test_ldpc.c

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

/***************************************************************************
              test_ldpc.c - a first LDPC test
                            -------------------
    begin                :  2003
    authors              :  Nicolae Chiurtu
    emails               :  [e-mail]
 ***************************************************************************/

/***************************************************************************
                                 Changes
                                 -------
 date - name - description
 04/03/03 - ineiti - added a short 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"
"Makes up a small chain containing an LDPC-encoder and decoder, complete\n"
"with channel estimation and all. The output is supposed to give the\n"
"time spent for different LDPC-codes, as well as the well-known test-phrase.\n"
"A code 0.25, 0.5 and 0.75 respectiveley are used.\n\n";

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

#define DBG_LVL 4
#define BYPASS 0


struct chain_t *test_chain;

void *start_it( void *arg ) {
  int i;
  swr_sdb_id rand, encode, mod, decode, sink, block, mafi_id;
#if BYPASS

  swr_sdb_id demod;
#endif

  test_chain = swr_chain_create(
                 NEW_SPC_VAR( "source", rand ),
#if !BYPASS
                 NEW_SPC_VAR( "ldpc_encode", encode),
#endif
                 NEW_SPC_VAR( "mapper", mod ),
                 NEW_SPC( "midamble" ),
                 NEW_SPC( "rrc" ),
                 NEW_SPC_VAR( "block", block ),
                 NEW_SPC_VAR( "matched_filter", mafi_id ),
#if BYPASS
                 NEW_SPC_VAR( "slicer", demod ),
#else
                 NEW_SPC_VAR( "ldpc_decode", decode),
#endif
                 NEW_SPC_VAR( "sink", sink ),
                 CHAIN_END );


  // Initialise input-size of the sink. Necessary because we don't
  // have a STFA
  swr_sdb_set_config_int( sink, "flag", 1 );
  swr_sdb_set_config_int( block, "size", 2560 * 4 );
  swr_sdb_set_config_double( block, "sigma", 450 );
#if BYPASS

  PR( "Bypassing, just to show how it works w/o LDPC\n" );
  swr_sdb_send_msg( rand, SUBS_MSG_USER, NULL, -1 );
  return 0;
#endif


  swr_sdb_set_config_int( decode, "iterations", 30 );
  swr_sdb_set_config_int( decode, "channel_type", 2 );
  // Here we take the channel_param from mafi. I.e.  a/variance
  // is not 1/15 but computed in ldpc_decode with the values taken from midamble_rcv
  swr_sdb_set_config_int( decode, "mafi", mafi_id );


  for ( i=1; i<=3; i++ ) {
    swr_sdb_set_config_int( encode, "ldpc_code_id", i );
    swr_sdb_set_config_int( decode, "ldpc_code_id", i );
    // Tell the random-module to produce a block of random-data which will
    // be propagated to the encode and decode module and finish in the sink.
    PR( "Sending with code %i\n", i );
    swr_sdb_send_msg( rand, SUBS_MSG_USER, NULL, -1 );
    PR( "Encountered SNR is: %g\n",
        swr_sdb_get_stats_double( mafi_id, "snr" ) );
    swr_sdb_show_profile( encode );
    swr_sdb_show_profile( decode );
    swr_sdb_clear_profile( encode );
    swr_sdb_clear_profile( decode );
  }

  // After this call, the chain has been walked through
  usleep( 1000000 );

  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 );