diff options
| author | Johnathan Corgan <johnathan@corganlabs.com> | 2013-03-15 09:57:31 -0700 |
|---|---|---|
| committer | Johnathan Corgan <johnathan@corganlabs.com> | 2013-03-15 09:57:31 -0700 |
| commit | e965a5bb209ad46a509ccd21f393667fd69d95f9 (patch) | |
| tree | 40d683ef8f80980f12eac6cfe7f3423c49b45f87 /gr-digital/include/digital_ofdm_sync_sc_cfb.h | |
| parent | 2bf9c4cb4b0b426690f353fc1662a13e70c0d5e0 (diff) | |
| parent | 27990ca9e236931e39a830e48f0a1efe13ec085f (diff) | |
Merge branch 'ofdm-master' into ofdm-next
Added fixups for next branch changes
Conflicts:
CMakeLists.txt
gnuradio-core/src/lib/io/gr_message_sink.cc
gnuradio-core/src/lib/io/gr_message_sink.h
gnuradio-core/src/lib/io/gr_message_sink.i
gnuradio-core/src/lib/io/gr_message_source.cc
gnuradio-core/src/lib/io/gr_message_source.h
gnuradio-core/src/lib/io/gr_message_source.i
gr-blocks/CMakeLists.txt
gr-digital/CMakeLists.txt
gr-digital/grc/digital_block_tree.xml
gr-digital/include/digital/CMakeLists.txt
gr-digital/include/digital_ofdm_cyclic_prefixer.h
gr-digital/lib/CMakeLists.txt
gr-digital/lib/digital_ofdm_cyclic_prefixer.cc
gr-digital/lib/ofdm_cyclic_prefixer_impl.h
gr-digital/python/CMakeLists.txt
gr-digital/swig/CMakeLists.txt
gr-digital/swig/digital_swig.i
Diffstat (limited to 'gr-digital/include/digital_ofdm_sync_sc_cfb.h')
| -rw-r--r-- | gr-digital/include/digital_ofdm_sync_sc_cfb.h | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/gr-digital/include/digital_ofdm_sync_sc_cfb.h b/gr-digital/include/digital_ofdm_sync_sc_cfb.h new file mode 100644 index 0000000000..cc728814ed --- /dev/null +++ b/gr-digital/include/digital_ofdm_sync_sc_cfb.h @@ -0,0 +1,79 @@ +/* -*- c++ -*- */ +/* Copyright 2012 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3, or (at your option) + * any later version. + * + * GNU Radio is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, + * Boston, MA 02110-1301, USA. + */ + +#ifndef INCLUDED_DIGITAL_OFDM_SYNC_SC_CFB_H +#define INCLUDED_DIGITAL_OFDM_SYNC_SC_CFB_H + +#include <digital/api.h> +#include <gr_hier_block2.h> + +class digital_ofdm_sync_sc_cfb; +typedef boost::shared_ptr<digital_ofdm_sync_sc_cfb> digital_ofdm_sync_sc_cfb_sptr; + +/*! \param fft_len FFT length + * \param cp_len Length of the guard interval (cyclic prefix) in samples + */ +DIGITAL_API digital_ofdm_sync_sc_cfb_sptr +digital_make_ofdm_sync_sc_cfb (int fft_len, int cp_len); + +/*! + * \brief Schmidl & Cox synchronisation for OFDM + * \ingroup ofdm_blk + * \ingroup sync_blk + * + * Input: complex samples. + * Output 0: Fine frequency offset, scaled by the OFDM symbol duration. + * This is \f$\hat{\varphi}\f$ in [1]. The normalized frequency + * offset is then 2.0*output0/fft_len. + * Output 1: Beginning of the first OFDM symbol after the first (doubled) OFDM + * symbol. The beginning is marked with a 1 (it's 0 everywhere else). + * + * The evaluation of the coarse frequency offset is *not* done in this block. + * Also, the initial equalizer taps are not calculated here. + * + * Note that we use a different normalization factor in the timing metric than + * the authors do in their original work[1]. If the timing metric (8) is + * \f[ + * M(d) = \frac{|P(d)|^2}{(R(d))^2}, + * \f] + * we calculate the normalization as + * \f[ + * R(d) = \frac{1}{2} \sum_{k=0}^{N-1} |r_{k+d}|^2, + * \f] + * i.e., we estimate the energy from *both* half-symbols. This avoids spurious detects + * at the end of a burst, when the energy level suddenly drops. + * + * [1] Schmidl, T.M. and Cox, D.C., "Robust frequency and timing synchronization for OFDM", + * Communications, IEEE Transactions on, 1997. + */ +class DIGITAL_API digital_ofdm_sync_sc_cfb : public gr_hier_block2 +{ + private: + friend DIGITAL_API digital_ofdm_sync_sc_cfb_sptr digital_make_ofdm_sync_sc_cfb (int fft_len, int cp_len); + digital_ofdm_sync_sc_cfb(int fft_len, int cp_len); + + public: + ~digital_ofdm_sync_sc_cfb(); + +}; + +#endif /* INCLUDED_DIGITAL_OFDM_SYNC_SC_CFB_H */ + |