Resolving grantId = 0 Issue in Simu5G While Testing UE and gNodeB Application Interaction #1262

Wynn-TH · 2024-11-12T17:42:00Z

Wynn-TH
Nov 12, 2024

Hello everyone,

I am working with Simu5G on the OMNeT++ simulation platform, where I aim to test interactions between a User Equipment (UE) and a gNodeB at the application level, with data passing from the UE's MAC layer to the gNodeB's MEC layer. However, I am encountering an issue related to grantId being set to 0, which seems to disrupt communication between the UE and the gNodeB.

Problem Description:

During my tests, I observed that some grantId values sent by the UE are correctly set, but at other times they are 0. When the grantId is 0, the gNodeB reports the following error:<!> NRPacketFlowManagerGnb::ulMacPduArrived - grant [0] for nodeId [2059] not present -- in module (NRMacGnb) MultiMec_v3.gNodeB35.cellularNic.mac (id=3534), at t=1.816s, event #298902
This error suggests that the gNodeB cannot find a corresponding scheduling grant for grantId 0, leading to a failure in forwarding data from the UE, ultimately affecting the application-level interaction between the UE and gNodeB.

What I Have Tried So Far:

Ensured that the data packet includes the correct Cell ID to identify the target gNodeB.
Checked the UE's MAC layer code to verify that the grantId is properly set when creating data packets.
Observed that when the grantId is non-zero, communication between the UE and gNodeB proceeds as expected without errors.

Relevant Code Snippets:

Here is the code from the UE's MAC layer where I added some prints:

void LteMacUeD2D::macHandleGrant(cPacket* pktAux)
{
    EV << NOW << " LteMacUeD2D::macHandleGrant - UE [" << nodeId_ << "] - Grant received " << endl;

    // extract grant
    auto pkt = check_and_cast<inet::Packet*> (pktAux);
    auto grant = pkt->popAtFront<LteSchedulingGrant>();


    auto userInfo = pkt->getTag<UserControlInfo>();
    double carrierFrequency = userInfo->getCarrierFrequency();
    EV << NOW << " LteMacUeD2D::macHandleGrant - Direction: " << dirToA(grant->getDirection()) << " Carrier: " << carrierFrequency << endl;

    // delete old grant
    if (schedulingGrant_.find(carrierFrequency) != schedulingGrant_.end() && schedulingGrant_[carrierFrequency]!=nullptr)
    {
        schedulingGrant_[carrierFrequency] = nullptr;
    }

    // store received grant
    schedulingGrant_[carrierFrequency] = grant;
    std::cout << "### Grant ID: " << grant->getGrandId() << std::endl;
    if (grant->getPeriodic())
    {
        periodCounter_[carrierFrequency] = grant->getPeriod();
        expirationCounter_[carrierFrequency] = grant->getExpiration();
    }

    EV << NOW << "Node " << nodeId_ << " received grant of blocks " << grant->getTotalGrantedBlocks()
       << ", bytes " << grant->getGrantedCwBytes(0) <<" Direction: "<<dirToA(grant->getDirection()) << endl;

    // clearing pending RAC requests
    racRequested_=false;
    racD2DMulticastRequested_=false;

    if (userInfo != nullptr)
    {
        auto grantId = userInfo->getGrantId();

        std::cout << " LteMacUeD2D::macHandleGran UE received grant nodeId_ " << nodeId_
                  << " full path is " << getFullPath()
                  << " Grant ID: " << grantId << std::endl;
    }
    else
    {
        std::cout << "!!!LteMacUeD2D::macHandleGran UE received grant nodeId_ " << nodeId_
                  << " full path is " << getFullPath()
                  << " UserControlInfo not found." << std::endl;
    }
    delete pkt;
}

The sendLowerPackets method:

void LteMacUeD2D::sendLowerPackets(cPacket *pkt)
{
    auto packet = dynamic_cast<inet::Packet *>(pkt);
    if (packet == nullptr) {
        std::cerr << "LteMacUeD2D::sendLowerPackets - Packet is not of type inet::Packet" << std::endl;
        return;
    }

    auto userInfo = packet->findTag<UserControlInfo>();
    if (userInfo != nullptr)
    {
        auto grantId = userInfo->getGrantId();

        std::cout << "LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ " << nodeId_
                  << " full path is " << getFullPath()
                  << " Grant ID: " << grantId << std::endl;
    }
    else
    {
        std::cout << "!!!LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ " << nodeId_
                  << " full path is " << getFullPath()
                  << " UserControlInfo not found." << std::endl;
    }

    LteMacUe::sendLowerPackets(pkt);
}

The LteMacEnbD2D method:

void LteMacEnbD2D::macPduUnmake(cPacket* pktAux)
{
    auto pkt = check_and_cast<Packet *>(pktAux);
    auto macPkt = pkt->removeAtFront<LteMacPdu>();

    /*
     * @author Alessandro Noferi
     * Notify the pfm about the successful arrival of a TB from a UE.
     * From ETSI TS 138314 V16.0.0 (2020-07)
     *   tSucc: the point in time when the MAC SDU i was received successfully by the network
     */
    auto userInfo = pkt->getTag<UserControlInfo>();

    //tianhao
    auto grantId = userInfo->getGrantId();
    std::cout << " LteMacEnbD2D:macPduUnmake grant id " << userInfo->getGrantId() << std::endl;
    if(packetFlowManager_ == nullptr)
        std::cout << " ulMacPduArrived:packetFlowManager_ packetFlowManager_ is null " << std::endl;
    if (grantId == 0 && packetFlowManager_ != nullptr)
    {
        std::cout << "grantId is 0! " << std::endl;
        //throw cRuntimeError("grantId is 0!");
    }

    if(packetFlowManager_ != nullptr)
    {
        std::cout << " ulMacPduArrived:packetFlowManager_ grant id " << userInfo->getGrantId() << std::endl;
        packetFlowManager_->ulMacPduArrived(userInfo->getSourceId(), userInfo->getGrantId());
    }

    while (macPkt->hasSdu())
    {
        // Extract and send SDU
        auto upPkt = check_and_cast<Packet *>(macPkt->popSdu());
        take(upPkt);

        EV << "LteMacEnbD2D: pduUnmaker extracted SDU" << endl;

        // store descriptor for the incoming connection, if not already stored
        auto lteInfo = upPkt->getTag<FlowControlInfo>();
        MacNodeId senderId = lteInfo->getSourceId();
        LogicalCid lcid = lteInfo->getLcid();
        MacCid cid = idToMacCid(senderId, lcid);
        if (connDescIn_.find(cid) == connDescIn_.end())
        {
            FlowControlInfo toStore(*lteInfo);
            connDescIn_[cid] = toStore;
        }

        sendUpperPackets(upPkt);
    }

    while (macPkt->hasCe())
    {
        // Extract CE
        // TODO: vedere se   per cid o lcid
        MacBsr* bsr = check_and_cast<MacBsr*>(macPkt->popCe());
        auto lteInfo = pkt->getTag<UserControlInfo>();
        LogicalCid lcid = lteInfo->getLcid();  // one of SHORT_BSR or D2D_MULTI_SHORT_BSR

        MacCid cid = idToMacCid(lteInfo->getSourceId(), lcid); // this way, different connections from the same UE (e.g. one UL and one D2D)
                                                               // obtain different CIDs. With the inverse operation, you can get
                                                               // the LCID and discover if the connection is UL or D2D
        bufferizeBsr(bsr, cid);
    }
    pkt->insertAtFront(macPkt);

    delete pkt;
}

Part of the cout:

 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2055 full path is MultiMec_v3.ue[6].cellularNic.nrMac Grant ID: 69351
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2067 full path is MultiMec_v3.mmecHost[18].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 68469
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2055 full path is MultiMec_v3.ue[6].cellularNic.nrMac Grant ID: 69351
### Grant ID: 69506
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 69506
### Grant ID: 69508
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 69508
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2055 full path is MultiMec_v3.ue[6].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2058 full path is MultiMec_v3.ue[9].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2057 full path is MultiMec_v3.ue[8].cellularNic.nrMac Grant ID: 0
 LteMacEnbD2D:macPduUnmake grant id 68722
 ulMacPduArrived:packetFlowManager_ grant id 68722
 ulMacPduArrived:grant id 68722
 LteMacEnbD2D:macPduUnmake grant id 68724
 ulMacPduArrived:packetFlowManager_ grant id 68724
 ulMacPduArrived:grant id 68724
### Grant ID: 69614
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2067 full path is MultiMec_v3.mmecHost[18].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 69614
### Grant ID: 69620
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2057 full path is MultiMec_v3.ue[8].cellularNic.nrMac Grant ID: 69620
### Grant ID: 69624
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2055 full path is MultiMec_v3.ue[6].cellularNic.nrMac Grant ID: 69624
### Grant ID: 69630
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2058 full path is MultiMec_v3.ue[9].cellularNic.nrMac Grant ID: 69630
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2067 full path is MultiMec_v3.mmecHost[18].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 68718
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2058 full path is MultiMec_v3.ue[9].cellularNic.nrMac Grant ID: 69630
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2057 full path is MultiMec_v3.ue[8].cellularNic.nrMac Grant ID: 69620
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2055 full path is MultiMec_v3.ue[6].cellularNic.nrMac Grant ID: 69624
### Grant ID: 69733
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 69733
### Grant ID: 69735
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 69735
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2058 full path is MultiMec_v3.ue[9].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2057 full path is MultiMec_v3.ue[8].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 0
 LteMacEnbD2D:macPduUnmake grant id 67947
 ulMacPduArrived:packetFlowManager_ grant id 67947
 ulMacPduArrived:grant id 67947
### Grant ID: 69851
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2067 full path is MultiMec_v3.mmecHost[18].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 69851
### Grant ID: 69855
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2057 full path is MultiMec_v3.ue[8].cellularNic.nrMac Grant ID: 69855
### Grant ID: 69857
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2058 full path is MultiMec_v3.ue[9].cellularNic.nrMac Grant ID: 69857
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2067 full path is MultiMec_v3.mmecHost[18].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 69851
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2058 full path is MultiMec_v3.ue[9].cellularNic.nrMac Grant ID: 69857
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2057 full path is MultiMec_v3.ue[8].cellularNic.nrMac Grant ID: 69855
### Grant ID: 69863
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 69863
### Grant ID: 69865
 LteMacUeD2D::macHandleGran UE received grant nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 69865
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2067 full path is MultiMec_v3.mmecHost[18].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2058 full path is MultiMec_v3.ue[9].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2059 full path is MultiMec_v3.mmecHost[10].virtualisationInfrastructure.cellularNic.nrMac Grant ID: 0
LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2060 full path is MultiMec_v3.ue[11].cellularNic.nrMac Grant ID: 0
 LteMacEnbD2D:macPduUnmake grant id 68469
 ulMacPduArrived:packetFlowManager_ grant id 68469
 ulMacPduArrived:grant id 68469
 LteMacEnbD2D:macPduUnmake grant id 69351
 ulMacPduArrived:packetFlowManager_ grant id 69351
 ulMacPduArrived:grant id 69351
 LteMacEnbD2D:macPduUnmake grant id 0
grantId is 0! 
 ulMacPduArrived:packetFlowManager_ grant id 0
 ulMacPduArrived:grant id 0

The error's log:

** Event #298902  t=1.816  MultiMec_v3.gNodeB35.cellularNic.mac (NRMacGnb, id=3534)  on selfmsg ttiTick_ (omnetpp::cMessage, id=3295)

INFO: -----ENB MAIN LOOP -----
INFO: H-ARQ RX: feedback sent to TX process 0 Codeword  0of node with id 2059 result: ACK
INFO: 1.816LteMacBase::sendLowerPackets, Sending packet harqFeedback on port MAC_to_PHY
INFO: LteHarqBufferRx::extractCorrectPdus H-ARQ RX: pdu (id 165778 ) extracted from process 0to be sent upper
INFO: grantID: 0
INFO: it->grantID: 69506
INFO: grantID: 0
INFO: it->grantID: 69733
INFO: grantID: 0
INFO: it->grantID: 69863
<!> NRPacketFlowManagerGnb::ulMacPduArrived - grant [0] for nodeId [2059] not present -- in module (NRMacGnb) MultiMec_v3.gNodeB35.cellularNic.mac (id=3534), at t=1.816s, event #298902

Observations:

When the grantId is set to 0, some gNodeBs cannot find a corresponding scheduling grant, leading to communication failure (particularly in the last instance). However, many UEs have a grantId of 0 in the LteMacUeD2D::sendLowerPackets method, but their packets are not received by the gNodeB.
When the grantId is correctly set (non-zero), communication between the UE and gNodeB proceeds without issues, allowing data to be passed to the MEC layer.

Questions:

Is there an issue with the source parameter settings of the gNodeB that could be causing this problem?
Is there a potential issue with maintaining the schedulingGrant_ map in the UE's MAC layer?
Could there be situations where grants are being unintentionally cleared or not stored correctly?
Should I be marking packets or adding extra information to guarantee proper delivery?

Request for Assistance:

I find it difficult to understand why the problem does not appear when the first few grantIds are 0 (by the way, those packets are not received by the gNodeB), but only occurs when the last one is received by the gNodeB.

I understand that the grantId = 0 issue is leading to communication failures between the UE and gNodeB but I don't know how can I resolve it. I am looking for ways to ensure the grantId is correctly set and maintained. If anyone has experience with Simu5G and can provide insights on this matter, I would greatly appreciate your help.

giovanninardini · 2024-11-13T13:04:23Z

giovanninardini
Nov 13, 2024

Hello,

it might be a problem due to the grantId value not assigned when copying the SchedulingGrant object.
Please try to add the line grantId_ = other.grantId_; into the copy() function of class LteSchedulingGrant and see what happens.
This is just a guess, but it is worth a try.

1 reply

Wynn-TH Nov 14, 2024
Author

Hi Giovan, thank you for your suggestions and your contribution about the great simulation Simu5G.
I attempted the proposed changes, but unfortunately, the problem still persists. After checking the logs, I noticed something critical:
** Event #241601 t=1.504 MultiMec_v3.ue[6].cellularNic.nrMac (NRMacUe, id=8855) on selfmsg ttiTick_ (omnetpp::cMessage, id=54946)

INFO: ----- UE MAIN LOOP -----
INFO: 1.504NRMacUe::handleSelfMessage 2055 - HARQ process 5
INFO: 1.504 NRMacUe::handleSelfMessage 2055 entered scheduling
INFO: NRMacUe::handleSelfMessage - running LCG scheduler for carrier [2]
INFO: 1.504 LteSchedulerUeUl::schedule - Scheduling node 2055
INFO: 1.504 LteSchedulerUeUl::schedule - Node 2055 available data from grant are  blocks 1 [7 - Bytes]  on codeword 0
INFO: 1.504 LcgScheduler::schedule - Node  2055, Starting priority service for traffic class 0
INFO: 1.504 LcgScheduler::schedule - Node  2055, Starting priority service for traffic class 1
INFO: 1.504 LcgScheduler::schedule - Node  2055, Starting priority service for traffic class 2
INFO: 1.504 LcgScheduler::schedule - Node  2055, Starting priority service for traffic class 3
INFO: NRMacUe::handleSelfMessage - scheduled 0 connections on carrier 2
INFO: LteMacUeD2D::makeBsr() - BSR with size 50created
INFO: NRMacUe::macPduMake - BSR D2D created with size 50created
INFO: NRMacUe::macPduMake - [Used Acid=0]
INFO: NRMacUe: pduMaker created PDU: (2 B) (LteMacPdu)  containing 0 SDUs and 1 CEs with size 2
INFO: H-ARQ TX: new pdu (id 57252 ) inserted into process 0 codeword id: 0 for node with id 34
INFO: 1.504 NRMacUe::handleSelfMessage - incrementing counter for HARQ processes 5 --> 6
INFO: --- END UE MAIN LOOP ---
** Event #241664  t=1.504  MultiMec_v3.ue[6].cellularNic.nrMac (NRMacUe, id=8855)  on selfmsg flushHarqMsg (omnetpp::cMessage, id=136804)

INFO: LteHarqUnitTx::extractPdu - ndi set to true
INFO: LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2055 full path is MultiMec_v3.ue[6].cellularNic.nrMac Grant ID: 0
INFO: 1.504LteMacBase::sendLowerPackets, Sending packet LteMacPdu on port MAC_to_PHY
INFO: 	 H-ARQ TX: pdu (id 57252 ) extracted from process 0 codeword 0 for node with id 34
** Event #241762  t=1.505  MultiMec_v3.ue[6].cellularNic.nrMac (NRMacUe, id=8855)  on selfmsg ttiTick_ (omnetpp::cMessage, id=54946)

INFO: ----- UE MAIN LOOP -----
INFO: 1.505NRMacUe::handleSelfMessage 2055 - HARQ process 6
INFO: 1.505 NRMacUe::handleSelfMessage 2055 NO configured grant
INFO: 1.505 LteMacUeD2D::checkRAC , Ue  2055, racTimer : 0 maxRacTryOuts : 0, raRespTimer:0
INFO: LteMacUeD2D::sendLowerPackets UE sendLowerPackets nodeId_ 2055 full path is MultiMec_v3.ue[6].cellularNic.nrMac Grant ID: 0
INFO: 1.505LteMacBase::sendLowerPackets, Sending packet RacRequest on port MAC_to_PHY
INFO: 1.505 Ue  2055 cell 34 ,RAC request sent to PHY
INFO: 1.505 NRMacUe::handleSelfMessage - incrementing counter for HARQ processes 6 --> 7
INFO: --- END UE MAIN LOOP ---

The 'LteMacUeD2D::makeBsr() - BSR with size 50created' shows that the BRS runs and the method will not run the next part of code:

        // In a D2D communication if BSR was created above this part isn't executed
        // Build a MAC PDU for each scheduled user on each codeword
        std::map<double, LteMacScheduleList*>::iterator cit = scheduleList_.begin();
        for (; cit != scheduleList_.end(); ++cit)
        {
            double carrierFreq = cit->first;

            // skip if this is not the turn of this carrier
            if (getNumerologyPeriodCounter(binder_->getNumerologyIndexFromCarrierFreq(carrierFreq)) > 0)
                continue;

            LteMacScheduleList::const_iterator it;
            for (it = cit->second->begin(); it != cit->second->end(); it++)
            {
                Packet* macPkt;

                MacCid destCid = it->first.first;
                Codeword cw = it->first.second;

                // get the direction (UL/D2D/D2D_MULTI) and the corresponding destination ID
                FlowControlInfo* lteInfo = &(connDesc_.at(destCid));
                MacNodeId destId = lteInfo->getDestId();
                Direction dir = (Direction)lteInfo->getDirection();

                std::pair<MacNodeId, Codeword> pktId = std::pair<MacNodeId, Codeword>(destId, cw);
                unsigned int sduPerCid = it->second;
   
                if (sduPerCid == 0 && !bsrTriggered_ && !bsrD2DMulticastTriggered_)
                    continue;

                if (macPduList_.find(carrierFreq) == macPduList_.end())
                {
                    MacPduList newList;
                    macPduList_[carrierFreq] = newList;
                }
                MacPduList::iterator pit = macPduList_[carrierFreq].find(pktId);

                // No packets for this user on this codeword
                if (pit == macPduList_[carrierFreq].end())
                {
                    // Create a PDU
                    macPkt = new Packet("LteMacPdu");
                    auto header = makeShared<LteMacPdu>();
                    header->setHeaderLength(MAC_HEADER);
                    macPkt->insertAtFront(header);

                    macPkt->addTagIfAbsent<CreationTimeTag>()->setCreationTime(NOW);
                    macPkt->addTagIfAbsent<UserControlInfo>()->setSourceId(getMacNodeId());
                    macPkt->addTagIfAbsent<UserControlInfo>()->setDestId(destId);
                    macPkt->addTagIfAbsent<UserControlInfo>()->setDirection(dir);
                    macPkt->addTagIfAbsent<UserControlInfo>()->setLcid(MacCidToLcid(SHORT_BSR));
                    macPkt->addTagIfAbsent<UserControlInfo>()->setCarrierFrequency(carrierFreq);

                    macPkt->addTagIfAbsent<UserControlInfo>()->setGrantId(schedulingGrant_[carrierFreq]->getGrandId());

                    if (usePreconfiguredTxParams_)
                        macPkt->addTagIfAbsent<UserControlInfo>()->setUserTxParams(preconfiguredTxParams_->dup());
                    else
                        macPkt->addTagIfAbsent<UserControlInfo>()->setUserTxParams(schedulingGrant_[carrierFreq]->getUserTxParams()->dup());

                    macPduList_[carrierFreq][pktId] = macPkt;
                }
                else
                {
                    //tianhao
                    std::cout << "Entered else branch: reusing existing macPkt" << std::endl;
                    // Never goes here because of the macPduList_.clear() at the beginning
                    macPkt = pit->second;

                    // tianhao
                       auto userInfo = macPkt->getTag<UserControlInfo>();
                       if (userInfo != nullptr) {
                           std::cout << "In else branch, existing macPkt Grant ID: " << userInfo->getGrantId() << std::endl;
                       } else {
                           std::cout << "In else branch, UserControlInfo not found in existing macPkt." << std::endl;
                       }
                }

                while (sduPerCid > 0)
                {
                    // Add SDU to PDU
                    // Find Mac Pkt
                    if (mbuf_.find(destCid) == mbuf_.end())
                        throw cRuntimeError("Unable to find mac buffer for cid %d", destCid);

                    if (mbuf_[destCid]->isEmpty())
                        throw cRuntimeError("Empty buffer for cid %d, while expected SDUs were %d", destCid, sduPerCid);

                    auto pkt = check_and_cast<Packet *>(mbuf_[destCid]->popFront());
                    if (pkt != NULL)
                    {
                        // multicast support
                        // this trick gets the group ID from the MAC SDU and sets it in the MAC PDU
                        auto infoVec = getTagsWithInherit<LteControlInfo>(pkt);
                        if (infoVec.empty())
                            throw cRuntimeError("No tag of type LteControlInfo found");

                        int32_t groupId =  infoVec.front().getMulticastGroupId();
                        if (groupId >= 0) // for unicast, group id is -1
                            macPkt->getTagForUpdate<UserControlInfo>()->setMulticastGroupId(groupId);

                        drop(pkt);

                        auto header = macPkt->removeAtFront<LteMacPdu>();
                        header->pushSdu(pkt);
                        macPkt->insertAtFront(header);
                        sduPerCid--;
                    }
                    else
                        throw cRuntimeError("NRMacUe::macPduMake - extracted SDU is NULL. Abort.");
                }

                // consider virtual buffers to compute BSR size
                size += macBuffers_[destCid]->getQueueOccupancy();

                if (size > 0)
                {
                    // take into account the RLC header size
                    if (connDesc_[destCid].getRlcType() == UM)
                        size += RLC_HEADER_UM;
                    else if (connDesc_[destCid].getRlcType() == AM)
                        size += RLC_HEADER_AM;
                }
            }
        }

In the NRMacUe::macPduMake function, once a BSR (Buffer Status Report) is created, bsrAlreadyMade is set to true. This results in the subsequent code, which is responsible for creating and processing user data PDUs, being skipped entirely, leading to it being 0.
I am a little confused about the BSR mechanism and the simulation seems works well if I comment out the BSR code. Do you think there are any logic issues of the original code leading to this error or some wrong parameter settings?

Any suggestions about this would be greatly appreciated!

giovanninardini · 2024-11-14T17:17:43Z

giovanninardini
Nov 14, 2024

Ok, let's give it another try.
It is correct that the code you mention is not executed in that case... the problem might be in the code above, then.

After this line, try to add the following one and see what happens:
info->setGrantId(git->second->getGrandId());

2 replies

Wynn-TH Nov 15, 2024
Author

Thank you so much, Giovanni!
This works! The UE can send the BSR PDU with the correct grantId. However, when the base station receives it, another error occurs. Could you have a look at the log and give some advice about this? I would greatly appreciate any insights or suggestions you may have!

INFO: 1.507 LteAmc::blocks2bytes Node 2055, Band 96, Codeword 0,  direction UL, blocks 0
INFO: 1.507 LteAmc::blocks2bytes Resource Blocks: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteAmc::blocks2bytes Node 2055, Band 97, Codeword 0,  direction UL, blocks 0
INFO: 1.507 LteAmc::blocks2bytes Resource Blocks: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteAmc::blocks2bytes Node 2055, Band 98, Codeword 0,  direction UL, blocks 0
INFO: 1.507 LteAmc::blocks2bytes Resource Blocks: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteAmc::blocks2bytes Node 2055, Band 99, Codeword 0,  direction UL, blocks 0
INFO: 1.507 LteAmc::blocks2bytes Resource Blocks: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteAmc::blocks2bytes Available space: 0
INFO: 1.507 LteMacEnbD2D::sendGrants - granting 7 on cw 0
FATAL: 1.507 NRPacketFlowManagerGnb::grantSent - Added grant 57325 for nodeId 2055
INFO: 1.507LteMacBase::sendLowerPackets, Sending packet LteGrant on port MAC_to_PHY
INFO: ============================================ END UPLINK ============================================
INFO: ============================================ DOWNLINK ==============================================
INFO: LteSchedulerEnb::schedule performed by Node: 34
INFO: LteSchedulerEnb::schedule carrier [2]
INFO: ________________________start RAC+RTX _______________________________
INFO: ___________________________end RAC+RTX ________________________________
INFO: ___________________________start SCHED ________________________________
INFO: 1.507 LteMaxCI::schedule 34
INFO: ____________________________ end SCHED ________________________________
INFO: ----- START LteMacEnb::macSduRequest -----
INFO: ------ END LteMacEnb::macSduRequest ------
INFO: ========================================== END DOWNLINK ============================================
INFO: --- END ENB MAIN LOOP ---
** Event #242169  t=1.507  MultiMec_v3.gNodeB34.cellularNic.mac (NRMacGnb, id=3445)  on selfmsg flushHarqMsg (omnetpp::cMessage, id=137073)

INFO: LteHarqBufferTx::sendSelectedDown - no process selected in H-ARQ buffer, nothing to do
INFO: LteHarqBufferTx::sendSelectedDown - no process selected in H-ARQ buffer, nothing to do
INFO: LteHarqBufferTx::sendSelectedDown - no process selected in H-ARQ buffer, nothing to do
** Event #242261  t=1.508  MultiMec_v3.gNodeB34.cellularNic.mac (NRMacGnb, id=3445)  on selfmsg ttiTick_ (omnetpp::cMessage, id=3294)

INFO: -----ENB MAIN LOOP -----
INFO: H-ARQ RX: feedback sent to TX process 0 Codeword  0of node with id 2055 result: ACK
INFO: 1.508LteMacBase::sendLowerPackets, Sending packet harqFeedback on port MAC_to_PHY
INFO: LteHarqBufferRx::extractCorrectPdus H-ARQ RX: pdu (id 136951 ) extracted from process 0to be sent upper
INFO: grantID: 57228
INFO: it->grantID: 57228
FATAL: 1.508 NRPacketFlowManagerGnb::ulMacPduArrived - TB received from nodeId 2055 related to grantId 57228 after 0.006seconds
INFO: LteBsrBuffers : Added new BSR buffer for node: 2055 for Lcid: 1 Current BSR size: 50
INFO: LteSchedulerEnb::backlog - backlogged data for Logical Cid 134676481
INFO: 1.508LteSchedulerEnb::backlog CID notified 134676481
INFO: ============================================== UPLINK ==============================================
INFO: LteSchedulerEnb::schedule performed by Node: 34
INFO: LteSchedulerEnb::schedule carrier [2]
INFO: ________________________start RAC+RTX _______________________________
INFO: 1.508 LteSchedulerEnbUl::racschedule --------------------::[ START RAC-SCHEDULE ]::--------------------
INFO: 1.508 LteSchedulerEnbUl::racschedule eNodeB: 34 Direction: UL
INFO: 1.508 LteSchedulerEnbUl::racscheduleBackground - scheduling RAC for background UEs
INFO: 1.508 LteSchedulerEnbUl::racschedule --------------------::[  END RAC-SCHEDULE  ]::--------------------
INFO: ___________________________end RAC+RTX ________________________________
INFO: ___________________________start SCHED ________________________________
INFO: 1.508 LteMaxCI::schedule 34
INFO: 1.508 LteAmc::computeTxParams --------------::[ START ]::--------------
INFO: 1.508 LteAmc::computeTxParams CellId: 34
INFO: 1.508 LteAmc::computeTxParams NodeId: 2055
INFO: 1.508 LteAmc::computeTxParams Direction: D2D
INFO: 1.508 LteAmc::computeTxParams - - - - - - - - - - - - - - - - - - - - -
INFO: 1.508 LteAmc::computeTxParams RB allocation type: localized
INFO: 1.508 LteAmc::computeTxParams - - - - - - - - - - - - - - - - - - - - -
INFO: 1.508 AmcPilotAuto::computeTxParams for UE 2055, direction D2D
<!> LteAmc::getFeedback(): Unrecognized direction -- in module (NRMacGnb) MultiMec_v3.gNodeB34.cellularNic.mac (id=3445), at t=1.508s, event #242261

Wynn-TH Nov 18, 2024
Author

Hi Giovanni,

I believe I have identified the cause of the <!> LteAmc::getFeedback(): Unrecognized direction error.

In the NRMacUe::macPduMake function, the Lcid is set to either D2D_MULTI_SHORT_BSR or D2D_SHORT_BSR when the direction is UL as shown below:

if (bsrD2DMulticastTriggered_)
{
    info->setLcid(D2D_MULTI_SHORT_BSR);
    bsrD2DMulticastTriggered_ = false;
}
else
     info->setLcid(D2D_SHORT_BSR);

Subsequently, when the eNodeB receives this BSR, the direction is modified in the LteMaxCi::prepareSchedule function:

Direction dir;
        if (direction_ == UL)
            dir = (MacCidToLcid(cid) == D2D_SHORT_BSR) ? D2D : (MacCidToLcid(cid) == D2D_MULTI_SHORT_BSR) ? D2D_MULTI : direction_;
        else
            dir = DL;

Later, in the following function:

const LteSummaryFeedback& LteAmc::getFeedback(MacNodeId id, Remote antenna, TxMode txMode, const Direction dir, double carrierFrequency)
{
    MacNodeId nh = getNextHop(id);
    if (id != nh)
        EV << NOW << " LteAmc::getFeedback detected " << nh << " as nexthop for " << id << "\n";
    id = nh;

    if (dir != DL && dir != UL)
        throw cRuntimeError("LteAmc::getFeedback(): Unrecognized direction");

    History_* history = getHistory(dir, carrierFrequency);
    std::map<MacNodeId, unsigned int>* nodeIndex = (dir == DL) ? &dlNodeIndex_ : &ulNodeIndex_;

    return (*history).at(antenna).at((*nodeIndex).at(id)).at(txMode).get();
}

The error occurs because the LteAmc::getFeedback function is unable to process a D2D direction.

To resolve this, a potential fix is to add the following line after this line:
info->setLcid(SHORT_BSR);

Provide feedback

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