Technology to provide high quality wireless
IRVINE, CALIF. - Advanced speech coding programming that
will bring high quality voice communications to subscribers
using code-division multiple access (CDMA) personal communications
services (PCS) and cellular systems has been developed and
tested by the CDMA Development Group (CDG).
The algorithm, also known as the CDMA 13 kilobit- per-second
(KBPS) vocoder, is contained on a single chip inside a wireless
handset and mobile switching center or base station and is
being deployed in many CDMA cellular and PCS systems worldwide.
The 13 KBPS vocoder, which was approved unanimously by the
43 CDG member companies, is fully compatible and interoperable
with existing CDMA systems.
The CDG conducted listener testing of the new algorithm at
AT&T Bell Laboratories' Speech Coding Test Center in Holmdel,
New Jersey. In almost 1,000 separate tests, more than 100
listeners compared the sound quality of the new algorithm
with wireline and other wireless technologies. In all cases
the algorithm improved voice quality dramatically.
"There is no doubt that with this new speech coding technology
will bring high quality voice communications to CDMA and PCS
systems," said George Zysman, technology vice president
of AT&T Network Systems' wireless equipment group. "The
13 KBPS vocoder has been a key factor in why a number of PCS
and cellular operators around the world are selecting CDMA."
Evan Richards, vice president, engineering, Ameritech Cellular
Services, said: "Our customers expect cellular and PCS
voice quality to be as good as, if not better than, the phones
in their offices and homes. We selected CDMA because it can
provide that level of performance, while offering new and
innovative wireless services, such as short messaging."
"Through our implementations, we are finding that CDMA
provides carriers with tremendous capacity advantages over
other digital technologies," said Graham Haddock, vice
president and general manager, Texas Products Division, Motorola
Cellular Infrastructure Group. "Carriers can use this
extra capacity to provide their customers with very high quality
voice communications and unique services, such as very high
The CDG voice quality team evaluated and refined the 13 KBPS
vocoder algorithm, which represents the combined efforts of
some of the world's leading voice quality experts. The Bell
Laboratories lab testing was the last in a series of tests
that the CDG conducted over the past year. The test evaluated
the algorithm under a number of conditions, including background
noise, mobile-to-mobile calling, and male and female speech
A complete copy of the test results is available by contacting
The CDMA Development Group is recognized as the governing
CDMA MoU and is responsible for fostering the deployment of
CDMA cellular and PCS systems throughout the world. The voluntary
group includes many of the world's largest cellular operators
and equipment manufacturers. Currently, there are nearly a
dozen technical teams and over 400 individuals working to
define specifications and plans for CDMA features and services.