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   1 /* -*- c++ -*- */
   2 /*
   3  * Copyright 2007 Free Software Foundation, Inc.
   4  *
   5  * This file is part of GNU Radio
   6  *
   7  * GNU Radio is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3, or (at your option)
  10  * any later version.
  11  *
  12  * GNU Radio is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with GNU Radio; see the file COPYING.  If not, write to
  19  * the Free Software Foundation, Inc., 51 Franklin Street,
  20  * Boston, MA 02110-1301, USA.
  21  */
  22
  23 #ifndef INCLUDED_GR_OFDM_FRAME_SINK_H
  24 #define INCLUDED_GR_OFDM_FRAME_SINK_H
  25
  26 #include <gr_sync_block.h>
  27 #include <gr_msg_queue.h>
  28
  29 class gr_ofdm_frame_sink;
  30 typedef boost::shared_ptr<gr_ofdm_frame_sink> gr_ofdm_frame_sink_sptr;
  31
  32 gr_ofdm_frame_sink_sptr
  33 gr_make_ofdm_frame_sink (const std::vector<gr_complex> &sym_position,
  34                          const std::vector<unsigned char> &sym_value_out,
  35                          gr_msg_queue_sptr target_queue, unsigned int occupied_tones,
  36                          float phase_gain=0.25, float freq_gain=0.25*0.25/4.0);
  37
  38 /*!
  39  * \brief Takes an OFDM symbol in, demaps it into bits of 0's and 1's, packs
  40  * them into packets, and sends to to a message queue sink.
  41  * \ingroup sink_blk
  42  * \ingroup ofdm_blk
  43  *
  44  * NOTE: The mod input parameter simply chooses a pre-defined demapper/slicer. Eventually,
  45  * we want to be able to pass in a reference to an object to do the demapping and slicing
  46  * for a given modulation type.
  47  */
  48 class gr_ofdm_frame_sink : public gr_sync_block
  49 {
  50   friend gr_ofdm_frame_sink_sptr
  51   gr_make_ofdm_frame_sink (const std::vector<gr_complex> &sym_position,
  52                            const std::vector<unsigned char> &sym_value_out,
  53                            gr_msg_queue_sptr target_queue, unsigned int occupied_tones,
  54                            float phase_gain, float freq_gain);
  55
  56  private:
  57   enum state_t {STATE_SYNC_SEARCH, STATE_HAVE_SYNC, STATE_HAVE_HEADER};
  58
  59   static const int MAX_PKT_LEN    = 4096;
  60   static const int HEADERBYTELEN   = 4;
  61
  62   gr_msg_queue_sptr  d_target_queue;            // where to send the packet when received
  63   state_t            d_state;
  64   unsigned int       d_header;                  // header bits
  65   int                d_headerbytelen_cnt;       // how many so far
  66
  67   unsigned char      *d_bytes_out;              // hold the current bytes produced by the demapper
  68
  69   unsigned int       d_occupied_carriers;
  70   unsigned int       d_byte_offset;
  71   unsigned int       d_partial_byte;
  72
  73   unsigned char      d_packet[MAX_PKT_LEN];     // assembled payload
  74   int                d_packetlen;               // length of packet
  75   int                d_packet_whitener_offset;  // offset into whitener string to use
  76   int                d_packetlen_cnt;           // how many so far
  77
  78   gr_complex * d_derotated_output;  // Pointer to output stream to send deroated symbols out
  79
  80   std::vector<gr_complex>    d_sym_position;
  81   std::vector<unsigned char> d_sym_value_out;
  82   std::vector<gr_complex>    d_dfe;
  83   unsigned int d_nbits;
  84
  85   unsigned char d_resid;
  86   unsigned int d_nresid;
  87   float d_phase;
  88   float d_freq;
  89   float d_phase_gain;
  90   float d_freq_gain;
  91   float d_eq_gain;
  92
  93   std::vector<int> d_subcarrier_map;
  94
  95  protected:
  96   gr_ofdm_frame_sink(const std::vector<gr_complex> &sym_position,
  97                      const std::vector<unsigned char> &sym_value_out,
  98                      gr_msg_queue_sptr target_queue, unsigned int occupied_tones,
  99                      float phase_gain, float freq_gain);
 100
 101   void enter_search();
 102   void enter_have_sync();
 103   void enter_have_header();
 104
 105   bool header_ok()
 106   {
 107     // confirm that two copies of header info are identical
 108     return ((d_header >> 16) ^ (d_header & 0xffff)) == 0;
 109   }
 110
 111   unsigned char slicer(const gr_complex x);
 112   unsigned int demapper(const gr_complex *in,
 113                         unsigned char *out);
 114
 115   bool set_sym_value_out(const std::vector<gr_complex> &sym_position,
 116                          const std::vector<unsigned char> &sym_value_out);
 117
 118  public:
 119   ~gr_ofdm_frame_sink();
 120
 121   int work(int noutput_items,
 122            gr_vector_const_void_star &input_items,
 123            gr_vector_void_star &output_items);
 124 };
 125
 126 #endif /* INCLUDED_GR_OFDM_FRAME_SINK_H */