Throughput optimization based on access impedance of PLC modems with limited power consumption

Power line Communication (PLC) plays a key role to establish the future smart grids. However, the power line channel has greatly changeable characteristics that must be considered, namely the access impedance, the transfer function and the noise in the low frequency range. The access impedance of the power line channel is frequency, time and from cable to cable variant. This problem is the main reason of reducing the transferred power, the channel capacity and the communication range as well. PLC transmitting modems have limited power consumption because of the new energy efficiency rules. Today this requirement is implemented with a scaling of the complete signal to fulfill the current limitation. In this paper we present the influence of the power line access impedance on the PLC transmission systems considering the channel capacity as a system performance. We take PRIME technology as an example and simulate it to find its channel capacity considering access impedance values related to EN50056-1 standard and compare it to real access impedance measurement values. Furthermore, the paper introduces two channel capacity optimization methods: The new algorithm by switching off some subcarriers and the iterative algorithm by optimizing the amplitude of each subcarrier on the bandwidth. The state of the art and the two optimization methods are shown in the simulation results.