Transmitting delay-sensitive video streaming over IEEE 802.11e wireless local area networks (WLANs) is becoming increasingly popular. However, the transmission of real-time video streaming is very challenging because ...
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Transmitting delay-sensitive video streaming over IEEE 802.11e wireless local area networks (WLANs) is becoming increasingly popular. However, the transmission of real-time video streaming is very challenging because of the time-varying wireless channels and video content characteristics. The authors propose an accurate model to assess the perceived quality of video streaming over WLANs with enhanced distributed coordination function (EDCF) mechanism. The analytical model considers not only the packet loss caused by wireless interference and channel fading, but also the effects of loss from channel access competition. Based on the Markov chain, the authors then present the discrete probability distribution of medium access control (MAC) layer packet service time by using the signal transfer function of the generalised state transition diagram. Moreover, the coding relation of lost video frames is also explored in the performance analysis of the proposed model. Simulations based on Network Simulator 2 (NS-2) are conducted to verify the performance of the analytical model. The results show that the proposed model provides superior accuracy for the perceived quality of MPEG-4 video streaming over IEEE 802.11e EDCF-based WLANs.
This paper presents a simulation-based study of a MAC protocol, named Contention Free Bursting (also referred to as enhanced distributed coordination function (EDCF) Bursting) described as an optional mode of operatio...
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ISBN:
(纸本)0780389662
This paper presents a simulation-based study of a MAC protocol, named Contention Free Bursting (also referred to as enhanced distributed coordination function (EDCF) Bursting) described as an optional mode of operation in 802.11e WLAN networks. A simple recovery mechanism is proposed upon transmission failure during the burst. The new scheme aims to provide better Quality of Service when high throughput applications operate in the presence of low throughput, latency-sensitive applications.
This article introduces the emerging IEEE 802.11e standard to support quality of service at the medium access control layer. Both the contention-based and contention-free centrally controlled channel access mechanisms...
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This article introduces the emerging IEEE 802.11e standard to support quality of service at the medium access control layer. Both the contention-based and contention-free centrally controlled channel access mechanisms are introduced by describing not only the MAC protocol operations and parameters, but also the call admission techniques and scheduling algorithm that have been designed for IEEE 802.11e. Finally, we provide simulation results aimed to highlight the capability of the EDCF to differentiate the traffic classes.
Medium access represents one of the most critical building blocks regarding the performance of a wireless LAN. In this letter, we compare the performance of two well-known medium access control protocols specifically ...
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Medium access represents one of the most critical building blocks regarding the performance of a wireless LAN. In this letter, we compare the performance of two well-known medium access control protocols specifically developed for the wireless environment, EDCF and EY-NPMA. To our knowledge, it is the first time that these two quality-of-service (QoS) aware medium access schemes are compared. Furthermore, we propose a novel scheme for medium access based on EY-NPMA, that demonstrates reduced overhead compared to the base protocol and better utilization of the common medium. The conclusions of this paper are based on extensive simulation trials.
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