block.c

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

/***************************************************************************
 *    block.c  - Define a block with an input or output-size
 *                           -------------------
 *   begin                :  date
 *   authors              :  name
 *   emails               :  email address
 ***************************************************************************/

/***************************************************************************
 *                                Changes
 *                                -------
 * date - name - description
 * 03/01/29 - ineiti - start
 * 03/04/01 - chiurtu - added gaussian noise
 * 04/03/05 - ineiti - adjusted documentation
 *
 **************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/


/**
 * After the modules work with a very simple chain, it is nice to have a
 * next step before using the channel-simulator. The 'block' goes between
 * 'rrc' and 'matched_filter' and simulates a perfect channel with the
 * appropriate attenuation. A future todo could be to add some noise.
 *  As most of the normal chains don't set the IO-size, you can do so
 * using the 'size'-config
 */

#include <stdlib.h>
#include "spc.h"


#define DBG_LVL 0
#define MALLOC_BORDER 256
#define RX_TX_DELAY 0

typedef struct {
  // sets the size in samples.
  int size; // 2560
  // sets the variance of the gaussian noise.
  double sigma; // 100
  // sets the amplitude of the white noise.
  int noise_amplitude; // 0
}
config_t;

typedef struct {}
stats_t;

typedef struct {
  int size;
  SAMPLE_S12 *in, *out;
  double sigma;
  int noise_amplitude;

  unsigned short simrand[3];
}
private_t;


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

int spc_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

  // Tell the subsystem we don't accept resizes, but only emit them
  context->status |= SUBS_STATUS_RESIZE_NONE;

  private->size = 0;
  // We set the standard UMTS-size for the slot
  config->size = 2560 * 4;
  config->noise_amplitude = 0;
  config->sigma = 100;
  port_in(0).flags |= SWR_PORT_OWN_MALLOC;
  port_in(0).data = 0;
  port_out(0).flags |= SWR_PORT_OWN_MALLOC;
  port_out(0).data = 0;
  private->in = private->out = 0;
  srand( (int)get_time_usec()%100000000 );

  // initialize the random generator
  private->simrand[0]=(unsigned short)((get_time_usec()>>00)&0xffff);
  private->simrand[1]=(unsigned short)((get_time_usec()>>16)&0xffff);
  private->simrand[2]=(unsigned short)((get_time_usec()>>00)&0xffff);


  // 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
}


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

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

  if ( config->size != private->size ) {
    PR_DBG( 2, "Re-setting sizes: %i, %i\n", config->size, private->size );
    private->size = config->size;
    size_in(0) = config->size;
    size_out(0) = config->size;
    swr_free( private->in );
    swr_free( private->out );

    private->in = swr_malloc( ( private->size + 2 * MALLOC_BORDER ) *
                              sizeof( SAMPLE_S12 ) );
    port_in(0).data = private->in + MALLOC_BORDER;

    private->out = swr_malloc( ( private->size + 2 * MALLOC_BORDER ) *
                               sizeof( SAMPLE_S12 ) );
    port_out(0).data = private->out + MALLOC_BORDER;
  }
  private->noise_amplitude = config->noise_amplitude;
  private->sigma = config->sigma;

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


/*
 * This is the function that implements the `main method' of the class
 * Every class has got just ONE method/working-mode.
 */
int spc_pdata( swr_sdb_t *context ) {
  // Definition of variables - don't touch
  stats_t *stats;
  SAMPLE_S12 *in, *out;
  int i,j;
  double u, v;
  double alpha, w;


  // Just to transmit the PORT_DATA flag from the input
  // to the output
  in = buffer_in(0);
  out = buffer_out(0);
  if ( private->size ) {
    in = private->in;
    out = private->out;
    for ( i=0; i<private->size + 2 * MALLOC_BORDER - RX_TX_DELAY; i++ ) {
      out[ i ] = in[ i + RX_TX_DELAY ] / 16 / 1;
      out[ i ] += ((2.*private->noise_amplitude)*rand()/(RAND_MAX+1.0)) - private->noise_amplitude;
      //     j= 0;
      do {
        u = 2*erand48(private->simrand)-1;
        v = 2*erand48(private->simrand)-1;

        w = u*u + v*v;
        j++;
      } while (w>=1);

      //      if ( j > 1 ){
      //	PR_DBG( 4, "while-loop done: %i\n", j );
      //}
      alpha = sqrt(-2*log(w)/w);
      out[i] += private->sigma*alpha*u;
      out[i] = max( out[i], (short int)-2048 );
      out[i] = min( out[i], (short int)2047 );
    }
  }

  swr_sdb_get_stats_struct( context->id, (void**)&stats );
  // Put your code here
  // ADD HERE
  swr_sdb_free_stats_struct( context->id, (void**)&stats );
  return(0);
}

/*
 * This is the `destructor'.
 */
int spc_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 cdb_id;
int spc_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,POINTER}( "name" );
   * UM_STATS_{INT,DOUBLE,STRING128,POINTER,BLOCK}( "name" );
   */
  UM_CONFIG_INT( "size" );
  UM_CONFIG_DOUBLE( "sigma" );
  UM_CONFIG_INT( "noise_amplitude" );
  /**
   * 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_SAMPLE_S12, 0 );
  UM_OUTPUT( SIG_SAMPLE_S12, 0 );

  // Initialise the callback-functions. Delete the ones you don't use
  desc->fn_init              = spc_init;
  desc->fn_reconfigure       = spc_reconfig;
  desc->fn_process_data      = spc_pdata;
  desc->fn_finalize          = spc_finalize;

  // And register the module in the SPM. Change the name!
  cdb_id = swr_cdb_register_spc( &desc, "block" );
  if ( cdb_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 spc_module_exit( void ) {
  PR_DBG( 4, "Freeing id: %i\n", cdb_id );
  if ( swr_cdb_unregister_spc( cdb_id ) < 0 ) {
    PR_DBG( 0, "Still in use somewhere\n" );
  }
}


module_init( spc_module_init );
module_exit( spc_module_exit );