The Experts below are selected from a list of 2400 Experts worldwide ranked by ideXlab platform

William K Wong - One of the best experts on this subject based on the ideXlab platform.

  • Fairness assessment of the adaptive token bank Fair Queuing scheduling algorithm
    Vehicular Technology Conference, 2008
    Co-Authors: F A Bokhari, William K Wong, Halim Yanikomeroglu, Mahmudur Rahman
    Abstract:

    Adaptive token bank Fair Queuing (ATBFQ) algorithm has been proposed as a cross-layer scheduling technique for 4G wireless systems recently. This algorithm takes higher layer quality of service (QoS) attributes such as priorities, interflow Fairness, and delay constraints into account. By selecting the user terminals (UTs) in a certain prioritized manner derived from QoS attributes, the performance of the UTs, suffering from high interference and/or shadowing in particular, can be improved. The ATBFQ algorithm has been tested in a multicell environment in the presence of intercell interference by comparing with reference Score Based (SB) and Round Robin (RR) algorithms. In this paper, we further analyze ATBFQ primarily with regard to Fairness along with other performance metrics accessed in a more elaborate system considering varying interference and loading conditions. Furthermore, an adaptive method for the allocation of resources is proposed for ATBFQ parameter selection, and is shown to have better performance in various loading conditions. It is observed from simulation results that ATBFQ with adaptive parameter selection outperforms the reference schemes in terms of Queuing delay and UT throughput for different network loading cases.

  • token bank Fair Queuing a new scheduling algorithm for wireless multimedia services
    International Journal of Communication Systems, 2004
    Co-Authors: William K Wong, Helen Tang, Victor C M Leung
    Abstract:

    SUMMARY The token bank Fair Queuing algorithm (TBFQ) is a novel scheduling algorithm that is suitable for wireless multimedia services. The bandwidth allocation mechanism integrates the leaky bucket structure with priority handling to address the problem of providing quality-of-service (QoS) guarantees to heterogeneous applications in the next generation packet-switched wireless networks. Scheduling algorithms are often tightly integrated with the wireless medium access control (MAC) protocol. However, when heterogeneous wireless systems need to be integrated and interoperate with each other, it is desirable from the QoS provisioning standpoint to decouple scheduling algorithm from the MAC protocol. In this paper we propose a framework of seamless QoS provisioning and the application of TBFQ for uplink and downlink scheduling in wireless networks. We study its performance under a generic medium access framework that enables the algorithm to be generalized to provide QoS guarantees under various medium access schemes. We give a brief analysis of the algorithm and compare its performance with common scheduling algorithms through simulation. Our results demonstrate that TBFQ significantly increases wireless channel utilization while maintaining the same QoS, unlike many Fair Queuing algorithms, TBFQ does not require timestamping information of each packet arrival}an impractical feature in an already resource scarce environment. This makes TBFQ suitable for wireless multimedia communication. Copyright # 2004 John Wiley & Sons, Ltd.

  • token bank Fair Queuing a new scheduling algorithm for wireless multimedia services research articles
    International Journal of Communication Systems, 2004
    Co-Authors: William K Wong, Helen Tang, Victor C M Leung
    Abstract:

    The token bank Fair Queuing algorithm (TBFQ) is a novel scheduling algorithm that is suitable for wireless multimedia services. The bandwidth allocation mechanism integrates the leaky bucket structure with priority handling to address the problem of providing quality-of-service (QoS) guarantees to heterogeneous applications in the next generation packet-switched wireless networks. Scheduling algorithms are often tightly integrated with the wireless medium access control (MAC) protocol. However, when heterogeneous wireless systems need to be integrated and interoperate with each other, it is desirable from the QoS provisioning standpoint to decouple scheduling algorithm from the MAC protocol. In this paper we propose a framework of seamless QoS provisioning and the application of TBFQ for uplink and downlink scheduling in wireless networks. We study its performance under a generic medium access framework that enables the algorithm to be generalized to provide QoS guarantees under various medium access schemes. We give a brief analysis of the algorithm and compare its performance with common scheduling algorithms through simulation. Our results demonstrate that TBFQ significantly increases wireless channel utilization while maintaining the same QoS, unlike many Fair Queuing algorithms, TBFQ does not require time-stamping information of each packet arrival—an impractical feature in an already resource scarce environment. This makes TBFQ suitable for wireless multimedia communication. Copyright © 2004 John Wiley & Sons, Ltd.

  • soft qos provisioning using the token bank Fair Queuing scheduling algorithm
    IEEE Wireless Communications, 2003
    Co-Authors: William K Wong, Haiying Zhu, Victor C M Leung
    Abstract:

    Future-generation wireless packet networks will support multimedia applications with diverse QoS requirements. Much of the research on scheduling algorithms has been focused on hard QoS provisioning of integrated services. Although these algorithms give hard delay bounds, their stringent requirements sacrifice the potential statistical multiplexing performance and flexibility of the packet-switched network. Furthermore, the complexities of the algorithms often make them impractical for wireless networks. There is a need to develop a packet scheduling scheme for wireless packet-switched networks that provides soft QoS guarantees for heterogeneous traffic, and is also simple to implement and manage. This article proposes token bank Fair Queuing (TBFQ), a soft scheduling algorithm that possesses these qualities. This algorithm is work-conserving and has a complexity of O(1). We focus on packet scheduling on a reservation-based TDMA/TDD wireless channel to service integrated real-time traffic. The TBFQ scheduling mechanism integrates the policing and servicing functions, and keeps track of the usage of each connection. We address the impact of TBFQ on mean packet delay, violation probability, and bandwidth utilization. We also demonstrate that due to its soft provisioning capabilities, the TBFQ performs rather well even when traffic conditions deviate from the established contracts.

Victor C M Leung - One of the best experts on this subject based on the ideXlab platform.

  • token bank Fair Queuing a new scheduling algorithm for wireless multimedia services
    International Journal of Communication Systems, 2004
    Co-Authors: William K Wong, Helen Tang, Victor C M Leung
    Abstract:

    SUMMARY The token bank Fair Queuing algorithm (TBFQ) is a novel scheduling algorithm that is suitable for wireless multimedia services. The bandwidth allocation mechanism integrates the leaky bucket structure with priority handling to address the problem of providing quality-of-service (QoS) guarantees to heterogeneous applications in the next generation packet-switched wireless networks. Scheduling algorithms are often tightly integrated with the wireless medium access control (MAC) protocol. However, when heterogeneous wireless systems need to be integrated and interoperate with each other, it is desirable from the QoS provisioning standpoint to decouple scheduling algorithm from the MAC protocol. In this paper we propose a framework of seamless QoS provisioning and the application of TBFQ for uplink and downlink scheduling in wireless networks. We study its performance under a generic medium access framework that enables the algorithm to be generalized to provide QoS guarantees under various medium access schemes. We give a brief analysis of the algorithm and compare its performance with common scheduling algorithms through simulation. Our results demonstrate that TBFQ significantly increases wireless channel utilization while maintaining the same QoS, unlike many Fair Queuing algorithms, TBFQ does not require timestamping information of each packet arrival}an impractical feature in an already resource scarce environment. This makes TBFQ suitable for wireless multimedia communication. Copyright # 2004 John Wiley & Sons, Ltd.

  • token bank Fair Queuing a new scheduling algorithm for wireless multimedia services research articles
    International Journal of Communication Systems, 2004
    Co-Authors: William K Wong, Helen Tang, Victor C M Leung
    Abstract:

    The token bank Fair Queuing algorithm (TBFQ) is a novel scheduling algorithm that is suitable for wireless multimedia services. The bandwidth allocation mechanism integrates the leaky bucket structure with priority handling to address the problem of providing quality-of-service (QoS) guarantees to heterogeneous applications in the next generation packet-switched wireless networks. Scheduling algorithms are often tightly integrated with the wireless medium access control (MAC) protocol. However, when heterogeneous wireless systems need to be integrated and interoperate with each other, it is desirable from the QoS provisioning standpoint to decouple scheduling algorithm from the MAC protocol. In this paper we propose a framework of seamless QoS provisioning and the application of TBFQ for uplink and downlink scheduling in wireless networks. We study its performance under a generic medium access framework that enables the algorithm to be generalized to provide QoS guarantees under various medium access schemes. We give a brief analysis of the algorithm and compare its performance with common scheduling algorithms through simulation. Our results demonstrate that TBFQ significantly increases wireless channel utilization while maintaining the same QoS, unlike many Fair Queuing algorithms, TBFQ does not require time-stamping information of each packet arrival—an impractical feature in an already resource scarce environment. This makes TBFQ suitable for wireless multimedia communication. Copyright © 2004 John Wiley & Sons, Ltd.

  • soft qos provisioning using the token bank Fair Queuing scheduling algorithm
    IEEE Wireless Communications, 2003
    Co-Authors: William K Wong, Haiying Zhu, Victor C M Leung
    Abstract:

    Future-generation wireless packet networks will support multimedia applications with diverse QoS requirements. Much of the research on scheduling algorithms has been focused on hard QoS provisioning of integrated services. Although these algorithms give hard delay bounds, their stringent requirements sacrifice the potential statistical multiplexing performance and flexibility of the packet-switched network. Furthermore, the complexities of the algorithms often make them impractical for wireless networks. There is a need to develop a packet scheduling scheme for wireless packet-switched networks that provides soft QoS guarantees for heterogeneous traffic, and is also simple to implement and manage. This article proposes token bank Fair Queuing (TBFQ), a soft scheduling algorithm that possesses these qualities. This algorithm is work-conserving and has a complexity of O(1). We focus on packet scheduling on a reservation-based TDMA/TDD wireless channel to service integrated real-time traffic. The TBFQ scheduling mechanism integrates the policing and servicing functions, and keeps track of the usage of each connection. We address the impact of TBFQ on mean packet delay, violation probability, and bandwidth utilization. We also demonstrate that due to its soft provisioning capabilities, the TBFQ performs rather well even when traffic conditions deviate from the established contracts.

Meng Chang Chen - One of the best experts on this subject based on the ideXlab platform.

  • 1 Inter-Frame Space (IFS)-based Distributed Fair Queuing for Proportional Fairness in IEEE 802.11 WLANs
    2015
    Co-Authors: Jengfarn Lee, Wanjiun Liao, Meng Chang Chen
    Abstract:

    mechanism to provide proportional Fairness service for IEEE 802.11 WLANs. IDFQ is designed to emulate Self-Clocked Fair Queuing (SCFQ) in a distributed manner. It eliminates the backoff process as implemented in existing work and introduces a new mechanism to assign the inter-frame space to each station. IDFQ is immune from the implementation problem suffered by existing IFS-based mechanisms and is adaptive to the collision state in the system. Moreover, it can be used to eliminate the performance anomaly problem with 802.11 MAC. The performance of IDFQ is validated by ns-2 simulations. Simulation results show that IDFQ supports Fairness service for flows in proportion to their weights, and outperforms existing mechanisms in terms of Fairness and stability, rendering IDFQ an excellent candidate to provide weighted Fairness in IEEE 802.11 WLANs.

  • interframe space ifs based distributed Fair Queuing for proportional Fairness in ieee 802 11 wlans
    IEEE Transactions on Vehicular Technology, 2007
    Co-Authors: Jengfarn Lee, Wanjiun Liao, Meng Chang Chen
    Abstract:

    In this paper, we propose an interframe-space (IFS)-based distributed-Fair-Queuing (IDFQ) mechanism to provide proportional Fairness service for IEEE 802.11 wireless local-area networks (WLANs). IDFQ is designed to emulate self-clocked Fair Queuing in a distributed manner. It eliminates the backoff process as implemented in existing work and introduces a new mechanism to assign the IFS value to each station. IDFQ is immune from the implementation problem suffered by existing IFS-based mechanisms and is adaptive to the collision state in the system. Moreover, it can be used to eliminate the performance-anomaly problem of 802.11 medium-access control. The performance of IDFQ is validated by ns-2 simulations. The simulation results show that IDFQ supports Fairness service for flows in proportion to their weights and outperforms existing mechanisms in terms of Fairness and stability, rendering IDFQ an excellent candidate to provide weighted Fairness in IEEE 802.11 WLANs

  • inter frame space ifs based distributed Fair Queuing in ieee 802 11 wlans
    Broadband Communications Networks and Systems, 2005
    Co-Authors: Jengfarn Lee, Wanjiun Liao, Meng Chang Chen
    Abstract:

    In this paper, we study Fair Queuing in the MAC layer of IEEE 802.11 with the distributed coordination function (DCF). In particular, we propose an IFS-based distributed Fair Queuing (IDFQ) mechanism to provide differentiated service in conformance with the 802.11 standard. IDFQ is designed to emulate self-clocked Fair Queuing (SCFQ) in a distributed manner. There is no backoff in IDFQ. Thus, it provides better stability and improved aggregate throughput, as compared to existing work. Simulation results show that IDFQ supports differentiated service for different flows in proportion to their weights. More importantly, it outperforms existing solutions in terms of Fairness and stability, rendering IDFQ an excellent candidate to provide weighted Fairness for IEEE 802.11 WLANs.

Ying Zhao - One of the best experts on this subject based on the ideXlab platform.

  • a weighted Fair Queuing wfq based dynamic request scheduling approach in a multi core system
    Future Generation Computer Systems, 2012
    Co-Authors: Guohua You, Ying Zhao
    Abstract:

    A popular website is expected to simultaneously deal with a large number of dynamic requests in the reasonable mean response time. The performance of websites mainly depends on hardware performance and the processing strategy of dynamic requests. In order to improve the hardware performance, more and more web servers are adopting multi-core CPUs. Moreover, the scheduling algorithm of requests on the first-come-first-served (FCFS) basis is still utilized. Although FCFS is a reasonable and Fair strategy for request sequences, it takes into account neither the distribution of the dynamic request service times nor the characteristics of multi-core CPUs. In the present paper, in order to solve the above-mentioned problems, a new dynamic request scheduling approach is proposed. The new scheduling approach, according to the distribution of the dynamic request service time, schedules the dynamic requests based on a weighted-Fair-Queuing (WFQ) system, and exploits the performance of multi-core CPUs by means of the hard affinity method in the O/S. Simulation experiments have been done to evaluate the new scheduling approach, and the results obtained prove that the new scheduling approach could eliminate the ping-pong effect and efficiently reduce the mean response time.

Jengfarn Lee - One of the best experts on this subject based on the ideXlab platform.

  • 1 Inter-Frame Space (IFS)-based Distributed Fair Queuing for Proportional Fairness in IEEE 802.11 WLANs
    2015
    Co-Authors: Jengfarn Lee, Wanjiun Liao, Meng Chang Chen
    Abstract:

    mechanism to provide proportional Fairness service for IEEE 802.11 WLANs. IDFQ is designed to emulate Self-Clocked Fair Queuing (SCFQ) in a distributed manner. It eliminates the backoff process as implemented in existing work and introduces a new mechanism to assign the inter-frame space to each station. IDFQ is immune from the implementation problem suffered by existing IFS-based mechanisms and is adaptive to the collision state in the system. Moreover, it can be used to eliminate the performance anomaly problem with 802.11 MAC. The performance of IDFQ is validated by ns-2 simulations. Simulation results show that IDFQ supports Fairness service for flows in proportion to their weights, and outperforms existing mechanisms in terms of Fairness and stability, rendering IDFQ an excellent candidate to provide weighted Fairness in IEEE 802.11 WLANs.

  • interframe space ifs based distributed Fair Queuing for proportional Fairness in ieee 802 11 wlans
    IEEE Transactions on Vehicular Technology, 2007
    Co-Authors: Jengfarn Lee, Wanjiun Liao, Meng Chang Chen
    Abstract:

    In this paper, we propose an interframe-space (IFS)-based distributed-Fair-Queuing (IDFQ) mechanism to provide proportional Fairness service for IEEE 802.11 wireless local-area networks (WLANs). IDFQ is designed to emulate self-clocked Fair Queuing in a distributed manner. It eliminates the backoff process as implemented in existing work and introduces a new mechanism to assign the IFS value to each station. IDFQ is immune from the implementation problem suffered by existing IFS-based mechanisms and is adaptive to the collision state in the system. Moreover, it can be used to eliminate the performance-anomaly problem of 802.11 medium-access control. The performance of IDFQ is validated by ns-2 simulations. The simulation results show that IDFQ supports Fairness service for flows in proportion to their weights and outperforms existing mechanisms in terms of Fairness and stability, rendering IDFQ an excellent candidate to provide weighted Fairness in IEEE 802.11 WLANs

  • inter frame space ifs based distributed Fair Queuing in ieee 802 11 wlans
    Broadband Communications Networks and Systems, 2005
    Co-Authors: Jengfarn Lee, Wanjiun Liao, Meng Chang Chen
    Abstract:

    In this paper, we study Fair Queuing in the MAC layer of IEEE 802.11 with the distributed coordination function (DCF). In particular, we propose an IFS-based distributed Fair Queuing (IDFQ) mechanism to provide differentiated service in conformance with the 802.11 standard. IDFQ is designed to emulate self-clocked Fair Queuing (SCFQ) in a distributed manner. There is no backoff in IDFQ. Thus, it provides better stability and improved aggregate throughput, as compared to existing work. Simulation results show that IDFQ supports differentiated service for different flows in proportion to their weights. More importantly, it outperforms existing solutions in terms of Fairness and stability, rendering IDFQ an excellent candidate to provide weighted Fairness for IEEE 802.11 WLANs.