06138022 is referenced by 28 patents and cites 11 patents.

The present invention provides a novel system and a method for improving the voice quality of wireless-to-wireless calls or wireless-to-fixed terminal calls, while permitting a more efficient utilization of network resources. In a first aspect, the invention provides a communication system including a plurality of base stations connected to one another through a digital network (such as TDM, frame relay or ATM). Also, a plurality of vocoder channels, separate from the individual base stations, provide a data flow path from the base stations to wireline terminals first through the digital network via a Mobile Switching Center and finally through a landline network. In a wireless-to-wireless call, the compressed audio signal travels from one base station to another without undergoing any de-compression/compression. This avoids undesirable vocoder tandeming known to degrade voice quality. If the call is identified as being of a wireless-to-wireline terminal nature, the data is directed to a vocoder channel for decompression into PCM samples. The samples are then transmitted to the fixed terminal through the landline network. The main advantage of this network architecture is that fewer vocoders are required by comparison to prior art systems, therefore fewer costs are incurred. In addition, voice quality is improved.

Title
Cellular communication network with vocoder sharing feature
Application Number
8/898867
Publication Number
6138022
Application Date
July 23, 1997
Publication Date
October 24, 2000
Inventor
Rafi Rabipour
Cote St. Luc
CA
Bill W A Gage
Stittsville
CA
Leo Strawczynski
Ottawa
CA
Assignee
Nortel Networks Corporation
CA
IPC
G01R 31/08
H04M 1/00
H04B 1/38
H04Q 7/20
View Original Source