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GabrielcarvferGabrielcarvfer
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lte: (fixes #447) Skip CQI report on spectrum-model mismatch
During a handover the UE PHY is reconfigured to the target cell's EARFCN and bandwidth, which changes the spectrum model of the noise and interference PSDs. A downlink control reception associated with the previous configuration can complete after the reconfiguration, so the SpectrumValue division in LteUePhy::GenerateMixedCqiReport aborted on the spectrum-model equality assertion. Guard each division with a spectrum-model check: use the data interference denominator only when its model matches, fall back to the noise PSD, and otherwise skip the mixed CQI report for this subframe. Add a regression test (lte-handover-spectrum-model) that aborts before this change and runs to completion after.
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Lines changed: 275 additions & 2 deletions

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‎src/lte/CMakeLists.txt‎

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Original file line numberDiff line numberDiff line change
@@ -342,6 +342,7 @@ set(test_sources
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test/test-lte-epc-e2e-data.cc
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test/test-lte-handover-delay.cc
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test/test-lte-handover-failure.cc
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test/test-lte-handover-spectrum-model.cc
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test/test-lte-handover-target.cc
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test/test-lte-rlc-header.cc
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test/test-lte-rrc.cc

‎src/lte/model/lte-ue-phy.cc‎

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@@ -721,21 +721,36 @@ LteUePhy::GenerateMixedCqiReport(const SpectrumValue& sinr)
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m_ctrlSinrForRlf = sinr;
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SpectrumValue mixedSinr = (m_rsReceivedPower * m_paLinear);
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if (m_dataInterferencePowerUpdated)
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if (m_dataInterferencePowerUpdated &&
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mixedSinr.GetSpectrumModel() == m_dataInterferencePower.GetSpectrumModel())
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{
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// we have a measurement of interf + noise for the denominator
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// of SINR = S/(I+N)
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mixedSinr /= m_dataInterferencePower;
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m_dataInterferencePowerUpdated = false;
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NS_LOG_LOGIC("data interf measurement available, SINR = " << mixedSinr);
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}
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else
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else if (mixedSinr.GetSpectrumModel() == m_noisePsd->GetSpectrumModel())
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{
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// we did not see any interference on data, so interference is
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// there and we have only noise at the denominator of SINR
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mixedSinr /= (*m_noisePsd);
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NS_LOG_LOGIC("no data interf measurement available, SINR = " << mixedSinr);
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}
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else
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{
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// During a handover the UE PHY is reconfigured to the target cell's
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// EARFCN/bandwidth, which changes the spectrum model of m_noisePsd
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// (and m_dataInterferencePower). A control reception that started on
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// the previous cell can complete after this reconfiguration, leaving
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// m_rsReceivedPower on a different spectrum model than the denominator.
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// Dividing mismatched spectrum values would abort (@issueid{447}); the
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// resulting measurement is meaningless, so skip this CQI report.
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m_dataInterferencePowerUpdated = false;
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NS_LOG_LOGIC("spectrum model mismatch (handover reconfiguration), "
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"skipping mixed CQI report");
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return;
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}
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/*
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* some RBs are not used in PDSCH and their SINR is very high

‎src/lte/test/test-lte-handover-spectrum-model.cc‎

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/*
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* Copyright (c) 2026 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)
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*
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* SPDX-License-Identifier: GPL-2.0-only
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*
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* Author: Gabriel Ferreira <gabrielcarvfer@gmail.com>
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*/
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#include "ns3/application-container.h"
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#include "ns3/boolean.h"
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#include "ns3/config.h"
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#include "ns3/constant-velocity-mobility-model.h"
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#include "ns3/data-rate.h"
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#include "ns3/double.h"
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#include "ns3/epc-tft.h"
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#include "ns3/eps-bearer.h"
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#include "ns3/inet-socket-address.h"
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#include "ns3/internet-stack-helper.h"
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#include "ns3/ipv4-address-helper.h"
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#include "ns3/ipv4-interface-container.h"
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#include "ns3/ipv4-static-routing-helper.h"
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#include "ns3/ipv4-static-routing.h"
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#include "ns3/lte-helper.h"
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#include "ns3/mobility-helper.h"
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#include "ns3/net-device-container.h"
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#include "ns3/node-container.h"
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#include "ns3/nstime.h"
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#include "ns3/packet-sink-helper.h"
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#include "ns3/point-to-point-epc-helper.h"
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#include "ns3/point-to-point-helper.h"
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#include "ns3/position-allocator.h"
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#include "ns3/rng-seed-manager.h"
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#include "ns3/simulator.h"
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#include "ns3/test.h"
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#include "ns3/udp-client-server-helper.h"
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#include "ns3/uinteger.h"
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using namespace ns3;
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NS_LOG_COMPONENT_DEFINE("LteHandoverSpectrumModelTest");
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/**
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* @ingroup lte-test
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*
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* @brief Regression test for @issueid{447}: a UE handing over between cells must
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* not abort with the spectrum-model mismatch assertion
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* (m_spectrumModel == x.m_spectrumModel) in SpectrumValue.
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*
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* During a handover the UE PHY is reconfigured to the target cell, which
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* changes the spectrum model of its noise/interference PSDs. A downlink
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* control reception associated with the previous configuration can complete
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* after the reconfiguration, so LteUePhy::GenerateMixedCqiReport() must not
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* divide two SpectrumValue objects with different spectrum models.
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*
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* The test runs a compact mobile multi-UE A3-RSRP handover scenario with the
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* control and data error models enabled (which trigger the handover/RLF
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* activity that exposes the race) and verifies that the simulation runs to
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* completion.
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*/
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class LteHandoverSpectrumModelTestCase : public TestCase
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{
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public:
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LteHandoverSpectrumModelTestCase();
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~LteHandoverSpectrumModelTestCase() override;
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private:
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void DoRun() override;
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};
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LteHandoverSpectrumModelTestCase::LteHandoverSpectrumModelTestCase()
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: TestCase("Handover does not abort on spectrum-model mismatch (issue #447)")
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{
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}
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LteHandoverSpectrumModelTestCase::~LteHandoverSpectrumModelTestCase()
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{
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}
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void
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LteHandoverSpectrumModelTestCase::DoRun()
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{
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// Deterministic run.
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RngSeedManager::SetSeed(1);
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RngSeedManager::SetRun(1);
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const double simTime = 5.0; // the pre-fix abort occurs at ~2.4 s
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const uint16_t numberOfUes = 30;
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const uint16_t numberOfCells = 5;
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const double speed = 16.0;
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Config::SetDefault("ns3::LteRlcUm::MaxTxBufferSize", UintegerValue(60 * 1024));
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Config::SetDefault("ns3::LteHelper::UseIdealRrc", BooleanValue(false));
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Config::SetDefault("ns3::LteSpectrumPhy::CtrlErrorModelEnabled", BooleanValue(true));
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Config::SetDefault("ns3::LteSpectrumPhy::DataErrorModelEnabled", BooleanValue(true));
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// Radio link failure timers.
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Config::SetDefault("ns3::LteUeRrc::N310", UintegerValue(1));
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Config::SetDefault("ns3::LteUeRrc::N311", UintegerValue(1));
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Config::SetDefault("ns3::LteUeRrc::T310", TimeValue(Seconds(1)));
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Ptr<LteHelper> lteHelper = CreateObject<LteHelper>();
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Ptr<PointToPointEpcHelper> epcHelper = CreateObject<PointToPointEpcHelper>();
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lteHelper->SetEpcHelper(epcHelper);
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lteHelper->SetPathlossModelType(TypeId::LookupByName("ns3::LogDistancePropagationLossModel"));
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lteHelper->SetSchedulerType("ns3::PfFfMacScheduler");
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lteHelper->SetHandoverAlgorithmType("ns3::A3RsrpHandoverAlgorithm");
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lteHelper->SetHandoverAlgorithmAttribute("Hysteresis", DoubleValue(3.0));
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lteHelper->SetHandoverAlgorithmAttribute("TimeToTrigger", TimeValue(MilliSeconds(256)));
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// Internet / remote host.
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Ptr<Node> pgw = epcHelper->GetPgwNode();
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NodeContainer remoteHostContainer;
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remoteHostContainer.Create(1);
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Ptr<Node> remoteHost = remoteHostContainer.Get(0);
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InternetStackHelper internet;
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internet.Install(remoteHostContainer);
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PointToPointHelper p2ph;
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p2ph.SetDeviceAttribute("DataRate", DataRateValue(DataRate("100Gb/s")));
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p2ph.SetDeviceAttribute("Mtu", UintegerValue(1500));
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p2ph.SetChannelAttribute("Delay", TimeValue(Seconds(0.010)));
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NetDeviceContainer internetDevices = p2ph.Install(pgw, remoteHost);
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Ipv4AddressHelper ipv4h;
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ipv4h.SetBase("1.0.0.0", "255.0.0.0");
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Ipv4InterfaceContainer internetIpIfaces = ipv4h.Assign(internetDevices);
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Ipv4Address remoteHostAddr = internetIpIfaces.GetAddress(1);
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Ipv4StaticRoutingHelper ipv4RoutingHelper;
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Ptr<Ipv4StaticRouting> remoteHostStaticRouting =
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ipv4RoutingHelper.GetStaticRouting(remoteHost->GetObject<Ipv4>());
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remoteHostStaticRouting->AddNetworkRouteTo(Ipv4Address("7.0.0.0"), Ipv4Mask("255.0.0.0"), 1);
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// eNodeBs: one macro plus several small cells along a line.
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NodeContainer enbNodes;
132+
enbNodes.Create(numberOfCells);
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Ptr<ListPositionAllocator> enbPosition = CreateObject<ListPositionAllocator>();
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enbPosition->Add(Vector(500, 0, 0)); // macro
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enbPosition->Add(Vector(10, 0, 0));
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enbPosition->Add(Vector(30, 0, 0));
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enbPosition->Add(Vector(50, 0, 0));
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enbPosition->Add(Vector(70, 0, 0));
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MobilityHelper enbMobility;
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enbMobility.SetMobilityModel("ns3::ConstantPositionMobilityModel");
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enbMobility.SetPositionAllocator(enbPosition);
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enbMobility.Install(enbNodes);
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NetDeviceContainer enbDevs;
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Config::SetDefault("ns3::LteEnbPhy::TxPower", DoubleValue(43.0));
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enbDevs.Add(lteHelper->InstallEnbDevice(enbNodes.Get(0)));
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Config::SetDefault("ns3::LteEnbPhy::TxPower", DoubleValue(20.0));
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for (uint16_t j = 1; j < numberOfCells; j++)
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{
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enbDevs.Add(lteHelper->InstallEnbDevice(enbNodes.Get(j)));
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}
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// UEs moving along the line of small cells.
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NodeContainer ueNodes;
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ueNodes.Create(numberOfUes);
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MobilityHelper ueMobility;
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ueMobility.SetMobilityModel("ns3::ConstantVelocityMobilityModel");
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ueMobility.Install(ueNodes);
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for (uint16_t i = 0; i < numberOfUes; i++)
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{
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ueNodes.Get(i)->GetObject<MobilityModel>()->SetPosition(Vector(0, 0, 0));
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ueNodes.Get(i)->GetObject<ConstantVelocityMobilityModel>()->SetVelocity(
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Vector(speed, 0, 0));
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}
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NetDeviceContainer ueDevs = lteHelper->InstallUeDevice(ueNodes);
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internet.Install(ueNodes);
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Ipv4InterfaceContainer ueIpIfaces = epcHelper->AssignUeIpv4Address(NetDeviceContainer(ueDevs));
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for (uint16_t i = 0; i < numberOfUes; i++)
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{
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lteHelper->Attach(ueDevs.Get(i));
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}
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// Downlink/uplink traffic and a dedicated bearer per UE. The scenario
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// mirrors the reporter's repro (sinks at both ends, a short packet
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// interval) which exposes the handover activity that triggers the bug.
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Ptr<UniformRandomVariable> startTime = CreateObject<UniformRandomVariable>();
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startTime->SetAttribute("Min", DoubleValue(0));
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startTime->SetAttribute("Max", DoubleValue(0.010));
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uint16_t dlPort = 10000;
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uint16_t ulPort = 20000;
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for (uint16_t u = 0; u < numberOfUes; ++u)
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{
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Ptr<Node> ue = ueNodes.Get(u);
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Ptr<Ipv4StaticRouting> ueStaticRouting =
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ipv4RoutingHelper.GetStaticRouting(ue->GetObject<Ipv4>());
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ueStaticRouting->SetDefaultRoute(epcHelper->GetUeDefaultGatewayAddress(), 1);
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++dlPort;
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++ulPort;
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UdpClientHelper dlClientHelper(ueIpIfaces.GetAddress(u), dlPort);
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dlClientHelper.SetAttribute("Interval", TimeValue(MilliSeconds(1)));
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dlClientHelper.SetAttribute("MaxPackets", UintegerValue(1000000));
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ApplicationContainer dlApps = dlClientHelper.Install(remoteHost);
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PacketSinkHelper dlSink("ns3::UdpSocketFactory",
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InetSocketAddress(Ipv4Address::GetAny(), dlPort));
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dlApps.Add(dlSink.Install(ue));
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UdpClientHelper ulClientHelper(remoteHostAddr, ulPort);
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ulClientHelper.SetAttribute("Interval", TimeValue(MilliSeconds(1)));
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ulClientHelper.SetAttribute("MaxPackets", UintegerValue(1000000));
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ApplicationContainer ulApps = ulClientHelper.Install(ue);
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PacketSinkHelper ulSink("ns3::UdpSocketFactory",
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InetSocketAddress(Ipv4Address::GetAny(), ulPort));
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ulApps.Add(ulSink.Install(remoteHost));
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Ptr<EpcTft> tft = Create<EpcTft>();
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EpcTft::PacketFilter dlpf;
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dlpf.localPortStart = dlPort;
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dlpf.localPortEnd = dlPort;
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tft->Add(dlpf);
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EpcTft::PacketFilter ulpf;
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ulpf.remotePortStart = ulPort;
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ulpf.remotePortEnd = ulPort;
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tft->Add(ulpf);
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EpsBearer bearer(EpsBearer::NGBR_IMS);
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lteHelper->ActivateDedicatedEpsBearer(ueDevs.Get(u), bearer, tft);
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Time appStart = Seconds(startTime->GetValue());
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dlApps.Start(appStart);
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ulApps.Start(appStart);
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}
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lteHelper->AddX2Interface(enbNodes);
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Simulator::Stop(Seconds(simTime));
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Simulator::Run();
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// Reaching this point means the simulation completed without the
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// spectrum-model mismatch assertion aborting it (@issueid{447}).
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NS_TEST_ASSERT_MSG_EQ(Simulator::Now().GetSeconds() >= simTime - 1e-6,
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true,
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"Simulation did not run to completion");
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Simulator::Destroy();
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}
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/**
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* @ingroup lte-test
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*
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* @brief Test suite for the handover spectrum-model regression test.
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*/
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class LteHandoverSpectrumModelTestSuite : public TestSuite
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{
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public:
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LteHandoverSpectrumModelTestSuite();
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};
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LteHandoverSpectrumModelTestSuite::LteHandoverSpectrumModelTestSuite()
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: TestSuite("lte-handover-spectrum-model", Type::SYSTEM)
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{
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AddTestCase(new LteHandoverSpectrumModelTestCase(), TestCase::Duration::EXTENSIVE);
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}
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/// Static variable for test initialization
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static LteHandoverSpectrumModelTestSuite g_lteHandoverSpectrumModelTestSuite;

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