Scalable video transmission over orthogonal frequency division multiplexing wireless channels

We optimize a wireless system for video transmission over orthogonal frequency division multiplexing (OFDM) systems. A frequency-selective Rayleigh fading channel is assumed. Block transmissions using a cyclic prefix are used to eliminate interblock interference (IBI). Quadrature amplitude modulation (QAM) is used as modulation scheme. The MPEG-4 video coder is used to provide a two-layer SNR scalable video bit stream. Rate compatible punctured convolutional codes (RCPC codes) are used for error protection. We apply unequal error protection (UEP) to the layers of the scalable bitstream. We solve the problem of optimal bit allocation between source and channel coding and across scalable layers such that the overall distortion is minimized. The algorithm utilizes universal rate distortion characteristics which are obtained experimentally and show the sensitivity of the source encoder and decoder to channel errors.