sdrangel/plugins/channeltx/moddatv/dvb-s2/DVBS2.cpp

///////////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2021 Jon Beniston, M7RCE <jon@beniston.com>                         //
//                                                                                   //
// 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 as version 3 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 V3 for more details.                                   //
//                                                                                   //
// You should have received a copy of the GNU General Public License                 //
// along with this program. If not, see <http://www.gnu.org/licenses/>.              //
///////////////////////////////////////////////////////////////////////////////////////
#include "memory.h"
#include "DVBS2.h"

//
// called at the end of a frame
//
void  DVBS2::end_of_frame_actions(void)
{
    if( m_s2_config_updated )
    {
        modulator_configuration();
        m_s2_config_updated = 0;
    }
}

int DVBS2::is_valid( int mod, int coderate )
{
    if( mod == M_QPSK )
    {
        if(coderate == CR_1_4)  return 0;
        if(coderate == CR_1_3)  return 0;
        if(coderate == CR_2_5)  return 0;
        if(coderate == CR_1_2)  return 0;
        if(coderate == CR_3_5)  return 0;
        if(coderate == CR_2_3)  return 0;
        if(coderate == CR_3_4)  return 0;
        if(coderate == CR_4_5)  return 0;
        if(coderate == CR_5_6)  return 0;
        if(coderate == CR_8_9)  return 0;
        if(coderate == CR_9_10) return 0;
    }
    if( mod == M_8PSK )
    {
        if(coderate == CR_3_5)  return 0;
        if(coderate == CR_2_3)  return 0;
        if(coderate == CR_3_4)  return 0;
        if(coderate == CR_5_6)  return 0;
        if(coderate == CR_8_9)  return 0;
        if(coderate == CR_9_10) return 0;
    }
    if( mod == M_16APSK )
    {
        if(coderate == CR_2_3)  return 0;
        if(coderate == CR_3_4)  return 0;
        if(coderate == CR_4_5)  return 0;
        if(coderate == CR_5_6)  return 0;
        if(coderate == CR_8_9)  return 0;
        if(coderate == CR_9_10) return 0;
    }
    if( mod == M_32APSK )
    {
        if(coderate == CR_3_4)  return 0;
        if(coderate == CR_4_5)  return 0;
        if(coderate == CR_5_6)  return 0;
        if(coderate == CR_8_9)  return 0;
        if(coderate == CR_9_10) return 0;
    }
    return -1;
}
//
// index 0 and 1 will only be different when being reconfigured.
// Use index 1 as this will be applied in the following transmit
// frames
//
void DVBS2::calc_efficiency( void )
{
    double p,m,a,s,b,po;
    // Calculate the number of symbols in the payload
    p = 0;a = 0; m = 0;
    if( m_format[1].frame_type == FRAME_NORMAL )  p = (double)FRAME_SIZE_NORMAL;
    if( m_format[1].frame_type == FRAME_SHORT  )  p = (double)FRAME_SIZE_SHORT;
    if( m_format[1].constellation == M_QPSK )     m = 2.0;
    if( m_format[1].constellation == M_8PSK )     m = 3.0;
    if( m_format[1].constellation == M_16APSK )   m = 4.0;
    if( m_format[1].constellation == M_32APSK )   m = 5.0;
    s = p/m;//Number of symbols per frame
    // PL header overhead
    if( m_format[1].pilots )
    {
        po = (s/(90*16))-1;// 1 pilot every 16 blocks (of 90 symbols)
        po = po*36;        // No pilot at the end
        a  = s/(90+po+s);
    }
    else
    {
        a = s/(90+s);// No pilots
    }
    // Modulation efficiency
    a = a*m;
    // Take into account pilot symbols
    // TBD
    // Now calculate the usable data as percentage of the frame
    b = ((double)m_format[1].useable_data_bits)/p;
    // Now calculate the efficiency by multiplying the
    // usable bits efficiency by the modulation efficiency
    m_efficiency = b*a;
}
//
// Multiply the efficiency value by the symbol rate
// to get the usable bitrate
//
double DVBS2::s2_get_efficiency( void )
{
    return m_efficiency;
}

int DVBS2::s2_set_configure( DVB2FrameFormat *f )
{
    if( is_valid( f->constellation, f->code_rate ) == 0 )
    {
        if( set_configure( f ) == 0 )
        {
             calc_efficiency();
             m_s2_config_updated = 1;
			 m_configured = 1;

             return 0;
        }
    }
    return -1;
}
void DVBS2::s2_get_configure( DVB2FrameFormat *f )
{
    get_configure( f );
}
int DVBS2::s2_add_ts_frame( u8 *ts )
{
    int res = 0;
	if (m_configured == 0) return 0;
    // Call base class
    if( next_ts_frame_base( ts ) )
    {
        // Interleave and pack
        s2_interleave();
        // create the header
        s2_pl_header_create();
        // Add the data
        res = s2_pl_data_pack();
        // Do any updates required for the next frame
        end_of_frame_actions();
    }
    return res;
}
void DVBS2::physical( void )
{

}

DVBS2::DVBS2()
{
	m_configured = 0;
    modulator_configuration();
    build_symbol_scrambler_table();
    pl_build_dummy();
}