A report just published by the EBU concludes that 5G could meet the distribution requirements of both public service and commercial broadcasters. However, there are significant structural barriers that will need to be overcome to realise the potential of 5G.
There has been interest in the concept of broadcast to mobiles since the mid 2000s. The “Mobile Zone” introduced by IBC in 2005 was the forerunner of “Content Everywhere”. Those early days saw a plethora of mobile broadcast proposals including DVB-H, DMB, DAB-IP, ISDB-T and MediaFLO.
Each of these technologies struggled with the same issue. Each was premised on the building of a dedicated mobile broadcast network. But success would depend on widespread availability of compatible handsets. The very existence of multiple candidate technologies and a lack of globally harmonised spectrum meant smartphone manufacturers, whose business models are built around offering common products to multiple markets, found it impossible to predict which, if any, of the technologies would succeed. Without global scale, compatible handsets would be expensive and undermine any consumer proposition.
It was also never clear who could justify the investment in a mobile broadcast network. In the broadcast world, channels share the capital and operational costs of a common broadcast infrastructure. Viewers can use any TV set to watch their channel of choice. Building of a parallel duplicate network just to reach mobile users - who probably wouldn’t have compatible handsets - was not a compelling business case.
Was there an opportunity for mobile operators? The need for premium-priced compatible handsets would place an operator at a disadvantage in their core mobile communications business. Also, at the time, they had limited interest in video services and there was little evidence of appetite for the supplementary pay TV subscription that would be required to cover additional network capex and service opex.
Recognition of the weakness of the business case coincided with the launch of the iPhone and its app store which introduced the concept of today’s smartphone and radically shifted mobile phone usage. It was also about the time that 3GPP, the body that develops and maintains global mobile technology standards, was looking to improve on the lacklustre mobile broadband capabilities of 3G.
3GPP introduces new features and functionalities in successive “releases” of its standards. LTE, or “4G”, was introduced in Release-9 in 2010. One new capability was eMBMS - evolved Multimedia Broadcast Multicast Services or “LTE-Broadcast”. This enabled multiple users in the same cell to access the same live stream, rather than the network having to serve multiple unicast streams.
Further enhancements have been introduced in subsequent releases: MooD (MBMS Operation on Demand) dynamically switches from unicast to multicast as the number of users consuming the same stream in a cell reaches a defined threshold.
LTE-Broadcast has had limited take-up. The Global Mobile Suppliers Association (GSA) reported last summer that 41 mobile operators had either evaluated or trialled the technology. Only five commercial services have been launched, with none in Europe. Once again, the technology has been constrained by the fact that operators are reluctant to deploy unless compatible smartphones are readily available while handset manufacturers are reluctant to produce if compatible services aren’t being offered. Where it has launched, LTE-Broadcast has largely been confined to top-tier smartphones. It has also been held back by the reticence of Apple to implement it in any of its popular iPhones.
The first 5G standards were introduced in Release-15 in the spring of 2018 but “LTE-based 5G Terrestrial Broadcast”, built on top of the LTE core network will only appear in Release 16, due to be completed this month after a short COVID-induced delay. Release-17, currently scheduled for the second half of 2021, will see the introduction of 5G broadcast based on a more versatile 5G core.
The EBU’s report attempts to understand the implications and opportunities offered by this evolving but complex environment.
Tech Expert: 5G
Acknowledging that broadcasters offer an increasingly wide range of content and services across a variety of distribution platforms, the EBU investigated the applicability of 5G to the delivery of curated linear broadcast; on-demand non-linear services and “enhanced media services” that combine complimentary linear and non-linear services. The main focus was on delivery to mobiles, tablets and in-car infotainment devices but also examined the relevance of the new technology for delivery to suitably modified TV sets in the home.
The report’s remit was also very focused on evaluating how 5G supports requirements important to PSBs:
- Universal coverage and access
- Free-to-air access
- Defined quality of service independent of audience size
- Service integrity that ensures content cannot be modified by third parties,
- Compliance with national prominence regulations
- Accessibility to people with disabilities
The EBU concluded that technically 5G Broadcast could fulfil many broadcaster requirements for the distribution of linear services to portable devices. Unlike LTE, the new standards will accommodate the idea that media organisations could operate dedicated 5G Broadcast networks independently of mobile operators. A free-to-air transmission mode would allow linear services to be made available to all mobile devices, regardless of a user’s mobile network.
5G Broadcast network architecture is based around single frequency networks with inter-site distance of around 15km. Providing near-universal coverage for portable devices would require Low-Power Low-Tower transmitters to supplement conventional High-Power High-Tower and Medium-Power Medium-Tower broadcast transmitter sites. This would increase costs but could be facilitated by collaboration between mobile and broadcast infrastructure providers.
Dedicated spectrum will also need to be secured. The report discusses L-Band (3GPP band 32: 1452 – 1496 MHz) that is potentially available in parts of Europe and the sub-700 MHz UHF band, currently widely used for DTT and PMSE. For the latter, coexistence between 5G Broadcast and DTT would need to be carefully managed. However, to be successful, harmonisation across markets beyond Europe will be required to establish the global scale required to engage smartphone manufacturers. Support from big markets such as China or India could tip the balance.
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5G for nonlinear services
The report notes that 5G Mobile Broadband is, in principle, well suited to unicast delivery of nonlinear services. It provides improved latency and reliability compared with 4G LTE which is already supporting many broadcaster on-demand and catch-up apps.
However, with initial European 5G deployments being based mainly on the 3.5GHz band, cell sizes are small and coverage is currently concentrated in urban areas. Achieving anything close to universal coverage will take a long time.
As access to 5G mobile broadband is dependent on a mobile subscription, free-to-air access is a challenge – as it is over domestic internet connections and WiFi. The ability of 5G Broadcast and 5G Mobile Broadband to support linear and non-linear services is summarised in the table.
While 5G can offer many features that are useful and attractive to broadcasters, as the technology matures actual implementation in handsets and network systems will depend on each stakeholder’s perception of market demand.
However, the mobile industry trend towards network virtualisation may change the dynamic in infrastructure supply. Mavenir, one of a new generation of network software providers, has already demonstrated a virtualised neutral host cell site solution designed to increase multi-operator capacity in high footfall areas such as shopping centres, transport hubs and stadia. It doesn’t take a massive leap of the imagination to see how such a system could potentially support standalone 5G Broadcast alongside conventional mobile operators.
If 5G is to progress further than earlier mobile broadcast technologies, new business models will be needed to achieve scale, engage all the necessary stakeholders and facilitate collaboration. EBU’s report identifies the 5G features relevant to the media industry and is intended to shape the organisation’s ongoing work on the technology.
The full report can be downloaded at EBU Tech Report 054.
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