低压电力线通信(PLC)信道具有异常丰富的脉冲噪声,因而呈现出有限记忆性,亦即Markov性。分析了PLC信道脉冲噪声特点后,提出利用分群Markov链对PLC通信信道建模。根据信道脉冲噪声所具有的特点,建立合理假设,给出了分群Markov链的无误串分布公式:明确了由无误串分布确定基本转移概率矩阵的条件以及对应的模型;给出了基于非线性拟合方法的转移概率表达式。论文还对FSK,DPSK,QPSK以及8PSK调制方式下的PLC信道的无误串分布进行了实际测量,并利用所分群Markov链确定了Markov模型基本转移矩阵。对基本转移矩阵的分析表明,8PSK的性能最优,其结论与已有的结论完全吻合,从侧面佐证了信道Markov模型的有效性。
Based on the nature of impulse noise in the lower voltage power line communications (LV PLC) channels, LV PLC channels are supposed to be memory channels, that is Markov nature. In the paper, the characteristics of LV PLC channels are analyzed in detail and a partitioned Markov chain is proposed to model the channels. According to the LV PLC channels, some hypothesis are suggested, which lead to the derivation of the error-free distribution. By employing the Hamilton theorem, the elements in the basic transition matrix P could be solved with the nonlinear fitting method and the conditions for the general solution are given too. With the proposed model, channel properties with signal modulated by FSK, DPSK, QPSK and 8PSK are investigated. At the same time, the basic transition matrix is determined by the proposed method. After the transition matrix is analyzed, the conclusion that 8PSK is the best modulation scheme can be arrived, which is of good agreement with the published paper. This conclusion can verify that the proposed Markov model and the solution of the Markov parameters are correct.