nr-eesm-ir.cc

// Copyright (c) 2020 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)
//
// SPDX-License-Identifier: GPL-2.0-only
 
#include "nr-eesm-ir.h"
 
#include "ns3/log.h"
 
namespace ns3
{
 
NS_LOG_COMPONENT_DEFINE("NrEesmIr");
NS_OBJECT_ENSURE_REGISTERED(NrEesmIr);
 
NrEesmIr::NrEesmIr()
{
    NS_LOG_FUNCTION(this);
}
 
NrEesmIr::~NrEesmIr()
{
    NS_LOG_FUNCTION(this);
}
 
TypeId
NrEesmIr::GetTypeId()
{
    static TypeId tid = TypeId("ns3::NrEesmIr").SetParent<NrEesmErrorModel>();
    return tid;
}
 
double
NrEesmIr::ComputeSINR(const SpectrumValue& sinr,
                      const std::vector<int>& map,
                      uint8_t mcs,
                      uint32_t sizeBit,
                      const NrErrorModel::NrErrorModelHistory& sinrHistory) const
{
    NS_LOG_FUNCTION(this);
    // HARQ INCREMENTAL REDUNDANCY: update SINReff and ECR after retx, assuming
    // no repetition of coded bits.
 
    // compute equivalent effective code rate after retransmissions and total map size
    uint32_t codeBitsSum = 0;
    uint32_t infoBits = DynamicCast<NrEesmErrorModelOutput>(sinrHistory.front())
                            ->m_infoBits; // information bits of the first TB
    double mapSumSize = 0.0;
 
    for (const Ptr<NrErrorModelOutput>& output : sinrHistory)
    {
        Ptr<NrEesmErrorModelOutput> sinrHistorytemp = DynamicCast<NrEesmErrorModelOutput>(output);
        NS_ASSERT(sinrHistorytemp != nullptr);
 
        NS_LOG_DEBUG(" Exponential SINR sum " << sinrHistorytemp->m_sinrExp << " codeBits "
                                              << sinrHistorytemp->m_codeBits
                                              << " infoBits: " << sinrHistorytemp->m_infoBits);
 
        codeBitsSum += sinrHistorytemp->m_codeBits;
        mapSumSize += sinrHistorytemp->m_map.size();
    }
    mapSumSize += map.size();
    codeBitsSum += sizeBit / GetMcsEcrTable()->at(mcs);
    ;
    const_cast<NrEesmIr*>(this)->m_Reff = infoBits / static_cast<double>(codeBitsSum);
 
    NS_LOG_INFO(" Reff " << m_Reff << " HARQ history (previous) " << sinrHistory.size());
 
    // compute effective SINR with expSINR_previousTx and mapSumSize
    double expSINR_previousTx = DynamicCast<NrEesmErrorModelOutput>(sinrHistory.back())->m_sinrExp;
    return SinrEff(sinr, map, mcs, expSINR_previousTx, mapSumSize);
}
 
double
NrEesmIr::GetMcsEq(uint8_t mcsTx) const
{
    NS_LOG_FUNCTION(this);
    // PHY abstraction for HARQ-IR retx -> get closest ECR to Reff from the
    // available ones that belong to the same modulation order
 
    uint8_t mcs_eq = mcsTx;
 
    uint8_t ModOrder = GetMcsMTable()->at(mcsTx);
 
    NS_LOG_INFO(" Modulation order: " << +ModOrder);
    NS_LOG_INFO(" Reff: " << m_Reff);
 
    for (uint8_t mcsindex = (mcsTx - 1); mcsindex != 255; mcsindex--)
    // search from MCS=mcs-1 to MCS=0. end at 255 to account for wrap around of uint
    {
        if ((GetMcsMTable()->at(mcsindex) == ModOrder) && (GetMcsEcrTable()->at(mcsindex) > m_Reff))
        {
            mcs_eq--;
        }
    }
 
    return mcs_eq;
}
 
} // namespace ns3