Scheduled and Contention Access Transmission of Partitioned H.264 Video Over WLANs
Supporting Multimedia applications, such as video, over 802.11 wireless local area networks (WLAN) is a challenging task due to the inefficiency of the 802.11 MAC layer and the constant fluctuations in channel error rates. Therefore, specific measures must be taken in both application and delivery layers in order to achieve efficient and satisfactory quality for multimedia applications. Advanced video compression technologies, such as H.264, provide new data partitioning error resiliency feature that allows delivery of the video data in different streams with different levels of importance. There are several possible schemes for mapping these streams to the services of the IEEE 802.1 le MAC. In this article we examine the existing schemes and propose new mechanisms that improve the performance of the video communications system. We propose to use scheduled access schemes in MAC, along with aggregation of packets in the application layer to achieve the best results. We evaluate our proposed mechanisms using simulation experiments.