METHODS AND APPARATUS FOR CONFIGURING A PILOT SYMBOL IN A WIRELESS COMMUNICATION SYSTEM

• US 20070082696A1
• Filed: 09/27/2006
• Published: 04/12/2007
• Est. Priority Date: 07/29/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wang, Michael
• Granted Patent: US 8,391,410 B2
• Time in Patent Office: Days
• US Class Current: 455/550.100
• 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 13/2771 Internal interleaver for turbo codes H03M13/2714 and H03M13/2725 take precedence
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0069 Puncturing patterns
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0083 symbol-by-symbol

Abstract

Methods and apparatus for constructing a pilot symbol for a communication frame transmitted in a wireless communication system, such as an OFDM system, are disclosed. In particular, the methods and apparatus generate at least one pseudo-random noise sequence having at least a predetermined length, where the at least one pseudo-random noise sequence represents a system configuration of a wireless system. A time domain symbol sequence is modulated with the at least one pseudo-random noise sequence to create a timing acquisition pilot symbol. The modulated acquisition pilot symbol is further masked to a prescribed frequency profile and placed in a frame for wireless transmission. Accordingly, different system configurations can be communicated from a transmitter to a receiver with the acquisition pilot symbol modulated with correspondingly different pseudo-random noise sequences, while affording low complexity required to process the acquisition pilot symbol and a minimum peak to average power ratio when using QPSK modulation.

Claims

1. A transmitter comprising:

a pseudo-random noise sequence generator configured to generate a pseudo-random noise sequence that corresponds to predefined system information to be communicated to a receiver;

a modulator configured to construct an acquisition pilot symbol by modulating a time domain symbol sequence with the pseudo-random noise sequence,

a spectrum mask unit configured to mask the acquisition pilot symbol to a prescribed frequency profile; and

an assembly unit configured to place the modulated acquisition pilot symbol in a frame for wireless transmission.

2. A transmitter as defined in claim 1, wherein the time domain symbol sequence utilized by the modulator is a QPSK time domain symbol sequence.

3. A transmitter as defined in claim 1, wherein the pseudo-random noise sequence generator is further configured to generate a plurality of pseudo-random noise sequences where each of the plurality of pseudo-random noise sequences represents a corresponding system information.

4. A transmitter as defined in claim 1, wherein the pseudo-random noise sequence is configured to have a length at least twice the length of the time domain sequence.

5. A transmitter as defined in claim 1, further comprising:

a fast Fourier transform unit configured to convert the acquisition pilot symbol modulated by the modulator to frequency domain for use by the spectrum mask unit.

6. A transmitter as defined in claim 5, further comprising:

an inverse fast Fourier transform unit configured to convert the acquisition pilot symbol to frequency domain after the acquisition pilot symbol has been processed by the spectrum mask unit.

7. A transmitter as defined in claim 1, wherein the pseudo-random noise sequence generator is further configured to generate a C number of pseudo-random noise sequence segments, where each of the c number of pseudo-random noise sequence segments represents a different corresponding particular wireless system configuration of a C number of different wireless system configurations.

8. A transmitter as defined in claim 7, wherein the pseudo-random noise sequence generator is further configured to generate the C number of sequences by:

establishing a maximum length pseudo-random noise sequence having a number of bits as determined by the relationship

$1+\left[{\log }_2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)}\right]$

where N is the length of the time domain symbol sequence and c represents one of the C number of sequences, the maximum length pseudo-random noise sequence having with a length of at least

$2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)};<br><br>$

and

dividing the maximum length pseudo-random noise sequence into c non-overlapping pseudo-random noise segments each having a length 2N.

16. A method as defined in claim 7, wherein generating the C number of pseudo-random noise sequences further includes:

establishing a maximum length pseudo-random noise sequence having a number of bits as determined by the relationship

$1+\left[{\log }_2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)}\right]$

where N is the length of the time domain symbol sequence and c represents one of the C number of sequences, the maximum length pseudo-random noise sequence having with a length of at least

$2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)};<br><br>$

and

dividing the maximum length pseudo-random noise sequence into C non-overlapping PN segments each having a length 2N.

9. A method for constructing an acquisition pilot symbol comprising:

generating at least one pseudo-random noise sequence having at least a predetermined length, where the at least one pseudo-random noise sequence represents a system configuration of a wireless system;

modulating a time domain symbol sequence with the at least one pseudo-random noise sequence to create the acquisition pilot symbol;

masking the acquisition pilot symbol to a prescribed frequency profile; and

placing the modulated and masked acquisition pilot symbol in a frame for wireless transmission.

10. A method as defined in claim 9, wherein the time domain symbol sequence is a QPSK time domain symbol sequence.

11. A method as defined in claim 9, wherein generating the at least one pseudo-random noise sequence includes generating a plurality of pseudo-random noise sequences where each of the plurality of pseudo-random noise sequences represents a corresponding system information.

12. A method as defined in claim 9, wherein the pseudo-random noise sequence is configure to have a length at least twice the length of the time domain sequence.

13. A method as defined in claim 9, further comprising:

converting the modulated acquisition pilot symbol to frequency domain with a fast Fourier transform prior to masking.

14. A method as defined in claim 13, further comprising:

converting the acquisition pilot symbol to frequency domain using a inverse fast Fourier transform after the acquisition pilot symbol has been masked.

15. A method as defined in claim 9, wherein generating the at least one pseudo-random noise sequence includes generating a C number of pseudo-random noise sequence segments, where each of the C number of pseudo-random noise sequence segments represents a different corresponding particular wireless system configuration of a C number of different wireless system configurations.

17. A processor for use in a wireless communication device comprising:

a pseudo-random noise sequence generator configured to generate a pseudo-random noise sequence that corresponds to predefined system information to be communicated to a receiver;

a modulator configured to construct an acquisition pilot symbol by modulating a time domain symbol sequence with the pseudo-random noise sequence,

a spectrum mask unit configured to mask the acquisition pilot symbol to a prescribed frequency profile; and

an assembly unit configured to place the modulated acquisition pilot symbol in a frame for wireless transmission.

18. A processor as defined in claim 17, wherein the time domain symbol sequence utilized by the modulator is a QPSK time domain symbol sequence.

19. A processor as defined in claim 17, wherein the pseudo-random noise sequence generator is further configured to generate a plurality of pseudo-random noise sequences where each of the plurality of pseudo-random noise sequences represents a corresponding system information.

20. A processor as defined in claim 17, wherein the pseudo-random noise sequence is configured to have a length at least twice the length of the time domain sequence.

21. A processor as defined in claim 17, further comprising:

a fast Fourier transform unit configured to convert the acquisition pilot symbol modulated by the modulator to frequency domain for use by the spectrum mask unit.

22. A processor as defined in claim 21, further comprising:

an inverse fast Fourier transform unit configured to convert the acquisition pilot symbol to frequency domain after the acquisition pilot symbol has been processed by the spectrum mask unit.

23. A processor as defined in claim 17, wherein the pseudo-random noise sequence generator is further configured to generate a C number of pseudo-random noise sequence segments, where each of the c number of pseudo-random noise sequence segments represents a different corresponding particular wireless system configuration of a C number of different wireless system configurations.

24. A processor as defined in claim 23, wherein the pseudo-random noise sequence generator is further configured to generate the C number of sequences by:

establishing a maximum length pseudo-random noise sequence having a number of bits as determined by the relationship

$1+\left[{\log }_2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)}\right]$

where N is the length of the time domain symbol sequence and c represents one of the C number of sequences, the maximum length pseudo-random noise sequence having with a length of at least

$2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)};<br><br>$

and

dividing the maximum length pseudo-random noise sequence into C non-overlapping pseudo-random noise segments each having a length 2N.

25. A processor for use in a wireless communication device comprising:

means for generating at least one pseudo-random noise sequence having at least a predetermined length, where the at least one pseudo-random noise sequence represents a system configuration of a wireless system;

means for modulating a time domain symbol sequence with the at least one pseudo-random noise sequence to create the acquisition pilot symbol;

means for masking the acquisition pilot symbol to a prescribed frequency profile; and

means for placing the modulated and masked acquisition pilot symbol in a frame for wireless transmission.

26. A processor as defined in claim 25, wherein the time domain symbol sequence is a QPSK time domain symbol sequence.

27. A processor as defined in claim 25, wherein the means for generating the at least one pseudo-random noise sequence is further configured to generate a plurality of pseudo-random noise sequences where each of the plurality of pseudo-random noise sequences represents a corresponding system information.

28. A processor as defined in claim 25, wherein the means for generating the pseudo-random noise sequence is further configured to generate the pseudo-random noise sequence to have a length at least twice the length of the time domain sequence.

29. A processor as defined in claim 25, further comprising:

means for converting the modulated acquisition pilot symbol to frequency domain with a fast Fourier transform prior to masking.

30. A processor as defined in claim 29, further comprising:

means for converting the acquisition pilot symbol to frequency domain using a inverse fast Fourier transform after the acquisition pilot symbol has been masked.

31. A processor as defined in claim 25, wherein the means for generating the at least one pseudo-random noise sequence is further configured to generate a C number of pseudo-random noise sequence segments, where each of the C number of pseudo-random noise sequence segments represents a different corresponding particular wireless system configuration of a C number of different wireless system configurations.

32. A processor as defined in claim 31, wherein the means for generating the pseudo-random noise sequences if further configured to generate the C number of pseudo-random noise sequences by:

establishing a maximum length pseudo-random noise sequence having a number of bits as determined by the relationship

$1+\left[{\log }_2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)}\right]$

where N is the length of the time domain symbol sequence and c represents on of the C number of sequences, the maximum length PN sequence having with a length of at least

$2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)};<br><br>$

and

dividing the maximum length PN sequence into C non-overlapping PN segments each having a length 2N.

33. A computer-readable medium encoded with a set of instructions, the instructions comprising:

an instruction for generating at least one pseudo-random noise sequence having at least a predetermined length, where the at least one pseudo-random noise sequence represents a system configuration of a wireless system;

an instruction for modulating a time domain symbol sequence with the at least one pseudo-random noise sequence to create the acquisition pilot symbol;

an instruction for masking the acquisition pilot symbol to a prescribed frequency profile; and

an instruction for placing the modulated and masked acquisition pilot symbol in a frame for wireless transmission.

34. A computer-readable medium as defined in claim 33, wherein the time domain symbol sequence is QPSK time domain symbol sequence.

35. A computer-readable medium as defined in claim 33, wherein the instruction for generating the at least one pseudo-random noise sequence includes an instruction for generating a plurality of pseudo-random noise sequences where each of the plurality of pseudo-random noise sequences represents a corresponding system information.

36. A computer-readable medium as defined in claim 33, wherein the pseudo-random noise sequence is configured to have a length at least twice the length of the time domain sequence.

37. A computer-readable medium as defined in claim 33, further comprising:

an instruction for converting the modulated acquisition pilot symbol to frequency domain with a fast Fourier transform prior to masking.

38. A computer readable medium as defined in claim 37, further comprising:

an instruction for converting the acquisition pilot symbol to frequency domain using a inverse fast Fourier transform after the acquisition pilot symbol has been masked.

39. A computer readable medium as defined in claim 37, wherein the instruction for generating the at least one pseudo-random noise sequence includes an instruction for generating a C number of pseudo-random noise sequence segments, where each of the C number of pseudo-random noise sequence segments represents a different corresponding particle wireless system configuration of a C number of different wireless system configurations.

40. A computer readable medium as defined in claim 39, wherein generating the C number of pseudo-random noise sequences further includes:

an instruction for establishing a maximum length pseudo-random noise sequence having a number of bits as determined by the relationship

$1+\left[{\log }_2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)}\right]$

where N is the length of the time domain symbol sequence and c represents one of the C number of sequences, the maximum length PN sequence having with a length of at least

$2<br><br>\underset{c=0}{\overset{C-1}{\sum <br><br>}}<br><br>N^{\left(c\right)};<br><br>$

and

an instruction for dividing the maximum length PN sequence into C non-overlapping PN segments each having a length 2N.