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Re: [Discuss-gnuradio] How many preambles uesd in ofdm example for frame
From: |
Martin Braun (CEL) |
Subject: |
Re: [Discuss-gnuradio] How many preambles uesd in ofdm example for frame synchronization, 10 short preambles ? |
Date: |
Mon, 8 Apr 2013 09:30:11 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Sun, Apr 07, 2013 at 11:49:14AM +0800, Yingjie Chen wrote:
> Thanks for your reply. I still have one question. I try to plot the peak
> detection data to observe the the shape of the peak, which seems like
> a plateau(square wave).I have done a simulation before in matlab. If only
> one preamble exist, when the 1st half of the preamble correlate with 2nd
> half, the shape of peak should be much sharper(like a triangle), because
> the repeated pattern is not enough.
> My question is :
> If gunradio only use one preamble with 2 repeated pattern, the shape of the
> peak should look like a triangle rather than a plateau, is that right?
No, the plateau is correct. Since your correlation window is 2x half of
1 symbol, the cyclic prefix will increase your peak (in AWGN channels to
the length of the cyclic prefix).
MB
--
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)
Dipl.-Ing. Martin Braun
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KIT -- University of the State of Baden-Württemberg and
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