In this paper, we address the problem of power line communication inside a vehicle, focusing on channel characterization and modeling. The statistical properties of the transfer function between two points in the power distribution system are deduced from a propagation model that takes into account the complicated structure of the cable bundles. Theoretical estimates are compared to experimental results. Later on, this theoretical model, together with an impulsive noise model, will be implemented in a software communication tool that is designed to optimize modulation schemes and channel coding.

Modeling and Analysis of In-Vehicle Power Line Communication Channels

In-vehicle power line communication (PLC) holds great promises as an enabler of in-vehicle communication without increasing weight, volume, or cost of the wiring harnesses. In this paper, we join a few recent works and present channel measurements for a specific compact car. We discuss and compare our measurement results with those obtained in previous campaigns. Furthermore, we evaluate our measurements from the viewpoint of high connectivity. That is, we are interested in the suitability of PLC for applications that require a reliable link from any node to any other node at any time. Perhaps not surprisingly, we find that advanced transmission techniques such as multihop or frequency diversity are necessary to achieve this goal.

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Measurement study and transmission for in-vehicle power line communication

Impulsive noise can have a great influence on the performance of in-vehicle power line communication systems. Intensive noise measurements in the time domain were thus carried out on five different vehicles. Preliminary trials were first made on a stationary vehicle and the motor idling, but the characteristics of the measured low-amplitude pulses greatly vary from one car to another. We thus emphasize the characteristics of high-amplitude pulses, greater than 70 mV, observed when the vehicles were moving in traffic, during a 20-min trip. Noise is statistically characterized in terms of duration, frequency content, peak amplitude, and time interval between successive pulses. Stochastic models based on mathematical distribution functions and fitting the experimental distribution of the various pulse characteristics are proposed. It has been found that interarrival time, i.e., the time interval between two successive pulses, is rather short and would be thus the most critical parameter when optimizing the power line communication physical layer.

Impulsive Noise Characterization of In-Vehicle Power Line

This paper investigates the possibility of using the powerline communications (PLC) technology to transmit data along differential dc power buses employed in spacecraft. To this end, a point-to-point interconnection between the power control and distribution unit (PCDU) and a dc/dc converter is considered. The power bus is composed of a twisted-wire pair (TWP) above ground, and capacitive coupling and inductive decoupling networks are adopted. The analysis focuses on channel characterization and electromagnetic compatibility (EMC) assessment of a PLC link for low-speed interconnections with sensors. A transmission line model is adopted for the powerline (PL) involving measurement-based emission models for the power units connected to the line ends. Modal analysis is used to estimate the channel performance in terms of signal and noise transfer ratios. It is shown that use of a balanced transmission scheme assures higher performance both in terms of channel transfer function and immunity to the PL-conducted noise generated by dc/dc converters. A prototype of the PLC link, involving a specific implementation, is realized to prove feasibility and to analyze the system EMC behavior in terms of radiated emissions, conducted and radiated susceptibility.

Channel Characterization and EMC Assessment of a PLC System for Spacecraft DC Differential Power Buses

In this paper, immunity of differential dc power lines, recently considered as the physical layer for power line communications (PLC) onboard spacecraft, is assessed from the theoretical viewpoint. The analysis focuses on conducted immunity of the PLC channel to noise generated by the terminal units of the power line (PL). Particularly, multiconductor transmission line theory and modal decomposition are used to characterize the susceptibility of the PLC link to common mode and differential mode (DM) components of the conducted noise. Closed-form expressions for signal and noise contributions at the receiving modem are derived and used to develop design rules for the involved coupling/decoupling networks. By combining the spectral properties of the PL noise with the propagation properties of the link, it is shown that DM signaling, besides assuring a nearly flat channel frequency response, results to be more immune to the PL noise. Finally, the role that possible unbalance of the power units may play on the system conducted immunity and radiation properties is discussed by deriving analytical expressions of the longitudinal and transversal conversion loss associated with the PL terminal networks.

Immunity to Conducted Noise of Data Transmission Along DC Power Lines Involving Twisted-Wire Pairs Above Ground

This paper presents an investigation of the properties of vehicular DC-lines for the purpose of data communication. In doing so, the aim is to model the transfer channel that represents these lines. The basis for this investigation is established by measurements of battery lines in vehicles. First various line segments are regarded without disturbance. In a second step the existing interference is investigated. With particular interest the impulsive noise is regarded. Important is the possibility to calculate its random occurrence by a statistical process called Poisson process. The present results are the basis for further investigations of data communication over DC-lines in cars.

A. Schiffer

Papers

Statistical channel and noise modeling of vehicular DC-lines for data communication