G3-PLC系统定时同步-信道估计联合设计与实现

Combined Design and Realization of Timing Synchronization and Channel Estimation for G3-PLC System

由于低压电力线在传输信号过程中受到噪声、多径干扰和频率选择性衰落等影响,造成定时同步不准确,容易产生漏检和误判。针对G3-PLC标准,提出了一种定时同步和信道估计联合设计方案,通过与本地序列进行两级互相关来实现符号的定时同步,并利用相关器输出直接进行信道估计。该方案提高了定时同步的精度,扩大了其正常工作的信噪比范围,并且简化了信道估计实现方案。最后完成了联合设计的硬件实现,利用FFT计算互相关,有效降低了计算量,减少了硬件资源开销,同时实现了多种CELENEC频段传输模式兼容。

Since low voltage power lines are affected by noise pollution, multi -path propagation and frequency selec- tive fading in the process of signal transmission. It results in inaccuracy of timing synchronization, leak detection and misjudgment. A combined design scheme of timing synchronization and channel estimations is proposed in this paper under the G3 - PLC standard. Firstly, second - order cross - correlation with the local pilot is acquired to realize tim- ing synchronization. Then the output of the correlator is used directly to achieve channel estimation. This design scheme improves the accuracy of timing synchronization and expands the range of SNR in normal work. Besides it sim- plifies the scheme of channel estimation. At last the hardware of the combined design scheme is accomplished. It uses FFT to calculated cross - correlation, which effectively reduces the computation and the amount of hardware re- sources. Meanwhile, compatible transmission mode of various CELENEC band is brought out.