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In this paper, we investigate the spectrum scheduling problem for next generation multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) systems under QoS and interference constraints. Based on a constrained optimization problem formulation, we propose a cross-layer scheduling solution that takes into account the unlicensed UWB users channel and QoS conditions as well...
In new generation cellular networks, opportunistic schedulers take advantage from the delay-tolerance of data applications to ensure that transmission occurs when radio channel conditions are most favourable. “Proportional Fair” (PF) is a well-known opportunistic scheduler that provides a good compromise between fairness and efficiency when transmitting long flows. Unfortunately, the PF algorithm...
In cellular OFDMA networks, there exists a fundamental trade-off between the achievable cell capacity and the degree of fairness among the users in the cell. Several scheduling algorithms have been proposed which try to balance this tradeoff. The parameterization of these scheduling algorithms to achieve a certain desired fairness level is non-trivial. We show that the optimal fairness parameter settings...
In this paper, a joint channel-and-queue-aware relay selection and resource allocation scheme at the scheduling phase in an OFDMA downlink cellular network is proposed. The scheme can choose the best relay to cooperate and allocate subchannels and power for the source and the relay for the selected packet which can maximize the proposed utility function waiting in the base station. Under the premise...
The IEEE 802.16e standard provides a high degree of flexibility for setting up and operating mobile WiMAX networks in metropolitan environments. While the standard supports differentiated Quality of Service (QoS), crucial functions such as traffic scheduling and slot allocation are left as open issues to the research community. This paper focuses on these two features, that consist an NP-Hard problem,...
In this paper, a new joint scheduling and hybrid resource allocation method is derived and investigated for a multi-user downlink Orthogonal Frequency Division Multiple Access (OFDMA) system that provides Time Delay-Sensitive services (TDS) and Time Delay-Insensitive services (TDI). A three sectored multi-cellular heterogeneous traffic environment is considered where users are randomly distributed...
3GPP has specified that terminals can be configured to use either 2 or 10 ms transmission time interval in high speed uplink packet access systems. The purpose of this paper is to evaluate the benefit of exploiting a mixture of both of the transmissions time intervals within a cell instead of only one. The study is quantified by means of studying the achievable coverage of voice over IP and possible...
Packet scheduling algorithms are viewed as one of the key mechanisms for increasing the diversity order, robustness and effectiveness of a wireless multi-user communication system. Traditional packet scheduling are mainly designed to increase the system capacity. In this paper we present a novel scheduling algorithm that improves the scheduling energy efficiency in OFDMA based wireless cellular networks...
The transmission of stream media over the Internet require a high bandwidth. While the best-effort network could not provide constant transmission speed. The proxy server (PS) is the nearest part of the Internet to the client. The proxy can cache the data, and release the load of the servers. So the proxies have great influence on the video QoS. Through the perfect algorithm, within the acceptable...
Optimal assigning jobs to resources is an important problem in grid computing. Now grid scheduling policies are mostly traditional heuristic algorithms for scheduling n independent tasks on m processors in early finishing time. However grids have developed to wide area, heterogeneous and non autonomous environments, business objective also became crucial for the success of the scheduling. Therefore...
In this paper we focus on minimizing the long-term average power consumption of a single transmitter providing Quality of Service (QoS) enabled traffic to a single receiver. Both the transmitting and receiving stations are equipped with multiple antennas. First, we present a general {Kx M} system model where K is the number of independently buffered QoS streams and M is the number of parallel channels...
Providing guaranteed quality-of-service (QoS) for resource-hungry multimedia applications over wireless fading channels is challenging. Traditional layered architecture fails miserably in providing the QoS requirement of high throughput, low latency demand of these kinds of applications in wireless mobile networks. Cross-layer design approaches are critical for efficient utilization of the scarce...
QoS provisioning is an important issue for deploying broadband wireless access networks with real-time and non-realtime traffic integration. Opportunistic MAC (OMAC) protocol combines cross-layer design and opportunistic scheduling scheme to achieve high utilization while providing QoS supports to various applications. In this paper, we propose a cross-layer MAC protocol and scheduling framework with...
We present a State Estimation based Internet traffic flow control system where the objective is to maximize the aggregate bandwidth utility of network sources over their transmission rates. The network links and sources are viewed as processors of distributed computation and the control mechanism is based on estimation and optimization framework to solve the dual problem. The novelty of our approach...
The poor performance of TCP, designed about 30 years ago, over high bandwidth-delay product connections has attracted much attention in the past few years. Some research work attempt to solve this problem by using innovative window estimations. The bursty nature of packet transmission has compounded the challenges in the problem. In this paper, we propose a new transmission protocol - Fairness Control...
High concentration of users in a cell of a wireless LAN leads to an unsustainable traffic load at the access point (AP). An unsuitable solution to the problem will cause poor connectivity for users, severe performance degradation, and possible collapse of the wireless LAN. In this paper, we present a scheduler based on queue length at the AP and a congestion control scheme based on the channel utilization...
Managing hardware resources efficiently when they are shared in virtualized environment is a critical issue for improving application QoS. For CPU resources, virtual machine scheduling delays should be additionally concerned, because they cause unexpected service delays to guest applications and can consequently violate the application QoS. There have been many researches to manage CPU resources by...
Because of the dynamic nature and an instability of grid computing environment, system behavior in terms of QoS depends crucially on the selection of appropriate subset of the available resources. Thus, a well-defined system model that provides high system availability using a scheduling mechanism is required. In this paper, we propose the SLA based Policy Administrator (SPA) with QoS constraints...
Simulation is a significant way for performancespsila evaluations in switching and scheduling. The simulation software currently being existed has somewhat limitations in inheritability and extensibility. Based on current switching fabrics, by employing system level design method and object oriented technology, we designed and implemented a simulation platform called SPES for switching and scheduling...
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