Research On Performance Analysis And Resource Allocation Algorithms Of Integrated Satellite-Terrestrial Network

With the rapid development of intelligent terminal technology and wireless communication system,the amount of user data flow is increasing rapidly,and the cellular communication system is facing great challenges.Through the cooperation between satellite network and cellular network,the load of cellular communication system can be effectively reduced.In addition,satellite communication systems can be used to provide users with network access services in the areas where cellular infrastructure cannot be easily deployed.In view of the advantages of wide coverage,large capacity and high reliability of satellite communication system,the effective integration of satellite and ground networks has become an inevitable trend.Due to the high path loss and transmission obstacles between satellite ground links,the communication performance will be limited.Relay cooperation technology can be applied in hybrid satellite-terrestrial network,resulting in hybrid satellite-terrestrial relay network,so as to improve the quality of user service.This thesis studies the transmission performance and resource allocation algorithms of hybrid satellite-terrestrial relay network.The main contents are as follows.Considering the hybrid satellite-terrestrial relay network using amplify and forward(AF)protocol,this thesis first analyzes the statistical characteristics of satellite channel and terrestrial channel,and evaluates the Amount of Fading(Ao F)index of satellite land cascade channel.Secondly,for the non-ideal scenario of hardware impairments and imperfect channel state formation(CSI),the performance of hybrid satellite-terrestrial relay network is evaluated.Through the model of hardware impairments and the analysis of channel estimation error,the cumulative distribution function(CDF)of signal-to-noise ratio at the receiver is obtained respectively,and the closed expression of outage probability is derived.Finally,based on the signal-to-noise ratio obtained in the hardware impairments scenario,the problem of energy efficiency maximization is formulated.The modeled nonconvex problem is solved by using dinkelbach transformation method,and the optimal power allocation scheme of satellite and relay is obtained.In order to improve the capacity and spectral efficiency of the hybrid satellite-terrestrial relay network system,this thesis further considers applying non-orthogonal multiple access(NOMA)technology in the network,and proposes a data transmission scheme.Based on the proposed scheme,this thesis assumes the satellite and terrestrial cellular network share the spectrum,and studies the impact of co channel interference(CCI)on network performance.By modeling CCI and analyzing the statistical characteristics of CCI,the closed-form expressions of average symbol error rate and outage probability of NOMA users are further derived.In particular,for NOMA strong users,the influence of imperfect SIC on its symbol error rate is evaluated.In addition,since it is difficult to obtain accurate CSI in satellite communication,this thesis uses the statistical information of channel and CCI to model the maximization problem of satellite mean energy efficiency(MEE).The primal fractional programming problem is transformed by applying Charnes Cooper method and solved by Lagrange dual method.Finally,the optimal satellite power allocation scheme is proposed.Monte Carlo simulations show that the numerical results deduced in this thesis have a favourable fit with the simulation results,which proves the effectiveness of the derivation results.