satellite-phy-rx-carrier-per-slot.cc

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014 Magister Solutions Ltd.
 * Copyright (c) 2018 CNES
 *
 * 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: Jani Puttonen <jani.puttonen@magister.fi>
 * Author: Mathias Ettinger <mettinger@toulouse.viveris.fr>
 */
 
#include "satellite-phy-rx-carrier-per-slot.h"
 
#include "satellite-uplink-info-tag.h"
 
#include "ns3/address.h"
#include "ns3/boolean.h"
#include "ns3/log.h"
#include "ns3/simulator.h"
 
#include <algorithm>
#include <deque>
#include <limits>
#include <ostream>
#include <utility>
 
NS_LOG_COMPONENT_DEFINE("SatPhyRxCarrierPerSlot");
 
namespace ns3
{
 
NS_OBJECT_ENSURE_REGISTERED(SatPhyRxCarrierPerSlot);
 
SatPhyRxCarrierPerSlot::SatPhyRxCarrierPerSlot(uint32_t carrierId,
                                               Ptr<SatPhyRxCarrierConf> carrierConf,
                                               Ptr<SatWaveformConf> waveformConf,
                                               bool randomAccessEnabled)
    : SatPhyRxCarrier(carrierId, carrierConf, waveformConf, randomAccessEnabled),
      m_randomAccessBitsInFrame(0),
      m_randomAccessAllocationChannelId(0),
      m_randomAccessCollisionModel(SatPhyRxCarrierConf::RA_COLLISION_NOT_DEFINED),
      m_randomAccessConstantErrorRate(0.0),
      m_randomAccessAverageNormalizedOfferedLoadMeasurementWindowSize(0),
      m_enableRandomAccessDynamicLoadControl(false),
      m_disableErrorHighTransmissionTime(false)
{
    if (randomAccessEnabled)
    {
        m_randomAccessCollisionModel = carrierConf->GetRandomAccessCollisionModel();
        m_randomAccessConstantErrorRate = carrierConf->GetRandomAccessConstantErrorRate();
        m_randomAccessAverageNormalizedOfferedLoadMeasurementWindowSize =
            carrierConf->GetRandomAccessAverageNormalizedOfferedLoadMeasurementWindowSize();
        m_enableRandomAccessDynamicLoadControl =
            carrierConf->IsRandomAccessDynamicLoadControlEnabled();
 
        NS_LOG_INFO("RA interference model: "
                    << carrierConf->GetInterferenceModel(true)
                    << ", RA collision model: " << m_randomAccessCollisionModel
                    << ", RA avg. normalized offered load measurement window size: "
                    << m_randomAccessAverageNormalizedOfferedLoadMeasurementWindowSize);
    }
}
 
SatPhyRxCarrierPerSlot::~SatPhyRxCarrierPerSlot()
{
    NS_LOG_FUNCTION(this);
}
 
void
SatPhyRxCarrierPerSlot::BeginEndScheduling()
{
}
 
TypeId
SatPhyRxCarrierPerSlot::GetTypeId(void)
{
    static TypeId tid =
        TypeId("ns3::SatPhyRxCarrierPerSlot")
            .SetParent<SatPhyRxCarrier>()
            .AddAttribute(
                "DisableErrorHighTransmissionTime",
                "Disable fatal error when transmission time is higher than propagation time, but "
                "computations are less precise.",
                BooleanValue(false),
                MakeBooleanAccessor(&SatPhyRxCarrierPerSlot::m_disableErrorHighTransmissionTime),
                MakeBooleanChecker())
            .AddTraceSource(
                "SlottedAlohaRxCollision",
                "Received a packet burst through Random Access Slotted ALOHA",
                MakeTraceSourceAccessor(&SatPhyRxCarrierPerSlot::m_slottedAlohaRxCollisionTrace),
                "ns3::SatPhyRxCarrierPacketProbe::RxStatusCallback")
            .AddTraceSource(
                "SlottedAlohaRxError",
                "Received a packet burst through Random Access Slotted ALOHA",
                MakeTraceSourceAccessor(&SatPhyRxCarrierPerSlot::m_slottedAlohaRxErrorTrace),
                "ns3::SatPhyRxCarrierPacketProbe::RxStatusCallback");
    return tid;
}
 
void
SatPhyRxCarrierPerSlot::DoDispose()
{
    NS_LOG_FUNCTION(this);
 
    SatPhyRxCarrier::DoDispose();
    m_randomAccessDynamicLoadControlNormalizedOfferedLoad.clear();
}
 
Ptr<SatInterference::InterferenceChangeEvent>
SatPhyRxCarrierPerSlot::CreateInterference(Ptr<SatSignalParameters> rxParams, Address senderAddress)
{
    NS_LOG_FUNCTION(this << rxParams << senderAddress);
 
    // Case satellite regenerative
    if (GetLinkRegenerationMode() != SatEnums::TRANSPARENT)
    {
        return GetInterferenceModel()->Add(rxParams->m_duration,
                                           rxParams->m_rxPower_W,
                                           GetOwnAddress());
    }
 
    SatEnums::ChannelType_t ct = GetChannelType();
    if (ct == SatEnums::RETURN_FEEDER_CH)
    {
        // In feeder downlink the interference by UTs in the same
        // beam (intra-beam interference e.g. due to random access) SHOULD NOT be tracked.
        // Intra-beam interference is already taken into account at the satellite. Thus,
        // here we pass intra-beam transmissions with zero interference power to the
        // interference model.
        // Rx power in the rxParams is the received power of only one of the interfering
        // signals of the wanted signal. In reality, we are receiving the same signal
        // through all the co-channel transponders of the satellite, where the rxPower
        // is the C and all the other components are considered as interference I.
        // This can be compensated with the following equation:
        // rxPower = rxParams->m_rxPower_W * (1 + 1/rxParams->m_sinr);
        // See more from satellite module documentation.
 
        double rxPower(0.0);
 
        if (rxParams->m_beamId != GetBeamId())
        {
            if (!rxParams->HasSinrComputed())
            {
                if (m_disableErrorHighTransmissionTime)
                {
                    NS_LOG_WARN("SatPhyRx::StartRx - too long transmission time: packet started to "
                                "be received in a ground entity while not being fully received on "
                                "the satellite: interferences could not be properly computed.");
                    rxPower = rxParams->m_rxPower_W;
                }
                else
                {
                    NS_FATAL_ERROR(
                        "SatPhyRx::StartRx - too long transmission time: packet started to be "
                        "received in a ground entity while not being fully received on the "
                        "satellite: interferences could not be properly computed.");
                }
            }
            else
            {
                rxPower = rxParams->m_rxPower_W * (1 + 1 / rxParams->GetSinr());
            }
        }
 
        // Add the interference even regardless.
        return GetInterferenceModel()->Add(rxParams->m_duration, rxPower, GetOwnAddress());
    }
    else if (ct == SatEnums::FORWARD_USER_CH)
    {
        return GetInterferenceModel()->Add(rxParams->m_duration,
                                           rxParams->m_rxPower_W,
                                           GetOwnAddress());
    }
 
    NS_FATAL_ERROR("SatSatellitePhyRxCarrier::CreateInterference - Invalid channel type!");
    return nullptr;
}
 
void
SatPhyRxCarrierPerSlot::EndRxData(uint32_t key)
{
    NS_LOG_FUNCTION(this << key);
 
    NS_LOG_INFO(this << " state: " << GetState());
 
    NS_ASSERT(GetState() == RX);
 
    rxParams_s packetRxParams = GetStoredRxParams(key);
 
    const uint32_t nPackets = packetRxParams.rxParams->m_packetsInBurst.size();
 
    DecreaseNumOfRxState(packetRxParams.rxParams->m_txInfo.packetType);
 
    // Test if when receiving a packet on ground from transparent satellite, uplink SINR has been
    // correctly set
    if (GetLinkRegenerationMode() == SatEnums::TRANSPARENT)
    {
        NS_ASSERT(packetRxParams.rxParams->HasSinrComputed());
    }
 
    packetRxParams.rxParams->SetInterferencePower(
        GetInterferenceModel()->Calculate(packetRxParams.interferenceEvent));
 
    ReceiveSlot(packetRxParams, nPackets);
 
    GetInterferenceModel()->NotifyRxEnd(packetRxParams.interferenceEvent);

    packetRxParams.interferenceEvent = nullptr;
    RemoveStoredRxParams(key);
}
 
bool
SatPhyRxCarrierPerSlot::ProcessSlottedAlohaCollisions(
    double cSinr,
    Ptr<SatSignalParameters> rxParams,
    Ptr<SatInterference::InterferenceChangeEvent> interferenceEvent)
{
    NS_LOG_FUNCTION(this);
 
    bool phyError = false;
 
    if (m_randomAccessCollisionModel ==
        SatPhyRxCarrierConf::RA_COLLISION_ALWAYS_DROP_ALL_COLLIDING_PACKETS)
    {
        phyError = GetInterferenceModel()->HasCollision(interferenceEvent);
        NS_LOG_INFO("Strict collision mode, phyError: " << phyError);
    }
    else if (m_randomAccessCollisionModel == SatPhyRxCarrierConf::RA_COLLISION_CHECK_AGAINST_SINR)
    {
        phyError = CheckAgainstLinkResults(cSinr, rxParams);
        NS_LOG_INFO("Composite SINR mode, phyError: " << phyError);
    }
    else if (m_randomAccessCollisionModel == SatPhyRxCarrierConf::RA_CONSTANT_COLLISION_PROBABILITY)
    {
        double r = GetUniformRandomValue(0, 1);
        if (r < m_randomAccessConstantErrorRate)
        {
            phyError = true;
        }
        NS_LOG_INFO("Constant collision probability mode, phyError: " << phyError);
    }
    else
    {
        NS_FATAL_ERROR("SatPhyRxCarrier::ProcessSlottedAlohaCollisions - Random access collision "
                       "model not defined");
    }
 
    return phyError;
}
 
void
SatPhyRxCarrierPerSlot::ReceiveSlot(SatPhyRxCarrier::rxParams_s packetRxParams,
                                    const uint32_t nPackets)
{
    NS_LOG_FUNCTION(this << &packetRxParams << nPackets);
 
    NS_ASSERT(packetRxParams.rxParams->m_txInfo.packetType != SatEnums::PACKET_TYPE_CRDSA);
    double sinr = CalculateSinr(packetRxParams.rxParams->m_rxPower_W,
                                packetRxParams.rxParams->GetInterferencePower(),
                                m_rxNoisePowerW,
                                m_rxAciIfPowerW,
                                m_rxExtNoisePowerW,
                                m_additionalInterferenceCallback());
 
    SatAddressE2ETag addressE2ETag;
    packetRxParams.rxParams->m_packetsInBurst[0]->PeekPacketTag(addressE2ETag);
 
    // Update link specific SINR trace
    switch (GetChannelType())
    {
    case SatEnums::RETURN_USER_CH:
    case SatEnums::RETURN_FEEDER_CH:
        m_linkSinrTrace(SatUtils::LinearToDb(sinr), addressE2ETag.GetE2ESourceAddress());
        break;
    case SatEnums::FORWARD_USER_CH:
    case SatEnums::FORWARD_FEEDER_CH:
        m_linkSinrTrace(SatUtils::LinearToDb(sinr), addressE2ETag.GetE2EDestAddress());
        break;
    default:
        NS_FATAL_ERROR("Incorrect channel for satPhyRxCarrierPerSlot: "
                       << SatEnums::GetChannelTypeName(GetChannelType()));
    }

    bool phyError(false);

    double cSinr;
    switch (GetLinkRegenerationMode())
    {
    case SatEnums::TRANSPARENT:
        cSinr = CalculateCompositeSinr(sinr, packetRxParams.rxParams->GetSinr());
        break;
    case SatEnums::REGENERATION_PHY:
    case SatEnums::REGENERATION_LINK:
    case SatEnums::REGENERATION_NETWORK:
        cSinr = sinr;
        break;
    default:
        NS_FATAL_ERROR("Incorrect regeneration mode for satPhyRxCarrierPerSlot");
    }
 
    if (!m_cnoCallback.IsNull())
    {
        switch (GetLinkRegenerationMode())
        {
        case SatEnums::TRANSPARENT:
        case SatEnums::REGENERATION_PHY: {
            double worstSinr = GetWorstSinr(sinr, packetRxParams.rxParams->GetSinr());

            double cno = (GetLinkRegenerationMode() == SatEnums::TRANSPARENT) ? cSinr : worstSinr;
 
            // Forward link
            switch (GetNodeInfo()->GetNodeType())
            {
            case SatEnums::NT_UT:
                cno = SatUtils::DbToLinear(
                    GetChannelEstimationErrorContainer()->AddError(SatUtils::LinearToDb(cno)));
                break;
            case SatEnums::NT_GW:
                cno = SatUtils::DbToLinear(GetChannelEstimationErrorContainer()->AddError(
                    SatUtils::LinearToDb(cno),
                    packetRxParams.rxParams->m_txInfo.waveformId));
                break;
            default:
                NS_FATAL_ERROR("Unsupported node type for a NORMAL Rx model!");
            }
 
            cno *= m_rxBandwidthHz;
 
            packetRxParams.rxParams->m_packetsInBurst[0]->PeekPacketTag(addressE2ETag);
 
            m_cnoCallback(packetRxParams.rxParams->m_satId,
                          packetRxParams.rxParams->m_beamId,
                          addressE2ETag.GetE2ESourceAddress(),
                          GetOwnAddress(),
                          cno,
                          false);
            break;
        }
        case SatEnums::REGENERATION_LINK:
        case SatEnums::REGENERATION_NETWORK: {
            SatSignalParameters::PacketsInBurst_t packets =
                packetRxParams.rxParams->m_packetsInBurst;
            SatSignalParameters::PacketsInBurst_t::const_iterator i;
            for (i = packets.begin(); i != packets.end(); i++)
            {
                SatUplinkInfoTag satUplinkInfoTag;
                if (!(*i)->PeekPacketTag(satUplinkInfoTag))
                {
                    NS_FATAL_ERROR("SatUplinkInfoTag not found !");
                }

                double worstCno = GetWorstSinr(sinr, satUplinkInfoTag.GetSinr());
                double downlinkCno = sinr;
 
                // Forward link and return link use same algorithms (because of SCPC)
                switch (GetNodeInfo()->GetNodeType())
                {
                case SatEnums::NT_UT:
                case SatEnums::NT_GW:
                    worstCno = SatUtils::DbToLinear(GetChannelEstimationErrorContainer()->AddError(
                        SatUtils::LinearToDb(worstCno)));
                    downlinkCno =
                        SatUtils::DbToLinear(GetChannelEstimationErrorContainer()->AddError(
                            SatUtils::LinearToDb(downlinkCno)));
                    break;
                default:
                    NS_FATAL_ERROR("Unsupported node type for a NORMAL Rx model!");
                }
 
                worstCno *= m_rxBandwidthHz;
                downlinkCno *= m_rxBandwidthHz;
 
                (*i)->PeekPacketTag(addressE2ETag);
 
                SatMacTag satMacTag;
                (*i)->PeekPacketTag(satMacTag);
 
                m_cnoCallback(satUplinkInfoTag.GetSatId(),
                              satUplinkInfoTag.GetBeamId(),
                              addressE2ETag.GetE2ESourceAddress(),
                              GetOwnAddress(),
                              worstCno,
                              false);
 
                m_cnoCallback(GetSatId(),
                              GetBeamId(),
                              satMacTag.GetSourceAddress(),
                              GetOwnAddress(),
                              downlinkCno,
                              true);
            }
            break;
        }
        default:
            NS_FATAL_ERROR("Incorrect regeneration mode for SatPhyRxCarrierPerSlot");
        }
    }
 
    // Update composite SINR trace for DAMA and Slotted ALOHA packets
    m_sinrTrace(SatUtils::LinearToDb(cSinr), packetRxParams.sourceAddress);

    if (IsCompositeSinrOutputTraceEnabled())
    {
        DoCompositeSinrOutputTrace(cSinr);
    }
 
    if (packetRxParams.rxParams->m_txInfo.packetType == SatEnums::PACKET_TYPE_SLOTTED_ALOHA)
    {
        NS_LOG_INFO("Slotted ALOHA packet received");
 
        // Update the load with FEC block size!
        m_randomAccessBitsInFrame += packetRxParams.rxParams->m_txInfo.fecBlockSizeInBytes *
                                     SatConstVariables::BITS_PER_BYTE;

        phyError = ProcessSlottedAlohaCollisions(cSinr,
                                                 packetRxParams.rxParams,
                                                 packetRxParams.interferenceEvent);
 
        if (nPackets > 0)
        {
            const bool hasCollision =
                GetInterferenceModel()->HasCollision(packetRxParams.interferenceEvent);
            m_slottedAlohaRxCollisionTrace(nPackets,                     // number of packets
                                           packetRxParams.sourceAddress, // sender address
                                           hasCollision                  // collision flag
            );
            m_slottedAlohaRxErrorTrace(nPackets,                     // number of packets
                                       packetRxParams.sourceAddress, // sender address
                                       phyError                      // error flag
            );
        }
    }
    else
    {
        phyError = CheckAgainstLinkResults(cSinr, packetRxParams.rxParams);
 
        if (nPackets > 0)
        {
            switch (GetChannelType())
            {
            case SatEnums::FORWARD_FEEDER_CH:
            case SatEnums::FORWARD_USER_CH:
                m_daRxTrace(nPackets,                   // number of packets
                            packetRxParams.destAddress, // destination address
                            phyError                    // error flag
                );
                break;
            case SatEnums::RETURN_FEEDER_CH:
            case SatEnums::RETURN_USER_CH:
                m_daRxTrace(nPackets,                     // number of packets
                            packetRxParams.sourceAddress, // destination address
                            phyError                      // error flag
                );
                break;
            default:
                NS_FATAL_ERROR("Channel unknown !");
            }
        }
 
        m_daRxCarrierIdTrace(GetCarrierId(), packetRxParams.sourceAddress);
    }
 
    switch (GetLinkRegenerationMode())
    {
    case SatEnums::TRANSPARENT:
    case SatEnums::REGENERATION_PHY:
        packetRxParams.rxParams->SetSinr(sinr, m_additionalInterferenceCallback());
        break;
    case SatEnums::REGENERATION_LINK:
    case SatEnums::REGENERATION_NETWORK: {
        SatSignalParameters::PacketsInBurst_t packets = packetRxParams.rxParams->m_packetsInBurst;
        SatSignalParameters::PacketsInBurst_t::const_iterator i;
        for (i = packets.begin(); i != packets.end(); i++)
        {
            SatUplinkInfoTag satUplinkInfoTag;
            (*i)->RemovePacketTag(satUplinkInfoTag);
            satUplinkInfoTag.SetSinr(sinr, m_additionalInterferenceCallback());
            (*i)->AddPacketTag(satUplinkInfoTag);
        }
        break;
    }
    default:
        NS_FATAL_ERROR("Incorrect regeneration mode for SatPhyRxCarrierPerSlot");
    }

    m_linkBudgetTrace(packetRxParams.rxParams,
                      GetOwnAddress(),
                      packetRxParams.destAddress,
                      packetRxParams.rxParams->GetInterferencePower(),
                      cSinr);

    m_rxCallback(packetRxParams.rxParams, phyError);
 
    packetRxParams.rxParams = nullptr;
}
 
void
SatPhyRxCarrierPerSlot::SaveMeasuredRandomAccessLoad(double measuredRandomAccessLoad)
{
    NS_LOG_FUNCTION(this);
 
    m_randomAccessDynamicLoadControlNormalizedOfferedLoad.push_back(measuredRandomAccessLoad);
 
    while (m_randomAccessDynamicLoadControlNormalizedOfferedLoad.size() >
           m_randomAccessAverageNormalizedOfferedLoadMeasurementWindowSize)
    {
        m_randomAccessDynamicLoadControlNormalizedOfferedLoad.pop_front();
    }
}
 
double
SatPhyRxCarrierPerSlot::CalculateAverageNormalizedOfferedRandomAccessLoad()
{
    NS_LOG_FUNCTION(this);
 
    double sum = 0.0;
    double averageNormalizedOfferedLoad = 0.0;
    std::deque<double>::iterator it;
 
    for (it = m_randomAccessDynamicLoadControlNormalizedOfferedLoad.begin();
         it != m_randomAccessDynamicLoadControlNormalizedOfferedLoad.end();
         it++)
    {
        sum += (*it);
    }
 
    if (!m_randomAccessDynamicLoadControlNormalizedOfferedLoad.empty())
    {
        averageNormalizedOfferedLoad =
            sum / m_randomAccessDynamicLoadControlNormalizedOfferedLoad.size();
    }
 
    NS_LOG_INFO("Average normalized offered load: " << averageNormalizedOfferedLoad);
 
    return averageNormalizedOfferedLoad;
}
 
} // namespace ns3