An Unequal Protection Method for Multiuser OFDM to Minimize Video Distortion

Abstract

This paper proposes multiuser orthogonal frequency division multiplexing system for compressed video packets. Normally, video coding technologies compress video contents by removing similarities inherent in the video contents, so that it causes dependencies among the packets. It eventually results in inequality in terms of influence on video distortion, so that unequal protection is required to achieve better performance. As one way to impose priority on the compressed video packets, this paper proposes to set target bit error rate according to the influence of each packet. We modified an existing multiuser orthogonal frequency division multiplexing system to consider the target bit error rate imposed on each packet when allocating sub channels. For the same resulting video distortion, proposed system with the adaptive target bit error rate roughly doubled channel capacity from a system with fixed target bit error rate, where a specific circumstances of transmit power and bandwidth in this paper is assumed. Futhermore, fairness in terms of video distortion can be obtained by equalizing the target video distortion values.