208 research outputs found
A Fair and Efficient Packet Scheduling Scheme for IEEE 802.16 Broadband Wireless Access Systems
This paper proposes a fair and efficient QoS scheduling scheme for IEEE
802.16 BWA systems that satisfies both throughput and delay guarantee to
various real and non-real time applications. The proposed QoS scheduling scheme
is compared with an existing QoS scheduling scheme proposed in literature in
recent past. Simulation results show that the proposed scheduling scheme can
provide a tight QoS guarantee in terms of delay, delay violation rate and
throughput for all types of traffic as defined in the WiMAX standard, thereby
maintaining the fairness and helps to eliminate starvation of lower priority
class services. Bandwidth utilization of the system and fairness index of the
resources are also encountered to validate the QoS provided by our proposed
scheduling scheme
Opportunities for network development in Kazakhstan - WiMax
The purpose of this paper is to discuss Worldwide Interoperability for Microwave Access (Wimax) technology-based network deployment opportunities in Kazakhstan. To be widely adapted and be profitable, even the very promising technology with advantageous features must experience market testing and meet user needs. This project consists of two parts; the first part consists of analysis while the second part focuses on implementation. In the first part, the telecommunications industry of Kazakhstan is divided into three main segments: fixed communication, mobile communication, and internet & data communication. Some market characteristics are viewed based on data from National Statistics Agency of Kazakhstan, with the role of the segments in the telecommunications industry identified and their future growth discussed. With regards to Broadband Access Services, some user requirements are considered with e-government and e-commerce applications discussed. As a result of market research, a Mobile Wimax is selected for Broadband Access Services implementation for internet & data communication segment. The second part considers Wimax technology deployment in the access network. Distinctive features such as scalability, range, coverage and QoS; standard specifications, and modulation techniques are explained. The difference between “mobile” and “fixed” Wimax along with their target markets are discussed. Additionally, the approach for estimating user capacity requirements for a metropolitan area is reviewed. Further, a core element of access network Base Station deployments and review of Adaptive Antenna Configurations are provided. A comparative analysis regarding the number of required Base Stations in different implementation scenarios provided by Wimax Forum are reviewed
High frequency of low noise amplifier architecture for WiMAX application: A review
The low noise amplifier (LNA) circuit is exceptionally imperative as it promotes and initializes general execution performance and quality of the mobile communication system. LNA's design in radio frequency (R.F.) circuit requires the trade-off numerous imperative features' including gain, noise figure (N.F.), bandwidth, stability, sensitivity, power consumption, and complexity. Improvements to the LNA's overall performance should be made to fulfil the worldwide interoperability for microwave access (WiMAX) specifications' prerequisites. The development of front-end receiver, particularly the LNA, is genuinely pivotal for long-distance communications up to 50 km for a particular system with particular requirements. The LNA architecture has recently been designed to concentrate on a single transistor, cascode, or cascade constrained in gain, bandwidth, and noise figure
WIMAX LINK PERFORMANCE ANALYSIS FOR WIRELESS AUTOMATION APPLICATIONS
Wireless broadband access technologies are rapidly growing and a corresponding growth in the demand of its applicability transcends faster internet access, high speed file download and different multimedia applications such as voice calls, video streaming, teleconferencing etc, to industrial operations and automation. Industrial and automation systems perform operations that requires the transmission of real time information from one end to another through high-performance wireless broadband communication links. WiMAX, based on IEEE 802.16 standard is one of the wireless broadband access technologies that has overcome location, speed, and access limitations of the traditional Digital Subscriber Line and Wireless Fidelity, and offers high efficient data rates.
This thesis presents detailed analysis of operational WiMAX link performance parameters such as throughput, latency, jitter, and packet loss for suitable applicability in wireless automation applications. The theoretical background of components and functionalities of WiMAX physical and MAC layers as well as the network performance features are presented. The equipment deployed for this field experiment are Alvarion BreeZeMAX 3000 fixed WiMAX equipment operating in the 3.5 GHz licensed band with channel bandwidth of 3.5 MHz. The deployed equipment consisting of MBSE and CPE are installed and commissioned prior to field tests. Several measurements are made in three link quality scenarios (sufficient, good and excellent) in the University of Vaasa campus. Observations and results obtained are discussed and analyzed.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format
Performance analysis and application development of hybrid WiMAX-WiFi IP video surveillance systems
Traditional Closed Circuit Television (CCTV) analogue cameras installed in buildings and other areas of security interest necessitates the use of cable lines. However, analogue systems are limited by distance; and storing analogue data requires huge space or bandwidth. Wired systems are also prone to vandalism, they cannot be installed in a hostile terrain and in heritage sites, where cabling would distort original design. Currently, there is a paradigm shift towards wireless solutions (WiMAX, Wi-Fi, 3G, 4G) to complement and in some cases replace the wired system. A wireless solution of the Fourth-Generation Surveillance System (4GSS) has been proposed in this thesis. It is a hybrid WiMAX-WiFi video surveillance system. The performance analysis of the hybrid WiMAX-WiFi is compared with the conventional WiMAX surveillance models. The video surveillance models and the algorithm that exploit the advantages of both WiMAX and Wi-Fi for scenarios of fixed and mobile wireless cameras have been proposed, simulated and compared with the mathematical/analytical models. The hybrid WiMAX-WiFi video surveillance model has been extended to include a Wireless Mesh configuration on the Wi-Fi part, to improve the scalability and reliability. A performance analysis for hybrid WiMAX-WiFi system with an appropriate Mobility model has been considered for the case of mobile cameras. A security software application for mobile smartphones that sends surveillance images to either local or remote servers has been developed. The developed software has been tested, evaluated and deployed in low bandwidth Wi-Fi wireless network environments. WiMAX is a wireless metropolitan access network technology that provides broadband services to the connected customers. Major modules and units of WiMAX include the Customer Provided Equipment (CPE), the Access Service Network (ASN) which consist one or more Base Stations (BS) and the Connectivity Service Network (CSN). Various interfaces exist between each unit and module. WiMAX is based on the IEEE 802.16 family of standards. Wi-Fi, on the other hand, is a wireless access network operating in the local area network; and it is based on the IEEE 802.11 standards
Network Simulation and Performance Evaluation of WiMAX Extensions for Isolated Research Data Networks
IEEE 802.16 is yet a very recent technology and released hardware does frequently only support standards partially. The same applies to public available simulation tools, in particular for NS-2. As the latter is the de-facto standard in science and as we use it for our research in the context of the WEIRD project, we evaluate the IEEE 802.16 support for NS-2. We present several general but also specific issues, which areimportant in order to carry out reliable research based on thesetools. In particular, we show in much detail where modulesdeviate significantly and even fail totally
WiMax - a critical view of the technology and its economics
University of the Witwatersrand
Faculty of Engineering and the Built Environment
School of Information and Electrical EngineeringMobile Broadband is now more of a necessity than a luxury, especially amongst the younger generation, irrespective of where they live. Mobile WiMax and LTE, the latest and fastest Mobile Broadband technologies, mark significant improvements over 3G networks because they use IP (Internet Protocol) end-to-end. To end-users, this means faster network speeds, better quality services, and increased coverage area. To the Network Operators, this means simplified network architectures, efficient use of resources, and improved security. In this report, the different issues and challenges related to deploying Mobile WiMax (802.16e or 802.16m) in rural South Africa, were identifed and explored. In this project, Atoll, SONAR, and Touch Point analysis tools were used to determine which Mobile Broadband technology is economically and technically suited for rural South Africa. It was found that LTE yields superior performance results than WiMax, which in turn yields superior performance results to all other existing 3G technologies. However it will take time for LTE to reach rural areas therefore WiMax can be considered as a solution to extend Broadband services to rural South Africa and thus assist in bridging the digital divide. Recommendations on how best to deploy Mobile WiMax are made based on observations made from the experimental work.MT201
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Performance evaluation of fixed WiMax physical layer under high fading channels
This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.A radio channel characteristic modelling is essential in every network planning. This project deals with the performance of WiMax networks in an outdoor environment while using fading channel models. The radio channels characteristics are analyzed by simulations have been done using Matlab programming. Stanford University Interim(SUI) Channels set was proposed to simulate the fixed broadband wireless access channel environments where IEEE 802.16d is to be deployed. It has six channel models that are grouped into three categories according to three typical different outdoor Terrains, in order to give a comprehensive study of fading channels on the overall performance of the system, WiMax system has been tested under SUI channels that modified into account for 30o directional antennas, with 90% cell coverage and with 99.9% reliability in its geographical covered area. Furthermore, in order to combat the fading which occurs in urban areas and improve the capacity and the throughput of the system, multiples antennas at both ends of communication link are used, the transmission gain obtained when using multiple antennas instead of only a single antenna. Space-time coding and maximum ratio combining for more than one transmit and receive antenna is implemented to allow performance investigations in various MIMO scenarios. It has been concluded that uses multiple antennas at the receiver offers a significant improvement of 3 dB of gain in the channel SNR. This thesis also contain implementation of all compulsory features of the WiMax OFDM physical layer specified in IEEE 802.16-2004 using Matlab coding. In order to combat the temporal variations in quality on a multipath fading channel, an adaptive modulation technique is used. This technique employs multiple modulation schemes to instantaneously adapt to the variations in the channel SNR, thus maximizing the system throughput and improving BER performance. WiMax transceiver has been tested with and without encoding and studied the effect of encoding on multipath channel. Testing the system with flexible channel bandwidth has been part of this thesis. Finally it has been explained in this thesis the affect of increasing the size of cyclic prefix on overall performance of WiMax system
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