In order to improve the spectrum utilization while providing a fairness guarantee between users under the dynamic spectrum resources, the optimization problem for the scheduler of OFDM system with an unlimited queue c...
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ISBN:
(纸本)9781479960224
In order to improve the spectrum utilization while providing a fairness guarantee between users under the dynamic spectrum resources, the optimization problem for the scheduler of OFDM system with an unlimited queue capacity in cognitive radio networks (CRN) is first formulated. Then, under the constraints of the optimization problem, the Genetic algorithm for Cognitive Radio Scheduler (GACRS) is proposed based on the Simple Genetic algorithm (SGA) to solve the optimization problem. Simulation results show that, by adjusting the proportion factor in the fitness function, GACRS algorithm can guarantee the fairness among users while reaching the upper limit of the spectrum utilization.
In this paper classic static and dynamic scheduling strategy is analyzed first, and then communication network of schedule ability judgment basis is given. An improved dynamic EDF scheduling algorithm is proposed in o...
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ISBN:
(纸本)9783037853122
In this paper classic static and dynamic scheduling strategy is analyzed first, and then communication network of schedule ability judgment basis is given. An improved dynamic EDF scheduling algorithm is proposed in order to improve the scheduling task of real-time. The scheduling strategy is to change task priority according to the transmission error over deadline task when applying dynamic EDF scheduling strategy. True Time tool is used to build CAN network control system simulation platform. Dynamic EDF scheduling algorithm and improved scheduling algorithm are simulated respectively. The effectiveness of improved scheduling algorithm is verified by the simulation
The LLF (Least Laxity First) scheduling algorithm assigns a priority to a task according to its executing urgency. The smaller the laxity value of a task is, the sooner it needs to be executed. However it leads to swi...
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ISBN:
(纸本)9781424413270
The LLF (Least Laxity First) scheduling algorithm assigns a priority to a task according to its executing urgency. The smaller the laxity value of a task is, the sooner it needs to be executed. However it leads to switch frequently among tasks, which causes the overhead of a system and restricts its application. The least switch and laxity first scheduling algorithm is proposed in the paper, which improves the least laxity first algorithm for periodic task by searching out an appropriate common divisor.
Anovel cross-layer scheduling algorithm with guaranteed QoS is proposed in CRN. A distinct scheduling priority integrating UCSI, QSI and QoS requirements is first ploposed for CUs. Base on these scheduling priorities ...
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ISBN:
(纸本)9781849192064
Anovel cross-layer scheduling algorithm with guaranteed QoS is proposed in CRN. A distinct scheduling priority integrating UCSI, QSI and QoS requirements is first ploposed for CUs. Base on these scheduling priorities and specific scheduling mechanism, packet scheduling and channel allocation are jointly designed. The simulation results reveal that the proposed algorithm suffers a limited decline in system throughput while reduces the packet delay and packet dropping probability effectively for cognitive users. By the optimized channel assignment with the Channel Allocation Weight, a better performance for spectral utility, packet delay and packet dropping probability is obtained under the dynamic UCSI in CRN.
The emergence of new data services in 3G networks is driving the support of advanced content-based billing mechanisms whose unique characteristics require that the OCS (Online Charging System) provide relative differe...
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ISBN:
(纸本)9781424423736
The emergence of new data services in 3G networks is driving the support of advanced content-based billing mechanisms whose unique characteristics require that the OCS (Online Charging System) provide relative differentiated services based on different contents. The OCS can be modeled by the PDD (Proportional Delay Differentiation) structure and it aims to maintain the prespecified mean system response-time delay ratios between different classes of requests. A novel request scheduling algorithm is proposed in this paper. The basic idea is that one of the requests from all classes of service queues is chosen with some priority probability which is based on the system queue-length, the request arrival rate, and the preassigned delay differentiation parameter. The experimental results show that this new algorithm significantly outperforms some other traditional PDD scheduling ones when request service delays increase and vary greatly from each other. Furthermore, it can efficiently meet 6 QoS requirements proposed in this paper.
This letter presents an efficient scheduling algorithm DTRR (Dual-Threshold Round Robin) for input-queued switches. In DTRR, a new matched input and output by round robin in a cell time will be locked by two self-adap...
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This letter presents an efficient scheduling algorithm DTRR (Dual-Threshold Round Robin) for input-queued switches. In DTRR, a new matched input and output by round robin in a cell time will be locked by two self-adaptive thresholds whenever the queue length or the wait-time of the head cell in the corresponding Virtual Output Queue (VOQ) exceeds the thresholds. The locked input and output will be matched directly in the succeeding cell time until they are unlocked. By employing queue length and wait-time thresholds which are updated every cell time simultane- ously, DTRR achieves a good tradeoff between the performance and hardware complexity. Simula- tion results indicate that the delay performance of DTRR is competitive compared to other typical scheduling algorithms under various traffic patterns especially under diagonal traffic.
Real-time systems have to complete the execution of a task within the predetermined time while ensuring that the execution results are logically correct. Such systems require scheduling methods that can adequately dis...
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ISBN:
(纸本)9780769539676
Real-time systems have to complete the execution of a task within the predetermined time while ensuring that the execution results are logically correct. Such systems require scheduling methods that can adequately distribute the given tasks to a processor. scheduling methods that all tasks can be executed within a predetermined deadline are called an optimal scheduling. In this paper, we propose a new and simple scheduling algorithm (LSTR: least slack time rate first) as a dynamic-priority algorithm for a multi-processor environment and demonstrate its optimal possibility through various tests.
Grid computing can integrate computational resources from different networks or regional areas into a high performance computational platform and be used to solve complex computing-intensive problems efficiently. Sche...
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ISBN:
(纸本)9780769533827
Grid computing can integrate computational resources from different networks or regional areas into a high performance computational platform and be used to solve complex computing-intensive problems efficiently. scheduling problem is an important issue in a grid computing environment, because of the heterogeneity of computing resources. This paper proposes an evolution-based dynamic scheduling algorithm (EDSA) for scheduling in grid computing environments. The proposed algorithm uses the genetic algorithm as search technique to find an efficient schedule in grid computing and adapts to variable numbers of computing nodes which has different computational capabilities. Furthermore, the hybrid crossover and incremental mutation operations within the algorithm can move the solution away from the local-optimal solution towards a near-optimal solution. And, a simulation with randomly generated task sets was performed to compare the performance with five other scheduling algorithms. The results show that the proposed EDSA outperformed all other schedulers across a range of scenarios.
In this paper we proposed a new dynamic scheduling algorithm for power scheduling problem. The algorithm is based on game theory and reinforcement learning approach. We compared the performance of our algorithm with t...
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ISBN:
(纸本)9783037851852
In this paper we proposed a new dynamic scheduling algorithm for power scheduling problem. The algorithm is based on game theory and reinforcement learning approach. We compared the performance of our algorithm with that of online bin packing and MAB algorithm. We observed that our algorithm performs better than online bin packing when there is a variation in the deadlines. This is because our algorithm schedules the requests on the basis of their actions and the probability of missing the deadline and online bin packing algorithm schedules requests based on the sequence of requests as they arrive. We observed that our approach is more useful, when scheduling requests repeat themselves for long duration.
Long Term Evolution (LTE) is the new generation wireless networks that support all IP transmission for multimedia services. One of the major challenges in LTE network is to provide the packet scheduling scheme that ca...
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ISBN:
(纸本)9781467367165
Long Term Evolution (LTE) is the new generation wireless networks that support all IP transmission for multimedia services. One of the major challenges in LTE network is to provide the packet scheduling scheme that can supports the Quality-of-Service (QoS) requirements of multimedia services. In this paper, a Quality-of-Service (QoS) aware packet scheduler for Real Time (RT) downlink communication in LTE is proposed. A Resource Block (RB) preserver scheduling algorithm that has two layers is developed. The upper layer exploits the LTE frame features of aggregating multiple numbers of sub-frames. The lower layer adopts the concept of Proportional Fair (PF) algorithm to schedule the Non Real Time (NRT) flows. While for the real time flows, the Exponential/Earliest Deadline (EXP/ED) algorithm is utilized. Our simulation results show the proposed Resource Block Preserver (RBP) algorithm outperforms both the Exponential/Proportional Fair (EXP/PF) and Maximum-Largest Weighted Delay First (M-LWDF) scheduling algorithms in terms of lower Packet Loss Ratio (PLR) among users in the downlink 3GPP LTE system supports VoIP services.
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