Cross-layer design for video streaming over QoS-enabled WLANs

• Main Author: Guo, Tiantian.
• Other Authors: Cai Jianfei
• Format: Theses and Dissertations
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Computer science and engineering::Computer systems organization::Computer-communication networks
• Online Access: http://hdl.handle.net/10356/52475
• Institution: Nanyang Technological University

The high penetration of WLANs has encouraged multimedia applications in the public and the home environment. Among various multimedia applications, video streaming is one of the most popular applications for WLANs. However, the characteristics of wireless communications such as limited bandwidth, time-varying channel conditions, dynamic network users, the contention-based WLAN channel access, and the heterogeneous properties of video traffic make video streaming over WLANs a challenging task. The objective of this thesis is to analyze and enhance the QoS performance of video streaming over QoS-enabled WLANs based on cross-layer design, including performance analysis of IPTV over WLANs and QoS enhancement of videophone and a mixture of scalable IPTV and VoD traffic over WLANs. In particular, this thesis first investigates the performance of videophone transmission over multi-rate WLANs. It is found that the WLAN can only support seven videophone users due to the access point (AP) bottleneck problem for symmetric video traffic. We then propose to adjust the transmission opportunity (TXOP) to give AP a higher priority for channel access. We also propose to adjust video source rates to maintain the network at stable conditions. The physical (PHY) multi-rate constraints are carefully considered in our design, particularly for the computation of TXOP and video source rates. Simulation results show that our proposed system can improve the number of videophone sessions to 10.