Study of the Behaviour of Video Streaming over IEEE 802.11b WLAN Networks

The performance of video streaming over WLAN networks is not only influenced by the state of the network but also by the encoding configuration parameters of the video stream, such as the video content being streamed, how the video is encoded and how it is transmitted. In this paper, we analyze the unique delay characteristic of video streaming applications in a WLAN environment. We show that the "burstiness" of video is due to the frame-based nature of encoded video. We show how each video frame is transmitted as a burst of packets that is queued at the Access Point causing the delay to exhibit a sawtooth-like characteristic over time that is related to the frame rate and frame structure of the encoded video. To our knowledge, this sawtooth-like characteristic of video streaming over WLAN has not been previously reported on. In this paper, not only do we consider the end-to-end delay, but more importantly we consider the total delay required to transmit the entire video frame. We present experimental results for VBR and CBR video streams and calculate the upper bounds on video encoding parameters for streaming real-time interactive video over a WLAN