Apparatus and methods for interleaving in a forward link only system

• US 8,612,820 B2
• Filed: 04/08/2010
• Issued: 12/17/2013
• Est. Priority Date: 04/11/2009
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: van Veen, Durk L., Chari, Murali R., Sun, Thomas
• Primary Examiner(s): MCCARTHY, CHRISTOPHER S
• Application Number:
  US12/756,917
• Publication Number:
  US 20100260161A1
• Time in Patent Office: 1,349 Days
• Field of Search: None
• US Class Current: 714/752
• CPC Class Codes: H03M 13/2703 the interleaver involving at least two directions
• CPC Class Codes: H03M 13/271 Row-column interleaver with permutations, e.g. block interleaving with inter-row, inter-column, intra-row or intra-column permutations
• CPC Class Codes: H03M 13/2735 Interleaver using powers of a primitive element, e.g. Galois field [GF] interleaver
• CPC Class Codes: H03M 13/2771 Internal interleaver for turbo codes H03M13/2714 and H03M13/2725 take precedence
• CPC Class Codes: H03M 13/296 Particular turbo code structure
• CPC Class Codes: H03M 13/6561 Parallelized implementations
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

Methods and devices for encoding and interleaving data packets for broadcast and for de-interleaving and decoding data packets in a communication system eliminate detrimental biasing effects by using pseudo-random M-sequence bit encoding as part of the turbo encoding and decoding. The use of pseudo-random M-sequence bit encoding mitigates biasing effects that may otherwise be introduced if conventional r-c interleaving is applied to long turbo encoded data which would degrade reception in the presence of broadcast interference.

Claims

1. A method of transmitting a plurality of codeblocks in a communication system, the method comprising:

turbo encoding a plurality of codeblocks using a plurality of long turbo encoders to generate a plurality of turbo encoded codeblocks;

interleaving each of the plurality of turbo encoded codeblocks using an M-sequence bit interleaving scheme;

transmitting the plurality of turbo encoded and M-sequence bit interleaved codeblocks;

wherein the M-sequence bit interleaving scheme comprises;

pseudo-randomly generating a maximum length M-sequence state in a linear feedback shift register;

utilizing the linear feedback shift register internal state as a memory location address in a buffer;

obtaining a bit of at least one of the plurality of turbo encoded codeblocks stored in an input buffer at the M-sequence state memory address; and

storing the obtained bit in a next available memory location address in an output buffer.

2. The method of claim 1, wherein interleaving the plurality of turbo encoded codeblocks using the M-sequence bit interleaving scheme is performed on an intra-codeblock basis to form a plurality of intra codeblock interleaved bit streams.

3. The method of claim 2, further comprising:

forming an integer number subpackets of bits from each of the plurality of intra codeblock interleaved bit streams; and

interleaving the formed subpackets from each of the plurality of intra codeblock interleaved bit streams in an inter-codeblock fashion using a round-robin interleaving scheme.

4. The method of claim 1, wherein interleaving the turbo encoded codeblock using the M-sequence bit interleaving scheme is performed on an inter-codeblock basis.

5. An apparatus for use in a broadcast communication system, comprising:

means for turbo encoding a plurality of codeblocks using a plurality of long turbo encoders to generate a plurality of turbo encoded codeblocks;

means for interleaving each of the plurality of turbo encoded codeblocks using an M-sequence bit interleaving scheme; and

means for transmitting the plurality of turbo encoded and M-sequence bit interleaved codeblocks;

wherein the means for interleaving each of the plurality of turbo encoded codeblocks using an M-sequence bit interleaving scheme comprises;

means for pseudo-randomly generating a maximum length M-sequence state in a linear feedback shift register;

means for utilizing the linear feedback shift register internal state as a memory location address in a buffer; and

means for storing a next available bit of at least one of the plurality of turbo encoded codeblocks to the memory location address in the buffer.

6. The apparatus of claim 5, wherein means for interleaving the plurality of turbo encoded codeblocks using the M-sequence bit interleaving scheme comprises means for interleaving the plurality of turbo encoded codeblocks using the M-sequence bit interleaving scheme on an intra-codeblock basis to form a plurality of intra-codeblock interleaved bit streams.

7. The apparatus of claim 6, further comprising:

means for forming an integer number subpackets of bits from each of the plurality of intra-codeblock interleaved bit streams; and

means for interleaving the formed subpackets from each of the intra-codeblock interleaved bit streams in an inter-codeblock fashion using a round-robin interleaving scheme.

8. The apparatus of claim 5, wherein means for interleaving the turbo encoded codeblock using the M-sequence bit interleaving scheme comprises means for interleaving the turbo encoded codeblock using the M-sequence bit interleaving scheme on an inter-codeblock basis.

9. An apparatus for use in a broadcast communication system, comprising:

a memory buffer;

a processor coupled to the memory buffer, wherein the processor is configured with software instructions to perform steps comprising;

turbo encoding a plurality of codeblocks using a plurality of long turbo encoders to generate a plurality of turbo encoded codeblocks;

interleaving each of the plurality of turbo encoded codeblocks using an M-sequence bit interleaving scheme;

transmitting the plurality of turbo encoded and M-sequence bit interleaved codeblocks;

pseudo-randomly generating a maximum length M-sequence state in a linear feedback shift register;

utilizing the linear feedback shift register internal state as a memory location address in the memory buffer; and

storing a next available bit of at least one of the plurality of turbo encoded codeblocks to the memory location address in the buffer.

10. The apparatus of claim 9, wherein the processor is further configured with software instructions to perform steps further comprising:

interleaving the plurality of turbo encoded codeblocks using the M-sequence bit interleaving scheme on an intra-codeblock basis to form a plurality of intra-codeblock interleaved bit streams.

11. The apparatus of claim 10, wherein the processor is further configured with software instructions to perform steps further comprising:

forming an integer number subpackets of bits from each of the plurality of intra-codeblock interleaved bit streams; and

interleaving the formed subpackets from each of the intra-codeblock interleaved bit streams in an inter-codeblock fashion using a round-robin interleaving scheme.

12. The apparatus of claim 9, wherein the processor is further configured with software instructions to perform steps further comprising:

interleaving the turbo encoded codeblock using the M-sequence bit interleaving scheme on an inter-codeblock basis.

13. A non-transitory storage medium having stored thereon processor-executable software instructions configured to cause a processor in a broadcast communication system to perform steps comprising:

turbo encoding a plurality of codeblocks using a plurality of long turbo encoders to generate a plurality of turbo encoded codeblocks;

interleaving each of the plurality of turbo encoded codeblocks using an M-sequence bit interleaving scheme;

transmitting the plurality of turbo encoded and M-sequence bit interleaved codeblocks;

pseudo-randomly generating a maximum length M-sequence state in a linear feedback shift register;

utilizing the linear feedback shift register internal state as a memory location address in the memory buffer; and

storing a next available bit of at least one of the plurality of turbo encoded codeblocks to the memory location address in the buffer.

14. The non-transitory storage medium of claim 13, wherein the tangible storage medium has processor-executable software instructions configured to cause a processor in a broadcast communication system to perform further steps comprising:

interleaving the plurality of turbo encoded codeblocks using the M-sequence bit interleaving scheme on an intra-codeblock basis to form a plurality of intra-codeblock interleaved bit streams.

15. The non-transitory storage medium of claim 14, wherein the tangible storage medium has processor-executable software instructions configured to cause a processor in a broadcast communication system to perform further steps comprising:

forming an integer number subpackets of bits from each of the plurality of intra-codeblock interleaved bit streams; and

interleaving the formed subpackets from each of the intra-codeblock interleaved bit streams in an inter-codeblock fashion using a round-robin interleaving scheme.

16. The non-transitory storage medium of claim 13, wherein the tangible storage medium has processor-executable software instructions configured to cause a processor in a broadcast communication system to perform further steps comprising:

interleaving the turbo encoded codeblock using the M-sequence bit interleaving scheme on an inter-codeblock basis.

17. An apparatus for use in a broadcast communication system, comprising:

a plurality of long turbo encoders each configured to encode one of a plurality of codeblocks for transmission in a channel thereby generating a plurality of turbo encoded codeblocks;

at least one M-sequence interleaver configured to interleave each of the plurality of turbo encoded codeblocks;

a transmitter for transmitting the plurality of turbo encoded and m-sequence bit interleaved codeblocks;

an M-sequence pseudo-random sequence generator;

a maximum length linear feedback shift register for generating the M-sequence pseudo-random sequence;

a memory buffer;

a processor configured to interpret each member of the M-sequence pseudo-random sequence as a memory location address in the memory buffer and to store a next available bit of at least one of the plurality of turbo encoded codeblocks to the memory location address in the memory buffer.

18. The apparatus of claim 17, further comprising a plurality of M-sequence interleavers wherein each of the plurality of M-sequence interleavers is configured to interleave one of the plurality of turbo encoded codeblocks in an intra-codeblock basis.

19. The apparatus of claim 18, further comprising:

a plurality of subpacket forming modules, each configured to form an integer number subpackets of bits from the intra-codeblock interleaved bit stream; and

a round robin interleaver configured to interleave the formed subpackets from each of the plurality of subpackets forming modules across multiple frames of a group of frames by respectively placing subpackets of each of the plurality of long turbo encoded packets into different frames of the group of frames.

20. The apparatus of claim 17, wherein the at least one M-sequence interleaver is configured to interleave each of the turbo encoded codeblocks from each of the plurality of long turbo encoders across multiple frames of a group of frames by respectively placing subpackets of each of the plurality of long turbo encoded packets into different frames of the group of frames.

21. The apparatus of claim 20, wherein the at least one M-sequence interleaver is configured to concatenate all long turbo code encoded codeblocks received from the plurality of long turbo encoders for a the group of frames and to subsequently interleave the codeblocks in the group of frames.

22. A method of decoding and de-interleaving a received data signal in a receiver device, the method comprising:

receiving a long turbo encoded and M-sequence interleaved data signal;

de-interleaving the received data signal using a round-robin de-interleaver to generate a plurality of turbo encoded codeblocks;

storing each of the plurality of turbo encoded codeblocks in a corresponding codeblock input buffer;

pseudo-randomly generating an M-sequence state in a maximum length linear feedback shift register;

using the M-sequence state as a memory location address in the codeblock input buffer; and

storing a next available soft bit stored in the codeblock input buffer in a codeblock output buffer at a location corresponding the M-sequence bit memory location address.

23. A method of decoding and de-interleaving a received data signal in a communication system, the method comprising:

receiving a long turbo encoded and M-sequence interleaved data signal;

de-interleaving the received data signal using an M-sequence de-interleaver to generate a plurality of turbo encoded codeblocks; and

decoding each of the plurality of codeblocks using a corresponding plurality of long turbo decoders;

wherein de-interleaving the received data signal using the M-sequence bit de-interleaver comprises;

storing received data signal in an input buffer;

pseudo-randomly generating an M-sequence bit in a maximum length linear feedback shift register;

utilizing the M-sequence bit as a memory location address in the input buffer; and

storing a next available soft bit in the input buffer at a location in an output buffer corresponding to the M-sequence memory location address.

24. An apparatus for use in a communication receiver device, comprising:

means for receiving a long turbo encoded and M-sequence interleaved data signal;

means for de-interleaving the received data signal using a round-robin de-interleaver to generate a plurality of turbo encoded codeblocks;

means for storing each of the plurality of turbo encoded codeblocks in a corresponding codeblock input buffer;

means for pseudo-randomly generating an M-sequence state in a maximum length linear feedback shift register;

means for using the M-sequence state as a memory location address in a codeblock input buffer; and

means for storing a next available a soft bit stored in the codeblock input buffer in a codeblock output buffer at a location corresponding to the M-sequence memory location address.

25. An apparatus for use in a communication receiver device, comprising:

means for receiving a long turbo encoded and M-sequence interleaved data signal;

means for de-interleaving the received data signal using an M-sequence de-interleaver to generate a plurality of turbo encoded codeblocks; and

means for decoding each of the plurality of codeblocks using a corresponding plurality of long turbo decoders;

wherein the means for de-interleaving the received data signal using the M-sequence bit de-interleaver comprises;

means for storing received data signal in an input buffer;

means for reverse pseudo-randomly generating an M-sequence bit in a maximum length linear feedback shift register;

means for utilizing the M-sequence bit as a memory location address in the input buffer;

means for storing a next available soft the bit in the input buffer at a location in an output buffer corresponding to the M-sequence memory location address.

26. An apparatus for use in a communication receiver device, comprising:

a memory; and

a processor coupled to the memory, wherein the processor is configured with software instructions to perform steps comprising;

receiving a long turbo encoded and M-sequence interleaved data signal;

de-interleaving the received data signal using a round-robin de-interleaver scheme to generate a plurality of turbo encoded codeblocks;

storing each of the plurality of turbo encoded codeblocks in a corresponding codeblock input buffer;

reverse pseudo-randomly generating an M-sequence state in a maximum length linear feedback shift register;

using the M-sequence state as a memory location address in the corresponding codeblock input buffer; and

storing a next available soft bit stored in the corresponding codeblock input buffer in a codeblock output buffer at a location corresponding to the M-sequence memory location address.

27. An apparatus for use in a communication receiver device, comprising:

a memory; and

a processor coupled to the memory, wherein the processor is configured with software instructions to perform steps comprising;

receiving a long turbo encoded and M-sequence interleaved data signal;

de-interleaving the received data signal using an M-sequence de-interleaver scheme to generate a plurality of turbo encoded codeblocks;

long turbo decoding each of the plurality of codeblocks;

storing the received data signal in an input buffer;

reverse pseudo-randomly generating an M-sequence bit in a maximum length linear feedback shift register;

utilizing the M-sequence bit as a memory location address in the input buffer; and

storing a next available soft bit in the input buffer at a location in an output buffer corresponding to the M-sequence memory location address.

28. A non-transitory processor-readable storage medium having stored thereon processor-executable software instructions configured to cause a mobile device processor to perform steps comprising:

receiving a long turbo encoded and M-sequence interleaved data signal;

de-interleaving the received data signal using a round-robin de-interleaver scheme to generate a plurality of turbo encoded codeblocks;

storing each of the plurality of turbo encoded codeblocks in a corresponding codeblock input buffer;

pseudo-randomly generating a maximum length M-sequence state in a linear feedback shift register;

using the M-sequence state as a memory location address in the codeblock input buffer; and

storing a next available soft bit stored in the codeblock input buffer in a codeblock output buffer at a location corresponding to the M-sequence memory location address.

29. A non-transitory processor-readable storage medium having stored thereon processor-executable software instructions configured to cause a receiver device processor to perform steps comprising:

receiving a long turbo encoded and M-sequence interleaved data signal;

de-interleaving the received data signal using an M-sequence de-interleaver scheme to generate a plurality of turbo encoded codeblocks;

long turbo decoding each of the plurality of codeblocks;

storing the received data signal in an input buffer;

reverse pseudo-randomly generating an M-sequence bit in a maximum length linear feedback shift register;

utilizing the M-sequence bit as a memory location address in the input buffer; and

storing a next available soft bit in the input buffer at a location in an output buffer corresponding the M-sequence bit memory location address.