FH-OFDM系统自相关频偏估计的敏感性研究

研究了FH-OFDM系统中频率偏移估计的问题,与传统的OFDM系统不同,在FH-OFDM系统中,必须确认在完成频偏估计之前的频率变换需要达到的精度.通过计算接收信号与接收机中的跳频频率合成器产生的频率之间的跳频时间偏移(FHO)和跳频相位偏移(PHO)得到跳频频率的精确性.在多径衰落信道中特定FHO和PHO值的情况下,对系统中自相关算法性能进行了仿真,结果与理想跳频情况下的性能对比表明,基于自相关原则的频偏估计算法对抗不超过跳频时间的一半的频偏非常有效.

Sensitivity of autocorrelation frequency offset estimation in a FH-OFDM system

A new aspect of carrier frequency offset (CFO) estimation is studied in a frequency-hopping (FH) orthogonal frequency division multiplexing (OFDM) system.Unlike in a traditional nonhopped OFDM system,in FH-OFDM system it is important to verify how accurately frequency-switching must be performed before the CFO estimation can take place with adequate performance.The accuracy of frequency-switching is evaluated through frequency-hopping timing offset (FHO) and frequency-hopping phase offset (PHO) between the received signal and the signal produced by the local frequency-hopping synthesizer of the receiver.The performance of selected autocorrelation algorithms is simulated in multi-path fading channel under the FHO and PHO,and the results are compared with the performance of ideal frequency-switching and the corresponding analytical Cramer-Rao bound.It is found that the CFO estimators based on autocorrelation principle are quite robust to the FHO less than half the hopping period.