UFMC系统中的载波频率同步技术

Carrier frequency synchronization technology in UFMC

针对UFMC系统对频率偏差敏感的问题,提出一种适合用于UFMC系统的频率同步算法。为了保留UFMC系统的良好特性、降低UFMC中滤波器的设计复杂度,该算法设计了一种子带间正交的导频序列,并采用非线性最小二乘(NLS)法进行CFO估计。通过序列构造和计算该构造序列与估计信号的相关性对算法进一步改进,使得低信噪比下的估计性能得到改善。理论分析和仿真表明,在高斯和瑞利衰落信道下,子带间正交导频序列的误码率、CFO性能均优于全1导频序列;在低信噪比环境下,改进算法的CFO性能优于NLS算法。

In view of the problem that the universal filtered multi-carrier（UFMC） system is sensitive to carrier frequency offset, a frequency synchronization algorithm was proposed. For the sake of keeping good features of UFMC system and reducing the complexity of filter design, the algorithm designed a pilot sequence which sub-bands are orthogonal, and used the non-linear least square algorithm（NLS） to realize the frequency offset estimate. In order to further improve the performance of algorithm in low signal to noise power ratio（SNR） environment, the receiver could process data by constructing sequence and calculating the correlation of estimated signal. Simulation results demonstrate that the designed pilot is superior to all-one pilot in terms of both bit error rate（BER） and CFO performance over additive white Gaussian noise（AWGN） and rayleigh fading channel. And in low SNR environment,the improved algorithm has better performance than NLS algorithm under CFO.