Do not update FCnt for re-transmissions

This commit fixes issue #68. In addition to remove the line that updates
the FCnt, this commit also introduces a new example to test the behavior
of re-transmissions, along with some changes in the NetworkScheduler
to remove its reliance on the frame counter to determine whether a
packet was received by another gateway already.

examples/frame-counter-update.cc

@@ -0,0 +1,266 @@
+/*
+ * This script simulates a complex scenario with multiple gateways and end
+ * devices. The metric of interest for this script is the throughput of the
+ * network.
+ */
+
+#include "ns3/callback.h"
+#include "ns3/end-device-lora-phy.h"
+#include "ns3/gateway-lora-phy.h"
+#include "ns3/class-a-end-device-lorawan-mac.h"
+#include "ns3/gateway-lorawan-mac.h"
+#include "ns3/lorawan-mac-header.h"
+#include "ns3/one-shot-sender-helper.h"
+#include "ns3/simulator.h"
+#include "ns3/log.h"
+#include "ns3/pointer.h"
+#include "ns3/constant-position-mobility-model.h"
+#include "ns3/lora-helper.h"
+#include "ns3/node-container.h"
+#include "ns3/mobility-helper.h"
+#include "ns3/position-allocator.h"
+#include "ns3/double.h"
+#include "ns3/random-variable-stream.h"
+#include "ns3/periodic-sender-helper.h"
+#include "ns3/command-line.h"
+#include "ns3/network-server-helper.h"
+#include "ns3/correlated-shadowing-propagation-loss-model.h"
+#include "ns3/building-penetration-loss.h"
+#include "ns3/building-allocator.h"
+#include "ns3/buildings-helper.h"
+#include "ns3/forwarder-helper.h"
+#include <algorithm>
+#include <ctime>
+
+using namespace ns3;
+using namespace lorawan;
+
+NS_LOG_COMPONENT_DEFINE ("FrameCounterUpdateExample");
+
+// Network settings
+int nGateways = 1;
+double simulationTime = 3600;
+
+void
+OnPhySentPacket (Ptr<const Packet> packet, uint32_t index)
+{
+  Ptr<Packet> packetCopy = packet->Copy();
+
+  LorawanMacHeader mHdr;
+  packetCopy->RemoveHeader (mHdr);
+  LoraFrameHeader fHdr;
+  packetCopy->RemoveHeader (fHdr);
+
+  NS_LOG_DEBUG ("Sent a packet with Frame Counter " << fHdr.GetFCnt());
+  // NS_LOG_DEBUG ("MAC Header:");
+  // NS_LOG_DEBUG (mHdr);
+  // NS_LOG_DEBUG ("Frame Header:");
+  // NS_LOG_DEBUG (fHdr);
+}
+
+void
+OnMacPacketOutcome (uint8_t transmissions, bool successful, Time firstAttempt, Ptr<Packet> packet)
+{
+  if (successful)
+  {
+    NS_LOG_INFO ("Packet was successful");
+  }
+  else
+  {
+    NS_LOG_INFO ("Giving up");
+  }
+}
+
+void
+ChangeEndDevicePosition (Ptr<Node> endDevice, bool inRange)
+{
+  if (inRange)
+    {
+      NS_LOG_INFO ("Moving ED in range");
+      endDevice->GetObject<MobilityModel> ()->SetPosition (Vector(0.0, 0.0, 0.0));
+    }
+  else
+    {
+      NS_LOG_INFO ("Moving ED out of range");
+      endDevice->GetObject<MobilityModel> ()->SetPosition (Vector(10000.0, 0.0, 0.0));
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+
+  CommandLine cmd;
+  cmd.AddValue ("simulationTime", "The time for which to simulate", simulationTime);
+  cmd.AddValue ("MaxTransmissions",
+                "ns3::EndDeviceLorawanMac::MaxTransmissions");
+  cmd.AddValue ("MType",
+                "ns3::EndDeviceLorawanMac::MType");
+  cmd.Parse (argc, argv);
+
+  // Set up logging
+  LogComponentEnable ("FrameCounterUpdateExample", LOG_LEVEL_ALL);
+
+  /***********
+   *  Setup  *
+   ***********/
+
+  // Mobility
+  MobilityHelper mobility;
+  Ptr<ListPositionAllocator> allocator = CreateObject<ListPositionAllocator> ();
+  // Make it so that nodes are at a certain height > 0
+  allocator->Add (Vector (100000.0, 0.0, 15.0)); // ED position
+  allocator->Add (Vector (0.0, 0.0, 15.0)); // GW position
+  mobility.SetPositionAllocator (allocator);
+  mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");
+
+  /************************
+   *  Create the channel  *
+   ************************/
+
+  // Create the lora channel object
+  Ptr<LogDistancePropagationLossModel> loss = CreateObject<LogDistancePropagationLossModel> ();
+  loss->SetPathLossExponent (3.76);
+  loss->SetReference (1, 7.7);
+
+  Ptr<PropagationDelayModel> delay = CreateObject<ConstantSpeedPropagationDelayModel> ();
+
+  Ptr<LoraChannel> channel = CreateObject<LoraChannel> (loss, delay);
+
+  /************************
+   *  Create the helpers  *
+   ************************/
+
+  // Create the LoraPhyHelper
+  LoraPhyHelper phyHelper = LoraPhyHelper ();
+  phyHelper.SetChannel (channel);
+
+  // Create the LorawanMacHelper
+  LorawanMacHelper macHelper = LorawanMacHelper ();
+
+  // Create the LoraHelper
+  LoraHelper helper = LoraHelper ();
+  helper.EnablePacketTracking (); // Output filename
+
+  //Create the NetworkServerHelper
+  NetworkServerHelper nsHelper = NetworkServerHelper ();
+
+  //Create the ForwarderHelper
+  ForwarderHelper forHelper = ForwarderHelper ();
+
+  /************************
+   *  Create End Devices  *
+   ************************/
+
+  // Create a set of nodes
+  NodeContainer endDevices;
+  endDevices.Create (1);
+
+  // Assign a mobility model to each node
+  mobility.Install (endDevices);
+
+  // Make it so that nodes are at a certain height > 0
+  for (NodeContainer::Iterator j = endDevices.Begin (); j != endDevices.End (); ++j)
+    {
+      Ptr<MobilityModel> mobility = (*j)->GetObject<MobilityModel> ();
+      Vector position = mobility->GetPosition ();
+      position.z = 1.2;
+      mobility->SetPosition (position);
+    }
+
+  // Create the LoraNetDevices of the end devices
+  uint8_t nwkId = 54;
+  uint32_t nwkAddr = 1864;
+  Ptr<LoraDeviceAddressGenerator> addrGen =
+      CreateObject<LoraDeviceAddressGenerator> (nwkId, nwkAddr);
+
+  // Create the LoraNetDevices of the end devices
+  macHelper.SetAddressGenerator (addrGen);
+  phyHelper.SetDeviceType (LoraPhyHelper::ED);
+  macHelper.SetDeviceType (LorawanMacHelper::ED_A);
+  macHelper.Set("DataRate", UintegerValue(5));
+  helper.Install (phyHelper, macHelper, endDevices);
+
+  // Connect trace sources
+  for (NodeContainer::Iterator j = endDevices.Begin (); j != endDevices.End (); ++j)
+    {
+      Ptr<Node> node = *j;
+      Ptr<LoraNetDevice> loraNetDevice = node->GetDevice (0)->GetObject<LoraNetDevice> ();
+      Ptr<LoraPhy> phy = loraNetDevice->GetPhy ();
+      Ptr<EndDeviceLorawanMac> mac = loraNetDevice->GetMac ()->GetObject<EndDeviceLorawanMac> ();
+      phy->TraceConnectWithoutContext("StartSending", MakeCallback(&OnPhySentPacket));
+      mac->TraceConnectWithoutContext("RequiredTransmissions", MakeCallback(&OnMacPacketOutcome));
+    }
+
+  // Create the gateway nodes (allocate them uniformely on the disc)
+  NodeContainer gateways;
+  gateways.Create (nGateways);
+
+  // Make it so that nodes are at a certain height > 0
+  mobility.SetPositionAllocator (allocator);
+  mobility.Install (gateways);
+
+  // Create a netdevice for each gateway
+  phyHelper.SetDeviceType (LoraPhyHelper::GW);
+  macHelper.SetDeviceType (LorawanMacHelper::GW);
+  helper.Install (phyHelper, macHelper, gateways);
+
+  NS_LOG_INFO ("Completed configuration");
+
+  /*********************************************
+   *  Install applications on the end devices  *
+   *********************************************/
+
+  Time appStopTime = Seconds (simulationTime);
+  OneShotSenderHelper appHelper = OneShotSenderHelper ();
+  appHelper.SetSendTime (Seconds (0));
+  ApplicationContainer appContainer = appHelper.Install (endDevices);
+  appHelper.SetSendTime (Seconds (100));
+  appContainer.Add(appHelper.Install (endDevices));
+  appHelper.SetSendTime (Seconds (200));
+  appContainer.Add(appHelper.Install (endDevices));
+
+  appContainer.Start (Seconds (0));
+  appContainer.Stop (appStopTime);
+
+  Simulator::Schedule (Seconds (110), &ChangeEndDevicePosition, endDevices.Get(0), true);
+  Simulator::Schedule (Seconds (201), &ChangeEndDevicePosition, endDevices.Get(0), false);
+  Simulator::Schedule (Seconds (204), &ChangeEndDevicePosition, endDevices.Get(0), true);
+
+  /**************************
+   *  Create Network Server  *
+   ***************************/
+
+  // Create the NS node
+  NodeContainer networkServer;
+  networkServer.Create (1);
+
+  // Create a NS for the network
+  nsHelper.SetEndDevices (endDevices);
+  nsHelper.SetGateways (gateways);
+  nsHelper.Install (networkServer);
+
+  //Create a forwarder for each gateway
+  forHelper.Install (gateways);
+
+  ////////////////
+  // Simulation //
+  ////////////////
+
+  Simulator::Stop (appStopTime + Hours (1));
+
+  NS_LOG_INFO ("Running simulation...");
+  Simulator::Run ();
+
+  Simulator::Destroy ();
+
+  ///////////////////////////
+  // Print results to file //
+  ///////////////////////////
+
+  LoraPacketTracker &tracker = helper.GetPacketTracker ();
+  NS_LOG_INFO ("Printing total sent MAC-layer packets and successful MAC-layer packets");
+  std::cout << tracker.CountMacPacketsGlobally (Seconds (0), appStopTime + Hours (1)) << std::endl;
+
+  return 0;
+}

examples/wscript

@@ -22,3 +22,6 @@ def build(bld):
 
     obj = bld.create_ns3_program('parallel-reception-example', ['lorawan'])
     obj.source = 'parallel-reception-example.cc'
+
+    obj = bld.create_ns3_program('frame-counter-update', ['lorawan'])
+    obj.source = 'frame-counter-update.cc'

model/end-device-lorawan-mac.cc

@@ -287,8 +287,6 @@ EndDeviceLorawanMac::DoSend (Ptr<Packet> packet)
       if (m_retxParams.waitingAck)
         {
 
-          m_currentFCnt++;
-
           // Remove the headers
           LorawanMacHeader macHdr;
           LoraFrameHeader frameHdr;

model/end-device-status.cc

@@ -365,6 +365,24 @@ EndDeviceStatus::AddMACCommand (Ptr<MacCommand> macCommand)
   m_reply.frameHeader.AddCommand (macCommand);
 }
 
+bool
+EndDeviceStatus::HasReceiveWindowOpportunityScheduled ()
+{
+  return m_receiveWindowEvent.IsRunning();
+}
+
+void
+EndDeviceStatus::SetReceiveWindowOpportunity (EventId event)
+{
+  m_receiveWindowEvent = event;
+}
+
+void
+EndDeviceStatus::RemoveReceiveWindowOpportunity (void)
+{
+  Simulator::Cancel(m_receiveWindowEvent);
+}
+
 std::map<double, Address>
 EndDeviceStatus::GetPowerGatewayMap (void)
 {

model/end-device-status.h

@@ -294,12 +294,21 @@ class EndDeviceStatus : public Object
    */
   void UpdateGatewayData (GatewayList gwList, Address gwAddress, double rcvPower);
 
+  /**
+   * Returns whether we already decided we will schedule a transmission to this ED
+   */
+  bool HasReceiveWindowOpportunityScheduled ();
+
+  void SetReceiveWindowOpportunity (EventId event);
+
+  void RemoveReceiveWindowOpportunity (void);
+
   /**
    * Return an ordered list of the best gateways.
    */
   std::map<double, Address> GetPowerGatewayMap (void);
 
-  struct Reply m_reply;   //<! Next reply intended for this device
+  struct Reply m_reply; //<! Next reply intended for this device
 
   LoraDeviceAddress m_endDeviceAddress;   //<! The address of this device
 
@@ -311,6 +320,7 @@ class EndDeviceStatus : public Object
   double m_firstReceiveWindowFrequency = 0;
   uint8_t m_secondReceiveWindowOffset = 0;
   double m_secondReceiveWindowFrequency = 869.525;
+  EventId m_receiveWindowEvent;
 
   ReceivedPacketList m_receivedPacketList;   //<! List of received packets