Robust mobile image transmission using hierarchical QAM

Abstract

Abstract This paper proposes a robust hierarchical image transmission system based on the hierarchical quadrature amplitude modulation (QAM) scheme, which gives high-quality image transmission in a band-limited Rayleigh fading channel. Authors examine the selection of Bose–Chaundhuri–Hocquenghem (BCH) error correction codes for two-layer system, and clarified that it is effective to apply forward error correction (FEC) codec to only base significant layer to get higher system performance. By using BCH(63,45,3) code for significant layer, there is about 10 dB improvement of the robustness against channel CNR degradation, with slightly image quality degradation in higher channel CNR region. Authors also analyzed the optimum hierarchical parameter in the Rayleigh fading channel which maximizes the received image quality. Using optimized hierarchical modulation, there is another 2 dB improvement of the robustness against channel CNR degradation.