Improving scalable video transmission over IEEE 802.11e networks

Providing a certain quality of service (QoS) for multimedia transmissions over a noisy wireless channel has always been a challenge. The IEEE 802.11 standardization dedicates a working group, group e, to investigate and propose a solution for enabling IEEE 802.11 networks to provide multimedia transmissions with certain QoS supports. As drafted in the latest draft release, the IEEE 802.11e working group proposes the use of contention based mechanism to achieve the transmissions of prioritized traffic, which in turn provides a framework to support multimedia transmissions over IEEE 802.11 networks. However, such a contention based priority scheme does not deliver a strong QoS capability. In this paper, we first study the characteristics of the IEEE 802.11e network. For all the four defined priorities of IEEE 802.11e, we first investigate their capacity characteristics. We then design a resource allocation technique to better utilize the bandwidth and improve the performance of video transmissions. Our design uses a QoS mapping scheme according to the IEEE 802.11e protocol characteristics to deliver scalable video. In addition, we design an appropriate cross-layer video adaptation mechanism for the scalable video that further improves the video quality combining with our proposed resource allocation technique. We have evaluated our proposed technique via simulations (NS2). We use PSNR as our video quality measures. Our results show improvement in video quality and resource usage when our proposed technique is implemented