Research On Precoding Method For Multi-Beam Broadband Satellite Communication System

Multi-antenna technology has been widely used in satellite communication systems due to its advantages of high capacity,high speed and strong anti-interference ability.However,the introduction of this technology has made the problem of interbeam interference in satellite links more and more serious,which affects the transmission rate of the system.How to eliminate inter-beam interference is a key issue that needs to be solved urgently.Since the inter-beam interference problem is similar to the inter-cell co-channel interference problem in terrestrial cellular communication networks,and the Precoding technology is an effective method to solve inter-cell interference.So the precoding technology can be extended to multi-beam satellite systems to overcome inter-beam interference,thereby improving the performance of satellite communication systems and further creating a high-quality satellite communication link environment.Therefore,this topic focuses on the precoding method of multi-beam satellite communication systems,which has extremely important research value and practical significance.Firstly,the spatial propagation characteristics of satellite communication channels are introduced,including the principles and effects of various factors.At the same time,several classical satellite channel fading models are analyzed in detail,which are described from the basic concepts,structural components and applicable scenarios.And a brief overview of the rain attenuation factors in Ka-band satellite communications is given.Finally,the multi-beam satellite channel model is studied,including the advantages of the multi-antenna model and the main features of the satellite channel,paving the way for the performance study of the fourth chapter precoding technology.Secondly,it mainly introduces the theoretical basis of precoding technology,including basic principles,classification standards and channel state information(CSI)acquisition,etc.It focuses on the analysis of the principles and performance of several common linear precoding algorithms.At the same time,the design problem of robust linear precoding under non-ideal CSI is studied when there is channel estimation error in communication link.Two kinds of precoding optimization algorithms based on MMSE criterion are proposed for the problem that channel estimation error affects system performance.By constructing the error model,the optimal solutions of two optimization algorithms are derived.Finally,the performance of the error rate,system transmission rate and mean square error of the precoding algorithm between ideal and non-ideal CSI are analyzed by simulation in Rayleigh channel,the robustness of the proposed algorithm are further verified.Finally,the importance of precoding technology applied to multi-beam satellite systems is described.Three satellite precoding implementation methods are introduced,including the system models of various methods,their advantages and disadvantages,and the corresponding system block diagrams are given.The multi-beam satellite system model is deeply analyzed,and the composition structure,principle and main influencing factors of the channel are expounded.Finally,the error rate of various linear precoding algorithms for ideal CSI is simulated and analyzed under the Rice shadow channel.At the same time,when there is channel estimation error in the communication link,the algorithm proposed in this paper is applied to the multi-beam satellite system.The performance advantages of the proposed algorithm in the multi-beam satellite systems are verified by the simulation of the bit error rate and the system transmission rate.