Research On CPF-OFDM Signal Detection And Reception Technology

Orthogonal Frequency Division Multiplexing(OFDM)technology is used in many industries due to its high frequency utilization and good resistance for multipath.Among them,as a standard OFDM signal,Cyclic Prefix OFDM(CP-OFDM)signal is the most common OFDM signal.Cyclic Prefixed Free OFDM(CPF-OFDM)signal,as a non-standard OFDM signal,has a great potential for development due to its high power efficiency.Currently,i PSTAR,the world's largest broadband satellite,uses CPF-OFDM signal for transmission.This paper studies the detection and reception technology of CPF-OFDM signal for i PSTAR signal in non-cooperative scenarios,mainly including the following contents:In the first chapter,the background and significance of non-standard OFDM signal detection and processing technology are introduced.Then,the research status of OFDM target signal detection and classification and OFDM signal time-frequency synchronization technology are analyzed.And the characteristics and shortcomings of each algorithm are summarized.Finally,the main research content and structure of this article are summarized.In the second chapter,the CPF-OFDM signal parameters and detection and reception scheme are designed.Firstly,the basic principle of OFDM signals is described,and the structural characteristics of three OFDM signals are summarized.Then,the CPF-OFDM signal parameters based on i PSTAR signal are designed,and the modulation mode and frame structure are explained.Then,the CPF-OFDM signal detection and processing scheme is proposed,and the functions of each module are briefly explained.In the third chapter,CPF-OFDM target signal detection and classification technology are studied,including target signal existence detection,OFDM signal and single carrier signal inter-class recognition and OFDM signal intra-class recognition.Simulation results show that the correct detection probability of CPF-OFDM signal is more than 99%,and the inter-class and intra-class recognition probability are more than95%in the additive white Gaussian noise channel and the Rice fading channel with SNR is not less than 2d B.The fourth chapter studies the time-frequency synchronization technology of CPF-OFDM signal,proposes the CPF-OFDM signal acquisition algorithm based on joint decision of multi-symbol and multi-frequency point,and studies the signal frequency offset and timing estimation algorithm.Simulation reveals that the proposed time-frequency synchronization algorithm has an excellent performance.When the SNR is not less than 2d B,the Normalized Root Mean Square Error(NRMSE)of frequency offset estimation is less than10^-6,and the time offset estimation Error is about 0.0128samples.In the fifth chapter,the detection performance of CPF-OFDM signals is simulated comprehensively.Firstly,the detection and reception architecture of CPF-OFDM signals is given,and the algorithm of each module is determined.Then,the error vector amplitude and demodulation symbol error rate of each subcarrier in the data slot are tested,and the test results are basically consistent with the theoretical performance.Finally,the comprehensive simulation analysis of target signal detection and classification,synchronization and demodulation performance are given.The results show that the detection and classification algorithm and synchronization algorithm used in this paper have good performance.The synchronization estimation error almost has no effect on the demodulation performance,and the blind demodulation performance is close to the ideal synchronization demodulation performance.