正交频分复用(OFDM)是电力线高速数据传输的有效调制技术.而电力线信道的时频双选择性造成OFDM系统的频率偏移,导致载波间干扰(inter-carrier interference,ICI).为准确掌握信道特性,提出了基于离散长球序列-基扩展模型(DPSS-BEM)的宽带电力线载波OFDM信道估计方法.采用二维DPSS-BEM对电力线信道进行建模,将电力线信道视为二维正交分量的线性加权,并利用导频位置的训练信息和最小二乘法估计权值.仿真表明,该方法能有效地跟踪电力线信道变化,改善信道的归一化均方误差和误码率性能,以便有针对性地采取措施,减少载波间的相互干扰.
OFDM is an effective modulation technology to realize high-speed data transmission on power lines.The time-frequency selectivity of power line channel will lead to frequency shift of the OFDM system,which also yields ICI.To master the channel characteristics accurately,the broadband power line carrier OFDM channel estimation based on DPSS-BEM is proposed in this paper.In this method,the power line channel is modeled with using two-dimensional DPSS-BEM and regarded as the linear weighting of two-dimensional orthogonal components.The channel variation during OFDM symbol is treated as the variety of weights,and the training information from pilots and the least squares method are used to estimate weights to complete channel estimation.The simulation results show that the method can effectively track the changes of power line channel,obviously improve the normalized mean square error and bit error rate performance.