Hanna Farhat

A Dual Band MIMO Channel Sounder at 2.2 and 3.5 GHz

The use of antenna arrays for the future wireless systems is a good solution to increase data rates and quality of service. The performances of these systems are very dependent on the propagation channel between the transmitter and receiver sites. That makes the spatio-temporal characterization and modeling of the channel very crucial in this context. In this paper, we present a wideband MIMO (multiple-input multiple-output) channel sounder at 2.2 and 3.5 GHz. It allows measuring the double directional properties of the propagation channel at emission and reception. Different architectures of antenna arrays are presented. The two high resolution algorithms unitary ESPRIT and SAGE are applied on measurement data to obtain more resolution and accuracy. Beam patterns measurement results for antenna arrays calibration in anechoic chamber are presented. Finally, some propagation measurement results are illustrated.

Characterization and modeling of the MIMO propagation channel: an overview

This paper deals with several aspects relative to the multiple-input multiple-output (MIMO) propagation channel. Different approaches used to model the MIMO channel are first presented. Then, the different measurement techniques used in order to characterize the propagation channel are described. Measurement campaigns made in urban environments have been analyzed to obtain the relevant statistical parameters of the channel. These results make it possible to discuss the integration of MIMO techniques in practical wireless communication systems

Performance analysis of a hierarchical shipboard Wireless Sensor Network

Wireless Sensor Networks (WSN) have recently gained a great attention in several applications such as environmental monitoring and target tracking. Applying this technology to shipboard monitoring systems may be a cost-effective solution to reduce the cost of wires installation and maintenance. However, wireless communications on board ships may be severely obstructed by the metallic structure of bulkheads. In this paper, we analyze the efficiency of a shipboard WSN by measurement and simulation. A measurement campaign is conducted to study the radio wave propagation and to verify the feasibility of a WSN on board a ship. Based on the measurement results, a hierarchical group-based topology for a large-scale shipboard WSN is proposed. A realistic simulation model of the ship, taking into account the environment particularities, is then performed using OPNET network simulator. Performance of the WSN architecture is evaluated using the ZigBee model. Measurement results show the feasibility of WSN technology on board ships, while simulation results show significant performance of proposed architecture in terms of end-to-end delay and packet delivery ratio.

Wireless Sensor Network on board vessels

Wireless Sensor Networks (WSNs) have been used recently in different applications such as environmental monitoring and target tracking. Few papers have investigated the viability of this technology on board ships. We study in this paper the possibility of replacing the wired shipboard monitoring system by a WSN. This environment has a specific metallic structure which makes the wireless communication more difficult than in other classical indoor and outdoor environments. Two types of experiments have been carried out on board a ferry-type boat during sailings and stopovers. The first experiment consists of point-to-point measurements using ZigBee-based equipments and the second one consists of deploying and testing a WSN on board the ferry. These tests have been conducted during realistic conditions on board the ferry, which give a high level of reliability to results with respect to the earlier experiments on board ships moored to the harbor. In spite of the harsh metallic structure and the dynamic environments on board the ferry, the obtained results have shown that the wireless solution may be a cost-effective alternative to the huge amount of cables used currently to connect sensors to central control units.

MIMO Channel Sounder at 3.5 GHz: Application to WiMAX System

The use of antenna arrays at emission and reception seems to represent a prominent solution for future wireless systems, it improves data rates and enhances the quality of service. The performance of these systems depends mainly on the propagation channel. Therefore, channel’s characterization and modeling are crucial. In this document, we present a MIMO (Multiple Input Multiple Output) channel sounder at 3.5 GHz developed at IETR. One of the applications operating at this frequency is the WiMAX system. Different antenna arrays architectures are designed and calibrated at 3.5 GHz for high resolution MIMO channel sounding. Antenna arrays beam patterns are measured and calibrated. The importance of this work is shown by ESPRIT simulations. Propagation measurement results are needed to obtain realistic MIMO channel models.

Hardware Simulator Design for MIMO Propagation Channel on Shipboard at 2.2 GHz

A wireless communication system can be tested either in actual conditions or with a hardware simulator reproducing actual conditions. With a hardware simulator it is possible to freely simulate a desired radio channel, making it possible to test “on table” mobile radio equipments. This paper presents new architectures for the digital block of a hardware simulator of MIMO propagation channels. This simulator can be used for LTE and WLAN IEEE 802.11ac applications, in indoor and outdoor environments. However, in this paper, specific architectures of the digital block of the simulator for shipboard environment are presented. A hardware simulator must reproduce the behavior of the radio propagation channel. Thus, a measurements campaign has been conducted to obtain the impulse responses of the shipboard channel using a channel sounder designed and realized at IETR. After the presentation of the channel sounder, the channel impulse responses are described and implemented. Then, the new architectures of the digital block of the hardware simulator, implemented on a Xilinx Virtex-IV FPGA are presented. The accuracy, the occupation on the FPGA and the latency of the architectures are analyzed.

Application of Wireless Sensor Network for the Monitoring Systems of Vessels

This chapter studies the feasibility of WSN on board ships. Several measurement campaigns are conducted on board a ferry-boat to verify the possibility of wireless communications between ship parts and to analyse the performance of WSN on board. These measurements aim at determining path loss models for typical shipboard environments and testing the possibility of wireless communication between adjacent rooms or adjacent decks. Using the results of these experiments, a WSN is tested on board the ferry. The results obtained from the measurement campaigns are then used to propose an architecture for a large-scale shipboard WSN. As the network test uses a limited number of nodes, the full monitoring system based on the proposed architecture is simulated using a network simulator.

An infrared thermal image acquisition system for intra-vehicle applications

In this paper, we present an infrared thermal image acquisition system developed for intra-vehicle applications. This system is based on an uncooled microbolometer sensor matrix. First, we design an electronic board to control the sensor. A special lens is developed with a wide field of view. Then, the image acquisition system is developed on a FPGA (Field-Programmable Gate Array) based soft-core microcontroller. We realize the system calibration using controlled temperature surface. We implement the calibration algorithm and present calibration results. Measurement campaign is conducted in a vehicle. Measurement results show the possibility to cover all the passengers in the vehicle and to measure their temperature.

Positioning information based technique in cooperative MIMO-OFDM systems

Future Communication networks are tending towards a diverse wireless networking world where the positioning information (PI) could be helpful in different techniques like the dynamic resource allocation. On the other hand, the PI could be widely used for cooperative techniques in the relay and/or routing selection process. In this paper, we propose to use the PI in the selection of the relays and then to apply an efficient double layer distributed space time block code (DLSTBC) scheme between the different relays. Using the amplify and forward (AF) technique, we show that the proposed code is very efficient whatever the transmitted power is. Moreover, we show that the relay selection process based on PI yields very powerful results when compared to the random relay selection (RS) process.

Analysis of measured outdoor-to-indoor MIMO channel matrix at 3.5 GHz

Multiple antenna systems at the transmission and at the reception are commonly accepted in the standards of wireless systems (3GPP, IEEE802). However, it remains difficult to anticipate and to predict the real performances that can be achieved by these systems on the field. The problem becomes even trickier when considering challenging channels such as in outdoor-to-indoor conditions. The first step consists in analyzing the classical parameters of the propagation channel (attenuation, spreads of delays and angles). We propose in this paper to go beyond those investigations in analyzing the MIMO performances related to the analysis of the channel matrix H.