预均衡OFDM系统中定时误差的性能影响

仿真研究了整数倍和分数倍定时误差对于预均衡OFDM系统的性能影响，结果表明：定时误差将造成解调数据的相位旋转, 并导致预均衡系统性能的快速下降，其程度由系统的子载波数和误差精度等因素决定；仿真显示，在QPSK，1/3Turbo编码，90 ms交织，子载波数4 096，信道模型为ITU RM.1225 车载30 km/h的条件下，每当误差增加1/16的归一化定时误差，性能下降约1 dB。
关 键 词 预均衡OFDM; 预均衡因子; 定时误差; 相位旋转因子

Abstract This paper investigated the impact of the timing error on the receiver BER performance in the pre-equalization OFDM systems through simulations. The results showed that the timing error would bring on the phase rotation of demodulation data, and degrade the system performance critically. So it must be revised by assistant methods. The timing error and the number of sub-carriers together decide the degradation. Simulations showed that the performance would fall down 1 dB every 1/16 normalized timing error.
Key words pre-equalization OFDM; pre-equalization factor; timing error; phase rotation coefficient