Conference Paper

VQ-RED: An efficient virtual queue management approach to improve fairness in infrastructure WLAN

Dept. of Comput. Sci., Hong Kong Univ. of Sci. & Technol., Kowloon, China;
DOI: 10.1109/LCN.2005.136 Conference: Local Computer Networks, 2005. 30th Anniversary. The IEEE Conference on
Source: IEEE Xplore

ABSTRACT In this paper, we consider two fairness problems (downlink/uplink fairness and fairness among flows in the same direction) that arise in the infrastructure WLAN. We propose a virtual queue management approach, named VQ-RED to address the fairness problems. We demonstrate the effectiveness of our approach by conducting a series of simulations. The results show that compared with standard DCF, VQRED not only greatly improves the fairness, but also reduces packet delays.

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    ABSTRACT: We propose an active buffer management scheme to guarantee quality of service (QoS) for video streaming services in wireless local area network (WLAN). The proposed scheme uses the concept of virtual transmission delay and differentiates the frame drop policy according to the type of video frame. The virtual transmission delay is defined as the delay until the video frame is potentially transmitted since a frame is arrived at the buffer. By the simulation result, the frame transmission delay does not exceed the delay bound when the proposed scheme is used. As a result, the number of frames of degraded peak signal to noise ratio (PSNR) is reduced about 50% compared to the case that the conventional Enhanced Distributed Channel Access (EDCA) is used. The proposed protocol also outperforms the EDCA in the actually visual quality of video streaming.
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    ABSTRACT: Cross-layer interaction of Distributed Coordination Function (DCF) of 802.11 MAC protocol and TCP transport protocol leads to two types of unfairness. In a mixed traffic scenario, short-lived TCP flows suffer from poor performance compared to the aggressive long-lived flows. Since the main source of Internet traffic is small file web transfers, this issue forms a major challenge in current WLANs which is called size-based unfairness. In addition, when sharing an access point bottleneck queue, upstream flows impede the performance of downstream flows resulting in direction-based unfairness. Proposed solutions in the literature mostly rely on size-based scheduling policies. However, each proposed method is able to solve any of these two mentioned aspects, none of them can provide both size-based and direction-based fairness in a unique solution. In this paper, we propose a novel queue management policy called Threshold-Based Least Attained Service-Selective Acknowledgment Filtering (TLAS-SAF). We show analytically and by simulation that TLAS-SAF is capable of providing both direction-based and size-based fairness and can be taken into account as a unique solution to be applied at access point buffers.
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    ABSTRACT: In this paper the unfairness problems in wireless 802.11 LAN are researched and studied via simulation. The contributions are twofold. First of all, the intra-class fairness of the EDCA queues for downlink streams, in the presence of bidirectional traffic is investigated. Secondly, Active Queue Management schemes are evaluated as an possible improvement for the intra-class fairness. The simulation results show that some algorithms provide more equal share of wireless channel as well as the lower drop rate.

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Jun 2, 2014

Jogesh Muppala