Preamble sequence generation method in wireless LAN system

• US 10,454,733 B2
• Filed: 10/05/2015
• Issued: 10/22/2019
• Est. Priority Date: 10/05/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Kilbom, Choi, Jinsoo, Lee, Wookbong, Cho, Hangyu, Kang, Jiwon
• Primary Examiner(s): Bayard, Emmanuel
• Application Number:
  US15/516,773
• Publication Number:
  US 20170310516A1
• Time in Patent Office: 1,478 Days
• Field of Search: 375259-260
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2621 Reduction thereof using phase offsets between subcarriers
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Disclosed is a sequence generation method for: generating a basic sequence structure comprising C₅₂, which is composed of 52 tones, and D₁₂, which is composed of 12 tones; selecting any one among a plurality of phase rotation factors, which are determined in advance for a bandwidth and applied to the basic sequence structure by unit of C₅₂ or C₅₂D₁₂; and generating a sequence inserted into a preamble to be transmitted to a terminal.

Claims

1. A method of transmitting a preamble comprising a sequence, the method performed by an access point (AP) in a wireless local area network (WLAN) system and comprising:

generating, by the AP, a basic sequence structure including one or more C₅₂s and one or more D₁₂s,

wherein each of the one or more C₅₂s is composed of 52 tones, and

wherein each of the one or more D₁₂s is composed of 12 tones and has a non-zero value at an interval of 4 tones;

selecting, by the AP, one phase rotation factor from among a plurality of phase rotation factors predetermined for bandwidths for communication with a user equipment (UE);

generating, by the AP, the sequence based on the basic sequence structure and the selected phase rotation factor,

wherein the selected phase rotation factor is applied to the basic sequence structure in a unit of a C₅₂ or a C₅₂D₁₂; and

transmitting, by the AP, the preamble comprising the generated sequence to the UE.

2. The method of claim 1, wherein the basic sequence structure is configured in the form of a C52D12C52D12C52D12C52.

3. The method of claim 2, wherein the selected phase rotation factor is applied in the unit of the C₅₂D₁₂ to change a phase of each C₅₂D₁₂ of the basic sequence structure, and

wherein the phase rotation factor is only applied in the unit of the C₅₂ to change a phase of the last C₅₂.

4. The method of claim 1, wherein the D₁₂ is {0, 0, 0, 1+j, 0, 0, 0, −

1−

j, 0, 0, 0, −

1−

j}.

5. The method of claim 1, wherein the sequence is generated by adding a 0₅ composed of five consecutive 0s to front of the basic sequence structure and adding a 0₇ composed of seven consecutive 0s, to back of the basic sequence structure.

6. The method of claim 5, wherein, in a case of a 20 MHz bandwidth, the sequence comprising the 0₅ and the 0₇ is used without any change,

wherein, in a case of a 40 MHz bandwidth, a sequence composed of two first partial sequences having a sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 20 MHz bandwidth, one D₁₂, one 0₅, and one 0₇ is used, and

wherein, in a case of a 80 MHz bandwidth, a sequence composed of two second partial sequences having sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 40 MHz bandwidth, one D₁₂, one 0₅, and one 0₇ is used.

7. The method of claim 6, wherein, in the case of the 40 MHz bandwidth, the phase rotation factor changes phases in a unit of the first partial sequence having the sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 20 MHz bandwidth, and

wherein, in the case of the 80 MHz bandwidth, the phase rotation factor changes phases in a unit of the second partial sequence having the sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 40 MHz bandwidth.

8. The method of claim 1, wherein the plurality of the phase rotation factors are generated by multiplying any single phase rotation factor by 1, −

1, i, or −

i, cyclic-shifting the any single phase rotation factor, or arranging the any single phase rotation in reverse order.

9. An access point (AP) for transmitting a preamble comprising sequence in a wireless local area network (WLAN) system, the AP comprising:

a transmitter;

a receiver;

a processor connected to the transmitter and the receiver and configured to generate the sequence,

wherein the processor is configured to;

generate a basic sequence structure including one or more C₅₂s and one or more D₁₂s,

wherein each of the one or more C₅₂s is composed of 52 tones, and

wherein each of the one or more D₁₂s is composed of 12 tones and has a non-zero value at an interval of 4 tones;

select one phase rotation factor from among a plurality of phase rotation factors predetermined for bandwidths for communication with a user equipment (UE);

generate the sequence based on the basic sequence structure and the selected phase rotation factor,

wherein the selected phase rotation factor is applied to the basic sequence structure in a unit of a C₅₂ or a C₅₂D₁₂; and

transmit the preamble comprising the generated sequence to the UE.

10. The AP of claim 9, wherein the basic sequence structure is configured in the form of a C₅₂D₁₂C₅₂D₁₂C₅₂D₁₂C₅₂.

11. The AP of claim 10, wherein the selected phase rotation factor is applied in the unit of the C₅₂D₁₂ to change a phase of each C₅₂D₁₂ of the basic sequence structure, and

wherein the phase rotation factor is only applied in the unit of the C₅₂ to change a phase of the last C₅₂.

12. The AP of claim 9, wherein the D₁₂ is {0, 0, 0, 1×

j, 0, 0, 0, −

1 −

j, 0, 0, 0, −

1 −

j}.

13. The AP of claim 9, wherein the sequence is generated by adding a 0₅ composed of five consecutive 0s to front of the basic sequence structure and adding a 0₇ composed of seven consecutive 0s to back of the basic sequence structure.

14. The AP of claim 13, wherein, in a case of a 20 MHz bandwidth, the sequence comprising the 0₅ and the 0₇ is used without any change,

wherein, a case of a 40 MHz bandwidth, a sequence composed of two first partial sequences having a sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 20 MHz bandwidth, one D12, one 0₅, and one 0₇ is used, and

wherein, in a case of a 80 MHz bandwidth, a sequence composed of two second partial sequences having sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 40 MHz bandwidth, one D₁₂, one 0₅, and one 0₇ is used.

15. The AP of claim 14, wherein, in the case of the 40 MHz bandwidth, the phase rotation factor changes phases in a unit of the first partial sequence having the sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 20 MHz bandwidth, and

wherein, in the case of the 80 MHz bandwidth, the phase rotation factor changes phases in a unit of the second partial sequence having the sequence structure that the 0₅ and the 0₇ are eliminated from the sequence for the 40 MHz bandwidth.

16. The AP of claim 9, wherein the plurality of the phase rotation factors are generated by multiplying any single phase rotation factor by 1, −

1, i, or −

i, cyclic-shifting the any single phase rotation factor, or arranging the any single phase rotation in reverse order.