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This paper proposes a MAC protocol based on distributed micronano satellite network. Analyze the established mathematical model and get the influence of system parameters on network performance. This paper presents an improved protocol which adapts to distributed satellite network composed of nanosatellites. The protocol is compatible with inter-satellite communication and inter-satellite ranging functions. The research has resulted in a solution of MAC protocol for distributed satellite network.

In MEO-LEO satellite network, a MEO can establish connections with multiple LEOs at the same time. In order to maximize the use of satellite network resources, traffic allocation between MEO and LEOs is very important. This paper first describes the two-layer satellite network system model and point out the importance of traffic allocation among multiple LEO to MEO. Then, by quantifying the traffic resources that can be received by MEO and traffic requirements from multiple LEOs to MEO, and taking into account the remaining visible of MEO to LEOs, a traffic allocation strategy based on Q-learning in two-layer satellite networks was proposed, which aims to maximize the utility of LEOs to MEO in a given time. Then the paper grades the LEO traffic requirements to reduce the computational and storage complexity of the system. Finally, the effectiveness of the proposed strategy is verified by simulation.

In the low earth orbit satellite network, since the running speed of low earth orbit satellites is much higher than the average speed of mobile users, users frequently switch. It is necessary to solve the problem of how to find the best switching satellite and how to effectively use the limited channels, so as to improve the service quality of users. In this paper, the current situation of switching strategies in satellite networks is analyzed, and the applicability of existing beam switching strategies and inter-satellite switching strategies for channel allocation and how to find the best switching target satellite in satellite-ground integrated networks is explored. The development and challenges of switching strategies in LEO satellite networks are also analyzed.

Satellite connections are critical for continuous network connectivity when disasters strike and for remote hosts that cannot use traditional network connections. While satellite Internet bitrates have increased, satellite latencies can still degrade TCP performance. Assessment of TCP over satellite networks is lacking, typically done only by simulation or emulation only, if at all. This paper presents experiments over a commercial satellite network comparing two popular TCP congestion control algorithms: Cubic (the default for most Internet servers) and BBR (recently deployed by Google servers). Analysis of the results shows similar steady-state bitrates for both BBR and Cubic, but with BBR having significantly higher bitrates (and, subsequently, higher round-trip times) than Cubic during start-up.

Aiming at the problem that the ant colony algorithm converges slowly and easily falls into the local optimal solution under the complicated satellite network environment, a multi-objective optimization routing algorithm of satellite network based on ant colony algorithm is proposed in this paper. In the algorithm, the bandwidth is used as direction guiding factor when initializing the pheromone, which reduces inferior solutions and speeds up the convergence speed of the algorithm, when designing the heuristic function, the time delay, duration, and residual energy of node are considered to calculate the actual effective distance instead of the link length of traditional ant colony algorithm, prompting the ants to search in the target direction. What’s more, the wolf allocation strategy making good use of the better solution and the poor solution is adopted to update the pheromone in this algorithm. It improves the global search ability. The results of a large number of simulation experiments show that our proposed algorithm which satisfies a variety of on-satellite constraints can obtain improvement of the convergence speed and search ability compared with the traditional ACO algorithm and the MSNRM-DA algorithm.

To improve the convergence speed of routing and wavelength assignment (RWA) algorithm of satellite network, the Fast Convergence RWA based on Ant Colony Algorithm (ACO-FC RWA) is proposed. The results show the better network performance.

Low Earth Orbit (LEO) satellite network is experiencing renewed interest due to its potential to revolutionize wide-area communications. However, it may suffer different failure modes than many traditional networks given its location in the complex space environment. In this paper, we address this problem by focusing on the survivability of LEO satellite network under link failures. Specifically, we investigate two kinds of guaranteed based approaches to solve this problem and combine them in a uniform framework using optimization method, e.g., linear programming: 1) protects against any combination of up to k concurrent link failures, for a configurable value k; 2) enables guarantees such as "user i is guaranteed b i network bandwidth at least β% of the time". Simulation on up-to-date mega-constellation show that our proposed framework can protect delay-sensitive traffic from suffering long delay or data loss. In addition, they can support more traffic demands for the specified level of availability (e.g., 90%) under link failures.

This paper provides a new perspective for IP mobility support in LEO satellite network, that the network mobility should be solved via network driving rather than terminal driving methods. Terminal driving methods comes from terrestrial network which ones are typically reactive to the moving of users and improve the predictability of the terminals’ motion behaviors to enhance the performance. However, the mobility in LEO satellite network most comes from network(satellites) rather than terminals. It is inefficient to solve the continuous, high-speed, global and regular network mobility via terminal driving solutions who are designed for intermittent, low-speed, local and irregular user mobility. After modeling the satellite mobility behavior for single and multiple orbit plane, a network driving mobility management solution, namely NDM, is proposed in this paper, including 1) trigger and selection 2) proxy group handover 3) silent and explicit resource release. NDM utilizes the benefit of network driving and cooperate with terminal driving methods for robust consideration. Evaluations are conducted to proof the feasibility of mechanism to improve performance and apportion cost.

Due to the network topology high dynamic changes, the number of ground users and the impact of uneven traffic, the load difference between SDN-based satellite network controllers varies widely, which will cause network performance such as network delay and throughput to drop dramatically. Aiming at the above problems, a multi-controller optimized deployment strategy of satellite network based on SDN was proposed. First, the controller's load state is divided into four types: overload state, high load state, normal state, and idle state; second, when a controller in the network is idle, the switch under its jurisdiction is migrated to the adjacent low load controller and turn off the controller to reduce waste of resources. When the controller is in a high-load state and an overload state, consider both the controller and the switch, and migrate the high-load switch to the adjacent low-load controller. Balance the load between controllers, improve network performance, and improve network performance and network security. Simulation results show that the method has an average throughput improvement of 2.7% and a delay reduction of 3.1% compared with MCDALB and SDCLB methods.

This paper details the architecture and employment of a link-layer user-uplink simulator and a methodology that enables prediction of the spectrum demand of various connection service mixtures through the use of random forest machine learning. The results show that a model can be produced using this methodology. Predictions are used as an input to a channel load balancing algorithm, with the goal of learning the behaviour of the scheduling and framing algorithms.

For multipath transmission, the congestion control based on shared bottleneck detection not only improves the throughput in the Non-Shared Bottlenecks(NSB) scenario, but also maintains fairness to other connections in Shared Bottlenecks(SB) scenario. However, due to sharp difference of post-paths' delay(DPPD) in high latency satellite networks, most of existing shared bottleneck detection schemas misused irrelevant data result in poor performance. In this paper, the relationships of OWD s between two subflows are analyzed firstly. Then, we propose a robust schema based on difference estimation of post-paths' delay(DEPPD) to detect shared bottleneck for multipath transmission in high latency satellite networks. Our schema searches for a continuously matching sequence among the elements of two congestion event arrays, and uses the mean intervals of matched congestion events as estimate of DPPD to judge whether the next pair congestion events match. If the tail element of one array can be matched in some way, there is a shared bottleneck between the two subflows. Otherwise there is no shared bottleneck. The schema is implemented in multipath quic(MPQUIC) and simulations demonstrate that DEPPD can achieve higher accuracy in our scenario and remain stable with variations of DPPD, comparing to other techniques.

This Satellite network has many disadvantages such as long round-trip-time (RTT), high bit error rate. The issues above pose challenge to existing Slow start algorithm. Slow start algorithm is a key component which directly affects startup performance of TCP. This paper mainly improves startup performance of TCP and proposes a slow start algorithm that adopts logarithmic function to overcome multiple congestion packet loss caused by inaccurate ssthresh (slow start threshold) estimation and improves throughput performance.

This paper proposes an SDN-enabled integrated space- ground network simulation platform. It could adapt a dynamic satellite network topology from the output of satellite simulation tool, employ customized routing algorithm to establish end-to-end communication path dynamically.

In order to solve the problem of load imbalance caused by the changing topology and real-time changes of service requests in SDN/NFV cooperative deployment satellite networks, the load balancing optimization algorithm based on Viterbi algorithm for minimum migration cost (MLB-Viterbi) is proposed. This method establishes the mapping process of SFC as a hidden Markov model. Considering the migration cost and the constraints in migration, the MLB-Viterbi algorithm is used to migrate the VNF resources of the overloaded nodes to other suitable nodes and adds a migration cost function to the state transition matrix, so as to multi-objective optimization. The results show that MLB-Viterbi algorithm has better convergence than MRLB algorithm in load balancing performance. With the increase of the number of reconstructed service chains, MLB-Viterbi algorithm has more advantages than multi-steps in the cost of migration. The cost of updating the service chain depends on the number of service chains in a linear way.The algorithm can effectively achieve load balancing and ensures the minimum migration cost.

This paper presents a new design approach for vehicular accidents management using telematics systems. The proposed system considers the use of a microprocessor to estimate the severity of the vehicular accident, the joint use of satellite services and terrestrial mobile communications systems and the use of a computer program that allows to determine the exact location of the accident and the nearest emergency services. The obtained experimental results allows to show the performance of the proposed design.

The article highlights the analyses of GSO orbit occupancy with respect to the notified GSO satellite systems, the main contemporary development trends of satellite communication systems, such as the use of earth stations in motion and the earth stations communicated with FSS satellite networks or systems on the GSO and non-GSO orbits. Some items on the perspective V-band use are also considered here.

Satellite communication has limited bandwidth resources and many types of carrying services. How to carry high-quality emergency voice services in limited bandwidth has become a problem.Using voice compression technology and network traffic engineering can efficiently use satellite network bandwidth resources on the basis of meeting users'voice quality requirements, and provide users with differentiated high-quality services

Aiming at the problems of lack of simulation training means, low fidelity of simulation training and weak real-time control of network simulation in satellite communication system, the idea of constructing simulation training system of satellite communication based on HLA, VR and OPNET is put forward, the key technologies needed for the realization of the system are analyzed and studied, the architecture of simulation training system of satellite communication based on HLA is designed, and the OPNET is also discussed. The functions, functions and Implementation Paths of the main federates such as satellite network simulation federation and virtual satellite station are designed.

Due to the relative orbiting of IGSO satellites and MEO satellites in IGSO/MEO double-layered satellite network, the inter-layer links of the IGSO/MEO double-layered satellite network need to be dynamically switched, resulting in dynamic changes of the satellite network topology. Traditional interlayer link establishment strategies are generally low -orbit-centric and assume that the number of inter-layer links equipped on high-orbit satellites is not limited. Moreover, the beam coverage constraints are often not considered. Therefore, traditional inter-layer link establishment strategies are hard to apply in practice. In this paper, the conditions for establishing the inter-layer links are first formulated for the IGSO/MEO double-layer satellite network with the consideration of beam coverage. Then, an inter-layer link establishment strategy which is high-orbit-centric is proposed where we assume that the high-orbit satellite has only one inter-layer link and uses this as a premise to establish the inter-layer links. Finally, the inter-layer link establishment strategy is simulated and analyzed, and the inter-layer link establishment strategy which is high-orbit-centric is visualized.

The dynamic topology of integrated terrestrial-satellite networks and limited resources in space segment bring challenges to the design of efficient routing and traffic engineering (TE) schemes. In this paper, we proposed a segment routing based routing/TE framework for integrated terrestrial-satellite networks. In particular, we showed that near-optimal performance can be obtained with a limited number of middle nodes placed in the segments compared to multi-commodity flow. Furthermore, we formulated the segment routing problem with maximum profit as a primal-dual set cover problem, and presented an online heuristic algorithm to solve the optimization problem. We have proven that the proposed algorithm is $\left[ {\frac{1}{2},\log d} \right]$-competitive. Simulation results show that the proposed algorithm outperforms the traditional satellite algorithms in terms of throughput and rejection probability. In addition, we presented an implementation architecture of the segment routing in integrated terrestrial-satellite networks.

Satellite communication is considered as an indispensable method in the future seamless wireless networks. In this paper, we first propose an opportunistic user scheduling scheme for a dual-hop satellite relaying with decode-and-forward (DF) protocol. Then, by supposing that the satellite links experience Shadowed-Rician (SR) fading, we derive the closed-form outage probability (OP) expression for the considered system. Finally, computer simulation results are given to demonstrate the validity of the performance analysis and verify that the OP of the dual-hop satellite relaying system can be improved through multi-user diversity. Our work is helpful for the engineers to design a practical satellite network.

Aiming at the problem of preferential competition of information caused by the fusion of terminal nodes and routing nodes in navigation satellite network, a terminal-prioritized network node transmission model is proposed. The characteristics of topology, routing, and service information path of the navigation satellite network was analyzed, and the terminal-first network node routing model and the mixed-preferred network node routing model was designed. Simulations based on the packet delivery delay and network throughput index show that the terminal-first network node routing model can achieve higher transmission performance.

In this paper, a Low Earth Orbit (LEO) satellite network capacity model is proposed to value the influence of topology and routing strategy on throughput capacity. Under the network capacity balance framework, two topology strategies and two routing algorithms are studied. The analysis solution shows that for LEO constellation, the topology strategy with opposite direction links could increase the quantity of inter satellite link (ISL), reducing the traffic on each link. Central routing algorithm presents superior traffic distribution ability in LEO network than distributed routing strategy. Simulation results prove that central routing algorithm combined with opposite direction ISL topology in LEO satellite network could reduce data packet loss rate, achieve optimization and robustness on network capacity.

With the evolution towards 5G networks, the current system architectures gain more interoperability that allow services to perform at increased efficiency. In the case of telco networks, by integrating a satellite backhaul, a wider range of services can be obtained for the end devices, while at the same time optimizing the backhaul usage. In this paper we present a set of evaluations performed on virtual evolved packet core network with GEO satellite network is used as backhaul. The proposed system is deployed in 2 configurations on which various telco functionalities are tested in order to determine which range or applications are suited for each setup. The testbed includes the Fraunhofer CoSat satellite emulator and the Open5GCore toolkit, and was used for functional tests as well as performance benchmarks.

BeiDou Navigation Satellite System (short for BDS) officially provided service to most parts of Asia since December 27th. 2012[1]. After a year of testing and evaluation work China Satellite Navigation Office published “BeiDou Navigation Satellite System Open Service Performance Standard (Version 1.0)” (hereinafter short for “BDS-OS-PS-1.0”) in December 2013[2], which presented each performance index of BDS service. Among 2016 China launched two satellites of IGSO-6 (NO.22, March 30th) and GEO-7 (NO.23, June 12th), and before the formal operation services both of them still needed further testing and evaluation work of satellites network, which obtained the actual testing results of every performance index to provide the basis for network operation and service performance commitment. Therefor taking “BDS-OS-PS-1.0” as the basis we undertook the timing evaluation work of each satellite network, which analyzed the satellites timing performance in B1, B3, B1/B2, B1/B3 frequency bands as well as the contribution to the current system. The results showed the timing performance of IGSO-6 and GEO-7 could meet the requirement of timing precision better than 50ns, and either of them adding to BDS would improve the precision and reliability of system service.

Enhancing mobility in a highly dynamic LEO satellite network is a critical issue to achieve seamless and efficient interconnection of satellite network and terrestrial mobile endpoints. Virtual attachment point approach is investigated to hide the mobility of satellites from the mobile endpoints. In this work, mathematical models for both earth-fixed footprints and satellite-fixed footprint are introduced along with their contributions to the virtual attachment point availability. Comparing the evaluation results, we conclude with the benefits of constructing an earth-fixed footprint based virtual attachment point.

This paper addresses the evolution of microwave and RF technologies for communications satellite payloads that have contributed to the deployment of flexible payload architectures resulting in efficient use of critical satellite power and bandwidth resources. These technologies have made relatively complex space based systems feasible thus offering fixed and mobile satellite services, and have also resulted in satellite payload size/weight reductions, reliability enhancements, and significant performance improvements. Innovations in active and passive RF subsystems, including on-board microwave switches, signal channelization and routing technology, narrow spot beam operation with re-configurability, have resulted in satellite network operational flexibility, frequency reuse, capacity enhancements, and use of smaller and lower cost terminals.

With regarding to the unbalanced load and the multimedia service of multimedia QoS requirements in GEO/LEO double layer satellite networks, a GEO/LEO double layer satellite networks multi-service routing algorithm is proposed. Based on satellite network topology dynamic discretization, the algorithm defined link initial weights with delay and residual bandwidth and introduced the concept of key link. Combining business utilization to adjust different business link initial weights, so as to allocate network resources reasonable, content a variety of QoS requirements and optimize the satellite network link utilization. The simulation results show that the algorithm not only guarantees the delay requirements of different priority business, but also upgrade the properties of throughput and load balancing relatively, improve the performance of satellite network system as a whole.

According to the actual need of fault location of satellite communication system, a fault synthetic diagnosis method based on C4.5 algorithm and expert knowledge database is proposed. The basic principle of C4.5 algorithm and expert knowledge database is discoursed. The process of building C4.5 fault diagnosis model and expert knowledge database is focused on and the implementation procedure of diagnosis process is described in detail.