研究了存在载波频偏的正交频分复用( OFDM) 放大转发( AF) 中继系统的中断概率和误码率． 首先给出了存在载波频偏时系统信噪比及其概率分布，然后推导出瑞利信道中存在载波频偏时系统中断概率和误码率的闭合表达式． 为了更加直观，文中还给出了大信噪比时系统中断概率和误码率的错误下界，并通过数值仿真来验证理论分析的正确性．理论分析和仿真结果表明: 存在载波频偏时，即使在大信噪比情形下系统的中断概率和误码率并不趋于 0，而是趋于错误下界; OFDM AF 系统对载波频偏很敏感，随着信噪比的增大，系统性能随着载波频偏的增大迅速变差．

This paper deals with the bit error rate (BER) and outage probability of a dual hop OFDM AF relay sys-
tem in the presence of carrier frequency offsets (CFO)． First，the signal-to-noise ratio (SNR) of the system and its probability distribution are put forward in the presence of CFO，and then the close-form expressions of the BER and outage probability of the system are derived with CFO in Ｒayleigh fading channels． In order to provide more insights，the error floors of the BEＲ and outage probability of the system are also obtained． Moreover，a theoretical analysis is proved to be correct by simulation． The theoretical analysis and simulation results indicate that，in the presence of CFO，the BER and outage probability of the system tend to be the error floor but not zero even at a high SNＲ，and that the performance of OFDM AF relay system is very sensitive to the CFO，and the system performance gets worse rapidly with the increases of the CFO and the SNR．