GNU Radio 3.5.3.2 C++ API
digital_ofdm_frame_sink.h
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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2007,2011 Free Software Foundation, Inc.
00004  * 
00005  * This file is part of GNU Radio
00006  * 
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  * 
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  * 
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 #ifndef INCLUDED_DIGITAL_OFDM_FRAME_SINK_H
00024 #define INCLUDED_DIGITAL_OFDM_FRAME_SINK_H
00025 
00026 #include <digital_api.h>
00027 #include <gr_sync_block.h>
00028 #include <gr_msg_queue.h>
00029 
00030 class digital_ofdm_frame_sink;
00031 typedef boost::shared_ptr<digital_ofdm_frame_sink> digital_ofdm_frame_sink_sptr;
00032 
00033 DIGITAL_API digital_ofdm_frame_sink_sptr 
00034 digital_make_ofdm_frame_sink (const std::vector<gr_complex> &sym_position, 
00035                               const std::vector<unsigned char> &sym_value_out,
00036                               gr_msg_queue_sptr target_queue, unsigned int occupied_tones,
00037                               float phase_gain=0.25, float freq_gain=0.25*0.25/4.0);
00038 
00039 /*!
00040  * \brief Takes an OFDM symbol in, demaps it into bits of 0's and 1's, packs
00041  * them into packets, and sends to to a message queue sink.
00042  * \ingroup sink_blk
00043  * \ingroup ofdm_blk
00044  *
00045  * NOTE: The mod input parameter simply chooses a pre-defined demapper/slicer. Eventually,
00046  * we want to be able to pass in a reference to an object to do the demapping and slicing
00047  * for a given modulation type.
00048  */
00049 class DIGITAL_API digital_ofdm_frame_sink : public gr_sync_block
00050 {
00051   friend DIGITAL_API digital_ofdm_frame_sink_sptr 
00052   digital_make_ofdm_frame_sink (const std::vector<gr_complex> &sym_position, 
00053                                 const std::vector<unsigned char> &sym_value_out,
00054                                 gr_msg_queue_sptr target_queue, unsigned int occupied_tones,
00055                                 float phase_gain, float freq_gain);
00056 
00057  private:
00058   enum state_t {STATE_SYNC_SEARCH, STATE_HAVE_SYNC, STATE_HAVE_HEADER};
00059 
00060   static const int MAX_PKT_LEN    = 4096;
00061   static const int HEADERBYTELEN   = 4;
00062 
00063   gr_msg_queue_sptr  d_target_queue;            // where to send the packet when received
00064   state_t            d_state;
00065   unsigned int       d_header;                  // header bits
00066   int                d_headerbytelen_cnt;       // how many so far
00067 
00068   unsigned char      *d_bytes_out;              // hold the current bytes produced by the demapper    
00069 
00070   unsigned int       d_occupied_carriers;
00071   unsigned int       d_byte_offset;
00072   unsigned int       d_partial_byte;
00073 
00074   unsigned char      d_packet[MAX_PKT_LEN];     // assembled payload
00075   int                d_packetlen;               // length of packet
00076   int                d_packet_whitener_offset;  // offset into whitener string to use
00077   int                d_packetlen_cnt;           // how many so far
00078 
00079   gr_complex * d_derotated_output;  // Pointer to output stream to send deroated symbols out
00080 
00081   std::vector<gr_complex>    d_sym_position;
00082   std::vector<unsigned char> d_sym_value_out;
00083   std::vector<gr_complex>    d_dfe;
00084   unsigned int d_nbits;
00085 
00086   unsigned char d_resid;
00087   unsigned int d_nresid;
00088   float d_phase;
00089   float d_freq;
00090   float d_phase_gain;
00091   float d_freq_gain;
00092   float d_eq_gain;
00093 
00094   std::vector<int> d_subcarrier_map;
00095 
00096  protected:
00097   digital_ofdm_frame_sink(const std::vector<gr_complex> &sym_position, 
00098                           const std::vector<unsigned char> &sym_value_out,
00099                           gr_msg_queue_sptr target_queue, unsigned int occupied_tones,
00100                           float phase_gain, float freq_gain);
00101 
00102   void enter_search();
00103   void enter_have_sync();
00104   void enter_have_header();
00105   
00106   bool header_ok()
00107   {
00108     // confirm that two copies of header info are identical
00109     return ((d_header >> 16) ^ (d_header & 0xffff)) == 0;
00110   }
00111   
00112   unsigned char slicer(const gr_complex x);
00113   unsigned int demapper(const gr_complex *in,
00114                         unsigned char *out);
00115 
00116   bool set_sym_value_out(const std::vector<gr_complex> &sym_position, 
00117                          const std::vector<unsigned char> &sym_value_out);
00118 
00119  public:
00120   ~digital_ofdm_frame_sink();
00121 
00122   int work(int noutput_items,
00123            gr_vector_const_void_star &input_items,
00124            gr_vector_void_star &output_items);
00125 };
00126 
00127 #endif /* INCLUDED_GR_OFDM_FRAME_SINK_H */