一种基于迭代最小二乘法的精确同步方法

A Precise Synchronization Method Based on Iterative Least Square Algorithm

最小二乘拟合鉴相曲线的方法可以实现精确同步,但其对粗同步要求苛刻且不能有效对抗频偏。该文通过分析证明当粗同步误差在前后各半个码片周期内时,最小二乘法的测量值介于零和实际值之间。根据该特性提出基于迭代最小二乘法的精确同步方法,并引入分段相关取模策略,以达到抗频偏效果。理论分析表明该方法能够有效消除噪声的影响,并且在分段长度不大的情况下具有很强的抗频偏能力。仿真结果表明该方法具有很强的抗频偏和抗噪声能力,并且在粗同步误差覆盖前后半个码片范围时依然具有很高的测量精度。

Precise synchronization can be achieved by fitting phase discrimination curve exploiting Least Squares （LS）. However, this method not only has very high requirement of coarse synchronization, but also can not counteract frequency- offset effectively. It is analyzed and proved that the measured value of LS is between zero and real value as coarse synchronization error is between the earlier and later chip. Accordingly a precise synchronization method based on iterative least squares is proposed and a modulus of split correlation strategy is also introduced in this paper to counteract frequency-offset. Theoretical analysis shows that this method can outstandingly eliminate influence of noise as well as frequency-offset with short segments. Besides its strong anti frequency-offset and noise capability, the proposed method still has very high measurement precision as the error of coarse synchronization covers the earlier and later half chip according to simulation results.