Improved image transmission over wireless channels

An improved technique for image transmission over wireless channel with flat Rayleigh fading is considered in this paper. The proposed scheme minimizes the mean-square error in image transmission rather than the bit error rate. The minimization is done by optimizing the power allocated to each bit according to its importance to the image quality along with the use of channel coding. An algorithm that works iteratively to achieve this goal is presented and analyzed in this paper. It is shown that the proposed technique provides significant gain compared to conventional schemes that send the same power for all bits. It also provides better performance compared to the case were power allocation alone or coding alone is used, with a gain of 2 to 3 dB. It also provides a good performance in terms of reducing the peak-to-average power ratio compared to the case of power allocation alone.