For real time service, not only the data rate, but also the packet delay should be guaranteed. In this paper, by exploiting the queue status information and channel status information, a novel framework of joint spati...
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ISBN:
(纸本)9781424413737
For real time service, not only the data rate, but also the packet delay should be guaranteed. In this paper, by exploiting the queue status information and channel status information, a novel framework of joint spatial-frequency scheduling for real time service in MIMO-OFDMA system is proposed, and some joint spatial-frequency scheduling algorithm is proposed based on modified largest weighted delay first (M-LWDF), quality guaranteed (QG) and packet loss ratio (PLR) priority function. Comparing the simulation results of MIMO 1times2 case, M-LWDF achieves best performance; QG and M-LWDF scheduler may support 20 video user with 500 kbps data rate in 10 MHz bandwidth, and the spectrum efficiency may approach 0.9 bps/Hz. while for MIMO 2times4 results, QG scheduler may achieve best performance comprehensively, and more than 50 video user can be supported in 10 MHz, and the spectrum efficiency may approach 2.5 bps/Hz.
Packet scheduling is lone of the key mechanisms that will be employed in the network nodes (routers and switches) for supporting real-time applications in a high-speed networking environment. We propose a new frame-ba...
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Packet scheduling is lone of the key mechanisms that will be employed in the network nodes (routers and switches) for supporting real-time applications in a high-speed networking environment. We propose a new frame-based packet scheduling algorithm which calculates and keeps an index for each flow in order to keep track of instantaneous bursts. With this approach, flows with small bandwidth shares which might be in need of momentary service can be detected. Our algorithm can be considered as a version of WRR with improved delay characteristics. After an introduction to packet scheduling issues, we describe the operation of our algorithm. We then give some simulation results showing the delay performance of the proposed algorithm under various traffic loads and show that the proposed algorithm has a better delay performance.
In this paper, a parallel loop self-scheduling scheme for heterogeneous PC cluster systems is proposed. Though the proposed scheme does allow users to choose parameters before the execution initialization phase, there...
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ISBN:
(纸本)0769522491
In this paper, a parallel loop self-scheduling scheme for heterogeneous PC cluster systems is proposed. Though the proposed scheme does allow users to choose parameters before the execution initialization phase, there are still weaknesses that motivate us to go further with new improvements in that scheme. For instance, a decision on a fixed and monotonous parameter can easily lead to invalid schedule by using previous input information. Thus, it is proposed in this paper a new scheme, where the scheduling parameter can be adjusted dynamically and fit into most widely available computer systems, in order to provide higher overall performance.
OFDMA is an attractive multiple access technique for packet-based mobile broadband wireless access for beyond 3G and 4G systems. Radio resource allocation in OFDMA can exploit multiuser diversity to increase system ca...
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OFDMA is an attractive multiple access technique for packet-based mobile broadband wireless access for beyond 3G and 4G systems. Radio resource allocation in OFDMA can exploit multiuser diversity to increase system capacity by implementing opportunistic scheduling techniques. This paper presents a new opportunistic scheduling scheme for OFDMA-based wireless multimedia networks. We focus the scheduling algorithm on the class of delay-sensitive packets that belong to interactive applications such as telephony and video streaming. We divide the scheduling decision into two sub-problems: the OFDMA subcarrier allocation and subsequently the subcarrier assignment. Both the sub-carrier allocation and assignment algorithms exploit multiuser diversity and are designed to provide fairness with respect to the realizable throughput per user, packet dropping ratios and packet delay distributions. We investigate various performance aspects of the proposed scheduling algorithm using actual MPEG-4 traffic traces under different system loading and requested deadline values. The results show the superiority of the proposed scheduling scheme and its excellent performance with respect to throughput, packet dropping, and delay distributions
This paper focuses on scheduling different hard real-time applications on a uniprocessor when the earliest deadline first algorithm is used as the local scheduler, and the global scheduler of the system could be fixed...
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This paper focuses on scheduling different hard real-time applications on a uniprocessor when the earliest deadline first algorithm is used as the local scheduler, and the global scheduler of the system could be fixed priority (FP) or earliest deadline first (EDF). Each application task could be periodic or sporadic, bound or unbound, with arbitrary relative deadline which could be less than, equal to or greater than its period. A number of different server types are considered. This paper presents an exact and efficient schedulability test for the application tasks based on the capacity demand criterion when the global scheduler could be FP or EDF, in some cases, it is necessary and sufficient. Schedulability tests which are necessary and sufficient for several types of dynamic servers are presented when the global scheduler is EDF.
An integrated technique for test scheduling and scan-chain division under power constraints is proposed in this paper. We demonstrate that optimal test time can be achieved for systems tested by an arbitrary number of...
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ISBN:
(纸本)0769513786
An integrated technique for test scheduling and scan-chain division under power constraints is proposed in this paper. We demonstrate that optimal test time can be achieved for systems tested by an arbitrary number of tests per core using scan-chain division and we define an algorithm for it. The design of wrappers to allow different lengths of scan-chains per core is also outlined. We investigate the practical limitations of such wrapper design and make a worst case analysis that motivates our integrated test scheduling and scan-chain division algorithm. The efficiency and usefulness of our approach have been demonstrated with an industrial design.
In recent years, numerous large-scale Wireless LANs (WLAN) have been deployed all over the world. However, the shortage of non-interfering channels makes it a challenge for WLANs to efficiently support real-time multi...
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In recent years, numerous large-scale Wireless LANs (WLAN) have been deployed all over the world. However, the shortage of non-interfering channels makes it a challenge for WLANs to efficiently support real-time multicast services. In this paper, we study the problem of efficient scheduling of real-time multicast flows . For mitigating interferences, we allow access-points (APs) to transmit simultaneously only if they are mutually non-interfering and our objective is minimizing the fraction of time used by the APs for servicing the multicast flows. We introduce two multicast strategies, the association strategy for which each user is restricted to receive flows only from its associated AP and the non-association strategy for which a user may also decode transmissions from other APs in its vicinity. Under both strategies, the scheduling problem of minimizing the multicast service time is NP-hard and we propose simple approximation algorithms with provable performance bounds. Our simulations clearly demonstrate that the proposed algorithms yield efficient multicast scheduling.
In this paper, a novel framework is proposed to integrate spectrum (resource) sharing into multihop scheduling in relay-assisted systems. This approach provides an effective solution to minimize the effect of extra re...
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In this paper, a novel framework is proposed to integrate spectrum (resource) sharing into multihop scheduling in relay-assisted systems. This approach provides an effective solution to minimize the effect of extra resources that are required in multihop transmission. Particularly, this approach can be combined with different topologies of resource scheduling to provide better performance in terms of throughput and coverage compared to benchmark non-sharing algorithms.
The problem of scheduling a set of sporadic tasks that share a set of serially reusable, single unit software resources on a single processor is considered. The correctness conditions are that: each invocation of each...
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The problem of scheduling a set of sporadic tasks that share a set of serially reusable, single unit software resources on a single processor is considered. The correctness conditions are that: each invocation of each task completes execution at or before a well-defined deadline; and a resource is never accessed by more than one task simultaneously. An optimal online algorithm for scheduling a set of sporadic tasks is presented. The algorithm results from the integration of a synchronization scheme for access to shared resources with the earliest deadline first algorithm. A set of relations on task parameters that are necessary and sufficient for a set of tasks to be schedulable is also derived. The proposed model for the analysis of processor scheduling policies is novel in that it incorporates minimum as well as maximum processing time requirements of tasks. The scheduling algorithm and the sporadic tasking model have been incorporated into an operating system kernel and used to implement several real-time systems.< >
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