符号定时偏差对OFDM系统性能的影响

Effect of Timing Synchronization Errors on the Performance of OFDM Systems

针对符号定时偏差对OFDM系统的影响进行了分析,推导了AWGN信道下定时偏差与信噪比损失的近似关系式,并通过仿真对分析结果进行了验证。研究表明,由于采用循环前缀,符号定时适度超前不会对系统性能造成大的影响,而定时滞后则会引入符号间干扰,使系统性能恶化。因此符号定时不一定要很精确,但一定要特别准确。

Mathematical analysis of the effect of timing errors on the performance of an OFDM receiver is provided. Approximate expression for the Signal - to - Noise Ratio （SNR） performance degradation in the presence of timing errors is derived for AWGN channel. The analysis results are testified by simulation. It is shown that system performance is not sensitive in case of timing errors to the left, but degenerates remarkably in case of timing errors to the right. So the symbol timing synchronization may not be exact but must be correct.