Traveling pilots within single user, multiple user, multiple access, and/or MIMO wireless communications

• US 20160013908A1
• Filed: 09/25/2015
• Published: 01/14/2016
• Est. Priority Date: 04/24/2011
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Porat, Ron
• Granted Patent: US 10,396,957 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0232 by interpolation between sounding signals
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2666 Acquisition of further OFDM parameters, e.g. bandwidth, subcarrier spacing, or guard interval length
• CPC Class Codes: H04L 5/0026 Division using four or more dimensions
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Pilot tones are included within symbols (e.g., orthogonal frequency division multiplexing (OFDM) symbols) transmitted between wireless communication devices. The pilot tones occupy fewer than all tone locations in any given symbol, and the pilot tones occupy different respective locations within different symbols. Generally, these traveling pilots are assigned to different respective tone locations in different symbols. In total, the pilot tones did not cover every single tone location within the symbols used to convey information between devices. Considering for example, when pilots occupy fewer than all tone locations, even among multiple symbols, a device may perform interpolation to generate a pilot tone estimate corresponding to a tone location not occupied by pilot tone within any symbol. Also, power or magnitude of the pilot tones themselves may be boosted or amplified relative to power magnitude of other tones within such symbols.

Claims

1. A wireless communication device comprising:

a processor configured to;

select a fast Fourier transform (FFT) structure from a plurality of FFT structures;

generate a plurality of OFDM symbols that includes data and pilots modulated on an occupied subset of a plurality of sub-carriers associated with the FFT structure; and

transmit the plurality of OFDM symbols to another wireless communication device for use by the another wireless communication device to perform channel estimation of a wireless communication channel between the wireless communication device and the another wireless communication device, wherein;

each respective FFT structure of the plurality of FFT structures specifies a respective number of sub-carriers for the respective FFT structure, a respective occupied subset of sub-carriers within the respective number of sub-carriers for the respective FFT structure, and a pilot periodicity of a respective number of symbols associated with a respective pilot pattern for the respective FFT structure;

the plurality of FFT structures includes a first FFT structure, a second FFT structure, and a third FFT structure;

the second FFT structure is double size of the first FFT structure;

the third FFT structure is double size of the second FFT structure;

the first FFT structure has a first pilot periodicity of a first number of symbols; and

the second FFT structure and the third FFT structure both have a second pilot periodicity of a second number of symbols.

2. The wireless communication device of claim 1, wherein:

the first FFT structure is a 128 FFT structure;

the second FFT structure is a 256 FFT structure; and

the third FFT structure is a 512 FFT structure.

3. The wireless communication device of claim 1, wherein:

the plurality of FFT structures includes the first FFT structure, the second FFT structure, the third FFT structure, a fourth FFT structure, and a fifth FFT structure;

the fifth FFT structure is half size of the first FFT structure;

the fourth FFT structure is half size of the fifth FFT structure;

the first FFT structure includes a pilot periodicity of 19 symbols associated with a first pilot pattern;

the fourth FFT structure includes a pilot periodicity of 13 symbols associated with a second pilot pattern; and

the fifth FFT structure includes a pilot periodicity of 14 symbols associated with a third pilot pattern.

4. The wireless communication device of claim 1, wherein:

the plurality of FFT structures includes the first FFT structure, the second FFT structure, the third FFT structure, a fourth FFT structure, and a fifth FFT structure;

the fifth FFT structure is half size of the first FFT structure;

the fourth FFT structure is half size of the fifth FFT structure;

the first FFT structure includes 2 pilots per OFDM symbols associated with a first pilot pattern; and

the second FFT structure includes 4 pilots per OFDM symbols associated with a second pilot pattern.

5. The wireless communication device of claim 1, wherein the processor is further configured to:

select the FFT structure from the plurality of FFT structures during a first time period;

generate the plurality of OFDM symbols that includes the data and the pilots modulated on the occupied subset of the plurality of sub-carriers associated with the FFT structure during the first time period;

transmit the plurality of OFDM symbols to the another wireless communication device for use by the another wireless communication device to perform channel estimation of the wireless communication channel between the wireless communication device and the another wireless communication device during the first time period;

select another FFT structure from the plurality of FFT structures during a second time period;

generate another plurality of OFDM symbols that includes other data and other pilots modulated on another occupied subset of another plurality of sub-carriers associated with the another FFT structure during the second time period; and

transmit the another plurality of OFDM symbols to at least one other wireless communication device for use by the at least one other wireless communication device to perform channel estimation of at least one wireless communication channel between the wireless communication device and the at least one other wireless communication device during the second time period.

6. The wireless communication device of claim 1, wherein the processor is further configured to:

generate the plurality of OFDM symbols based on space time block coding (STBC).

7. The wireless communication device of claim 1 further comprising:

a wireless station (STA), wherein the another wireless communication device includes an access point (AP).

8. The wireless communication device of claim 1 further comprising:

an access point (AP), wherein the another wireless communication device includes a wireless station (STA).

9. A wireless communication device comprising:

a processor configured to;

select a fast Fourier transform (FFT) structure from a plurality of FFT structures;

generate a plurality of OFDM symbols that includes data and pilots modulated on an occupied subset of a plurality of sub-carriers associated with the FFT structure; and

transmit the plurality of OFDM symbols to another wireless communication device for use by the another wireless communication device to perform channel estimation of a wireless communication channel between the wireless communication device and the another wireless communication device, wherein;

each respective FFT structure of the plurality of FFT structures specifies a respective number of sub-carriers for the respective FFT structure, a respective occupied subset of sub-carriers within the respective number of sub-carriers for the respective FFT structure, and a pilot periodicity of a respective number of symbols associated with a respective pilot pattern for the respective FFT structure;

the plurality of FFT structures includes a first FFT structure, a second FFT structure, a third FFT structure, a fourth FFT structure, and a fifth FFT structure;

the first FFT structure is a 32 FFT structure and has a first pilot periodicity of a first number of symbols;

the second FFT structure is a 64 FFT structure and has a second pilot periodicity of a second number of symbols;

the third FFT structure is a 128 FFT structure and has a third pilot periodicity of a third number of symbols;

the fourth FFT structure is a 256 FFT structure and has a fourth pilot periodicity of a fourth number of symbols; and

the fifth FFT structure is a 512 FFT structure and has the fourth pilot periodicity of the fourth number of symbols.

10. The wireless communication device of claim 9, wherein:

the first FFT structure includes a pilot periodicity of 13 symbols associated with a first pilot pattern;

the second FFT structure includes a pilot periodicity of 14 symbols associated with a second pilot pattern; and

the third FFT structure includes a pilot periodicity of 19 symbols associated with a third pilot pattern.

11. The wireless communication device of claim 9, wherein the processor is further configured to:

generate the plurality of OFDM symbols based on space time block coding (STBC).

12. The wireless communication device of claim 9 further comprising:

a wireless station (STA), wherein the another wireless communication device includes an access point (AP).

13. The wireless communication device of claim 9 further comprising:

an access point (AP), wherein the another wireless communication device includes a wireless station (STA).

14. A method for execution by a wireless communication device, the method comprising:

selecting a fast Fourier transform (FFT) structure from a plurality of FFT structures;

generating a plurality of OFDM symbols that includes data and pilots modulated on an occupied subset of a plurality of sub-carriers associated with the FFT structure; and

transmitting, via a communication interface of the wireless communication device, the plurality of OFDM symbols to another wireless communication device for use by the another wireless communication device to perform channel estimation of a wireless communication channel between the wireless communication device and the another wireless communication device, wherein;

each respective FFT structure of the plurality of FFT structures specifies a respective number of sub-carriers for the respective FFT structure, a respective occupied subset of sub-carriers within the respective number of sub-carriers for the respective FFT structure, and a pilot periodicity of a respective number of symbols associated with a respective pilot pattern for the respective FFT structure;

the plurality of FFT structures includes a first FFT structure, a second FFT structure, and a third FFT structure;

the second FFT structure is double size of the first FFT structure;

the third FFT structure is double size of the second FFT structure;

the first FFT structure has a first pilot periodicity of a first number of symbols; and

the second FFT structure and the third FFT structure both have a second pilot periodicity of a second number of symbols.

15. The method of claim 14, wherein:

the first FFT structure is a 128 FFT structure;

the second FFT structure is a 256 FFT structure; and

the third FFT structure is a 512 FFT structure.

16. The method of claim 14, wherein:

the plurality of FFT structures includes the first FFT structure, the second FFT structure, the third FFT structure, a fourth FFT structure, and a fifth FFT structure;

the fifth FFT structure is half size of the first FFT structure;

the fourth FFT structure is half size of the fifth FFT structure;

the first FFT structure includes a pilot periodicity of 19 symbols associated with a first pilot pattern;

the fourth FFT structure includes a pilot periodicity of 13 symbols associated with a second pilot pattern; and

the fifth FFT structure includes a pilot periodicity of 14 symbols associated with a third pilot pattern.

17. The method of claim 14, wherein:

the plurality of FFT structures includes the first FFT structure, the second FFT structure, the third FFT structure, a fourth FFT structure, and a fifth FFT structure;

the fifth FFT structure is half size of the first FFT structure;

the fourth FFT structure is half size of the fifth FFT structure;

the first FFT structure includes 2 pilots per OFDM symbols associated with a first pilot pattern; and

the second FFT structure includes 4 pilots per OFDM symbols associated with a second pilot pattern.

18. The method of claim 14 further comprising:

generating the plurality of OFDM symbols based on space time block coding (STBC).

19. The method of claim 14, wherein the wireless communication device includes a wireless station (STA), wherein the another wireless communication device includes an access point (AP).

20. The method of claim 14, wherein the wireless communication device includes an access point (AP), wherein the another wireless communication device includes a wireless station (STA).