Method and apparatus for receiving signals in a MIMO system with multiple channel encoders

• US 8,411,806 B1
• Filed: 08/18/2009
• Issued: 04/02/2013
• Est. Priority Date: 09/03/2008
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Lee, Jungwon, Lou, Hui-Ling
• Primary Examiner(s): Payne, David C.
• Assistant Examiner(s): Perez, James M
• Application Number:
  US12/543,363
• Time in Patent Office: 1,323 Days
• Field of Search: 375259-262, 375/316, 375340-341, 375346-350
• US Class Current: 375/341
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04L 1/005 Iterative decoding, including iteration between signal detection and decoding operation
• CPC Class Codes: H04L 1/0055 MAP-decoding
• CPC Class Codes: H04L 1/0631 Receiver arrangements
• CPC Class Codes: H04L 25/03305 Joint sequence estimation and interference removal joint detection of several desired signals H04L25/03331
• CPC Class Codes: H04L 25/03318 Provision of soft decisions
• CPC Class Codes: H04L 25/03891 Spatial equalizers MIMO diversity systems H04B7/0413

Abstract

In a method for decoding plurality of information streams corresponding to a plurality of layers, where the plurality of information streams have been transmitted via a multiple input multiple output (MIMO) communication channel, a plurality of received signals are processed to decode information corresponding to a first layer. A plurality of modified received signals are generated using the decoded information corresponding to the first layer and the plurality of received signals. Bit metric values are generated for a second layer using MIMO maximum likelihood (ML) demodulation and using the plurality of modified received signals and channel and modulation information for interfering signals. Information corresponding to the second layer is decoded using the generated bit metric values.

Claims

1. A method of decoding a plurality of information streams corresponding to a plurality of layers, the plurality of information streams transmitted via a multiple input multiple output (MIMO) communication channel, the method comprising:

performing a first matrix decomposition on a channel matrix;

preprocessing a plurality of received signals with information from the first matrix decomposition;

preprocessing the channel matrix with information from the first matrix decomposition to generate a first modified channel matrix;

processing the plurality of received signals to decode information corresponding to a first layer transmitted via at least one first spatial stream;

generating a plurality of modified received signals using (i) the decoded information corresponding to the first layer and the plurality of received signals and (ii) the first modified channel matrix;

performing a second matrix decomposition on the first modified channel matrix;

preprocessing the plurality of modified received signals with information from the second matrix decomposition;

processing the first modified channel matrix with information from the second matrix decomposition to generate a second modified channel matrix;

generating bit metric values for a second layer using MIMO maximum likelihood (ML) demodulation and using (i) the plurality of modified received signals and (ii) channel and modulation information for interfering signals including the second modified channel matrix, wherein the second layer is transmitted via at least one second spatial stream; and

decoding information corresponding to the second layer using the generated bit metric values.

2. A method according to claim 1, wherein generating the bit metric values for the second layer comprises generating bit metric values corresponding to only one spatial stream.

3. A method according to claim 1, wherein generating the bit metric values for the second layer comprises generating bit metric values corresponding to a plurality of spatial streams.

4. A method according to claim 3, further comprising de-mapping the plurality of spatial streams to a single stream of bit metric values prior to decoding.

5. A method according to claim 1, further comprising de-interleaving the bit metric values prior to decoding.

6. A method according to claim 1, further comprising pre-processing the plurality of modified received signals for space-time coding.

7. A method according to claim 1, further comprising equalizing the plurality of modified received signals using a MIMO equalizer.

8. A method according to claim 1, wherein the bit metric values are log likelihood ratios.

9. A successive interference cancellation receiver for receiving a plurality of information streams transmitted via a multiple input multiple output (MIMO) communication channel, the plurality of information streams corresponding to a plurality of layers, the successive interference cancellation receiver comprising:

a first layer receiver to demodulate and decode a plurality of received signals to decode information corresponding to a first layer transmitted via at least one first spatial stream, wherein the first layer receiver is configured to perform a first matrix decomposition on a channel matrix, preprocess the plurality of received signals with information from the first matrix decomposition, and preprocess the channel matrix with information from the first matrix decomposition to generate a first modified channel matrix;

an interference canceller to cancel interference due to the first layer from the plurality of received signals to generate a plurality of modified received signals, wherein the interference canceller is configured to use the first modified channel matrix to generate the plurality of modified received signals;

a second layer receiver to demodulate and decode the plurality of modified received signals to decode information corresponding to a second layer, wherein (i) the second layer is transmitted via at least one second spatial stream, (ii) the second layer receiver is configured to perform a second matrix decomposition on the first modified channel matrix, preprocess the plurality of modified received signals with information from the second matrix decomposition, and process the first modified channel matrix with information from the second matrix decomposition to generate a second modified channel matrix, and (ii) (iii) the second receiver includes;

a MIMO maximum likelihood (ML) demodulator to generate bit metric values for the second layer using (i) the plurality of modified received signals and (ii) channel and modulation information for interfering signals including the second modified channel matrix, and

a decoder to generate information corresponding to the second layer using the bit metric values.

10. A successive interference cancellation receiver according to claim 9, wherein the second layer receiver further includes a pre-processor for space-time coding.

11. A successive interference cancellation receiver according to claim 9, wherein the second layer receiver further includes a MIMO equalizer.

12. A successive interference cancellation receiver according to claim 9, wherein the second layer receiver further includes a spatial stream de-mapper to de-map the bit metric values.

13. A successive interference cancellation receiver according to claim 9, wherein the second layer receiver further includes a deinterleaver to deinterleave the bit metric values.

14. A successive interference cancellation receiver according to claim 9, wherein the first layer receiver includes:

a MIMO ML demodulator to generate bit metric values for the first layer using (i) the plurality of received signals and (ii) channel and modulation information for interfering signals including the first modified channel matrix; and

a decoder to generate the information corresponding to the first layer using the bit metric values generated by the MIMO ML demodulator of the first receiver.

15. A successive interference cancellation receiver according to claim 9, wherein the bit metric values are log likelihood ratios.

16. A successive interference cancellation receiver for receiving a plurality of information streams transmitted via a multiple input multiple output (MIMO) communication channel, the plurality of information streams corresponding to a plurality of layers, the successive interference cancellation receiver comprising:

a plurality of layer receivers, each layer receiver to demodulate and decode a respective plurality of input signals to obtain information corresponding to a respective one of the plurality of layers, wherein each layer in the plurality of layers is transmitted via at least one respective spatial stream;

one or more interference cancellers, each interference canceller of the one or more interference cancellers to receive an output from a respective one of the plurality of layer receivers and to cancel interference from the plurality of input signals to the respective one of the plurality of layer receivers, the interference due to a respective one of the plurality of layers;

wherein at least one of the plurality of layer receivers comprises;

a MIMO maximum likelihood (ML) demodulator to generate bit metric values for the respective layer using a plurality of signals generated from a first interference canceller of the one or more interference cancellers and channel and modulation information for interfering signals; and

a decoder to generate information corresponding to the respective layer using the bit metric values.

17. A successive interference cancellation receiver according to claim 16, wherein another one of the plurality of layer receivers comprises:

a MIMO ML demodulator to generate bit metric values for the corresponding layer using a plurality of received signals and channel and modulation information for interfering signals; and

a decoder to generate information corresponding to the respective layer using the bit metric values.

18. A successive interference cancellation receiver according to claim 16, wherein the at least one layer receiver further includes a pre-processor for space-time coding.

19. A successive interference cancellation receiver according to claim 16, wherein the at least one layer receiver further includes a MIMO equalizer.

20. A successive interference cancellation receiver according to claim 16, wherein the at least one layer receiver further includes a spatial stream de-mapper to de-map the bit metric values.

21. A successive interference cancellation receiver according to claim 16, wherein the at least one layer receiver further includes a deinterleaver to deinterleave the bit metric values.