simuLTE_veins : Received feedback for an unexisting H-ARQ tx buffer

[aman gulia]

Hi OMNET++ team,

I did read the discussion on H-ARQ asked in this group regarding similar error. As you guys mentioned that new release will have fixed this issue, I would like to know if anyone has resolved this error yet.

I am new to simuLTE and I am trying to explore the CAR example under SIMULATION folder by varying the number of vehicles for VoIP D2D network configuration.
The default CAR example works for 10 UEs(or vehicles) but I want to run the same example with 20 vehicles so I generated random trips for the previous used heterogeneous.net.xml. 
Similarly, the changes I made in the configuration in .ini file are as follows:

##LTE specific parameters
#AMC module parameters
**.numUe = ${numUEs=20}
[config VoIP-D2D]
*.car[*].numUdpApps =1
*.car[0..9].udpApp[0].typename = "VoIPSender"
*.car[0..9].udpApp[0].destAddress =  "car["+string(ancestorIndex(1)+10)+"]"
*.car[10..19].udpApp[0].type="VoIPReceiver"

*.car[0..9].lteNic.d2dPeerAddresses = "car["+string(ancestorIndex(1)+10)+"]"

 

Error during the simulation:

** Event #312848  t=15.201 Highway.car[1].lteNic.mac (LteMacUeRealisticD2D, id=283)  on (LteHarqFeedback, id=163939)

INFO (LteMacUeRealisticD2D)Highway.car[1].lteNic.mac: LteMacBase : Received packet  from port PHY_to_MAC

INFO (LteMacUeRealisticD2D)Highway.car[1].lteNic.mac: 15.201Mac::fromPhy: node 1026 Received HARQ Feedback pkt

INFO (LteMacUeRealisticD2D)Highway.car[1].lteNic.mac: LteHarqBufferTx::receiveHarqFeedback - start

INFO (LteMacUeRealisticD2D)Highway.car[1].lteNic.mac: LteHarqUnitTx::pduFeedback - Welcome!

INFO (LteMacUeRealisticD2D)Highway.car[1].lteNic.mac:      pdu_ has been sent and received correctly

INFO (LteMacUeRealisticD2D)Highway.car[1].lteNic.mac: H-ARQ TX: feedback received for process 2 codeword 0 result is ACK

** Event #312849  t=15.201 Highway.car[0].lteNic.phy (LtePhyUeD2D, id=255)  on harqFeedback-grant (LteAirFrame, id=163772)

INFO (LtePhyUeD2D)Highway.car[0].lteNic.phy:  LtePhyBase::handleMessage - new message received

INFO (LtePhyUeD2D)Highway.car[0].lteNic.phy: LtePhyUeD2D: received new LteAirFrame with ID 163772 from channel

** Event #312850  t=15.201 Highway.car[0].lteNic.mac (LteMacUeRealisticD2D, id=254)  on (LteHarqFeedback, id=163941)

INFO (LteMacUeRealisticD2D)Highway.car[0].lteNic.mac: LteMacBase : Received packet  from port PHY_to_MAC

INFO (LteMacUeRealisticD2D)Highway.car[0].lteNic.mac: 15.201Mac::fromPhy: node 1025 Received HARQ Feedback pkt

<!> Mac::fromPhy(): Received feedback for an unexisting H-ARQ tx buffer -- in module (LteMacUeRealisticD2D) Highway.car[0].lteNic.mac (id=254), at t=15.201s, event #312850

Upon going through LteMacBase.cc under the method void LteMacBase::fromPhy(cPacket *pkt):

if (userInfo->getFrameType() == HARQPKT)

{

    // H-ARQ feedback, send it to TX buffer of source

    HarqTxBuffers::iterator htit = harqTxBuffers_.find(src);

    EV << NOW << "Mac::fromPhy: node " << nodeId_ << " Received HARQ Feedback pkt" << endl;

    if (htit == harqTxBuffers_.end())

    {

        // if a feedback arrives, a tx buffer must exists (unless it is an handover scenario

        // where the harq buffer was deleted but a feedback was in transit)

        // this case must be taken care of

        if (binder_->hasUeHandoverTriggered(nodeId_) || binder_->hasUeHandoverTriggered(src))

            return;

        throw cRuntimeError("Mac::fromPhy(): Received feedback for an unexisting H-ARQ tx buffer");

    }

    LteHarqFeedback *hfbpkt = check_and_cast<LteHarqFeedback *>(pkt);

    htit->second->receiveHarqFeedback(hfbpkt);

}

else if (userInfo->getFrameType() == FEEDBACKPKT) 

        .....

Htit is defined as :

// H-ARQ feedback, send it to TX buffer of source

HarqTxBuffers::iterator htit = harqTxBuffers_.find(src)

What could be the reason for H-ARQ buffer non-existent?

Am I missing any configuration detail?

Any help is appreciated.

Kindly let me know if any other details/screenshots are required to troubleshoot or replicate the error.

Thanks in advance

Best Regards,

Aman