基于Zadoff-Chu序列的移动数字电视接收系统频偏估计算法

针对移动数字电视接收系统频偏估计算法存在的频偏估计均方差和误码率高等问题，提出了一种基于Zadoff-Chu （ZC）序列频偏估计算法。首先通过建立信号模型，利用仿真分析了载波频率偏差对接收系统影响；其次，信标结构中的两个同步信号以半周期形式选择ZC序列，1个导频符号序列由2个ZC序列构成。因此，接收端接收的2个符号是完全相同的ZC序列，通过对1个ZC序列半周期进行自相关运算并计算频偏值，即可以完成对整个周期符号的频偏估计。仿真结果表明，相比于其它算法，频偏估计均方差可降低20~30%，增益提升约2dB。

Mobile Digital TV Receiver System Frequency Offset Estimation Algorithm Based on Zadoff-Chu Sequence

The current frequency offset estimation algorithm of mobile digital TV receiver system has these disadvantag-es that the variance and bit error rate (BER) are very high. Frequency offset estimation algorithm based on Zadoff-Chu (ZC) sequence was presented to work out related issues. Firstly,the impact of the carrier frequency offset for receiving system was analyzed by simulation. Secondly,the ZC sequence in the form of a half cycle was chosen in two synchronization signals of the beacon formation and a pilot sequence was constituted by two ZC sequence. There-fore, two symbol of the reception terminal were the same ZC sequence. Then, by calculating the autocorrelation and the frequency offset value of a ZC sequence in a half cycle,the frequency offset estimation of entire cycle symbol was completed. The simulation result indicated that the frequency offset estimation variance is decreased 20~30%, BER is lower,and the gain is improved 2dB comparing with other traditional algorithms.