A Framework for Evaluation of Video Quality of Service in Wireless Networks

A Framework for Evaluation of Video Quality of Service in Wireless Networks

Dharm Singh (Namibia University of Science and Technology, Namibia) and Lal Chand Bishnoi (Uttrakhand Technical University, India)
DOI: 10.4018/978-1-5225-2342-0.ch001
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Abstract

Today's IEEE 802.11n WLAN are capable of delivering the essential bandwidth for video by using MPEG-4 or H.264 codec compression. However, 802.11n devices are popular for delivering wireless video transmission. Even though there are some challenges for these devices specifically severe network congestion that degrade the quality of video transmission. For assessing the video transmission quality during a simulation on 802.11n WLAN technology, we extended a framework and toolset (802.11nMyEvalVid) which can be used to measures the QoS constraints in wireless networks, such as throughput, delays, and end-to-end delay. However, it also supports PSNR, which is a received video quality measuring technique based on a comparison of frame-by-frame. This chapter focused on a framework 802.11nMyEvalVid that can be used for research and evaluating new techniques for MAC-layer optimizations for simulating MPEG-4, H.264/AVC and H.264/SVC video over 802.11n WLAN in a more efficient and reliable way.
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Qos On An Ip-Network

The services in which current Internet system assigned similar priorities to all packets during the network are known as the best-effort service. Differentiated Services (DiffServ) model RFC 2475 for the Internet (Blake et al., 1998) has been defined by the Internet Engineering Task Force (IETF) to support the multimedia traffic over the Internet and facilitate true end-to-end QoS on an IP-network as shown in Figure 1. In this model, IP field based type of services (ToS) and traffic is considered by intermediate systems with a comparative priority.

Figure 1.

Differentiated service code point (DSCP)

RFC 2474 defined a differential service (DS) field in the lower 6 bits of the ToS field, and the encoding of the DS field is called differentiated service code point (DSCP). In the DiffServ field architecture, the last two Currently Unused (CU) bits in the DiffServ field were not defined. As defined in RFC3168 (Ramakrishnan, Floyd, & Black, 2001), DSCP and CU are now used as Explicit Congestion Notification (ECN) bits. In a DiffServ network, classification of packets is marked by either DSCP value or IP priority value through the router at the boundary of the network.

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