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Worldwide Interoperability for Microwave Access (WiMAX) is a broadband wireless access (BWA) technology. It provides high data rate and multimedia service. It also supports Quality of Service (QoS) for various types of application. In this network, it is important to allocate appropriate resource to different class of service to guarantee the delay of real-time service and avoid the starvation of...
The purpose of a Beyond 4G (B4G) radio access technology, is to cope with the expected exponential increase of mobile data traffic in local area (LA). The requirements related to physical layer control signaling latencies and to hybrid ARQ (HARQ) round trip time (RTT) are in the order of ~1ms. In this paper, we propose a flexible orthogonal frequency division multiplexing (OFDM) based time division...
In this paper, a three-layered slot antenna with compact size and high gain is proposed at 5.4 GHz for Wi-MAX (5.2∼5.8 GHz) applications. Simulated gain of 12dBi and measured gain of 10.48dBi are achieved and the impedance bandwidth is 22.59%. The efficiency is measured of 97.23%. Measured and simulated results are in good agreement. The overall size of the antenna is 100×100 ×21.5 mm3.
This study presents a new approach to improve the echocardiogram transmissions overWiMAX networks. Using a compression method based on visualization modes and a reliable method that adapts to the channel conditions, overall performance results are improved compared to classical approaches. The echocardiogram transmission using a compression method based on visualization modes requires lower bandwidth...
A printed slot antenna for WLAN/WiMAX and UWB applications is proposed. The rounded corners of slot and spade-shaped exciting patch are applied to the pentagonal slot. The proposed antenna capably responds to extremely wide impedance bandwidth. For impedance matching enhancement, a tapered CPW transmission line is introduced. The impedance bandwidth over 138 % is obtained. The radiation patterns likely...
The Worldwide Interoperability for Microwave Access (WiMAX) is a set of technical standards based on IEEE 802.16 standard, WiMAX is an alternative solution for the deployment of broadband networks in the territories, whether or not covered by other technologies such as ADSL or cable. It provides flexibility in network deployment options and service and supports point-to-multipoint (PMP) and Mesh mode...
In WiMAX architecture to avoid congestion at the base station, a mechanism namely WiMAX Fair Intelligent Congestion Control (WFICC) was proposed in [11]. WFICC ensures that the traffic is scheduled in such a way that the base station output buffer operates around a target operating point, without violating the Quality of Service (QoS) requirements of connections. However, only preliminary results...
The aim of this paper is to explore the two most popular wireless networks IEEE 802.11 and IEEE 802.16 with a view to examine the challenges and issues involved in the integration of both the networks. The 802.11 or Wireless Fidelity (WiFi) is a low cost wireless access technology that supports low data rate within a short range. On the contrary, the IEEE 802.16 or WiMAX (Worldwide Interoperability...
SCIS is the State Company for Internet Services in Iraq that works as the main Internet Service Provider (ISP). After 2003 war in Iraq, there is extremely high demand for Internet service due to very long period of sanctions enforced on Iraq. However, satisfying such high demand is a challenging task; as the cost, number of subscribers and Quality of Service (QoS) are important factors that need to...
In this paper, a design of patch array antenna for WiMAX (Worldwide Interoperability Mobile Access) and WLAN (Wireless Local Area Network) applications is proposed. The antenna structure consists of a microstrip patch array of 3 by 3 OCFA (off centered feed array) that is coaxial feed through type antenna with Unbalanced characteristic whereby the feed line situated off centered λ/3 to the left and...
Future broadband wireless systems will address the need of capacity increase and support diverse Internet services. This paper deals with performance analysis that can be applied to OFDM(A)-based wireless system. Focusing on WiMAX technologies, two different analytical approaches are compared with simulation results. Then, a mean IP packet delay analysis is presented (considering a suitable IP packet...
In this paper a new cross-layer connection admission control (CAC) algorithm in WiMAX networks is proposed. The CAC algorithm makes the decisions whether accept or not the new connections based on the quality of channel communications. Moreover, the proposed CAC works together with an uplink scheduling mechanism which allocates the network resources in accordance with the information about the quality...
In this paper, we investigate various distributions to compute the signaling cost with contention based bandwidth request mechanism for best effort (BE) services. The code division multiple access (CDMA) based contention resolution is considered for bandwidth request. Previous studies calculated signaling cost with real time polling service (rtPS) and unsolicited grant service (UGS) that perform polling...
Quality of service (QoS) is an important issue in the deployment IEEE 802.16 networks with real-time and non-real-time traffic integration. IEEE 802.16j is an extension of IEEE 802.16 to support relay transmission. In this paper, we propose a dynamic hybrid distributed scheduling mechanism (DHSM) for IEEE 802.16j networks with non-transparent relay stations. First, we define a suitable priority for...
This paper addresses specific smart grid communication requirements. It considers a last-mile network based on an IEEE 802.16 cell deployed to cover a group of customers and serve their Energy Services Interfaces. Based on the communication requirements of smart grid last-mile applications and entities, we propose a traffic priority model and setup for the WiMAX air interface. Finally, we evaluate...
This paper discusses coexisting signal detection technique of the interference DAA (Detect And Avoid) operation. In this paper, the emission of the coexisting singles and their occupied frequency band detection technique for the MB-OFDM (Multi-Band OFDM) system is proposed in order to improve the DER (miss Detection Error Rate) and the FAR (False Alarm Rate). The received coexisting signal is assumed...
Multimedia applications over Internet, such as IPTV and video on demand (VoD), have become fast growing applications in recent years. Such applications have stringent QoS constraints in terms of bandwidth, delay and packet loss. As a consequence, broadband access networks play an important role for multimedia applications. There are two emerging technologies offering both high bandwidth and QoS support,...
In this paper, we focus on the bandwidth allocation issue in wireless access networks, which are made up of Ethernet Passive Optical Network (EPON) and Worldwide Interoperability for Microwave Access (WiMAX) networks, i.e., Fiber-Wire (FiWi) networks. Since the bandwidth allocation scheme largely determines the performance of the entire wireless access network, in the past decades, researchers have...
This paper presents the admission control mechanism which can minimise the overwhelming effect of limited radio resources as the demand for network service increases. The simulation study was conducted using NCTUns module with hierarchical Quality of Service (QoS) priority method. The result shows the proposed admission control mechanism is able to increase the number of subscriber being served and...
Mobile WiMAX is a promising broadband access technology providing wireless last mile connectivity. In the Time Division Duplex (TDD) mode, a WiMAX frame is divided into two parts: downlink and uplink subframes. The subframe division ratio is normally set to a fixed value, resulting in under-utilization of the downlink or uplink subframes. In this paper, we propose a dynamic downlink and uplink subframe...
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