Technology to provide high quality wireless communications

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 speed data."

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 patterns.

A complete copy of the test results is available by contacting the CDG.

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.