G. El Zein

Low power microwave systems for heartbeat rate detection at 2.4, 5.8, 10 and 16 GHz

This paper demonstrates the possibility of detecting heartbeats using a vector network analyzer and two antennas. Within the same system, a comparative study is performed by using different frequencies with different power levels for each frequency. In an anechoic chamber, measurements were taken at 2.4, 5.8, 10 and 16 GHz. This work proves the ability to accurately detect heart activity and extract heartbeat rates, using low power such as -30 dBm from the radiating structure.

Time domain measurements for a time reversal SIMO system in reverberation chamber and in an indoor environment

Time domain measurements are conducted for ultra-wideband (UWB) signals in a reverberation chamber (RC) and in a typical indoor environment for a single input multiple output (SIMO) time reversal (TR) system. Channel estimation is carried out using an Arbitrary Waveform Generator (AWG) and a high speed Digital Storage Oscilloscope (DSO) for all transmitter receiver links. The measured channel impulse responses (CIR) of all the links are added and re-transmitted from the transmitting antenna. Upon reaching the receiving antennas, the received signals are added to form the eventual received signal. Different TR characteristics i.e. TR peak performance, TR focusing gain, average power increase, signal to side lobe ratio (SSR) and RMS delay spread are analyzed and compared to that of a single input single output (SISO) TR system.

Cooperative communications between vehicles and intelligent road signs

CAPTIV is a research program proposing new low-cost and energy-efficient mobile communications solutions to ease and make safer road traffic conditions. Considering ¿intelligent¿ road signs and vehicles, i.e. equipped with an autonomous radio communication system, drivers will be able to receive at any time various information about traffic fluidity or road sign identification. In order to reduce deployment cost and increase lifetime of the whole system, Multi-Input Multi-Output (MIMO) signal processing techniques are used. Considering each crossroads as a communication node, the possible cooperation between road signs allows energy-efficient communications between crossroads. MIMO channels characterization and modeling, specific antennas conception, associated with signal processing techniques allow to further optimize the energy consumption between nodes. A driving simulator is used in order to both validate the communication system and protocols between vehicles and road signs and evaluate the effect of the additional information on the driver behavior. Supported by the Brittany Regional Council, CAPTIV is a highly applicative program. A first prototype of such a communicating crossroads will be presented in the Vehipole in Saint-Brieuc (technological site devoted to ITS experimentations).

A Tunable System for Contact-Less Heartbeat Detection and a Modeling Approach

The aim of this work is to present a practical study to detect heartbeats from distance, as well as cardiopulmonary activity modeling and simulation, in order to separate the heart and the respiration signals. Using a Vector Network Analyzer, measurements are taken at 2.4, 5.8, 10,16 and 60 GHz. The Matlab simulation permits comparing several signal processing techniques in order to identify the most accurate one.

Wideband measurements and analysis of propagation losses within a building

A simplified setup using an HP network analyzer to perform path loss measurements for the indoor radio channel in the 0.8-1.0 GHz band is described. In order to analyze the frequency selectivity of the channel, two data postprocessing methods are proposed. A comparison with another published method is also presented.<<ETX>>

Indoor MIMO channel sounding at 3.5 GHz

This paper presents a measurement campaign carried out at 3.5 GHz. The objective is to characterize the electromagnetic waves propagation in indoor environment. A double directional channel sounder was used to perform these measurements. The collected data were then processed with a high resolution algorithm to extract the multipath parameters. A comparison between measurement results and a ray tracing tool is done to interpret the propagation mechanisms in this environment. The aim of these measurement campaigns is to obtain realistic MIMO channel models.

Electromagnetic propagation modeling in office environment

Wireless propagation modeling is more and more needed for optimal indoor coverage in complex environment (such as offices, classrooms, etc.). Thus the need to predict electromagnetic propagation efficiently and accurately in the presence of obstacles, allowing engineers to planning efficiently the communicating devices. This paper will present a rigorous electromagnetic indoor propagation modeling based on the FDTD (3D) method taking into account the presence of various obstacles. A comparison between numerical results obtained by FDTD code and Ray Tracing software will be presented and compared with measurement results. Computational performance efficiency of these methods will also be discussed.

Hardware simulator design for LTE applications with time-varying MIMO channels

A hardware simulator facilitates the test and validation cycles by replicating channel artifacts in a controllable and repeatable laboratory environment. This paper presents new frequency domain and time domain architectures of the digital block of a hardware simulator of MIMO propagation channels. The two architectures are tested with LTE standard, in outdoor environment, using time-varying channels. The new architectures of the digital block are presented and designed on a Xilinx Virtex-IV FPGA. Their accuracy and latency are analyzed. The result shows that the architectures produce low occupation on the FPGA and have a small relative error of the output signals.

Antenna Arrays Design and Calibration for 4×4 Mobile MIMO Channel Sounding at 3.5 GHZ

The use of antenna arrays at emission and reception is an attractive solution for future wireless systems in order to improve data rates and quality of service. The performance of these systems is very dependent on propagation channel. In this context, channel characterization and modeling are crucial. In this paper, we present the design and calibration of two antenna arrays for high resolution MIMO channel sounding at 3.5 GHz. This frequency band concerns wireless local loop applications. The beam patterns of these arrays are measured in anechoic chamber. A calibration algorithm is applied on these beam patterns to obtain better multi-path parameters estimation. The results obtained after applying the calibration algorithm are presented. Moreover, simulation results clearly show the calibration effect on multi-path parameter estimation.

Antenna Arrays Design and Calibration for 4×4 Mobile Radio Channels Measurements at 3.5 GHz

In this paper, we present the design and calibration of two antenna arrays, of 4 active elements each, at 3.5 GHz for double directional channel measurements. This frequency band is used for wireless local loop (WLL) applications. The beam patterns of these two arrays are measured in anechoic chamber. A calibration algorithm is applied on these measurements for high resolution 4times4 MIMO (multiple input multiple output) channel sounding. Results obtained after the beam patterns calibration are presented. The importance of this work is shown by ESPRIT simulations for better multipath parameters estimation.