NS3 LTE基于X2接口的内部切换

相比较上一篇含有EPC网络的LTE仿真程序，本文又增加了基于X2接口的内部切换仿真流程。下面将是这样的网络拓扑：

一个UE，两个eNB，一个作为源基站，一个作为切换基站

#include "ns3/core-module.h"#include "ns3/network-module.h"#include "ns3/internet-module.h"#include "ns3/mobility-module.h"#include "ns3/lte-module.h"#include "ns3/applications-module.h"#include "ns3/point-to-point-module.h"#include "ns3/config-store-module.h"using namespace ns3;NS_LOG_COMPONENT_DEFINE ("LenaX2HandoverExample");//Define Trace sinks functionvoidNotifyConnectionEstablishedUe (std::string context,                               uint64_t imsi,                               uint16_t cellid,                               uint16_t rnti){  std::cout << Simulator::Now ().GetSeconds () << " " << context            << " UE IMSI " << imsi            << ": connected to CellId " << cellid            << " with RNTI " << rnti            << std::endl;}voidNotifyHandoverStartUe (std::string context,                       uint64_t imsi,                       uint16_t cellid,                       uint16_t rnti,                       uint16_t targetCellId){  std::cout << Simulator::Now ().GetSeconds () << " " << context            << " UE IMSI " << imsi            << ": previously connected to CellId " << cellid            << " with RNTI " << rnti            << ", doing handover to CellId " << targetCellId            << std::endl;}voidNotifyHandoverEndOkUe (std::string context,                       uint64_t imsi,                       uint16_t cellid,                       uint16_t rnti){  std::cout << Simulator::Now ().GetSeconds () << " " << context            << " UE IMSI " << imsi            << ": successful handover to CellId " << cellid            << " with RNTI " << rnti            << std::endl;}voidNotifyConnectionEstablishedEnb (std::string context,                                uint64_t imsi,                                uint16_t cellid,                                uint16_t rnti){  std::cout << Simulator::Now ().GetSeconds () << " " << context            << " eNB CellId " << cellid            << ": successful connection of UE with IMSI " << imsi            << " RNTI " << rnti            << std::endl;}voidNotifyHandoverStartEnb (std::string context,                        uint64_t imsi,                        uint16_t cellid,                        uint16_t rnti,                        uint16_t targetCellId){  std::cout << Simulator::Now ().GetSeconds () << " " << context            << " eNB CellId " << cellid            << ": start handover of UE with IMSI " << imsi            << " RNTI " << rnti            << " to CellId " << targetCellId            << std::endl;}voidNotifyHandoverEndOkEnb (std::string context,                        uint64_t imsi,                        uint16_t cellid,                        uint16_t rnti){  std::cout << Simulator::Now ().GetSeconds () << " " << context            << " eNB CellId " << cellid            << ": completed handover of UE with IMSI " << imsi            << " RNTI " << rnti            << std::endl;}/** * Sample simulation script for a X2-based handover. * It instantiates two eNodeB, attaches one UE to the 'source' eNB and * triggers a handover of the UE towards the 'target' eNB. */intmain (int argc, char *argv[]){  // LogLevel logLevel = (LogLevel)(LOG_PREFIX_FUNC | LOG_PREFIX_TIME | LOG_LEVEL_ALL);  // LogComponentEnable ("LteHelper", logLevel);  // LogComponentEnable ("EpcHelper", logLevel);  // LogComponentEnable ("EpcEnbApplication", logLevel);  // LogComponentEnable ("EpcX2", logLevel);  // LogComponentEnable ("EpcSgwPgwApplication", logLevel);  // LogComponentEnable ("LteEnbRrc", logLevel);  // LogComponentEnable ("LteEnbNetDevice", logLevel);  // LogComponentEnable ("LteUeRrc", logLevel);  // LogComponentEnable ("LteUeNetDevice", logLevel);  uint16_t numberOfUes = 1;  uint16_t numberOfEnbs = 2;  uint16_t numBearersPerUe = 2;  double simTime = 0.300;  double distance = 100.0;  // change some default attributes so that they are reasonable for  // this scenario, but do this before processing command line  // arguments, so that the user is allowed to override these settings  Config::SetDefault ("ns3::UdpClient::Interval", TimeValue (MilliSeconds (10)));  Config::SetDefault ("ns3::UdpClient::MaxPackets", UintegerValue (1000000));  Config::SetDefault ("ns3::LteHelper::UseIdealRrc", BooleanValue (false));  // Command line arguments  CommandLine cmd;  cmd.AddValue ("numberOfUes", "Number of UEs", numberOfUes);  cmd.AddValue ("numberOfEnbs", "Number of eNodeBs", numberOfEnbs);  cmd.AddValue ("simTime", "Total duration of the simulation (in seconds)", simTime);  cmd.Parse (argc, argv);  Ptr<LteHelper> lteHelper = CreateObject<LteHelper> ();  Ptr<PointToPointEpcHelper> epcHelper = CreateObject<PointToPointEpcHelper> ();  lteHelper->SetEpcHelper (epcHelper);//告诉lte 含有epc  lteHelper->SetSchedulerType ("ns3::RrFfMacScheduler");  lteHelper->SetHandoverAlgorithmType ("ns3::NoOpHandoverAlgorithm"); // disable automatic handover,选择切换算法,A2A4RsrpHandoverAlgorithm A3RsrpHandoverAlgorithm//epcHelper自动创建和配置PGW，下面取出PGW  Ptr<Node> pgw = epcHelper->GetPgwNode ();  // Create a single RemoteHost  NodeContainer remoteHostContainer;  remoteHostContainer.Create (1);  Ptr<Node> remoteHost = remoteHostContainer.Get (0);  InternetStackHelper internet;  internet.Install (remoteHostContainer);  // Create the Internet  PointToPointHelper p2ph;  p2ph.SetDeviceAttribute ("DataRate", DataRateValue (DataRate ("100Gb/s")));  p2ph.SetDeviceAttribute ("Mtu", UintegerValue (1500));  p2ph.SetChannelAttribute ("Delay", TimeValue (Seconds (0.010)));  NetDeviceContainer internetDevices = p2ph.Install (pgw, remoteHost);//在remoteHost pgw安装P2P设备  Ipv4AddressHelper ipv4h;  ipv4h.SetBase ("1.0.0.0", "255.0.0.0");  Ipv4InterfaceContainer internetIpIfaces = ipv4h.Assign (internetDevices);//为 remoteHostStaticRouting pgw分配IP  Ipv4Address remoteHostAddr = internetIpIfaces.GetAddress (1);//取得remotehost IP  // Routing of the Internet Host (towards the LTE network)  Ipv4StaticRoutingHelper ipv4RoutingHelper;  Ptr<Ipv4StaticRouting> remoteHostStaticRouting = ipv4RoutingHelper.GetStaticRouting (remoteHost->GetObject<Ipv4> ());  // interface 0 is localhost, 1 is the p2p device  remoteHostStaticRouting->AddNetworkRouteTo (Ipv4Address ("7.0.0.0"), Ipv4Mask ("255.0.0.0"), 1);//UE默认在网络7.0.0.0//创建LTE接入网节点  NodeContainer ueNodes;  NodeContainer enbNodes;  enbNodes.Create (numberOfEnbs);  ueNodes.Create (numberOfUes);  // Install Mobility Model  Ptr<ListPositionAllocator> positionAlloc = CreateObject<ListPositionAllocator> ();  for (uint16_t i = 0; i < numberOfEnbs; i++)    {      positionAlloc->Add (Vector (distance * 2 * i - distance, 0, 0));//enb初始位置（distance*2i-distance,0,0）    }  for (uint16_t i = 0; i < numberOfUes; i++)    {      positionAlloc->Add (Vector (0, 0, 0));//UE初始位置（0,0,0）    }  MobilityHelper mobility;  mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");  mobility.SetPositionAllocator (positionAlloc);  mobility.Install (enbNodes);  mobility.Install (ueNodes);  // Install LTE Devices in eNB and UEs  NetDeviceContainer enbLteDevs = lteHelper->InstallEnbDevice (enbNodes);  NetDeviceContainer ueLteDevs = lteHelper->InstallUeDevice (ueNodes);  // Install the IP stack on the UEs  internet.Install (ueNodes);  Ipv4InterfaceContainer ueIpIfaces;  ueIpIfaces = epcHelper->AssignUeIpv4Address (NetDeviceContainer (ueLteDevs));  //建立网关在下面循环里  // Attach all UEs to the first eNodeB  for (uint16_t i = 0; i < numberOfUes; i++)    {      lteHelper->Attach (ueLteDevs.Get (i), enbLteDevs.Get (0));//指定所有UE关联到enbdev(0)    }//未指定承载则默认EPS承载将会建立  NS_LOG_LOGIC ("setting up applications");//控制台输出提醒开始安装app  // Install and start applications on UEs and remote host  uint16_t dlPort = 10000;  uint16_t ulPort = 20000;  // randomize a bit start times to avoid simulation artifacts  // (e.g., buffer overflows due to packet transmissions happening  // exactly at the same time)  Ptr<UniformRandomVariable> startTimeSeconds = CreateObject<UniformRandomVariable> ();  startTimeSeconds->SetAttribute ("Min", DoubleValue (0));  startTimeSeconds->SetAttribute ("Max", DoubleValue (0.010));  for (uint32_t u = 0; u < numberOfUes; ++u)    {      Ptr<Node> ue = ueNodes.Get (u);      // Set the default gateway for the UE      Ptr<Ipv4StaticRouting> ueStaticRouting = ipv4RoutingHelper.GetStaticRouting (ue->GetObject<Ipv4> ());      ueStaticRouting->SetDefaultRoute (epcHelper->GetUeDefaultGatewayAddress (), 1);      for (uint32_t b = 0; b < numBearersPerUe; ++b)        {          ++dlPort;          ++ulPort;          ApplicationContainer clientApps;          ApplicationContainer serverApps;          NS_LOG_LOGIC ("installing UDP DL app for UE " << u);          UdpClientHelper dlClientHelper (ueIpIfaces.GetAddress (u), dlPort);//dl 目的 Usr          clientApps.Add (dlClientHelper.Install (remoteHost));//客户端是remotehost          PacketSinkHelper dlPacketSinkHelper ("ns3::UdpSocketFactory",                                               InetSocketAddress (Ipv4Address::GetAny (), dlPort));          serverApps.Add (dlPacketSinkHelper.Install (ue));          NS_LOG_LOGIC ("installing UDP UL app for UE " << u);          UdpClientHelper ulClientHelper (remoteHostAddr, ulPort);//ul 目的 remoteHost          clientApps.Add (ulClientHelper.Install (ue));          PacketSinkHelper ulPacketSinkHelper ("ns3::UdpSocketFactory",                                               InetSocketAddress (Ipv4Address::GetAny (), ulPort));          serverApps.Add (ulPacketSinkHelper.Install (remoteHost));          Ptr<EpcTft> tft = Create<EpcTft> ();          EpcTft::PacketFilter dlpf;          dlpf.localPortStart = dlPort;          dlpf.localPortEnd = dlPort;          tft->Add (dlpf);          EpcTft::PacketFilter ulpf;          ulpf.remotePortStart = ulPort;          ulpf.remotePortEnd = ulPort;          tft->Add (ulpf);          EpsBearer bearer (EpsBearer::NGBR_VIDEO_TCP_DEFAULT);          lteHelper->ActivateDedicatedEpsBearer (ueLteDevs.Get (u), bearer, tft);//不再是默认EPS承载而是专用承载          Time startTime = Seconds (startTimeSeconds->GetValue ());//随机开始          serverApps.Start (startTime);          clientApps.Start (startTime);        } // end for bearer    }//end for Usr  // Add X2 inteface  lteHelper->AddX2Interface (enbNodes);//至少两个enb，每两个之间加入X2  // X2-based Handover  lteHelper->HandoverRequest (Seconds (0.100), ueLteDevs.Get (0), enbLteDevs.Get (0), enbLteDevs.Get (1));//人工触发切换  // Uncomment to enable PCAP tracing  //p2ph.EnablePcapAll("lena-x2-handover");  lteHelper->EnablePhyTraces ();  lteHelper->EnableMacTraces ();  lteHelper->EnableRlcTraces ();  lteHelper->EnablePdcpTraces ();  Ptr<RadioBearerStatsCalculator> rlcStats = lteHelper->GetRlcStats ();  rlcStats->SetAttribute ("EpochDuration", TimeValue (Seconds (0.05)));  Ptr<RadioBearerStatsCalculator> pdcpStats = lteHelper->GetPdcpStats ();  pdcpStats->SetAttribute ("EpochDuration", TimeValue (Seconds (0.05)));  // connect custom trace sinks for RRC connection establishment and handover notification  Config::Connect ("/NodeList/*/DeviceList/*/LteEnbRrc/ConnectionEstablished",                   MakeCallback (&NotifyConnectionEstablishedEnb));  Config::Connect ("/NodeList/*/DeviceList/*/LteUeRrc/ConnectionEstablished",                   MakeCallback (&NotifyConnectionEstablishedUe));  Config::Connect ("/NodeList/*/DeviceList/*/LteEnbRrc/HandoverStart",                   MakeCallback (&NotifyHandoverStartEnb));  Config::Connect ("/NodeList/*/DeviceList/*/LteUeRrc/HandoverStart",                   MakeCallback (&NotifyHandoverStartUe));  Config::Connect ("/NodeList/*/DeviceList/*/LteEnbRrc/HandoverEndOk",                   MakeCallback (&NotifyHandoverEndOkEnb));  Config::Connect ("/NodeList/*/DeviceList/*/LteUeRrc/HandoverEndOk",                   MakeCallback (&NotifyHandoverEndOkUe));//利用类Config的一个静态成员函数Connect将二者关联source sink ,MakeCallback 使参数函数变成回调函数  Simulator::Stop (Seconds (simTime));  Simulator::Run ();  // GtkConfigStore config;  // config.ConfigureAttributes ();  Simulator::Destroy ();  return 0;}

以上实现了通过默认EPS承载建立起UE到远程网络remotehost之间的通信。