Performance Analysis Of Satellite Communication System In Fading Channel

Compared with terrestrial communication systems,satellite communication has the advantages of wide coverage and no terrain restrictions.It provides a good means for solving broadband wireless access for users in oceans,deserts and other remote areas,and has become the sixth-generation mobile A key technology of communication system.This article analyzes the performance of the satellite communication system for a number of typical application scenarios,reveals the impact of some key parameters on the performance of the satellite communication system,and provides a reference and basis for the actual system design.The main work of this paper is as follows: Focus on evaluating important performance indicators such as system outage performance under the agreement,and verify the correctness of performance analysis through Monte Carlo simulation.1.Analyzed the performance of the multi-source and multi-destination node satellite communication system under the threshold judgment amplify-and-forward(AF)protocol.First,consider the effects of on-board antenna gain and satellite link loss,establish a more realistic system model,and obtain the system end-to-end output signal-to-noise ratio expression.Secondly,assuming that the uplink adopts time division multiple access technology and the downlink adopts the opportunistic scheduling scheme,and considering that both the uplink and downlink channels of satellite communication obey the shadowed-Rician distribution,it is derived The closed expression of outage probability of the system is obtained,and the high-order outage probability expression of the system under the condition of high signal-to-noise ratio is further obtained.Finally,the computer simulation verified the correctness of the theoretical analysis,and analyzed the influence of the number of users and channel parameters on the performance of the multi-user satellite communication system.2.Analyzed the security performance of the satellite communication system under the Decode-andForward(DF)protocol.Aiming at the scenario where the satellite signal is eavesdropped by multiple illegal users,the physical layer security transmission based on zero-forcing beamforming is proposed.The strategy further derives the closed expression of the system's safe outage probability and ergodic safe rate under the condition that both the gateway-satellite and satelliteuser links obey the shadowed-Rician distribution and the interference link obeys the Nakagamim distribution.Finally,computer simulations verify the validity of the proposed secure transmission strategy and the correctness of the theoretical derivation,and then analyze the impact of key system parameters such as the number of antennas,the number of eavesdropping users,and channel fading on the security performance of the system.3.Analyze the performance of the satellite communication system under the non-orthogonal multiple access(NOMA)scheme.First,considering the effects of the satellite antenna gain and satellite link loss,a satellite communication system model based on uplink NOMA transmission technology is established,and the expression of the end-to-end output signal-to-noise ratio of the target user under the AF protocol is obtained.Secondly,under the condition that both the uplink and downlink of satellite communication obey the shadowed-Rician distribution,based on the output signal-to-noise ratio expression,a closed expression for the traversal and rate of the satellite communication system using uplink NOMA transmission technology is derived.Finally,computer simulation not only verifies the correctness of the theoretical analysis,but also shows that the satellite communication system using NOMA technology in the uplink has better advantages through comparison with Orthogonal Multiple Access technology.System capacity,resource utilization and user fairness are also higher.Therefore,NOMA technology has great potential in enhancing the capacity of satellite communication systems.