BEITC 24 Report: Worldwide 5G TV Update

The appetite for broadcast content over mobile devices has reached several important milestones, providing more opportunities for the latest versions of ATSC and DVB content to be distributed as cellular data without a SIM card or a cellular subscription. The irony is that only a handful of experimental mobile devices can receive 5G TV yet, and much of it in the US will be broadcast to viewers on a portion of the UHF TV broadcast band the FCC auctioned off.

This report is based on the 2024 BEITC paper “How IP-Based Broadcast Meets 5G For Resilient and Sustainable Media Distribution,” presented by Emily Dubs with the DVB Project, Geneva, Switzerland, and its content was edited for space. All graphics and information in this BEITC coverage are Courtesy of NAB.

There is no question that the world's broadcasting standards have been evolving towards IP-based approaches. At the same time, Third Generation Partnership Project (3GPP), the overarching standards developing organization (SDO) for mobile telecommunications, has begun to incorporate multicast and broadcast capabilities, one outcome of which is 5G Broadcast. The latter has the potential to play a role in the terrestrial delivery of digital television among the already well-established Digital Terrestrial Television Broadcasting (DTTB) systems.

The second DTTB generation includes ATSC 3.0; those from the DVB Project, notably DVB-T2, the iterations of ISDB-T in Japan; and the Digital Television Terrestrial Multimedia Broadcasting (DTMB) system developed in China.

ATSC 3.0

NextGen TV is known to the FCC and broadcasters as ATSC 3.0, the effective successor of ATSC 1.0 because ATSC 2.0 was never fully launched. ATSC 3.0 is broadcast in the US, South Korea, and Jamaica. It was released in 2019 and is specified in several distinct ATSC 3.0 documents, and it generally allows the independent evolution of the various aspects of the standard.

Unlike DVB-T2, ATSC 3.0 is not backwards compatible with its predecessor. However, it provides flexibility in the physical layer to cover a large range of service options thanks to a few additional tools that were not included in DVB-T2 for the sake of backward compatibility with DVB-T and the large installed base of antennas, as well as for cost efficiency of the required infrastructures and receivers.

The physical layer of ATSC 3.0, defined in A/322, was built upon the same basic architecture as DVB-T2, using COFDM modulation and low-density parity-check (LDPC) codes. ATSC 3.0 includes additional tools such as non-uniform constellations, advanced LDPC codes, and Multiple-Input Multiple-Output (MIMO).

This increased complexity results in a much higher payload capacity compared to the first-generation ATSC standard (ATSC 1.0/2.0) and its mobile/handheld extension (ATSC-M/H). It also achieves a small improvement in performance compared to DVB-T2, being very slightly closer to the theoretical Shannon limit, in addition to providing a wider operating range in terms of signal-to-noise ratio (SNR), as illustrated in Figure 1.

Figure 1. The Shannon limit is the maximum error-free data rate that can theoretically be transferred over a channel if the link is subject to random data transmission errors, for a particular noise level.

Figure 1. The Shannon limit is the maximum error-free data rate that can theoretically be transferred over a channel if the link is subject to random data transmission errors, for a particular noise level.

The transport layer, defined in A/331, is where the most significant difference between ATSC 3.0 and DVB-T2 lies. While the latter uses the widely adopted MPEG-2 transport stream (MPEG-2 TS) format, ATSC 3.0 introduces a fully IP-based core with a view to facilitating integration with the emerging trend towards the use of IP.

This fully IP-based approach makes it easier to combine over-the-air (OTA) broadcast signals with content received via broadband networks. In addition, together with its increased spectral efficiency and robustness compared to the first-generation standard, ATSC 3.0 marks a further step towards a system more suited to mobile broadcasting.

5G TV

Support of broadcast/multicast technology in 3rd Generation Partnership Project (3GPP) dates back to the early 2000s, as shown in Figure 2. The requirements for stand-alone broadcast – i.e. relying on a broadcast-only network, for downlink only traffic, and independent from cellular networks – were fully met in 3GPP Release 16 and include the UHF band 108 (470 to 698 MHz) since Release 18.

This mode enables broadcast deployments using existing UHF spectrum and television broadcast infrastructure such as Medium-Power Medium-Tower (MPMT) and High-Power High-Tower (HPHT) networks. Much of that UHF band in the US was auctioned in the 2016 US FCC Repack.

Figure 2. 5G Broadcasting has been endorsed as a stand-alone terrestrial broadcast system specification via ETSI TS 103 720 and most recently by ITU-R, where it is defined as a worldwide standard within the UHF band.

Figure 2. 5G Broadcasting has been endorsed as a stand-alone terrestrial broadcast system specification via ETSI TS 103 720 and most recently by ITU-R, where it is defined as a worldwide standard within the UHF band.

Cellular 5G Broadcast primarily focuses on mobility use cases but for free-to-air broadcast, in 5G standalone broadcast mode, it does not require the network to support unicast nor the device to have a SIM card or a cellular subscription. 

While unicast is not required, 5G Broadcast can alternatively be combined with unicast to deliver a hybrid user experience leveraging the best of unicast and broadcast technologies.

5GMS

To leverage new 5G features and capabilities for media distribution, 3GPP Release 16 defines a 5G Media Streaming (5GMS) System that enables media distribution over 5G networks by third parties other than Mobile Network Operators (MNOs). The 5GMS system allows 5G networks to provide technical and commercial opportunities for collaboration, beyond merely acting as a bit pipe.

The 5GMS System supports value-added services such as content hosting, network assistance and dynamic network Quality of Service (QoS) policies, as well as reporting of consumption and Quality of Experience (QoE) metrics for analysis and optimization purposes.

Such collaboration models facilitate video traffic monetization and revenue sharing between MNOs and content providers. While the first version of the 5GMS System focuses on media delivery over unicast, Multicast/Broadcast delivered using 5G NR [Ed: 5G New Radio or 5G NR is the part of the 5G specification also referred to as 5G Broadcast] is a key new feature introduced by 3GPP in Release 17, and the combination of this with 5GMS is specified in Release 18.

ATSC’s Global Harmonization Efforts

ATSC initiated several efforts towards global convergence of the main DTTB systems to “develop a common voice on international issues affecting the broadcast community” such as the threat of losing further spectrum. To date, second-generation DTTB systems are the most efficient physical layers for one-to-many delivery and are acknowledged as the most sustainable means of delivering large amounts of content to many users.

In addition, they rely on highly resilient HPHT infrastructure. Therefore, it would seem to make sense for these valuable DTTB systems to speak with a single voice on the world stage, as part of a global initiative to modernize their technologies in a way that would facilitate interworking with other networks, such as those specified by 3GPP.

While a convergence at the physical layer has proved difficult – the major obstacle being the lack of uniformity in the use of the broadcast spectrum throughout the world owing to the historical adoption of either NTSC, PAL, or SECAM systems, leading to the use of either 6 MHz or 8 MHz channels and resulting in varying payload capacities – efforts for subsystem-level convergence may be more practicable.

Indeed, technical commonalities, for instance with common video schemes or common multicast protocol profiles, would allow effective interaction at the application or transport layers and facilitate interworking. This can be achieved, for instance, through cross-organization collaboration during the respective work towards next-generation technologies. With this goal in mind, while adding Versatile Video Coding (H266/VVC) to its suite of standards, ATSC liaised with DVB and other organizations, including SBTVD and 3GPP, to seek potential alignment of ATSC VVC profiles like other standards.

The ATSC BCN

In line with moving towards a harmonized broadcast system that would be interoperable with 3GPP, a further area where ATSC is particularly active is the development of a Broadcast Core Network (BCN).

According to ATSC’s report on global convergence, the BCN project aims at designing core networking capabilities within the ATSC 3.0 broadcast system architecture to facilitate efficient interworking between broadcast towers beyond Designated Market Areas (DMAs) and potentially across heterogeneous networks. Indeed, the BCN is being designed to be agnostic to the DTTB system and to enable converged operation with other data-delivery networks, including 3GPP ones (LTE-based and NR-based 5G networks) and satellite.

Such a system will enable new business opportunities that require sourcing content from multiple data networks to achieve efficient data-delivery options. The ultimate goal is to broaden the utility of the ATSC 3.0 broadcast facilities to new use cases beyond linear television program delivery, such as Internet of Things (IoT) datacasting, enhanced interactivity, data or content offload, vehicular data download including enhanced GPS signaling, or software updates to game consoles.

ATSC’s project to specify a Broadcast Core Network that is agnostic to the DTT system will eventually allow converged operation within the available delivery networks. Furthermore, DVB’s recent work on adapting DVB-I to support 5G technologies will ensure that LTE-based and NR-based 5G networks can carry services with an appropriate – standardized and ‘TV-friendly’ – service layer that is likely to facilitate commercial success. Thanks to DVB-I, promising scenarios involve the seamless use of 5G Broadcast when available, or even DVB-NIP through hotspots when indoors, leveraging the existing infrastructure and well-proven DVB networks.

Emily Dubs’ BEITC paper went on to explain “Coexistance at the RF level – Time Division Multiplexing,” and provided details of several examples of service level collaboration contrasting ATSC 3.0 to DVB and ATSC 3.0 over 5G to DVB-I over 5G. These sections were highly technical and beyond the scope of this coverage but are available in the full paper from NAB.

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