Category: 3GPP Implementations
What This Project Implements
This page sets out what is in scope for the 5G Broadcast Reference Tools: the transmitter (rt-mbms-tx) and receiver (rt-mbms-modem), the LTE-based 5G Broadcast radio mode (FeMBMS), and the per-release features they support. It also shows the high-level architectures in which they are used. Use it to check which capabilities are implemented before planning a test. For step-by-step setups, see Tutorials.
Technical documentation providing context to this project can be found in the link below.
High-level architecture
5G Broadcast with Multimedia delivery protocols
The diagram below shows the 5G Broadcast tools combined with the multimedia delivery protocols (FLUTE-based file delivery), from transmitter through to receiver.
Repositories used in this architecture:
5G Downlink Media Streaming (5GMSd) over eMBMS
This second diagram shows 5G Downlink Media Streaming (5GMSd) delivered over eMBMS (enhanced Multimedia Broadcast Multicast Service), combining the 5G Media Streaming tools with the broadcast chain.
Repositories used in this architecture:
- 5G Media Streaming: Resources
- 5G Broadcast: Resources
- Multimedia content delivery protocols: Resources
- 3GPP RAN and Core Platforms: Resources
- Common Tools: Repositories
Features under implementation
Implementation status (high level)
At the release/feature level, the reference tools rt-mbms-tx (transmitter) and rt-mbms-modem (receiver) implement the LTE-based 5G Broadcast features from 3GPP Release 14 through Release 19:
| 3GPP Release | Key features | rt-mbms-tx | rt-mbms-modem |
|---|---|---|---|
| Rel-14 (EnTV) | 1.25 / 7.5 kHz SCS; CAS; MBMS-dedicated cell; 256-QAM; MIB-MBMS; SIB1-MBMS | Implemented | Implemented |
| Rel-16 (LTE_terr_bcast) | 2.5 / 0.37 kHz SCS; new RS patterns; PDCCH Format 4; MBSFN-AreaInfo-r16; ROM | Implemented | Implemented |
| Rel-17 (bands part 1) | 6/7/8 MHz PMCH bandwidths (30/35/40 PRB); pmch-Bandwidth-r17; Band 107 | Implemented | Implemented |
| Rel-18 (bands part 2) | Band 108 (470 to 698 MHz, receive-only); RF specs | Implemented (band table) | Implemented (band table) |
| Rel-19 (PMCH Phase 2) | Time / frequency interleaving; cyclic shift; PMCH MCS tables; TBS scaling; extended SI periods; RRC v1900 chain | Implemented | Implemented |
| Rel-19 (CAS muting) | CAS muting for PSS / SSS / PBCH; SIB1-MBMS v1900; UE capability | Implemented | Implemented |
| Rel-19 (new bands) | Bands 112 (470 to 608 MHz) and 113 (606 to 698 MHz) | Implemented | Implemented |
This is a high-level, release-level view. Some items are receive-only or transmit-only by nature (for example UE capability signalling applies on the modem side), and some Release 18/19 band support is at the frequency-lookup and configuration level. For the full standards background, see Standards: LTE-based 5G Broadcast. The board below gives the finer, per-feature breakdown.
Support of features in rt-mbms-tx and rt-mbms-modem
Each release is audited feature by feature at both ends of the chain: rt-mbms-tx (transmit) and rt-mbms-modem (receive). Where support has not yet been confirmed, the feature is marked On hold and its note says so.
The features use these recurring 3GPP terms: MBSFN (Multicast-Broadcast Single-Frequency Network, where several cells transmit the same signal in sync); SCS (subcarrier spacing, the frequency gap between subcarriers, in kHz); PRB (Physical Resource Block, the basic unit of radio bandwidth allocation); MIB/SIB (Master/System Information Block, broadcast control information); PDCCH/PBCH/PMCH/PCFICH (Physical Downlink Control / Broadcast / Multicast / Control Format Indicator Channels); CFI (Control Format Indicator); RRC (Radio Resource Control signalling).
Rel-14Release 14 features (EnTV)6/8
| Feature | rt-mbms-tx | rt-mbms-modem | Notes |
|---|---|---|---|
| MBSFN subframes using SCS = 1.25 kHz | Yes | Yes | |
| MIB-MBMS | Yes | Yes | |
| SIB1-MBMS | Yes | Yes | |
| MBMSInterestIndication RRC signalling procedure | To check | To check | support not yet confirmed at either end |
Rel-16Release 16 features (LTE_terr_bcast)all implemented
| Feature | rt-mbms-tx | rt-mbms-modem | Notes |
|---|---|---|---|
| MBSFN subframes using SCS = 0.37 kHz | Yes | Yes | |
| MBSFN subframes using SCS = 2.5 kHz | Yes | Yes | |
| PDCCH enhancements: CFI indication in MIB to avoid the need to decode PCFICH | Yes | Yes | |
| PDCCH enhancements: New aggregation level 16 (PDCCH Format 4) | Yes | Yes | |
| Repetition of PBCH | Yes | Yes | |
| MBSFN-AreaInfo-r16 (subcarrierSpacing, timeSeparation) | Yes | Yes | |
| Receive-Only Mode (ROM) redirect | Yes | Yes |
Rel-17Release 17 features (bands part 1)all implemented
| Feature | rt-mbms-tx | rt-mbms-modem | Notes |
|---|---|---|---|
| PMCH bandwidth of 30, 35 and 40 PRBs (corresponding to 6/7/8 MHz) | Yes | Yes | |
| Band 107 (UHF) | Yes | Yes |
Rel-18Release 18 features (bands part 2)all implemented
| Feature | rt-mbms-tx | rt-mbms-modem | Notes |
|---|---|---|---|
| Band 108 (470 to 698 MHz, receive-only) | Yes | Yes | band-table level (frequency lookup and configuration) |
Rel-19Release 19 features (PMCH Phase 2, CAS muting, new bands)all implemented
| Feature | rt-mbms-tx | rt-mbms-modem | Notes |
|---|---|---|---|
| PMCH time interleaving (N subframes) | Yes | Yes | |
| PMCH frequency interleaving | Yes | Yes | |
| PMCH cyclic shift | Yes | Yes | |
| PMCH MCS tables 11.1-1 / 11.1-2 | Yes | Yes | |
| Extended SI scheduling periods | Yes | Yes | |
| CAS muting (PSS / SSS / PBCH) | Yes | Yes | |
| Bands 112 and 113 (UHF, receive-only) | Yes | Yes | band-table level (frequency lookup and configuration) |
Support of features for rt-mbms-tx-for-qrd-and-crd
Note that the 5G Broadcast Transmitter for QRD (Qualcomm Reference Design) and CRD (Commercial Reference Design) is an extension of an MBMS-enabled eNodeB tailored to operate as a 5G Broadcast transmitter. Only MBMS/Unicast-mixed cell is supported alongside pre-Rel-14 features.
Getting Started
A practical route into the tools:
- Start with SDR - HLS Playback over 5G Broadcast in the Tutorials index, the simplest receiver-only setup; the other tutorials there build on the same components (transmitter, Docker, Android seamless switching).
- Check the Resources page for tagged versions of rt-mbms-tx and rt-mbms-modem.
Roadmap
This page tracks the planned and in-progress work for the 5G Broadcast Reference Tools. The general roadmap gives the overall direction; the developer boards below break the work down by component. Each links to a GitHub Kanban board, where the current status is authoritative.
General Project Roadmap
The Kanban board below tracks the planned and in-progress work for the 5G Broadcast Reference Tools (hybrid TV/Radio delivery, transmitter and receiver components). It is maintained live on GitHub.
Developer Kanban Boards
Seamless switching between broadcast and unicast
Seamless switching between LTE-based 5G Broadcast and OTT unicast
MBMS Modem - Rel 17 Support
The required issues and features requests to make the MBMS Modem Rel 17 compliant
5G Broadcast Transmitters
Project for any improvements to the rt-mbms-tx and rt-mbms-tx-for-qrd-and-crd.
Web User Interface
Project for any improvements to the rt-mbms-wui
Related
- Resources
- Tutorials
- Related project: 5G Broadcast - Emergency Alerts
- Standards: 5G Broadcast — the full specification list, including ETSI TS 103 720, the FeMBMS waveform implemented by rt-mbms-tx and rt-mbms-modem
- Standards: Multimedia Delivery Protocols — the FLUTE/ROUTE transports that carry content over the broadcast bearer
- Technical documentation: 5G Broadcast on the Tech portal
- Technical documentation: Non-Terrestrial Networks on the Tech portal — satellite delivery scenarios, including MBS Broadcast over NTN
- Standards: Non-Terrestrial Networks — ETSI TS 103 720 in GEO satellite broadcast scenarios