eAMR: Wideband speech over legacy narrowband networks

This paper introduces eAMR (enhanced-AMR), a novel technique for delivering wideband speech over existing narrowband networks. Instead of using a completely new wideband speech coder which would require new infrastructure, as is the case e.g. for AMR-WB or EVS, eAMR is based on the existing AMR (narrowband) codec, which is already widely deployed. eAMR uses an efficient coding model to represent the high frequencies of the speech signal, and combines it with watermarking technology to hide this data within a normal narrowband AMR bitstream. As a result, eAMR is a wideband codec which is fully compatible with the existing AMR network infrastructure, and therefore can be deployed as a handset-only feature.