Re-formatting variable-rate vocoder frames for inter-system transmissions

1. An apparatus for supporting variable-rate vocoder frames within a non-compatible system, comprising:

a demodulation subsystem for demodulating a received multi-rate vocoder frame;

a system discriminator for determining whether the demodulated multi-rate vocoder frame carries a variable-rate vocoder frame as cargo;

a combiner for re-ordering the multi-rate vocoder frame cargo into a variable-rate vocoder frame;

a decoder configured to decode the variable-rate vocoder frame; and

a rate detector to determine a frame type of the decoded variable-rate vocoder frame.

2. The apparatus of claim 1 , wherein the non-compatible system is a Global System for Mobile (GSM) system.

3. The apparatus of claim 1 , wherein the non-compatible system is a wideband code division multiple access (WCDMA) system.

4. A method for supporting variable-rate vocoder frames within a non-compatible system, comprising:

receiving a multi-rate vocoder frame;

determining whether the multi-rate vocoder frame carries a variable-rate vocoder frame cargo;

if the multi-rate vocoder frame carries a variable-rate vocoder frame cargo, then:

identifying a frame type of the variable-rate vocoder frame cargo;

re-ordering the variable-rate vocoder frame cargo into a variable-rate vocoder frame;

decoding the variable-rate vocoder frame; and

determining a frame type of the decoded variable-rate vocoder frame.

5. An apparatus for supporting transmission of variable-rate vocoder frames within a non-compatible system, each variable-rate vocoder frame having a frame type selected from a set of frame types according to speech activity, the frame types comprising full rate, half rate, quarter rate and eighth rate, the apparatus comprising:

an infrastructure element configured to identify a frame type of a received variable-rate vocoder frame, to re-order bits of the received variable-rate vocoder frame according to the identified frame type, and to construct a multi-rate vocoder frame using the re-ordered bits, wherein the infrastructure element is further configured to select a non-working bit pattern from a set of non-working bit patterns and place the selected non-working bit pattern at predetermined bit positions to distinguish the identified frame type from other frame types.

6. An apparatus for supporting transmission of variable-rate vocoder frames within a non-compatible system, each variable-rate vocoder frame having a frame type selected from a set of frame types according to speech activity, the frame types comprising full rate, half rate, quarter rate and eighth rate, the apparatus comprising:

an infrastructure element configured to identify a frame type of a received variable-rate vocoder frame, to re-order bits of the received variable-rate vocoder frame according to the identified frame type, and to construct a multi-rate vocoder frame using the re-ordered bits, wherein the infrastructure element is configured to embed all variable-rate vocoder frames within a single fixed rate mode of a multi-rate vocoder.

7. The apparatus of claim 6 , wherein the single fixed rate mode is a previously un-assigned mode of the multi-rate vocoder.

8. An apparatus for supporting transmission of variable-rate vocoder frames within a non-compatible system, each variable-rate vocoder frame having a frame type selected from a set of frame types according to speech activity, the frame types comprising full rate, half rate, quarter rate and eighth rate, the apparatus comprising:

an infrastructure element configured to identify a frame type of a received variable-rate vocoder frame, to re-order bits of the received variable-rate vocoder frame according to the identified frame type, and to construct a multi-rate vocoder frame using the re-ordered bits, wherein the infrastructure element is configured to re-order bits of the received variable-rate vocoder frame as class A, class B or class C bits of the multi-rate vocoder frame.

9. An apparatus for supporting transmission of variable-rate vocoder frames within a non-compatible system, each variable-rate vocoder frame having a frame type selected from a set of frame types according to speech activity, the frame types comprising full rate, half rate, quarter rate and eighth rate, the apparatus comprising:

an infrastructure element configured to identify a frame type of a received variable-rate vocoder frame, to re-order bits of the received variable-rate vocoder frame according to the identified frame type, and to construct a multi-rate vocoder frame using the re-ordered bits, wherein the infrastructure element is configured to carry each of the four variable-rate vocoder frame types in a different fixed-rate mode of a multi-rate vocoder.

10. An apparatus for supporting transmission of variable-rate vocoder frames within a non-compatible system, each variable-rate vocoder frame having a frame type selected from a set of frame types according to speech activity, the frame types comprising full rate, half rate, quarter rate and eighth rate, the apparatus comprising:

an infrastructure element configured to identify a frame type of a received variable-rate vocoder frame, to re-order bits of the received variable-rate vocoder frame according to the identified frame type, and to construct a multi-rate vocoder frame using the re-ordered bits, wherein the infrastructure element is configured to embed contents of variable-rate vocoder frames into a plurality of already-reserved modes of a multi-rate vocoder.

11. The apparatus of claim 10 , wherein the infrastructure element is configured to construct a multi-rate vocoder frame with overhead bits indicating presence of the variable-rate vocoder frame.

12. The apparatus of claim 10 , wherein the infrastructure element is configured to construct a multi-rate vocoder frame with overhead bits indicating the frame type of the variable-rate vocoder frame.

13. An apparatus for supporting transmission of variable-rate vocoder frames within a non-compatible system, each variable-rate vocoder frame having a frame type selected from a set of frame types according to speech activity, the frame types comprising full rate, half rate, quarter rate and eighth rate, the apparatus comprising:

an infrastructure element. configured to identify a frame type of a received variable-rate vocoder frame, to re-order bits of the received variable-rate vocoder frame according to the identified frame type, and to construct a multi-rate vocoder frame using the re-ordered bits, wherein the infrastructure element is configured to embed four variable-rate vocoder frame types within three fixed-rate modes of a multi-rate vocoder.

14. An apparatus for supporting variable-rate vocoder frames within a non-compatible system, comprising:

a demodulation subsystem for demodulating a received multi-rate vocoder frame;

a system discriminator for determining whether the demodulated multi-rate vocoder frame carries a variable-rate vocoder frame as cargo;

a combiner for re-ordering the multi-rate vocoder frame cargo into a variable-rate vocoder frame; and

a decoder configured to decode the variable-rate vocoder frame, wherein the system discriminator is configured to determine whether the demodulated multi-rate vocoder frame carries a variable-rate vocoder frame as cargo by at least one of searching for a mode index value, searching for a special non-working bit pattern, and blind rate detection.

15. A computer program product, comprising:

computer-readable medium comprising:

code for causing at least one computer to receive a multi-rate vocoder frame;

code for causing at least one computer to determine if the multi-rate vocoder frame carries a variable-rate vocoder frame cargo, wherein if the multi-rate vocoder is determined to carry a variable-rate vocoder frame cargo, then:

identify a frame type of the variable-rate vocoder frame cargo;

re-order the variable-rate vocoder frame cargo into a variable-rate vocoder frame; and

decode the variable-rate vocoder frame

determine a frame type of the decoded variable-frame vocoder frame.

16. An apparatus for supporting variable-rate vocoder frames within a non-compatible system, comprising:

means for receiving a multi-rate vocoder frame;

means for determining whether the multi-rate vocoder frame carries a variable-rate vocoder frame cargo, wherein if the multi-rate vocoder frame carries a variable-rate vocoder frame cargo, then identifying a frame type of the variable-rate vocoder frame cargo;

means for re-ordering the variable-rate vocoder frame cargo into a variable-rate vocoder frame;

means for decoding the variable-rate vocoder frame; and

means for determining a frame type of the decoded variable-rate vocoder frame.