{"id":187,"date":"2011-03-24T23:19:13","date_gmt":"2011-03-24T22:19:13","guid":{"rendered":"https:\/\/samovar2022.int-evry.fr\/index.php\/2011\/03\/24\/soutenance-these-de-ismehene-chahbi\/"},"modified":"2020-09-04T18:47:16","modified_gmt":"2020-09-04T16:47:16","slug":"soutenance-these-de-ismehene-chahbi","status":"publish","type":"post","link":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/2011\/03\/24\/soutenance-these-de-ismehene-chahbi\/","title":{"rendered":"SOUTENANCE : Th\u00e8se de Ismehene Chahbi"},"content":{"rendered":"<p>Vendredi <strong>25 F\u00e9vrier<\/strong> 2011<\/p>\n<p><strong>\u00abExploitation des antennes multiples pour l&rsquo;optimisation dans les r\u00e9seaux sans fil.\u00bb<\/strong><\/p>\n<p>La th\u00e8se a \u00e9t\u00e9 soutenue par Ismehene Chahbi, doctorante du d\u00e9partement RS2M<\/p>\n<p>Vendredi 25 F\u00e9vrier 2011 \u00e0 10h00<\/p>\n<p>Sur le campus de T\u00e9l\u00e9com SudParis, 9 rue Charles Fourier \u00e0 Evry, en salle C06.<\/p>\n<p><strong>Jury<\/strong><\/p>\n<p>    * Prof. Khaldoun Al Agha, Universit\u00e9 de Paris XI (Rapporteur)<br \/>\n    * Prof. Abdelaziz Samet, Ecole Polytechnique de Tunisie (Rapporteur)<br \/>\n    * Prof. Guy Pujolle, Universit\u00e9 Pierre et Marie Curie (Examinateur)<br \/>\n    * Prof. Houda Labiod, T\u00e9l\u00e9com ParisTech (Examinatrice)<br \/>\n    * Prof. V\u00e9ronique V\u00e8que, Universit\u00e9 de Paris XI (Examinatrice)<br \/>\n    * Dr. Badii Jouaber, T\u00e9l\u00e9com SudParis (Encadrant)<br \/>\n    * Prof. Djamal Zeghlache, T\u00e9l\u00e9com SudParis (Directeur de th\u00e8se)<br \/>\n    * Prof. Sami Tabbane, Sup&rsquo;com Tunisie (co-Directeur de th\u00e8se)<\/p>\n<p><strong>R\u00e9sum\u00e9<\/strong><\/p>\n<p>\u00ab\u00a0Les r\u00e9centes avanc\u00e9es dans le domaine du traitement d&rsquo;antennes et dans la micro\u00e9lectronique ont fait na\u00eetre la technologie des antennes intelligentes connue sous le nom de \u00ab\u00a0smart antennas \u00ab\u00a0. Consid\u00e9r\u00e9e comme rupture technologique pour les r\u00e9seaux sans fil, les syst\u00e8mes d&rsquo;antennes intelligentes pourraient r\u00e9pondre aux exigences de plus en plus fortes des applications et services en termes de d\u00e9bit, de capacit\u00e9 et de connectivit\u00e9.<\/p>\n<p>Aujourd&rsquo;hui, les smart antennas sont exploit\u00e9es pour d\u00e9velopper plusieurs technologies incluant les syst\u00e8mes de commutation de faisceaux, les antennes adaptatives et les syst\u00e8mes MIMO (Multiple Input Multiple Output). L&rsquo;utilisation des antennes MIMO a \u00e9t\u00e9 reconnue comme une technologie-cl\u00e9, capable d&rsquo;accro\u00eetre nsid\u00e9rablement la capacit\u00e9 des r\u00e9seaux sans fil en exploitant diff\u00e9remment et mieux le spectre radio. Elle fait partie des r\u00e9cents et futurs standards tels que le 3GPP-LTE et le IEEE-802.11n.<\/p>\n<p>Dans cette th\u00e8se, nous nous sommes int\u00e9ress\u00e9s \u00e0 l&rsquo;exploitation des techniques multi-antennes dans le contexte des r\u00e9seaux mobiles. Nous nous sommes focalis\u00e9s principalement sur deux axes de recherche : la formation de faisceaux et le multiplexage spatial.<\/p>\n<p>Dans une premi\u00e8re \u00e9tude, nous avons propos\u00e9 un sch\u00e9ma de formation de faisceaux, bas\u00e9 sur la technique LCMV (Linearly Constrained Minimum Variance) et permettant de former des faisceaux plus adapt\u00e9s en cas de mobilit\u00e9. <\/p>\n<p>Dans cette solution, l&rsquo;incertitude sur la localisation des noeuds est compens\u00e9e par des faisceaux de largeurs adapt\u00e9es. De plus, dans le cas o\u00f9 les param\u00e8tres (vitesse et direction) de mouvement des noeuds sont connus, nous avons propos\u00e9 d&rsquo;exploiter des techniques simples d&rsquo;extrapolation afin de limiter les calculs complexes des m\u00e9thodes de poursuite continue (tracking), tr\u00e8s consommatrices en ressources.<\/p>\n<p>Dans une seconde \u00e9tude, nous avons propos\u00e9 une solution d&rsquo;ordonnancement bas\u00e9e sur la technique du multiplexage spatial qui est une caract\u00e9ristique fondamentale des syst\u00e8mes MIMO. L&rsquo;algorithme propos\u00e9 (SCLS : Stream-Controlled Multiple Access) exploite les informations inter-couches (cross-layer) : environnement radio de la couche PHY et charge de trafic de la couche LIEN. <\/p>\n<p>Il permet de choisir l&rsquo;ensemble des liens \u00e0 activer simultan\u00e9ment et d\u00e9termine sur chacun de ces liens, le nombre d&rsquo;antennes \u00e0 utiliser pour transmettre des flux parall\u00e8les. SCLS permet ainsi de minimiser le temps n\u00e9cessaire pour satisfaire les demandes de trafic et de maximiser le d\u00e9bit global utilis\u00e9 \u00e0 chaque instant.<\/p>\n<p>Dans la troisi\u00e8me \u00e9tude, nous avons consid\u00e9r\u00e9 la probl\u00e9matique d&rsquo;estimation des directions d&rsquo;arriv\u00e9e et de d\u00e9part. Nous avons propos\u00e9 un algorithme (E-Capon) d&rsquo;estimation conjointe de ces directions ainsi que du retard de propagation des trajets multiples dans un canal MIMO. <\/p>\n<p>Nous nous sommes bas\u00e9s sur la m\u00e9thode de Capon qui permet de r\u00e9duire la complexit\u00e9 de traitement pour offrir une estimation rapide et robuste des informations relatives \u00e0 la localisation des noeuds. Notre objectif est de concevoir une technique mieux adapt\u00e9e aux changements dynamiques de topologie que l&rsquo;on peut observer dans les r\u00e9seaux sans fil.\u00a0\u00bb<\/p>\n<hr \/>\n","protected":false},"excerpt":{"rendered":"<p>Vendredi 25 F\u00e9vrier 2011 \u00abExploitation des antennes multiples pour l&rsquo;optimisation dans les r\u00e9seaux sans fil.\u00bb La th\u00e8se a \u00e9t\u00e9 soutenue par Ismehene Chahbi, doctorante du d\u00e9partement RS2M Vendredi 25 F\u00e9vrier 2011 \u00e0 10h00 Sur le campus de T\u00e9l\u00e9com SudParis, 9 rue Charles Fourier \u00e0 Evry, en salle C06. Jury * Prof. Khaldoun Al Agha, Universit\u00e9 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ocean_post_layout":"","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"","ocean_second_sidebar":"","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"","ocean_custom_header_template":"","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"","ocean_menu_typo_font_family":"","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"","ocean_post_oembed":"","ocean_post_self_hosted_media":"","ocean_post_video_embed":"","ocean_link_format":"","ocean_link_format_target":"self","ocean_quote_format":"","ocean_quote_format_link":"post","ocean_gallery_link_images":"on","ocean_gallery_id":[],"footnotes":""},"categories":[7],"tags":[],"class_list":["post-187","post","type-post","status-publish","format-standard","hentry","category-uncategorized-fr","entry"],"_links":{"self":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/187","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/comments?post=187"}],"version-history":[{"count":1,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/187\/revisions"}],"predecessor-version":[{"id":2033,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/187\/revisions\/2033"}],"wp:attachment":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/media?parent=187"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/categories?post=187"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/tags?post=187"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}