The Research Of Synchronization And Compensation Techniques Of Non-idealities In OFDM High Speed Data Transmission Systems

High-speed broadband wireless data transmission system is the trend of the future development of military communications systems.OFDM modulation technology is adpoted in high-speed data transmission systems to achieve higher data rate of several Gbps,the research on synchronization and compensation of non-idealities,is of great significance in the performance optimization and implementation simplification for high-speed broadband wireless data transmission systems.This paper is based on the new research items named 10 Gbps microwave high-speed data transmission systems,two main issues in OFDM high-speed data transmission systems,synchronization technology and compensation techniques of non-idealities were deeply studied,the main results achieved in this paper are as follows:1.The influence of synchronization errors on OFDM systems were analyzed,and the theoretical performance of a variety of joint synchronization algorithms were simulated and analyzed.Focusing on the problem that the timing measure function in joint synchronization algorithms base on the cyclic prefix has the large side lobes,an improved joint synchronization was proposed,which suppressed side lobes effectively and greatly improved the timing estimation accuracy.The synchronization techniques based on training symbols were simulated and analyzed,considering the advantages and disadvantages of several kind of synchronization algorithms,we considerred to obbtain fast symbol timing based on training symbol with symmetric structure,then estimate frequency deviation based on cyclic prefix,or we could obbtain the frequency offset estimation using the repeated parts of training symbol,the fast convergency and low implementation complexity which were fitted in high-speed data transmission systems.2.The influence of phase noise and IQ imbalance on OFDM systems was analyzed,and theoretical performance of a variety of phase noise and IQ imbalance compensation algorithms were simulated and analyzed.Comparing these algorithms in spectral efficiency,computaional complexity and performance,is of great significance for high-speed data transmission systems.3.Focusing on the problem of co-existense of phase noise and IQ imbalance in OFDM systems,we proposed a new method based on one training symbol to jointly combat phase noise and IQ imbalance,the theoretical performance of the joint compensation algorithms were simulated and analyzed,which proves to be of great advantages in spectral efficiency,computaional complexity and system performance.This method is hopefully applying in real high-speed data transmission systems.This paper focuses on the study of synchronization and compensation of non-idealities in OFDM high-speed data transmission systems,several synchronization and compensation algorithms which suited the high-speed data transmission systems are proposed,the research provides an important reference and solve basis for synchronization and compensation of non-idealities and also with significant engineering reference in the implementation of high-speed data transmission systems.