With the next generation cellular networks making a transition to-wards smaller cells, two-hop OFDMA relay networks have become a dominant, mandatory component in the 4G standards (WiMAX 802.16j, 3GPP LTE-Adv). While ...
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ISBN:
(纸本)9781450301831
With the next generation cellular networks making a transition to-wards smaller cells, two-hop OFDMA relay networks have become a dominant, mandatory component in the 4G standards (WiMAX 802.16j, 3GPP LTE-Adv). While unicast flows have received reasonable attention in two-hop OFDMA relay networks, not much light has been shed on the design of efficient scheduling algorithms for multicast flows, thereby forming the focus of this work. We show that while relay cooperation is critical for improving multicast performance, it must be carefully balanced with the ability to multiplex multicast sessions and hence maximize aggregate multicast flow. To this end, we highlight strategies that carefully group relays for cooperation to achieve this balance. We then solve the multicast scheduling problem under two OFDMA sub-channelization models. We establish the NP-hardness of the scheduling problem even for the simpler model and provide efficient algorithms with approximation guarantees under both models. Evaluation of the proposed solutions reveals the efficiency of the scheduling algorithms as well as the significant benefits obtained from the multicasting strategy. Copyright 2010 ACM.
WiMAX (Worldwide Interoperability for Microwave Access) is a wireless technology that provides long distance broadband connectivity. It has high speed access, wide coverage areas, and provides various types of service...
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ISBN:
(纸本)9781509015689
WiMAX (Worldwide Interoperability for Microwave Access) is a wireless technology that provides long distance broadband connectivity. It has high speed access, wide coverage areas, and provides various types of services. Applying WiMAX has challenging problem when it has to provide quality assurance of service (QoS) for different types of services with diverse QoS needs. To meet the QoS requirements, a scheduling algorithm is needed. scheduling algorithm is to regulate the transmission of data packets, such as regulating the sharing of resources (bandwidth) for each user. This research implemented a WiMAX network simulation scheduling algorithm with homogeneous and hybrid algorithm methods. Representatives on the homogeneous algorithms method used Weighted Fair Queuing scheduling algorithm (WFQ) and Deficit Round Robin (DRR), whereas the hybrid algorithm method used a merge between DRR and WFQ scheduling algorithm. Testing the performance of the scheduling algorithm was performed by comparing the QoS class into 5 types, namely WiMAX UGS, RTPS, nRTPS, eRTPS and Best Effort. The parameters used to test the performance of a WiMAX network are throughput, packet loss, delay and jitter.
Cloud computing delivers a computing environment where different resources are delivered as a service to the customer or multiple tenants over the internet. Task scheduling is an essential and most important part in a...
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ISBN:
(纸本)9781467397469
Cloud computing delivers a computing environment where different resources are delivered as a service to the customer or multiple tenants over the internet. Task scheduling is an essential and most important part in a cloud computing environment. The task scheduling mainly focuses to enhance the efficient utilization of resources and hence reduction in task completion time. Task scheduling is used to allocate certain tasks to particular resources at a particular time instance. Many different techniques have been proposed to solve the problems of task scheduling. Task scheduling improves the efficient utilization of resource and yields less response time so that the execution of submitted tasks takes place within a possible minimum time. This paper discusses about the study of various scheduling algorithms in a cloud computing environment.
This paper provides a survey of the state-of-the-art workflow scheduling algorithms with the assumption of cloud computing being used as the underlying compute infrastructure in support of large-scale scientific workf...
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ISBN:
(数字)9781728187891
ISBN:
(纸本)9781728187907
This paper provides a survey of the state-of-the-art workflow scheduling algorithms with the assumption of cloud computing being used as the underlying compute infrastructure in support of large-scale scientific workflows involving big data. The survey also reviews a few selected representative scientific workflow systems in light of usability, performance, popularity, and other prominent features. In contrast to existing related surveys, which most try to be comprehensive in coverage and inevitably fall short in the depth of their coverage on workflow scheduling, this survey puts an emphasis on the two dominant factors in workflow scheduling, the makespan and the monetary cost of workflow execution, resulted in a useful taxonomy of workflow scheduling algorithms as an additional contribution. This survey tries to maintain a good balance between width and depth in its coverage - after a broad review, it spotlights on selected top ten representative scheduling algorithms and top five workflow management systems leveraging cloud infrastructure with an emphasis on support for big data scientific workflows.
This work provides some criteria that allow network administrators to measure the impact of different network configurations have on voice, data, and video applications quality of service offered to the different user...
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ISBN:
(数字)9781728173498
ISBN:
(纸本)9781728173504
This work provides some criteria that allow network administrators to measure the impact of different network configurations have on voice, data, and video applications quality of service offered to the different users. For that, this project implemented tests to measure parameters such as packet loss, delay and jitter using static routing, different packet scheduling algorithms (Custom Queuing, Priority Queuing, and Weighted First Queuing), different services (voice, data, and video), and connection speeds using Cisco 2800 Routers and D-ITG traffic generator in conjunction with the Network Time Protocol synchronizer. A comparative analysis of sensitive parameters for Quality of Service was conducted to describe network behavior for each service. The implemented services presented performances according to quality requirements, reported in the literature. Specifically, the data service presented delay and jitter within the levels considered acceptable for this application and zero packet loss. For its part, the video service presented levels of delay and jitter according to the quality requirements for streaming. Finally, the voice service presented the best configuration performance with the Priority Queuing algorithm, for all measured service quality parameters.
Location-awareness plays a key role in various applications in future wireless networks. In GPS-challenged environments, location-awareness can be achieved via wireless navigation networks, which call for an efficient...
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Location-awareness plays a key role in various applications in future wireless networks. In GPS-challenged environments, location-awareness can be achieved via wireless navigation networks, which call for an efficient scheduling algorithm to optimize the navigation performance under communication constraints. In this paper, we develop a general framework for the design and analysis of scheduling algorithms for navigation networks with multiple measurement pairs per time slot. In particular, we provide sufficient and necessary conditions for the stability of the error evolution, and derive bounds on the time-averaged network localization errors (NLEs) for opportunistic and random scheduling. Furthermore, we show that the two scheduling algorithms are optimal in terms of the error scaling with respect to the number of agents, and we quantify the performance gain from measurement pair selections exploiting the network states. These results provide guidelines for designing efficient scheduling algorithms for network navigation.
There are kinds of Internet applications such as VoIP, online gaming and video Conferencing which need quality of service guarantees making the performance analysis critical, and the traffic of such applications usual...
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There are kinds of Internet applications such as VoIP, online gaming and video Conferencing which need quality of service guarantees making the performance analysis critical, and the traffic of such applications usually exhibits the properties of self-similarity and heavy tail. In this paper, we use the generalized Stochastically Bounded Burstiness model to characterize the network traffic with self-similar property and self-similar property. And we derive the delay bounds for such kind of traffic in the system under three different scheduling algorithms: First In First Out, Static Priority and Generalized Processor Sharing. We utilize the relationships between the traffic-amount-centric stochastic arrival curves and the virtual-backlog-centric stochastic arrival curve as well as the relationships between the weak stochastic service curve and the stochastic service curve making the analysis of the performance bounds of the through traffic in the tandem systems feasible.
Distributed embedded systems (DESs) must be designed to meet temporal constraints enforced by an application. This usually means applying a message scheduling scheme optimized for a specific configuration that typical...
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ISBN:
(纸本)9781509023301
Distributed embedded systems (DESs) must be designed to meet temporal constraints enforced by an application. This usually means applying a message scheduling scheme optimized for a specific configuration that typically depends on the used network topology and various message attributes (e.g. message size). The optimization of the schedule is performed off-line, during the network configuration process, and usually cannot be easily adapted in case of sudden environment changes that would affect the current network configuration. The Flexible Time-Triggered (FTT) protocol brings the necessary flexibility to a DES by means of on-line scheduling policy management that is required for operation in dynamic environments. This paper presents an OMNeT++ simulation model aimed at evaluating the scheduling algorithms in FTT-SE networks. The model is assessed using different scenarios and two commonly used scheduling schemes, namely, Rate Monotonic Assignment (RMA) and Earliest Deadline First (EDF).
The grid computing offers powerful and dynamic framework, with the numerous resources, distributed CPU loads, along with the extent of idle memory continually altering. Efficient schedulers are required to schedule jo...
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The grid computing offers powerful and dynamic framework, with the numerous resources, distributed CPU loads, along with the extent of idle memory continually altering. Efficient schedulers are required to schedule jobs in such dynamic environment. This paper presents comparative study of various well-known grid computing based scheduling techniques by taking into account the implementation environment as well as metrics used like soft computing, environment and metrics used with the aim to determine the effectiveness of each existing optimizing technique. This study has shown that the Ant colony optimization scheduling has quite significant results over the available techniques. However due to slowing growing rate it also become bottleneck of the optimistic scheduling. This paper ends up with the suitable future directions to enhance the existing scheduling techniques.
LTE uses the SC-FDMA radio access technology for its uplink transmission. As a result, resources assigned to the same user must be contiguous in the frequency domain. Several uplink scheduling algorithms were proposed...
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LTE uses the SC-FDMA radio access technology for its uplink transmission. As a result, resources assigned to the same user must be contiguous in the frequency domain. Several uplink scheduling algorithms were proposed in the literature to fit that constraint. These algorithms take as input a matrix which is used by the Packet Scheduler for an efficient resource allocation. The performance of these algorithms is affected by the paradigm that is used to construct that matrix. Two main paradigms exist in the literature, channel dependent and proportional fairness. In this paper, we evaluate the performance of some LTE uplink scheduling algorithms for both channel dependent and proportional fairness paradigms. As a result, we identify the weaknesses of the existing paradigms and define some challenges for future enhancement.
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