基于前导序列的PLC系统定时同步技术研究

Research on the timing synchronization technology for PLC based on preamble sequence

电力线建设初期并没有考虑通信的要求,其信道环境恶劣,子载波间的正交性就会遭到破坏,同时在接收端会出现符号定时偏差,引起符号间干扰,因此对OFDM符号的频率偏差和符号偏差进行有效的估计和补偿具有非常重要的意义。根据G3-PLC特有的帧结构,利用其前导序列之间的相关性,采用两重相关检测方法对系统频偏及符号偏差进行了有效的补偿,最后通过Monte Carlo方法对其进行了仿真验证。结果显示,所采用的同步算法可以很好地对系统失步进行补偿,并且算法实现简单,信道适应性强。

Because people do not consider the requirement of communication in the construction of power line, that resulting in the poor channel environment and the orthogonality between the sub-carriers are damaged. Meanwhile, the symbol offset will occur in the receiving terminal, which will cause the inter symbol interference, so it has very important significance to estimate and compen- sate the frequency offset and symbol offset for OFDM symbol effectively. According to the special frame structure of G3-PLC, this paper uses the double correlation detection method to compensate the frequency offset and symbol offset of the OFDM system. At last, the algorithm is confirmed by Monte Carlo approach. The results indicate that the synchronization algorithm used in this paper can be very good to compensate for the frequency offset and symbol offset of the system, and the algorithm is very simple and has strong adaptability to the channel.