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How to Generate the preamble(short and long) for 802.11n with 40Mhz - FFT 128 - 64QAM

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matthew989

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Given the information, I have and study. I know for Generate preamble signal "802.11a/g with 20 Mhz - FFT size 64 point -16QAM". For example, like this:
For short preamble
Code:
S1 = [1+1i 0 0 0 -1-1i 0 0 0 1+1i 0 0 0 -1-1i 0 0 0 -1-1i 0 0 0 1+1i 0 0 0 0 0 0 0 -1-1i 0 0 0 -1-1i 0 0 0 1+1i 0 0 0 1+1i 0 0 0 1+1i 0 0 0  1+1i 0 0 0 0 0 0 0];             
S1 = sqrt(13/6)*(S1);
and for long
Code:
S2 = [1,1,-1,-1,1,1,-1,1,-1,1,1,...
    1,1,1,1,-1,-1,1,1,-1,1,-1,1,1, 1, 1, 0, 1,...
    -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1,...
    -1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1];

But, for My case that is related to "802.11n with (40Mhz - FFT size 128 point - 64QAM)", I do not know, How to I can generate this values?
Are these values the same for the 802.11 family or not?
If anyone knows how to generate these values (short and long), please guide me.
 

But, for My case that is related to "802.11n with (40Mhz - FFT size 128 point - 64QAM)", I do not know, How to I can generate this values?

The 64QAM part is irrelevant. That is the data constellation, which is not related to the preamble.

The short answer to your question is that the training sequences for 40MHz are basically the same as two 20MHz bands stacked side by side. This is required for legacy reasons: an 802.11g device (operating on a 20MHz channel) needs to be able to detect either half of a 40MHz 802.11n (Mixed Format) transmission in order to determine how the shared channel is being used.

There may be a phase rotation between the upper and lower halves (I can't remember off the top of my head - you'll have to look that up), but basically an 802.11g burst detector would successfully detect each half of the 40MHz 802.11n transmission.
 
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