GEO Satellite Communication Systems Research Articles

PS-G-GERT effectiveness evaluation model of link-based GEO satellite communication constellation under poor information background

The effectiveness evaluation of GEO satellite communication constellation not only characterizes the communication capability of the constellation but also provides a basis for optimizing the constellation structure. Whether due to information poverty or the complexity of the system, the impact of uncertain information on the effectiveness evaluation needs to be considered to ensure the accuracy of the evaluation results. To address this issue, this paper develops a model for evaluating the GEO satellite communication constellation's effectiveness in the context of poor information. Firstly, it analyses the GEO satellite communication constellation plus system based on communication links with an in-depth analysis of the constellation structure. Secondly, an equivalent transfer function algorithm based on the characteristic function and transfer probability is proposed with the help of graphical evaluation and review technique. Then, by analyzing the communication link importance connotation, the algorithm formula of communication link effectiveness and its importance is derived, and the constellation effectiveness and variance are found. Finally, the model constructed in this paper is used to evaluate the effectiveness of a GEO satellite communication constellation, further verifying the accuracy and validity of the model. Through comparative analysis, it is shown that the model can not only solving the effectiveness of the constellation but also analyzing the variation of its effectiveness. It lays a theoretical foundation for the analysis and optimization of the GEO satellite communication constellation effectiveness.

Capacity pre-allocation based on a traffic prediction for latency reduction in geo satellite communication systems

Low latency is an important indicator for satellite communication systems on geo earth orbits (GEO). Transmission delay in packet networks includes access delay, propagation delay, and processing delay. The processing delay depends on the performance of the processing methods and system overload management, which is just a small fraction of the total transmission delay at low traffic load. This article dis-cusses the latency of a terminal accessing a network after a connection break. The paper proposes the scheme for maintenance a user terminal synchronization in a satellite communication net-work with bandwidth pre-assignment. The scheme is based on a traffic prediction and not requires a request from the terminal. The place of the proposed scheme in the synchronization maintenance system of the DVB-RCS2 standard is defined. A comparison of the performance of predictive traffic models is given. The latency reduction and the signal-to-noise ratio operating range extension of a user terminal from the use of the proposed scheme for maintaining synchronization is presented. The paper also presents an overview of the application of data analysis methods in the tasks of the time-frequency resource allocation in a GEO satellite communication system.

Flexible Resource Optimization for GEO Multibeam Satellite Communication System

Conventional GEO satellite communication systems rely on a multibeam foot-print with a uniform resource allocation to provide connectivity to users. However, applying uniform resource allocation is inefficient in presence of non-uniform demand distribution. To overcome this limitation, the next generation of broadband GEO satellite systems will enable flexibility in terms of power and bandwidth assignment, enabling on-demand resource allocation. In this paper, we propose a novel satellite resource assignment design whose goal is to satisfy the beam traffic demand by making use of the minimum transmit power and utilized bandwidth. The motivation behind the proposed design is to maximize the satellite spectrum utilization by pushing the spectrum reuse to affordable limits in terms of tolerable interference. The proposed problem formulation results in a non-convex optimization structure, for which we propose an efficient tractable solution. We validate the proposed method with extensive numerical results, which demonstrate the efficiency of the proposed approach with respect to benchmark schemes.

Connectivity services based on optical ground-to-space links

Repeater systems in a geostationary orbit utilizing free-space optical-communication offer great potential to backup, process and archive large amounts of data collected or generated at remote locations. In contrast to existing or upcoming global satellite communication systems, such optical GEO relays are able to provide a huge return-channel data throughput with channel rates in the gigabit-per-second range. One of the most critical aspects of such data uplinks are atmospheric disturbances above the optical ground terminals used to connect to the space segment. In this study, we analyse the design drivers of optical ground stations for land-based applications. In particular, the effects of atmospheric attenuation and atmospheric turbulence are investigated. Moreover, we present implementation ideas of the necessary ground infrastructure and exemplify our results in a case study on the applicability of free-space optical satellite communication to the radio astronomy community. Our survey underpins pre-existing ventures to foster optical relay services like the Space-Data-Highway operating via the European Data Relay System. With well-designed, self-sufficient and small-sized ground terminals new user groups could be attracted, by offering alternatives to the emerging LEO mega-constellations and GEO-satellite communication systems, which operate at low return channel data rates across-the-board.

Forced-Retransmission Based Hybrid HARQ Scheme for GEO Satellite Communications

In this paper, a hybrid HARQ scheme was proposed by combing forced retransmission and traditional HARQ together, after analyzing the characteristics of satellite channel and the problem encountered when utilizing HARQ scheme in GEO satellite communication system. The forced retransmission can make a packet be correctly decoded more quickly and shorten the waiting delay. Meanwhile, to balance the delay and throughput, the proper parameters were given for the proposed hybrid scheme. Simulation results show that the proposed scheme performs well at decreasing the waiting delay, especially when SNR is low. The conclusion can be drawn that the proposed scheme can improve the HARQ performance in GEO satellite communication systems.

Interference Modeling and Analysis for Inclined Projective Multiple Beams of GEO Satellite Communication Systems

In multi-beam satellite systems, Inter-Beam Interference (IBI) has a great effect on system performance. Within range of satellite coverage area, inclined projective multiple beams give rise to elliptic beam projections, resulting in that the distribution of beam projections is different from traditional cellular distribution. In this paper, an Inclined Projection (IP) model is proposed for IBI in OFDMA based GEO satellite communication systems, and corresponding analysis is also included. A comparison of carrier to interference power ratio (C/I) of users at the center of each cell with and without the consideration of IP is made, based on the simulation using different Frequency Reuse (FR) factor. The corresponding conclusions are presented. This research can provide reference for later satellite beam planning.