discdemod.c

来自「wcdma模型」· C语言 代码 · 共 118 行

/*
 |
 | Copyright disclaimer:
 |   This software was developed at the National Institute of Standards
 |   and Technology by employees of the Federal Government in the course
 |   of their official duties. Pursuant to title 17 Section 105 of the
 |   United States Code this software is not subject to copyright
 |   protection and is in the public domain.
 |
 |   We would appreciate acknowledgement if the software is used.
 |
*/

/*
 | Project:     WCDMA simulation environment
 | Module:      Discrete CDMA downlink demodulation containing QPSK data 
 |		and spreading modulation.
 |		No multipath, i.e. ideal channel and synchronisation.
 | Author:      Tommi Makelainen, Nokia/NIST
 | Date:        February 23, 1999
 |
 | History:
 |              February 23, 1999 Tommi Makelainen
 |                      Initial version.
 |
 |              April 6, 1999 Tommi Makelainen
 |                      Modified despreader name.
 |
 */

#include <stdio.h>
#include <math.h>
#include "conversions.h"
#include "bitroutines.h"
#include "config_wcdma.h"
#include "mealy.h"
#include "spreading.h"
#include "qpsk_ints.h"
#include "discdemod.h"


/* ------------------------------------------------------------------- */

/*
 * Function:    wcdma_demod_init
 * Desc.:       Discrete data and spreading demodulation initialization.
 *
 * Note:
 */
int wcdma_demod_init(void)
{

    /*
     * Allocated memory for temporary outputs.
     */

    return(0);
}

/* -------------------------------------------------------------------- */

/*
 * Function:    wcdma_dl_demod
 * Desc.:       Data and spreading modulation
 *
 * Note:
 *		Input data length can be maximum of 4000 symbols.
 *		Output vector length is:
 *			nInputs / sf * 2
 */
int wcdma_dl_demod(int I_inputs[],	/* I input symbol vector */
		       int Q_inputs[],	/* Q input symbol vector */
                       int nInputs,	/* input vector size */
                       int code[],      /* spreading code */
                       int code_len,	/* length of spreading code */
                       int sf,		/* spreadign factor */
                       int coded_out[])	/* channel coded output */
{
    int mod_data_len, coded_data_len;
    int data_out[2000];
    int I_out[2000], Q_out[2000];

    /*
     * Despread I and Q channels separately.
     */
    wcdma_hard_despread(I_inputs, nInputs, code, code_len, sf, data_out);
    antipodal2bin(data_out, nInputs/sf, I_out);
    wcdma_hard_despread(Q_inputs, nInputs, code, code_len, sf, data_out);
    antipodal2bin(data_out, nInputs/sf, Q_out);

    /*
     * Demodulate data, i.e. de-multiplex I and Q.
     */
    mod_data_len = nInputs / sf;
    wcdma_dl_qpsk_demod(I_out, Q_out, mod_data_len,
                        coded_out, &coded_data_len);

    return(0);
}

/* -------------------------------------------------------------------- */

/*
 * Function:    wcdma_dl_demod_free
 * Desc.:       Discrete modulation clean up function.
 *
 * Note:
 */
int wcdma_dl_demod_free(void)
{
    return(0);
}


/* -------------------------------------------------------------------- */