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

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.

Real-Time Bus Video Monitoring System Based on 3G Network

According to some bottleneck problems of the communication network bandwidth in wireless video transmission, a design scheme of real-time traffic video monitoring system based on 3G network is put forward in this paper. The design of hardware and the software realization of the system process are mainly introduced. TMS320DM8168 is selected to build the hardware platform in this system. H.264 video encoder is integrated internally. The real-time transmission of video data is sent to the remote monitoring center through the 3G network to improve the video transmission quality. The system meets the requirements of video transmission applied in automobiles.

Network Video Transmission Quality Assurance Algorithm Based on Congestion Control

Time delay and packet loss rate during the network video transmission are the two important factors in network video transmission quality. The purpose of congestion control is to reduce the bad impact of network video transmission quality caused by time delay and packet loss rate. This paper proposed a network video transmission quality assurance algorithm based on unbalanced multiple descriptions coding scheme. The new algorithm predicts the congestion state of network by means of Markov model based on available bandwidth detection, changes video transmission path on the basis of the prediction. Experiments show that compared with RED (Random Early Detection) algorithm, the algorithm is much more effective to estimate network congestionreduce video packet loss rate and time delay, thus the network video transmission quality can be ensured more effectively.

A Novel Video Stream Transmission Control Algorithm

Video stream codec and transmission control algorithm is very important to improve quality of service of video on Internet. A priority video transmission algorithm based on queue-length(VTA-QL) is proposed. Different kind of video frame is marked with different priority and is scheduled according to its priority. Simulation results show that the proposed algorithm VTA-QL can improve the video transmission quality greatly, and that link bandwidth, delay and queue length have much effect on video transmission quality.