mapper_send.c

This a framework to test new ideas in transmission technology. Actual development is a LDPC-coder in

/***************************************************************************
 *    mapper.c  - Modulate bits to symbols
 *                           -------------------
 *   begin                :  02/10/30
 *   authors              :  Linus Gasser
 *   emails               :  [e-mail]
 ***************************************************************************/

/***************************************************************************
 *                                Changes
 *                                -------
 * date - name - description
 * 02/10/30 - ineiti - begin
 * 03/02/12 - ineiti - added symbol-look-up tables for PSK and QAM
 * 03/05/12 - ineiti - Cleanup the checks on the config and adjust mapper.h
 *                     so that no symbol has an energy of more than 256
 * 04/03/06 - ineiti - adjusted description
 *
 **************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program 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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/


/**
 * A simple mapper-class for demodulator and mapper. 
 * It supports different PSK and QAM symbols
 */

#include "spc.h"
#include "mapper.h"

#define DBG_LVL 0


typedef struct {
  // The amplitude of the symbols
  int amplitude; // 32767
  // The bits per symbol
  int bits_per_symbol; // 2
  // Which table to take: 0-PSK   1-QAM
  int symbol_type; // 0
}
config_t;

typedef struct {}
stats_t;

typedef struct {
  int bits_per_symbol;
  SYMBOL_COMPLEX table[16];
}
private_t;


/*
 * The initialisation function, or constructor, 
 * is called the first time this module is instantiated.
 */

int send_init( swr_sdb_t *context ) {
  // Begin system-definitions {
  config_t *config;
  stats_t *stats;
  MOD_INC_USE_COUNT;

  if ( sizeof( private_t ) > 0 )
    context->private_data = swr_malloc( sizeof( private_t ) );
  swr_sdb_get_config_struct( context->id, (void**)&config );
  swr_sdb_get_stats_struct( context->id, (void**)&stats );
  // } End of system-definitions

  // Usually we have symbols in the 'coins', that is the total energy =
  // sqrt( re^2 + im^2 ) = sqrt( amp^2/2 + amp^2/2 ) = amp
  config->amplitude = 32767;
  config->bits_per_symbol = 2;
  config->symbol_type = 0;

  // Begin system-definitions
  swr_sdb_free_stats_struct( context->id, (void**)&stats );
  swr_sdb_free_config_struct( context->id, (void**)&config );
  return 0;
  // End system-definitions
}


/*
 * To configure the inputs
 * this is called when the output-sizes change.
 */
int send_configure_inputs( swr_sdb_t *context ) {
  // Definition of variables - don't touch
  config_t *config;
  swr_sdb_get_config_struct( context->id, (void**)&config );

  size_in(0) = size_out(0) * private->bits_per_symbol / 8;
  PR_DBG( 3, "size_in: %i\n", size_in(0) );

  // Definition - don't touch
  swr_sdb_free_config_struct( context->id, (void**)&config );
  return 0;
}


/*
 * To configure the outputs
 * this is called when the input-sizes change
 */
int send_configure_outputs( swr_sdb_t *context ) {
  // Definition of variables - don't touch
  config_t *config;
  int size;
  swr_sdb_get_config_struct( context->id, (void**)&config );

  // Only resize if we have really something more. If not it may
  // be some aliasing of the port-sizes.
  size = ceil( size_in(0) * 8. / private->bits_per_symbol );
  if ( ( size_out(0) - size ) * private->bits_per_symbol / 8 ) {
    size_out(0) = size;
  }
  PR_DBG( 3, "size_out: %i\n", size_out(0) );

  // Definition - don't touch
  swr_sdb_free_config_struct( context->id, (void**)&config );
  return 0;
}


/*
 * Every time modules from the outside change the value of a configuration parameter,
 * this function is called.
 */

int send_reconfig( swr_sdb_t *context ) {
  // Definition of variables - don't touch
  int i, j;
  config_t *config;
  swr_sdb_get_config_struct( context->id, (void**)&config );

  if ( ( config->bits_per_symbol <= MAX_BITS ) &&
       ( config->symbol_type <= 1 ) &&
       ( config->bits_per_symbol > 0 ) ) {
    private->bits_per_symbol = config->bits_per_symbol;
    size_in(0) = floor( size_out(0) * private->bits_per_symbol / 8. );
    j = private->bits_per_symbol;
    for ( i=0; i<(1<<j); i++ ) {
      switch( config->symbol_type ) {
      case 0:
        private->table[i].real = (short)((int)config->amplitude *
                                         Symbols_PSK[j-1][i].real / 256 );
        private->table[i].imag = (short)((int)config->amplitude *
                                         Symbols_PSK[j-1][i].imag / 256 );
        break;
      case 1:
        private->table[i].real = (short)((int)config->amplitude *
                                         Symbols_QAM[j-1][i].real / 256 );
        private->table[i].imag = (short)((int)config->amplitude *
                                         Symbols_QAM[j-1][i].imag / 256 );
        break;
      }
      PR_DBG( 4, "Symbol %i: (%i,%i)\n", i,
              private->table[i].real, private->table[i].imag );
    }
  }


  // Definition - don't touch
  swr_sdb_free_config_struct( context->id, (void**)&config );
  return 0;
}


/*
 * This is function that impements the `main method' of the class
 * Every calss has got just ONE method/working-mode.
 */
int send_pdata( swr_sdb_t *context ) {
  // Definition of variables - don't touch
  config_t *config;
  stats_t *stats;
  U8 *in;
  SYMBOL_COMPLEX *out;
  int i, index = 0, j, k;

  swr_sdb_get_config_struct( context->id, (void**)&config );
  swr_sdb_free_config_struct( context->id, (void**)&config );

  in = buffer_in( 0 );
  out = buffer_out( 0 );

  PR_DBG( 4, "Got buffer-in at %p for %i len\n", in, size_out(0) );
  j = private->bits_per_symbol;
  k = 0;
  for ( i=0; i < size_out(0); i++ ) {
    if ( k < private->bits_per_symbol ) {
      index += *in << k;
      in++;
      k += 8;
    }
    out[i] = private->table[ index & ( ( 1 << j ) - 1 ) ];
    
    if( i<10) {
      PR_DBG( 4, "sent: (%5i, %5i)\n", 
	      private->table[ index & ( ( 1 << j ) - 1 ) ].real, 
	      private->table[ index & ( ( 1 << j ) - 1 ) ].imag );
    }
    index = index >> j;
    k -= private->bits_per_symbol;
  }

  swr_sdb_get_stats_struct( context->id, (void**)&stats );
  swr_sdb_free_stats_struct( context->id, (void**)&stats );

  return(0);
}

/**
 *  * User messages
 *   */
int send_custom_msg( swr_sdb_t *context, swr_usr_msg_t *data, swr_msgq ret ) {

  send_pdata( context );
  return 0;
}


/*
 * This is the `destructor'.
 */
int send_finalize( swr_sdb_t *context ) {
  if ( sizeof( private_t ) > 0 )
    swr_free( private );
  MOD_DEC_USE_COUNT;
  return 0;
}


/*
 * This function is called upon "insmod" and is used to register the
 * different parts of the module to the SPM.
 */
swr_spc_id_t send_id;
int send_module_init(void) {
  swr_spc_desc_t *desc;
  /**
   * Get a description-part from SPM
   * Give the following parameters:
   * Input-ports, output-ports, config-params, stat-params
   */
  desc = swr_spc_get_new_desc( 1, 1, 3, 0 );
  if ( !desc ) {
    PR_DBG( 0, "Can't initialise the module. This is BAD!\n" );
    return -1;
  }

  /**
   * Define the different parts of config and stats. You have to define
   * them in the same order as they appear in the structures. The names
   * can be freely chosen.
   *
   * UM_CONFIG_{INT,DOUBLE,STRING128}( "name" );
   * UM_STATS_{INT,DOUBLE,STRING128}( "name" );
   */
  UM_CONFIG_INT( "amplitude" );
  UM_CONFIG_INT( "bits_per_symbol" );
  UM_CONFIG_INT( "symbol_type" );
  /**
   * The in- and outputs have also to be defined in the right order. First
   * port first. The additional flag is not used yet, but it will...
   *
   * UM_INPUT( SIG_{U8,SYMBOL_{S16,COMPLEX,MMX},SAMPLE_S12,S32}, 0 );
   * UM_OUTPUT( SIG_{U8,SYMBOL_{S16,COMPLEX,MMX},SAMPLE_S12,S32}, 0 );
   */
  UM_INPUT( SIG_U8, 0 );
  UM_OUTPUT( SIG_SYMBOL_COMPLEX, 0 );

  // Initialise the callback-functions. Delete the ones you don't use
  desc->fn_init              = send_init;
  desc->fn_reconfigure       = send_reconfig;
  desc->fn_process_data      = send_pdata;
  desc->fn_custom_msg	     = send_custom_msg;
  desc->fn_configure_inputs  = send_configure_inputs;
  desc->fn_configure_outputs = send_configure_outputs;
  desc->fn_finalize          = send_finalize;

  // And register the module in the SPM. Change the name!
  send_id = swr_cdb_register_spc( &desc, "mapper" );
  if ( send_id == SWR_SPM_INVALID_ID ) {
    swr_spc_free_desc( desc );
    PR_DBG( 0, "Couldn't register the module!\n" );
    return 1;
  }
  PR_DBG( 4, "Ready\n" );
  return 0;
}


/*
 * This is called upon rmmod
 */
void send_module_exit( void ) {
  PR_DBG( 4, "Freeing id: %i\n", send_id );
  if ( swr_cdb_unregister_spc( send_id ) < 0 ) {
    PR_DBG( 0, "Still in use somewhere\n" );
  }
}