• Title, Summary, Keyword: priority scheme

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Total Resource Requirements-Based Priority Queuing Scheme for DS/CDMA Cellular Networks

  • Piao, Shiquan;Park, Jae-Won;Park, Yong-Wan
    • ETRI Journal
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    • v.28 no.3
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    • pp.371-374
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    • 2006
  • We propose and analyze a priority queuing scheme that gives priority in the same class of calls according to their total resource requirements (TRRs). The proposed scheme gives a higher priority to the calls that have a lower TRR over the calls that have a higher TRR. The numerical results show that the proposed priority queuing scheme provides better performance than the traditional queuing schemes in call blocking probability.

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Performance Modelling of Adaptive VANET with Enhanced Priority Scheme

  • Lim, Joanne Mun-Yee;Chang, YoongChoon;Alias, MohamadYusoff;Loo, Jonathan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.4
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    • pp.1337-1358
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    • 2015
  • In this paper, we present an analytical and simulated study on the performance of adaptive vehicular ad hoc networks (VANET) priority based on Transmission Distance Reliability Range (TDRR) and data type. VANET topology changes rapidly due to its inherent nature of high mobility nodes and unpredictable environments. Therefore, nodes in VANET must be able to adapt to the ever changing environment and optimize parameters to enhance performance. However, there is a lack of adaptability in the current VANET scheme. Existing VANET IEEE802.11p's Enhanced Distributed Channel Access; EDCA assigns priority solely based on data type. In this paper, we propose a new priority scheme which utilizes Markov model to perform TDRR prediction and assign priorities based on the proposed Markov TDRR Prediction with Enhanced Priority VANET Scheme (MarPVS). Subsequently, we performed an analytical study on MarPVS performance modeling. In particular, considering five different priority levels defined in MarPVS, we derived the probability of successful transmission, the number of low priority messages in back off process and concurrent low priority transmission. Finally, the results are used to derive the average transmission delay for data types defined in MarPVS. Numerical results are provided along with simulation results which confirm the accuracy of the proposed analysis. Simulation results demonstrate that the proposed MarPVS results in lower transmission latency and higher packet success rate in comparison with the default IEEE802.11p scheme and greedy scheduler scheme.

Hop-by-Hop Priority Increasing Scheme for Improving End-to-end Throughput in Multi-Hop OBS Networks (다중 홉 광 버스트 교환망에서 종단간 수율 향상을 위한 홉 단위 우선 순위 증가 기법)

  • 김병철;조유제
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.10
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    • pp.35-42
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    • 2003
  • In this paper, we classified the wavelength reservation mechanisms of optical burst switching (OBS), and investigated the path length priority effect of the offset time/delayed reservation (OT/DR)-based scheme like the just-enough-time (JET) protocol. And, we showed that the fiber delay line (FDL)-based scheme can avoid the path length priority effect in multiple hop network environments. Also, we proposed a novel FDL/DR with hop-by-hop priority increasing (HPI) scheme which can improve the end-to-end throughput by increasing the priority of bursts hop-by-hop using the input FDLs at each node. The simulation results showed that the proposed FDL/DR with HPI scheme could avoid the path length priority effect and enhance the end-to-end throughput in multiple hop network environments.

A Study on Buffer Processing using Push Out Scheme with Variable Threshold (가변 임계값을 갖는 푸쉬 아웃 기법을 이용한 트래픽 제어)

  • 최인수;박호균;류황빈
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.12
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    • pp.1884-1892
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    • 1993
  • In push out scheme, high priority cell which arrives when the buffer is full pushs low priority cell. The PBS scheme provides priority by variable threshold in buffer.In this paper, for Controlling congestion in ATM network we propose buffer processing method in which the PBS scheme has variable threshold. And we analysis The performance of this scheme. As a result of simulation, the proposed push out scheme with variable threshold reduces the loss of low priority cell compared with existing push out scheme. This proposed method not only reduces the loss of high priority cell like existing push out scheme but also reduces the loss of low priority cell by variable threshold.

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Delay Performance of Multi-Service Network with Strict Priority Scheduling Scheme

  • Lee, Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.2B
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    • pp.11-20
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    • 2005
  • Strict priority scheduling scheme is a good candidate for the implementation of service differentiation in an Internet because of simplicity in implementation and the capability to guarantee the delay requirement of the highest class of traffic. However, it is also blown that strict priority starves the lower-class traffic at the cost of prioritizing the higher-class traffic. The purpose of this work is to propose an analytic method which can estimate the average delay performance of Diffserv service architecture and shows that strict priority scheme does not sacrifice the lower class traffic over a diverse condition of the load. From the numerical experiments for three-class Diffserv network we validate our argument that strict priority scheme may be applied to a service differentiation scheme for the future Internet.

Enhancing Fixed Priority Scheduling Algorithms for Real-Time Tasks on Multiprocessors (다중처리기 상의 실시간 태스크를 위한 고정 우선순위 스케줄링 알고리즘의 성능 향상)

  • Park Minkyu;Han Sangchul;Kim HeeHeon;Cho Seongje;Cho Yookun
    • Journal of KIISE:Computing Practices and Letters
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    • v.11 no.1
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    • pp.62-68
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    • 2005
  • This paper presents a scheme to enhance fixed priority scheduling algorithms on multiprocessors. This scheme gives the highest priority to jobs with zero laxity and schedules them Prior to other jobs. A fixed priority algorithm employing this scheme strictly dominates the original one; it can schedule all task sets schedulable by the fixed priority algorithm and some task sets not schedulable by the fixed priority algorithm. Simulation results show that the proposed scheme improves fixed priority algorithms in terms of the number of schedulable task sets and schedulable utilization bound.

An Efficient Priority Based Adaptive QoS Traffic Control Scheme for Wireless Access Networks

  • Kang Moon-sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.9A
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    • pp.762-771
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    • 2005
  • In this paper, an efficient Adaptive quality-of-service (QoS) traffic control scheme with priority scheduling is proposed for the multimedia traffic transmission over wireless access networks. The objective of the proposed adaptive QoS control (AQC) scheme is to realize end-to-end QoS, to be scalable without the excess signaling process, and to adapt dynamically to the network traffic state according to traffic flow characteristics. Here, the reservation scheme can be used over the wireless access network in order to get the per-flow guarantees necessary for implementation of some kinds of multimedia applications. The AQC model is based on both differentiated service model with different lier hop behaviors and priority scheduling one. It consists of several various routers, access points, and bandwidth broker and adopts the IEEE 802.1 le wireless radio technique for wireless access interface. The AQC scheme includes queue management and packet scheduler to transmit class-based packets with different per hop behaviors (PHBs). Simulation results demonstrate effectiveness of the proposed AQC scheme.

Priority-Based Network Interrupt Scheduling for Predictable Real-Time Support

  • Lee, Minsub;Kim, Hyosu;Shin, Insik
    • Journal of Computing Science and Engineering
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    • v.9 no.2
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    • pp.108-117
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    • 2015
  • Interrupt handling is generally separated from process scheduling. This can lead to a scheduling anomaly and priority inversion. The processor can interrupt a higher priority process that is currently executing, in order to handle a network packet reception interruption on behalf of its intended lower priority receiver process. We propose a new network interrupt handling scheme that combines interrupt handling with process scheduling and the priority of the process. The proposed scheme employs techniques to identify the intended receiver process of an incoming packet at an earlier phase. We implement a prototype system of the proposed scheme on Linux 2.6, and our experiment results show that the prototype system supports the predictable real-time behavior of higher priority processes even when excessive traffic is sent to lower priority processes.

A Priority Scheme for IEEE 802.11 Wireless LAN

  • Jang, Yeong-Min
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.12B
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    • pp.1996-2002
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    • 2000
  • This paper investigates a priority scheme for IEEE 802.11 Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) protocol in order to provide short access times for priority frames (e.g. time-deadline traffic) even when the overall traffic on the wireless channel is heavy. Under the compatibility constraint for the IEEE 802.11 wireless LANs, two priority systems are simulated: no priority (current IEEE 802.11 standard) for time-deadline traffics and dynamic time-deadline priority. We evaluate algorithms to improve the time-deadline traffic performance using discrete event simulation (DES)

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Priority-based Unequal Error Protection Scheme of Data partitioned H.264 video with Hierarchical QAM

  • Chen, Rui;Wu, Minghu;Yang, Jie;Rui, Xiongli
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.11
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    • pp.4189-4202
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    • 2014
  • In this paper, we propose a priority-based unequal error protection scheme of data partitioned H.264/AVC video with hierarchical quadrature amplitude modulation. In order to map data with higher priority onto the most significant bits of QAM constellation points, a priority sorting method categorizes different data partitions according to the unequal importance factor of encoded video data in one group of pictures by evaluated the average distortion. Then we propose a hierarchical quadrature amplitude modulation arrangement with adaptive constellation distances, which takes into account the unequal importance of encoded video data and the channel status. Simulation results show that the proposed scheme improves the received video quality by about 2 dB in PSNR comparing with the state-of-the-art unequal error protection scheme, and outperforms EEP scheme by up to 5 dB when the average channel SNR is low.