A Joint Power Allocation and Adaptive Channel Coding Scheme for Image Transmission over Wireless Channels

In this paper, a joint adaptive power allocation and channel coding optimization scheme is proposed. This scheme exploitsthe difference in importance among bits used to represent an image or video signal. An offline iterative algorithm is developedto find the optimum combination of coding and power to be used for the transmission of individual bits. Optimality here is inthe sense of minimizing the mean square error (MSE) which results in a better quality of the reconstructed image. Simulationresults show that bits of significant importance should always be coded and allocated most of the transmitted power while bits ofless significance may be sent without coding and with less allocated power. This is done while maintaining the average per-bitenergy at the same level. Simulation results also show that the proposed combined approach achieves a gain of about 3 dB whencompared to the case of coding alone. In addition, the proposed scheme outperforms the case of power allocation alone whilereducing the peak-to-average power ratio.