Physical Layer Performance Analysis of Power Line Communication (PLC) applied for Cell-Wise Monitoring of Automotive Lithium-Ion Batteries

State of the art battery management systems for automotive applications require a large number of cables for the wiring harness. Our research work focuses on employing the battery power line for communication purposes to reduce the wiring overhead and the incurring product costs. Since power lines represent a particularly difficult communication environment with respect to channel transfer and noise characteristics, a thorough understanding of the channel is required to design and implement the physical layer. The paper addresses a comparison of single and multi-carrier modulation techniques in the specific context of power line communication (PLC) for automotive battery systems based on Lithium-Ion technology. Our channel modeling approach is based on the channel characteristics, which in general may be time- and frequency-dependent, and also dependent on the location of transmitter and receiver in the specific battery power line network. We describe the channel by the measurement-based transfer function and a random time varying Additive White Gaussian Noise (AWGN). Our investigations focus on the robustness of the PLC system to intersymbol interference (ISI). We focus on transmission frequencies above 10 MHz and investigate the performance of single and multi carrier modulation schemes for high data rates (>5 Mbit/s). It will be shown that Orthogonal Frequency Division Multiplexing (OFDM) does not offer advantages over single carrier modulation schemes with convolutional channel coding for Eb=N0 <10 dB, even though no equalization is applied for single carrier transmission. In case Eb=N0 >10 dB, OFDM systems achieve a better performance than single carrier systems in terms of bit error rate (BER).