Optimal real time DSP implementation of ITU G.729 speech codec

Spectral efficiency is the most important aspect in wireless communication systems and cellular mobile radio. As speech transmissions are the most used form of communications in the personal communication systems, the low bit speech codecs play an important role in determining the system's spectral efficiency. A toll quality low bit rate speech codec that was proposed to meet the personal communication system's requirement is the CS-ACELP speech codec. The speech codec has high robustness to withstand high-bit error rates and performs well in tandeming conditions, hence leading to efficient bandwidth utilization and increased channel capacity. In this paper several optimization techniques are presented for efficient implementation of ITU G.729 standard (CS-ACELP, conjugate structure algebraic code excited linear prediction) of 8 Kbit/s bit rate on a real time digital signal processor (DSP), with the aim of overcoming the limitation of computational burden and also scaling this application for enhanced speed to process more channels. These techniques are in general applicable to any speech codec and DSP processor platform.