Close two constituent trellis of a turbo encoder within the interleave block

• US 7,085,985 B2
• Filed: 10/04/2002
• Issued: 08/01/2006
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Shen, Ba-Zhong, Cameron, Kelly Brian
• Primary Examiner(s): Lamarre, Guy J.
• Application Number:
  US10/264,767
• Publication Number:
  US 20030226088A1
• Time in Patent Office: 1,397 Days
• Field of Search: 714/755, 714/786, 714/792, 714/795, 714/756, 714/701, 375/265, 375/341, 375/262
• US Class Current: 714/755
• CPC Class Codes: H03M 13/256 with trellis coding, e.g. with convolutional codes and TCM
• CPC Class Codes: H03M 13/258 with turbo codes, e.g. Turbo Trellis Coded Modulation [TTCM]
• CPC Class Codes: H03M 13/27 using interleaving techniques
• CPC Class Codes: H03M 13/2767 Interleaver wherein the permutation pattern or a portion thereof is stored
• CPC Class Codes: H03M 13/2771 Internal interleaver for turbo codes H03M13/2714 and H03M13/2725 take precedence
• CPC Class Codes: H03M 13/2785 Interleaver using in-place interleaving, i.e. writing to and reading from the memory is performed at the same memory location
• CPC Class Codes: H03M 13/2993 Implementing the return to a predetermined state, i.e. trellis termination
• CPC Class Codes: H03M 13/4123 implementing the return to a predetermined state
• CPC Class Codes: H03M 13/4161 implementing path management
• CPC Class Codes: H04L 1/005 Iterative decoding, including iteration between signal detection and decoding operation
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

Close two constituent trellis of a turbo encoder within the interleave block. The state of a multi-state encoder is forced to a known/predetermined state at the end and beginning of each data frame. Packet based and/or frame based data transmissions benefit greatly when the encoder state of a multi-state encoder is known at the beginning and end of each frame. Appropriately chosen symbols, selected to force the encoder to a known state at the end of a data frame, may be padded to the end of a data frame that is to be encoded; this will force the encoder to “close” at the end of the data frame. These closure symbols may also be padded to the end of the data frame before the data frame in interleaved. Moreover, within encoder embodiments that include multiple constituent encoders, both constituent encoders will be forced to the known/predetermined state.

Claims

1. A method for determining a plurality of closure symbols that will force an encoder to a predetermined state, the method comprising:

assessing a plurality of impulse response states of the encoder;

for each impulse response state of the plurality of impulse response states of the encoder, finding a minimum plurality of input symbols that, when applied to the encoder, will force the encoder to the predetermined state;

for a data frame comprising a plurality of input symbols that will place the encoder into a particular impulse response state, determining a minimum plurality of encoder state transitions required to force the encoder to the predetermined state;

selecting a plurality of closure symbols, from the minimum plurality of input symbols that, when padded to an end of the data frame, will force the encoder to undergo the minimum plurality of encoder state transitions when transitioning from one impulse response state of the plurality of impulse response states to the predetermined state;

padding the plurality of closure symbols to the end of the data frame; and

encoding the data frame; and

wherein the encoding of the data frame forces the encoder to the predetermined state at the end of the data frame.

2. The method of claim 1, wherein the data frame comprises the plurality of closure symbols padded to the end of the data frame and a remaining plurality of input symbols;

and

further comprising interleaving the data frame, that comprises the plurality of closure symbols and the remaining plurality of input symbols, before encoding the data frame.

3. The method of claim 1, wherein the encoder comprises a plurality of registers;

and

the plurality of closure symbols comprises a number of closure symbols that is less than a number of registers of the plurality of registers.

4. The method of claim 3, wherein the encoder comprises three registers;

and

the plurality of closure symbols comprises two closure symbols.

5. The method of claim 1, wherein the encoder comprises at least one of a convolutional encoder, a turbo encoder comprising a single interleaver, a turbo encoder comprising dual interleavers, and a Turbo Trellis Coded Modulation (TTCM) encoder.

6. The method of claim 5, wherein at least one of the turbo encoder comprising a single interleaver, the turbo encoder comprising dual interleavers, and the TTCM encoder comprises two constituent encoders;

and

wherein the encoding of the data frame forces both of the two constituent encoders to the predetermined state.

7. The method of claim 1, further comprising encoding the plurality of input symbols according to a rate control sequence.

8. The method of claim 7, wherein the rate control sequence comprises a plurality of modulations;

and

each modulation of the plurality of modulations comprises a constellation and a mapping.

9. The method of claim 1, wherein the encoder is contained within at least one of a satellite transmitter, a High Definition Television (HDTV) transmitter, a mobile transmitter, a base station transmitter, a transmitter, a mobile unit, a transceiver, and a Dense Wavelength Division Multiplexing (DWDM) line card.

10. The method of claim 1, wherein the encoder is implemented within a communication transmitter;

and

the communication transmitter is contained within at least one of a satellite communication system, a High Definition Television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point communication system, a uni-directional communication system, a bi-directional communication system, a one to many communication system, and a fiber-optic communication system.

11. A method for determining a plurality of closure symbols that will force an encoder to a predetermined state, the method comprising:

assessing a plurality of impulse response states of the encoder;

for each impulse response state of the plurality of impulse response states of the encoder, finding a minimum plurality of input symbols that, when applied to the encoder, will force the encoder to the predetermined state;

for a data frame comprising a plurality of input symbols that will place the encoder into a particular impulse response state, determining a minimum plurality of encoder state transitions required to force the encoder to the predetermined state;

selecting a plurality of closure symbols, from the minimum plurality of input symbols that, when padded to an end of the data frame, will force the encoder to undergo the minimum plurality of encoder state transitions when transitioning from one impulse response state of the plurality of impulse response states to the predetermined state;

padding the plurality of closure symbols to the end of the data frame, the data frame comprises the plurality of closure symbols padded to the end of the data frame and a remaining plurality of input symbols;

interleaving the data frame that comprises the plurality of closure symbols and the remaining plurality of symbols; and

encoding the interleaved data frame; and

wherein the encoding of the data frame forces the encoder to the predetermined state at the end of the data frame.

12. The method of claim 11, wherein the encoder comprises a plurality of registers;

and

the plurality of closure symbols comprises a number of closure symbols that is less than a number of registers of the plurality of registers.

13. The method of claim 12, wherein the encoder comprises three registers;

and

the plurality of closure symbols comprises two closure symbols.

14. The method of claim 11, wherein the encoder comprises at least one of a convolutional encoder, a turbo encoder comprising a single interleaver, a turbo encoder comprising dual interleavers, and a Turbo Trellis Coded Modulation (TTCM) encoder.

15. The method of claim 14, wherein at least one of the turbo encoder comprising a single interleaver, the turbo encoder comprising dual interleavers, and the TTCM encoder comprises two constituent encoders;

and

wherein the encoding of the interleaved data frame forces both of the two constituent encoders to the predetermined state.

16. The method of claim 11, further comprising encoding the plurality of input symbols according to a rate control sequence.

17. The method of claim 16, wherein the rate control sequence comprises a plurality of modulations;

and

each modulation of the plurality of modulations comprises a constellation and a mapping.

18. The method of claim 11, wherein the encoder is contained within at least one of a satellite transmitter, a High Definition Television (HDTV) transmitter, a mobile transmitter, a base station transmitter, a transmitter, a mobile unit, a transceiver, and a Dense Wavelength Division Multiplexing (DWDM) line card.

19. The method of claim 11, wherein the encoder is implemented within a communication transmitter;

and

the communication transmitter is contained within at least one of a satellite communication system, a High Definition Television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point communication system, a uni-directional communication system, a bi-directional communication system, a one to many communication system, and a fiber-optic communication system.

20. A closure operable encoder, the encoder comprising:

a constituent encoder that encodes a plurality of input symbols; and

a closure generator that assesses a plurality of impulse response states of the constituent encoder; and

wherein for each impulse response state of the plurality of impulse response states of the constituent encoder, the closure generator finds a minimum plurality of input symbols that, when applied to the constituent encoder, will force the constituent encoder to the predetermined state;

for a data frame comprising a plurality of input symbols that will place the constituent encoder into a particular impulse response state, the closure generator determines a minimum plurality of encoder state transitions required to force the constituent encoder to the predetermined state;

the closure generator selects a plurality of closure symbols, from the minimum plurality of input symbols that, when padded to an end of the data frame, will force the constituent encoder to undergo the minimum plurality of encoder state transitions when transitioning from one impulse response state of the plurality of impulse response states to the predetermined state;

the closure generator pads the plurality of closure symbols to the end of the data frame; and

the constituent encoder is forced to the predetermined state at the end of the data frame when encoding the data frame.

21. The encoder of claim 20, further comprising an interleaver, communicatively coupled to the constituent encoder, that is operable to interleave the data frame that comprises the plurality of input symbols and the closure symbols;

and

wherein the constituent encoder encodes the interleaved data frame; and

the constituent encoder is forced to the predetermined state at the end of the data frame when encoding the interleaved data frame.

22. The encoder of claim 20, wherein the encoder comprises a plurality of registers;

and

the plurality of closure symbols comprises a number of closure symbols that is less than a number of registers of the plurality of registers.

23. The encoder of claim 22, the encoder comprises three registers;

and

the minimum plurality of input symbols comprises two input symbols.

24. The encoder of claim 20, wherein the encoder comprises at least one of a convolutional encoder, a turbo encoder comprising a single interleaver, a turbo encoder comprising dual interleavers, and a Turbo Trellis Coded Modulation (TTCM) encoder.

25. The encoder of claim 24, wherein at least one of the turbo encoder comprising a single interleaver, the turbo encoder comprising dual interleavers, and the TTCM encoder comprises two constituent encoders;

and

wherein the encoding of the interleaved data frame forces both of the two constituent encoders to the predetermined state.

26. The encoder of claim 20, further comprising a rate control sequencer that directs the encoder to encode the plurality of input symbols according to a rate control sequence.

27. The encoder of claim 26, wherein the rate control sequence comprises a plurality of modulations;

and

each modulation of the plurality of modulations comprises a constellation and a mapping.

28. The encoder of claim 20, wherein the encoder is contained within at least one of a satellite transmitter, a High Definition Television (HDTV) transmitter, a mobile transmitter, a base station transmitter, a transmitter, a mobile unit, a transceiver, and a Dense Wavelength Division Multiplexing (DWDM) line card.

29. The encoder of claim 20, wherein the encoder is implemented within a communication transmitter;

and

the communication transmitter is contained within at least one of a satellite communication system, a High Definition Television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point communication system, a uni-directional communication system, a bi-directional communication system, a one to many communication system, and a fiber-optic communication system.

30. A closure operable dual interleaver turbo encoder that encodes a plurality of input symbols, the encoder comprising:

a top interleaver;

a top constituent trellis encoder that is communicatively coupled to the top interleaver;

a bottom interleaver;

a bottom constituent trellis encoder that is communicatively coupled to the bottom interleaver;

a closure generator that is communicatively coupled to the top interleaver and the bottom interleaver;

a multiplexor that alternatively selects encoded bits that are output from the top constituent trellis encoder and the bottom constituent trellis encoder; and

wherein the closure generator assesses a plurality of impulse response states for both the top constituent trellis encoder and the bottom constituent trellis encoder;

for each impulse response state of the plurality of impulse response states of the top constituent trellis encoder and the bottom constituent trellis encoder, the closure generator finds a minimum plurality of input symbols that, when applied to at least one of the top constituent trellis encoder and the bottom constituent trellis encoder, will force at least one of the top constituent trellis encoder and the bottom constituent trellis encoder to the predetermined state;

for a data frame comprising a plurality of input symbols that will place at least one of the top constituent trellis encoder and the bottom constituent trellis encoder into a particular impulse response state, the closure generator determines a minimum plurality of encoder state transitions required to force at least one of the top constituent trellis encoder and the bottom constituent trellis encoder to the predetermined state;

the closure generator selects a plurality of closure symbols, from the minimum plurality of input symbols that, when padded to an end of the data frame, will force at least one of the top constituent trellis encoder and the bottom constituent trellis encoder to undergo the minimum plurality of encoder state transitions when transitioning from one impulse response state of the plurality of impulse response states to the predetermined state;

the closure generator pads the plurality of closure symbols to the end of the data frame;

the top interleaver interleaves the data frame that comprises the plurality of input symbols and the closure symbols;

the bottom interleaver interleaves the data frame that comprises the plurality of input symbols and the closure symbols; and

at least one of the top constituent trellis encoder and the bottom constituent trellis encoder is forced to the predetermined state at the end of the data frame when encoding the data frame.

31. The encoder of claim 30, further comprising a rate control sequencer that directs the top constituent trellis encoder and the bottom constituent trellis encoder to encode the plurality of input symbols according to a rate control sequence.

32. The encoder of claim 31, wherein the rate control sequence comprises a plurality of modulations;

and

each modulation of the plurality of modulations comprises a constellation and a mapping; and

further comprising a puncturing functional block that punctures a predetermined number of the encoded bits that are output from the multiplexor according to the modulation of the rate control sequence.

33. The encoder of claim 30, wherein the encoder is contained within at least one of a satellite transmitter, a High Definition Television (HDTV) transmitter, a mobile transmitter, a base station transmitter, a transmitter, a mobile unit, a transceiver, and a Dense Wavelength Division Multiplexing (DWDM) line card.

34. The encoder of claim 30, wherein the encoder is implemented within a communication transmitter;

and

the communication transmitter is contained within at least one of a satellite communication system, a High Definition Television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point communication system, a uni-directional communication system, a bi-directional communication system, a one to many communication system, and a fiber-optic communication system.