基于OFDM的高速电力线载波通信系统设计

摘要

随着智能电网的提出和推广,基于电力线载波的通信系统因成本低、通信速率高等优点得到了广泛使用.然而电力线载波通信存在频率选择性衰落、多径衰落以及脉冲干扰等不利条件,为了给智能电网提供高速可靠的通信手段,设计了基于正交频分复用的高速电力线载波通信系统,采用粗步捕获+精准同步的两次同步技术.为了消除大动态噪声和干扰对同步绝对门限设定的影响,提出一种窗口滑动方法,在等分窗口内用后一部分的能量与前一部分的能量的比值作为判决变量,消除大动态噪声和干扰的影响.仿真结果表明,在电力线载波环境下,设计的方案能够很好地解决频率选择性问题,同时具有显著的抗脉冲干扰和多径衰落能力.%With the development and popularization of the smart grid,the power line carrier(PLC) communication system has been widely used because of its low cost and high communication speed.However,there are such disadvantages,such as frequency selective fading,multipath fading and pulse interference,in PLC communication.In order to provide high-speed and reliable physical layer communication means for smart grids,the high speed PLC communication system based on OFDM is designed,the two synchronization technologies that coarse step acquisition and precise synchronization are adopted.In order to eliminate the influence of large dynamic noise and interference on the synchronization absolute threshold setting,a window sliding method is proposed.In an equal window,the ratio of the energy of latter part to the energy of the front part is used as the decision variable to eliminate the effect of dynamic noise and interference.The simulation results show that the proposed method can solve the frequency selectivity problem well in the environment of PLC.At the same time,it also has the ability of resisting imoulse interference and multioath fading.