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Coverage Map of Raufoss city, where the plotted dark circles are subscribers using the BS "Lønneberget" (arrow)
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Fixed WiMAX is being deployed worldwide, and the networks are increasing in size. Measurements have been performed, but the amount of measurements are few and do therefore not demonstrate performance in a real life deployment. We have performed extensive analyses of the physical performance in a fixed WiMAX deployment which has been operative for a...
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The IEEE 802.16 technology (WiMAX) is a promising technology for providing last-mile connectivity by radio link due to its large coverage area, low cost of deployment and high speed data rates. However, the maximum number of channels defined in the current system may cause a potential bottleneck and limit the overall system capacity. The aim of thi...
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... Technologies called Wireless to The Home (WTTH) provide wireless Internet services to headquarters, such as homes and companies, using several wireless standards. Examples of these standards include IEEE 802.16 [2] for the Worldwide Interoperability for Microwave Access (WiMAX) technology and IEEE 802.11 [3] for Wi-Fi versions, and recently Long-Term Evolution (LTE) or so-called 4G technology [4]. These networks fall in the FWA networks category [3]. ...
... To determine whether the results obtained from this study are consistent with the standard free-space PL equation (1), we created a separate dataset for the subscribers having: the same noise environment, the same type of CPE model, and connected to the same AP model. Fig. 10 shows a scatter plot for the dataset filtered according to these conditions and equation (2). Since we need to understand the relation between the distance and the received power at the CPE, we use a general logarithmic model (equation (3)) to fit this data. ...
Fixed Wireless Access (FWA) networks made substantial progress in providing
reliable wireless services for users everywhere. To the best of our knowledge, this is the first attempt in Libya to study and assess the performance of a realistic local FWA network operating on an unlicensed 5 GHz band despite the widespread networks of this type throughout the country. This paper provides a detailed analysis of several factors and measurements that affect network performance. The study depends on measurements extracted from a real dataset of an active FWA network. The central performance metric we consider is the capacity offered by the network to the subscribers. Using modern and powerful Python libraries, we present statistical summaries for those factors to estimate the impact of each one individually on the performance. Finally, we utilized the well-known free space Path Loss (PL) model behavior to demonstrate and validate the accuracy of our measurements.
... The MAC layer in WiMAX for downlink (DL) used Time Division Multiplex (TDM). And for uplink (UL), it used Time Division Multiple Access (TDMA) in (PMP) mode [12][13][14][15]. The 802.16 mesh mode in MAC layer is based on (TDMA) technology; this used the orthogonal multiplexing frequency division (OFDM) in the physical layer. ...
The Base Station (BS) is a WiMAX (Worldwide Interoperability for Microwave Access) centralized scheduling mesh topology decision maker for scheduling the whole network including allocation of packets between the Subscribers (SSs) in the network through the BS. Hence, the system, which, by interference, especially affects the nodes, close to BS. A network routing algorithm was built for mesh topology named Energy Bit Minimum Routing (EBMR), which is used to optimize the chosen path. all nodes were fitted with a multi-channel and four scenarios were planned: the first scenario is called the Multi-Transceiver fitted both SSs with a multi-transceiver except at the brink without cap the number of parent nodes. Whereas the second scenario was called Closest Multi-Transceiver system no ceiling on the number of parent nodes, in this scenario only the nearest BS is fitted with multi-transceiver SSs. The third scenario used the Multi-Transceiver system but with cap the number of parent nodes by 30% for whole nodes network. The fourth scenario used the closest Multi-Transceiver system but with cap, the number of parent nodes by 30%, for whole nodes network. In scenarios, the system content considers 120 users as maximum. It will improve the network capacity, throughput, channel scheduling range and channel utilization ratio (CUR). WiMAX mesh topology is used to centralize scheduling and improve the performance system by finding the best route to centralizing the mesh network EBMR; consequently, it increases latency, CUR and distance scheduling, avoiding messing, otherwise. Multi-transceiver network is used to prevent primary interference and multi-channel network used to stop secondary interference. This paper develops two styles of network: the multi-transceiver multi-channel network and the closest multi-transceiver multi-channel device that uses the Time Division Multiple Access (TDMA) algorithm for EBMR-CS 3,4 (Energy Bit Minimization Routing and centralized Scheduling). This algorithm is optimizing network efficiency by having higher throughput by preventing interaction with adjacent nodes and the scheduling duration and growing the device’s channel utilization ratio (CUR).
... Therefore, the SNR value is calculated based on the path losses value and the connection between two nodes is achieved only if the SNR value is higher than the threshold limit SNR values and the threshold for SNR value varies depending on the modulation type used in the network according to the equation below [8]. ...
The (BS) is a decision maker in WiMAX unified scheduling mesh topology for scheduling the whole network including packet distribution between the (SSs) in the network through the BS. Hence the device, which particularly affects the nodes close BS through interference. A unified network routing algorithm called Mesh Topology (EBMR) was developed, This algorithm use to maximize route chosen, and equipped all nodes with a multi-channel and planned two scenarios: the first scenario named the Multi-transceiver equipped all (SSs) with a multi-transceiver except at the brink. While the second scenario called closest, multi-transceiver system, in this scenario only the closest (BS) was fitted with the (SSs) by multi-transceiver that is known to be 35 per cent of the overall network nodes. Both scenarios can increase network performance, throughput, scheduling range, and usage ratio of channels (CUR).
... Ces études bien que très utiles restent de la simulation ou de l'analyse des traces et gardent donc les lacunes de ces méthodes. Comme modèles analytiques consacré aux réseaux 4G, nous pouvons citer les travaux de Grønsund, Engelstad, Johnsen et Skeie [70] mais également de Lin, Vucetic et Mao [71] qui s'intéressent aux variations de la qualité du lien radio dans les cellules employant la technique d'accès multiple OFDMA. Les premiers se concentrent sur des réseaux WiMAX tandis que les seconds se focalisent sur des réseaux LTE. ...
Afin de satisfaire le besoin toujours croissant en débit et offrir toujours plus de services, ce où que les utilisateurs se trouvent, les réseaux cellulaires évoluent rapidement vers des technologies caractérisées par une interface radio de plus en plus sophistiquée. Par exemple, alors que le déploiement des réseaux 4G ne faisaient que commencer, les premières mises à jour vers les solutions LTE-A étaient déjà planifiées par les opérateurs, et actuellement, les technologies 5G font l'objet de recherches actives à travers le monde. Ces changements rapides sont motivés par l'explosion du trafic mobile, comme le montrent des nombreuses études et observations sur les réseaux actuels. Ce trafic est principalement généré par des utilisateurs équipés de smartphones, tablettes, et autres équipements mobiles. Cependant, les réseaux actuels ont du mal à s'adapter à cette proportion toujours grandissante d'utilisateurs mobiles et à leur fournir un service adapté. Dans ce contexte, un des enjeux importants pour les opérateurs et équipementiers est de disposer d'outils efficaces pour évaluer les performances de leurs réseaux et mieux les dimensionner. Cette thèse porte donc sur le développement de modèles analytiques, à la fois précis et simples d'utilisation, permettant de répondre aux problèmes posés par l'évaluation de performances dans les réseaux cellulaires de nouvelle génération. Les modèles s'appuient sur la théorie des files d'attente et des processus stochastiques et permettent d'évaluer les performances d'un réseau et de ses utilisateurs en tenant compte de leur mobilité. Dans un premier temps, sont présentés tour à tour des modèles dédiés aux différents types de cellules rencontrées dans les réseaux cellulaires et aux utilisateurs qui visitent ces cellules. Dans un second temps, des modèles dédiés à un réseau cellulaire dans son ensemble sont présentés. Ces modèles réseaux combinent les précédents modèles dédiés aux cellules et un modèle de routage reproduisant le routage des utilisateurs mobiles entre les différentes cellules qui constituent le réseau. Tous les modèles proposés ont été pensés afin d'obtenir des expressions simples de l'ensemble des paramètres de performances du système. Cette simplicité associée à la rapidité de résolution rend possible les études de performance des systèmes les plus complexes, comme en témoignent les nombreux exemples inclus dans cette thèse.
... There are exist many methods for the design of optical transport networks [5,6] and wireless access networks [7,8,9]. However, for designing RoF technology that provides the base platform for the integration of wireless and optical network system. ...
... WiMAX is a telecommunication technology that offers transmission of wireless data with high throughput, great coverage, flexible Quality of Service support and extensive security [1]. According to [2], Air Interface technology has been used in WiMAX to enable internet access via point-to-multipoint links, with the advantage of none-line-of-sight (NLOS) from the base station. ...
Worldwide Interoperability for Microwave
Access or WiMAX is a wireless communication system that can provide long distance wireless broadband access with high data throughput in a point to multipoint connection and line of sight or non-line of sight environment. There are two variants of the WiMAX standard called Fixed and Mobile WiMAX. Fixed WiMAX 802.16 delivers point to multipoint broadband wireless access to our homes and offices. Whereas Mobile WiMAX 802.16e gives fully mobile internet access at higher broadband speeds than other broadband networks like Wi-Fi. The paper objective is to compare the performance of Fixed and Mobile WiMax network within the sub urban area by simulating several scenarios. Ten scenarios were created from previous works, by using an open source simulator called NCTUns 5.0. The simulations were based on the changes of system parameters which are base station’s antenna height and distance between Base Station (BS) and Subscriber Station (SS). Both Fixed WiMAX and Mobile WiMAX topology has been tested, and the percentages of performance degradation were analyzed and compared
... where P t indicates the transmission power, G t indicates the antenna gain in the transmitter, G r indicates the antenna gain in the receiver, PL indicates the path loss, and Noise indicates the thermal noise power. In the following experiments, the path loss (in dB) is based on the measurements in line-of-sight (LOS) transmission in WiMAX [20]. ...
Power-efficient multicast routing is an active research field in wireless networks because most network nodes are powered by battery. However, this kind of multicast routing only considers the transmission radius coverage without addressing whether the signal quality is able to meet bandwidth requirement of the users. In this article, by leveraging on the Maximum Ratio Combining signal processing technique, a novel cooperative multicast routing scheme that meets the Signal-to-Noise Ratio (SNR) requirements of the traffic demands in power efficient way is developed. This problem is formulated as an optimization problem where the objective is to minimize the total transmission power subject to the SNR constraint. This is a challenging cross-layer design problem to simultaneously consider the cooperative routing in the network layer and the SNR-aware power control in the physical layer. A heuristic algorithm called bandwidth-aware cooperative radius adjustment (BACRA) is proposed to tackle this problem. The basic idea of BACRA is to select the node with the maximum ratio of contributed SNR to the power (denoted as SNR/P) to expand its power one at a time until the SNR requirements are all satisfied. The BACRA is proved to be optimal in terms of the SNR/P performance ratio. Numerical results demonstrate that the BACRA outperforms the other heuristics under all tested cases, especially in stringent SNR requirements and sparse network.
... GPS coordinates were also available for each of the subscribers, which gave us the possibility to choose a Path Loss model with great precision due to the large amount of measurement points. The measurements will be affected by possible co-channel Interference (CCI) by the adjacent Base Stations, which can be solved by analyses of the linear definition of SNR and RSSI [6]. ...
... If possible, the SU is setup within Line of Sight (LOS) to the BS, but there are also SUs with Non Line of Sight (NLOS) conditions. The NLOS sites are mostly present in areas close to the BS, whereas LOS becomes more common and also more important at farther distances [6] This phenomenon is also observed in the other coverage maps, and confirms the great LOS coverage of WiMAX. Thus NLOS conditions are more commonly experienced by SUs located close to the BS, while LOS conditions are most frequent for SUs farther away from the BS. ...
Fixed WiMAX is being deployed worldwide, and the networks are increasing
in size. Measurements have been performed, but the amount of measurements
are few and do therefore not demonstrate performance in a real life
deployment. We have performed analyses of the physical performance in a
fixed WiMAX deployment. The analysis presented in this paper focus on
received signal strength and signals to noise ratio.
... WiMAX is a new broadband wireless technology that offers high throughput, great coverage, flexible Quality of Service (QoS) support and extensive security [2]. According to [3], WiMAX uses Air Interface technology to enable point-to-multipoint connectivity with the advantage of none-line-of-sight (NLOS) from the base station. ...
WiMAX (Worldwide Interoperability for Microwave Access) is an emerging wireless communication system that can provide wireless broadband access with high data throughput over long distance in a point-to-multipoint and line of sight or non-line of sight environment. There are two main classes of WiMAX called Fixed and Mobile WiMAX. The research objective is to evaluate the performance of Fixed WiMax network within the sub urban area by simulating several scenarios. The scenarios were created based on the changes of system parameters which are base station's antenna height and distance between Base Station (BS) and Subscriber Station (SS). The research is conducted by an open source simulator called NCTUns 5.0, developed by National Chiao Tung University. The Fixed WiMAX topology has been tested and the percentages of data rate degradation with the effects of system parameters were analyzed. Finally, the results obtained show that the performance degrades gracefully with the increasing distance between BS and SS. It is also concluded that 25 meters BS antenna is optimal enough to cover up to 5000 meters area because there is no significant change in the data rate when 50 meters antenna tower is applied.
... This PL is a function of the distance of separation, d of the nodes. Thus, we can calculate the PL using the NLOS equation [23] as follows ...
Being an emerging wireless broadband technology with numerous prospects, Worldwide Interoperability for Microwave Access (WiMAX)
not only provides high data rate but also the last mile solution for broadband wireless access (BWA). WiMAX enables both point
to multi-point (PMP) and mesh topologies solution. In centrally controlled WiMAX mesh mode, all data packets are routed to
the subscriber stations (SSs) via base station (BS). Thus, the BS link may be constantly congested with data traffic which
impacts the performance of the system. The goal of this paper is to create an efficient multi-hops routing with suitable scheduling
algorithm in WiMAX mesh networks (WMN). This algorithm is called energy/bit minimization routing and centralized scheduling
(EbMR-CS) algorithm. Here, a routing tree is constructed based on the energy/bit minimization (EbM). This algorithm looks
for a short path from the current node to BS, while the optimal path is achieved when the whole path has the lowest EbM. After
the route is fixed, and the traffic demanded at each node is known, the total traffic arriving at a node is centrally scheduled
such that the transmission interferences can be avoided. The proposed algorithm has considered some important design metrics
such as fairness, reuse timeslot, balanced load, concurrent transmissions and hop count. The result shows that the proposed
EbMR-CS algorithm has reduced the length of scheduling up to 43%. The system throughput and channel utilization ratio (CUR)
have been enhanced up to 68% and 45%, respectively.
