In this paper, an innovative scheduling scheme is proposed for interference-limited wireless multi-hop networks with non-deterministic fading channels. The scheduling problem is considered as a network utility maximiz...
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In this paper, an innovative scheduling scheme is proposed for interference-limited wireless multi-hop networks with non-deterministic fading channels. The scheduling problem is considered as a network utility maximization(NUM) problem subject to link rate constraints. With jointly considering link scheduling and the statistical variations of both signal and interference power, the convex sets for NUM are built. The subgradient projection method based on dual decomposition is employed to solve the convex optimization problem. Then a practical algorithm is designed for the TDM mode wireless multihop networks with minimizing the discrepancy between the expected network cost and the optimal value in each timeslot. The numerical results demonstrate the convergence and the improvement over network utility made by our proposed scheme.
We consider the problem of scheduling jobs with given start and finish times over two classes of multi-user channels, namely Multiple Access Channels and Degraded Broadcast Channels, and derive necessary and sufficien...
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We consider the problem of scheduling jobs with given start and finish times over two classes of multi-user channels, namely Multiple Access Channels and Degraded Broadcast Channels, and derive necessary and sufficient conditions for feasible scheduling of the jobs.
To provide flexibility in deploying new protocols and services, general-purpose processing engines are being placed in the datapath of routers. Such network processors are typically simple RISC multiprocessors that pe...
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To provide flexibility in deploying new protocols and services, general-purpose processing engines are being placed in the datapath of routers. Such network processors are typically simple RISC multiprocessors that perform forwarding and custom application processing of packets. The inherent unpredictability of execution time of an arbitrary instruction code poses a significant challenge in providing QoS guarantees for data flows that compete for such processing resources in the network. However, we show that network processing workloads are highly regular and predictable. Using estimates of execution times of various applications on packets of given lengths, we provide a method for admission control and QoS scheduling of processing resources. We present a processor scheduling algorithm called estimation-based fair queuing (EFQ) which uses these estimates, and provides significantly better delay guarantees than processor scheduling algorithms which do not take packet execution times into consideration.
Hybrid switch architecture with electronic buffering/processing and optical switching fabric is receiving a lot of attention as potential candidate for the design of high-performance and scalable switches/routers. How...
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Hybrid switch architecture with electronic buffering/processing and optical switching fabric is receiving a lot of attention as potential candidate for the design of high-performance and scalable switches/routers. However, the reconfiguration overhead of optical fabrics brings new challenges to system and scheduling algorithm design. For example, speedup is compulsory to make the switch stable; the scheduling rate has to be reduced compare to the traditional slot-by-slot scheduling in electronic switch. This paper provides instructions on how to choose speedup, scheduling algorithm and holding time. Main results include: 1) a speedup of 2 ensures switch stability and is cost-effective; 2) effect of reconfiguration delay is exaggerated at high traffic load and it is worth using complex scheduling algorithm; and 3) AVERAGE holding method performs better under most traffic scenarios.
In this paper we derive a stochastic primal-dual (SPD) algorithm for downlink/uplink scheduling of multiple connections with rate requirements, where each connection transmits using adaptive modulation and coding over...
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In this paper we derive a stochastic primal-dual (SPD) algorithm for downlink/uplink scheduling of multiple connections with rate requirements, where each connection transmits using adaptive modulation and coding over a wireless fading channel. Based on quantized channel state information at the transmitters, we derive the information-theoretic optimal downlink and uplink resource allocation/scheduling strategies. When the fading statistics are not known a priori, we develop an SPD algorithm which can dynamically adapt the scheduling policy online. We established analytically and confirm by simulations that with affordable complexity, this SPD algorithm asymptotically converges to the optimal scheduling strategies from any initial value.
This paper focuses on the study of scheduling techniques in HSDPA system. In this context, we propose to use the score based (SB) scheduling algorithm in HSDPA. This algorithm is compared to another scheduling algorit...
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This paper focuses on the study of scheduling techniques in HSDPA system. In this context, we propose to use the score based (SB) scheduling algorithm in HSDPA. This algorithm is compared to another scheduling algorithm, called proportional fair (PF), widely used and studied in the literature. To make this comparison, an analytical model allowing to evaluate the cell capacity and the user bit rate is proposed. The radio channel is assumed to he a dense multipath frequency selective channel with uncorrelated signal envelope following a Rayleigh distribution and wide-sense stationary uncorrelated scattering (WSSUS). Results show that SB seems to be a better trade-off between "fairness" and "efficiency" than PF
Task scheduling still remains one of the most challenging problems to achieve high performance in heterogeneous computing environments in spite of numerous efforts. This paper presents a novel scheduling algorithm bas...
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Task scheduling still remains one of the most challenging problems to achieve high performance in heterogeneous computing environments in spite of numerous efforts. This paper presents a novel scheduling algorithm based on learning classifier system for heterogeneous computing environment. In the presented algorithm, XCS classifier system is used to find the optimal task assignment on different processors, and the execution sequence of tasks on the same processor is set by the heuristic used in list scheduling approach. Empirical studies on benchmark task graphs show that the proposed algorithm is able to produce higher speedup compared with the related algorithms. Further experiments also indicate that the proposed algorithm maintains almost the same performance with different parameter settings.
We argue that the key underpinning of the current state-of-the real-time practice - the priority artifact - and that of the current state-of-the real-time art - deadline-based timeliness optimality - are entirely inad...
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We argue that the key underpinning of the current state-of-the real-time practice - the priority artifact - and that of the current state-of-the real-time art - deadline-based timeliness optimality - are entirely inadequate for specifying timeliness objectives, for reasoning about timeliness behavior, and for performing resource management that can dependably satisfy timeliness objectives in many dynamic real-time systems. We argue that time/utility functions and the utility accrual scheduling paradigm provide a more generalized, adaptive, and flexible approach. Recent research in the utility accrual paradigm has significantly advanced the state-of-the-art of that paradigm. We survey these advances.
The paper presents the application of a new analytical model of the full-availability group carrying a mixture of different multi-rate traffic classes with compression property for modeling the WCDMA radio interface w...
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The paper presents the application of a new analytical model of the full-availability group carrying a mixture of different multi-rate traffic classes with compression property for modeling the WCDMA radio interface with packet scheduling. The proposed model can be directly used for modeling of the WCDMA interface in the UMTS network servicing different traffic classes with and without compression. The described model can be applied for a validation of the efficiency of the WCDMA interface measured by the blocking probability and the average carried traffic for particular traffic classes.
The author describes a number of configurations and disk scheduling algorithms for shadow sets, and presents an analysis of seek time based on both a simulation and an analytic model. She focuses on the algorithm base...
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The author describes a number of configurations and disk scheduling algorithms for shadow sets, and presents an analysis of seek time based on both a simulation and an analytic model. She focuses on the algorithm based on assigning a read request to the arm that is within the shortest seek distance of the target location. With this scheduling algorithm, shadowing five disks decreases the expected seek time for reads by 50%. For a ratio of reads to writes equal to 1.5 or higher, shadowing decreases the overall seek time by 20%.< >
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