基于自相关系数插值的迭代符号定时同步

发布时间：2018-01-19 05:14

本文关键词： 符号定时估计匹配滤波自相关系数迭代高斯插值　出处：《工程科学与技术》2017年03期 　论文类型：期刊论文

【摘要】：在无线数字通信系统中,全数字化接收机以固定的时钟进行采样,容易出现符号采样偏差,需要在接收端进行估计并补偿。针对符号定时估计的问题,提出了一种基于自相关系数插值的迭代符号定时同步算法。该算法分为两个步骤:粗同步与精同步。粗同步先利用零相滤波器或三相滤波器组对接收信号进行匹配滤波,再利用滑动自相关的方法对同步头序列进行相关运算,当超过同步门限时,开始进行同步跟踪对自相关系数进行峰值搜索,以确定精同步搜索区间。精同步直接在搜索区间内进行迭代搜索,迭代过程中需要先根据估计的时延值生成群时延的匹配滤波器以对接收信号进行补偿,再利用最小二乘逼近函数度量,同时,采用高斯插值的方法提高搜索速度以获取精确的估计结果。与传统算法相比,该算法降低了同步搜索过程中的计算复杂度,同时利用迭代搜索易于实现高精度的符号定时同步。仿真结果表明:对于长度为64的同步头序列,在高斯白噪声信道条件下,信噪比 2 dB时,该算法利用两次迭代即可逼近克拉美罗界;在信噪比为10 dB,针对±1/2符号周期内的采样偏差,本文算法的MSE性能均优于升余弦插值、MMSE插值与多相滤波器组算法;在瑞利信道、CCIR中等信道以及CCIR坏信道下也能进行有效的估计,适合无线数字通信系统的信道环境。
[Abstract]:In the wireless digital communication system, the all-digital receiver samples with a fixed clock, which is prone to the symbol sampling deviation, which needs to be estimated and compensated at the receiver, aiming at the problem of symbol timing estimation. An iterative symbol timing synchronization algorithm based on autocorrelation coefficient interpolation is proposed, which is divided into two steps:. Rough synchronization and fine synchronization. Coarse synchronization uses zero-phase filter or three-phase filter bank to filter the received signal. Then the sliding autocorrelation method is used to perform correlation operation on the synchronous head sequence. When the synchronization threshold is exceeded, the peak value of the autocorrelation coefficient is searched by synchronous tracking. In order to determine the precision synchronization search interval, the precision synchronization searches directly in the search interval. In the iterative process, the matched filter of group delay should be generated according to the estimated delay value to compensate the received signal. At the same time, Gao Si interpolation method is used to improve the search speed to obtain accurate estimation results, compared with the traditional algorithm. The algorithm reduces the computational complexity in the synchronous search process, and it is easy to achieve high precision symbol timing synchronization by iterative search. The simulation results show that the synchronization header sequence is 64 in length. Under the condition of Gao Si white noise channel, the signal-to-noise ratio (SNR) is 2 dB, and the algorithm can approach the Clemero bound by using two iterations. When the SNR is 10 dB, the MSE performance of the proposed algorithm is superior to that of the raised cosine interpolation and polyphase filter banks for the sampling deviations within 卤1/2 symbol periods. In Rayleigh channel, CCIR medium channel and CCIR bad channel can also be effectively estimated, which is suitable for wireless digital communication system channel environment.
【作者单位】：哈尔滨工程大学信息与通信工程学院;武汉船舶通信研究所;
【基金】：船舶工业国防科技预研基金资助项目(11J3.4.2)
【分类号】：TN713;TN911.7;TN914
【正文快照】： 在无线数字通信系统中,传输信号容易受到时延、相位偏移、频率偏移以及衰落的影响,需要在接收端进行信号补偿[1]。符号定时采样需要信号在其眼图张开最大的时刻采样,以保证噪声与干扰最小化[2];而全数字化接收机以固定的时钟进行采样[3],容易出现符号采样偏差。符号采样偏差会

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