Cross-layer unequal error protection using 64-HQAM and RCPT codes for robust image communication

Abstract

In unequal error protection (UEP) schemes, the bits are protected according to their significance in terms of distortion reduction capability during the reconstruction process. The conventional UEP schemes are primarily designed either using forward error correction at application layer of network architecture, or hierarchical modulation at the physical layer. In this paper, an optimized cross-layer UEP scheme for set partitioning in hierarchical trees coded images is investigated. The proposed scheme uses rate compatible punctured turbo codes at application layer and two-layered 64-hierarchical QAM (64-HQAM) at physical layer. Simulation results show that proposed cross-layer UEP performs slightly better than application layer’s optimized turbo coding for additive white Gaussian noise channel but performs significantly better in flat Rayleigh fading channel, specifically under poor channel conditions. The proposed scheme is highly bandwidth efficient having the robustness performance close to that of the scheme using hierarchical 4-PAM (H 4-PAM). Complexity analysis of the proposed solution has been carried out.