Hai-tao Zhao

Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu Sheng, China

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Publications (8)0.65 Total impact

  • Zai-jian Wang · Yu-ning Dong · Hui Zhang · Hai-tao Zhao
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    ABSTRACT: To increase the end-to-end system efficiency with a flexible QoS (Quality of Service) class mapping scheme for transporting multimedia traffic over heterogeneous networks, by analyzing current QoS class mapping schemes which lack flexibility without considering user's QoE (Quality of Experience), an analytical model is developed for end-to-end QoS provisioning based on network calculus theory. Based on this model, the paper derives an Elastic QoS Class Mapping Method (EQCMM) which considers user's QoE. With EQCMM, the result of QoS class mapping can be adjusted elastically according to available network resources, in order to achieve higher end-to-end system efficiency. Finally, simulation results are given to demonstrate the effectiveness of the proposed method.
    No preview · Article · Mar 2014 · Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology
  • Hai-tao Zhao · Yu-ning Dong · Hui Zhang · Yang Li
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    ABSTRACT: In this paper, we develop a link quality-based adaptive adjustment mechanism of the MAC maximum retransmission count to reduce collision probability of wireless Mesh networks. Based on statistics acquired in the link layer and the retransmission strategy, a multi-metric cross-layer on-demand routing scheme is proposed for wireless Mesh networks. The proposed scheme uses information such as available link bandwidth, node residual load rate and transmission efficiency of a path adequately to cross-layer routing. The network layer can adaptively select an optimal path to deliver packets based on the acquired statistics of the MAC layer. Extensive simulation results demonstrate that the proposed scheme can reduce link failure probability, improve network throughput, and decrease the end-to-end delay effectively. KeywordsWireless mesh networks–IEEE802.11 DCF–Cross-layer routing design–Link quality
    No preview · Article · Mar 2012 · Wireless Personal Communications
  • Wang Zai-jian · Yu-ning Dong · Hai-tao Zhao · Fang ShuGuang
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    ABSTRACT: To provide better flow services over wireless networks, a QoS (Quality of Service) mapping scheme based on flow aggregate (QMS-FAG) is proposed in this paper. The proposed scheme makes QoS mapping between intermediate networks transparent, and can utilize the network resources more efficiently. In this scheme, the QoS class of the destination network decided by the QoS requirements of the source network, so as to assure the end-to-end QoS of multimedia services in wireless networks. Simulation results demonstrate the efficacy of the proposed scheme.
    No preview · Conference Paper · Jan 2012
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    ABSTRACT: A model-based channel capacity prediction scheme is proposed to provide statistical quality-of-service (QoS) guarantees under a medium or high traffic load for IEEE 802.11 based wireless multimedia networks. The proposed scheme perceives the state of wireless link from the MAC retransmission information and calculates the statistical channel capacity especially in saturated traffic load. Based on the capacity prediction model, resource reservation and QoS routing optimization are carried out. Via a cross-layer design approach, the scheme allocates network resource and forwards data packet by taking into consideration of the interference among flows and the link state. Simulation results show that the proposed scheme can achieve more accurate capacity prediction and higher resource utilization than previous QoS routing schemes, and improve network performance in terms of end to end transmission delay, packet delivery ratio and network throughput.
    No preview · Article · Nov 2011
  • Xinxing Zhao · Yuning Dong · Hai-tao Zhao · Zhang Hui · Jiazhou Li · Can Sheng
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    ABSTRACT: In this paper, we first investigate the performance of the 3G WCDMA wireless channel, and we find a special character, that sometimes a sudden link blockage/ congestion happens and causes heavy throughput drops during a certain time in the given 3G channel. After getting the basic characteristics and information about the performance, a novel transmission control scheme is proposed based on the Gilbert wireless error model by analysis of the characteristics which we notice of the wireless channel. The proposed scheme takes into consideration of the link blockage/sudden congestion which last for a short time in the 3G networks, the packet loss rate, and congestion level to increase packet successful delivery rate, reduce congestion and to improve the overall performance in the 3G networks by a adjustable rate control mechanism. Extensive simulation results demonstrate that the proposed scheme is effective in rate control and in decreasing the congestion level.
    No preview · Article · Nov 2010
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    ABSTRACT: Cognitive radio is a dynamic spectrum access technology as a solution to spectrum under-utilization problem in some licensed bands. Cognitive radio should sense the spectrum usage steadily to prevent interfering licensed users and spectrum occupancy information of licensed users can be used both for learning the usage and prediction of the future occupancy. In this paper, a two-state high-order Markov chain based prediction model is presented for cognitive radio system to predict spectrum occupancy. This model adopts an improved LZ78 algorithm to evaluate transition probabilities of the two-state high-order Markov chain. Simulation results show that the proposed scheme can predict spectrum usage effectively and significantly reduce computational cost compared to prediction algorithms based on AR model.
    No preview · Conference Paper · Jun 2010
  • Hai-tao Zhao · Yu-ning Dong · Yang Li
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    ABSTRACT: As the rapid growth of wireless IP networks, wireless IP access networks have a lot of potential applications in a variety of fields in civilian and military environments. Many of these applications, such as realtime audio/video streaming, will require some form of end-to-end QoS assurance. In this paper, an algorithm WMPLD (Wireless Multimedia Packet Loss Discrimination) is proposed for multimedia transmission control over wired-wireless hybrid IP networks. The relationship between packet length and packet loss rate in the Gilbert wireless error model is investigated. Furthermore, the algorithm can detect the nature of packet losses by sending large and small packets alternately, and control the sending rate of nodes. In addition, by means of updating factor K, this algorithm can adapt to the changes of network states quickly. Simulation results show that, compared to previous algorithms, WMPLD algorithm can improve the networks throughput as well as reduce the congestion loss rate in various situations. KeywordsWireless IP networks-Congestion control-Wireless loss-Quality of Service
    No preview · Chapter · Dec 2009
  • Hai-tao Zhao · Yu-ning Dong · Yang Li
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    ABSTRACT: In this paper, we propose an algorithm WMTA (wireless multimedia transmission algorithm) for multimedia transmission control over wireless-wired IP networks. The relationship between packet length and packet loss rate over the Markov wireless error model is investigated. Based on this character, the algorithm can detect the nature of packet losses by sending large and small packets alternately, and control the sending rate of nodes. Furthermore, by use of an updating factor K, the algorithm can adapt to the changes of network states quickly. Extensive computer simulations demonstrate that the proposed scheme is effective in satisfying the end to end quality of service and reducing the congestion loss rate in various network topologies.
    No preview · Conference Paper · Oct 2009