On Mon, May 03, 2010 at 09:25:56PM +0000, jack william wrote: > Hi, > Could someone please answer following questions of mine : > 1) In > pkt = ofdm_packet_utils.make_packet(payload, 1, 1, self._pad_for_usrp, > whitening=True) > > what is whitening?
It scrambles up your bits (makes them white in a stochastic sense). > > 2) In gr.fft_vcc(fft_size,forward, window, shift=false) > What is window vector? A tapering window applied before the actual FFT (like a Hamming window) > 3) in ofdm_mod there is a portion of code having comments: > Use freq domain to get doubled-up known symbol for correlation in time domain This is part of OFDM timing synchronisation. You probably want to read up on that topic if your interested (e.g., the paper on OFDM synch by Schmidl & Cox). Cheers MB -- Karlsruhe Institute of Technology (KIT) Communications Engineering Lab (CEL) Dipl.-Ing. Martin Braun Research Associate Kaiserstraße 12 Building 05.01 76131 Karlsruhe Phone: +49 721 608-3790 Fax: +49 721 608-6071 www.cel.kit.edu KIT -- University of the State of Baden-Württemberg and National Laboratory of the Helmholtz Association
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