Information raining has been shown to address the problem of delivering Internet access to high-speed rail passengers. However, a wireline repeater or heterogeneous wireless relay design complicates implementation. Recent developments in extending mobile multihop relaying to the IEEE 802.16e standard have made it feasible to deploy an information raining using a common radio and physical layer. Two automatic repeat request techniques and two network coding techniques are proposed. An upper and lower bound on delay is established for a single fully network coded relay system operating in static signal to noise ratio conditions. Simulations involving a physical layer model demonstrate that network coding schemes can attain the maximum downlink capacity.

Information raining has been shown to address the problem of delivering Internet access to high-speed rail passengers. However, a wireline repeater or heterogeneous wireless relay design complicates implementation. Recent developments in extending mobile multihop relaying to the IEEE 802.16e standard have made it feasible to deploy an information raining using a common radio and physical layer. Two automatic repeat request techniques and two network coding techniques are proposed. An upper and lower bound on delay is established for a single fully network coded relay system operating in static signal to noise ratio conditions. Simulations involving a physical layer model demonstrate that network coding schemes can attain the maximum downlink capacity.

IEEE 802.16標準中有所謂Mobile Multi-hop Relay（MMR）的概念，然而基地台覆蓋範圍不足及遮蔽效應等問題尚待解決，因此在IEEE 802.16j標準中提出Relay Station（RS）以提升網路傳輸量並增進無線通訊品質。在MMR中由於多了中繼傳輸站來傳遞資料，因此需要有較多的連線頻道，此外也不能保證所有頻道都處於良好狀態，所以會有很高的機率造成資料傳送失敗。混和自動重傳要求（Hybrid Automatic Repeat reQuest, HARQ）的提出便是用來保證資料傳遞成功的機制。HARQ在IEEE 802.16-2004就已被提出，然而我們發現該HARQ機制在802.16j中是不具效率的，而且也並無法確保QoS（Quality of Service）的要求。在本論文中我們改善Chen[4]所提出的Dynamic Pre-allocation HARQ（DP-HARQ）機制，藉由考慮slot分配不足及封包發生非連續錯誤時造成延遲時間增加等問題，並加入具服務品質感知（QoS aware）的機制，以降低整體延遲時間（delay）並能有效提高吞吐量（throughput）。最後，我們以具二個hop以上的模擬環境，證明我們所提出的方法優於802.16j的HARQ機制及Chen[4]的方法。 / Mobile Multihop Relay (MMR) had already been defined in IEEE 802.16 network. The major purpose of MMR is to efficiently extend the coverage of a base station and to solve the shadow fading problem. The Relay Station (RS) defined in IEEE 802.16j is thus proposed to fulfill these goals. Because of the MMR Relay Station, we need more channels to transmit packets. However we cannot guarantee that all chaneels are in good condtion, there might be a high probability of failure transmission. The Hybrid Automatically Repeat reQuest (HARQ) mechanism is therefor proposed to ensure the successful transmission. The HARQ proposed in IEEE 802.16-2004 is not sufficient in 802.16j. Besides it can not help to meet QoS (Quality of Service) requirements. In this reserch we improve Chen’s [4] Dynamic Pre-allocation HARQ (DP-HARQ) mechanism by considering some problems like lack of slot allocation and packet transmission failure with non-continuous error, etc. We add the QoS aware mechanism to reduce the overall delay time and improve the throughput effectively. Finally, we simulate three hops environment and show that our method outperforms both the standard IEEE 802.16j the HARQ mechanism and Chen’s [4] method.

<p>We are very thirsty in terms of everything to fulfil our needs in a sophisticated way, and this leads me choose the so called master thesis titled “Multihop Concept in Cellular Systems”.</p><p>This thesis introduces an approach towards the integration of relaying or multihop scheme in the next generation of cellular networks. In a multihop cellular architecture, the users send their data to the base station via relay station or with direct communication to the base station. These relay stations can either be the nomadic, fixed at specific location or users’ mobile station (i.e. mobile relay station). The main objective of this paper is to compare the difference between the relaying network architecture with different channel bandwidth as well as their performance gain. For this we integrate the relay station into conventional cellular networks using IEEE 802.16j (One of the standard introduced relay station concept in WiMAX) OFDMA (Orthogonal Frequency Division Multiple Access is a transmission technique that is based on many orthogonal subchannels (set of carriers) that transmits simultaneously). The results show that under certain conditions the throughput and coverage of the system has been increased with the introduction of the relay station in to cellular base station zone.</p>

IEEE 802.16e ¡]also known as Mobile WiMAX¡^ is currently the international MAC ¡]medium access control¡^ standard for wireless metropolitan area networks. To enhance the network throughput and extend the coverage of base station, IEEE then defined the 802.16j standard. Clearly, one of the popular applications for WiMAX is the multicast service. On the other hand, the design of power saving technologies is important since mobile stations are often powered by batteries. In this thesis, we study the maximum energy-efficient multicast scheduling ¡]MEMS¡^ problem for an IEEE 802.16j network with transparent mode. Specifically, the base station should determine how to schedule the multicast data in a multicast superframe such that the multicast energy efficiency of network is maximal. We first prove that the MEMS problem is NP-complete. Then on the basis of SMBC-AMC, we propose its variant, called SMBC-relay, to solve this problem. However, in SMBC-relay, the base station may send the same multicast data several times, wasting the scarce bandwidth. Hence we we propose a genetic algorithm-based multicast scheduling algorithm, called GAMS. One of the key features of GAMS is that the base station can control when to terminate the algorithm by stopping the evolution at any time. Simulation results show that GAMS significantly outperforms SMBC-relay in terms of multicast energy efficiency.

WiMAX is one of the rising communications technology which enables last mile broadband mobile wireless Internet connectivity. IEEE Std 802.16-2009 is the last accepted standard which targets mobile and fixed wireless broadband access. The standard defines two types of stations which are base and mobile stations. A base station has a wired connection to backhaul network and gives broadband wireless service to mobile stations. IEEE 802.16j standard which is an amendment to IEEE 802.16, introduces Multihop Relaying for increasing coverage and throughput. Deployment of relay stations, where the backbone network does not exist, is a cost effective solution. Two modes of operations are defined for relay station: transparent mode and non-transparent mode. Relays in transparent mode, are deployed for improving signal quality, so that mobile stations can use relay link for increasing throughput. In non-transparent mode, relays can send management packets, so that mobile stations, which are not in the direct reach of a base station, can connect to network through relay stations. In domain specific networks main data traffic is caused by the communication between subscribers in same region. In this thesis shortcut routing scheme is proposed as sending packets to destination directly through relay station for data traffic between two subscribers with a common relay. With shortcut routing, network throughput is increased by preventing links at higher layer in topology from becoming bottleneck. Moreover, by traversing fewer hops, latency decreases. We also propose traffic aware path selection method, where a path will more.

We are very thirsty in terms of everything to fulfil our needs in a sophisticated way, and this leads me choose the so called master thesis titled “Multihop Concept in Cellular Systems”. This thesis introduces an approach towards the integration of relaying or multihop scheme in the next generation of cellular networks. In a multihop cellular architecture, the users send their data to the base station via relay station or with direct communication to the base station. These relay stations can either be the nomadic, fixed at specific location or users’ mobile station (i.e. mobile relay station). The main objective of this paper is to compare the difference between the relaying network architecture with different channel bandwidth as well as their performance gain. For this we integrate the relay station into conventional cellular networks using IEEE 802.16j (One of the standard introduced relay station concept in WiMAX) OFDMA (Orthogonal Frequency Division Multiple Access is a transmission technique that is based on many orthogonal subchannels (set of carriers) that transmits simultaneously). The results show that under certain conditions the throughput and coverage of the system has been increased with the introduction of the relay station in to cellular base station zone.

Today, telecommunication is improving rapidly. People are online anywhere anytime. Due to increasing demand in communication, wireless technologies are progressing quickly trying to provide more services in a wide range. In order to address mobility and connectivity requirements of users in wide areas, Worldwide Interoperability for Microwave Access (Wimax) has been introduced as a forth generation telecommunication technology. Wimax, which is also called Metropolitan Area Network (MAN), is based on IEEE 802.16 standard where a Base Station (BS) provides last mile broadband wireless access to the end users known as Mobile Stations (MS). However, in places where high constructions exist, the signal rate between MS and BS decreases or even the signal can be lost completely due to shadow fading. As a response to this issue, recently an intermediate node specification, namely Relay Station, has been defined in IEEE 802.16j standard for relaying, which provides both throughput enhancement and coverage extension. However, this update has introduced a new problem / call admission control in non-transparent relay networks that support coverage extension. In this thesis, a Quality of Service (QoS) aware dynamic admission control algorithm for IEEE 802.16j non-transparent relay networks is introduced. Our objectives are admitting more service flows, utilizing the bandwidth, giving individual control to each relay station (RS) on call acceptance and rejection, and finally not affecting ongoing service flow quality in an RS due to the dense population of service flows in other RSs. The simulation results show that the proposed algorithm outperforms the other existing call admission control algorithms. Moreover, this algorithm can be interpreted as pioneer call admission control algorithm in IEEE 802.16j non-transparent networks.

Nous assistons ces dernières années à une émergence constante de nouvelles applications, notamment pour les services audiovisuels. Ces applications imposent au réseau un certain nombre de contraintes pour qu’elles puissent fonctionner correctement. Le développement de mécanismes permettant d’offrir une garantie à ces contraintes, est donc devenu un objectif crucial. La norme IEEE 802.16j est l’une des solutions sans fil qui propose plus de ressources afin de supporter les nouveaux services de télécommunications. Dans la présente thèse, nous focalisons notre étude sur la problématique de la qualité de service dans les réseaux WiMAX relais. Nos contributions se regroupent à travers les étapes ci-dessous : Nous proposons un protocole de routage multicast pour les services IPTV (HDTV, SD-TV, Web-TV et Mobile-TV). Ce protocole repose d’une part sur un nouveau mécanisme de construction de l’arbre multicast basé sur les nombres premiers et d’autre part, sur une nouvelle méthode d’agrégation basée sur le standard de compression Vidéo «SVC». L’objectif est de supporter l’hétérogénéité des utilisateurs tout en optimisant la consommation des ressources. Par ailleurs, nous étudions le problème d’ordonnancement dans les réseaux WiMAX. Nous proposons un algorithme d’ordonnancement adaptatif AWRR, ce dernier se base sur une technique à charge pondérée. L’objectif est d’ajuster dynamiquement le poids de chaque classe de service, en prenant en compte la charge de la file d’attente et les contraintes de la QoS. Enfin, nous nous intéressons à l’étude de la problématique du chemin optimal contraint. Nous proposons une solution déterministe basée sur une fonction de coût. Notre fonction permet aussi d’assurer le contrôle d’admission, elle se base sur deux fonctions de coût élémentaires qui prennent en compte quatre critères de QoS. / Over recent years, new applications steadily developed in a tremendous space, especially in audiovisual services area. The present applications have some of constraints to work properly. The developments of mechanism which enable to overcome these constraints become a critical issue in this area. The IEEE 802.16j standard is one of wireless communication technology which offering more resources to support new telecommunication services. In this thesis, we focus our research on the problem of quality of service (QoS) inWiMAX relay networks. Our contributions are classified as follows : we proposed a multicast routing protocol for IPTV services (such as HD-TV, SD-TV, Web-TV and Mobile-TV). This proposed protocol used a new multicast tree construction mechanism based-on prime numbers. We also developed a new aggregation method based on standard video compression called Scalable Video Coding (SVC). Our goal is to support user’s heterogeneity while optimizing resources consumption. In addition, we studied the problem of scheduling inWiMAX networks.We proposed an adaptive scheduling algorithm AWRR for IPTV services. The aim of this method is to support QoS constraints by using two schedulers, and assigning a dynamic value to each service queue. Finally, we interested to study about the problem of path selection. We proposed a solution based on a deterministic cost function. This function also ensures admission control based on two basic cost functions which include four QoS criteria. This thesis has been prepared in the MIPS/GRTC laboratory, University of Haute Alsace, under a research contract external (CRE) framework with France Telecom R&D. All proposed mechanisms were evaluated by the simulator QualNet, Matlab and mathematical analysis.