This TR presents the outcome of the Study Phase initiated at SMG#20 on the concept of the Adaptive Multi-Rate (AMR) codec. The AMR concept represents a new approach to achieving consistent high quality speech combined with efficient spectrum usage. It was recognized at SMG#20 that this would require novel techniques whose feasibility should first be assessed before proceeding with a full development of the AMR system and its control.
Clauses 1 to 4 provide an overview and background to the AMR concept. Clause 5 provides a basic description of the AMR system functionality including working assumptions that have been agreed during the Study Phase. Feasibility aspects are considered in clause 6. The requirement specification, which will form the basis for the development phase, is contained in clause 7. Clause 8 gives an indication of the MS and network upgrades needed to support AMR. Clause 9 outlines how the AMR codec will be developed, tested and selected including the proposed time-plan. Clauses 10 and 11 conclude with a summary of the risks and recommendations.