test_convolution.c

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

/***************************************************************************
              test_convolution.c  -  Module for testing convolutional coding
                            -------------------
    begin                :  03/12/10
    authors              :  Roman Hofer
    emails               :  [e-mail]
 ***************************************************************************/

/***************************************************************************
                                 Changes
                                 -------
 date - name - description
 04/03/03 - ineiti - added a 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.                                   *
 *                                                                         *
 ***************************************************************************/


char desc[] =
"Description:\n"
"This is a test for the convolutional Code.\n"
"It uses a random source, an encoder, a very simple channel simulation\n"
"which introduces biterrors, a decoder and a sink.\n"
"You should see errors appearing at a BER of around 0.05\n\n";

#include "spc.h"
#include "std.h"

#define DBG_LVL 4


struct chain_t *test_chain;

// also nice (n,k,m)=(7,5,8) and REG_STATUS polys[] = {0x3f,0xad,0x06,0xf1,0x7a,0xa5,0x49};
// also nice (n,k,m)=(2,1,4) REG_STATUS polys[] = {0x0f,0x0d};
// also nice (n,k,m)=(4,2,4) REG_STATUS polys[] = {0x0f,0x0d,0x08,0x03};

int cfg_n=2;
int cfg_k=1;
int cfg_m=8;
int cfg_trunclength=100;
int cfg_truncblock=50;
unsigned int polys[] = {0x37,0x73};
double ber;


void *start_it( void *arg ) {
  int data_bits = 512*8;

  swr_sdb_id rnd, conv_send, biterror, conv_rcv, test_send, test_rcv;

  test_chain = swr_chain_create(NEW_SPC_VAR( "random", rnd ),
                                NEW_SPC_VAR( "test_data_send", test_send ),
                                NEW_SPC_VAR( "convolution_send", conv_send ),
                                NEW_SPC_VAR( "biterror", biterror ),
                                NEW_SPC_VAR( "convolution_rcv", conv_rcv ),
                                NEW_SPC_VAR( "test_data_rcv", test_rcv ),
                                CHAIN_END );

  swr_conn_add( test_send, 1,
                test_rcv, 1 );
  // Clear the error counter each time
  swr_sdb_set_config_int( test_rcv, "mode", 1 );
  //Configure size of the test_data_rcv
  swr_sdb_set_config_int( test_rcv, "size", data_bits / 8 );


  PR_DBG( 3, "Starting\n" );
  //Configure source
  swr_sdb_set_config_int( rnd, "seed", 0x1234 );

  //Configure encoder
  swr_sdb_set_config_int( conv_send, "cfg_n", cfg_n );
  swr_sdb_set_config_int( conv_send, "cfg_k", cfg_k );
  swr_sdb_set_config_int( conv_send, "cfg_m", cfg_m );
  swr_sdb_set_config_pointer( conv_send, "cfg_polys", polys );

  //Configure decoder
  swr_sdb_set_config_int( conv_rcv, "cfg_n", cfg_n );
  swr_sdb_set_config_int( conv_rcv, "cfg_k", cfg_k );
  swr_sdb_set_config_int( conv_rcv, "cfg_m", cfg_m );
  swr_sdb_set_config_int( conv_rcv, "cfg_trunclength", cfg_trunclength );
  swr_sdb_set_config_int( conv_rcv, "cfg_truncblock", cfg_truncblock );
  swr_sdb_set_config_pointer( conv_rcv, "cfg_polys", polys );	//polynomes, must

  for ( ber = 0; ber <= 0.1; ber += 0.01 ) {
    //Configure channel
    swr_sdb_set_config_double( biterror, "ber", ber );	//errorbrob 2%
    //Now activate the conv_send module
    call_module( rnd );

    PR( "BER: %g, Errors: %g\n", ber,
        ((double)swr_sdb_get_stats_int( test_rcv, "error" )) / data_bits );
  }

  return 0;
}

swr_spc_id_t spm_id;

struct thread start;
/**
 * This function is called upon "insmod" and is used to register the
 * different parts of the module to the SPM.
 */
int um_module_init(void) {

  PR_CL( desc );

  test_chain = NULL;
  if ( swr_thread_init( &start, start_it, NULL ) < 0 )
    goto first_no_stack;
  return 0;

first_no_stack:
  PR_DBG( 0, "Couldn't allocate stack\n" );
  return -1;
}

void um_module_exit( void ) {

  swr_thread_free( &start, NULL );
  swr_chain_destroy( test_chain );

}


module_init( um_module_init );
module_exit( um_module_exit );