Real-time Implementation of AMR and AMR-WB using the Fixed-point DSP for WCDMA Systems

Abstract

This paper presents an implementation of the AMR and AMR-WB speech codecs using the fixed-point TeakLite DSP for the WCDMA mobile station. Since the AMR and AMR-WB are based on the ACELP coding algorithm and the ACELP requires huge complexity in the codebook search, we especially focused on the optimization of the codebook search routine in our implementations. The implemented AMR and AMR-WB codecs require only 24 MIPS of computation at 12.2 kbps mode and 52.2 MIPS at 23.85 kbit/s mode, respectively by exploiting the DSP architecture and managing the memory structure efficiently. The implemented AMR and AMR-WB codecs were verified through passing all the test vectors provided by 3GPP with maintaining the bit-exactness, and stable operation on the real-time testing board was also confirmed. In addition, to reduce further complexity we propose a fast search method, which improves conventional depth-first tree search method generally utilized in ACELP coding algorithm.