A PERFORMANCE STUDY OF ADAPTIVE FEC MECHANISM FOR VIDEO TRANSMISSION OVER 802.11 WLANS

Abstract

Forward Error Correction has been implemented with Automatic Repeat reQuest to overcome packet losses and avoid network congestion in various wireless network conditions. The number of FEC packets is needed to be generated adaptively due to various network states and burst error condition. There are a number of proposed Adaptive FEC mechanisms that can generate FEC packets adaptively for wireless network. However, this current Adaptive FEC, namely Mend FEC mechanism has major drawbacks including injecting excessive number of FEC packets into the network and consequently reducing recovery performance. This paper proposed an enhancement on Mend FEC mechanism, which is called Enhanced Adaptive FEC (EnAFEC) mechanism. The enhancement is aimed to improve recovery performance of the Mend FEC mechanism by generating FEC packets dynamically based on varying wireless network conditions. The proposed enhancement was implemented in simulation environment using the NS2 network simulation. The results show that EnAFEC mechanism outperformed the other Adaptive FEC mechanism in terms of recovery efficiency. This paper also highlights that even minimal amount of FEC packets can recover high packet losses and achieve good video quality at the receiver.

Keywords

• Forward error correction
• Automatic repeat reQuest
• Smoothing factor
• Block length adaptation
• Burst error
• Wireless network