OFDM系统中的全数字频偏跟踪环
All Digital Frequency Offset Tracking Loop in OFDM Systems
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摘要: 频偏跟踪是影响到OFDM系统性能的关键技术之一。该文基于迟早门类型的锁相环，提出了一种新的适合于OFDM系统的频偏跟踪算法。研究表明，该算法既能在AWGN信道中也能在多径衰落信道中完成频偏跟踪工作。并且其低信噪比下的频偏跟踪性能比一般的频偏跟踪方法好几个数量级。如果系统对定时估计的要求不是特别高，该算法还能实现定时偏移和频率偏移的联合跟踪。Abstract: Frequency offset tracking is one of the key technologies that affect OFDM systems performance. Based on early-late gate phase-locked loop, a new frequency offset tracking algorithm is proposed in this paper. The study shows that the algorithm can complete frequency offset tracking in AWGN channel and multipath fading channel. Furthermore under lower SNR the performance of the proposed algorithm is better by several orders compared to the common frequency offset tracking methods. If the systems have not very special requirements on timing tracking this algorithm also can complete joint tracking of frequency and timing.
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