基于QoS策略的低压电力线信道容量研究

Study of channel capacity for low power-line based on QoS strategy

为了在有限的传输带宽内使低压电力线信道容量最大化,提出了基于特定QoS策略的约束注水算法。该算法以低压电力线信道多径传输模型为研究基础,从信号功率受限的角度出发,导出了信道容量最大化的闭式解,分析并得出信道分支支路数和终端负载阻抗是影响信道容量的主要因素。利用正交频分复用(OFDM)技术对输入信号进行离散化调制,得到了不同信道状况下的最大传输比特数。仿真结果表明,所提算法的信道容量优于已有注水法,在信噪比为40dB时,所提算法的最大容量为经典注水法的1.37倍,完全满足低压电力线高速载波通信的要求。

In order to maximize the low power-line channel capacity under the constraints of bandwidth, a method of water-filling algorithm based on the specific QoS strategy is proposed. The multipath propagation model is used to derive the closed-expression of the maximum channel capacity under the condition of power limit. The analytic results show that the number of branches, the length of branches and different terminal loads have effects on the PLC channel capacity. Simulation results show that the mainly factors that affect the channel capacity of indoor low power-line are branch number and load impendence. In order to evaluate the performance of the proposed algorithm, a simulation environment based on OFDM is designed. The simulation results show that at the same SNR, the performance of proposed algorithm is superior to the existed water-filling algorithms. When SNR=40dB, the maximum capacity of the proposed algorithm is 1.37 times more than that of the classical water-filling algorithm, thus meeting the demand of high speed index in low power-line carrier communication system.