Mohamed Cheikh

Transmission quality evaluation of Tire Pressure Monitoring Systems

Many papers dealing with the TPMS (Tire Pressure Monitoring System) communication mechanisms between sensors (transmitters) and receiver have been published, but most of the work has been focused on the particular effects of the radiofrequency channel [1], the antenna design [2], the communication protocol or the mechanical housing. The full transmission context analysis lacks to the understanding of the observed phenomena, in particular the effects of propagation channel on dynamic reception quality for TPMS. In this study, we propose a step by step analysis by evaluating the influence of each element contributing to the overall performance of the communication process. In the first section, an original space sounding is developed to characterize the radiofrequency channel variation. The second part presents simulations in order to improve the burst reception efficiency: the protocol is investigated versus different channel profiles in order to reduce the rate of lost frames.

Power source evaluation of a wireless power transfer system

With more than 230 products on store shelves and an estimation of 100 million wireless power devices in use by 2015 (IHS source), the wireless power market is rapidly growing. Moreover, current smartphones are used with several applications (music streaming, satellite navigation system or even NFC virtual key for car sharing) and thus a convenient power supply system is required. This paper addresses the complete modeling and characterization of this power source in a Wireless Power Transfer context by an original modeling approach. A good correlation between measurement and simulation is obtained both for electrical (e.g. input impedance, power, etc.) and electromagnetic (e.g. magnetic field) quantities. Through simulations performed on commercial softwares, the correlation simulation/measurement shows a difference of only 2% on the active power available on the load and the modeled behavior of the magnetic field corroborates with the measured one.

Efficient Time Diversity Evaluation for Direct Tire Pressure Monitoring System

As a step into the new generation of direct Tire Pressure Monitoring Systems (TPMS), a major concern is to increase the performance of the radio frequency communication between the intelligent tires and the receiver. The purpose of this paper is to propose an original analysis of the time diversity gain as a promising way of improving the performance of wireless TPMS communication. The goal is to quantify the time diversity improvement provided with the analysis of the relationship between the reception probability, the vehicle speed and the radio propagation channel on which diversity efficiency depends. This is achieved through a powerful method for evaluating the improvement from real channels measurements.

An Empirical Study of RF Link for Wireless Automotive Passive Entry System

The wireless systems in automotive applications increase for security and comfort considerations. As the structure of the car involves many metallic frames, the channel of the RF signal is tricky to model. As a consequence,the developers need efficient and accurate means of characterization to develop these systems. This study proposes a full characterization of a RF link between a transmitter (badge) and a receiver (integrated in the structure of the car). As the design of a car is relevant with a multi-scale analysis, the needs can vary from a car to another one: we propose a strategy based on the development of generic wireless modules to cut the development costs. Therefore, the medium of propagation influence is intensively characterized to develop matched strategies for secured data propagation. First, an empirical analysis describes on the radio channel characterization for the car access systems. Then, the received field is measured in 2D around the vehicle for different various parameters (vehicle frame, antennas relative heights, badge and receivers position and relative distance). The free radio frequency of 434 MHz is chosen for this study.

Design and simulation of printed winding inductors for inductive wireless power charging applications

Winding coils are key elements in the design and the implementation of an effective wireless power charging platform for wireless devices such as mobile phones, smart phones and tablet computers. Planar winding inductors are low-cost, ready to integrate with the electronics and fully compatible with a general printed circuit board (PCB) manufacturing process. This paper addresses the design and the simulation of the planar winding inductors in order to overcome some drawbacks of such structures concerning mainly the quality factor and the resistive/thermal losses.