Implements a lightweight model for a 4G eNodeB or 5G gNodeB for generating configurable inter-cell interference in the simulated network.

Compared to the eNodeB and gNodeB modules, this module occupies time-frequency resources in both the uplink and downlink bandwidth without simulating the actual transmission or reception of data packets to or from User Equipments (UEs). Therefore, it is significantly more efficient from a simulation speed perspective. To achieve this, it includes a BackgroundTrafficGenerator to customize the level of background traffic to be simulated, a BackgroundCellChannelModel to configure channel parameters, and a BackgroundScheduler that manages the allocation of time-frequency resources based on the traffic generator. Note that this module can generate interference on only one Component Carrier, as configured in the BackgroundScheduler module. To produce interference across multiple carriers, it is possible to use multiple instances of this module, each configured with the desired carrier frequency.

For further details, refer to: G. Nardini, G. Stea, A. Virdis, "Scalable Real-time Emulation of 5G Networks with Simu5G", IEEE Access, vol. 9, pp. 148504-148520, 2021

Usage diagram

The following diagram shows usage relationships between types. Unresolved types are missing from the diagram.

Used in

Name	Type	Description
ExtClientServer_bgCells	network	ExtClientServerExample with background cells instead of external ones: one gNodeB served by a Upf core, a router in front of the Upf, one NrUe, and numBgCells BackgroundCell cells. The router has no simulated peer: the host it talks to, and the applications on the NrUe, are configured in the ini file.
MultiCell_Standalone	network	Two gNodeB cells served by a 5G core: the anchor Upf faces the data network (a router and a server), an intermediate Upf feeds both gNodeBs, and an X2 link joins them. numUe NrUe terminals attach, and numBgCells BackgroundCell cells can be added as interferers.
MultiCell_withSecondaryGnb	network	The two-cell version of SingleCell_withSecondaryGnb: two eNodeB masters, each paired over X2 with its own gNodeB secondary, and a further X2 link between the two masters. Both eNodeBs connect to the EPC PgwStandard, which faces a router and a server; neither gNodeB has a core-network link. numUe NrUe terminals attach, and numBgCells BackgroundCell cells can be added as interferers.
MultiMecHost	network	Two gNodeB cells, each on an intermediate Upf of its own with a MecHost hung off it, so every cell has its own MEC host. Both intermediate Upf nodes meet at the anchor Upf, which carries the Ualcmp and, behind it, the MecOrchestrator. An X2 link joins the two gNodeBs. numUe NrUe terminals attach, and numBgCells BackgroundCell cells can be added as interferers.
MultiMecHost_delay	network	MultiMecHost with the two intermediate Upf nodes linked directly to each other, and with no X2 link between the gNodeBs. The length of that link -- and so its propagation delay -- follows the routersDelay parameter, which makes the distance between the two MEC hosts configurable.
MultiOperator	network	Two operator networks side by side. Each has three gNodeB cells chained by X2, an intermediate Upf that feeds them and carries the operator's MecHost, an anchor Upf, and a Ualcmp with its MecOrchestrator. The two anchor Upf nodes meet at a shared router, the only node the operators have in common. numUe_A and numUe_B NrUe terminals attach to operator A and B respectively, and numBgCells BackgroundCell cells can be added as interferers.
SingleCell_Standalone	network	One gNodeB served by a 5G core: the anchor Upf faces the data network (a router and a server), and an intermediate Upf sits between it and the gNodeB. numUe NrUe terminals attach to the gNodeB, and numBgCells BackgroundCell cells can be added around it as interferers.
SingleCell_Standalone_D2D	network	SingleCell_Standalone with its UEs split into three vectors, so that a configuration can address cellular terminals (ueCell), D2D transmitters (ueD2DTx) and D2D receivers (ueD2DRx) separately. The rest of the topology is the same: one gNodeB behind an intermediate and an anchor Upf, with a router and a server on the data network, plus numBgCells BackgroundCell interferers.
SingleCell_withSecondaryEnb	network	The mirror image of SingleCell_withSecondaryGnb: here the gNodeB is the master node and the eNodeB is its secondary, so the UE is anchored on its NR stack and its LTE stack carries the secondary cell group. All data-plane traffic enters at the gNodeB.
SingleCell_withSecondaryGnb	network	An EN-DC topology: an eNodeB master paired over X2 with a gNodeB secondary. The eNodeB is the only node with a core-network link -- an EPC PgwStandard facing a router and a server -- so all data-plane traffic enters there, and the gNodeB contributes its radio leg alone. numUe NrUe terminals attach to both, and numBgCells BackgroundCell cells can be added as interferers.
UrbanNetwork	network	(no description)

Properties

Name	Value	Description
display	i=device/antennatower;bgb=430,163

Unassigned submodule parameters

Name	Type	Default value	Description
mobility.subjectModule	string	"^"	module path which determines the subject module, the motion of which this mobility model describes, the default value is the parent module
mobility.coordinateSystemModule	string	""	module path of the geographic coordinate system module
mobility.displayStringTextFormat	string	"p: %p\nv: %v"	format string for the mobility module's display string text
mobility.updateDisplayString	bool	true	enables continuous update of the subject module's position via modifying its display string
mobility.constraintAreaMinX	double	-inf m	min x position of the constraint area, unconstrained by default (negative infinity)
mobility.constraintAreaMinY	double	-inf m	min y position of the constraint area, unconstrained by default (negative infinity)
mobility.constraintAreaMinZ	double	-inf m	min z position of the constraint area, unconstrained by default (negative infinity)
mobility.constraintAreaMaxX	double	inf m	max x position of the constraint area, unconstrained by default (positive infinity)
mobility.constraintAreaMaxY	double	inf m	max y position of the constraint area, unconstrained by default (positive infinity)
mobility.constraintAreaMaxZ	double	inf m	max z position of the constraint area, unconstrained by default (positive infinity)
mobility.initialX	double	uniform(this.constraintAreaMinX, this.constraintAreaMaxX)
mobility.initialY	double	uniform(this.constraintAreaMinY, this.constraintAreaMaxY)
mobility.initialZ	double	nanToZero(uniform(this.constraintAreaMinZ, this.constraintAreaMaxZ))
mobility.initialLatitude	double	nan deg
mobility.initialLongitude	double	nan deg
mobility.initialAltitude	double	0m
mobility.initialHeading	double	0deg
mobility.initialElevation	double	0deg
mobility.initialBank	double	0deg
mobility.initFromDisplayString	bool	true	enables one time initialization from the subject module's display string
mobility.updateFromDisplayString	bool	true	enables continuous update from the subject module's display string for dragging and rotating it
bgChannelModel.binderModule	string	"binder"	Module references
bgChannelModel.shadowing	bool	true	Enable/disable shadowing
bgChannelModel.scenario	string	"URBAN_MACROCELL"	Path loss scenario, in ITU terminology
bgChannelModel.nodebHeight	double	25m	eNodeB height
bgChannelModel.buildingHeight	double	20m	Building height
bgChannelModel.insideBuilding	bool	false	Determines if the UE is inside a building
bgChannelModel.streetWidth	double	20m	TODO width
bgChannelModel.ueHeight	double	1.5m
bgChannelModel.tolerateMaxDistViolation	bool	false
bgChannelModel.correlationDistance	double	50m
bgChannelModel.antennaGainUe	double	0dBi	Antenna gain of the UE, relative to an isotropic antenna
bgChannelModel.antennGainEnB	double	18dBi	Antenna gain of the eNodeB
bgChannelModel.antennGainMicro	double	5dBi	Antenna gain of the micro node
bgChannelModel.thermalNoise	double	-104.5dBm	Thermal noise for 10 MHz of bandwidth
bgChannelModel.ueNoiseFigure	double	7dBm	UE noise figure
bgChannelModel.bsNoiseFigure	double	5dBm	eNodeB noise figure
bgChannelModel.cableLoss	double	2dB	Cable loss
bgChannelModel.dynamicLos	bool	false	Whether LOS/NLOS is drawn per link from the scenario's LOS probability; when false, it is fixed to fixedLos
bgChannelModel.fixedLos	bool	false	LOS state of every link when dynamicLos is false: true = LOS, false = NLOS
bgChannelModel.fading	bool	true	Enable/disable fading
bgChannelModel.fadingType	string	"JAKES"	Fading type (JAKES or RAYLEIGH)
bgChannelModel.numFadingPaths	int	6	If Jakes fading, this parameter specifies the number of paths (tap channel)
bgChannelModel.delayRms	double	363ns
bgChannelModel.bgCellInterference	bool	true	Whether interference from the other background cells is included in the SINR, in both UL and DL
bgChannelModel.downlinkInterference	bool	true	Whether interference from other base stations is included in the DL SINR
bgChannelModel.uplinkInterference	bool	true	Whether interference from the UEs of other cells is included in the UL SINR
bgScheduler.binderModule	string	"binder"
bgScheduler.channelModelModule	string	"^.bgChannelModel"
bgScheduler.txPower	double	46dBm	Transmission power
bgScheduler.txDirection	string	"OMNI"	Transmission direction
bgScheduler.txAngle	double	0deg	Transmission angle
bgScheduler.isNr	bool	false	Flag to indicate whether this is a NR base station
bgScheduler.numerologyIndex	int	0	Operating carrier
bgScheduler.carrierFrequency	double	2GHz	Operating carrier
bgScheduler.numBands	int	6	Carrier bandwidth

Source code

//
// Implements a lightweight model for a 4G eNodeB or 5G gNodeB for generating
// configurable inter-cell interference in the simulated network.
//
// Compared to the ~eNodeB and ~gNodeB modules, this module occupies time-frequency
// resources in both the uplink and downlink bandwidth without simulating the actual
// transmission or reception of data packets to or from User Equipments (UEs).
// Therefore, it is significantly more efficient from a simulation speed perspective.
// To achieve this, it includes a ~BackgroundTrafficGenerator to customize the level of background
// traffic to be simulated, a ~BackgroundCellChannelModel to configure channel parameters, and a
// ~BackgroundScheduler that manages the allocation of time-frequency resources based on the traffic
// generator.
// Note that this module can generate interference on only one Component Carrier, as configured
// in the ~BackgroundScheduler module. To produce interference across multiple carriers, it is
// possible to use multiple instances of this module, each configured with the desired carrier frequency.
//
// For further details, refer to:
//     G. Nardini, G. Stea, A. Virdis, "Scalable Real-time Emulation of 5G Networks with Simu5G",
//     IEEE Access, vol. 9, pp. 148504-148520, 2021
//
module BackgroundCell
{
    parameters:
        @display("i=device/antennatower;bgb=430,163");

    submodules:
        // mobility module for the background base station
        mobility: StationaryMobility {
            @display("p=100,38;is=s");
        }

        // channel model for the background cell
        bgChannelModel: BackgroundCellChannelModel {
            @display("p=100,105;is=s");
        }

        // perform the scheduling for the BackgroundCell
        bgScheduler: BackgroundScheduler {
            @display("p=222,38,row");
            trafficManagerModule = "^.bgTrafficGenerator.manager";
        }

        // traffic generator for the background UEs within the BackgroundCell
        bgTrafficGenerator: BackgroundTrafficGenerator {
            @display("p=347,38,row");
            manager.typename = default("BackgroundCellTrafficManager");
        }
}

File: src/simu5g/nodes/BackgroundCell.ned

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