OFDM系统的对数似然比最大化盲频偏估计算法  

A Log-likelihood Ratio Maximization Blind Frequency Offset Estimation Algorithm in OFDM Systems

作　　者：任雪峰[1] 蒋宇中[1] 刘旋[1] 

机构地区：[1]海军工程大学通信工程系,武汉430033

出　　处：《电讯技术》2010年第12期58-62,共5页Telecommunication Engineering

摘　　要：为了消除短波OFDM通信中的频率偏移问题,对差分OFDM信号进行了分析,并对最大后验概率(MAP)译码的性质进行了研究,提出了一种似然比最大化的迭代盲频偏估计算法。由于该算法充分利用了软译码得到的似然比信息,因此可以实现最优信号检测。计算机仿真证明了该算法的有效性。进行了短波OFDM信号通信实验,得到了实测数据。实测数据检测结果表明,该算法的误码率性能随着迭代次数的增加而提高,且一发两收系统性能要比单发单收系统性能至少提高2 dB。In order to remove the frequency offset in HF OFDM communications, the differential OFDM systems are analysed, and the property of MAP decoding is studied. A log-likelihood ratio maximization blind frequency offset estimation algorithm is proposed. This algorithm can achieve the best demodulation because the likelihood ratio of information is used adequately. The simulations show that this algorithm is effective. HF communication experiment is performed, and practical information is achieved. Using this algorithm to demodulate practical in- formation demonstrates that this algorithm can enhance the BER performance with the increasing iterative times, and the performance of one-transmitter/two-receiver system is better than that of one-transmitter/one-receiver system at least 2 dB.

关 键 词：短波通信 差分OFDM调制 MAP译码 盲频偏估计 

分 类 号：TN914[电子电信—通信与信息系统]