poly_phase.c

在linux系统下开发研究移动通信的工具型代码

/*
 * $Log: poly_phase.c,v $
 * Revision 1.1  2000/05/03 14:30:04  bjc97r
 * Initial revision
 *
 *
 */

char *_poly_phase_id = "$Id: poly_phase.c,v 1.1 2000/05/03 14:30:04 bjc97r Exp $";


#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "walsh.h"
#include "ogold.h"

char *PPClass_text[] = {
  "None",
  "Zadoff-Chu",
  "Frank",
  "OGold",
  "Walsh",
  "QOGold",
  "QWalsh"
};

char *PPClass_text1 = "nzfowOW";

void frank_seq( float phase[], int N, int p )
     /* Generate a Frank sequence of length N.
	The generated code phase sequence is stored in phase[k], k=0..(N-1)
        sqrt(N) is the order,
        p is coprime to sqrt(N) */
{
  int i, j;
  
  N = sqrt(N);
  for( i = 0; i < N; i++ ) {
    for( j = 0; j < N; j++ ) {
      phase[i+N*j] = 2.*M_PI/N*((p*i*j)%N);
    }
  }
}

void zadoff_chu_seq( float phase[], int N, int p )
     /* Generate a Zadoff-Chu sequence of length N.
	The generated code phase sequence is stored in phase[k], k=0..(N-1)
        N is the order,
        p is coprime to N */
{
  int i;

  if (N & 1) { /* Odd N */
    for( i = 0; i < N; i++ ) {
      phase[i] = M_PI/N*p*i*(i+1);
    }
  }
  else { /* Even N */
    for( i = 0; i < N; i++ ) {
      phase[i] = M_PI/N*p*i*i;
    }
  }
}



void circular_shift( float val[], int N, int k )
     /* Do a circular shift val[0..(N-1)] by k. */
{
  int i;
  float *temp;

  temp = malloc( N*sizeof(float) );
  memcpy( temp, val, N*sizeof(float) );

  for( i = 0; i < k; i++ )
    val[i] = temp[N-k+i];
  for( i = 0; i < (N-k); i++ )
    val[k+i] = temp[i];

  free(temp);
}

void circular_shift2( float dest[], float src[], int N, int k )
     /* Do a circular shift src[0..(N-1)] by k
	and store the result at dest[]. */
{
  int i;

  for( i = 0; i < k; i++ )
    dest[i] = src[N-k+i];
  for( i = 0; i < (N-k); i++ )
    dest[k+i] = src[i];
}

void qwalsh( float phase[], int N, int index )
     /* Generate quadratic Walsh codes using the reverse sequences as
	quadrature sequences.
	N is the size,
	index is the walsh index */
{
  int i;
  Walsh *id;
  int *code = (int*) malloc( N * sizeof(int) );
  float PI1Q = M_PI / 4.;
  float PI3Q = 3. * M_PI / 4.;

  id = walsh_create( index, 0);
  for( i = 0; i < N; i++ ) code[i] = walsh( id );
  walsh_free( id );

  for( i = 0; i < N; i++ ) {
    phase[i] = code[i] ? PI1Q : PI3Q;
    if ( !code[N-i-1] )
      phase[i] *= -1.;
  }
  free( code );
}

void qogold( float phase[], int N, int deg, int p0, int p1, int index )
     /* Generate quadratic OGold codes using the reverse sequences as
	quadrature sequences.
	N is the size,
	index is the ogold index */
{
  int i;
  OGold *id;
  int *code = (int*) malloc( N * sizeof(int) );
  float PI1Q = M_PI / 4.;
  float PI3Q = 3. * M_PI / 4.;

  id = ogold_create( (unsigned) deg, (unsigned long)p0, (unsigned long)p1,
		     (unsigned long)index );
  for( i = 0; i < N; i++ ) code[i] = ogold( id );
  ogold_free( id );

  for( i = 0; i < N; i++ ) {
    phase[i] = code[i] ? PI1Q : PI3Q;
    if ( !code[N-i-1] )
      phase[i] *= -1.;
  }
  free( code );
}