A Discrete-Event Network Simulator
API
ns3::A2A4RsrqHandoverAlgorithm Class Reference

Handover algorithm implementation based on RSRQ measurements, Event A2 and Event A4. More...

#include "a2-a4-rsrq-handover-algorithm.h"

+ Inheritance diagram for ns3::A2A4RsrqHandoverAlgorithm:
+ Collaboration diagram for ns3::A2A4RsrqHandoverAlgorithm:

Classes

class  UeMeasure
 Measurements reported by a UE for a cell ID. More...
 

Public Member Functions

 A2A4RsrqHandoverAlgorithm ()
 Creates an A2-A4-RSRQ handover algorithm instance. More...
 
virtual ~A2A4RsrqHandoverAlgorithm ()
 
virtual LteHandoverManagementSapProviderGetLteHandoverManagementSapProvider ()
 Export the "provider" part of the Handover Management SAP interface. More...
 
virtual void SetLteHandoverManagementSapUser (LteHandoverManagementSapUser *s)
 Set the "user" part of the Handover Management SAP interface that this handover algorithm instance will interact with. More...
 
- Public Member Functions inherited from ns3::LteHandoverAlgorithm
 LteHandoverAlgorithm ()
 
virtual ~LteHandoverAlgorithm ()
 
virtual LteHandoverManagementSapProviderGetLteHandoverManagementSapProvider ()=0
 Export the "provider" part of the Handover Management SAP interface. More...
 
virtual void SetLteHandoverManagementSapUser (LteHandoverManagementSapUser *s)=0
 Set the "user" part of the Handover Management SAP interface that this handover algorithm instance will interact with. More...
 
- Public Member Functions inherited from ns3::Object
 Object ()
 Constructor. More...
 
virtual ~Object ()
 Destructor. More...
 
void AggregateObject (Ptr< Object > other)
 Aggregate two Objects together. More...
 
void Dispose (void)
 Dispose of this Object. More...
 
AggregateIterator GetAggregateIterator (void) const
 Get an iterator to the Objects aggregated to this one. More...
 
virtual TypeId GetInstanceTypeId (void) const
 Get the most derived TypeId for this Object. More...
 
template<>
Ptr< ObjectGetObject () const
 Specialization of () for objects of type ns3::Object. More...
 
template<typename T >
Ptr< T > GetObject (TypeId tid) const
 Get a pointer to the requested aggregated Object by TypeId. More...
 
template<>
Ptr< ObjectGetObject (TypeId tid) const
 Specialization of (TypeId tid) for objects of type ns3::Object. More...
 
template<typename T >
Ptr< T > GetObject (void) const
 Get a pointer to the requested aggregated Object. More...
 
void Initialize (void)
 Invoke DoInitialize on all Objects aggregated to this one. More...
 
bool IsInitialized (void) const
 Check if the object has been initialized. More...
 
- Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
 SimpleRefCount ()
 Default constructor. More...
 
 SimpleRefCount (const SimpleRefCount &o)
 Copy constructor. More...
 
uint32_t GetReferenceCount (void) const
 Get the reference count of the object. More...
 
SimpleRefCountoperator= (const SimpleRefCount &o)
 Assignment operator. More...
 
void Ref (void) const
 Increment the reference count. More...
 
void Unref (void) const
 Decrement the reference count. More...
 
- Public Member Functions inherited from ns3::ObjectBase
virtual ~ObjectBase ()
 Virtual destructor. More...
 
void GetAttribute (std::string name, AttributeValue &value) const
 Get the value of an attribute, raising fatal errors if unsuccessful. More...
 
bool GetAttributeFailSafe (std::string name, AttributeValue &value) const
 Get the value of an attribute without raising erros. More...
 
virtual TypeId GetInstanceTypeId (void) const =0
 Get the most derived TypeId for this Object. More...
 
void SetAttribute (std::string name, const AttributeValue &value)
 Set a single attribute, raising fatal errors if unsuccessful. More...
 
bool SetAttributeFailSafe (std::string name, const AttributeValue &value)
 Set a single attribute without raising errors. More...
 
bool TraceConnect (std::string name, std::string context, const CallbackBase &cb)
 Connect a TraceSource to a Callback with a context. More...
 
bool TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
 Connect a TraceSource to a Callback without a context. More...
 
bool TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
 Disconnect from a TraceSource a Callback previously connected with a context. More...
 
bool TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
 Disconnect from a TraceSource a Callback previously connected without a context. More...
 

Static Public Member Functions

static TypeId GetTypeId ()
 Get the type ID. More...
 
- Static Public Member Functions inherited from ns3::LteHandoverAlgorithm
static TypeId GetTypeId ()
 Get the type ID. More...
 
- Static Public Member Functions inherited from ns3::Object
static TypeId GetTypeId (void)
 Register this type. More...
 
- Static Public Member Functions inherited from ns3::ObjectBase
static TypeId GetTypeId (void)
 Get the type ID. More...
 

Protected Member Functions

virtual void DoDispose ()
 Destructor implementation. More...
 
virtual void DoInitialize ()
 Initialize() implementation. More...
 
void DoReportUeMeas (uint16_t rnti, LteRrcSap::MeasResults measResults)
 Implementation of LteHandoverManagementSapProvider::ReportUeMeas. More...
 
virtual void DoDispose ()
 Destructor implementation. More...
 
virtual void DoReportUeMeas (uint16_t rnti, LteRrcSap::MeasResults measResults)=0
 Implementation of LteHandoverManagementSapProvider::ReportUeMeas. More...
 
- Protected Member Functions inherited from ns3::Object
 Object (const Object &o)
 Copy an Object. More...
 
virtual void DoDispose (void)
 Destructor implementation. More...
 
virtual void DoInitialize (void)
 Initialize() implementation. More...
 
virtual void NotifyNewAggregate (void)
 Notify all Objects aggregated to this one of a new Object being aggregated. More...
 
- Protected Member Functions inherited from ns3::ObjectBase
void ConstructSelf (const AttributeConstructionList &attributes)
 Complete construction of ObjectBase; invoked by derived classes. More...
 
virtual void NotifyConstructionCompleted (void)
 Notifier called once the ObjectBase is fully constructed. More...
 

Private Types

typedef std::map< uint16_t, Ptr< UeMeasure > > MeasurementRow_t
 Measurements reported by a UE for several cells. More...
 
typedef std::map< uint16_t, MeasurementRow_tMeasurementTable_t
 Measurements reported by several UEs. More...
 

Private Member Functions

void EvaluateHandover (uint16_t rnti, uint8_t servingCellRsrq)
 Called when Event A2 is detected, then trigger a handover if needed. More...
 
bool IsValidNeighbour (uint16_t cellId)
 Determines if a neighbour cell is a valid destination for handover. More...
 
void UpdateNeighbourMeasurements (uint16_t rnti, uint16_t cellId, uint8_t rsrq)
 Called when Event A4 is reported, then update the measurements table. More...
 

Private Attributes

std::vector< uint8_t > m_a2MeasIds
 The expected measurement identities for A2 measurements. More...
 
std::vector< uint8_t > m_a4MeasIds
 The expected measurement identities for A4 measurements. More...
 
LteHandoverManagementSapProviderm_handoverManagementSapProvider
 Receive API calls from the eNodeB RRC instance. More...
 
LteHandoverManagementSapUserm_handoverManagementSapUser
 Interface to the eNodeB RRC instance. More...
 
MeasurementTable_t m_neighbourCellMeasures
 Table of measurement reports from all UEs. More...
 
uint8_t m_neighbourCellOffset
 The NeighbourCellOffset attribute. More...
 
uint8_t m_servingCellThreshold
 The ServingCellThreshold attribute. More...
 

Friends

class MemberLteHandoverManagementSapProvider< A2A4RsrqHandoverAlgorithm >
 let the forwarder class access the protected and private members More...
 

Additional Inherited Members

Detailed Description

Handover algorithm implementation based on RSRQ measurements, Event A2 and Event A4.

Handover decision made by this algorithm is primarily based on Event A2 measurements (serving cell's RSRQ becomes worse than threshold). When the event is triggered, the first condition of handover is fulfilled.

Event A4 measurements (neighbour cell's RSRQ becomes better than threshold) are used to detect neighbouring cells and their respective RSRQ. When a neighbouring cell's RSRQ is higher than the serving cell's RSRQ by a certain offset, then the second condition of handover is fulfilled.

When the first and second conditions above are fulfilled, the algorithm informs the eNodeB RRC to trigger a handover.

The threshold for Event A2 can be configured in the ServingCellThreshold attribute. The offset used in the second condition can also be configured by setting the NeighbourCellOffset attribute.

The following code snippet is an example of using and configuring the handover algorithm in a simulation program:

Ptr<LteHelper> lteHelper = CreateObject<LteHelper> ();

NodeContainer enbNodes;
// configure the nodes here...

lteHelper->SetHandoverAlgorithmType ("ns3::A2A4RsrqHandoverAlgorithm");
lteHelper->SetHandoverAlgorithmAttribute ("ServingCellThreshold",
                                          UintegerValue (30));
lteHelper->SetHandoverAlgorithmAttribute ("NeighbourCellOffset",
                                          UintegerValue (1));
NetDeviceContainer enbLteDevs = lteHelper->InstallEnbDevice (enbNodes);
Note
Setting the handover algorithm type and attributes after the call to LteHelper::InstallEnbDevice does not have any effect to the devices that have already been installed.

Config Paths

ns3::A2A4RsrqHandoverAlgorithm is accessible through the following paths with Config::Set and Config::Connect:

  • "/NodeList/[i]/DeviceList/[i]/$ns3::LteEnbNetDevice/LteHandoverAlgorithm/$ns3::A2A4RsrqHandoverAlgorithm"
  • "/NodeList/[i]/DeviceList/[i]/$ns3::LteNetDevice/$ns3::LteEnbNetDevice/LteHandoverAlgorithm/$ns3::A2A4RsrqHandoverAlgorithm"

Attributes

  • ServingCellThreshold: If the RSRQ of the serving cell is worse than this threshold, neighbour cells are consider for handover. Expressed in quantized range of [0..34] as per Section 9.1.7 of 3GPP TS 36.133.
    • Set with class: ns3::UintegerValue
    • Underlying type: uint8_t 0:34
    • Initial value: 30
    • Flags: constructwriteread
  • NeighbourCellOffset: Minimum offset between the serving and the best neighbour cell to trigger the handover. Expressed in quantized range of [0..34] as per Section 9.1.7 of 3GPP TS 36.133.
    • Set with class: ns3::UintegerValue
    • Underlying type: uint8_t 0:255
    • Initial value: 1
    • Flags: constructwriteread

No TraceSources are defined for this type.
Size of this type is 152 bytes (on a 64-bit architecture).

Definition at line 80 of file a2-a4-rsrq-handover-algorithm.h.

Member Typedef Documentation

◆ MeasurementRow_t

typedef std::map<uint16_t, Ptr<UeMeasure> > ns3::A2A4RsrqHandoverAlgorithm::MeasurementRow_t
private

Measurements reported by a UE for several cells.

The structure is a map indexed by the cell ID.

Definition at line 161 of file a2-a4-rsrq-handover-algorithm.h.

◆ MeasurementTable_t

Measurements reported by several UEs.

The structure is a map indexed by the RNTI of the UE.

Definition at line 167 of file a2-a4-rsrq-handover-algorithm.h.

Constructor & Destructor Documentation

◆ A2A4RsrqHandoverAlgorithm()

ns3::A2A4RsrqHandoverAlgorithm::A2A4RsrqHandoverAlgorithm ( )

Creates an A2-A4-RSRQ handover algorithm instance.

Definition at line 45 of file a2-a4-rsrq-handover-algorithm.cc.

References m_handoverManagementSapProvider, MemberLteHandoverManagementSapProvider< A2A4RsrqHandoverAlgorithm >, and NS_LOG_FUNCTION.

◆ ~A2A4RsrqHandoverAlgorithm()

ns3::A2A4RsrqHandoverAlgorithm::~A2A4RsrqHandoverAlgorithm ( )
virtual

Definition at line 55 of file a2-a4-rsrq-handover-algorithm.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ DoDispose()

void ns3::A2A4RsrqHandoverAlgorithm::DoDispose ( void  )
protectedvirtual

Destructor implementation.

This method is called by Dispose() or by the Object's destructor, whichever comes first.

Subclasses are expected to implement their real destruction code in an overridden version of this method and chain up to their parent's implementation once they are done. i.e, for simplicity, the destructor of every subclass should be empty and its content should be moved to the associated DoDispose() method.

It is safe to call GetObject() from within this method.

Reimplemented from ns3::LteHandoverAlgorithm.

Definition at line 134 of file a2-a4-rsrq-handover-algorithm.cc.

References m_handoverManagementSapProvider, and NS_LOG_FUNCTION.

◆ DoInitialize()

◆ DoReportUeMeas()

void ns3::A2A4RsrqHandoverAlgorithm::DoReportUeMeas ( uint16_t  rnti,
LteRrcSap::MeasResults  measResults 
)
protectedvirtual

Implementation of LteHandoverManagementSapProvider::ReportUeMeas.

Parameters
rntiRadio Network Temporary Identity, an integer identifying the UE where the report originates from
measResultsa single report of one measurement identity

Implements ns3::LteHandoverAlgorithm.

Definition at line 142 of file a2-a4-rsrq-handover-algorithm.cc.

References EvaluateHandover(), ns3::LteRrcSap::MeasResults::haveMeasResultNeighCells, m_a2MeasIds, m_a4MeasIds, m_servingCellThreshold, ns3::LteRrcSap::MeasResults::measId, ns3::LteRrcSap::MeasResults::measResultListEutra, ns3::LteRrcSap::MeasResults::measResultPCell, NS_ASSERT_MSG, NS_LOG_FUNCTION, NS_LOG_WARN, ns3::LteRrcSap::MeasResultPCell::rsrqResult, and UpdateNeighbourMeasurements().

+ Here is the call graph for this function:

◆ EvaluateHandover()

void ns3::A2A4RsrqHandoverAlgorithm::EvaluateHandover ( uint16_t  rnti,
uint8_t  servingCellRsrq 
)
private

Called when Event A2 is detected, then trigger a handover if needed.

Parameters
rntiThe RNTI of the UE who reported the event.
servingCellRsrqThe RSRQ of this cell as reported by the UE.

Definition at line 181 of file a2-a4-rsrq-handover-algorithm.cc.

References IsValidNeighbour(), m_handoverManagementSapUser, m_neighbourCellMeasures, m_neighbourCellOffset, NS_LOG_FUNCTION, NS_LOG_LOGIC, NS_LOG_WARN, and ns3::LteHandoverManagementSapUser::TriggerHandover().

Referenced by DoReportUeMeas().

+ Here is the call graph for this function:
+ Here is the caller graph for this function:

◆ GetLteHandoverManagementSapProvider()

LteHandoverManagementSapProvider * ns3::A2A4RsrqHandoverAlgorithm::GetLteHandoverManagementSapProvider ( )
virtual

Export the "provider" part of the Handover Management SAP interface.

Returns
the reference to the "provider" part of the interface, typically to be kept by an LteEnbRrc instance

Implements ns3::LteHandoverAlgorithm.

Definition at line 97 of file a2-a4-rsrq-handover-algorithm.cc.

References m_handoverManagementSapProvider, and NS_LOG_FUNCTION.

◆ GetTypeId()

TypeId ns3::A2A4RsrqHandoverAlgorithm::GetTypeId ( void  )
static

Get the type ID.

Returns
the object TypeId

Definition at line 62 of file a2-a4-rsrq-handover-algorithm.cc.

References m_neighbourCellOffset, m_servingCellThreshold, ns3::MakeUintegerAccessor(), and ns3::TypeId::SetParent().

+ Here is the call graph for this function:

◆ IsValidNeighbour()

bool ns3::A2A4RsrqHandoverAlgorithm::IsValidNeighbour ( uint16_t  cellId)
private

Determines if a neighbour cell is a valid destination for handover.

Currently always return true.

Parameters
cellIdThe cell ID of the neighbour cell.
Returns
True if the cell is a valid destination for handover.
Todo:
In the future, this function can be expanded to validate whether the neighbour cell is a valid target cell, e.g., taking into account the NRT in ANR and whether it is a CSG cell with closed access.

Definition at line 233 of file a2-a4-rsrq-handover-algorithm.cc.

References NS_LOG_FUNCTION.

Referenced by EvaluateHandover().

+ Here is the caller graph for this function:

◆ SetLteHandoverManagementSapUser()

void ns3::A2A4RsrqHandoverAlgorithm::SetLteHandoverManagementSapUser ( LteHandoverManagementSapUser s)
virtual

Set the "user" part of the Handover Management SAP interface that this handover algorithm instance will interact with.

Parameters
sa reference to the "user" part of the interface, typically a member of an LteEnbRrc instance

Implements ns3::LteHandoverAlgorithm.

Definition at line 89 of file a2-a4-rsrq-handover-algorithm.cc.

References m_handoverManagementSapUser, and NS_LOG_FUNCTION.

◆ UpdateNeighbourMeasurements()

void ns3::A2A4RsrqHandoverAlgorithm::UpdateNeighbourMeasurements ( uint16_t  rnti,
uint16_t  cellId,
uint8_t  rsrq 
)
private

Called when Event A4 is reported, then update the measurements table.

If the RNTI and/or cell ID is not found in the table, a corresponding entry will be created. Only the latest measurements are stored in the table.

Parameters
rntiThe RNTI of the UE who reported the event.
cellIdThe cell ID of the measured cell.
rsrqThe RSRQ of the cell as measured by the UE.

Definition at line 248 of file a2-a4-rsrq-handover-algorithm.cc.

References m_neighbourCellMeasures, NS_ASSERT, and NS_LOG_FUNCTION.

Referenced by DoReportUeMeas().

+ Here is the caller graph for this function:

Friends And Related Function Documentation

◆ MemberLteHandoverManagementSapProvider< A2A4RsrqHandoverAlgorithm >

let the forwarder class access the protected and private members

Definition at line 96 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by A2A4RsrqHandoverAlgorithm().

Member Data Documentation

◆ m_a2MeasIds

std::vector<uint8_t> ns3::A2A4RsrqHandoverAlgorithm::m_a2MeasIds
private

The expected measurement identities for A2 measurements.

Definition at line 141 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by DoInitialize(), and DoReportUeMeas().

◆ m_a4MeasIds

std::vector<uint8_t> ns3::A2A4RsrqHandoverAlgorithm::m_a4MeasIds
private

The expected measurement identities for A4 measurements.

Definition at line 143 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by DoInitialize(), and DoReportUeMeas().

◆ m_handoverManagementSapProvider

LteHandoverManagementSapProvider* ns3::A2A4RsrqHandoverAlgorithm::m_handoverManagementSapProvider
private

Receive API calls from the eNodeB RRC instance.

Definition at line 190 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by A2A4RsrqHandoverAlgorithm(), DoDispose(), and GetLteHandoverManagementSapProvider().

◆ m_handoverManagementSapUser

LteHandoverManagementSapUser* ns3::A2A4RsrqHandoverAlgorithm::m_handoverManagementSapUser
private

Interface to the eNodeB RRC instance.

Definition at line 188 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by DoInitialize(), EvaluateHandover(), and SetLteHandoverManagementSapUser().

◆ m_neighbourCellMeasures

MeasurementTable_t ns3::A2A4RsrqHandoverAlgorithm::m_neighbourCellMeasures
private

Table of measurement reports from all UEs.

Definition at line 170 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by EvaluateHandover(), and UpdateNeighbourMeasurements().

◆ m_neighbourCellOffset

uint8_t ns3::A2A4RsrqHandoverAlgorithm::m_neighbourCellOffset
private

The NeighbourCellOffset attribute.

Minimum offset between the serving and the best neighbour cell to trigger the handover. Expressed in quantized range of [0..34] as per Section 9.1.7 of 3GPP TS 36.133.

Definition at line 185 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by EvaluateHandover(), and GetTypeId().

◆ m_servingCellThreshold

uint8_t ns3::A2A4RsrqHandoverAlgorithm::m_servingCellThreshold
private

The ServingCellThreshold attribute.

If the RSRQ of the serving cell is worse than this threshold, neighbour cells are consider for handover. Expressed in quantized range of [0..34] as per Section 9.1.7 of 3GPP TS 36.133.

Definition at line 178 of file a2-a4-rsrq-handover-algorithm.h.

Referenced by DoInitialize(), DoReportUeMeas(), and GetTypeId().


The documentation for this class was generated from the following files: