<title>Two-stage FEC scheme for scalable video transmission over wireless networks</title>

Abstract

In this paper, we propose a two-stage FEC scheme with an enhanced MAC protocol especially for multimedia data transmission over wireless LANs. The proposed scheme enables the joint optimization of protection strategies across the protocol stack, and packets with errors are delivered to the application layer for correction or drop. In stage 1, packet-level FEC is added across packets at the application layer to correct packet losses due to congestion and route disruption. In stage 2, bit-level FEC is processed within both application packets and stage-one FEC packets to recover from bit errors in the MAC/PHY layer. Header CRC/FEC are used to enhance the MAC/PHY layer and to cooperate with the two stage FEC scheme. Thus, we add FEC only at the application layer, but can correct both application layer packet drops and MAC/PHY layer bit errors. We explore both the efficiency of bandwidth utilization and video performance using the scalable video coder MC-EZBC and ns-2 simulations. Simulation results show that the proposed scheme outperforms conventional IEEE 802.11.