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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...
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...
IEEE 802.16 is a Wireless Metropolitan Area Network (WMAN) technology that supports both high speed data transmission and quality of service (QoS). Other than the data speed, QoS is always another concern to the end users and applications. However, providing QoS in IEEE 802.16 is a challenging mission because it involved many components that interact with each other. One of the important components...
Five types of service flows are defined in the standard of IEEE 802.16. Each service flow has its own type of quality of service (QoS) requirement. Some scheduling algorithm is needed to satisfy the QoS requirement of each class. Traditional base station (BS) allocates bandwidth according to the request of user. However, the request may not equal to the real requirement in some situation. Thus, the...
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...
WiMAX (Worldwide Interoperability for Microwave Access) is emerging as one of the most promising technology for wireless communication network in metropolitan areas today. It is designed to provide different services such as voice, data and video with different type of QoS(Quality of Service). A scheduling scheme plays a very important role to achieve the QoS requirement. There are scheduling algorithms...
With the increase of Internet services and the intensive development of IP infrastructure, WIMAX technology is revolutionizing the broadband wireless world. This due to the low cost deployment, the high capacity and the large coverage. Quality of Service (QoS) is achieved through the use of five service classes (UGS, ertPS, rtPS, nrtPS, and BE), an Admission Control (AC) mechanism, a traffic policer...
The increasing demands for multimedia applications with various QoS requirements arouse the interest of researchers in the Fourth-generation wireless networks such as WiMAX. In order to ensure that the QoS requirements of these applications are met, effective scheduling algorithms must be designed. Even though it may be trivial to ensure that the minimum QoS of all service classes is attained, this...
In this paper, we propose a general model for the broadcast polling protocol of unsaturated IEEE 802.16 networks in which each subscriber station has a finite buffer. A subscriber station can be modelled as a M/G/1/K queue with its service time determined by the broadcast polling protocol. The buffer overflow probability, network throughput and packet delay performances are analyzed. The proposed...
According to the IEEE 802.16j standard, a Mobile Station (MS) connects with a Multi Relay-Base Station (MR-BS) through a Relay Station (RS). Because there could be multiple paths between a MS and a MR-BS, it is important for a MS to select an appropriate path to transmit data. Although many path selection schemes have been proposed, they are designed for delivering real-time data rather than best-effort...
WiMAX is one of the most interesting solutions for broadband wireless access, offering QoS features for multimedia traffics and applications. However, without the definition of a mandatory scheduling algorithm for the assignment of channel resources, WiMAX standard is open to enhancements by QoS research groups and developers. In this paper, BS uplink scheduling algorithms are considered and an innovative...
The WiMAX features longer transmission distance and more accomplished support of QoS than other wireless access technologies such as 802.11. Since the standard did not specify the QoS based packet-scheduling algorithms which run on the base stations, those algorithms are open for alternative implementations. In this paper, we propose a scheduling algorithm for burst traffic in the WiMAX base station...
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...
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...
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,...
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...
The existing IEEE 802.16 is a series of Wireless Broadband standards known as WiMAX as an important technology for providing high-speed Internet access to home and business subscribers in a wide area cellular network. It has defined real time and non-real time services. But the standard does not specify transmission scheduling schemes to support the services. In order to support the delay sensitive...
In this paper, we study the collision resolution protocol of the IEEE 802.16 standard for metropolitan broadband wireless access systems. The standard specifies the use of a random access scheme based on the slotted binary exponential backoff (BEB) algorithm during the bandwidth request phase. We analyze the distributed choice of the retransmission probabilities used by the BEB protocol. We follow...
One of the most popular applications of IEEE 802.16 network is to serve as a backhaul service for IEEE 802.11 networks. However, the traffic of an IEEE 802.16 connection aggregated from IEEE 802.11 networks fluctuates. Thus, efficient bandwidth reservation at the subscriber station (SS) is an importance issue. This study proposes a simple and flexible bandwidth reservation scheme at the SS, called...
This paper proposes a new scheduling algorithm for IEEE 802.16-2005 Broadband Wireless Metropolitan Area Networks in TDD mode. The proposed algorithm focuses on solving the problem of handling high priority traffic in congested networks while minimizing starvation conditions for other served classes. In this work, a detailed simulation study is carried out for the proposed scheduling algorithm as...
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