In a 5 Generation massive Multiple Input Multiple Output radio network, the Channel State Information is playing a central role in the algorithm design and system evaluation. However, Acquisition of Channel State Information consumes system resources (e.g. time, frequency) which in turn decrease the link utilization, i.e. fewer resources left for actual data transmission. This problem is more apparent in a scenario when User Equipment terminals have multi-antennas and it would be beneficial to obtain Channel State Information between Base Station and different User Equipment antennas e.g. for purpose of high rank (number of streams) transmission towards this User Equipment. Typically, in current industrial implementations, in order to not waste system resources, Channel State Information is obtained for only one of the User Equipment antennas which then limits the downlink transmission rank to 1. Hence, we purpose a method based on Deep learning technique. In this paper, multi-layer perception and convolutional neural network are implemented. Data are generated by MATLAB simulator using the parameters provided by Huawei Technologies Co., Ltd. Finally, the model proposed by this project provides the best performance compared to the baseline algorithms. / I ett 5-generationsmassivt massivt multipel-inmatningsradio-nätverk spelar kanalstatens information en central roll i algoritmdesignen och systemutvärderingen. Förvärv av Channel State Information konsumerar emellertid systemresurser (t.ex. tid, frekvens) som i sin tur minskar länkanvändningen, dvs färre resurser kvar för faktisk dataöverföring. Detta problem är mer uppenbart i ett scenario när användarutrustningsterminaler har flera antenner och det skulle vara fördelaktigt att erhålla kanalstatusinformation mellan basstationen och olika användarutrustningsantenner, t.ex. för överföring av hög rang (antal strömmar) till denna användarutrustning. I nuvarande industriella implementeringar erhålls kanalstatusinformation för endast en av användarutrustningens antenner för att inte slösa bort systemresurser, vilket sedan begränsar överföringsrankningen för nedlänkning till 1. Därför syftar vi på en metod baserad på Deep learning-teknik. I detta dokument implementeras flerskiktsuppfattning och inblandat neuralt nätverk. Data genereras av MATLAB-simulator med hjälp av parametrarna som tillhandahålls av Huawei Technologies Co., Ltd. Slutligen ger modellen som föreslås av detta projekt bästa prestanda jämfört med baslinjealgoritmerna.

Laboratoire I3S/CNRS / Os sistemas de telecomunicaÃÃes atuais oferecem servios que demandam taxas de transmissÃo muito elevadas. O problema da identificaÃÃo de canal aparece nesse contexto com um problema da maior importÃncia. O uso de tÃcnicas cegas tem sido de grande interesse na busca por um melhor compromisso entre uma taxas binÃria adequada e a qualidade da informaÃÃo recuperada. Apoiando-se em propriedades especiais dos cumulantes de 4a ordem dos sinais à saÃda do canal, esta tese introduz novas ferramentas de processamento de sinais com aplicaÃÃes em sistemas de comunicaÃÃo rÃdio-mÃveis. Explorando a estrutura simÃtrica dos cumulantes de saÃda, o problema da identificaÃÃo cega de canais à abordado a partir de um modelo multilinear do tensor de cumulantes 4a ordem, baseado em uma decomposiÃÃo em fatores paralelos (Parafac). No caso SISO, os componentes do novo modelo tensorial apresentam uma estrutura Hankel. No caso de canais MIMO sem memÃria, a redundÃncia dos fatores tensoriais à explorada na estimaÃÃo dos coeficientes dos canal. Neste contexto, novos algoritmos de identificaÃÃo cega de canais sÃo desenvolvidos nesta tese com base em um problema de otimizaÃÃo de mÃnimos quadrados de passo Ãnico (SS-LS). Os mÃtodos propostos exploram plenamente a estrutura multilinear do tensor de cumulantes bem como suas simetrias e redundÃncias, evitando assim qualquer forma de prÃ-processamento. Com efeito, a abordagem SS-LS induz uma soluÃÃo baseada em um Ãnico procedimento de minimizaÃÃo, sem etapas intermediÃrias, contrariamente ao que ocorre na maior parte dos mÃtodos existentes na literatura. Utilizando apenas os cumulantes de ordem 4 e explorando o conceito de Arranjo Virtual, trata-se tambÃm o problema da localizaÃÃo de fontes, num contexto multiusuÃrio. Uma contribuÃÃo original consiste em aumentar o nÃmero de sensores virtuais com base em uma decomposiÃÃo particular do tensor de cumulantes, melhorando assim a resoluÃÃo do arranjo, cuja estrutura à tipicamente obtida quando se usa estatÃsticas de ordem 6. Considera-se ainda a estimaÃÃo dos parÃmetros fÃsicos de um canal de comunicaÃÃo MIMO com muti-percursos. AtravÃs de uma abordagem completamente cega, o canal multi-percurso à primeiramente tratado como um modelo convolutivo e uma nova tÃcnica à proposta para estimar seus coeficientes. Esta tÃcnica nÃo-paramÃtrica generaliza os mÃtodos previamente propostos para os casos SISO e MIMO (sem memÃria). Fazendo uso de um formalismo tensorial para representar o canal de multi-percursos MIMO, seus parÃmetros fÃsicos podem ser obtidos atravÃs de uma tÃcnica combinada de tipo ALS-MUSIC, baseada em um algoritmo de subespaÃo. Por fim, serà considerado o problema da determinaÃÃo de ordem de canais FIR, particularmente no caso de sistemas MISO. Um procedimento completo à introduzido para a detecÃÃo e estimaÃÃo de canais de comunicaÃÃo MISO seletivos em freqÃÃncia. O novo algoritmo, baseado em uma abordagem de deflaÃÃo, detecta sucessivamente cada fonte de sinal, determina a ordem de seu canal de transmissÃo individual e estima os coeficientes associados. / Les systÃmes de tÃlÃcommunications modernes exigent des dÃbits de transmission trÃs ÃlevÃs. Dans ce cadre, le problÃme dâidentification de canaux est un enjeu majeur. Lâutilisation de techniques aveugles est dâun grand intÃrÃt pour avoir le meilleur compromis entre un taux binaire adÃquat et la qualità de lâinformation rÃcupÃrÃe. En utilisant les propriÃtÃs des cumulants dâordre 4 des signaux de sortie du canal, cette thÃse introduit de nouvelles mÃthodes de traitement du signal tensoriel avec des applications pour les systÃmes de communication radio-mobiles. En utilisant la structure symÃtrique des cumulants de sortie, nous traitons le problÃme de lâidentification aveugle de canaux en introduisant un mod`ele multilinÃaire pour le tenseur des cumulants dâordre 4, basà sur une dÃcomposition de type Parafac. Dans le cas SISO, les composantes du modÃle tensoriel ont une structure de Hankel. Dans le cas de canaux MIMO instantanÃs, la redondance des facteurs tensoriels est exploitÃe pour lâestimation des coefficients du canal. Dans ce contexte, nous dÃveloppons des algorithmes dâidentification aveugle basÃs sur une minimisation de type moindres carrÃs à pas unique (SS-LS). Les mÃthodes proposÃes exploitent la structure multilinÃaire du tenseur de cumulants aussi bien que les relations de symÃtrie et de redondance, ce qui permet dâÃviter toute sorte de traitement au prÃalable. En effet, lâapproche SS-LS induit une solution basÃe sur une seule et unique procÃdure dâoptimisation, sans les Ãtapes intermÃdiaires requises par la majorità des mÃthodes existant dans la littÃrature. En exploitant seulement les cumulants dâordre 4 et le concept de rÃseau virtuel, nous abordons aussi le problÃme de la localisation de sources dans le cadre dâun rÃseau dâantennes multiutilisateur. Une contribution originale consiste à augmenter le nombre de capteurs virtuels en exploitant un arrangement particulier du tenseur de cumulants, de maniÃre à amÃliorer la rÃsolution du rÃseau, dont la structure Ãquivaut à celle qui est typiquement issue de lâutilisation des statistiques dâordre 6. Nous traitons par ailleurs le problÃme de lâestimation des paramÃtres physiques dâun canal de communication de type MIMO à trajets multiples. Dans un premier temps, nous considÂerons le canal à trajets multiples comme un modÃle MIMO convolutif et proposons une nouvelle technique dâestimation des coefficients. Cette technique non-paramÃtrique gÃnÃralise les mÃthodes proposÃes dans les chapitres prÃcÃdents pour les cas SISO et MIMO instantanÃ. En reprÃsentant le canal multi-trajet à lâaide dâun formalisme tensoriel, les paramÃtres physiques sont obtenus en utilisant une technique combinÃe de type ALS-MUSIC, basÃe sur un algorithme de sous-espaces. Enfin, nous considÃrons le problÃme de la dÂetermination dâordre de canaux de type RIF, dans le contexte des systÃmes MISO. Nous introduisons une procÃdure complÃte qui combine la dÃtection des signaux avec lâestimation des canaux de communication MISO sÃlectifs en frÃquence. Ce nouvel algorithme, basà sur une technique de dÃflation, est capable de dÃtecter successivement les sources, de dÃterminer lâordre de chaque canal de transmission et dâestimer les coefficients associÂes.

Ce travail de thèse présente une stratégie de transmission exploitant la diversité spatiale pour la transmission d'images sur canal sans fil. On propose ainsi une approche originale mettant en correspondance la hiérarchie de la source avec celle des sous-canauxSISO issus de la décomposition d'un canal MIMO. On évalue les performances des précodeurs usuels dans le cadre de cette stratégie via une couche physique réaliste, respectant la norme IEEE802.11n, et associé à un canal de transmission basé sur un modèle de propagation à tracé de rayons 3D. On montre ainsi que les précodeurs usuels sont mal adaptés pour la transmission d'un contenu hiérarchisé. On propose alors un algorithme de précodage allouant successivement la puissance sur les sous-canaux SISO afin de maximiser la qualité des images reçues. Le précodeur proposé permet d'atteindre un TEB cible compte tenu ducodage canal, de la modulation et du SNR des sous-canaux SISO. A partir de cet algorithme de précodage, on propose une solution d'adaptation de lien permettant de régler dynamiquement les paramètres de la chaîne en fonction des variations sur le canal de transmission. Cette solution détermine la configuration de codage/transmission maximisant la qualité de l'image en réception. Enfin, on présente une étude sur la prise en compte de contraintes psychovisuelles dans l'appréciation de la qualité des images reçues. On propose ainsi l'intégration d'une métrique à référence réduite basée sur des contraintes psychovisuelles permettant d'assister le décodeur vers la configuration de décodage offrant la meilleure qualité d'expérience. Des tests subjectifs confirment l'intérêt de l'approche proposée. / This thesis presents a transmission strategy for exploiting the spatial diversity for image transmission over wireless channel. We propose an original approach based on the matching between the source hierarchy and the SISO sub-channels hierarchy, resulting from the MIMO channel decomposition. We evaluate common precoder performance in the context of this strategy via a realistic physical layer respecting the IEEE802.11n standard and associated with a transmission channel based on a 3D-ray tracer propagation model. It is shown that common precoders are not adapted for the transmission of a hierarchical content. Then, we propose a precoding algorithm which successively allocates power over SISO subchannels in order to maximize the received images quality. The proposed precoder achieves a target BER according to the channel coding, the modulation and the SISO subchannels SNR. From this precoding algorithm, we propose a link adaptation scheme to dynamically adjust the system parameters depending on the variations of the transmission channel. This solution determines the optimal coding/transmission configuration maximizing the image quality in reception. Finally, we present a study for take into account some psychovisual constraints in the assessment of the received images quality. We propose the insertion of a reduced reference metric based on psychovisual constraints, to assist the decoder in order to determine the decoding configuration providing the highest quality of experience. Subjective tests confirm the interest of the proposed approach.

La integración de tecnologías de ulta-wideband, radio-cognitiva y MIMO representa una herramienta podersoa para mejorar la eficiencia espectral de los sistemas de comunicación inalámbricos. En esta dirección, nuevas estrategias para el modelado de canales MIMO y su caracterización se hacen necesarias si se desea investigar cómo la frecuencia central y el acho de banda afectan el desempeño de los sistemas MIMO. Investigaciones preliminares han enfocado menos atención en cómo estos parámetros afectan las características del canal MIMO. Se presenta una caracterización del canal MIMO en función de la frecuencia, abondándose puntos de vista experimentales y teóricos. Los problemas indicados tratan cinco áreas principales: medidas, post-procesado de datos, generación sintética del canal, estadística multivariable para datos y modelado del canal. Se ha diseñado y validado un sistema de medida basado en un analizador vectorial de redes y se han ejecutado medidas entre 2 y 12 GHz en condiciones estáticas, tanto en línea de vista como no línea de vista. Se ha propuesto y validado un procedimiento confiable para post-procesado, generación sintética de canal y análisis experimental basado en medidas en el dominio de frecuencia. El procedimiento experimental se ha focalizado en matrices de transferencia del canal para casos no selectivos en frecuencia, estimándose además las matrices complejas de covarianza, aplicándose la factorización de Cholesky sobre ls CCM y obteniéndose finalmente matrices de coloreado del sistema. Se presenta un procedimiento de corrección para generación sintética del canal aplicado a casos MIMO de grandes dimensiones y cuando la CCM es indefinida. Este CP permite la factorización de Cholesky y de dichas CCM. Las características multivariables de los datos experimentales han sido investigadas, realizándose un test de normalidad compleja multivariable. / García Ariza, AP. (2009). Modelling and experimental analysis of frequency dependent MIMO channels [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6563 / Palancia

Single Carrier Frequency Division Multiple Access (SC-FDMA) is a multiple access transmission scheme that has been adopted in the 4th generation 3GPP Long Term Evolution (LTE) of cellular systems. In fact, its relatively low peak-to-average power ratio (PAPR) makes it ideal for the uplink transmission where the transmit power efficiency is of paramount importance. Multiple access among users is made possible by assigning different users to different sets of non-overlapping subcarriers. With the current LTE specifications, if an SC-FDMA system is operating at its full capacity and a new user requests channel access, the system redistributes the subcarriers in such a way that it can accommodate all of the users. Having less subcarriers for transmission, every user has to increase its modulation order (for example from QPSK to 16QAM) in order to keep the same transmission rate. However, increasing the modulation order is not always possible in practice and may introduce considerable complexity to the system. The technique presented in this thesis report describes a new way of adding more users to an SC-FDMA system by assigning the same sets of subcarriers to different users. The main advantage of this technique is that it allows the system to accommodate more users than conventional SC-FDMA and this corresponds to increasing the spectral efficiency without requiring a higher modulation order or using more bandwidth. During this work, special attentions wee paid to the cases where two and three source signals are being transmitted on the same set of subcarriers, which leads respectively to doubling and tripling the spectral efficiency. Simulation results show that by using the proposed technique, it is possible to add more users to any SC-FDMA system without increasing the bandwidth or the modulation order while keeping the same performance in terms of bit error rate (BER) as the conventional SC-FDMA. This is realized by slightly increasing the energy per bit to noise power spectral density ratio (Eb/N0) at the transmitters.

Single Carrier Frequency Division Multiple Access (SC-FDMA) is a multiple access transmission scheme that has been adopted in the 4th generation 3GPP Long Term Evolution (LTE) of cellular systems. In fact, its relatively low peak-to-average power ratio (PAPR) makes it ideal for the uplink transmission where the transmit power efficiency is of paramount importance. Multiple access among users is made possible by assigning different users to different sets of non-overlapping subcarriers. With the current LTE specifications, if an SC-FDMA system is operating at its full capacity and a new user requests channel access, the system redistributes the subcarriers in such a way that it can accommodate all of the users. Having less subcarriers for transmission, every user has to increase its modulation order (for example from QPSK to 16QAM) in order to keep the same transmission rate. However, increasing the modulation order is not always possible in practice and may introduce considerable complexity to the system. The technique presented in this thesis report describes a new way of adding more users to an SC-FDMA system by assigning the same sets of subcarriers to different users. The main advantage of this technique is that it allows the system to accommodate more users than conventional SC-FDMA and this corresponds to increasing the spectral efficiency without requiring a higher modulation order or using more bandwidth. During this work, special attentions wee paid to the cases where two and three source signals are being transmitted on the same set of subcarriers, which leads respectively to doubling and tripling the spectral efficiency. Simulation results show that by using the proposed technique, it is possible to add more users to any SC-FDMA system without increasing the bandwidth or the modulation order while keeping the same performance in terms of bit error rate (BER) as the conventional SC-FDMA. This is realized by slightly increasing the energy per bit to noise power spectral density ratio (Eb/N0) at the transmitters.