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TCP is the main transport-layer communication protocol in traditional wired networks. This is also due to its efficient behavior in presence of congestion events. However, networks with wireless links and mobile hosts provide significant non-congestive losses due to bit error rate, host motion and handover mechanisms. TCP incorrectly interprets these events as a sign of network congestion, throttling...
WiMAX is a Worldwide Interoperability for Microwave Access. The technology is specified by the Institute of Electrical and Electronics Engineers Inc., as the IEEE 802.16 standard that works on development of globally standardized protocols for wireless MAN and it has been commercialized under the name “WiMAX”. 802-16-2004 has often been considered the “fixed standard” or “fixed WiMAX” and 802.16-2005...
Currently evolving wireless communication systems (e.g. LTE-A, WiMAX) are based on linearly precoded MIMO OFDM and utilize adaptive modulation and coding to adjust the code rate and modulation alphabet to the current channel conditions. For this purpose the transmitter requires channel knowledge, which is provided by means of receiver feedback, utilizing the rank, precoding matrix and channel quality...
This paper presents the performance analysis of various relay stations in IEEE 802.16j Mobile Multi-hop Relay (MMR) WiMAX for half and full duplex communication. The main function of Relay Station (RS) is to enhance the network capacity and extends the coverage area. The efficiency of RS is evaluated based on the throughput for downlink and uplink transmission.
The handover performance in mobile network is the most important factor that can influence the Quality of Service (QoS). Today many countries in the world have migrated to more advanced mobile communication system such as the IEEE 802.16e mobile WiMax network. This mobile WiMax has been proven to be more stable and applicable for fixed, portable, nomadic and mobile network. The parameters such as...
For the past few years, wireless networks have played bigger role in connecting people. Demand for it services has increased tremendously. In order to provide better services and choices for high-speed internet access and multimedia service for business and residential customer, IEEE has come out with new solution. Started on 2001, IEEE 802.16 working group was developing the IEEE 802.16 standards...
The attention on WiMAX and WiFi technologies are rapidly progressing and now it is common to find them not just in laptops and personal digital assistants (PDAs), but in equipment as mobile phones, parking meters, security cameras and home entertainment equipment. A combination of WiFi and WiMAX deployment, will offer more cost-effective solution than a sole WiMAX or WiFi implementation. Its technology...
Proxy Mobile IPv6 (PMIPv6) is a network-based mobility support protocol and it does not require MNs to be involved in the mobility support signaling. In flow mobility support, although the virtual interface in the MN solved the problems of vertical handover or flow mobility in heterogeneous network, missing procedure of MN-derived flow handover makes flow mobility in PMIPv6 incomplete. In this paper,...
Radio Resource Management (RRM) techniques used in the Worldwide Interoperability for Microwave Access (WiMAX) can provide for many of the services and features promised by 4G wireless networks, such as supporting multimedia services with high data rates, and wide coverage area, as well as all-IP with security and Quality of Service (QoS) support. The IEEE 802.16 standard, associated with the WiMAX,...
The emerging WiMAX technology (IEEE 802.16) is a fourth generation standard for low-cost, high-speed and long range wireless communications for a large variety of civilian and military applications. IEEE 802.16j has introduced the concept of mesh network model and a special type of node called Relay Station (RS) for traffic relay for Subscriber Stations (SSs). A WiMAX mesh network is able to provide...
Interest in Broadband Wireless Access (BWA) has been growing due to its high speed data rate, wide area coverage and support for Quality of Service (QoS) requirement for different applications. There is a need for better scheduler to handle diversified QoS while increasing system efficiency. In this paper, we propose an Improvised-Modified Deficit Round Robin (I-MDRR) that not only meets the QoS requirements...
This paper addresses the important performance issues that arises when multimedia traffic is carried over WiMAX systems. In future, WiMAX will be used in conjunction with other wireless systems to bring a variety of multimedia services. This paper presents the results of application testing using commercially available WiMAX products. The main focus is to show the effectiveness of QoS capabilities...
To take full advantage of wireless mesh networks and cooperative transmission simultaneously, a WiMAX-based cooperative PMP/Mesh hybrid topology, CoWiMAX is presented in this paper. Firstly, a hierarchy mesh topology and a PMP/Mesh hybrid frame structure are introduced for CoWiMAX. Secondly, a cooperative PMP and relay transmission scheme is presented to support cooperative PMP and relay links. Simulation...
Since the IEEE 802.16 first standard was proposed in 2004 to provide broadband wireless service, the standard has not only been widely studied, but also broadly commercialized. The current IEEE 802.16-2009 standard document specifies five Quality of Service classes. As is typical with most standards, IEEE 802.16 does not require the use of a specific scheduler. In this paper, we first evaluate the...
IEEE 802.16 mesh mode is positioned to be used as a wireless backbone network. In coordinated distributed scheduling (C-DSCH), when nodes transmit control messages to compete for channel access, they need to wait for some period of time called hold-off time to compete again. Network performance is sharply affected by the hold-off mechanism in the bandwidth reservation procedure. In this paper, a new...
IEEE 802.16 based Worldwide Interoperability for Microwave Access networks (WiMAX) are increasingly being deployed for last hop broadband wireless access. In order to provide the high speed access to information resources broadband technology like WiMAX is needed. In this paper we compared different uplink scheduling algorithms of WiMAX mainly maximum carrier to interference and noise (Max C/I) algorithm...
In this paper, an area-efficient decoder architecture is proposed for the quasi-cyclic low-density parity check (QC-LDPC) codes specified in the WiMAX 802.16e standard. In order to achieve low area and maximize hardware utilization, the decoder utilizes 4 decoding function units, which is the greatest common divisor of the expansion factors. Furthermore, the decoder adopts a novel scheduling scheme,...
This paper presents an efficient architecture to handle memory conflicts of a unified turbo decoder which supports multiple standards like HSPA+, 3GPP-LTE, WiMAX, 3GPP2-CDMA2000 and CCSDS. A unified radix-4 turbo decoder is used as the reconfigurable unit which provides double throughput for some standards. A complete memory conflict analysis for different interleaver patterns has been performed and...
This paper presents results from a novel OFDMA multi-cell mobile broadband system-level simulator. The tool is used to statistically characterize uplink and downlink inter-cell interference. Fully loaded interference studies cannot be performed on real-world networks until they have been fully deployed. As such, interference analysis and management must be accurately performed pre- deployment using...
Abstract - High-speed mobility has been a central issue to telecommunication in both theory and practice. Each generation of technology presents unique design and engineering challenges in products and deployments. It is especially critical to a class of upcoming 4G (4th-Generation) mobile broadband systems because of broader spectrum usage, aggressive modulation schemes, and sophisticated adaptation...
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