A cross layer design to improve video transmission over 802.11e WLANs using error and rate joint control

Abstract

The transmission of WLAN could easily suffer from multi-path or noise interference, which in turn leads to packet loss and the subsequent need of retransmission; moreover, these phenomena could easily lead to the decrease in video transmission quality of some delay-sensitive multimedia applications. Therefore, how to improve the video transmission in WLAN thus becomes a very important issue. In this article, a cross-layer design is proposed to improve video transmission over 802.11e WLANs using error and rate joint control. The network condition estimator (NCE) is designed to distinguish network errors caused by congestion or interference at MAC layer. Based on the information provided from application layer and NCE, the packet-selective rate controller (PSRC) and adaptive TXOP error controller (ATEC) are proposed to eliminate the effect caused by network errors and improve video quality. Simulation results reveal that our crosslayer design is capable of reacting to the varying channel condition with less and smoother quality degradation than several distinct cross-layer schemes.