Probabilité de la distance minimale pour un système MIMO précode

International audienceThis paper deals with precoded MIMO systems using channel state information. Such systems are now included in recent wireless norms. However, theoretical evaluations of performance are more complex. We propose a method based on the statistics of the minimal distance in order to evaluate the capcity or bit error rate (BER) in an uncorrelated Rayleigh fadding channel

Teaching protocol exchanges over cellular air interface

International audienceThe evolutionary path taken by cellular standards to the current and future standards is incomplete without fully understanding the older standards. The comprehension of the GSM standard, specifically the procedures for protocols exchange over the air interface will help students understand radio resource allocation procedures in GPRS and UMTS, and will ultimately assist future communication engineers to be able to design and solve problems related to these cellular standards. In this paper we describe the novel architecture of our teaching software, developed and programmed in Java. We present all the user interfaces and show how it can be used to assist in teaching, by presenting how the Mobile station and the GSM/GPRS network exchange data frames over the air interface with their associated protocols. Finally the uniqueness of this teaching tool was proved from the stand point of our modular architecture

Optimization of transmissions in wireless sensor networks by closed-loop cooperative MIMO in perturbed environment

Le système MIMO coopératif est une solution attrayante dans un environnement où les trajets multiples signalent s'avérer être une étape stimulante pour le lien paire communication émetteur-récepteur. En effet, la diversité spatiale fournis par les émetteurs et recievers peut être exploitée pour améliorer la qualité du signal. Cette thèse étudie l'application de la boucle fermée précodeur MIMO pour réduire encore plus l'énergie de transmission dans un tel environnement. La contribution de cette thèse est de proposer des approches globales qui conduisent à l'optimisation globale des transmissions dans le système MIMO coopératif. Tout d'abord, on exploite la diversité spatiale des noeuds, et proposons une technique de sélection de noeud pour réduire l'énergie de transmission. Les noeuds sont sélectionnées en utilisant le linéaire boucle fermée MIMO précodeur max-dmin qui optimise la distance minimale (dmin) de critère pour réduire le BER de la constellation reçue, ce qui abaisse le rapport requis signal sur bruit (SNR). Deuxièmement, nous sommes motivés par une obligation de rendre les paramètres d'évaluation des performances MIMO disponibles aux couches supérieures du protocole. Ainsi, nous proposons une méthode théorique pour obtenir la fonction de distribution de probabilité (pdf) de dmin pour le précodeur max-dmin, nous utilisons le résultat de rapprocher le BER et de la capacité ergodique pour un système MIMO et une valeur de M en utilisant deux sous-canaux dans d'une manière rapide. Nous présentons un scénario qui exige que l'information pertinente soit détectée à partir d'une variété de sources situées à l'intérieur de la haute tension (HT) environnement du poste de réseau intelligent (SG) des applications. Notre contribution comprend le développement d'un outil de simulation basé sur la technique de sélection de noeuds pour le max-dmin distribué MIMO précodage. Pour tenir compte des interactions entre les couches multiples de communication, nous proposons de concevoir un système de communication MIMO coopératif complet basé sur un protocole d'échange de base qui est liée à notre scénario de transmission supposé. On construit en outre toutes les trames de sous-couche MAC, qui sont transmis dans ce système limité par le coût de l'énergie et de la synchronisation.Cooperative MIMO system worked from the spatial diversity provided by the transmitters and receivers locations to improve the quality of service in the communication exchange. In our work, we explored the application of closed-loop MIMO precoder to further limit the energy of transmission in such environment. Our contribution is to propose approaches that lead to global optimization of transmissions in cooperative MIMO system. Firstly, we exploit spatial diversity of nodes, and then a node selection technique to reduce the energy of transmission. The nodes are selected using the max-dmin linear closed-loop MIMO precoder which, optimizes the minimum distance (dmin) criterion to reduce the Bit Error Rate of the received constellation, thereby lowering the required signal-to-noise ratio. Secondly, we are motivated by a requirement to make the MIMO performance evaluation parameters available to higher protocol layers. Thus, we propose a theoretical method to derive the probability distribution function of dmin for the max-dmin precoder, then we use the result to approximate the Bit Error Rate and ergodic capacity for any MIMO system and any value of modulation size M using 2 subchannels in a rapid manner. To achieve our objective, we present a realistic scenario from an existing application case where data must be collected from a variety of sources located inside a high voltage substation environment (smart grid applications). Our contribution involves the development of a simulation tool based on node selection technique for the max-dmin distributed MIMO precoding. Finally, inside this transmission scenario, we propose a complete communication system based on a basic exchange protocol. We further construct all the MAC sub layer frames that are transmitted in this system constrained by energy and synchronization cost

A learning tool for cellular air interfaces (GSM, GPRS, UMTS and WLAN).

M. Tech. Electrical Engineering.Describes the architecture of the VIGIE (Visualisation and Interpretation of GSM/GPRS for Institutes & Ecole) software, developed in Java to display the exchanges of these tasks between the MS (mobile station) and the network. The uniqueness in the architecture of this tool is revealed in terms of its modularity. Finally the current work done on the development of the General Packet Radio Service (GPRS) logical screen and the Downlink Signalling Counter (DSC) graphical screen are described

VIGIE : A learning tool for cellular air interfaces (GSM, GPRS, UMTS, WiFi)

International audienceOne of the difficulties encountered in the teaching of mobile radio networks is to present in a simple way the interaction and the sequencingof various tasks, which must be carried out by themobile station (MS) and the network over the airinterface. The comprehension of these processesis facilitated when they are presented in a visualform that can be understood in real-time, when thecommon MS-Network tasks such as voice call (MSoriented or MS terminated), short message service(SMS) are going on. This paper describes thearchitecture of the VIGIE (Visualisation andInterpretation of GSM/GPRS for Institutes & Ecole)software, developed in Java to display theexchanges of these tasks between the MS and thenetwork. The uniqueness in the architecture of this tool is revealed in terms of its modularity. Finally the current work done on the development of the General Packet Radio Service (GPRS) logicalscreen and the Downlink Signaling Counter (DSC)graphical screen are described

Cooperative Closed-loop MIMO Selective Transmissions in a HV Environment

International audience—Integrated communications with sensing and measurements are relevant technologies identified to pro-vide automation for the smart grid (SG) applications. Incorporating intelligence into the electrical grid neces-sitates the gathering of relevant information in in real-time from variety of electrical utility sources located either at the bulk generation, transmission, distribution or customer domain. The deployment of wireless sensor network (WSN) is an attractive solution for such task, due to certain merits. In this paper, we show how large WSN cluster could benefit from distributed max-dmin MIMO precoder with a proposed node selection technique offering a realistic implementation. We exploit spatial diversity of the nodes to make the channel state information (CSI) available at transmitting nodes organized into a cluster. Performance evaluation of the nodes selection technique shows substantial amount of energy can be saved in high voltage (HV) power substation channel environment that is corrupted by Additive White Gaussian Noise (AWGN), impulsive noise, and node synchronization errors

Performance Analysis of Closed-Loop MIMO Precoder Based on the Probability of Minimum Distance

International audienceLinear closed-loop MIMO precoders are attractive owing to their scalability. They can significantly improve the received signal via optimization of pertinent criterion. The solution of max-dmin precoding is optimal for 4-QAM as it utilizes the channel state information at the transmitter (CSIT) to minimize the system error probability making it very attractive. However, as M increases the solution which is dependent on channel angle gets complex, due to its multi-form precoder search. Motivated by a requirement to provide MIMO system evaluation parameters to upper layer protocol(s) as a function of precoder optimization criterion, we propose deriving a general expression for the probability density function (pdf) of max-dmin. Our approach applies numerical approximations to derive the system bit error rate (BER) and ergodic capacity for any values of M, nr, and nt, and with b = 2 data streams. Results show that the performance of our numerical approximation approach is close to the analytical simulation method

Cooperative Closed-loop Techniques for Optimized Transmission applied to a WSN in a Power Substation

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