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Next generation wireless networks are expected to be Heterogeneous consisting of several wireless technologies such as 3G, WLAN, WiMAX, LTE etc. Users of future mobile networks will be able to choose from different radio access technologies. These networks vary widely in service capabilities such as coverage area, bandwidth and error characteristics. Network selection is a challenging task in heterogeneous...
We investigate issues associated with integrated radio design. Multiple constraints (e.g., due to interference or component sharing) may prohibit integrated radios from operating at the same time instance. We examine constraints defined by integrated radio RF concurrency capability, and study WiFi performance under different radio RF concurrency levels. We performed detailed simulation study for WiFi/WiMAX...
QoS provisioning is an important issue in the deployment of broadband wireless access networks. The scheduling scheme is essential to guarantee the QoS requirements of different service classes. WiMAX Orthogonal Frequency Division Multiple Access (OFDMA) system specifies the Orthogonal Frequency Division Multiplexing (OFDM) symbol mapping in a rectangular shape manner. In this paper, we propose a...
Video streaming for IPTV is transferring to wireless mobile devices. This process poses questions of the video quality that will result and the suitability of the existing pseudo-streaming schemes for video transfer. This paper sets out the case for wireless broadband video streaming based on a simple negative acknowledgment (NACK) scheme, which for convenience is called broadband video streaming...
Broadband Wireless Access (BWA) offers QoS-aware broadband access through a wireless medium, being IEEE 802.16 one of the BWA standards. In it, the Base Station (BS) is responsible of allocating the required bandwidth by the rest of nodes, acting as a central controller. The other nodes, Subscriber Stations (SSs), have to send a bandwidth request to give the BS the knowledge about their needs, taking...
The seamless integration of heterogeneous wireless access networks is currently one of the issues of major interest in the field of telecommunication systems. In an early future technologies like UMTS, WLAN and WiMAX will give broadband access to users that perform their voice/video calls or data sessions without knowledge of the specific technology their terminals are using, following the paradigm...
The aim of this paper is to address one aspect of this challenge - how do we build affordable communication networks in developing regions by adapting technologies originally designed for the industrialized world to be appropriate and sustainable in the developing world environments It is in this context that the role of information and communication technologies (or ICTs) in development has been...
IEEE 802.16j mobile multi-hop relay network is proposed to enhance the system coverage, user throughput and the capacity of fixed/mobile broadband wireless access system in IEEE 802.16d/802.16e. Relay station (RS) enables data transmission between base station and end user when the channel is not good for transmission. Besides, one relay station also communicates with a pair of other relay stations...
The IEEE 802.16 standard defines MAC and physical layer protocols for broadband wireless access, however it does not specify any scheduling algorithm. In this paper, we propose a RED-based Weighted Fair Priority Queuing algorithm for inter-class scheduling and a channel aware algorithm for intra-class scheduling. Weights of the service classes are adaptive according to the QoS requirements of each...
WiMAX systems are beginning to spread as a wide-area wireless access technology that provides QoS support for future multimedia applications. Vendors have started to ship off-the-shelf hardware that addresses the market of broadband Internet coverage in sparsely populated areas. Facing a potentially large deployment of 802.16-based end-system connectivity, it is of vital interest to experimentally...
WiMAX (IEEE 802.16) has emerged as a promising radio access technology for providing high speed broadband connectivity to subscribers over large geographic regions. New enhancements allow deployments of relay stations (RSs) that can extend the coverage of the base station (BS), increase cell capacity, or both. In this paper, we focus on deploying RSs for the purpose of coverage extension. We propose...
Throughput is always an important element in both fixed and wireless networks. This paper presents ODBA (On_Demand Bandwidth Allocation) mechanism in WiMAX network. In order to solve the current issues faced in WiMAX network, and improve QoS demand, a new mechanism, ODBA is designed. Tt is an on demand bandwidth allocation mechanism for WiMAX. ODBA depends on the different characters of different...
IEEE 802.16 standards specify four types of services, while how to design an efficient scheduling algorithm remains an open issue. Manufacturers can implement their own scheduling algorithms depending on their specific requirements. There are a lot of scheduling algorithms proposed in the literature. Several scheduling algorithms propose hierarchical structures with strict priority or one-level scheduling...
WiMAX is the latest technology that has promised to offer broadband wireless access over long distance. The throughput of wireless communication such as WIMAX depends on number of parameters. These parameters include: packet size, transmission rate, signal to noise ratio, modulation techniques and channel conditions. All these variables are discussed using simulation, certain graphs have obtain optimum...
In this paper, we present a novel handoff selection algorithm based on hierarchy analysis and fuzzy evaluation, which is applied to solve the access network selection problem in the heterogeneous wireless network. Hierarchy analysis can effectively estimate the weights of evaluation factors. The evaluation matrix is built by analyzing the fuzzy evaluation model, in which RSS is introduced as a dynamic...
In this paper, we propose a ??sleep mode restriction?? scheme for improving the effective cell throughput of worldwide interoperability for microwave access (WiMAX) systems when a mobile station (MS) switches its serving network from WLAN to WiMAX in heterogeneous networks. In the previous scheme, a MS acquires the information related to vertical handover (VHO) from media independent handover (MIH)...
A new Packet Scheduler whose architecture is based on the cross-layer paradigm is proposed for the IEEE 802.16e standard of Mobile WiMAX networks. The scheduler combines functionalities derived from the use of the utility function concept from economics, for the satisfaction of the maximum packet delay from real time service flows, and the token bucket principle for the support of minimum throughput...
In this paper, gains of the codebook based CL-MIMO for down link WiMax system has been studied using system level simulations. The system level simulation is based on the IEEE 802.16 m evaluation methodology. The 2 times 2 and 4 times 2 antenna configurations, and 3 bits and 6 bits preferred matrix index (PMI) feedback codebooks are considered. Both the sub-band and wide band PMI feedback are studied...
The use of Broadband Wireless Access (BWA) technology is increasing due to the use of Internet and multimedia applications with strict requirements of end-to-end delay and jitter, through wireless devices. The IEEE 802.16 standard, which defines the physical (PHY) and the medium access control (MAC) layers, is one of the BWA standards. Its MAC layer is centralized basis, where the Base Station (BS)...
The IEEE 802.16 standard is expected to become a successful broadband wireless access solution, especially thanks to its ablility to provide high data rates, to differentiate services, and thanks to its interoperability, as promoted by the worldwide interoperability for microwave access (WiMAX) organization. We consider in this paper an Orthogonal frequency division multiple access (OFDMA)-based 802...
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