摘要
该文将单载波中的Gardner位同步方法应用于OFDM系统中,以解决OFDM系统中的采样率同步问题。同步环路由定时误差提取、环路滤波器和插值器3部分组成。由于采样率偏差基本恒定,本文将环路滤波器用线性最小二乘拟合代替。拟合过程用递推实现以降低运算量。经过分析,最小二乘拟合可使采样率偏差的估计误差随拟合的符号数以立方律减小。但最小二乘拟合在实际中存在两个问题:首先,由于温度等因素,采样率偏差会缓慢变化,并不恒定;其次,随着时间的积累,递推中间变量总会溢出。该文给出了相应的解决方法,只需定期修正递推的中间变量,即可通过限制拟合的时间跨度并定期变换坐标系,解决了以上两个问题。
Gardner bit synchronization method in single carrier is applied to OFDM system,to complete sampling rate synchronization.Gardner loop is composed of timing error estimator,loop filter and interpolation.The loop filter is replaced by linear least-square fitting which is achieved by recursion in order to reduce computational complexity.The estimation error of sampling rate can be reduced in cubic law.But there are two problems in practice when using least-square fitting.First,the sampling rate is not constant,which will change slowly by the temperature.Second,the intermediate variables will overflow in recursion.So the intermediate variables are modified periodically to limiting the time span and change the coordinate to solve the two problems.
出处
《电子与信息学报》
EI
CSCD
北大核心
2011年第4期864-868,共5页
Journal of Electronics & Information Technology
基金
航空科学基金(2009ZC52036)资助课题