Transmission of multimedia, especially transmission of image/video information, requires high reliability and high digital transmission speed. But, in case of mobile communication systems, since transmission reliability is degraded by multipath fading also the frequency bandwidth is severely limited, it is difficult to realize the multimedia transmission without applying techniques to overcome these limitations. For achieving a high quality and high speed in digital image transmission in a band-limited fading channel, Hierarchical modulation is a better method. This method is also constellation is used to give different degrees of error protection for the most important information of the image content. A higher order i. e. 256-HQAM where non-uniform signal constellation with hierarchical oriented OFDM modulator has been proposed. Proposed method is used to provide lesser BER and Bandwidth efficiency in the compressed image data at lower channel Signal to Noise Ratio (SNR). An information theoretical approach is applied to analyze the performance of proposed technique. Using the approach, it is quantitatively evaluated how much the proposed technique outperforms. BER and PSNR of reconstructed image of proposed methodology, which include uniform and non-uniform constellations, over AWGN environments, have been calculated to analyze the performance. The performance of proposed and existing technique has been evaluated by doing simulation using MATLAB 7. 6 (R2008a).

LP HP Modulation HQAM Constellation.