Webinar: ATSC 3.0 Physical Layer and Data Link Layer Overview

ATSC 3.0 brings IP delivery to over-the-air TV marking a major change in delivery to the home. For the first time video, audio and other data is all delivered as network streams allowing services available to TV viewers at home to modernise and merge with online streaming services better matching the viewing habits of today. ATSC 3.0 deployments are starting in the USA and it has already been rolled out in South Korea for the XXIII Olympic Winter Games in 2018.

Whilst the move to IP is transformational, ATSC 3.0 delivers a whole slew of improvements to the ATSC standard for RF, bandwidth, Codecs and more. In this, the first of three webinars from the IEEE BTS focussing in on ATSC 3.0, we look at the physical layer with Luke Fay, Chair of the ATSC 3.0 group and also a Senior Manager of Technical Standards at Sony.

Click to register: Wednesday, 15th January, 2020. 11am ET / 16:00 GMT

What is the Physical Layer?
The physical layer refers to the method data gets from one place to another. In this case, we’re talking about transmission by air, RF. Whilst this isn’t, in some ways, as physical as a copper cable, we have to remember that, at a basic level, communication is about making a high voltage in place A change the voltage in place B. The message physically moves from A to B and the medium it uses and the way it manipulates that medium are what we refer to as the physical layer.

In this webinar, Luke will talk about System Discovery and Signalling, defined by document A/321 and the Physical Layer Protocol defined by A/322. Both freely available from the ATSC website. The webinar will finish with a Q&A. Let’s take a deeper look at some of the topics which will be covered.

Choice of modulation

ATSC 3.0 has chosen the COFDM modulation scheme over the previous 8VSB, currently used for first-generation ATSC broadcasts, to deliver data over the air from the transmitter. COFDM, stands for Coded Orthogonal Frequency Devision Multiplexing and has become the go-to modulation method for digital transmissions including for DAB, DAB+ and the DVB terrestrial, satellite and cable standards.

One of the reasons for its wide adoption is that COFDM has guard bands; times when the transmitter is guaranteed not to send any data. This allows the receiver some time to receive any data which comes in late due to multi-path reflections or any other reason. This means that for COFDM, you get better performance if you run a network of nearby transmitters on the same frequency – known as a Single Frequency Network (SFN). A transmitters signal from further away will arrive later, and if in the guard interval, will be used to re-inforce the directly received signal. This means that, counter-intuitively from analogue days, running an SFN actually helps improve reception.

Multiple operating points to match the business case
Another important feature of ATSC 3.0 at the physical layer is the ability to be able to choose the robustness of the signal and have multiple transmissions simultaneously using different levels of robustness. These multiple transmissions are called pipes. As many of us will be familiar with, when transmitting a high bandwidth, the signal can be fragile and easily corrupted by interference. Putting resilience into the signal uses up bandwidth either due using some of the capacity to put error checking and error recovery data in or just by slowing down the rate the signal is sent which, of course, means not as many bits can be sent in the same time window.

Because bandwidth and resilience are a balancing act with each one fighting against the other, it’s important for stations to be able to choose what’s right for them and their business case. Having a high robustness signalm for penetration indoors can be very useful for targeting reception on mobile devices and ATSC 3.0 can actually achieve reception when the signal is below the noise, i.e. a negative signal to noise ratio. A higher bandwidth service delivering UHD at around 20Mbps can be achieved, however, by using 64 instead of 16 QAM.

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Speaker

Luke Fay
Chairman, ATSC Technology Group 3,
Senior Manager Technical Standards, Sony Home Entertainment & Sound Products – America

Video: ST 2110 Test and Measurement Super Session

This IP Showcase super session consists of six presentation from six different vendors which focus on specific aspects of test or measurement that is unique for ST 2110 environment. It is worth noting that these are technology presentations, not product presentations.

The session is led by Willem Vermost from EBU. He describes what kind of issues we need to solve in a SMPTE ST 2110 environment in terms of testing and monitoring. He speaks about PTP accuracy, traffic shaping (SMPTE ST 2110-21) and SMPTE ST 2022-7 redundancy.

Next, Michael Waidson from Tektronix focuses on Precision Time Protocol (PTP) which is a cornerstone of synchronisation of IP media networks. He walks us through Best Master Clock algorithm, boundary and transparent clocks plus PTP fault finding. (You might also want to watch the Monitoring and Measuring IP Media Networks presentation by Michael which we recently published on The Broadcast Knowledge.)

Furthermore, Jack Douglass from PacketStorm talks about ST 2110-21 traffic shaping measurements. He also shows how to use network emulation tools for testing ST 2022-7 link redundancy (the same data is sent through two separate paths of network emulation that are synchronised together, then burst loss are generated using RTP sequence number, with the least important bit different on both paths).

The next speaker is Ståle Kristoffersen from Bridge Technologies. He focuses on live performance monitoring in a ST 2110 network – does the signal make sense? (IP headers, RTP headers, ST 2110-20/30/40 essences), do all of the signals arrive? (packet loss, monitoring packet loss on 2022-7 links), does the signal arrive on time? (late can be just as bad as a packet loss) amongst others.

Moreover, Kevin Salvidge from Leader shows the differences in monitoring in an SDI and an all-IP facility. He compares single essence per BNC with multiple essences per fibre, synchronous and asynchronous transport and causes for errors (cable loss and impedance mismatch vs error packet loss and network overload). He also emphasises the need for accuracy of PTP and explains how to measure it.

Last but not least, Adam Schadle from Video Clarity walk us through video / audio performance and quality methods. He shows how to use picture and sound quality objective tests to understand network behaviour.

The presentations are followed by Q&A session.

See the slides here.

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Speakers

Willem Vermost Willem Vermost
Senior IP Media Technology Architect
EBU
Michael Waidson
Application Engineer
Tektronix
Jack Douglass
VP Marketing and Business Development
PacketStorm
Ståle Kristoffersen Ståle Kristoffersen
Lead Software Developer
Bridge Technologies
Kevin Salvidge
European Regional Development Manager
Leader
Adam Schadle
Vice President
Video Clarity

Webinar: What Is SMPTE ST 2110 & Why Does It Matter?


Date: Tuesday, 5 June 2018, 18:00 BST, 12PM EST

The SMPTE ST 2110 Professional Media Over Managed IP Networks suite of standards is a major contributing factor in the movement toward one common internet protocol (IP)-based mechanism for the professional media industries. The foundation for SMPTE ST 2110 standards is Video Services Forum (VSF) Technical Recommendation for Transport of Uncompressed Elementary Stream Media Over IP (TR-03). The SMPTE ST 2110 standards suite specifies the carriage, synchronization, and description of separate elementary essence streams over IP for real-time production, playout, and other professional media applications.

In this free webinar from IEEE, you’ll gain the knowledge you need to help your company make the most of SMPTE ST 2110, a critical enabler of fully internet protocol (IP)-based operations.

Speakers:
Joel E. Welch, Director of Education, SMPTE
Thomas Bause Mason, Director of Standards Development, SMPTE

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