Network functions for the application of multi-rate speech coding in digital cellular systems

Multi-rate speech coding is a considerable subject in digital cellular systems using highly efficient speech coding methods. The paper describes network functions for the application of the multi-rate speech coding network. As an example of multi-rate coding, functions of a half rate speech coding method in personal digital cellular (PDC) systems are mainly discussed. One of the functions is a codec bypassed connection control to reduce the degradation of voice quality in communication from a mobile station to a mobile station. We propose speech coding negotiation schemes between the originating and terminating MS for the codec bypassed connection control. We also propose a non-voice service connection control scheme which is necessary to provide non-voice services with the same quality as a full rate coding