One point to emerge clearly from the recent annual IBC 2019 broadcasting convention in Amsterdam was that the stampede towards IP from traditional media is gathering speed. At first sight this might suggest that digital terrestrial transmission is also dying, but this is only superficially true because the underlying technologies enabling multicast and broadcast will live on as overlays on top of the cellular infrastructure.
We have to distinguish carefully between the platform and the protocol here, remembering that the broadcasting industry has been set on migration over the latter some years but until recently many operators have been determined to hold on to their traditional distribution platforms. Even now bodies representing broadcasters, notably the EBU (European Broadcasting Union), remain set on defending terrestrial spectrum against mobile intrusion, despite that having been occurring now for over a decade.
The EBU still contends that digital terrestrial TV (DTT) – which because of its technical profile requires spectrum in the UHF band contested by mobile operators – remains the most effective means of ensuring that every citizen has access to free-to-air TV. The EBU advances several supporting arguments that look increasingly like red herrings, such as that mobile operators already have a large amount of spectrum not fully utilized in 2G and 3G networks that they could repurpose instead; that increased demand for mobile can also be met via several other frequency ranges (L‑band, 2.3 GHz, 2.6 GHz) not relevant for DTT; and that WiFi caters for the vast majority of wireless data traffic delivered to smartphones and tablets, offering higher capacity and cheaper data reception. The latter point may be partly true but WiFi is rarely ubiquitous and therefore to obtain a consistent experience on the move, cellular data is needed as well.
The EBU, in particular, has always stood up for its pubcaster members but now these are starting to desert the cause themselves. Some have realized for a while that the game is up for traditional broadcast distribution, although we must be clear what we are talking about here. This is not the end of linear TV, which is alive and well in the context of sports, live shows, news and even with potential for growth around esports. What is happening though is a shift from the broadcast domain to IP-based distribution for linear channels as well as on demand content and TV Everywhere, with mobile TV growth set to accelerate in the 5G arena.
This is evident now in the flow of money for infrastructure investment, which is focused on the twin pillars of fiber and 5G to the detriment of satellite and DTT. Cable though will converge with telco broadband as fiber penetrates deeper towards the home, so that distinction will over time disappear.
There will be a continuing demand for satellite transmission for the foreseeable future because of its coverage and reach, but it will be used increasingly for over-the-top rather than, say, direct-to-home (DTH) services. Indeed, we saw evidence of this at IBC 2019 with Newtec, which specializes in equipment for satellite communications, bullish about prospects for its partnership with DVB over future universal OTT services. The DVB demonstrated use of Newtec’s MCX7000 Multi-Carrier Satellite Gateway as a receiver for a single hybrid offering featuring its emerging DVB-I standard designed for delivery of all content over IP.
The DVB has seized that baton with DVB-I, whose main distinction is that it will enable delivery of all TV services over IP, including linear. Services can still be hybrid but all within the IP domain, enabling connected and broadcast devices to coexist without any need for software or firmware upgrades. So a tablet without a broadcast connection would be automatically routed to the Internet, while a TV or set-top lacking a broadband connection would be connected to broadcast over IP, all enabled via the DVB-I service list.
DVB-I then clearly represents the future for broadcasters as they seek more efficient and tighter integration between linear and on-demand content, so that users are totally unaware of any distinction. As IP becomes the standard for video distribution, fiber infrastructure and 5G networks will combine to handle the massive increase in media data traffic generated by proliferation in mobile video consumption.
This will not mean the end of satellite and in effect DTT will live on too, under the guise of multicast overlays on top of the cellular infrastructure through the High-Power High Tower (HPHT) model, on trial in various places including the German state of Bavaria. That is part of a substantial European 5G field trial investigating large-scale TV broadcasting in the FeMBMS mode over 5G networks. This is otherwise known as LTE Broadcast, which has been reinvented confusingly under the same name as a previous incarnation involved in various lackluster trials by Verizon among others.
At any rate HPHT can be regarded as DTT reinvented in all but name, using the same OFDM and associated Single Frequency Networks (SFN) operations. The principle of the OFDM/SFN coupling is simple – signals, or symbols, representing data bits, are split across multiple carrier waves, which means that components can be given longer in transit and therefore have greater time spacing between them. This reduces interference between the signals and allows greater robustness, making it easier to receive each part accurately while maintaining the same throughput. This greater spacing in turn allows neighboring transmitters to work in the same frequency, or SFN mode, without the offsets in RF transmission time causing interference. As a result, several adjacent transmitters send the same signal simultaneously at the same frequency, generating stronger more robust signals through constructive interference between them.
In parallel with HPHT will come multicast adaptive bitrate (ABR) for efficient distribution of linear content over IP, whether to mobile or fixed devices. The DVB has taken this in hand as well under the ambit of DVB-I, with work designed to address scaling issues and to avoid need for any adaptation at the client end. This part of the standard is due out in February 2020.
The point is that multicast ABR will terminate typically in some edge server relatively close to the client, saving upstream bandwidth by only delivering a single stream to each one. But if these edge servers are attached to content delivery networks that already employ hierarchical caching to minimize bandwidth, it may be that the business or technical case for multicast ABR will not stack up. However, it looks like the tide towards multicast ABR is becoming unstoppable and the DVB’s standard will help clear the way.
This migration towards all-IP will also help usher in personalized services and targeted advertising, with ability to harness customer data more effectively. This does though raise the question of how services will be regulated in this new IP era, which will determine the extent to which service providers can exploit customer data for example, as well as the degree of consolidation that will be permitted in this new world.