convenc.c

这是一个c＋＋编写的WCDMA链路采用RAKE接收的方针源代码

/*
 | Project:     WCDMA simulation environment
 | Module:      Convolutional encoder
 | Author:      Tommi Makelainen
 | Date:        January 12, 1999
 |
 | History:
 |              January 12, 1999 Tommi Makelainen
 |                      Modified C. Britton Rorabaugh's example code
 |			to rate 1/3 and 1/2 codes with constraint length
 |			K=9 (i.e. length of memory shift register).
 |
 | 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.
 |
 */

#include <stdlib.h>
#include <math.h>
#include <ctype.h>
#include <string.h> 
#include <stdio.h>
#include "utility.h"   
#include "mealy.h"
#include "errormsg.h"
#include "config_wcdma.h"


/* ------------------------------------------------------------------- */
/*
 * Function:    wcdma_R1o3_k9_conv_init
 * Desc.:       Extract given single bit value from a given byte.
 *
 * Note:
 *		Generator polynomial are handled as bit masks.
 */
void wcdma_R1o3_k9_conv_init(
		MealyEncoder* this,	/* IN: data store for transitions */
		int num_stages, 	/* IN: length of shift register */
		int gen_poly_1,		/* IN: gen. polynomial for output 1 */
		int gen_poly_2,		/* IN: gen. polynomial for output 2 */
		int gen_poly_3		/* IN: gen. polynomial for output 3 */
 	        )
{
  int shift_register;
  int num_states;
  int current_state, input;
  int output_1, output_2, output_3, output;
  int input_bit;

  num_states = IntPower(2, num_stages-1);
  this->Max_Input = 1;
  this->Max_State = num_states-1;

  for(current_state=0; current_state<num_states; current_state++) {
      for(input=0; input<=1; input++) {
	shift_register = current_state;
	input_bit = input<<(num_stages-1);
	shift_register +=input_bit;
	output_1 = Parity(gen_poly_1 & shift_register);
	output_2 = Parity(gen_poly_2 & shift_register);
	output_3 = Parity(gen_poly_3 & shift_register);
	output = (output_1<<2) + (output_2<<1) + output_3;
	this->Output_Symbol[current_state][input] = output;
	this->Next_State[current_state][input] = shift_register>>1;
#ifdef WCDMA_DEBUG_OUTPUT
	printf("state = %d  input = %d  out = %d  next = %d\n", current_state,
			input, output, this->Next_State[current_state][input]);
#endif /* WCDMA_DEBUG_OUTPUT */
      } /* end of input loop  */
  } /* end of current_state loop */
  return;
};


/* ------------------------------------------------------------------- */
/*
 * Function:    wcdma_R1o3_k9_conv_enc
 * Desc.:       Perform convolutional encoding for input vector.
 *
 * Note:
 */
int wcdma_R1o3_k9_conv_enc(	MealyEncoder* this, /* IN: encoder data */
				int input_size,     /* IN: input vector len */
				int input[],        /* IN: input data */
				int output[],       /* OUT: output data */
				int tail[])         /* OUT: tail bits */
{
  int i, current_state, out_index, tail_len, index;

  current_state = 0;
  for (i=0; i < input_size; i++) {
    index = input[i];
    output[i] = this->Output_Symbol[current_state][index];
    current_state = this->Next_State[current_state][index];
    out_index = i;
  }
  tail_len = CONVOLUTION_TAIL_LEN;
  for (i=0; i < tail_len; i++) {
    /* tail[i] = 0; */
    tail[i] = (current_state >> i) & 0x1;
  }

  return(0);
}; 


/* ------------------------------------------------------------------- */
/*
 * Function:    wcdma_R1o2_k9_conv_init
 * Desc.:       Initialize convolutional coder 1/2 memory length 9.
 *
 * Note:
 *		Generator polynomial are handled as bit masks.
 */
void wcdma_R1o2_k9_conv_init(
		MealyEncoder* this,	/* IN: data store for transitions */
		int num_stages, 	/* IN: length of shift register */
		int gen_poly_1,		/* IN: gen. polynomial for output 1 */
		int gen_poly_2		/* IN: gen. polynomial for output 2 */
 	        )
{
  int shift_register;
  int num_states;
  int current_state, input;
  int output_1, output_2, output;
  int input_bit;

  num_states = IntPower(2, num_stages-1);
  this->Max_Input = 1;
  this->Max_State = num_states-1;

  for(current_state=0; current_state<num_states; current_state++) {
      for(input=0; input<=1; input++) {
	shift_register = current_state;
	input_bit = input<<(num_stages-1);
	shift_register +=input_bit;
	output_1 = Parity(gen_poly_1 & shift_register);
	output_2 = Parity(gen_poly_2 & shift_register);
	output = (output_1<<1) + output_2;
	this->Output_Symbol[current_state][input] = output;
	this->Next_State[current_state][input] = shift_register>>1;
#ifdef WCDMA_DEBUG_OUTPUT
	printf("state = %d  input = %d  out = %d  next = %d\n", current_state,
			input, output, this->Next_State[current_state][input]);
#endif /* WCDMA_DEBUG_OUTPUT */
      } /* end of input loop  */
  } /* end of current_state loop */
  return;
};


/* ------------------------------------------------------------------- */
/*
 * Function:    wcdma_R1o2_k9_conv_enc
 * Desc.:       Perform convolutional encoding 1/2 for input vector.
 *
 * Note:
 */
int wcdma_R1o2_k9_conv_enc(	MealyEncoder* this, /* IN: encoder data */
				int input_size,     /* IN: input vector len */
				int input[],        /* IN: input data */
				int output[],       /* OUT: output data */
				int tail[])         /* OUT: tail bits */
{
  int i, current_state, out_index, tail_len, index;

  current_state = 0;
  for (i=0; i < input_size; i++) {
    index = input[i];
    output[i] = this->Output_Symbol[current_state][index];
    current_state = this->Next_State[current_state][index];
    out_index = i;
  }
  tail_len = CONVOLUTION_TAIL_LEN;
  for (i=0; i < tail_len; i++) {
    tail[i] = (current_state >> i) & 0x1;
  }

  return(0);
}; 


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