Auto-detection of repeated signals

• US 9,674,011 B1
• Filed: 02/05/2016
• Issued: 06/06/2017
• Est. Priority Date: 02/10/2015
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Zhang, Hongyuan, Sun, Yakun, Xu, Mingguang
• Primary Examiner(s): Puente, Eva
• Application Number:
  US15/017,343
• Time in Patent Office: 487 Days
• Field of Search: 375341, 375342, 375136
• CPC Class Codes: H04L 25/03012 operating in the time domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04L 25/03171 Arrangements involving maximum a posteriori probability [MAP] detection
• CPC Class Codes: H04L 25/061 providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset removal of dc offset in coupling arrangements H04L25/029, H04L25/0296
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Systems and techniques relating to repeated signal detection are described. A described technique includes receiving a signal including a first portion and a second portion, the first portion including a first received symbol and a second received symbol; detecting whether the first received symbol is repeated as the second received symbol using a maximum a posterior decision metric including a first component and a second component, the first component contributing to the decision metric in accordance with the first received symbol being repeated as the second received symbol, and the second component contributing to the decision metric in accordance with the first received symbol not being repeated as the second received symbol; determining a format based on whether or not the first received symbol was repeated; and processing the second portion of the signal in accordance with the format, as determined.

Claims

1. A method comprising:

receiving a signal comprising a first portion and a second portion, the first portion comprising a first received symbol and a second received symbol;

detecting whether the first received symbol is repeated as the second received symbol using a maximum a posterior decision metric comprising a first component and a second component, wherein the first component contributes to the decision metric in accordance with the first received symbol being repeated as the second received symbol, and the second component contributes to the decision metric in accordance with the first received symbol not being repeated as the second received symbol;

determining a format based on whether or not the first received symbol was repeated; and

processing the second portion of the signal in accordance with the format, as determined.

2. The method of claim 1, wherein the detecting comprises:

selecting a first known symbol from a group of known symbols that maximizes the first component; and

selecting a pair of second known symbols, both being different from each other, from the group of known symbols that maximizes the second component.

3. The method of claim 1, comprising:

determining an equalized version of the first received symbol based on a first wireless channel matrix associated with the first received symbol to produce a first equalized symbol; and

determining an equalized version of the second received symbol based on a second wireless channel matrix associated with the second received symbol to produce a second equalized symbol,

wherein the detecting comprises using the first equalized symbol and the second equalized symbol.

4. The method of claim 3, comprising:

determining an average noise power among tones of the first received symbol and tones of the second received symbol, wherein the average noise power is applied within the first component and the second component.

5. The method of claim 1, comprising:

determining a detection threshold parameter based on one or more channel matrices and one or more minimal distances between points within a symbol constellation, wherein the detecting comprises making a comparison between the decision metric and the detection threshold parameter.

6. The method of claim 1, comprising:

determining a first hard decision output based on a combination of the first received symbol and the second received symbol, the first component being based on the first hard decision output; and

determining second hard decision outputs respectively based on the first received symbol and the second received symbol, the second component being based on the second hard decision outputs.

7. The method of claim 1, comprising:

collecting, in a time domain, first samples associated with the first received symbol; and

collecting, in the time domain, second samples associated with the second received symbol,

wherein the detecting comprises determining the first component based on a summation of products between the first samples and the second samples, and determining the second component based on normalized versions of the first samples and normalized versions of the second samples.

8. A device comprising:

a receiver configured to receive a signal comprising a first portion and a second portion, the first portion comprising a first received symbol and a second received symbol; and

a processor coupled with the receiver, wherein the processor is configured to determine whether the first received symbol is repeated as the second received symbol using a maximum a posterior decision metric comprising a first component and a second component, wherein the first component contributes to the decision metric in accordance with the first received symbol being repeated as the second received symbol, and the second component contributes to the decision metric in accordance with the first received symbol not being repeated as the second received symbol, wherein the processor is configured to determine a format based on whether or not the first received symbol was repeated and process the second portion of the signal in accordance with the format, as determined.

9. The device of claim 8, wherein the processor is configured to select a first known symbol from a group of known symbols that maximizes the first component, and select a pair of second known symbols, both being different from each other, from the group of known symbols that maximizes the second component.

10. The device of claim 8, wherein the processor is configured to determine an equalized version of the first received symbol based on a first wireless channel matrix associated with the first received symbol to produce a first equalized symbol, wherein the processor is configured to determine an equalized version of the second received symbol based on a second wireless channel matrix associated with the second received symbol to produce a second equalized symbol, wherein the processor is configured to use the first equalized symbol and the second equalized symbol to determine whether the first received symbol is repeated as the second received symbol.

11. The device of claim 10, wherein the processor is configured to determine an average noise power among tones of the first received symbol and tones of the second received symbol, wherein the average noise power is applied within the first component and the second component.

12. The device of claim 8, wherein the processor is configured to determine a detection threshold parameter based on one or more channel matrices and one or more minimal distances between points within a symbol constellation, and make a comparison between the decision metric and the detection threshold parameter.

13. The device of claim 8, wherein the processor is configured to determine a first hard decision output based on a combination of the first received symbol and the second received symbol, the first component being based on the first hard decision output, wherein the processor is configured to determine second hard decision outputs respectively based on the first received symbol and the second received symbol, the second component being based on the second hard decision outputs.

14. The device of claim 8, wherein the processor is configured to collect, in a time domain, first samples associated with the first received symbol, and collect, in the time domain, second samples associated with the second received symbol, and wherein the processor is configured to determine the first component based on a summation of products between the first samples and the second samples, and determine the second component based on normalized versions of the first samples and normalized versions of the second samples.

15. A system comprising:

circuitry to receive a signal comprising a first portion and a second portion, the first portion comprising a first received symbol and a second received symbol;

a detector that is configured to determine whether the first received symbol is repeated as the second received symbol using a maximum a posterior decision metric comprising a first component and a second component, wherein the first component contributes to the decision metric in accordance with the first received symbol being repeated as the second received symbol, and the second component contributes to the decision metric in accordance with the first received symbol not being repeated as the second received symbol; and

a decoder that is configured to process the second portion of the signal in accordance with a format determined based on whether or not the first received symbol was repeated.

16. The system of claim 15, wherein the detector is configured to select a first known symbol from a group of known symbols that maximizes the first component, and select a pair of second known symbols, both being different from each other, from the group of known symbols that maximizes the second component.

17. The system of claim 15, wherein the detector is configured to determine an equalized version of the first received symbol based on a first wireless channel matrix associated with the first received symbol to produce a first equalized symbol, wherein the detector is configured to determine an equalized version of the second received symbol based on a second wireless channel matrix associated with the second received symbol to produce a second equalized symbol, wherein the detector is configured to use the first equalized symbol and the second equalized symbol to determine whether the first received symbol is repeated as the second received symbol.

18. The system of claim 15, wherein the detector is configured to determine a detection threshold parameter based on one or more channel matrices and one or more minimal distances between points within a symbol constellation, and make a comparison between the decision metric and the detection threshold parameter.

19. The system of claim 15, wherein the detector is configured to determine a first hard decision output based on a combination of the first received symbol and the second received symbol, the first component being based on the first hard decision output, wherein the detector is configured to determine second hard decision outputs respectively based on the first received symbol and the second received symbol, the second component being based on the second hard decision outputs.

20. The system of claim 15, wherein the detector is configured to collect, in a time domain, first samples associated with the first received symbol, and collect, in the time domain, second samples associated with the second received symbol, and wherein the detector is configured to determine the first component based on a summation of products between the first samples and the second samples, and determine the second component based on normalized versions of the first samples and normalized versions of the second samples.