CAJ | 학술논문

针对正交频分复用( OFDM)系统对同步错误率和频率偏移敏感的问题，提出了一种叠加共轭对称训练序列的OFDM系统时间和频率同步方法。该同步方法将快速傅里叶逆变换( IFFT)调制后的序列构成具有共轭对称特性的训练序列，并叠加到OFDM数据符号上；在接收端，利用叠加训练序列和融合循环前缀信息来获取OFDM系统同步信息。理论分析和仿真表明：在信噪比为5 dB时，该同步算法定时同步正确概率已接近100%；在信噪比为4 dB时，频偏估计精度可以达到10-4；该同步算法不仅具有更好的同步性能，而且节省系统的有效带宽以及降低系统的计算法复杂度。
침대정교빈분복용( OFDM)계통대동보착오솔화빈솔편이민감적문제，제출료일충첩가공액대칭훈련서렬적OFDM계통시간화빈솔동보방법。해동보방법장쾌속부리협역변환( IFFT)조제후적서렬구성구유공액대칭특성적훈련서렬，병첩가도OFDM수거부호상；재접수단，이용첩가훈련서렬화융합순배전철신식래획취OFDM계통동보신식。이론분석화방진표명：재신조비위5 dB시，해동보산법정시동보정학개솔이접근100%；재신조비위4 dB시，빈편고계정도가이체도10-4；해동보산법불부구유경호적동보성능，이차절성계통적유효대관이급강저계통적계산법복잡도。
The orthogonal frequency-division multiplexing ( OFDM) system is sensitive to synchronization error rate and frequency offset. This paper proposes a timing and frequency synchronization method with the superim-posed conjugate symmetric training sequences to solve the problem. This synchronization method utilizes the in-verse fast Fourier transform( IFFT) modulated sequences to construct training sequences with conjugate symmet-ric properties. Then the training sequences are superimposed on OFDM data symbols. At the receiver,the syn-chronization information is obtained by superimposed training sequences and combining the information of cyclic prefix. Theoretical analysis and simulation show that:with signal-to-noise ratio(SNR) 5 dB,the probability of correct timing synchronization achieves nearly 100%,and with SNR 4 dB,the precision of the frequency offset estimation can be as high as 10-4;this synchronization algorithm has better synchronization performance,at the same time,it saves system bandwidth effectively and reduces computational complexity.