mirror of
https://github.com/dj0abr/SSB_HighSpeed_Modem.git
synced 2024-11-22 04:10:19 -05:00
117 lines
3.7 KiB
C++
Executable File
117 lines
3.7 KiB
C++
Executable File
/*
|
|
* High Speed modem to transfer data in a 2,7kHz SSB channel
|
|
* =========================================================
|
|
* Author: DJ0ABR
|
|
*
|
|
* (c) DJ0ABR
|
|
* www.dj0abr.de
|
|
*
|
|
* 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.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*
|
|
*/
|
|
|
|
#include "hsmodem.h"
|
|
|
|
|
|
#include <cstddef>
|
|
#include <iostream>
|
|
#include <string>
|
|
|
|
#include "fec/schifra_galois_field.hpp"
|
|
#include "fec/schifra_galois_field_polynomial.hpp"
|
|
#include "fec/schifra_sequential_root_generator_polynomial_creator.hpp"
|
|
#include "fec/schifra_reed_solomon_encoder.hpp"
|
|
#include "fec/schifra_reed_solomon_decoder.hpp"
|
|
#include "fec/schifra_reed_solomon_block.hpp"
|
|
#include "fec/schifra_error_processes.hpp"
|
|
|
|
/* Finite Field Parameters */
|
|
const std::size_t field_descriptor = 8;
|
|
const std::size_t generator_polynomial_index = 120;
|
|
const std::size_t generator_polynomial_root_count = FECLEN;
|
|
|
|
/* Reed Solomon Code Parameters */
|
|
const std::size_t code_length = FECBLOCKLEN;
|
|
const std::size_t fec_length = FECLEN;
|
|
const std::size_t data_length = code_length - fec_length;
|
|
|
|
/* Instantiate Finite Field and Generator Polynomials */
|
|
const schifra::galois::field field(field_descriptor,
|
|
schifra::galois::primitive_polynomial_size06,
|
|
schifra::galois::primitive_polynomial06);
|
|
|
|
schifra::galois::field_polynomial generator_polynomial(field);
|
|
|
|
/* Instantiate Encoder and Decoder (Codec) */
|
|
typedef schifra::reed_solomon::encoder<code_length,fec_length,data_length> encoder_t;
|
|
typedef schifra::reed_solomon::decoder<code_length,fec_length,data_length> decoder_t;
|
|
|
|
|
|
|
|
|
|
int cfec_Reconstruct(uint8_t *darr, uint8_t *destination)
|
|
{
|
|
schifra::reed_solomon::block<code_length,fec_length> rxblock;
|
|
|
|
for(std::size_t i=0; i<code_length; i++)
|
|
rxblock.data[i] = darr[i];
|
|
|
|
const decoder_t decoder(field, generator_polynomial_index);
|
|
if (!decoder.decode(rxblock))
|
|
{
|
|
// FEC decoding not possible
|
|
return 0;
|
|
}
|
|
|
|
for(std::size_t i=0; i<data_length; i++)
|
|
destination[i] = rxblock[i];
|
|
|
|
return 1;
|
|
}
|
|
|
|
void GetFEC(uint8_t *txblock, int len, uint8_t *destArray)
|
|
{
|
|
schifra::reed_solomon::block<code_length,fec_length> block;
|
|
|
|
// fill payload into an FEC-block
|
|
for(std::size_t i=0; i<data_length; i++)
|
|
block.data[i] = txblock[i];
|
|
|
|
/* Transform message into Reed-Solomon encoded codeword */
|
|
const encoder_t encoder(field, generator_polynomial);
|
|
if (!encoder.encode(block))
|
|
{
|
|
// encoding not possible, should never happen
|
|
return;
|
|
}
|
|
|
|
// get result out of the FEC block
|
|
for(std::size_t i=0; i<code_length; i++)
|
|
destArray[i] = block[i];
|
|
}
|
|
|
|
void initFEC()
|
|
{
|
|
if (!schifra::make_sequential_root_generator_polynomial( field,
|
|
generator_polynomial_index,
|
|
generator_polynomial_root_count,
|
|
generator_polynomial))
|
|
{
|
|
std::cout << "Error - Failed to create sequential root generator!" << std::endl;
|
|
return;
|
|
}
|
|
}
|
|
|