METHOD AND APPARATUS OF TRANSMITTING PLCP HEADER FOR SUB 1 GHZ COMMUNICATION

• US 20130114757A1
• Filed: 11/06/2012
• Published: 05/09/2013
• Est. Priority Date: 11/07/2011
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: PARK, Jong Hyun, KIM, Eun Sun, SOHN, Ill Soo, KIM, Bong Hoe, YI, Yun Jung
• Granted Patent: US 8,948,284 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04L 27/2613 Structure of the reference signals

Abstract

Method and apparatus of transmitting PLCP header for sub 1 GHz communication is disclosed. A method of transmitting a physical layer convergence protocol(PLCP) header may comprise generating a short training field (STF) sequence over 1 orthogonal frequency division multiplexing (OFDM) symbol, transforming the STF sequence to repeated waveform patterns in time domain and transmitting the PLCP header comprising the STF sequence, wherein the STF sequence may be a sequence transformed to repeated waveform patterns in time domain by inverse discrete Fourier transform (IDFT).

Claims

1. A method of transmitting a physical layer convergence protocol(PLCP) header, the method comprising:

generating a short training field (STF) sequence over 1 orthogonal frequency division multiplexing (OFDM) symbol;

transforming the STF sequence to repeated waveform patterns in time domain; and

transmitting the PLCP header comprising the STF sequence,

wherein the STF sequence is a sequence transformed to repeated waveform patterns in time domain by inverse discrete Fourier transform (IDFT).

2. The method of claim 1, wherein the STF sequence S₋

26,26 is

S<sub>−

26,26</sub>=√

{square root over (½

)}{0, 0, 1+j, 0, 0, 0, −

1−

j, 0, 0, 0, 1+j, 0, 0, 0, −

1−

j, 0, 0, 0, −

1−

j, 0, 0, 0, 1+j, 0, 0, 0, 0, 0, 0, 0, −

1−

j, 0, 0, 0, −

1−

j, 0, 0, 0, 1+j, 0, 0, 0, 1+j, 0, 0, 0, 1+j, 0, 0, 0, 1+j, 0, 0}

; and

wherein each value in the STF sequence is sequentially applied to each subcarrier having index value integer in the range −

26≦

k≦

26.

3. The method of claim 1, further comprising:

generating a long training field (LTF) sequence over 1 OFDM symbol; and

transmitting the PLCP header further comprising the LTF sequence,

wherein the LTF sequence VHTLTF<sub>−

28,28</sub> is a sequence having a zero tone between non-zero tones.

4. The method of claim 3, wherein VHTLTF₋

28,28 is

VHTLTF<sub>−

28,28</sub>={0, 1, LTF_left, 0, LTF_right, −

1, 0, 1}

LTF_left={0, 1, 0, −

1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, −

1, 0, 1, 0, −

1, 0, −

1, 0, 1, 0, 1}

LTF_right={1, 0, −

1, 0, 1, 0, 1, 0, 1, 0, −

1, 0, −

1, 0, 1, 0, −

1, 0, 1, 0, 1, 0, 1, 0, 1, 0}

; and

wherein each value in the LTF sequence is sequentially applied to each subcarrier having index value integer in the range −

28≦

k≦

28.

5. The method of claim 4, further comprising:

determining the number of the OFDM symbol used to transmit the STF sequence depend on a transmission bandwidth; and

determining the number of the OFDM symbol used to transmit the LTF sequence depend on the transmission bandwidth.

6. The method of claim 5, further comprising:

boosting transmission power to transmit the STF sequence when the transmission bandwidth is 1 MHz.

7. The method of claim 1, wherein the PLCP header is 1/10 downclocked PLCP header, 1/10 downclocked PLCP header transmitted over OFDM symbols having 40 micro second duration per one OFDM symbol.

8. A wireless device configured to transmit physical layer convergence protocol (PLCP) header, the wireless device comprising a processor configured to generate a STF (short training field) sequence over 1 orthogonal frequency division multiplexing (OFDM) symbol;

transform the STF sequence to repeated waveform patterns in time domain; and

transmit the PLCP header comprising the STF sequence,

wherein the STF sequence is a sequence transformed to repeated waveform patterns in time domain by inverse discrete Fourier transform (IDFT).

9. The wireless device of claim 8, wherein the STF sequence S₋

26,26 is

S<sub>−

26,26</sub>=√

{square root over (½

)}{0, 0, 1+j, 0, 0, 0, −

1−

j, 0, 0, 0, 1+j, 0, 0, 0, −

1−

j, 0, 0, 0, −

1−

j, 0, 0, 0, 1+j, 0, 0, 0, 0, 0, 0, 0, −

1j, 0, 0, 0, −

1−

j, 0, 0, 0, 1+j, 0, 0, 0, 1+j, 0, 0, 0, 1+j, 0, 0, 0, 1+j, 0, 0}

; and

wherein each value in the STF sequence is sequentially applied to each subcarrier having index value integer in the range −

26≦

k≦

26.

10. The wireless device of claim 8, wherein the processor is further configured to:

generate a long training field (LTF) sequence over 1 OFDM symbol; and

transmit the PLCP header further comprising the LTF sequence,

wherein the LTF sequence VHTLTF<sub>−

28,28</sub> is a sequence having a zero tone between non-zero tones.

11. The wireless device of claim 10, wherein VHTLTF₋

28,28 is

VHTLTF<sub>−

28,28</sub>={0, 1, LTF_left, 0, LTF_right, −

1, 0, 1}

LTF_left={0, 1, 0, −

1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, −

1, 0, 1, 0, −

1, 0, −

1, 0, 1, 0, 1}

LTF_right={1, 0, −

1, 0, 1, 0, 1, 0, 1, 0, −

1, 0, −

1, 0, 1, 0, −

1, 0, 1, 0, 1, 0, 1, 0, 1, 0}

; and

wherein each value in the LTF sequence is sequentially applied to each subcarrier having index value integer in the range −

28≦

k≦

28.

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

determine the number of the OFDM symbol used to transmit the STF sequence depend on a transmission bandwidth; and

determine the number of the OFDM symbol used to transmit the LTF sequence depend on the transmission bandwidth.

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

boost transmission power to transmit the STF sequence when the transmission bandwidth is 1 MHz.

14. The wireless device of claim 8, wherein the PLCP header is 1/10 downclocked PLCP header, 1/10 downclocked PLCP header transmitted over OFDM symbols having 40 micro second duration per one OFDM symbol.