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