Standardized in 3GPP2, Enhanced Variable Rate Codec – B (EVRC-B) for wideband spread spectrum (CDMA) networks is an enhancement to EVRC.

EVRC-B communicates at channel rates corresponding to 9600, 4800, 2400 and 1200 bps frame rates. The speech coder source bit rates corresponding to these channel rates are 8550, 4000, 2000 and 800 bps. EVRC-B operates at these different rates depending on the source signal: full rate (8.5 kbps), half rate (4 kbps), quarter rate (2 kbps) and eighth rate (800 bps). The lowest rate is for background noise. The use of quarter-rate frames, which were not used in EVRC, contributes to a lower average bit rate compared to EVRC for the same voice quality.

Qualcomm's 4GV™ codec suite includes EVRC-B for narrowband speech coding.

For licensing IPR, please contact licensing@voiceage.com.