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What's New in Simu5G

v1.6.0 (2026-07-31)

This release adds a standards-compliant NR RLC to Simu5G. RLC Unacknowledged Mode and Acknowledged Mode per TS 38.322 contributed by Esteban Egea Lopez have been integrated into the mainline and are now the default on NR bearers. The RLC entity modules were restructured into shared bases with LTE and NR concrete implementations. The previously incomplete LTE RLC AM was reimplemented per TS 36.322 on the same architecture. Radio link failure detection with RRC re-establishment was added. This release, like all releases since v1.3.1, was developed by Andras Varga and the OMNeT++ core team.

Tested with INET-4.5.4 and OMNeT++ 6.3, compatible with INET-4.6.0 and OMNeT++ 6.1 through 6.4.

NR RLC (TS 38.322)

Simu5G's RLC layer so far implemented only the LTE wire format (TS 36.322: FI framing with concatenation, one sequence number per PDU), and NR bearers used it as well. This release adds a faithful NR RLC:

  • Unacknowledged Mode: NrRlcUmTxEntity/NrRlcUmRxEntity perform SI + byte-offset (SO) segmentation without concatenation -- one SDU or SDU segment per PDU, one sequence number per SDU, NrRlcUmDataPdu on the wire. Reassembly is byte-coverage based (RlcUmReceptionBuffer) over an SDU-SN window with t-Reassembly. The SN field length is selectable (6 or 12 bits).

  • Acknowledged Mode: NrRlcAmTxEntity/NrRlcAmRxEntity perform SO segmentation with re-segmentation on retransmission (via RlcRetransmissionBuffer), pollByte/pollPDU-driven status polling with t-PollRetransmit, and reassembly with t-Reassembly and t-StatusProhibit, using the NrRlcAmDataPdu/NrRlcAmStatusPdu formats over a 12- or 18-bit sequence number window.

  • NR bearers use the NR RLC by default: BearerManagement gained the nrRlcUmEntityModuleType and nrRlcAmEntityModuleType parameters (default: the new NrRlcUmEntity/NrRlcAmEntity compound modules), and selects them for every bearer that has an NR node at either end; LTE bearers keep the lteRlc* ones. RLC framing is a function of the RAT rather than a free choice, so there is no LTE/NR mix; TM, being transparent, is identical for both RATs and has no NR variant.

This changes results in every NR simulation: the NR wire format has different per-PDU header sizes and a different segmentation/reassembly discipline than LTE FI framing, so packet timing, delay and throughput shift. (The MAC and scheduler groundwork for it -- one PDU per SDU or segment, several RLC PDUs multiplexed into one grant, exact octet-aligned header sizing -- shipped in v1.5.1 and is only now actually exercised.) A configuration that needs the previous behavior can point nrRlcUmEntityModuleType and nrRlcAmEntityModuleType back at the LteRlcUmEntity/LteRlcAmEntity compounds.

The NR RLC UM and AM implementations were contributed by Esteban Egea Lopez (Universidad Politécnica de Cartagena). The code was originally published as the "Simu5G-1.3.1 RLC-AM" special release and rebased onto several Simu5G versions since; adapting it to the current RLC architecture was done by Attila Török (OpenSim Ltd).

RLC entity modules restructured

The RLC entity module and class names were made consistent with their surroundings (RlcMux, RlcTxEntityBase, ...), the AM "Queue" names were normalized to "Entity", and each mode's two variants were factored into a shared base with LTE and NR concrete subclasses (RlcUmTxEntityBase with LteRlcUmTxEntity/NrRlcUmTxEntity, and likewise for the other three). The common shell -- MAC plumbing, D2D mode-switch machinery, UL burst-throughput accounting -- lives in the base; only buffering, PDU build, reassembly, window and timer logic is mode-specific. The renames:

  UmTxEntity  ->  LteRlcUmTxEntity      TmTxEntity  ->  RlcTmTxEntity
  UmRxEntity  ->  LteRlcUmRxEntity      TmRxEntity  ->  RlcTmRxEntity
  AmTxQueue   ->  LteRlcAmTxEntity
  AmRxQueue   ->  LteRlcAmRxEntity

Configurations that name these NED types explicitly need to be updated. The NrRlcUmEntity and NrRlcAmEntity compounds are subclasses of RlcUmEntityBase and RlcAmEntityBase that bind their two sides to the NR concrete entities with tx.typename/rx.typename.

LTE RLC AM reimplemented per TS 36.322

Simu5G's original LTE RLC AM was derived from UMTS RLC (TS 25.322), it was incomplete, and no simulation configuration used it. What it implemented was not TS 36.322 compliant: the wire format was per-SDU fragmentation with a sequence number per fragment (no concatenation, no FI/LI, no poll bit), retransmission was driven by per-PDU timeouts that resent without any NACK, a PDU exhausting its retransmissions was silently discarded with no radio link failure indication, and status reporting was periodic rather than event-driven.

It has been reimplemented from scratch on the architecture of the NR AM entity, whose TS 38.322 ARQ skeleton TS 36.322 shares; only the framing is LTE-specific:

  • One AMD PDU per MAC grant, built by concatenating queued SDUs and SDU fragments (FI framing, on the same PDU model the LTE UM entity uses). The built PDU, retained in the 512-entry (10-bit SN) transmission window, is the unit of ARQ.
  • NACK-driven retransmission with the ACK_SN + NACK-list STATUS PDU (the same StatusPduData structure the NR AM uses, including SOstart/SOend byte ranges), re-segmenting a retained PDU into AMD PDU segments when the grant is smaller than the PDU.
  • pollPDU/pollByte/t-PollRetransmit polling, t-Reordering and t-StatusProhibit at the receiver, and radio link failure at maxRtxThreshold retransmissions, wired to the same BearerManagement teardown and RRC re-establishment as the NR AM.

Since no configuration could use the old LTE AM, this does not affect existing simulation results.

Selecting RLC AM

Acknowledged Mode is now usable on both RATs, but nothing selects it by default: every bearer stays in the mode it had before, so existing simulations are unaffected. Two mechanisms choose the mode of a bearer, depending on whether SDAP is in the stack.

Without SDAP, Ip2Nic classifies each packet into a traffic class by packet name (VoIP* -> conversational, gaming* -> interactive, VoDPacket* -> streaming, anything else -> background) and maps the class to an RLC mode with its conversationalRlc, streamingRlc, interactiveRlc and backgroundRlc parameters. They accept "TM", "UM" and "AM", and all four default to "UM" (which is the pre-v1.6.0 behavior, kept for backward compatibility).

With SDAP in the stack (hasSdap = true on the NR NIC), Ip2Nic skips traffic classification entirely and the mode becomes a property of the DRB: every entry of NrSdap.drbConfig takes an optional rlcType field, again one of "AM", "UM" and "TM", and again defaulting to "UM". For example:

  *.gnb.cellularNic.hasSdap = true
  *.gnb.cellularNic.sdap.drbConfig = [
      {"drb": 0, "ue": 2049, "qfiList": [1, 2], "rlcType": "UM"},
      {"drb": 1, "ue": 2049, "qfiList": [3, 4], "rlcType": "AM"}]

Either way, both ends of a bearer must be configured with the same mode: each node builds its own RLC entity from its own configuration, so a mismatch leaves an AM entity facing a UM one. With Ip2Nic, this can be ensured by using **. wildcards; with SDAP, the UE's drbConfig entry for a DRB and the gNB's entry for the same DRB have to agree on rlcType.

Which entity type then implements the mode follows from the RAT, as described above: an AM bearer with an NR node at either end runs the NrRlcAmEntity compound, an LTE one LteRlcAmEntity. TM is available on both, and is the same entity for both.

RLC validation scenarios

The new simulations/nr/rlc and simulations/lte/rlc directories hold protocol-validation scenarios for the two RLC implementations: a single UE over LteDummyChannelModel -- which replaces propagation modelling with a configurable per-direction packet error rate, so with independent HARQ attempts the residual loss RLC sees is exactly perDl^(maxHarqRtx+1) -- with deterministic CBR traffic and the loss process on its own RNG. The scenarios sweep the error rate (AM-Lossy, with UM-Lossy as the no-ARQ contrast), force segmentation and re-segmentation on retransmission (AM-Segmentation), concatenation on LTE (AM-Concatenation), a transmission-window stall that must recover (AM-WindowStall), and a scripted mid-run coverage loss that must end in a radio link failure (AM-RLF) or in RRC re-establishment with the flow resuming (AM-RLF-Reestablish). Three scenarios cover the common usage patterns beyond a lossy downlink: AM-Lossy-UL (both RATs) runs the flow uplink, through the UE MAC's strict grant accounting; TCP-AM carries a TCP transfer over the lossy bearer, its acknowledgement stream putting data through the reverse direction of the same bearer; and lte/test_handover VoIP-AM-Handover runs bidirectional VoIP over AM with the UEs moving through handovers.

Measured on both RATs: every AM configuration delivers every offered SDU at every loss rate in the sweep, uplink and downlink -- the AM guarantee -- while UM loses the predicted residual fraction, and the per-attempt HARQ error rate matches the configured error rate throughout. TCP makes steady progress over a downlink losing half its transmission attempts, and the handover scenario completes with zero application-level frame loss and no entities left behind at the old cell.

Defects found in the NR AM implementation found using these scenarios were fixed.

Radio link failure and RRC re-establishment

The RLC AM transmitters declare a radio link failure when a PDU exceeds maxRtxThreshold retransmissions (TS 38.322 5.3.2 / TS 36.322 5.2.1). This is now wired to a full teardown of the link:

  • BearerManagement::scheduleRadioLinkFailure() defers the teardown to a safe execution context (so that entity modules are never deleted from inside packet processing), then releases the link at both ends -- reaching the peer's BearerManagement through the Binder -- deleting the bearer's MAC (deleteQueuesRadioLinkFailure(), which also drops the node's in-flight HARQ feedback), RLC and PDCP state.

  • Ip2Nic gained releaseUe()/resumeUe(), and drops a released peer's DL and UL packets for as long as its context is released, modeling the RRC UE Context Release. Without this, the application kept pushing packets at torn-down entities, which crashed; handover does not have this problem only because it redirects the traffic to a new cell.

  • RRC re-establishment (TS 38.331 5.3.7) is modeled by its timers, the way handover signaling already is: BearerManagement.t311 (cell selection) and t301 (request to complete). When t301 expires, the peer is un-released and its bearer re-establishes on demand. The default t311 = 0s disables re-establishment, that is, a radio link failure releases the UE to idle.

This is inert in simulations that do not use RLC AM, as only the AM entities detect radio link failures.

RLC statistics recorded on the bearer entities

The per-bearer RLC statistics -- rlcDelay*, rlcThroughput*, rlcPduDelay*, rlcPduThroughput*, rlcPacketLoss* and their D2D variants -- are now recorded on the RLC entity module of the bearer that produced them, instead of on an RlcMux. Configurations and analysis files that refer to these results by module path need to be updated, for example from

  SingleCell.ue[0].cellularNic.nrRlcMux.rlcDelayDl:mean

to the bearer entity that measured it, such as

  SingleCell.ue[0].cellularNic.nrRlc-um-1-1.rx.rlcDelayDl:mean

The old arrangement dates from when RLC was a single module per network interface, with the per-connection entities being plain C++ objects inside it: there was no per-bearer module to record on, so a receiving entity reached the other node's mux through the Binder and emitted the sample there -- an uplink measurement taken at the gNB was recorded as a result of the UE. Since v1.5.0 the entities are modules in their own right, one per peer and radio bearer, so each sample is now recorded where it is produced. Results for one UE across its bearers are obtained by aggregating over its entity modules in the analysis tool.

The cell-level statistics (rlcCellThroughput*, rlcCellPacketLoss*) were removed rather than moved. The cell throughput was computed from a C++ static byte counter -- one counter for the entire simulation, not one per cell -- so in any scenario with more than one cell, every serving node reported approximately the network-wide total as its own cell throughput. (In lte/multicell, both eNBs report the global figure; the true per-cell values are about half of what was recorded.) The statistic was correct only in single-cell scenarios, where it equals the sum of the per-bearer rlcThroughput* results, which is how it can be obtained now.

The MAC layer's macCellThroughput* statistics (including the D2D variant, which shared the same counter and thus mixed D2D and cellular bytes) had the identical defect and were removed for the same reason; the per-UE macThroughput* results remain. macCellPacketLoss*, which is computed per-cell correctly, is kept.

Two side effects are worth noting. rlcPacketLoss* was emitted onto a module that did not declare it, so it was never recorded at all; it now is. And per-bearer results that used to be merged into one mux are visible separately per bearer, which is what makes the two legs of a Dual Connectivity split bearer individually measurable.

PDCP mux renamed and refactored

UpperMux was renamed to PdcpMux: the old name said where the module sits relative to the PDCP entities rather than which layer it belongs to, and did not match its RLC counterpart RlcMux (the submodule was already named pdcpMux). Like RlcMux in v1.5.2, it now maps DRBs to toTxEntity gate indices instead of TX entity pointers, so dispatch is plain multiplexing.

Both muxes became replaceable submodules, with the new IPdcpMux and IRlcMux module interfaces. Replaceability is partial: BearerManagement creates and wires the per-bearer gates and registers the routing tables through the C++ classes, so an implementation has to subclass PdcpMux or RlcMux; what the interface buys is type selection from NED and ini.

The NR-leg flag moved off PdcpMux, which never read it, onto its only reader, Ip2Nic: cellularNic.pdcpMux.isNR is now cellularNic.ip2nic.isNr, spelled like the same flag on LteMacUe, LtePhyUe and HandoverController. Configurations that set it need to be updated. BaseStationStatsCollector also lost its pdcpModule parameter, which was unread and pointed at a module the v1.5.0 PDCP flattening deleted.

Other

  • RLC statistics on NR bearers: the NR RLC entities did not emit the per-bearer delay and throughput statistics that their LTE counterparts do, so those results were empty in NR simulations from the moment the NR RLC became the default on NR bearers. They are emitted now. NrRlcAmRxEntity also emits rxWindowOccupation, which was declared but never emitted; the NR UM transmitter's requestedPDUSize/sentPDUSize statistics were renamed to requestedPduSize/sentPduSize, and it gained the receivedPacketFromUpperLayer/sentPacketToLowerLayer counters.

  • LteDummyChannelModel made usable: the class had no NED type (so it could not be instantiated) and hardcoded error rates. It now has one, with per / perDl / perUl / perD2D and harqReduction parameters -- the per-direction rates volatile, so a coverage loss can be scripted as a function of time -- turning it into a controlled loss source for protocol validation: with harqReduction = 1 the residual loss RLC sees is exactly per^(maxHarqRtx+1). It also reports SINR/RSRP on every band; the single-element vector it used to return broke the AMC.

  • MEC RNI: PacketFlowObserver now also tracks NR SO PDUs, which carry no per-PDU RLC sequence number, by keying the per-SDU tracking on the PDCP sequence number instead. The reported delay is exact for the common unsegmented case; an SDU segmented across several MAC PDUs is accounted as delivered on the acknowledgement of its first segment.

  • D2D: D2D bearers run on the NR RLC as well; draining of the mode-switch holding buffer now takes place in the owning entity's context.

  • Module references: the RLC-to-RRC and RRC-to-Ip2Nic lookups became NED module-path parameters (RlcMux.bearerManagementModule, BearerManagement.ip2nicModule), continuing the ModuleRefByPar conversion.

  • Simulations: nr/standalone gained the VoIP-DL-AM, VoIP-DL-AM-Lossy, VoIP-UL-AM, VoIP-DL-UM-NR and VoIP-UL-UM-NR configurations, and lte/demo the VoIP-AM configuration, exercising the AM and the NR RLC paths.

  • Fingerprint tests: the five new configurations above were added to the suite, together with the RLC validation scenarios of simulations/nr/rlc and simulations/lte/rlc and the VoIP-AM-Handover configuration of lte/test_handover (157 configurations in total), and the rows were re-recorded for the NR RLC default and the statistics changes.

  • Documentation: the RLC entity documentation comments were retargeted at the compound modules that actually bind them -- several still referred to per-side rlcUm{Tx,Rx}EntityModuleType parameters, which v1.5.1 replaced with selection on the per-bearer compound -- and the RlcUmEntityBase / RlcAmEntityBase comments now name both of their concrete subclasses.

  • Source housekeeping: file headers were brought in line -- the contributed NR RLC sources now carry the standard Simu5G header naming their author instead of an LGPL blurb, files that had no header got one, and new files that had inherited the header of the file they were derived from now name their actual author. The redundant @class line was dropped from the C++ class comments, and IRlcAmEntities.ned was split into IRlcAmTxEntity.ned and IRlcAmRxEntity.ned, one interface per file. The interfaces themselves, and all type names, are unchanged.

v1.5.2 (2026-07-30)

This release corrects the names of the per-bearer PDCP and RLC entity modules that v1.5.0 and v1.5.1 introduced, before more code comes to depend on them. It changes names only: no behavior changes, and no simulation results change. It also refactors RlcMux.

Tested with INET-4.5.4 and OMNeT++ 6.3, compatible with INET-4.6.0 and OMNeT++ 6.1 through 6.4.

PDCP and RLC entity module names made consistent

The PDCP entity modules and their module interfaces were renamed so that the TX/RX role follows the layer name, as it does in RLC and in their own C++ base classes (PdcpTxEntityBase, PdcpRxEntityBase):

  LteTxPdcpEntity  ->  LtePdcpTxEntity      ITxPdcpEntity  ->  IPdcpTxEntity
  LteRxPdcpEntity  ->  LtePdcpRxEntity      IRxPdcpEntity  ->  IPdcpRxEntity
  NrTxPdcpEntity   ->  NrPdcpTxEntity
  NrRxPdcpEntity   ->  NrPdcpRxEntity

The per-bearer compound modules were restructured so that an explicit LTE concrete type stands beside the NR one, instead of the base type doubling as the LTE type. PdcpEntity, RlcUmEntity and RlcAmEntity became PdcpEntityBase, RlcUmEntityBase and RlcAmEntityBase, which bind no entity types and are therefore not instantiable on their own; the instantiable types are their subclasses, which bind their two sides with tx.typename/rx.typename:

  PdcpEntity   ->  PdcpEntityBase   + new LtePdcpEntity
  RlcUmEntity  ->  RlcUmEntityBase  + new LteRlcUmEntity
  RlcAmEntity  ->  RlcAmEntityBase  + new LteRlcAmEntity

NrPdcpEntity is now a subclass of PdcpEntityBase. A mixed entity (e.g. an EN-DC master eNB, which runs an NR TX side with an LTE RX side) still overrides just tx.typename or rx.typename.

BearerManagement's parameters that select the RLC entity types were renamed so that the LTE ones are marked as explicitly as their coming NR counterparts: rlcUmEntityModuleType -> lteRlcUmEntityModuleType and rlcAmEntityModuleType -> lteRlcAmEntityModuleType. Its pdcpEntityModuleType parameter keeps its name -- it is a single per-node selector, and it holds an NR type at every gNB -- and now defaults to LtePdcpEntity. RlcTmEntity and rlcTmEntityModuleType are unchanged: TM is transparent and identical for both RATs, so it has a single entity type.

Configurations that name any of these NED types explicitly need to be updated.

RlcMux refactoring

RlcMux now maps DRBs to gate indices, not RX entity pointers. Its internal table now holds the index of the toRxEntity gate serving each DRB instead of a pointer to the RX entity, so PDU dispatch is plain multiplexing: send() on the gate index, with no entity involved. It used to make a round trip -- look up the entity, then ask it for its gate and walk back to our own gate.

v1.5.1 (2026-07-28)

This release continues the architectural overhaul of Simu5G, focusing on the PDCP and RLC layers: per-bearer protocol entities are now packaged into compound modules, DRBs are established as bidirectional (duplex) bearers, and the Dual Connectivity split-bearer data path was restructured.

Tested with INET-4.5.4 and OMNeT++ 6.3, compatible with INET-4.6.0 and OMNeT++ 6.1 through 6.4.

Per-bearer PDCP and RLC compound entity modules

v1.5.0 transformed the PDCP and RLC layers into dynamically created per-bearer TX/RX entity modules. This release packages the two sides of each bearer into one compound module per bearer, following the 3GPP model of one PDCP/RLC entity per bearer (for RLC AM explicitly with a transmitting and a receiving side):

  • RLC: Each bearer's TX and RX entities now live in an RlcTmEntity, RlcUmEntity or RlcAmEntity compound module. In AM, the internal control paths are now explicit gate connections between the RX and TX submodules, replacing C++ registry-lookup calls between the two simple modules: feedbackOut -> feedbackIn carries the STATUS PDUs received from the peer into the TX side's ARQ, and statusOut -> statusIn hands the locally generated status reports to the TX side for transmission.

  • PDCP: Each bearer's TX and RX entities now live in a PdcpEntity compound module. Variants are subclasses overriding the entity typenames (NrPdcpEntity); a mixed entity (e.g. an EN-DC master eNB, which runs an NR TX side with an LTE RX side) overrides just tx.typename or rx.typename.

  • PdcpRelayEntity: At a Dual Connectivity secondary node, which only tunnels already-processed PDUs between the master (over X2) and its own RLC, the two per-bearer bypass modules were packaged into a PdcpRelayEntity compound module, which stands in place of the bearer's PDCP entity; BypassTxPdcpEntity/BypassRxPdcpEntity were renamed to PdcpDownlinkRelay/PdcpUplinkRelay.

  • New module interfaces (ITxPdcpEntity, IRxPdcpEntity, IRlcTxEntity, IRlcRxEntity, IRlcAmTxEntity, IRlcAmRxEntity) make the entity implementations replaceable: every compound binds its two sides with the standard tx.typename/rx.typename submodule typename assignment, which a configuration or a subclass of the compound can override. The ten per-side entity-type parameters of BearerManagement were consolidated into five per-compound ones (pdcpEntityModuleType, pdcpRelayEntityModuleType, rlcTm/Um/AmEntityModuleType).

DRBs established as duplex (bidirectional) bearers

Per TS 38.331, a DRB is bidirectional; Simu5G so far established each direction as an independent unidirectional bearer with its own locally-assigned DRB id. RLC AM fundamentally needs the reverse path of the same bearer for its STATUS PDUs, which the old model could only provide via on-demand reverse entities created from inside packet processing. Now:

  • Binder::establishDataConnection() (renamed from establishUnidirectionalDataConnection()) creates both directions of a unicast bearer at once; multicast bearers remain unidirectional.

  • DRB ids are allocated by the Binder with a counter per node pair, so the two ends of a bearer see the same DRB id, and DRB ids are peer-scoped (per-UE identities, as in the spec) rather than node-unique.

  • Reverse application traffic resolves to the reverse leg of the existing bearer instead of allocating a second bearer.

This may change results in simulations where request and response flows between the same node pair previously used two separate bearers: they now share one duplex bearer, which changes logical channel ids and can change scheduling order under contention.

Dual Connectivity split-bearer data path restructured

A DC split bearer is one PDCP entity -- one sequence number space -- whose PDUs are steered per-packet across two RLC legs. The PdcpEntity compound now reflects this: its lower boundary is a legOut[]/legIn[] gate vector. A plain bearer has one leg, and the TX/RX entities connect straight to it; a split bearer routes the TX side through a DcPdcpLegSplitter (per-PDU leg dispatch, per-leg DC id mapping and statistics) and merges both legs through a PdcpLegJoiner into the single RX entity, whose one reordering window restores sequence order across the legs. The per-packet leg steering policy itself remains in TechnologyDecision; the splitter only executes it.

MAC prepared for NR RLC framing

The MAC and the schedulers can now accommodate an RLC that emits one SDU or segment per PDU without concatenation (the NR model of TS 38.322), in addition to LTE's single concatenated PDU per grant: for such flows, the schedulers plan one PDU per SDU/segment to fill the grant, the MAC issues one SDU request per planned PDU and multiplexes them into the MAC PDU, and exact per-PDU RLC header sizes are computed (octet-aligned, per SN length and segment state). This is inert by default (soFraming=false keeps the LTE path) and is groundwork for an upcoming standards-compliant NR RLC implementation.

Beacon emission control at the eNB/gNB

  • Beacon broadcasting was decoupled from enableHandover: the new enableBeacons parameter (default: enableHandover) controls it, so that radio link monitoring can later work without handover enabled. enableHandover=true now requires beacons to actually flow.

  • A non-positive beaconInterval is now an initialization error instead of silently disabling beacons; beacons are switched off with enableBeacons=false.

Module architecture improvements

  • isNr as parameter: LteMacUe, LtePhyUe and LteDlFeedbackGenerator no longer determine whether they are the NR leg of the UE by string-matching their own module name ("nrMac", "nrPhy", "nrDlFbGen"); they now have a bool isNr parameter, set by NrNicUe.

  • Parametrized module references: Hardcoded getSubmodule() walks inside the NIC were replaced with NED module-path parameters (11 new parameters across BearerManagement, HandoverController, DcMux, LteMacEnb and TechnologyDecision), and foreign-node lookups now go through Binder helper methods.

  • IHandoverPacketHolder: The hoManagerOut gate was added to the module interface, so that custom holder implementations can be substituted (contributed by Mohamed Seliem).

Bug fixes

  • Crash on interleaved Dual Connectivity leg handovers: Fixed a long-standing crash (also present in v1.4.3..v1.4.5) triggered when the LTE leg of an NR UE hands over while its NR leg is detached: per-UE state provisioned at the old master's secondary gNB was left orphaned, and re-establishment collided with the leftovers when the UE later returned. Handover cleanup now also covers the old serving node's secondary. In addition, PDCP entity teardown at NR UEs is now keyed by peer node, so an NR-leg detach no longer deletes the LTE leg's entities as well.

  • MAC: macSduRequest() no longer underflows when the scheduler allocates a grant smaller than the MAC header, which surfaced as a misleading "configured queueSize too low" error with many DRBs under QOS_PF contention (contributed by Mohamed Seliem).

  • NrPhyUe: D2D DATA frames arriving while the UE is detached during handover are now dropped, as LtePhyUeD2D already did, instead of crashing on already-deleted HARQ buffers.

  • HandoverController: Removed a redundant second detach/attach of the D2D direction on the AMC during NR UE handover.

  • LtePhyEnb: Corrected copy-pasted class names in requestFeedback() error messages.

Other

  • Fingerprint tests: The simulation-time intervals of configurations involving events like handover or D2D mode switching were extended so that the fingerprint window actually covers those events, and fingerprints were re-recorded for the architectural changes above.

v1.5.0 (2026-07-13)

This release continues the architectural overhaul of Simu5G. Major themes include consolidating Control Plane functions under the RRC module, adding QoS support via DRBs and the SDAP protocol, restructuring Ip2Nic and other modules for cleaner architecture, and improving type safety throughout the codebase.

Tested with INET-4.5.4 and OMNeT++ 6.3, compatible with INET-4.6.0 and OMNeT++ 6.1 through 6.4.

More explicit Control Plane modeling

Continuing the direction set in v1.4.3, code fragments that implement pieces of the 3GPP Control Plane have been identified throughout the codebase and collected under the Rrc module. Rrc is now a compound module with the following submodules:

  • BearerManagement: The former simple Rrc module, renamed and extended. It now owns the lifecycle (creation, deletion, lookup) of all PDCP and RLC entities. Previously, entity management was scattered across the monolithic PDCP module and the LteRlcUm/LteRlcAm modules.

  • Registration: Node registration and deregistration logic, previously embedded in Ip2Nic, was moved here.

  • HandoverController: Handover decision and execution logic was extracted from LtePhyUe into this new module. This is architecturally more correct, as handover is an RRC function, not PHY. The internal "handover packet" misnomer was corrected to "beacon" (HANDOVERPKT -> BEACONPKT, broadcastMessageInterval -> beaconInterval). Several parameters were exposed as NED parameters (hysteresisFactor, handoverDetachmentTime, isNr).

  • D2DModeController: D2D mode selection was moved here from the former stack/d2dModeSelection/ directory, and D2D peer tracking from LteRlcUmD2D.

QoS support: SDAP, DRBs and per-bearer PDCP/RLC entities

QoS (Quality of Service) support was added through Data Radio Bearers (DRBs) and the SDAP (Service Data Adaptation Protocol) layer, which is part of the 5G NR protocol stack. The code is based on a contribution by Mohamed Seliem (University College Cork); see releases v1.4.1-sdap and v1.4.1-sdap-2 for details. In this release, the code was substantially reworked and integrated into the main codebase.

In accordance with the 3GPP architecture, the PDCP and RLC layers were transformed so that they purely consist of per-DRB entities, created and configured by BearerManagement (RRC). Each DRB has dedicated PDCP TX/RX and RLC TX/RX entity modules, wired directly to each other via per-bearer gate connections.

Details:

  • SDAP protocol layer: An SDAP implementation was added, providing QFI-to-DRB routing with a JSON-configured DrbTable. The SDAP layer is optional in NR NICs (enabled via hasSdap=true).

  • QFI propagation via GTP-U: QFI is set by the application via DSCP, picked up by TrafficFlowFilter/UPF, carried in the GTP-U protocol header (mirroring the 3GPP PDU Session Container extension header), and extracted by the gNB for SDAP routing.

  • QoS-aware proportional fairness scheduler: A QoSAwareScheduler was added to MAC, supporting QFI-based scheduling with configurable weight constants. Enable with LteMacEnb.schedulingDisciplineDl/Ul = "QOS_PF".

  • DRB configuration in JSON: DRB configuration is split between SDAP (sdap.drbConfig for QFI-to-DRB routing) and MAC (mac.drbQosConfig for QoS scheduler parameters), both in JSON format.

  • Non-IP PDU session support: SDAP was generalized for non-IP PDU session types, with PduSessionType enum and upperProtocol in DRB configuration.

  • PDCP refactored into per-bearer entities: The former monolithic PDCP module (which had six subclass variants for LTE/NR × UE/eNB/D2D) was replaced with per-bearer PdcpTxEntity and PdcpRxEntity modules, plus PdcpMux for upper-layer routing and DcMux for Dual Connectivity X2 forwarding. Bypass entities handle the DC secondary leg. Entities communicate via OMNeT++ gates, not C++ method calls.

  • RLC refactored into per-bearer entities: The former LteRlc compound module (containing LteRlcUm/LteRlcUmD2D, LteRlcAm, LteRlcTm) was replaced with per-bearer TX/RX entity modules for all three RLC modes (UM, AM, TM), plus RlcMux for MAC↔entity routing.

  • PDCP↔RLC directly wired: PDCP and RLC entities are connected directly via per-bearer gates. All submodules now reside directly at NIC level -- the former PdcpLayer and LteRlc compound modules no longer exist.

  • Example simulations: simulations/nr/standalone_drb/ with multi-UE, multi-QFI configurations.

Ip2Nic decomposed, further module architecture improvements

The Ip2Nic module, which had accumulated various unrelated responsibilities over time, was decomposed. Several code fragments were factored out into separate modules:

  • analyzePacket() moved to Ip2Nic from PDCP: Packet classification (filling FlowControlInfo tags) was moved to where it logically belongs -- at the IP-to-NIC boundary. The IpFlowInd tag was eliminated. RLC type NED parameters (conversationalRlc, etc.) also moved from PDCP to Ip2Nic.

  • HandoverPacketHolderUe/Enb: Handover packet buffering was factored out of Ip2Nic into separate modules. X2 tunneled packets are now received via gates instead of C++ method calls.

  • TechnologyDecision: Dual Connectivity technology selection logic was extracted into a separate, configurable module that uses NED expressions.

Further module architecture improvements:

  • MAC turned into compound module: MAC is now a compound module with AMC and DL/UL Scheduler as proper cSimpleModule submodules (previously created via new in C++). They perform their own staged initialization.

  • UPF and PgwStandard now derive from INET's ApplicationLayerNodeBase.

  • PacketFlowObserver refactored to use OMNeT++ signals: Direct C++ calls from PDCP, RLC, and MAC into PacketFlowObserver were replaced with OMNeT++ signals, fully decoupling the observer from protocol modules.

  • Replaced method-call-based packet passing with gate connections in several places: LteHandoverManager, DualConnectivityManager, Ip2Nic (X2 path).

Type safety improvements

  • Strong typedefs: SIMU5G_STRONG_TYPEDEF macro applied to MacNodeId, DrbId, LogicalCid, and Qfi, preventing accidental mixing of ID types.

  • Direction enum: LteControlInfo.direction changed from unsigned short to a proper Direction enum.

  • C++ types extracted: Types previously defined in LteCommon.msg were moved into a dedicated LteTypes.h header.

  • ROHC header: PDCP header compression now uses a proper ROHC header representation instead of simply truncating the IP header.

  • FlowControlInfo: lcid field renamed to drbId.

Naming and layout cleanup

  • Gate renames throughout the NIC for clarity and consistency: MAC_to_RLC/RLC_to_MAC -> upperLayerIn/upperLayerOut and macIn/macOut; MAC_to_PHY/PHY_to_MAC -> phyOut/phyIn; filterGate -> dnPppg. Several inout gates split into separate input

    • output gates.

  • Submodule renames: pdcpUpperMux -> pdcpMux, rlcLowerMux -> rlcMux, pppIf -> dpPpp (in UPF/PGW).

  • Module renames: DualConnectivityManager -> DcX2Forwarder, LteHandoverManager -> HandoverX2Forwarder.

  • Improved NED layout of NIC internals for better visualization in Qtenv: data-path modules arranged vertically, control-plane modules on the left edge, dynamically created PDCP/RLC entities positioned between muxes.

Bug fixes

  • LteSchedulerEnb: Fixed multi-UE starvation in multi-DRB scheduling.

Other

  • Added tilx fingerprints (resistant to module renames) to the fingerprint test suite. Fingerprint test coverage for MEC simulations improved.

  • SplitBearersTable turned into std::ordered_map.

v1.4.5 (2026-07-09)

This release is a collection of bug fixes to the physical-layer error model (CQI and BLER computation), the MAC layer, and the uplink scheduler. Several of these fixes change simulation results for the affected configurations.

Tested with INET-4.5.4 and OMNeT++ 6.3, compatible with INET-4.6.0 and OMNeT++ 6.1 through 6.4.

PHY error model fixes

  • BLER table indexing: GetBLER_TU()/GetBLER_AWGN() indexed the CQI/BLER tables one row too low, making throughput results slightly optimistic.

  • CQI boundary condition: An SNR exactly at the minimum (minSnr, -14 dB) wrongly yielded the maximum CQI 15 instead of CQI 0, scheduling a noise-floor UE at the highest MCS.

  • CQI 0 handling: LteRealisticChannelModel::error() no longer treats CQI 0 (a valid "channel unusable" value, e.g. just after handover) as a fatal error; the packet is simply dropped.

MAC and scheduler fixes

  • HARQ process count: The harqProcesses NED parameter (whose NR default is 5) was ignored by the C++ code, which used a hardcoded value of 8. The code now honors the parameter, so NR uses 5 HARQ processes as v1.4.4 already intended. Contributed by Esteban Egea Lopez (Universidad Politécnica de Cartagena).

  • RAC grant sizing: A UE completing RACH on a poor uplink channel could get a grant too small to even carry a Buffer Status Report, leaving it unable to report its buffer and re-RACHing forever. Grants are now sized to at least 56 B.

Other fixes

  • PacketFlowObserverEnb: An unknown grant ID on an uplink MAC PDU (normal during handover) now logs a warning instead of throwing a fatal error.

  • PacketFlowObserver: BSR-only MAC PDUs (no RLC SDUs) are now tolerated instead of triggering a fatal error.

  • AmcPilotAuto: Using it with a D2D direction now fails with a clear error message; scenarios with D2D should set amcMode="D2D".

v1.4.4 (2026-05-24)

This release contains bug fixes and improvements, including more realistic MAC layer modeling and several MEC fixes.

Tested with INET-4.5.4 and OMNeT++ 6.3, compatible with INET-4.6.0 and OMNeT++ 6.1 through 6.4.

MAC improvements

  • RACH preamble collision modeling: UEs now pick a random preamble index when sending Random Access Channel (RAC) requests. The eNB detects collisions when multiple UEs choose the same preamble in a TTI, causing all colliding requests to fail. Failed UEs exercise the existing backoff/retry path. A new NED parameter numPreambles (default 64) controls the preamble pool size. While this is an abstraction of the real multi-step RACH procedure, it faithfully captures preamble contention (the primary source of access failures) with minimal additional model complexity.

  • NR MAC timer defaults adjusted: raResponseWindow changed from 3 to 20, retxBsrTimer from 40 to 320. The original values were the LTE defaults, too aggressive for NR's finer timing granularity. Also adjusted maxRacAttempts (10) and racBackoffMax (20) for both LTE and NR.

  • Default HARQ processes for NR changed to 5 (from 8), reflecting the asynchronous nature of NR HARQ.

  • RAC/BSR timer parameters are now configurable from NED (previously hardcoded).

Bug fixes

  • Ip2Nic: Fixed issue #302 -- packets arriving at the old gNB just after a handover are now forwarded to the new gNB over X2, instead of causing an error.

  • Ip2Nic: Fixed fallback to NR node ID when a UE has no LTE ID, which is necessary for handling NR-only UEs.

  • MAC: Fixed ASSERT failure on D2D mode switching (SinglePair-modeSwitching scenario). When switching from DM to IM mode, the MAC connection structure is now preserved with empty buffers instead of being destroyed, so that switching back to DM mode works correctly.

  • GtpUserX2: Fixed GtpUserMsg chunk length to 8B, consistent with GtpUser.

  • MecOrchestrator: Fixed contextIdCounter never being incremented, causing every MEC app to overwrite the previous map entry at key 0.

  • MecOrchestrator: Fixed missing return after a failure path that caused an end-iterator dereference.

  • MecAppBase: Fixed undisposed HttpMessageStatus objects on destruction.

  • MecResponseApp, MecRTVideoStreamingReceiver: Fixed missing localUePort parameter that was inadvertently removed during earlier refactoring.

  • RniService: Fixed incomplete CamelCase renaming that caused the service to not be found in the registry.

  • MEC: Fixed uninitialized variables that caused non-deterministic fingerprint failures in debug builds.

Other changes

  • Binder: getNextHop() renamed to getServingNodeOrSelf() for clarity.

  • UDP error handling: Refactored several application modules (including UeWarningAlertApp, UeRnisTestApp, UeRequestApp, and others) to use UdpSocket::ICallback, fixing errors when receiving ICMP "destination unreachable" indications. MEC apps now also properly close their UDP sockets.

  • Copyright headers adjusted: Replaced generic "Authors" lines with precise copyright lines and added SimuLTE copyright attribution to files derived from SimuLTE.

  • INET 4.6 compatibility: Added checksumMode parameter to emulation examples alongside the existing crcMode for backward compatibility.

  • TrafficLightController: Made backward compatible with OMNeT++ 6.1.

v1.4.3 (2026-02-18)

This release represents a major milestone in the complete overhaul of the Simu5G codebase to make it architecturally more compliant with the 3GPP specifications, modernize the code, and adopt the best practices of the INET Framework on which it is based. The goal is to pave the way for a clean implementation of new protocol features such as TSN support.

Tested with INET-4.5.4 and OMNeT++ 6.3, updated for INET-4.6.0 compatibility.

Key achievements in this release:

  • More explicit Control Plane modeling: Simu5G is advertised as a User Plane simulator, but since it was also used to model dynamic scenarios such as handovers, it always contained elements of the Control Plane distributed across various modules. The new direction is to make these elements more explicit and centralized, such as creating dedicated RRC (Radio Resource Control) and Session Management Function (SMF) implementations. It is an explicit non-goal to simulate Control Plane messaging -- its functionality will be implemented with C++ method calls across modules. Thus, Simu5G remains a User Plane simulator, but with the possibility to more faithfully model dynamic scenarios with heavy Control Plane involvement. While this goal is not fully realized in this release, many changes point into that direction.

  • Control info refactoring: Cleaned up UserControlInfo and FlowControlInfo by removing 5+ unused fields and splitting out smaller, focused tags. For example, IPv4 addresses, only used between Ip2Nic and PDCP, have been factored out into an IpFlowInd tag. This improves modularity, reduces coupling between protocol layers, and makes the code easier to maintain and extend.

  • Added vital missing fields to PDCP and MAC headers: Protocol layers now use proper header fields instead of "tunnelling" information via UserControlInfo and FlowControlInfo packet tags that would not exist in a real implementation. For example, PDCP sequence numbers are now carried in PDCP headers, and LCIDs are stored in MAC PDU subheaders. This makes the simulation more realistic and packet contents more inspectable in Qtenv.

  • Explicit setup of logical connections instead of on-the-fly discovery: This is a key architectural change, which also largely motivated the previous items. In previous iterations of Simu5G, data structures associated with logical connections / bearers were created in each protocol layer as they encountered packets that belonged to new connections. Moreover, part of the connection state was carried along by the packets in FlowControlInfo tags instead of stored inside the protocol. While this modeling approach still allowed for faithful simulation of the traffic while keeping the implementation simple, it has become a roadblock for implementing complex dynamic scenarios where connections come and go. In this iteration, centralized session and bearer management (SMF-like functionality) was added to the Binder module, and RRC modules were added to NICs to carry out local configuration. This brings the architecture closer to the 3GPP control/user plane separation, making it easier to implement features like handovers correctly. This is work in progress: SMF is still part of Binder and not a separate module, and connection setup is still triggered by the first packet of the connection hitting PDCP on the way out. However, moving the SMF code into its own module will be trivial, and the single Binder method call in PDCP can now be easily replaced with static configuration or with calls from a more detailed Control Plane implementation.

  • Removed incomplete MIMO support: Removed MIMO-related code and parameters. The existing MIMO code was incomplete (e.g., PMI values were computed but never used). Removing it simplifies the codebase and model parameterization, and avoids confusion about capabilities. MIMO support will be added in a future release, with a different approach.

  • Initialization cleanup: Reorganized module initialization into well-defined, Simu5G-specific init stages. This eliminates hidden cross-module dependencies, makes the initialization order explicit and verifiable, and prevents subtle bugs caused by modules accessing uninitialized data in other modules.

Further notable changes:

  • In UE models, masterId and nrMasterId were renamed to servingNodeId and nrServingNodeId. The old names were confusing because "Master" has a specific meaning in Dual Connectivity (Master eNB vs Secondary gNB), unrelated to the UE's serving node.

  • In UE models, the macCellId, nrMacCellId parameters were removed. In practice, the code already used the serving node ID as cell ID.

  • macNodeId assignment was moved to NED, and now it is based on the new simu5g_seq() NED function that generates an integer sequence. This replaces the earlier approach where node IDs were assigned by Ip2Nic during initialization, and stored back into the module parameters for other modules to use.

  • LteRlcPduNewData and LteRlcSdu packet chunks were converted to packet tags, as they represent internal metadata rather than actual protocol data.

  • In the C++ code, merged the ENODEB and GNODEB node type enum values into a single NODEB value, with a separate isNr flag where needed. This change simplified a large number of "if" conditions throughout the codebase.

To port your existing Simu5G simulations to this version, apply the following changes to the ini files:

  • Change masterId to servingNodeId (and nrMasterId to nrServingNodeId), unless it refers to the Master/Secondary distinction in a Dual Connectivity setup.

  • Remove macCellId and nrMacCellId parameter assignments for UE modules.

  • Delete ini entries that set the following removed MIMO-related parameters: numRus, ruRange, ruStartingAngle, ruTxPower, antennaCws, muMimo, pmiWeight, lambdaMinTh, lambdaMaxTh, lambdaRatioTh, feedbackGeneratorType.

  • For initialTxMode, the following values are no longer valid: SINGLE_ANTENNA_PORT5, OL_SPATIAL_MULTIPLEXING, CL_SPATIAL_MULTIPLEXING, MULTI_USER. Remove the parameter assigment to use the default.

There are many more changes that potentially affect existing simulations, and projects extending, or built on top of, Simu5G. They cannot all be covered here in detail - see the git history for details.

v1.4.2 (2025-11-27)

This is primarily a bugfix release.

  • Pdcp: Fixed Dual Connectivity bug where separate PDCP entities were incorrectly created for LTE and NR legs of a Split Bearer instead of using a single shared entity. This fix breaks RLC-UM packet loss statistics which (incorrectly) inferred packet loss from PDCP sequence numbers.

  • RlcUm: Removed packet loss statistics that incorrectly relied on PDCP sequence numbers (PDCP sequences are not contiguous in Dual Connectivity setups)

  • PacketFlowManager: Renamed to PacketFlowObserver, updated NED documentation.

  • Statistics collection refined, e.g. remove recording "sum" and/or "mean" where it does not make sense; use new "rateavg" filter for computing average throughput.

  • Binder: New utility functions: isGNodeB(), getUeNodeId().

  • Apps: Added sequence numbers to VoIP and VoD packet names, to facilitate tracing with Qtenv.

  • NED documentation: Added content to simu5g-index.ned including version number and WHATSNEW.

v1.4.1-sdap-2 (2026-03-03)

This release improves on the simu5g-1.4.1-sdap release that added SDAP (Service Data Adaptation Protocol) layer support to Simu5G. Contributed by Andras Varga (OMNeT++ Core Team).

The most important changes:

  • New simulations that exercise the code more: Multi-UE, multi-app, multi-QFI configurations were added into omnetpp_drb.ini under nr/standalone. Based on the Simu5G#294 bug report by Jonathan "Toaaster" Ebert.

  • Fixed QFI propagation: QFI was originally added to packets by the application (VoipSender) as a packet tag (QfiTag). However, this tag did not make it to UPF, because it was already stripped by the local PPP interface on transmission. This mechanism was replaced by the VoipSender app setting DSCP on the packet, which UPF now interprets as QFI (simplified PDR matching). From then on, QFI is now carried through the GTP-U tunnel in the GTP header (mirroring the real 5G PDU Session Container extension header), instead of relying on QoS tags that were being stripped by PPP. The gNB extracts QFI from the GTP-U header to restore QoS tags for SDAP routing.

  • DRB configuration changes: The DRB configuration is now split between SDAP and MAC layers, each only knowing as much as they need for their operation. QFI-to-DRB routing configuration went into sdap.drbConfig, while QoS parameters for the scheduler (GBR, delay budget, PER, priority) went into mac.drbQosConfig. Moreover, DRB configuration is now specified in JSON, replacing the previous text file-based configuration.

  • Fixed multi-UE DL starvation (fixes Simu5G#294): MacDrbMultiplexer incorrectly used LCID as the nrRlc[] array index, assuming LCID equals the DRB index. When multiple UEs shared the same DRB, only the first UE received data. Fixed by learning the LCID-to-gate mapping from RLC-to-MAC traffic.

  • MEC fixes: There were several bug fixes in the MEC code, such as MecOrchestrator (contextId counter was never incremented), MecOrchestrator (missing return after failure path causing end-iterator dereference), MecAppBase (eliminate undisposed objects), fix uninitialized variables in various modules (fixing long-standing fingerprint failures of certain MEC simulations in debug mode).

v1.4.1-sdap (2025-10-06)

Compatible with OMNeT++ 6.2.0 and INET 4.5.4.

This specialized branch release introduces SDAP protocol support, multiple DRBs and advanced QoS capabilities to Simu5G for enhanced 5G network simulations. Please note that future main releases may not include these features or may incorporate them in a different form, as the primary development focus remains on architectural refactoring and foundational improvements. The changes were contributed by Mohamed Seliem (University College Cork), with improvements by Andras Varga (OMNeT++ Core Team).

Reference paper: "QoS-Aware Proportional Fairness Scheduling for Multi-Flow 5G UEs: A Smart Factory Perspective". Mohamed Seliem, Utz Roedig, Cormac Sreenan, Dirk Pesch. IEEE MSWiM, 2025.

New Features:

  • Added an SDAP protocol implementation with reflexive QoS capabilities (NrSdap and ReflectiveQosTable modules). Available using the NRUeSdap (UE) and gNodeBSdap (gNodeB) node types that contain the NRNicUeSdap and NRNicEnbSdap NIC types, respectively.

  • DRB (Data Radio Bearer) support with multi-QFI/QoS handling for realistic 5G bearer management simulations. This feature is available using NRUeDrb (UE) and gNodeBDrb (gNodeB) node types that contain the NRNicUeDrb and NRNicEnbDrb NIC types, respectively. It can be configured using the numDrbs parameter. QFI-to-DRB mappings can be defined in a context file (see SDAP's qfiContextFile parameter) with 5QI parameters and QoS requirements.

  • QoSAwareScheduler with QFI-based Proportional Fair scheduling using QfiContextManager. Enable QoS scheduling with LteMacEnb.schedulingDisciplineDl/Ul="QOS_PF".

  • Better representation of compressed headers in PDCP. (Note that header compression is disabled by default; enable using PDCP's headerCompressedSize parameter.)

  • New example simulations: simulations/nr/standalone/omnetpp_sdap.ini and omnetpp_drb.ini, each with Standalone, VoIP-DL, and VoIP-UL configurations demonstrating SDAP functionality and multi-DRB support with QoS-aware scheduling.

v1.4.1 (2025-10-06)

This is a minor update that brings further refactoring of the C++ code for clarity, improvements in the C++ interface of the Binder module, and some minor bug fixes. These improvements were contributed by Andras Varga (OMNeT++ Core Team).

Notable changes:

  • Binder: Partial rationalization of the C++ interface, via renaming/replacing/removing methods. See the git history for changes.

  • Updated IP addresses in the IPv4 configuration files: use 10.x.x.x addresses for the Core Network, and 192.168.x.x addresses for external addresses

  • Visual improvement: node IDs are now displayed over module icons

  • In MEC, do not use module IDs for bgAppId, deviceAppId and other IDs, and do not encode module ID into module names. That practice made simulations brittle for regression testing via fingerprints.

  • PDCP: Eliminated tweaking of srcId/destId in FlowControlInfo when sending downlink packets over the X2 link in a Dual-Connectivity setup.

  • Various additional fixes and changes to improve code quality.

v1.4.0 (2025-09-18)

Compatible with OMNeT++ 6.2.0 and INET 4.5.4.

This release marks an important milestone in the ongoing transformation of Simu5G. While not introducing behavioral changes, this intermediate release focuses on restructuring the codebase to improve clarity, safety, and maintainability. Major updates include a reorganized directory structure, enforcing a consistent naming convention, making make packets more easily inspectable, and refactoring of parts of the C++ code to pave the way for changes in future versions. Although the release is not source-compatible with previous versions, existing simulations will continue to work unchanged once adjusted to follow the various rename operations. These improvements were contributed by Andras Varga (OMNeT++ Core Team).

Renames:

  • Sources are now under src/simu5g/ instead of just src/, so that C++ includes start with "simu5g/". This helps identifying Simu5G includes when Simu5G is used as a dependency of other projects.

  • Some folders were moved inside the source tree to a more logical location. For example, the simu5g/nodes/mec/ subtree was promoted to simu5g/mec/.

  • Several source folders were renamed to more closely follow the all-lowercase convention. For example, mec/UALCMP/ became mec/ualcmp/, and mec/MECPlatform became just mec/platform.

  • Several classes were renamed to ensure that only the first letters of acronyms are uppercase. For example, MECHost became MecHost.

  • Several parameters were renamed to enforce camelcase names. For example, bs_noise_figure became bsNoiseFigure, and fading_paths became numFadingPaths. If you have existing Simu5G simulations, review the ini files carefully and update the parameter assignments accordingly. (Caveat: Assignment lines that refer to the old names will be simply ignored by the simulation -- there is no error message for that!)

  • The PdcpRrc modules were renamed to just Pdcp. Likewise, pdcpRrc submodules in NIC compound modules became pdcp.

Further refactoring:

  • Several protocol header classes, while defined in msg files, contained heavy customization in C++ code, including the addition of new fields. Since the writing of those classes, the message compiler in OMNeT++ gained enough features so that most of the customizations were no longer needed, and the desired effect could be achieved in msg files only. This refactoring has the benefit of making packets more inspectable from Qtenv, and packet contents can now be serialized using parsimPack (useful for more thorough fingerprint tests).

  • MacCid is a central data type that pairs an LCID with a nodeId to uniquely identify a logical channel. It used to be a packed integer, and now it was turned into a C++ class with separate fields for the node ID and LCID and with accessor methods, for increased type safety.

  • carrierFrequency used to be a variable of the type double throughout the codebase. The type was changed to GHz (using INET's units.h) for increased type safety. This also helped identifying a bug in certain channel models (LteRealisticChannelModel, BackgroundCellChannelModel) where a double representing GHz instead of Hz was used in computing path loss, resulting in underestimated path loss values.

  • Binder received several WATCHes for increased transparency in Qtenv, and an overhaul of a subset of its API and internal data structures.

  • In the Pdcp modules, the unused EUTRAN_RRC_Sap port (and associated handling code) was removed.

  • Refactoring of internals in several protocol modules, including MAC, PDCP and RLC implementations.

Build:

  • Made the command line build consistent with the IDE build. src/Makefile is now generated/updated implicitly on every build, no need to type "make makefiles".

v1.3.1 (2025-09-18)

This is a minor update for Simu5G-1.3.0. In addition to fixing regressions in the previous release and making some cosmetic improvements, the main highlight of this release is the revamp of the fingerprint test suite, which now provides a more comprehensive safety net against future regressions. Changes in this release were contributed by Andras Varga (OMNeT++ Core Team).

Changes:

  • Example simulations: Marked abstract configs as such (abstract=true) in omnetpp.ini files
  • FlowControlInfo's MacNodeId fields are now properly shown in Qtenv object inspectors
  • Replaced EV_ERROR << lines with throwing cRuntimeError
  • TrafficLightController: fixed startState NED parameter (also changed type from int to string)
  • Fingerprints: CSV files merged into simulations.csv, added missing simulations, standardized on the set of fingerprints computed (tplx, ~tNl, sz), translated gen_runallexamples.py into Python and improved it

Fix regressions in v1.3.0:

  • MECResponseApp: fixed wrong @class annotation
  • BackgroundScheduler: fix "binder_ not initialized" error
  • MecRequestForegroundApp, MecRequestBackgroundGeneratorApp: add back lost parameter defaults
  • BackgroundCellTrafficManager: fix "Not implemented" thrown from getBackloggedUeBytesPerBlock()
  • tutorials/nr/omnetpp.ini: fix missing unit for txPower parameter (dBm)

v1.3.0 (2025-02-06)

  • Compatible with OMNeT++ 6.1.0 and INET 4.5.4
  • New modules: MultiUEMECApp, MecRnisTestApp, UeRnisTestApp
  • Added NED documentation for modules
  • Increased reusability of modules via changes such as replacing hardcoded module paths in the C++ code with NED parameters (binderModule, macModule, etc.), and elimination of ancestorPar() calls by introducing local parameters instead. *
  • Other NED adjustments, such as removal of unused NED parameters and splitting NED files to have one module per file. See doc/NED-changes.txt for details. *
  • Extensive C++ modernization, and adaption of more OMNeT++ best practices. *
  • Various bug fixes.
  • Changes marked with an asterisk were contributed by Andras Varga (OMNeT++ Core Team).

v1.2.3 (2025-01-10)

  • Added support for OMNeT++ 6.1.0 and INET 4.5.4.

v1.2.2 (2023-04-19)

  • Compatible with OMNeT++ 6.0.1 and INET 4.5.
  • Tested on Ubuntu 22.04 and macOS Ventura.

v1.2.1 (2022-07-19)

  • Compatible with OMNeT++ 6.0 and INET 4.4.0.
  • Tested on Ubuntu 20.04.
  • Modifications to support the latest versions of OMNeT++ 6.0 and INET v4.4.0.
  • Refactoring of simulation and emulation folders.
  • Various bug fixes.

v1.2.0 (2021-08-30)

  • Compatible with OMNeT++ 6.0 (pre10 and pre11) and INET 4.3.2.
  • Tested on Ubuntu 16.04, 18.04, 20.04, macOS Catalina, and Windows 7.
  • Added modelling of ETSI MEC entities.
  • Support for real-time emulation capabilities (Linux OS only).
  • Modelling of background cells and background UEs for larger scale simulations and emulations.
  • Several bug fixes.

v1.1.0 (2021-04-16)

  • Compatible with OMNeT++ 5.6.2 and INET 4.2.2.
  • Tested on Ubuntu 16.04, 18.04, 20.04, macOS Catalina, and Windows 7.