Nortel Test Reveals Code Division Multiple Access (CDMA) Offers Wireline Telephone Voice Quality
August 28, 1996OTTAWA -- Nortel today announced that vocoder tests recently conducted in Ottawa at the company's renowned Subjective Assessment Laboratory show that state-of-the art Code Division Multiple Access (CDMA) speech coders offer competitive voice quality equivalent to wireline telephones.
"Nortel's findings confirm that CDMA-based users will be able to enjoy the same level of voice performance from their PCS and cellular handsets as they expect from their home- or office-based wireline telephone handsets today," said Matt Desch, group vice president and general manager, Wireless Networks, Nortel.
The tests, carried out on behalf of the CDMA Development Group (CDG), were the first to include a formal subjective comparison of the performance of the leading speech codecs - the 8kbps Enhanced Variable Rate Codec (EVRC) and the QUALCOMM 13 kbps Pure Voice Codec. Results also showed that the latest Time Division Multiple Access (TDMA) and Global System for Mobile Communications (GSM) coders are capable of providing wireline voice quality.
One hundred and twenty listeners took part in the tests. They rated speech with input impairments such as background noise, as well as channel impairments to estimate the voice quality over CDMA with the different coders.