coverage performance and inter-satellite link performance is provided. In order to maintain connection with ground station, two methods is proposed. The simulations and analysis for the constellation are given. The constellation can achieve the requirement of coverage and communication.

SDN paradigm has successfully manage to pave the way toward next-generation networking, but the research on SDN-based integrated satellite and terrestrial network has just started. SDN-enabled management and deployment architecture of integrated satellite-terrestrial network eases the complexity of management of infrastructures and networks, improves the maintaining and deployment costs, achieves efficient resource allocation and improves network performance of overall system. In this paper, we started introducing the SDN-based integrated satellite-terrestrial network architecture and discuss the unified and simple system functional architecture. Then we illustrate the two fundamental aspects of integrated network application functions. Following the demonstration of recent research works, we identify three challenges and discuss the emerging topics requiring further research.

The development of spacecraft electrical system in China has been reviewed. The electronic system has been divided into three generations of stand-alone system, federated electronic system and integrated electronic system. Then, the electrical architectures and features of the federated electronic system and the integrated electronic system have been analyzed. Finally, the development trend of spacecraft electronic system has been discussed.

Setup time between missions in the tracking and data relay satellite system (TDRSS) was treated to be time-invariant in most previous work on the system’s scheduling problem. This paper considers this problem based on dynamic setup time that is both sequence-dependent and time-dependent. Firstly, considering the actual daily operation property of the TDRSS, the original scheduling problem is transformed into the pointing route problem of inter-satellite link antennas. Then, by defining dynamic setup time and introducing new time-space constraints into the conventional scheduling model, we construct one mixed integer programming model with heterogeneous antennas. To solve this model, one algorithm based on reactive greedy randomized adaptive search procedures (Reactive GRASP) is implemented. The validity of the model and the algorithm procedure is verified through numerical simulations under different problem scales and multi-type data sets. Results show that compared with the conventional method, the scheduling success rate increases associated with an evident decline in the invalid resource consumption rate of Single Address antennas, which effectively improve the TDRSS efficiency.

Reviews of foreign spatial information network system design and demonstration technology development are introduced on this paper. Spatial information network system model is carried out. Considering about the complex architecture and characteristics, System construction and validation methods, architecture and assessment criterion are researched and integrated supporting environment is designed. It supplied the procedure and validation methods about concept system, technologies and evaluation. Also, the demonstration of its application is supposed here.

Distributed reconfigurable satellite is a new kind of spacecraft system, which is based on a flexible platform of modularization and standardization. Based on the module data flow analysis of the spacecraft, this paper proposes a network component of Microwave-Laser integration architecture. Low speed control network with high speed load network of Microwave-Laser communication mode, no mesh network mode, to improve the flexibility of the network. Microwave-Laser integrated network component technology was developed, and carried out the related performance testing and experiment. The results showed that Microwave-Laser integrated network components can meet the demand of future networking between the module of spacecraft.

As Chinese interests expensing into the oceans, space and electromagnetic areas, single Space-based information systems had been difficult to meet the growing needs of information acquisition, processing and transmission. Building a National Defense Space Information Network by integrating and interweaving space-based systems, was an important and urgent task to construction of information infrastructure for National defense and army, and was also an important guarantee for national security. Firstly, the concept and the connotation of National Defense Space Information Network were analyzed, and then the concept, composition and construction points of network were clearly defined. Secondly, the development course and the research status of American military space-based information systems were introduced in detail, which provided useful reference for China construction of National Defense Space Information Network. Thirdly, the “should be” architecture of National Defense Space Information Network was revalidated, then the key problems of network were analyzed in five aspects including network topology, transmission technology, node processing, and operation-maintenance-management-control technology and security protection. At last, some research advisements were given for China’s national defense construction.

Entering to the 21st century, with the rapid development of information technology and the increasing expansion of mankind activity, The space information network (SIN) has become the key development field in the great powers around the world, the study of SIN shows an ascendant trend. Based on the analysis of the dynamic and developing trend of SIN at home and abroad, by studying the characteristics of SIN and its essential rules, and in the face of two kinds of developing tendency such as “Resilient and Decentralized Spatial Architecture” and “Integrated and Large-scale Spatial Architecture”, this thesis proposes a new SIN architecture called “Space Information Cloud (SIC)”, and has deeply studied the system structure of the public cloud in the space information cloud (SIC). In the end, the key technologies relevant to the space broadband backbone network were analyzed and discussed oriented to SIC. So as to provide reference about the development of SIN in China.

This paper proposes a routing scheme for low earth orbit (LEO) satellite networks, named congestion-based random-encountering routing (CTR) scheme. Firstly, forward agents migrate autonomously to explore paths from source to destination satellite, while back agents follow the path in the opposite direction. Meanwhile, data probability table of every satellite will be changed according to the condition of satellites which agents gather and estimate, eg. congestion, propagation and queuing delay between inter-satellite link (ISL). Finally, simulation is performed on a Courier-like constellation. Moreover, results show that the proposed scheme guarantees better quality of service (QoS), especially shorter end-to-end delay and lower packet loss ratio, for load balancing.

The random access (RA) procedure in LTE systems is essential for the machine-type communication (MTC) in space information networks (SIN). By using the RA procedure, the delays of different MTC terminals could be aligned to the reference timing such that signals of each other could arrive at the satellite simultaneously. To this end, an enhanced iterative parallel interference cancellation (EIPIC) algorithm is proposed in this paper. Analyses show that the inverse impact of multiple access interference and near-far effect always persists even though the codes are ideally orthogonal with each other. The proposed algorithm could parallelly detect each possible code, re-construct its frequency-domain signal and cancel its inverse impact for further detection. And an optimized weighting vector is further applied for the frequency-domain signal re-construction based on the analyses of the mean square error. Simulation results show that the proposed algorithm could significantly improve the RA performance compared to existing algorithms.

As broadband satellite communication (SAT-COM) systems develop rapidly, Onboard Switching (OBS) technologies with flexible connectivity has attracted much attention by academic researchers and industry. However, due to the threat by the space radiation effects and the firm constraints of payload processing and power resources, OBS technologies are facing to great challenges in terms of its reliability and scalability. In the past literatures, in order to improve the connectivity and reliability of the single-path Crossbar switch, the multi-path Clos network is widely investigated for preferable adoption in OBS. Nevertheless, due to the extensive use of centralized scheduling, the current Clos network with low scalability is not applicable for high-throughput OBS systems. In this paper, by analyzing progresses and trends of decades of related researches, the developing directions of OBS are provided and discussed, combining the switching architecture, the queuing strategy and the corresponding scheduling algorithms. By employing specific queuing structure to sup-port distributed scheduling in the Clos network and along with distributed, fault-tolerant scheduling algorithms, the requirements for high scalability and fault tolerance of the OBS systems can be efficiently guaranteed, which is expected to be a new trend of OBS researches.

In Delay/Disruption Tolerant Networks (DTNs), most previous works proposed to re-forward data and recalculate the route between the local node and one of its neighbors depending on the priority of message. However, some lower priority messages in a contact are replaced by the higher priority messages, which leads to the lower throughput and higher data loss rate. In this paper, we focus on the route selection process with the consideration of network coding in Low Earth Orbit (LEO) satellite DTN communications, and propose an improved Contact Graph Routing (CGR) scheme by introducing the Destination based Network Coding (DNC), namely DNC-CGR, to improve the network throughput and reduce the number of messages in the Inter-Satellite Links (ISLs). Simulation results show that the proposed DNC-CGR scheme can significantly improve network performance in comparison to the existing CGR schemes.

Reducing handover delay at the same time of maintaining high level of handover security is always a challenging issue, especially for secure handover in space information network where resources are limited and links are highly exposed and intermittent connected. To address this issue, this paper focuses on reducing handover authentication delay and adopts the secure context transfer method as a replace for handover authentication. To achieve this purpose, a trust holding based secure seamless handover scheme is proposed. In this scheme, a full trust holding mechanism based on finite state machine is firstly proposed to build a light-weighted trust system. Then a secure trust state context transfer method is given based on the full trust holding mechanism. Instead of handover authentication, if a mobile node is trusted by current AP, history trust state information is sent to target AP to verify MN’s identity. A pre-authentication method is introduced as a complement to cope with the situation where MN is not trusted by current AP. With these, a node can easily build a trust relationship with target APs while handover begins. Security proofs and performance analysis demonstrate the effectiveness and efficiency.

Satellite communication is an important part of communication networks. Since the energy and the spectral of satellite system are limited, the energy efficiency and the spectral efficiency become two key performance metrics. However, these two metrics always increase in an opposite way. Quasi-constant envelope OFDM technology can provide high data rate communication links and maintain the peak-to-average power ratio (PAPR) less than 3 dB. It provides a way to get balance between these two metrics and it is suitable for satellite communication system. As the phase modulation method is used in quasi-constant envelope OFDM technology, the energy efficiency and the spectral efficiency of the system are all related to the modulation index. Since a typical satellite communication system contains various types of services, the problem is how to choose the appropriate modulation index according to the demands and conditions of different users. In this paper, a system performance model is proposed and it considers the energy efficiency and the spectral efficiency as two factors. The modulation index selection strategy is to choose the appropriate modulation index to maximize the system performance. The relationship between these two factors and the modulation index are analyzed and the system performance curves are given through simulation.

A novel microstrip magnetic dipole antenna with wide beam-width is proposed in this paper. It is working as a cavity backed slot antenna. The half power beam-width (HPBW) is 150° in the E-plane, and 85° in the H-plane. Its low profile of 0.03 \( \lambda_{0} \) (\( \lambda_{0} \) is wavelength of operating center frequency) and compact size of 0.31 \( \lambda_{0} \) * 0.32 \( \lambda_{0} \) make it suitable for the space communication systems. Due to the good performance of the antenna element, two linear phased arrays have been constructed, E-plane and H-plane phased arrays. The main lobe can scan from −76° to 76° for the E-plane phased array, and from −65° to 65° for the H-plane phased array with about a 3 dB gain fluctuation. Moreover, a planar phased array has been constructed. The scanning range is from −55° to 55° in all azimuth planes.

The movable spot-beam antenna of satellite can adjust its pointing flexibly, so it can meet the on-demand coverage need for the ground area. On the other hand, the Ka band is more and more utilized in the satellite communication system with the increasing demand of multi-media data business from users. However, the Ka band is susceptible to rain attenuation. In this paper, a kind of movable spot-beam schedule algorithm for resisting rain attenuation in satellite networks (MSBSA-RRA) is proposed for the adverse effects of rain attenuation on the communication performance of Ka-band. MSBSA-RRA establishes the optimal model of spot-beam antenna scheduling by using the optimization theory. Two kinds of users are set up in this paper, which are special users and ordinary users. The priority for special users is higher and its service quality needs to be guaranteed underlying. The attenuation margin factor is introduced in the optimization model, so the spot-beam antenna can give priority to special users under rainfall conditions. The optimization model is solved by classifying the spot-beam scheduling problem as the maximum weight perfect matching problem of bipartite graph. The performance of MSBSA-RRA is simulated and analyzed in this paper. Simulation results show that MSBSA-RRA can effectively reduce the drop call rate in the rainfall condition. Meanwhile, the influence of the attenuation margin factor on the performance of special users and ordinary users is also analyzed in this paper. It can be seen from the simulation results that the value of attenuation has a very important influence on the performance of MSBSA-RRA.

To meet the growth of real-time and multimedia traffic, the next generation of satellite networks with a guarantee of quality of service (QoS) is indeed, urgent. In this paper, we support the multi-layered satellite network as the scenario, owing to dynamic topology and distinct classification of the generated traffics. We map the satellite network system into a tandem queuing model, which the purpose is devoted to use a mathematical tool for evaluating the performance bounds of per-flow end-to-end networks. For delay-sensitive traffics, we compare two different arrival models–Poisson process and self-similar process. Meanwhile, we apply traditional scheduling strategy to MEO nodes while considering link impairment between a pair of satellites. Finally, we analyze, in a numerically way, which parameters (and how they) influence the per-flow end-to-end performance bounds. Our analysis can be used as a reference to China’s future satellite topology and routing algorithms designed and, optimization given a network with performance requirements and constraints.

Due to the movement of the receiver, the time-variant transfer function of the radio channel of the high altitude platform (HAP) is a non-stationary process. A theoretical non-stationary three dimensional (3-D) multi-cylinder HAP multiple-input multiple-output (MIMO) channel model is proposed in this paper. The space-time correlation function of the proposed 3-D HAP-MIMO channel is proposed in this paper. In addition, we propose a corresponding simulation model. Numerical results show that the simulation model could fit to the proposed 3-D HAP-MIMO channel model very well. This paper also investigates the capacity of spatially and temporally correlated HAP-MIMO channel achieved with uniform linear arrays (ULAs).

Space information network (SIN) is not only the key element to contact everything all over the earth, but also the important part of the information highway in the future. Architecture design is the basement of the whole space information network, in order to insure the access of the existing various types of satellites, aircrafts and ground facilities, while taking into account the cost of satellite and system performance, we design a double layer LEO satellite based “BigMAC” space information network architecture in this paper, which is compatible to the various existing satellite systems. The simulation results shows that the architecture is feasible and can provide others some construction of ideas in the future.

In recent year, the transmission of spatial information present the characteristic of amount users, broad coverage area, multiple service, and convenient access, which make research focus for SIN (spatial information network) users in the area of intelligent TT&C (telemetry, tracking and command) and management. Based on the deep analysis of TDRSS (Tracking and Data Relay Satellite System) application modes, an assumption of TT&C and management for SIN based on the TDRS SMA (S-band Multiple Access) system is proposed. Analysis is mainly focused on the panoramic beam, system composition and user access, also the protocol architecture, communication workflow, and TDRS terminal are original designed. Compared to traditional operational mode, the proposed assumption could realize ubiquitous perception, random access, on-line management, and satellite-ground cooperation for users’ application. Relevant result could be referenced in the study of TT&C and management for SIN.

The space-terrestrial integrated network able to cope with the complex and varied tasks in future communications. However, there are some problems in unified management and cooperative scheduling. In this paper, based on the situation of satellite and terrestrial integrated network, combined with software defined network (SDN), network function virtualization (NFV), and mobile edge computing (MEC), we propose a new space-terrestrial integrated network architecture. SDN is used to implement centralized management and unified control. Distributed and unified virtualization platform was constructed based on the technology of NFV. The deployment of MEC over NFV platform helps to improve the user experience and network service quality. Finally, analyzed several typical scenarios such as supporting for multi virtual operators, improving the emergency response and coverage capabilities, optimizing service driven link and route under the proposed architecture.

Airborne information networks have drawn the attention of the research community in the recent years. This growing interest can largely be attributed to new civil and military applications. Currently Airborne information networks are inherently hardware-based and rely on closed and inflexible architectural design. This imposes significant challenges into adopting new communications and networking technologies. Software Defined Networking, recognized as the next-generation networking paradigm, relies on the highly flexible, programmable, and virtualizable network architecture to improve network resource utilization, simplify network management, and promote innovation and evolution. In this paper, the concept of Software Defined Networking technology is introduced first. The features for the airborne environment and research challenges to realize the next-generation airborne information networks are discussed. Furthermore, a software-defined architecture is proposed to facilitate the development of the next-generation airborne information networks. The function of network virtualization was added, the SDN airborne information network provide differentiated services for airborne applications through employing the network virtualization technology. Aiming at the characteristics of airborne information network environment, a series of key technologies are analyzed in detail.

This paper firstly analyzes the present situation and the demand of the current air traffic management surveillance, and then lead to the necessity of constructing the satellite system for space aeronautics air traffic management information collection. Combining with the needs of the current air traffic management surveillance, the design constraints about the satellite system for space aeronautics air traffic management information collection are analyzed. A Walker satellite constellation system constituted by 81 micro/nano satellites is therefore designed. Using STK numerical simulation tool, we can get the Earth which is covered by 100% and the maximum coverage gap time is not more than 40s. Finally, considering the capability of the satellite system for space aeronautics air traffic management information collection, the future application prospects of the system are discussed.

LEO satellite networks, represented by the successful Iridium System, are composed of multiple satellite nodes and inter-satellite links (ISL). Numerous routing algorithms have been designed to determine satisfying routes between data flow sources and destinations, within the constraints including delay, congestion control, and throughput and load balancing. This paper proposes a distributed network-state aware self-adaptive routing algorithm based on neighbor ISL status and node workload. Every satellite node is independently responsible for forwarding datagrams in its queue, with information about network status piggybacked in the transmitted datagrams. Such information helps understand and predict the network workload status on each direction of the outgoing links, and is used for nearly-optimal selection of datagram outbound links to achieve load balancing and multi-path routing. Experiments are conducted on ns-2 simulation platform with a designed LEO walker, to implement and evaluate the effectiveness and efficiency of the proposed algorithm. The results show a significant improvement of more than 50% on the network workload balancing, with a few more hops in the selected multiple routing paths compared with the traditional Dijkstras shortest path algorithm.