Abstract: Various embodiments are described to address the need for a method and apparatus of voice transcoding in a VoIP environment that effectively interconnects multiple voice encoding formats. In general, a packet-based tandem transcoder (201) receives (706) packets that include vocoder data frames in which source voice samples have been encoded according to a first vocoding format. The transcoder then decodes (708) the vocoder data frames to produce a sequence of linear speech samples. Using a non-circuit switched communication path, an encoder obtains (710) linear speech samples from the sequence of linear speech samples and encodes (712) groups of speech samples from the sequence of linear speech samples to produce vocoder data frames according to a second vocoding format.

Abstract: A cellular communications system may include one or more cellular base stations and a plurality of mobile cellular communications devices for communicating therewith. More particularly, the cellular base station and the mobile cellular communications devices may each include an encoder for generating an information signal. Furthermore, a modulator may generate a modulated waveform based upon the information signal, a carrier signal having a frequency and phase associated therewith, and at least one carrier phase reference symbol. The modulator may also include an offset circuit so that the modulated waveform includes a carrier frequency indicator. A transmitter may also be included for transmitting the modulated waveform to the desired cellular base station or mobile cellular communications device.

Abstract: A transcoder (40) includes a method for assigning transcoder channel elements (43, 44). The transcoding assignment method selects a DSP (60-75) selects a DSP (channel element) of the required type which has available channel elements (98). Further, the transcoding assignment method may dynamically reassign (118) DSPs from one channel element type to another.

Abstract: Transcoding needs and selection are performed by a central call control function (17, 35). Each transcoder (18, 23, 34, 36) registers with the appropriate call control (17, 35). The call control then determines whether a vocoder is required at all. If vocoding is required, call control (17, 35) selects the appropriate transcoder (18, 34) and inserts the appropriate transcoder into the bearer traffic stream (16).