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

• US 10,673,591 B2
• Filed: 08/21/2019
• Issued: 06/02/2020
• Est. Priority Date: 04/24/2011
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Inventors: Porat, Ron
• Primary Examiner(s): Malek, Leila
• Application Number:
  US16/546,714
• Publication Number:
  US 20190379507A1
• Time in Patent Office: 286 Days
• Field of Search: 375260
• 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 communication interface; and

processing circuitry that is coupled to the communication interface, wherein at least one of the communication interface or the processing circuitry is configured to;

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

generate a plurality of orthogonal frequency division multiplexing (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 to be used 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 the FFT structure is selected from;

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

a second FFT structure, larger than the first FFT structure, of the plurality of FFT structures, specifies a second number of the sub-carriers that is different than the first number of sub-carriers, a second occupied subset of sub-carriers within the second number of the sub-carriers for the second FFT structure, and a second pilot periodicity of a second number of symbols associated with a second pilot pattern for the respective FFT; and

a third FFT structure, larger than the second FFT structure, of the plurality of FFT structures, specifies a same pilot periodicity of a number of symbols as the second FFT structure.

2. The wireless communication device of claim 1, the at least one of the communication interface or the processing circuitry 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 to be used 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 to be used 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.

3. The wireless communication device of claim 1, the at least one of the communication interface or the processing circuitry is further configured to:

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

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

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

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

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

6. A wireless communication device comprising:

a communication interface; and

processing circuitry that is coupled to the communication interface, wherein at least one of the communication interface or the processing circuitry is configured to;

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

generate a plurality of orthogonal frequency division multiplexing (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 to be used 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 the FFT structure is selected from;

a first FFT structure of the plurality of FFT structures specifies a first number of sub-carriers, a first occupied subset of sub-carriers within the first number of sub-carriers for the first FFT structure, and a first pilot periodicity of a first number of symbols associated with a first pilot pattern of the first FFT structure and the first FFT structure includes 6 pilots per OFDM symbols associated with the first pilot pattern;

a second FFT structure, larger than the first FFT structure, of the plurality of FFT structures, specifies a second number of the sub-carriers that is different than the first number of sub-carriers, a second occupied subset of sub-carriers within the second number of the sub-carriers for the second FFT structure, and a second pilot periodicity of a second number of symbols associated with a second pilot pattern for the respective FFT and the second FFT structure includes 8 pilots per OFDM symbols associated with the second pilot pattern; and

a third FFT structure, larger than the second FFT structure, of the plurality of FFT structures, specifies a same pilot periodicity of a number of symbols as the second FFT structure and the third FFT structure includes 16 pilots per OFDM symbols associated with the second pilot pattern.

7. A wireless communication device comprising:

a communication interface; and

processing circuitry that is coupled to the communication interface, wherein at least one of the communication interface or the processing circuitry configured to;

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

generate a plurality of orthogonal frequency division multiplexing (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 to be used 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 the FFT structure is selected from;

a first FFT structure, size 2n FFT, of the plurality of FFT structures specifies a first number of sub-carriers, a first occupied subset of sub-carriers within the first number of sub-carriers for the first FFT structure, and a first pilot periodicity of a first number of symbols associated with a first pilot pattern of the first FFT structure, wherein n is a non-zero integer;

a second FFT structure, size 2<sup>n−

1</sup> FFT, the plurality of FFT structures specifies a second number of sub-carriers that is different than the first number of sub-carriers, a second occupied subset of sub-carriers within the second number of sub-carriers for the second FFT structure, and a second pilot periodicity of a second number of symbols associated with a second pilot pattern for the respective FFT; and

a third FFT structure, size 2ⁿ⁺² FFT, specifies a same pilot periodicity and number of symbols as the second FFT structure.

8. The wireless communication device of claim 7, wherein n equals 7.

9. The wireless communication device of claim 8, wherein:

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

the second FFT structure includes the second pilot periodicity having 31 symbols associated with the second pilot pattern; and

the third FFT structure includes a third pilot periodicity having 31 symbols associated with a third pilot pattern.

10. The wireless communication device of claim 7, the at least one of the communication interface or the processing circuitry is further configured to:

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

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

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

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

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

13. A wireless communication device comprising:

a communication interface; and

processing circuitry that is coupled to the communication interface, wherein at least one of the communication interface or the processing circuitry configured to;

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

generate a plurality of orthogonal frequency division multiplexing (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 to be used 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 the FFT structure is selected from;

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

a second FFT structure of the plurality of FFT structures specifies a second number of sub-carriers that is different than the first number of sub-carriers, a second occupied subset of sub-carriers within the second number of sub-carriers for the second FFT structure, and a second pilot periodicity of a second number of symbols associated with a second pilot pattern for the respective FFT;

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

the first FFT structure is a 2ⁿ FFT structure and has the first pilot periodicity of the first number of symbols, wherein n is a non-zero integer;

the second FFT structure is a 2ⁿ⁺¹ FFT structure and has the second pilot periodicity of the second number of symbols;

the third FFT structure is a 2ⁿ⁺² FFT structure and has a third pilot periodicity of a third number of symbols;

the fourth FFT structure is a 2ⁿ⁺³ FFT structure and has a fourth pilot periodicity of a fourth number of symbols; and

the fifth FFT structure is a 2ⁿ⁺⁴ FFT structure and has a same pilot periodicity and number of symbols as the fourth FFT structure.

14. The wireless communication device of claim 13, wherein n equals 5.

15. The wireless communication device of claim 13, wherein:

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

the second FFT structure includes the first pilot periodicity having 14 symbols associated with the first pilot pattern;

the third FFT structure includes the first pilot periodicity having 19 symbols associated with the first pilot pattern;

the fourth FFT structure includes a fourth pilot periodicity having 31 symbols associated with the second pilot pattern; and

the fifth FFT structure includes a fifth pilot periodicity having 31 symbols associated with a third pilot pattern.

16. The wireless communication device of claim 13, wherein:

the first FFT structure includes 26 occupied tones;

the second FFT structure includes 56 occupied tones;

the third FFT structure includes 114 occupied tones;

the fourth FFT structure includes 242 occupied tones; and

the fifth FFT structure includes 484 occupied tones.

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

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

18. The wireless communication device of claim 13, wherein the wireless communication device includes a wireless station (STA), wherein the another wireless communication device includes an access point (AP).

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

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