Pierre Laly

Impulsive Noise Characterization of In-Vehicle Power Line

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.

Performances of the HomePlug PHY layer in the context of in-vehicle powerline communications

The feasibility of an in-vehicle PLC, based on HomePlug standards is studied. The channel characteristics introduced in the simulation software are those deduced both from transfer function and noise measurement and from propagation modelling.

Impulsive Noise on In-Vehicle Power Lines: Characterization and Impact on Communication Performance

This paper deals with the characterization of impulsive noise on in-vehicle power lines and the impact of this noise on communication performance. After briefly presenting the communication system, the principle of noise measurement is described and a statistical analysis of impulsive noise is carried out. A noise model is proposed and is then used in communication software, simulating the link, for determining the system performance in terms of erroneous bits or frame errors. The chosen communication standard is the one proposed by the HomePlug 1.0 for PLC indoor communication

Long-range radar sensor for application in railway tunnels

This paper presents a feasibility study of a technique for measuring the distance between two trains following one another through a tunnel at a distance of several kilometers. A preliminary series of measurements was performed in the Channel Tunnel, between France and England, in order to characterize the propagation of high-frequency waves in such an environment, with the primary objective of showing the influence of frequency on received power. After a description of the main results of this first phase, a measurement system based on correlation techniques and employing pseudorandom sequences is presented. The last section of this paper reports the test results produced by the prototype; these results show promise in terms of range and measurement accuracy.

Performance Analysis of Antenna Arrays in Tunnel Environment

Previous works have shown that multiple-input-multiple-output techniques such as space-time block code applied to tunnel environments present better performances than a single-input-single-output transmission, despite the small angular spread of the rays in this environment. Nevertheless, taking the guiding effect of the tunnel into account, one can wonder whether the simplest diversity schemes, in terms of complexity and implementation, may be a challenging solution, at least if compact arrays are used. The objective of this letter is thus to compare the performances of transmission schemes using diversity either at both ends of the link or at only the receiving side. The determination of symbol error rate is based on Monte Carlo simulations using channel matrices measured in a straight arched tunnel.

Polarization Properties of Specular and Dense Multipath Components in a Large Industrial Hall

This paper presents a comprehensive analysis of the polarization characteristics of specular and dense multipath components (SMC and DMC) in a large industrial hall based on frequency-domain channel sounding experiments at 1.3 GHz with 22-MHz bandwidth. Twenty-nine positions were measured under line-of-sight (LOS) and obstructed LOS (OLOS) scenarios. The RiMAX maximum-likelihood estimator is used to extract the full-polarimetric SMC and DMC from the measurement data by taking into account the polarimetric radiating patterns of the dual-polarized antennas. Cross-polar discrimination (XPD) and copolar ratio (CPR) values are presented from the measured and de-embedded channels, as well as the polarimetric delay and angular spread distributions. Strong de-embedded SMC depolarization is obtained for the horizontal polarization in OLOS scenarios. Additionally, DMC depolarization is observed to be weaker than previously reported for indoor environments but constant across LOS/OLOS, polarization, and distance. The results also show that the copolar (cross-polar) DMC power to total channel power ratio is equal to 15% (40%) for LOS and 40% (60%) for OLOS and that this ratio does not correlate significantly with transmitter-receiver distance. Finally, the validity of the room electromagnetics theory was confirmed for transmitter-receiver distances larger than 15 m with no significant difference between polarized subchannels.

Transmission on aircraft power line between an inverter and a motor: Impulsive noise characterization

Data transmission between an inverter and a motor is usually ensured through dedicated cables. However, for many applications and especially in aircraft, the weight of the wiring is becoming critical. One possible technique to decrease the number of wires is to implement a power line communication (PLC) on the 3-phase power cable connecting the inverter and the motor. The objective of this paper is first to present experimental results on noise measurements, both in the frequency and in the time domain. Secondly, a software tool has been built to simulate a PLC communication based on the HomePlugAV specifications or on the OPERA specifications. A parametric study was performed to outline the influence of the impulsive noise on the link performances.

Investigation on power line communication in aircrafts

Power line communication is envisaged for the future more electric aircraft and the scenario studied in this work deals with the cabin lighting system, since its tree-shaped architecture is sufficiently complicated to be representative of many other aircraft harness configurations. The statistical characteristics of the propagation channels are deduced from the measurements made on a representative test bench, the experimental values of the insertion gain being also compared with those obtained from a theoretical model based on the multiconductor transmission line theory. Field-programmable gate array-based modems have been designed and the performance of links are described and compared with predicted values deduced from a software tool simulating the link.

Impulsive noise generated by a pulse width modulation inverter: Modeling and impact on powerline communication

Currently, to ensure data transmission between an inverter and the sensors implemented on a motor, a dedicated cable is used. Since in an aircraft environment, weight is a critical issue, this cable may be avoided by using Power Line Communication technology (PLC), i.e. by transmitting the information on the 3-phase power cable connecting the inverter and the motor. This approach also presents advantages in terms of reliability and maintenance. However impulsive noise due to the inverter has a strong impact on the performances of the link. In order to optimize the communication scheme, it is important to characterize this noise both in the frequency domain and in the time domain. The objective of the work presented in this paper is first to extract the main impulsive noise characteristics and to study their variation as a function of the electrical configuration as the rotation speed of the motor. A noise model is then proposed to be used as an input in a software tool simulating the link in order to optimize the transmission scheme. Performances of PLC links are calculated in terms of bit error rate for different bit rates.

Power line communication between an inverter and a motor: Noise characterization in the time domain and in the frequency domain

Power Line Communication may be used to transmit information from the sensors distributed on a motor to the electronic command of the converter feeding this motor. The interest of using the three phase cable as a physical support for the transmission is that the additional line dedicated for data can be avoided. However, impulsive noise generated by the converter is of large amplitude and covers a wide frequency band. The main objective of this paper is to characterize and analyze this noise both in the time domain and in the frequency domain. Three different configurations of Inverter/Motor with different power supplies and switching frequencies are studied, and a comparison is carried out in terms of noise characteristic parameters as amplitude, frequency content, duration, and time interval between pulses. Lastly, the impact of such pulses on a high bit rate communication is outlined.