Quadratic polynomial permutation (QPP) interleaver providing hardware savings and flexible granularity adaptable to any possible turbo code block size

• US 20080172590A1
• Filed: 06/07/2007
• Published: 07/17/2008
• Est. Priority Date: 01/17/2007
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Shen, Ba-Zhong, Lee, Tak K.
• Granted Patent: US 7,975,203 B2
• Time in Patent Office: Days
• US Class Current: 714/755
• CPC Class Codes: H03M 13/2757 Interleaver with an interleaving rule not provided for in the subgroups H03M13/2703 - H03M13/2753
• CPC Class Codes: H03M 13/2775 Contention or collision free turbo code internal interleaver
• CPC Class Codes: H03M 13/2957 Turbo codes and decoding
• CPC Class Codes: H03M 13/3972 using sliding window techniques or parallel windows
• CPC Class Codes: H03M 13/6356 by repetition or insertion of dummy data, i.e. rate reduction
• CPC Class Codes: H03M 13/6362 by puncturing
• CPC Class Codes: H03M 13/6508 Flexibility, adaptability, parametrability and configurability of the implementation
• CPC Class Codes: H03M 13/6525 3GPP LTE including E-UTRA
• CPC Class Codes: H03M 13/6566 Implementations concerning memory access contentions

Abstract

Quadratic polynomial permutation (QPP) interleaver providing hardware saving and flexible granularity adaptable to any possible turbo code block size. A means is presented by which only a very small number of coefficients need be stored to effectuate a wide variety of QPP interleaves as can be employed in the context of turbo coding. In one instance, to accommodate the approximate 6000 different turbo code block sizes in 3GPP LTE channel coding, only 5 different coefficient values need to be stored to effectuate a very broad range of QPP interleaves to be applied each of those various turbo code block sizes. Moreover, a few small number of dummy bits, if any, need to be employed to accommodate a very broad range of turbo code block sizes. It is noted that the QPP interleaving as described herein can be applied to turbo encoding and turbo decoding (e.g., including both interleaving and de-interleaving).

Claims

1. A turbo encoder having selectable interleaving, the turbo encoder comprising:

a first constituent encoder that is operable to encode an information block thereby generating a first encoded plurality of bits;

a selectable interleaver module that is operable to;

employ one selected quadratic polynomial permutation (QPP) interleave of a plurality of QPP interleaves to interleave the information block;

interleave any sized turbo code block within a predetermined turbo code block size range that is divided into k sub-ranges, where k is an integer; and

employ a plurality of coefficients to effectuate each QPP interleave of the plurality of QPP interleaves, the plurality of coefficients including k+1 coefficients; and

a second constituent encoder that is operable to encode the interleaved information block thereby generating a second encoded plurality of bits; and

wherein;

bits that are alternatively selected from the first encoded plurality of bits and the second encoded plurality of bits form an encoded block;

the alternatively selected bits undergo modulation to generate a turbo coded signal that comports with a communication channel; and

the turbo coded signal is launched into the communication channel.

2. The turbo encoder of claim 1, further comprising:

a dummy bit module that is selectively operable to modify the information block by adding a dummy bit to the information block based on the size of the information block.

3. The turbo encoder of claim 1, wherein:

the turbo encoder is implemented in a first communication device;

the first communication device is a coupled to a second communication device via the communication channel;

the second communication device is operable to receive the turbo coded signal from the communication channel; and

the second communication device includes a plurality of turbo decoders implemented to perform parallel decoding processing of the turbo coded signal.

4. The turbo encoder of claim 1, wherein:

the turbo encoder is coupled to a turbo decoder via the communication channel;

the turbo decoder is operable to receive the turbo coded signal from the communication channel;

the turbo decoder is operable to perform selectable interleaving and de-interleaving when decoding turbo coded signal, the turbo decoder includes;

a first soft-in/soft-out (SISO) decoder that is operable to perform SISO decoding on a plurality of metrics associated with the turbo coded signal thereby calculating first extrinsic information;

at least one additional selectable interleaver module that is operable to employ one selected QPP interleave to perform interleaving on the first extrinsic information thereby generating first “

a priori probability”

(app) information;

a second SISO decoder that is operable to perform SISO decoding on the first app information thereby generating second extrinsic information;

a selectable de-interleaver module that is operable to employ one selected QPP de-interleave to perform de-interleaving on the second extrinsic information thereby generating second app information; and

an output processor that is operable to process most recent extrinsic information that has been generated by the second SISO decoder thereby generating a best estimate of at least one information bit encoded within the turbo coded signal.

5. The turbo encoder of claim 1, wherein:

the turbo encoder is implemented in a first communication device;

the first communication device is a coupled to a second communication device via the communication channel;

the second communication device is operable to receive the turbo coded signal from the communication channel;

the second communication device includes a turbo decoder that is operable to perform decoding processing of the turbo coded signal thereby generating a best estimate of at least one information bit encoded within the turbo coded signal; and

the turbo decoder is operable to employ the one selected QPP interleave and a QPP de-interleave that corresponds to the one selected quadratic polynomial permutation (QPP) interleave when performing decoding processing of the turbo coded signal.

6. The turbo encoder of claim 1, wherein:

one coefficient within the plurality of coefficients is a prime number.

7. The turbo encoder of claim 1, wherein:

the selectable interleaver module is operable to generate the one selected QPP interleave of the plurality of QPP interleaves in real time using a closed formula that employs the k+1 coefficients.

8. The turbo encoder of claim 1, wherein:

the turbo encoder is implemented within a wireless personal communication device.

9. The turbo encoder of claim 1, wherein:

the turbo encoder is implemented within a communication device; and

the communication device is implemented within a wireless communication system.

10. The turbo encoder of claim 1, wherein:

the turbo encoder is implemented within a communication device; and

the communication device is implemented within at least one of a satellite communication system, a wireless communication system, a wired communication system, and a fiber-optic communication system.

11. A turbo encoder having selectable interleaving, the turbo encoder comprising:

a dummy bit module that is selectively operable to modify an information block by adding a dummy bit to the information block based on the size of the information block thereby generating a modified information block;

a first constituent encoder that is operable to encode the modified information block thereby generating a first encoded plurality of bits;

a selectable interleaver module that is operable to;

employ one selected quadratic polynomial permutation (QPP) interleave of a plurality of QPP interleaves to interleave the modified information block;

interleave any sized turbo code block or modified information block within a predetermined turbo code block size range that is divided into k sub-ranges, where k is an integer; and

employ a plurality of coefficients to effectuate each QPP interleave of the plurality of QPP interleaves, the plurality of coefficients including k+1 coefficients; and

a second constituent encoder that is operable to encode the interleaved information block or modified interleaved information block thereby generating a second encoded plurality of bits; and

wherein;

bits that are alternatively selected from the first encoded plurality of bits and the second encoded plurality of bits form an encoded block;

the alternatively selected bits undergo modulation to generate a turbo coded signal that comports with a communication channel;

the turbo coded signal is launched into the communication channel; and

the selectable interleaver module is operable to generate the one selected QPP interleave of the plurality of QPP interleaves in real time using a closed formula that employs the k+1 coefficients.

12. The turbo encoder of claim 11, wherein:

the turbo encoder is implemented in a first communication device;

the first communication device is a coupled to a second communication device via the communication channel;

the second communication device is operable to receive the turbo coded signal from the communication channel; and

the second communication device includes a plurality of turbo decoders implemented to perform parallel decoding processing of the turbo coded signal.

13. The turbo encoder of claim 11, wherein:

the turbo encoder is coupled to a turbo decoder via the communication channel;

the turbo decoder is operable to receive the turbo coded signal from the communication channel;

the turbo decoder is operable to perform selectable interleaving and de-interleaving when decoding turbo coded signal, the turbo decoder includes;

a first soft-in/soft-out (SISO) decoder that is operable to perform SISO decoding on a plurality of metrics associated with the turbo coded signal thereby calculating first extrinsic information;

at least one additional selectable interleaver module that is operable to employ one selected QPP interleave to perform interleaving on the first extrinsic information thereby generating first “

a priori probability”

(app) information;

a second SISO decoder that is operable to perform SISO decoding on the first app information thereby generating second extrinsic information;

a selectable de-interleaver module that is operable to employ one selected QPP de-interleave to perform de-interleaving on the second extrinsic information thereby generating second app information; and

an output processor that is operable to process most recent extrinsic information that has been generated by the second SISO decoder thereby generating a best estimate of at least one information bit encoded within the turbo coded signal.

14. The turbo encoder of claim 11, wherein:

the turbo encoder is implemented in a first communication device;

the first communication device is a coupled to a second communication device via the communication channel;

the second communication device is operable to receive the turbo coded signal from the communication channel;

the second communication device includes a turbo decoder that is operable to perform decoding processing of the turbo coded signal thereby generating a best estimate of at least one information bit encoded within the turbo coded signal; and

the turbo decoder is operable to employ the one selected QPP interleave and a QPP de-interleave that corresponds to the one selected quadratic polynomial permutation (QPP) interleave when performing decoding processing of the turbo coded signal.

15. The turbo encoder of claim 11, wherein:

the turbo encoder is implemented within a communication device; and

the communication device is implemented within a wireless communication system.

16. The turbo encoder of claim 11, wherein:

the turbo encoder is implemented within a communication device; and

the communication device is implemented within at least one of a satellite communication system, a wireless communication system, a wired communication system, and a fiber-optic communication system.

17. A method for turbo encoding at least one information bit using selectable quadratic polynomial permutation (QPP) interleaving, the method comprising:

selectively modifying an information block by adding a dummy bit to the information block based on the size of the information block thereby generating a modified information block;

employing a first constituent encoder to encode the information block or the modified information block thereby generating a first encoded plurality of bits;

employing one selected QPP interleave of a plurality of QPP interleaves to interleave the information block or the modified information block;

employing a plurality of coefficients to effectuate each QPP interleave of the plurality of QPP interleaves, the plurality of coefficients including k+1 coefficients;

employing a second constituent encoder to encode the interleaved information block or the or the interleaved modified information block thereby generating a second encoded plurality of bits;

alternatively selecting bits from the first encoded plurality of bits and the second encoded plurality of bits to form an encoded block;

modulating the encoded block to generate a turbo coded signal that comports with a communication channel; and

launching the turbo coded signal into the communication channel.

18. The method of claim 17, further comprising:

generating the one selected QPP interleave of the plurality of QPP interleaves in real time using a closed formula that employs the k+1 coefficients.

19. The method of claim 17, wherein:

the method is performed within a turbo encoder;

the turbo encoder is implemented within a communication device; and

the communication device is implemented within a wireless communication system.

20. The method of claim 17, wherein:

the method is performed within a turbo encoder;

the turbo encoder is implemented within a communication device; and

the communication device is implemented within at least one of a satellite communication system, a wireless communication system, a wired communication system, and a fiber-optic communication system.