satellite-wave-form-conf.cc

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013 Magister Solutions Ltd
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Sami Rantanen <sami.rantanen@magister.fi>
 */
 
#include "satellite-wave-form-conf.h"
 
#include "satellite-const-variables.h"
#include "satellite-link-results.h"
#include "satellite-utils.h"
 
#include "ns3/boolean.h"
#include "ns3/double.h"
#include "ns3/enum.h"
#include "ns3/log.h"
#include "ns3/satellite-env-variables.h"
#include "ns3/singleton.h"
#include "ns3/uinteger.h"
 
#include <algorithm>
#include <cmath>
#include <fstream>
#include <iostream>
#include <limits>
#include <map>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
 
NS_LOG_COMPONENT_DEFINE("SatWaveformConf");
 
namespace ns3
{
 
SatWaveform::SatWaveform()
    : m_waveformId(0),
      m_modulatedBits(0),
      m_codingRate(0.0),
      m_modCod(SatEnums::SAT_NONVALID_MODCOD),
      m_payloadBytes(0),
      m_lengthInSymbols(0),
      m_preambleLengthInSymbols(0),
      m_ebnoRequirement(0.0)
{
    NS_ASSERT(false);
}
 
SatWaveform::SatWaveform(uint32_t wfId,
                         uint32_t modulatedBits,
                         double codingRate,
                         SatEnums::SatModcod_t modcod,
                         uint32_t payloadBytes,
                         uint32_t lengthInSymbols,
                         uint32_t preambleLengthInSymbols)
    : m_waveformId(wfId),
      m_modulatedBits(modulatedBits),
      m_codingRate(codingRate),
      m_modCod(modcod),
      m_payloadBytes(payloadBytes),
      m_lengthInSymbols(lengthInSymbols),
      m_preambleLengthInSymbols(preambleLengthInSymbols),
      m_ebnoRequirement(0.0)
{
}
 
uint32_t
SatWaveform::GetWaveformId() const
{
    NS_LOG_FUNCTION(this);
    return m_waveformId;
}
 
SatEnums::SatModcod_t
SatWaveform::GetModCod() const
{
    NS_LOG_FUNCTION(this);
    return m_modCod;
}
 
uint32_t
SatWaveform::GetPayloadInBytes() const
{
    NS_LOG_FUNCTION(this);
    return m_payloadBytes;
}
 
uint32_t
SatWaveform::GetBurstLengthInSymbols() const
{
    NS_LOG_FUNCTION(this);
    return m_lengthInSymbols;
}
 
uint32_t
SatWaveform::GetPreambleLengthInSymbols() const
{
    NS_LOG_FUNCTION(this);
    return m_preambleLengthInSymbols;
}
 
Time
SatWaveform::GetBurstDuration(double symbolRateInBaud) const
{
    NS_LOG_FUNCTION(this << symbolRateInBaud);
    return Seconds(m_lengthInSymbols / symbolRateInBaud);
}
 
Time
SatWaveform::GetPreambleDuration(double symbolRateInBaud) const
{
    NS_LOG_FUNCTION(this << symbolRateInBaud);
    return Seconds(m_preambleLengthInSymbols / symbolRateInBaud);
}
 
double
SatWaveform::GetSpectralEfficiency(double carrierBandwidthInHz, double symbolRateInBaud) const
{
    NS_LOG_FUNCTION(this << carrierBandwidthInHz << symbolRateInBaud);
    return (SatConstVariables::BITS_PER_BYTE * m_payloadBytes) /
           (m_lengthInSymbols / symbolRateInBaud) / carrierBandwidthInHz;
}
 
double
SatWaveform::GetThroughputInBitsPerSecond(double symbolRateInBaud) const
{
    NS_LOG_FUNCTION(this << symbolRateInBaud);
    return SatConstVariables::BITS_PER_BYTE * m_payloadBytes /
           (m_lengthInSymbols / symbolRateInBaud);
}
 
double
SatWaveform::GetCNoThreshold(double symbolRateInBaud) const
{
    NS_LOG_FUNCTION(this << symbolRateInBaud);

    double cnoRequirement = m_ebnoRequirement * symbolRateInBaud * m_codingRate * m_modulatedBits;
 
    return cnoRequirement;
}
 
void
SatWaveform::SetEbNoRequirement(double ebnoRequirement)
{
    NS_LOG_FUNCTION(this << ebnoRequirement);
    m_ebnoRequirement = ebnoRequirement;
}
 
void
SatWaveform::Dump(double carrierBandwidthInHz, double symbolRateInBaud) const
{
    NS_LOG_FUNCTION(this << carrierBandwidthInHz << symbolRateInBaud);
 
    std::cout << "ModulatedBits: " << m_modulatedBits << ", CodingRate: " << m_codingRate
              << ", Payload: " << m_payloadBytes << ", BurstLength: " << m_lengthInSymbols
              << ", EbNoRequirement: " << SatUtils::LinearToDb(m_ebnoRequirement)
              << ", BurstDuration: " << GetBurstDuration(symbolRateInBaud)
              << ", Throughput: " << GetThroughputInBitsPerSecond(symbolRateInBaud)
              << ", SpectralEfficiency: "
              << GetSpectralEfficiency(carrierBandwidthInHz, symbolRateInBaud)
              << ", C/No threshold: " << SatUtils::LinearToDb(GetCNoThreshold(symbolRateInBaud))
              << std::endl;
}
 
NS_OBJECT_ENSURE_REGISTERED(SatWaveformConf);
 
SatWaveformConf::SatWaveformConf()
    : m_waveforms(),
      m_targetBLER(0.00001),
      m_acmEnabled(false),
      m_defaultWfId(3),
      m_minWfId(0),
      m_maxWfId(23),
      m_burstLength(SatEnums::UNKNOWN_BURST)
{
    // default constructor should not be used
    NS_ASSERT(false);
}
 
SatWaveformConf::SatWaveformConf(std::string directoryPathName)
    : m_waveforms(),
      m_targetBLER(0.00001),
      m_acmEnabled(false),
      m_defaultWfId(3),
      m_minWfId(0),
      m_maxWfId(23),
      m_burstLength(SatEnums::UNKNOWN_BURST)
{
    NS_LOG_FUNCTION(this << directoryPathName);
 
    if (!SatEnvVariables::GetInstance()->IsValidDirectory(directoryPathName))
    {
        NS_FATAL_ERROR("No such directory: " << directoryPathName);
    }
 
    std::string waveformsFilePathName = directoryPathName + "/waveforms.txt";
    std::string defaultWaveform = directoryPathName + "/default_waveform.txt";
 
    ReadFromFile(waveformsFilePathName);
    ReadFromFileDefaultWaveform(defaultWaveform);
}
 
void
SatWaveformConf::NotifyConstructionCompleted()
{
    NS_LOG_FUNCTION(this);
 
    Object::NotifyConstructionCompleted();
 
    switch (m_burstLength)
    {
    case SatEnums::SHORT_BURST:
        m_supportedBurstLengthsInSymbols.push_back((uint32_t)SHORT_BURST_LENGTH);
        break;
    case SatEnums::LONG_BURST:
        m_supportedBurstLengthsInSymbols.push_back((uint32_t)LONG_BURST_LENGTH);
        break;
    case SatEnums::SHORT_AND_LONG_BURST:
        m_supportedBurstLengthsInSymbols.push_back((uint32_t)SHORT_BURST_LENGTH);
        m_supportedBurstLengthsInSymbols.push_back((uint32_t)LONG_BURST_LENGTH);
        break;
    default:
        NS_FATAL_ERROR("Incorrect choice of burst length.");
    }
}
 
TypeId
SatWaveformConf::GetTypeId(void)
{
    static TypeId tid = TypeId("ns3::SatWaveformConf")
                            .SetParent<Object>()
                            .AddAttribute("TargetBLER",
                                          "Block error rate target",
                                          DoubleValue(0.00001),
                                          MakeDoubleAccessor(&SatWaveformConf::m_targetBLER),
                                          MakeDoubleChecker<double>())
                            .AddAttribute("AcmEnabled",
                                          "Enable ACM",
                                          BooleanValue(false),
                                          MakeBooleanAccessor(&SatWaveformConf::m_acmEnabled),
                                          MakeBooleanChecker())
                            .AddAttribute("BurstLength",
                                          "Default burst length",
                                          EnumValue(SatEnums::SHORT_AND_LONG_BURST),
                                          MakeEnumAccessor<SatEnums::SatWaveFormBurstLength_t>(
                                              &SatWaveformConf::m_burstLength),
                                          MakeEnumChecker(SatEnums::SHORT_BURST,
                                                          "ShortBurst",
                                                          SatEnums::LONG_BURST,
                                                          "LongBurst",
                                                          SatEnums::SHORT_AND_LONG_BURST,
                                                          "ShortAndLongBurst"))
                            .AddConstructor<SatWaveformConf>();
    return tid;
}
 
SatWaveformConf::~SatWaveformConf()
{
    NS_LOG_FUNCTION(this);
}
 
void
SatWaveformConf::ReadFromFileDefaultWaveform(std::string filePathName)
{
    NS_LOG_FUNCTION(this << filePathName);
 
    // READ FROM THE SPECIFIED INPUT FILE
    std::ifstream* ifs = new std::ifstream(filePathName.c_str(), std::ifstream::in);
 
    if (!ifs->is_open())
    {
        // script might be launched by test.py, try a different base path
        delete ifs;
        filePathName = "../../" + filePathName;
        ifs = new std::ifstream(filePathName.c_str(), std::ifstream::in);
 
        if (!ifs->is_open())
        {
            NS_FATAL_ERROR("The file " << filePathName << " is not found.");
        }
    }
 
    // Read line by line
    std::string line;
    std::getline(*ifs, line);
    std::istringstream line_ss(line);
    if (!(line_ss >> m_defaultWfId))
    {
        NS_FATAL_ERROR("SatWaveformConf::ReadFromFileDefaultWaveform - Waveform conf vector has "
                       "unexpected amount of elements!");
    }
}
 
void
SatWaveformConf::ReadFromFile(std::string filePathName)
{
    NS_LOG_FUNCTION(this << filePathName);
 
    std::vector<uint32_t> wfIds;
 
    // READ FROM THE SPECIFIED INPUT FILE
    std::ifstream* ifs = new std::ifstream(filePathName.c_str(), std::ifstream::in);
 
    if (!ifs->is_open())
    {
        // script might be launched by test.py, try a different base path
        delete ifs;
        filePathName = "../../" + filePathName;
        ifs = new std::ifstream(filePathName.c_str(), std::ifstream::in);
 
        if (!ifs->is_open())
        {
            NS_FATAL_ERROR("The file " << filePathName << " is not found.");
        }
    }
 
    // Row vector containing the waveform information for a certain waveform index
    std::vector<double> rowVector;
 
    // Start conditions
    int32_t wfIndex, modulatedBits, payloadBytes, durationInSymbols, preambleDurationInSymbols;
    std::string sCodingRate;
 
    // Read line by line
    std::string line;
 
    while (std::getline(*ifs, line))
    {
        std::istringstream line_ss(line);
 
        // Unpack values
        if (!(line_ss >> wfIndex >> modulatedBits >> sCodingRate >> payloadBytes >>
              durationInSymbols))
        {
            NS_FATAL_ERROR("SatWaveformConf::ReadFromFile - Waveform conf vector has unexpected "
                           "amount of elements!");
        }
        // Try to unpack preambule duration
        if (!(line_ss >> preambleDurationInSymbols))
        {
            preambleDurationInSymbols = 0;
        }
 
        // Store temporarily all wfIds
        wfIds.push_back(wfIndex);
 
        // Convert the coding rate fraction into double
        std::istringstream ss(sCodingRate);
        std::string token;
        std::vector<uint32_t> output;
 
        while (std::getline(ss, token, '/'))
        {
            uint32_t i;
            std::stringstream s;
            s.str(token);
            s >> i;
            output.push_back(i);
        }
 
        if (output.size() != 2)
        {
            NS_FATAL_ERROR("SatWaveformConf::ReadFromFile - Temp fraction vector has unexpected "
                           "amount of elements!");
        }
 
        double dCodingRate = double(output[0]) / output[1];
 
        // Convert modulated bits and coding rate to MODCOD enum
        SatEnums::SatModcod_t modcod = ConvertToModCod(modulatedBits, output[0], output[1]);
 
        // Create new waveform and insert it to the waveform map
        Ptr<SatWaveform> wf = Create<SatWaveform>(wfIndex,
                                                  modulatedBits,
                                                  dCodingRate,
                                                  modcod,
                                                  payloadBytes,
                                                  durationInSymbols,
                                                  preambleDurationInSymbols);
        m_waveforms.insert(std::make_pair(wfIndex, wf));
    }
 
    ifs->close();
    delete ifs;
 
    // Note, currently we assume that the waveform ids are consecutive!
    m_minWfId = *std::min_element(wfIds.begin(), wfIds.end());
    m_maxWfId = *std::max_element(wfIds.begin(), wfIds.end());
}
 
void
SatWaveformConf::InitializeEbNoRequirements(Ptr<SatLinkResultsRtn> linkResults)
{
    NS_LOG_FUNCTION(this);
 
    for (std::map<uint32_t, Ptr<SatWaveform>>::iterator it = m_waveforms.begin();
         it != m_waveforms.end();
         ++it)
    {
        double ebnoRequirementDb = linkResults->GetEbNoDb(it->first, m_targetBLER);
        it->second->SetEbNoRequirement(SatUtils::DbToLinear(ebnoRequirementDb));
    }
}
 
Ptr<SatWaveform>
SatWaveformConf::GetWaveform(uint32_t wfId) const
{
    NS_LOG_FUNCTION(this << wfId);
 
    if (m_minWfId > wfId || wfId > m_maxWfId)
    {
        NS_FATAL_ERROR("SatWaveformConf::GetWaveform - unsupported waveform id: " << wfId);
    }
 
    return m_waveforms.at(wfId);
}
 
uint32_t
SatWaveformConf::GetDefaultWaveformId() const
{
    NS_LOG_FUNCTION(this << m_defaultWfId);
 
    if (m_minWfId > m_defaultWfId || m_defaultWfId > m_maxWfId)
    {
        NS_FATAL_ERROR(
            "SatWaveformConf::GetDefaultWaveformId - unsupported waveform id: " << m_defaultWfId);
    }
 
    return m_defaultWfId;
}
 
bool
SatWaveformConf::GetBestWaveformId(double cno,
                                   double symbolRateInBaud,
                                   uint32_t& wfId,
                                   double& cnoThreshold,
                                   uint32_t burstLength) const
{
    NS_LOG_FUNCTION(this << cno << symbolRateInBaud << wfId << cnoThreshold << burstLength);
 
    bool success = false;
 
    // If ACM is disabled, return the default waveform
    if (!m_acmEnabled || std::isnan(cno))
    {
        wfId = m_defaultWfId;
        success = true;
        return success;
    }
 
    // Return the waveform with best spectral efficiency
    for (std::map<uint32_t, Ptr<SatWaveform>>::const_reverse_iterator rit = m_waveforms.rbegin();
         rit != m_waveforms.rend();
         ++rit)
    {
        if (rit->second->GetBurstLengthInSymbols() == burstLength)
        {
            double cnoThr = rit->second->GetCNoThreshold(symbolRateInBaud);
            // The first waveform over the threshold
            if (cnoThr <= cno)
            {
                wfId = rit->first;
                cnoThreshold = cnoThr;
                success = true;
                break;
            }
        }
    }
 
    NS_LOG_INFO("Get best waveform in RTN link (ACM)! CNo: "
                << SatUtils::LinearToDb(cno) << ", Symbol rate: " << symbolRateInBaud
                << ", burst length: " << burstLength << ", WF: " << wfId
                << ", CNo threshold: " << SatUtils::LinearToDb(cnoThreshold));
 
    return success;
}
 
bool
SatWaveformConf::GetMostRobustWaveformId(uint32_t& wfId, uint32_t burstLength) const
{
    NS_LOG_FUNCTION(this << burstLength);
 
    bool found = false;
 
    uint32_t payloadInBytes = std::numeric_limits<uint32_t>::max();
 
    // find the waveform with the more robust waveform than previous one
    for (std::map<uint32_t, Ptr<SatWaveform>>::const_reverse_iterator rit = m_waveforms.rbegin();
         rit != m_waveforms.rend();
         ++rit)
    {
        if (rit->second->GetBurstLengthInSymbols() == burstLength)
        {
            // The waveform more robust than previous one
            if (rit->second->GetPayloadInBytes() < payloadInBytes)
            {
                payloadInBytes = rit->second->GetPayloadInBytes();
                wfId = rit->first;
                found = true;
            }
        }
    }
 
    return found;
}
 
void
SatWaveformConf::Dump(double carrierBandwidthInHz, double symbolRateInBaud) const
{
    NS_LOG_FUNCTION(this << carrierBandwidthInHz << symbolRateInBaud);
 
    for (std::map<uint32_t, Ptr<SatWaveform>>::const_iterator it = m_waveforms.begin();
         it != m_waveforms.end();
         ++it)
    {
        std::cout << "WaveformId: " << it->first << " ";
        it->second->Dump(carrierBandwidthInHz, symbolRateInBaud);
    }
}
 
SatEnums::SatModcod_t
SatWaveformConf::GetModCod(uint32_t wfId) const
{
    NS_LOG_FUNCTION(this << wfId);
 
    if (m_minWfId > wfId || wfId > m_maxWfId)
    {
        NS_FATAL_ERROR("SatWaveformConf::GetModCod - unsupported waveform id: " << wfId);
    }
 
    std::map<uint32_t, Ptr<SatWaveform>>::const_iterator it = m_waveforms.find(wfId);
 
    if (it != m_waveforms.end())
    {
        return m_waveforms.at(wfId)->GetModCod();
    }
    else
    {
        NS_FATAL_ERROR("Waveform id: " << wfId << " not found in the waveform container!");
    }
 
    return SatEnums::SAT_NONVALID_MODCOD;
}
 
SatEnums::SatModcod_t
SatWaveformConf::ConvertToModCod(uint32_t modulatedBits,
                                 uint32_t codingRateNumerator,
                                 uint32_t codingRateDenominator) const
{
    NS_LOG_FUNCTION(this << modulatedBits << codingRateNumerator << codingRateDenominator);
 
    switch (modulatedBits)
    {
    // BPSK
    case 1: {
        if (codingRateNumerator == 1 && codingRateDenominator == 3)
        {
            return SatEnums::SAT_MODCOD_BPSK_1_TO_3;
        }
        else
        {
            NS_FATAL_ERROR("Unsupported coding rate numerator: "
                           << codingRateNumerator << ", denominator: " << codingRateDenominator);
        }
        break;
    }
    // QPSK
    case 2: {
        if (codingRateNumerator == 1 && codingRateDenominator == 3)
        {
            return SatEnums::SAT_MODCOD_QPSK_1_TO_3;
        }
        else if (codingRateNumerator == 1 && codingRateDenominator == 2)
        {
            return SatEnums::SAT_MODCOD_QPSK_1_TO_2;
        }
        else if (codingRateNumerator == 2 && codingRateDenominator == 3)
        {
            return SatEnums::SAT_MODCOD_QPSK_2_TO_3;
        }
        else if (codingRateNumerator == 3 && codingRateDenominator == 4)
        {
            return SatEnums::SAT_MODCOD_QPSK_3_TO_4;
        }
        else if (codingRateNumerator == 5 && codingRateDenominator == 6)
        {
            return SatEnums::SAT_MODCOD_QPSK_5_TO_6;
        }
        else
        {
            NS_FATAL_ERROR("Unsupported coding rate numerator: "
                           << codingRateNumerator << ", denominator: " << codingRateDenominator);
        }
        break;
    }
    // 8PSK
    case 3: {
        if (codingRateNumerator == 2 && codingRateDenominator == 3)
        {
            return SatEnums::SAT_MODCOD_8PSK_2_TO_3;
        }
        else if (codingRateNumerator == 3 && codingRateDenominator == 4)
        {
            return SatEnums::SAT_MODCOD_8PSK_3_TO_4;
        }
        else if (codingRateNumerator == 5 && codingRateDenominator == 6)
        {
            return SatEnums::SAT_MODCOD_8PSK_5_TO_6;
        }
        else
        {
            NS_FATAL_ERROR("Unsupported coding rate numerator: "
                           << codingRateNumerator << ", denominator: " << codingRateDenominator);
        }
        break;
    }
    // 16 QAM
    case 4: {
        if (codingRateNumerator == 3 && codingRateDenominator == 4)
        {
            return SatEnums::SAT_MODCOD_16QAM_3_TO_4;
        }
        else if (codingRateNumerator == 5 && codingRateDenominator == 6)
        {
            return SatEnums::SAT_MODCOD_16QAM_5_TO_6;
        }
        else
        {
            NS_FATAL_ERROR("Unsupported coding rate numerator: "
                           << codingRateNumerator << ", denominator: " << codingRateDenominator);
        }
 
        break;
    }
    default: {
        NS_FATAL_ERROR("Unsupported modulated bits:" << modulatedBits);
        break;
    }
    }
    return SatEnums::SAT_NONVALID_MODCOD;
}
 
} // namespace ns3