Method and apparatus of transmitting PLCP header for sub 1 GHz communication

Patent metadata

Field	Value
Publication number	US-8948284-B2
Application number	US-201213670324-A
Country	US
Kind code	B2
Filing date	Nov 6, 2012
Priority date	Nov 7, 2011
Publication date	Feb 3, 2015
Grant date	Feb 3, 2015

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).

First claim

What is claimed is:

1. A method of transmitting training fields for wireless local area network, the method comprising:
determining a short training field (STF) sequence and a number of at least one first orthogonal frequency division multiplexing (OFDM) symbol for the STF sequence based on a size of a channel bandwidth in a sub 1 GHz frequency band;
determining a long training field (LTF) sequence and a number of at least one second OFDM symbol for the LTF sequence based on the size of the channel bandwidth in the sub 1 GHz frequency band;
transmitting the STF sequence on the at least one first OFDM symbol; and
transmitting the LTF sequence on the at least one second OFDM symbol,
wherein the size of the channel bandwidth is 1 MHz, 2 MHz, 4 MHz, 8 MHz, 16 MHz or 8+8 MHz in the sub 1 GHz frequency band, and
wherein the at least one first OFDM symbol and the at least one second OFDM symbol are 1/10 down-clocked OFDM symbols having a duration of 40 micro-second.

2. The method of claim 1 ,
wherein the LTF sequence is the sequence of alternating 0 s and ±1 s if the size of the channel bandwidth is equal to or greater than 2 MHz,
wherein the LTF sequence transformed based on the inverse discrete Fourier transform (IDFT) is a waveform having a self-repeated pattern in the time domain if the size of the channel bandwidth is equal to or greater than 2 MHz,
wherein the STF sequence transformed based on the IDFT is a waveform having a 5 times-repeated pattern in a time domain if the size of the channel bandwidth is equal to or greater than 2 MHz,
wherein the number of the at least one first OFDM symbols is one if the size of the channel bandwidth is equal to or greater than 2 MHz, and
wherein the number of the at least one second OFDM symbol is one if the size of the channel bandwidth is equal to or greater than 2 MHz.

3. The method of claim 2 ,
wherein if the size of the channel bandwidth is equal to or greater than 2 MHz, the LTF sequence VHTLTF −28,28 is defined by {0, 1, LTF left , 0, LTF right , −1, 0, 1}, where 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} and 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}.

4. The method of claim 3 ,
wherein the STF sequence transformed based on the IDFT is a waveform having a 5 times-repeated pattern in a time domain if the size of the channel bandwidth is 1 MHz,
the number of the at least one first OFDM symbols is one if the size of the channel bandwidth is 1 MHz,
the number of the at least one second OFDM symbols is two if the size of the channel bandwidth is 1 MHz.

5. A wireless device transmitting a training field for wireless local area network, the wireless device comprising:
a radio frequency (RF) unit configured to transmit or receive a radio signal; and
a processor operatively coupled with the RF unit and configured to:
determine a short training field (STF) sequence, a number of at least one first orthogonal frequency division multiplexing (OFDM) symbol for the STF sequence based on a size of a channel bandwidth in a sub 1 GHz frequency band;
determine a long training field (LTF) sequence, a number of at least one second OFDM symbol for the LTF sequence based on the size of the channel bandwidth in the sub 1 GHz frequency band;
instruct the RF unit to transmit the STF sequence on the at least one first OFDM symbol; and
instruct the RF unit to transmit the LTF sequence on the at least one second OFDM symbol,
wherein the size of the channel bandwidth is 1 MHz, 2 MHz, 4 MHz, 8 MHz, 16 MHz or 8+8 MHz in the sub 1 GHz frequency band, and
wherein the at least one first OFDM symbol and the at least one second OFDM symbol are 1/10 down-clocked OFDM symbols having a duration of 40 micro-second.

6. The wireless device of claim 5 ,
wherein the LTF sequence is the sequence of alternating 0 s and ±1 s if the size of the channel bandwidth is equal to or greater than 2 MHz,
wherein the LTF sequence transformed based on the inverse discrete Fourier transform (IDFT) is a waveform having a self-repeated pattern in the time domain if the size of the channel bandwidth is equal to or greater than 2 MHz,
wherein the STF sequence transformed based on the IDFT is a waveform having a 5 times-repeated pattern in a time domain if the size of the channel bandwidth is equal to or greater than 2 MHz,
wherein the number of the at least one first OFDM symbols is one if the size of the channel bandwidth is equal to or greater than 2 MHz, and
wherein the number of the at least one second OFDM symbol is one if the size of the channel bandwidth is equal to or greater than 2 MHz.

7. The wireless device of claim 6 ,
wherein if the size of the channel bandwidth is equal to or greater than 2 MHz, the LTF sequence VHTLTF −28,28 is defined by {0, 1, LTF left , 0, LTF right , −1, 0, 1}, where 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} and 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}.

8. The wireless device of claim 7 ,
wherein the STF sequence transformed based on the IDFT is a waveform having a 5 times-repeated pattern in a time domain if the size of the channel bandwidth is 1 MHz,
wherein the number of the at least one first OFDM symbols is one if the size of the channel bandwidth is 1 MHz, and
wherein the number of the at least one second OFDM symbols is two if the size of the channel bandwidth is 1 MHz.

Assignees

• Lg Electronics Inc
• Lg Electronics Inc

Inventors

• Park Jong Hyun
• Kim Eun Sun
• Yi Yun Jung
• Sohn Ill Soo
• Kim Bong Hoe

Classifications

• H04L27/2613 Primary

  Structure of the reference signals · CPC title

• H04L27/26132

  using repetition · CPC title