Patent ID: 7203638

Claim:
An interworking apparatus, comprising a unit operable with a source-controlled Variable bit-rate Multi-mode WideBand (VMR-WB) codec providing a mode of operation that is interoperable with an Adaptive Multi-Rate wideband (AMR-WB) codec, where in a VMR-WB encoding/AMR-WB decoding case, speech frames are encoded in an AMR-WB interoperable mode of a VMR-WB encoder using one of bit rates corresponding to Interoperable-Full Rate (I-FR) for active speech frames, Interoperable-Half Rate (I-FIR) at least for dim-and-burst signaling, Quarter Rate-Comfort Noise Generator (CNG-QR) to encode at least relevant background noise frames and Eighth Rate-Comfort Noise Generator (CNG-ER) frames for background noise frames not encoded as CNG-QR frames, said interworking apparatus operable such that, invalid frames are transmitted to an AMR-WB decoder as erased frames; I-FR frames are transmitted to the AMR-WB decoder as 12.65, 8.85 or 6.60 kbps AMR-WB frames depending on the I-FR type; CNG-QR frames are transmitted to the AMR-WB decoder as Silence Descriptor Update (SID_UPDATE) frames; CNG-ER frames are transmitted to the AMR-WB decoder as NO_DATA frames; and I-HR frames are translated to 12.65, 8.85, or 6.60 kbps frames, depending on the frame type, by generating missing algebraic codebook indices, where bits indicating the I-HR type are discarded.