For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

For the purposes of the present document, the following symbols apply:

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905. CAS CFI DRX eMBMS FeMBMS HPHT ISD LPLT MBMS MBSFN MCCH MPMT MTCH NAS PBCH PCFICH PDCCH PDSCH PMCH PSS ROM RRC RRM SSS TV

The main aspects of the LTE-based 5G terrestrial broadcast described in this specification are:

• radio network comprising only MBMS-dedicated cells or FeMBMS/Unicast-mixed cells TS 36.300 as transmitters; and
• ROM devices and UEs supporting FeMBMS TS 23.246 as receivers.

MBMS-dedicated cells support only MBMS transmission and do not support uplink transmission. MBSFN subframes of a MBMS-dedicated cell do not have a control region and can therefore be 100% allocated to MBMS. Non-MBSFN subframes, also called Cell Acquisition Subframes (CAS), which contain the control region, are used for transmission of the system acquisition signals (PSS/SSS), PDCCH, and system information on PBCH and PDSCH. CAS are transmitted with a periodicity of 40ms and use subframes with Δf = 15 kHz. PBCH of a MBMS-dedicated cell uses a different scrambling sequence initialization than PBCH of a non-MBMS-dedicated cell, which prevents UEs that do not support MBMS-dedicated cell from camping on it. For more information about MBMS-dedicated cell see TS 36.300. Multicast data is transmitted over PMCH. PMCH supports SFN transmission, where multiple eNBs synchronously transmit the same waveform. Multiple numerologies are supported for PMCH (see clause 6.1), tailored for different scenarios (e.g. support of different mobility and ISD). A single cell can belong to multiple (up to 8) SFN areas, where different SFN areas may have different numerologies. The PMCH carries the MCCH and MTCH logical channels. The MCCH provides scheduling information for multicast data over the MTCH. The MTCH contains user plane data. MCCH scheduling information is provided in system information. ROM devices support MBMS reception but do not support uplink transmission. ROM devices may not have USIM. As such, ROM devices do not support two-way signalling procedures with the network, including connection establishment procedures and security procedures. ROM devices only support the idle mode. Not all idle mode procedures are supported, as described in clause 7.3. For more details on ROM devices see clause 7, clause 15.11 of TS 36.300, TS 23.246 Annex D and clause 4 of TS 24.116.

In Release 14, the use cases and scenarios for eMBMS services based on LTE have been expanded to include terrestrial broadcasting (the feature also referred to as "EnTV"). This included new requirements:

• network dedicated to TV broadcast via eMBMS;
• SFN deployments with ISD significantly larger than a typical ISD associated with typical cellular deployments;
• support for ROM device.

In Release 16, a gap analysis documented in TR 36.776 compared the Release 14 LTE terrestrial broadcasting capabilities with the requirements for 5G dedicated broadcast networks in TR 38.913. As a result of this analysis, the following two requirements were deemed unfulfilled by Release 14 LTE eMBMS:

1. Support for service over large geographic area, including SFN with ISD > 100km;
2. Support for mobility scenarios including speeds of up to 250 km/h.

In relation to the first requirement, the new ISD of 125 km, referred to as HPHT network, with omni-directional transmitters was defined. The following two ISD were also included in the evaluation:

• 15 km, referred to as LPLT network with sectorized cells;
• 50 km, referred to as MPMT network with omni-directional transmitters.

The first requirement is associated with receivers with high-gain rooftop directional antennas, low mobility and a predominantly line-of-sight channel. The second requirement is associated with receivers in cars, with external omni-directional antennas. In addition to the above two requirements, a third requirement was added related to improving the CAS reception for both large ISD and high mobility scenarios.

In Release 14, the following key RAN enhancements were made to the specifications to enable LTE terrestrial broadcast:

• MBMS-dedicated cell TS 36.300;
• MBSFN subframes using Δf = 1.25 kHz TS 36.211, with a cyclic prefix duration of 200µs and a symbol duration of 1ms;
• New information blocks on PBCH and PDSCH of CAS TS 36.300, TS 36.331:
  • MIB-MBMS is transmitted with a 40ms periodicity and updated every 160 ms; and
  • SIB1-MBMS is transmitted with an 80ms periodicity and updated every 160 ms, containing information relevant for receiving MBMS service and, optionally, the scheduling of other system information blocks;
• MBMSInterestIndication RRC signalling procedure (see clause 4.1).

In Release 16, the following RAN enhancements were made to address the use cases described in clause 4.2:

• MBSFN subframes using Δf = 0.37 kHz, with a cyclic prefix duration of 300µs and a symbol duration of 3ms, for the support of large ISD;
• MBSFN subframes using Δf = 2.5 kHz, with a cyclic prefix duration of 100µs and a symbol duration of 0.5ms, for the support of high mobility;
• The following enhancements on the CAS:
  • PDCCH enhancements:
    • CFI indication in MIB TS 36.331 to avoid the need to decode PCFICH; and
    • New aggregation level 16;
  • Repetition of PBCH to increase its robustness.

In Release 17, the following RAN enhancement was introduced to enable deployment of LTE-based 5G terrestrial broadcast in broadcast UHF spectrum, where the channelization is 6/7/8MHz (depending on the geography):

• PMCH bandwidth of 30, 35 and 40 PRBs (corresponding to 6/7/8MHz), applicable for CAS bandwidth of 15 or 25 PRBs (corresponding to 3 and 5MHz).