The EFR voice codec is a coding algorithm that facilitates the conversion of analogue speech into a digital data stream that can be modulated for transmission over the radio channel. The algorithm is fully compatible with a GSM 13 kbit per second speech channel.
Additionally, the US market has also chosen Nokia’s EFR voice codec as the industry standard for PCS 1900. The move was initiated by the potential PCS 1900 operators to significantly improve the PCS voice quality issues. The evaluation of the candidate vocoders was based on quality, complexity, impact on equipment and time schedule.
Based on technology developed at the University of Sherbrooke, the voice codec provides many benefits to GSM and DCS operators. Testing has shown that the voice quality of the EFR codec is comparable to landline voice quality and provides the highest quality of any mobile communications technology.
The codec is fully compatible with existing GSM/DCS infrastructure so it allows for fast implementation at a low cost. It also extends the range of GSM/DCS quality coverage because the codec is more robust to non-voice signals such as music. Landline quality is also retained in environments with excess background noise.