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A Brief Summary of Codec Tests for IS-95A, IS-95B and IS-2000

A Brief Summary of Codec Tests for IS-95A, IS-95B and IS-2000. Steven D. Gray. Slide 1. Motivation. Discussions in March meeting attempted to define performance requirements for voice lacency and error Two primary methods exist for encoding speech Waveform encoding (i.e., ADPCM)

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A Brief Summary of Codec Tests for IS-95A, IS-95B and IS-2000

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  1. A Brief Summary of Codec Tests for IS-95A, IS-95B and IS-2000 Steven D. Gray Slide 1 Steven Gray, NOKIA

  2. Motivation • Discussions in March meeting attempted to define performance requirements for voice lacency and error • Two primary methods exist for encoding speech • Waveform encoding (i.e., ADPCM) • Parametric endoding (i.e., CELP) • Data summaring performance of contest is presented • 8 new codecs • Enhanced Variable Rate Codec (EVRC) • Codecs Mean Opinion Score (MOS) are rated for • Frame loss rate • Average rate of codec Slide 2 Steven Gray, NOKIA

  3. Summary • MOS score can range from 1 - 5 • Extensive tests were conducted by COMSAT Labs1 in September 1999 on new codecs for IS-95 based CDMA • Assumptions • Variable rate operation • 8, 4, 2 and 1 kbps source encoder rate • 20 ms framing of data • Error detection of bad frames (i.e., CRC) • Average results for all codecs MOS 1. Frank Corcoran, "SMV-Selection Test - Preliminary Test Results," 3GPP2-C11-20000425-023, Seattle Washington, April 25 - 28, 2000. Steven Gray, NOKIA Slide 3

  4. Conclusion • Codecs designed for wireless channels target a frame loss rate with error detection for bad frames at 1 % • 20 ms frames • 8 Kbps for full rate • Codecs not designed for wireless channels could suffer severe error propagation at 1% frame loss Steven Gray, NOKIA Slide 4

  5. Final Note • End-to-end latency in IS-95A networks • Mobile-to-fixed terminal is approximately 120 ms • Mobile-to-mobile terminal is approximately 180 ms Steven Gray, NOKIA 5

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