Method, apparatus and computer program product providing soft iterative recursive least squares (RLS) channel estimator

• US 8,578,235 B2
• Filed: 11/15/2012
• Issued: 11/05/2013
• Est. Priority Date: 05/16/2006
• Status: Expired due to Fees

• Current Assignee: Conversant Wireless Licensing S.à.r.l. (f/k/a Core Wireless Licensing S.a.r.l.) (MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management))
• Original Assignee: Conversant Wireless Licensing S.à.r.l. (f/k/a Core Wireless Licensing S.a.r.l.) (MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management))
• Inventors: Kim, Kyeong Jin
• Primary Examiner(s): ABRAHAM, ESAW T
• Application Number:
  US13/677,514
• Publication Number:
  US 20130117623A1
• Time in Patent Office: 355 Days
• Field of Search: 714/752
• US Class Current: 714/752
• CPC Class Codes: H03M 13/1148 Structural properties of the code parity-check or generator matrix
• CPC Class Codes: H03M 13/2972 Serial concatenation using convolutional component codes

Abstract

Disclosed is an apparatus having a detector for an iterative LDPC-coded MIMO-OFDM system, where the detector is configured to use a structured irregular LDPC code in conjunction with a belief propagation algorithm. Also disclosed is an apparatus having a detector for a structured irregular LDPC-coded MIMO-OFDM system, where the detector is configured to use an iterative Recursive Least Squares-based data detection and channel estimation technique. Corresponding methods and computer program products are also disclosed.

Claims

1. A method, comprising:

generating, at a detector, a current APP (a posteriori probability) for a received signal based at least in part on a prior APP and a soft channel estimate, the soft channel estimate calculated based on an iterative RLS (recursive least squares) algorithm that approximates an unknown covariance by incorporating a previous channel estimate and the prior APP; and

determining an extrinsic output for the received signal at a channel decoder based on the current APP to generate soft bit information.

2. The method of claim 1, wherein determining the extrinsic output comprises:

decoding the current APP using a belief propagation algorithm.

3. The method of claim 2, wherein the belief propagation system is a layered belief propagation system.

4. The method of claim 1, wherein the iterative RLS algorithm is suitable for use over a quasi-static channel.

5. The method of claim 1, further comprising detecting the received signal for one of a structured irregular low-density parity-check (LDPC) code multiple-input-multiple-output (MIMO) orthogonal frequency division multiplex (OFDM) system and an iterative LDPC-coded MIMO-OFDM system.

6. An apparatus, comprising:

a detector configured to generate a current APP (a posteriori probability) for a received signal based at least in part on a prior APP and a soft channel estimate;

a channel estimator configured to calculate the soft channel estimate based on an iterative RLS (recursive least squares) algorithm that approximates an unknown covariance by incorporating a previous channel estimate and the prior APP; and

a channel decoder configured to determine an extrinsic output for the received signal based on the current APP to generate soft bit information.

7. The apparatus of claim 6, wherein the channel decoder is further configured to decode the current APP using a belief propagation algorithm.

8. The apparatus of claim 7, wherein the belief propagation system is a layered belief propagation system.

9. The apparatus of claim 6, wherein the iterative RLS algorithm is suitable for use over a quasi-static channel.

10. The apparatus of claim 6, wherein the soft data detector is further configured to detect the received signal for one of a structured irregular low-density parity-check (LDPC) code multiple-input-multiple-output (MIMO) orthogonal frequency division multiplex (OFDM) system and an iterative LDPC-coded MIMO-OFDM system.

11. A computer program product comprising instructions embodied in a non-transitory computer readable medium, the instructions, when executed by one or more processors, causing a receiver to:

generate a current APP (a posteriori probability) for a received signal based at least in part on a prior APP and a soft channel estimate, the soft channel estimate calculated based on an iterative RLS (recursive least squares) algorithm that approximates an unknown covariance by incorporating a previous channel estimate and the prior APP; and

determine an extrinsic output for the received signal based on the current APP to generate soft bit information.

12. The computer program product of claim 11, further comprising instructions, when executed by the one or more processors, causing the receiver to decode the current APP using a belief propagation algorithm.

13. The computer program product of claim 12, wherein the belief propagation system is a layered belief propagation system.

14. The computer program product of claim 11, wherein the iterative RLS algorithm is suitable for use over a quasi-static channel.

15. The computer program product of claim 11, further comprising instructions, when executed by the one or more processors, causing the receiver to detect the received signal for one of a structured irregular low-density parity-check (LDPC) code multiple-input-multiple-output (MIMO) orthogonal frequency division multiplex (OFDM) system and an iterative LDPC-coded MIMO-OFDM system.