{"id":65279,"date":"2018-03-09T22:53:21","date_gmt":"2018-03-09T22:53:21","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/contributions-to-the-evaluation-and-enhancement-of-wlan-ieee-802-11-medium-access-control-mechanism\/"},"modified":"2018-03-09T22:53:21","modified_gmt":"2018-03-09T22:53:21","slug":"contributions-to-the-evaluation-and-enhancement-of-wlan-ieee-802-11-medium-access-control-mechanism","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/tecnologia-de-las-telecomunicaciones\/contributions-to-the-evaluation-and-enhancement-of-wlan-ieee-802-11-medium-access-control-mechanism\/","title":{"rendered":"Contributions to the evaluation and enhancement of wlan ieee 802.11 medium access control mechanism"},"content":{"rendered":"

Tesis doctoral de Mar\u00eda Elena L\u00f3pez Aguilera <\/strong><\/h2>\n

Since the sudden growth of the internet into the commercial world, several sorts of networks that use the internet protocol have emerged to provide access to it. Among these new networks employing ip, wireless technologies can be found. It is now commonplace to use portable devices to connect to the internet through the wireless medium. specifically, wireless local area networks (wlan) are being extensively deployed in many areas to provide easy and tetherless access. Besides, wlans will be part of future wireless mesh networks (wmn), which aim at deploying an ubiquitous internet, allowing connectivity of any kind of device, anytime and anywhere. Nowadays, the success of wlan technology and its important increase in the number of users lead to new challenges. In this thesis the author concentrates on different topics concerning the working mechanism of its medium access control (mac) layer. The author centers her evaluation of the mac layer on wlan ieee 802.11 technology, because, since its appearance for commercial use, it has restrained the employment of other wlan technologies. since the definition of the first ieee standard for wlan, the ieee 802.11, many variants and modifications have been proposed to improve its performance. Much research effort has been spent on improving the performance of its mac, which complements the increase in bit rate in the new versions of the standard (ieee 802.11a\/b\/g and the forthcoming ieee 802.11n). In any case, to estimate the improvement, modified access methods are usually compared under ideal channel conditions, which does not agree with real scenarios. Thus, first, this thesis evaluates the performance of various wlan access methods in realistic environments, taking into account the presence of transmission errors and of interfering neighbor cells with exposed terminals. Moreover, the author identifies a performance problem that arises in wlan ieee 802.11 operating in the infrastructure mode. In this scenario the traffic load in the system is asymmetric, i.E. Most of the traffic goes through the access point and this station becomes the bottleneck of the system. Thus, the author proposes several mechanisms to prioritize access point transmissions and thus to cope with its overloaded condition. Next, the author concentrates on qos in wlan. It has been shown that in heavy loads, ieee 802.11e prioritization mechanism leads to the starvation of low-priority traffic. The author proposes a way to cope with this problem; it prioritizes independent collision groups and reduces the collision probability of stations. Besides, this thesis discusses about control traffic in wlan thus quantifying the influence of beacon frames for different sizes, periods and transmission rates. Next, the author shows the relation between propagation delay and mac performance. The thesis provides coverage ranges where the operation of wlan mac is feasible and results show the performance dependence on delay conditions for both hotspot and radio link scenarios. Finally, the thesis concludes with the evaluation of wlan mac in large multicell environments. The author identifies performance problems and provides mechanisms to reduce the interfering power level and to homogenize the behavior of stations placed at different spatial positions with respect to the access point. These methods consist in the employment of channel assignment schemes, the use of sectorised antennas at the access points and transmit power control mechanisms. to carry out the evaluation on each different topic, the author has used both simulation and analytical results. The simulation tool employed and the analytical models obtained allow accurate modeling of ieee 802.11 mac performance.<\/p>\n

 <\/p>\n

Datos acad\u00e9micos de la tesis doctoral \u00abContributions to the evaluation and enhancement of wlan ieee 802.11 medium access control mechanism<\/strong>\u00ab<\/h3>\n
    \n
  • T\u00edtulo de la tesis:<\/strong>\u00a0 Contributions to the evaluation and enhancement of wlan ieee 802.11 medium access control mechanism <\/li>\n
  • Autor:<\/strong>\u00a0 Mar\u00eda Elena L\u00f3pez Aguilera <\/li>\n
  • Universidad:<\/strong>\u00a0 Polit\u00e9cnica de catalunya<\/li>\n
  • Fecha de lectura de la tesis:<\/strong>\u00a0 16\/06\/2008<\/li>\n<\/ul>\n

     <\/p>\n

    Direcci\u00f3n y tribunal<\/h3>\n
      \n
    • Director de la tesis<\/strong>\n
        \n
      • Jordi Casademont Serra<\/li>\n<\/ul>\n<\/li>\n
      • Tribunal<\/strong>\n
          \n
        • Presidente del tribunal: josep Paradells aspas <\/li>\n
        • andrzej Duda (vocal)<\/li>\n
        • ilenia Tirinnello (vocal)<\/li>\n
        • albert Banchs roca (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n

           <\/p>\n","protected":false},"excerpt":{"rendered":"

          Tesis doctoral de Mar\u00eda Elena L\u00f3pez Aguilera Since the sudden growth of the internet into the commercial world, several sorts […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[15928,15596,13227,2489],"tags":[49781,143982,143983,96994,16621,143981],"class_list":["post-65279","post","type-post","status-publish","format-standard","hentry","category-analisis-y-diseno-de-experimentos","category-politecnica-de-catalunya","category-simulacion","category-tecnologia-de-las-telecomunicaciones","tag-albert-banchs-roca","tag-andrzej-duda","tag-ilenia-tirinnello","tag-jordi-casademont-serra","tag-josep-paradells-aspas","tag-maria-elena-lopez-aguilera"],"_links":{"self":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/65279","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/comments?post=65279"}],"version-history":[{"count":0,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/65279\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/media?parent=65279"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/categories?post=65279"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/tags?post=65279"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}