Adaptive modulation approach for robust MPEG-4 AAC encoded audio transmission

In this paper, we present a robust transmission scheme for MPEG-4 AAC encoded audio data over fading wireless channels using Unequal Error Protection based on adaptive modulation and forward error correcting (FEC) codes. The encoded audio data is divided into three error sensitivity categories and a suitable combination of FEC and modulation order is determined for each category. The results are compared with non-adaptive (single order) modulation with FEC for the same channel conditions. Perceptual Evaluation of Audio Quality (PEAQ)-Objective Difference Grade (ODG) score has been chosen to measure decoded audio quality. Simulation results are presented as PEAQ-ODG score vs. channel signal to noise ratio at a fixed channel bandwidth. The proposed scheme achieves significant performance gain over the non-adaptive error protection scheme.