An Adaptive Impedance-Matching System for Vehicular Power Line Communication

Vehicular power line communication (VPLC) is being considered as a potential solution to mitigate the increase of complexity and cost of the automotive wiring harness caused by the growth of the number of electronic devices and sensors deployed inside vehicles. This is because VPLC reuses power cables for data communication and, thus, avoids the need for additional communication wires. However, this reuse does not come without problems. One of the challenges for VPLC is the time, frequency, and location dependence of the access impedance, which can cause severe impedance mismatch for the communication signal. Impedance mismatch degrades the signal-to-noise-power ratio at the communication receiver and thus affects transmission reliability. Due to the variable nature of the access impedance, a fixed matching circuit will be inefficient. Hence, in this work, we present an adaptive impedance-matching system, which improves the communication-signal transfer from the transmitting to the receiving device. The system is evaluated via simulations for a wide range of access-impedance test points and $S$- parameters of VPLC networks obtained in previous measurement campaigns. Our simulation results demonstrate that the presented adaptive matching system is able to achieve VPLC signal-power transfer within 30% of the theoretical optimum. This translates to a power gain, up to a factor of 10, which is larger than that of other solutions reported in the literature.