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OFDM技术是LTE-TDD系统的关键技术,具有频谱利用率高、有效对抗符号间干扰和载波间干扰、易于硬件实现等优点。但OFDM系统对于频率和时间同步的要求较高,频率偏差将导致OFDM系统子载波正交性受到破坏,从而导致整个系统性能下降。本论文从LTE-TDD系统同步序列自身特点出发,利用整数倍频偏和定时偏差的内在关系,提出了一种联合整数倍频偏和定时偏差估计的同步算法。通过该算法,可以提高整数倍频偏和定时估计的检测精度。
OFDM technology is the key technology of LTE-TDD system, with the advantages of high spectral efficiency, effective countermeasure against inter-symbol interference and inter-carrier interference and easy realization of hardware. However, the requirements of OFDM system for frequency and time synchronization are high, and the frequency offset will result in the destruction of the orthogonality of subcarriers of the OFDM system, resulting in a decrease of the overall system performance. Based on the inherent characteristics of the synchronization sequence of LTE-TDD system, this thesis proposes a synchronization algorithm based on integer multiples and timing deviations. Through this algorithm, we can improve the detection accuracy of integer multiple frequency offset and timing estimation.