一种克服载波频偏的帧同步新方法

研究了基于对接收信号序列和本地序列进行互相关的帧同步方法。当接收信号存在较大载波频偏时,互相关结果的峰值与无载波频偏的情况相比将显著减小。因此,提出了一种基于分段互相关的帧同步方法,首先将相关窗分为数段,分别对各段接收信号子序列和本地子序列进行互相关,并将各段的相关结果合并后作为帧同步检测量。仿真结果表明,提出的帧同步方法在存在较大载波频偏的情况下仍然能够准确检测出帧起始位置。此外,该方法仅需在滑动互相关器的基础上添加少量的乘法器和加法器,因而具有较低的实现复杂度和较高的资源率用率。

A novel approach of frame synchronization in presence of frequency offset

This paper studies the frame synchronization methods based on the cross-correlation between received signal and local sequence. When the carrier frequency offset of received signal is large, the peak value of cross-correlation would decrease significantly compared to that with zero carrier frequency offset. To solve the problem, an approach based on segmental cross-correlation is proposed. It first divides the correlation window into several segments and calculates the correlation value of each segment separately, and then combines these values to get the measure of frame synchronization. The simulation results shows that the approach proposed can detect the start of frame precisely in presence of large carrier frequency offset. Besides, low complexity of realization and high utilization of hardware resource is achieved as it only needs to add a few multipliers and adders to the conventional slide cross-correlator.