The Society of Broadcast Engineers Wishes to Thank the Advanced Television Systems Committee for Their Help in Organizing This Webinar

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The Society of Broadcast Engineers wishes to thank the Advanced Television Systems Committee for their help in organizing this webinar.

With these online, self-study courses, you pick the date, time and location to learn. Now that’s convenience! The cost for these courses varies from $59 to $99 for SBE Members.

Once you register for the course, you immediately receive a link to the course where you can access it again and again as your schedule permits. More Information: www.sbe.org

Webinars by SBE addresses specific subjects of interest to broadcast engineers. You can view the webinars live, or choose to view the recording on our website. Next Webinar: FCC Self-Inspection Checklist with Dennis Baldridge, Alternative Inspector November 18

More Information: www.sbe.org

1 Additional upcoming ATSC events… ATSC Mobile DTV Seminar October 7th, 2010 Wiley Rein Conference Center – Washington, DC ATSC Next Generation Broadcast Technology Symposium October 19th, 2010 Westin Hotel – Alexandria, VA For more information on these events and to register to attend, visit www.atsc.org

Thank you to the Society of Broadcast Engineers for inviting us to participate in today’s webinar!

Physical Layer for ATSC Mobile DTV Wayne E. Bretl Zenith Electronics LLC

Advanced Television Systems Committee

Three Views…

• Layers and sub-layers • Processing steps • Hardware Partitioning (Jay Adrick’s presentation)

Advanced Television Systems Committee

2 Layers and Sub-Layers

Advanced Television Systems Committee

ATSC Mobile DTV Layered Design

Presentation Layer Audio and Video Codecs Closed Captioning Management Layer TtTransport Streaming and Non-Real Time File Transfer Electronic Service Guide Physical Layer RF Transmission and Forward Error Correction; Compatibility with Legacy 8-VSB Receivers/Decoders

Advanced Television Systems Committee

Physical Layer Primary Requirements

• Mobile reception – Receivable under high speed mobile conditions (rapidly changing multipath) – Bursted transmission (receiver power saving) • Threshold – Low S/N threshold (for rapid fading conditions) • Backwards compatibility – Divide the broadcaster’s bandwidth flexibly into a variable-size Mobile DTV part and a complementary legacy DTV part, without disturbing the legacy reception – Versioning mechanisms

Advanced Television Systems Committee

3 Physical Layer - the Sub-Layer View

Advanced Television Systems Committee

ATSC M/H Layer Stack - Physical

Completely New in ATSC Mobile

Additional Training TPC FIC M/H Payload FEC (SCCC) Sequences

ATSC 8-VSB

Advanced Television Systems Committee

ATSC M/H Layer Stack - Physical

Completely New Acronyms Deciphered in ATSC Mobile

Additional Transmission Fast Mobile/Handheld Payload Training Parameter Information Forward Error Correction Sequences Channel Channel (Serial Concatenated Convolutional Coding)

Advanced Television Systems Committee 8-Level Vestigial Sideband Modulation

Advanced Television Systems Committee

4 Backwards Compatibility

•Legacy receivers must not see the new mobile signal as anything but normal (although unrecognized) data •New signal features for mobile that are logically stacked above 8-VSB, must be physically embedded inside the 8-VSB signal via concatenated coding

Completely New in ATSC Mobile, but Hidden Inside Legacy 8-VSB symbols

Additional Training TPC FIC M/H Payload FEC (SCCC) Sequences

Advanced Television Systems Committee 8-Level Vestigial Sideband Modulation

Advanced Television Systems Committee

New Features

Serial Concatenated Convolutional Coding - improved error correction and S/N ratio for mobile data

Additional Training TPC FIC M/H Payload FEC (SCCC) Sequences Advanced Television Systems Committee 8-Level Vestigial Sideband Modulation

FtIfFast Informati on Training sequences Transmission Parameter Channel ~ 800 per second Channel – extra-robustly coded - known symbols – extra-robustly coded - carries FIC data that - measure multipath - tells the mobile receiver tells the mobile receiver - support reception how much mobile data where each mobile at vehicular speeds is present and where it is program is located hidden in the legacy stream in the mobile data stream

Advanced Television Systems Committee

Time Multiplexing - Bursted Transmission

•The hidden mobile data is not constantly present. •Each mobile service/program has a series of time Slots within a mobile DTV Frame (968 ms) where it appears •The mobile receiver front end may be turned on only for the desired service

Advanced Television Systems Committee

5 Time Multiplexing – “Parades” of “Groups”

Legend: Mobile “Frame” = 968 ms Parade # 0 Parade # 1 Sub-Frame Sub-Frame Sub-Frame Sub-Frame Sub-Frame Parade # 2 #0 #1 #2 #3 #4 Legacy only 16 “Slots” - Each Slot contains all legacy data or some legacy data plus a Group of mobile data TUNER Slot ON TUNER Receiving: OFF Parade #0

Parade #1

Parade #2 Each Parade carries an “Ensemble” of programs with the same FEC code. The receiver tuner turns on only for the Parades it needs for a service

Advanced Television Systems Committee

Processing Steps

Advanced Television Systems Committee

Improvements … Required for Mobile

• Response to rapidly changing ghosts – 8-VSB reception fails above a few miles per hour in terrestrial vehicles – need highway speed

• Signal-to-Noise Ratio – Improve resistance to signal fading

• Do this while maintaining backwards compatibility and providing new features (higher layers) to support the mobile service (e.g., power saving, IP carriage, service guide…)

Advanced Television Systems Committee

6 ATSC Mobile Physical Layer Steps

1 Make Space for the Mobile Data 2 Add FEC coding bytes

3 Add SCCC Coding (1/2-rate or ¼-rate) 4 Interleave ((qrequired b ygyy legacy receivers ) 5 Add Training signals

Advanced Television Systems Committee

Comparison: 8-VSB Only vs. With Mobile

ATSC 8-VSB ATSC Mobile MPEG Reserve Some Packets 1 Packets for M/H Data Add RS 2 M/H Data with FEC Bytes Add’l FEC Bytes Interleave 3 Interleave Data Segments 8-Level with Trellis -Coded 4 SCCC or 8-Level Symbols Frame Trellis Coding Sync 313 M/H Frame Sync Data Payload (Reference Segment 312 Seg- DATA Training Sync ments SEG- Added Signal) ( ~ 25 8-VSB 5 and Segment MENTS msec ) PAY- Training Syncs LOAD

Advanced Television Systems Committee

1a Make Space for M/H “Slots” and “Groups”

ATSC 8-VSB ATSC M/H MPEG 1a Reserve Some Packets Packets for M/H Data

118 PACKETS

~ M/H or MAIN “Slot” of 24 msec 24 156 packets Data Field of 38 PACKETS “MAIN” MAIN ONLY 312 MPEG-2 (8-VSB) Packets DATA 118 PACKETS “Group” of M/H or MAIN 118 M/H Packets 38 PACKETS (if Slot is used) MAIN ONLY

Advanced Television Systems Committee

7 1b Organize into “M/H Frames”

TIME 1 M/H Slot = 156 TS Packets (approx 12.1 ms) 1 M/H Frame = 80 Slots (approx 968 ms)

Advanced Television Systems Committee

1c Per Program: Form “Parade” of “Groups”

MP H frame Parade #0

MP H Su b-Fra me MP H Sub -Frame MPH Su b-Frame MPH S ub-Fra me MP H Su b-Fra me Parade #1 #0 #1 #2 #3 #4

Parade #2

Symbol domain (after data interleaver) Slot Slot Slot Slot Slot Slot Slot Slot Slot Slot Slot Slot Slot Slot Slot Slot #0 #1 #2 #3 # 4 #5 #6 #7 #8 # 9 #1 0 #11 #12 #1 3 #1 4 #15

Power ON Receiving Power OFF Parade #0 (o r S lee p)

Receiving Parade #1

Receivinga Parade #2 Each Parade carries an “Ensemble” of programs with the same FEC code. The receiver tuner turns on only for the Parades it needs for a service

Advanced Television Systems Committee

2 Add FEC Bytes for M/H Data

“RS Frame” contains N all data in one Parade (for 968 msec) 187 Payload “N” columns (187+P,187) RS encode column-by-column 187 Add RS Bytes Payload Rows to Columns of Bytes P RS parity P = 24, 36, or 48

Add 2-byte CRC checksum row-by-row

Pack left to right and CRC checksum Payload Add Two CRC top to bottom with 187+P Bytes M/H header and IP RS parity per Row packets – wrap as necessary N+ 2

(Then add legacy 8-VSB headers and legacy RS bytes)

Advanced Television Systems Committee

8 3 4 5 SCCC Coding, Interleaving, Training

As broadcast BEFORE interleaving, with AFTER interleaving, with Training Signals segmented Training Signals aligned MAIN DATA

M/H GROUP #1 DATA + Interleaved Training SB Data Field SB Data Data Segments NING M/H Data I

M/H GROUP #9 V

is 8- DATA 313

TRA + Interleaved Training SCCC Coded

M/H GROUP #5 DATA + Interleaved Training Main Data is 8-VSB Data Field Data 8-VSB 312 Data 312 Data Packets Trellis Data Packet of Bytes Coded Data Segment of Symbols

Advanced Television Systems Committee

Test Experience

Advanced Television Systems Committee

Lab Results

8-VSB M/H M/H M/H M/H (A/53) (A/153) (A/153) (A/153) (A/153) ½ rate ½ rate mixed rate ¼ rate (Regions A+B)

SNR 15 7.4 7.9 7.3 3.4 Required (dB)

Doppler (Hz) ~= ~ 10 150 80* 140 180 max mph, with (depends on complex ghosts receiver) (TU-6)

*Note: 60 Hz is sometimes quoted as minimum adequate rate (DVB, others)

Advanced Television Systems Committee

9 Multiple Field Tests

• 2006 Lincolnshire, Illinois • Columbus, Ohio • 2007 Buenos Aires, Argentina • Santiago, Chile • 2007-09 Chicago, Illinois – two different broadcasters • 2008 Las Vegas, Nevada – four different broadcasters • San Francisco / San Jose, California – four different broadcasters • Raleigh, North Carolina • Dallas, Texas • 2009 Baltimore, Maryland • Denver, Colorado • Mexico City, Mexico • Milwaukee, Wisconsin – UHF and VHF • Atlanta, Georgia – two different broadcasters • Seattle, Washington – two different broadcasters • Washington, DC – six different broadcasters

Advanced Television Systems Committee

Detailed Field Test Results

Washington DC 5 different channels Data recorded simultaneously

Advanced Television Systems Committee

Washington, DC Channel 34

GOOD ERRORS NO DATA FOR THIS CHANNEL

Advanced Television Systems Committee

10 Washington, DC Channel 35

GOOD ERRORS NO DATA FOR THIS CHANNEL

Advanced Television Systems Committee

Washington, DC Channel 48

GOOD ERRORS NO DATA FOR THIS CHANNEL

Advanced Television Systems Committee

Washington, DC Channel 33

GOOD ERRORS NO DATA FOR THIS CHANNEL

Advanced Television Systems Committee

11 Washington, DC Channel 24

GOOD ERRORS NO DATA FOR THIS CHANNEL

Advanced Television Systems Committee

Thank You

Physical Layer for ATSC Mobile DTV Wayne E. Bretl Zenith Electronics LLC 2000 Millbrook Drive Lincolnshire IL 60069 [email protected]

Advanced Television Systems Committee

Transport / IP Rich Chernock , CTO Triveni Digital

Advanced Television Systems Committee

12 Advanced Television Systems Committee

Agenda

 Overview • Streaming Content • File Content • Summary

Advanced Television Systems Committee

ATSC Mobile DTV Architecture

Video Subsystem Video Video Source Coding MPEG and Compression

Audio Subsystem Audio Audio Source Coding Service and Compression Multiplex

Ancillary Data RF/Transmission MPEG 2 System Transport Control Data

ATSC Leggyyacy System M/H Framing Channel Coding

Video Subsystem

Video IP Video Source Coding Service Transport and Compression Modulation Multiplex RTP And Audio Subsystem

Audio IP Encapsulation Audio Source Coding and Compression

Ancillary Data Control Data IP/UDP (RTP) M/H Structure Data TPC/FIC ATSC Mobile / Handheld System

Advanced Television Systems Committee

13 Content delivery • DTV (mobile or fixed) is about delivering content to receiving devices – Streaming content • for example, linear television – File content – pushed BLOBs • ESGs • Non-Real Time content • Interactive components • … • Content delivery mechanisms for ATSC Mobile are different than for ATSC Fixed (mostly) – Aligned with mechanisms used for other mobile distribution systems – Key difference – IP rather than MPEG-2 TS based

Advanced Television Systems Committee

RS-Frame Internal Structure

N bytes

M/H TP header

Service #1 datagram

187 Service #2 row datagram s Service #3 datagram Stuffing

• Data transport is native IP, not MPEG-2 • RS-Frame row is called an M/H Transport Packet (TP) • IP Datagrams may wrap around from row to row, and from one RS- Frame to the next (except for NTP packets)

Advanced Television Systems Committee

IP Layer basics

• IP packets – IPv4 currently – Can migrate to IPv6 in future – No issue with # of IP addresses using v4 in broadcast environment – Multicast • UDP over IP – Key requirement – must operate in broadcast mode w/o return channel – TCP would not work well (or be necessary) • Remainder of stack depends upon content type

Advanced Television Systems Committee

14 Agenda

 Overview  Streaming Content • File Content • Summary

Advanced Television Systems Committee

What’s needed for delivering streaming content?

• Means to identify and segment/reassemble transport sized chunks of content from/to continuous streams  Transport • Means to synchronize content element streams  Timing model • Means to ensure sufficient space to hold content elements for decoding  Buffer model

Advanced Television Systems Committee

Streaming Delivery using RTP

• Real-time Transport Protocol (RTP) is today’s standard for delivering media over mobile networks – Enables services and content types to be transferred between other standards bodies such as the Open Mobile Alliance (OMA) to ATSC-M/H – Utilizes the wide array of encoding and delivery products optimized for the mobile market • RTP Packetizes audio and video frames into UDP over IP frames – RTP headers have timestamps and Stream ID unique to their streams. Note timestamps have a random offset from wall clock time – RTCP (Real Time Control Protocol) used to provide time base information – RFC 3550 – Replicates necessary functionality of MPEG-2 Transport • IP address/port replicates PID functionality • For “Broadcast Quality” a stringent timing/buffer model is necessary

Advanced Television Systems Committee

15 What is RTP: Encapsulation

• Real-time Transport Protocol encapsulates (RTP) elementary media streams directly into UDP packets with a RTP Header consisting of stream ID, timestamp and a few other fields

RTP Media Elementary Data Header

UDP Header

IP MTU: 1500 Bytes Header

IP Datagram 46

Advanced Television Systems Committee

How does ATSC-M/H use RTP

• ATSC-M/H uses Real-time Transport Protocol as specified in RFC 3550 with the following constraints – Packets may not be delivered out of order – RTP Sender Reports *should* be sent within 100 ms of a video random access point – A special ATSC-M/H timing and buffer model for RTP has been defined

Advanced Television Systems Committee

Core Philosophy of Audio Video Synchronization

System Time

Presentation Presentation Presentation Presentation Time Frame 0 Time Frame 1 Time Frame 2 Time Frame 3

Video Frame Video Frame Video Frame Video Frame

Audio Frame Audio Frame Audio Frame

Presentation Presentation Presentation Time Frame 0 Time Frame 1 Time Frame 2

Advanced Television Systems Committee

16 RTP: Synchronization

• RTP streams are synchronized via sender reports which relate the payload timestamp to the overall stream timebase – Stream timebases correlated by reference to NTP timebase – NTP timebase can be thought of as similar to PCR in MPEG-2 Systems

Video Port Video Elementary Data 40002 Timestamp

Video Sender Report: Port Timebase offset to 40003 master clock

Port NTP Timestamp NTP Timestamp 40010 Audio Port Timestamp Audio Elementary Data 40004

Audio Sender Report: Port Timebase offset to 40005 master clock 49

Advanced Television Systems Committee

Timing Model

• The ATSC-M/H timing model ensures that the timebase of the encoder can be recreated on the receiver – NTP Timestamps will be sent in a jitter-free manner as possible in addition to sender reports - Similar to MPEG-2 PCR

Video Sender Report: Port Timebase offset to master 40003 clock

Audio Sender Report: Port Timebase offset to master clock 40005

NTP timestamp to true client NTP timestamp to true NTP timestamp to true Port timebase client timebase client timebase 40010

Advanced Television Systems Committee

A/153 Timing Model Details

Physical Clock Decoder

Encoder Reference Clock

NTP Transmit Timestamps

RTCP SR bindings NIC NIC RTP timestamps

• Elements of timing model – “Borrowed” from MPEG-2 – Resolution, jitter, drift of encoder clock – Monotonically increasing NTP timeline w/o discontinuities (except rollover) – 90KHz resolution for video timestamps (audio at sample rate)

Advanced Television Systems Committee

17 A/153 Buffer Model

13818-1 Buffer Model

TBXV RBXV

TBV RBV EBn

TSX (i) TS

TBXAn

TB An Bn

• Buffer model established – Based on MPEG-2 principles – Takes into account bursty nature of A/153

Advanced Television Systems Committee

Agenda

 Overview  Streaming Content  File Content • Summary

Advanced Television Systems Committee

File Delivery

• The file delivery protocol is used to deliver the following file types: – Content (such as audio or video files) – Service Guide – Service Protection keys • The file delivery protocol does not specify how the files are used, that is up to the application.

Advanced Television Systems Committee

18 What is needed for file delivery

• Means to segment/reassemble large BLOBs • Means to distinguish between delivery “sessions” – Allows multiplexing deliveries on single transport • Means to manage “objects” – What’s contained in session? – What version – Other directory type information • Notions of carousels, updates, timing…

Advanced Television Systems Committee

File Delivery Specification

• IETF has standardized FLUTE for scalable delivery of files over a multicast IP link (RFC 3926) • OMA BCAST has specified a set of restrictions and clarifications to improve interoperability • A/153 Part 3 directly references the OMA BCAST File Delivery specification – With constraints applied

Advanced Television Systems Committee

FLUTE

• FiLe Delivery over Unidirectional Transport • Generally refers to a set of protocols including FLUTE, ALC (RFC- 3450) and LCT (RFC-3451) • FLUTE is used to deliver files over unidirectional network. • Feedback is not required, therefore – Suitable for broadcast – Scales well • FLUTE is the file delivery mechanism in – OMA-BCAST – DVB-IPDC – MBMS

Advanced Television Systems Committee

19 ALC / LCT

• FLUTE builds on top of ALC/LCT carried on UDP – ALC = Asynchronous Layer Coding – LCT = Layered Coding Transport • ALC / LCT provide the concept of Objects and Sessions • Can multiplex FLUTE sessions – Transmission Session Identifier (TSI) • Can support multiple objects per FLUTE Session – Transmission Object Identifier – “Table of Contents” called FDT (TOI==0) – FDT describes each file • Content location (URI) • TOI • Content-Length • Transfer-Length (may be the same if no FEC) • Content-Type (mime-type)

Advanced Television Systems Committee

Agenda

 Overview  Streaming Content  File Content  Summary

Advanced Television Systems Committee

Summary

• Streaming Content – RTP/UDP/IP – Specified timing model including use of NTP stream – Specified buffer model • File Content – FLUTE/ALC/LCT/UDP/IP – Support for sessions – Support for objects – NRT standard specifies functionality for things other than ESG, SP keys

Advanced Television Systems Committee

20 Thanks

Rich Chernock

[email protected]

Advanced Television Systems Committee

ATSC Mobile DTV Broadcast System IlImplement ttiation

Jay Adrick VP Broadcast Technology Harris Corporation, Broadcast Communication Division

Advanced Television Systems Committee

ATSC A/153 System Architecture

• ATSC A/153 standardizes the characteristics of the emitted Mobile DTV signal and describes the functionality that resides within the signal. – A/153 does not standardize the method of implementation – It does guarantee transmission to receiver interoperability

• The following description of ATSC Mobile DTV station implementation reflects the product architecture that is being developed by Harris and our team partners. • Other manufacturers may implement their products using another method. • Currently, there is limited interoperability between some manufacturers – Interface interoperability is under development in ATSC S5 activity – Harris equipment design reflects that activity

Advanced Television Systems Committee

21 Transmission System Pre-Processing

Legacy 8VSB Processing

Advanced Television Systems Committee

A/153 Transmission System

Mobile Network Adaptor Studio

STL Exciter

Transmitter

Legacy 8VSB Processing

Advanced Television Systems Committee

System Architecture - ATSC Only

Studio Transmitter ATSC PSIP STL Generator MPEG-2 TS IP

ATSC M ain Existing Channel ATSC ATSC Encoder(s) & Transmitter Exciter Service Multiplexer

Advanced Television Systems Committee

22 System Architecture with Basic ATSC Mobile DTV

Studio Transmitter ATSC PSIP STL Generator IP MPEG-2 TS

ATSC M ain Synchronous M2X MPEG-2 TS Channel Mobile Network Exciter ATSC Adaptor Encoder(s) & Mobile Multiplexer w/ M/H Transmitter System Time Generator Preprocessor Service Multiplexer Mobile Preprocessor SFN Processor

Mobile IP IP Channel IP Switch Encoder(s) IP

Signaling Generator Products Key

Electronic Service Transmission Products Guide (optional) Networking Products NRT Content Partner Products Station Manager/Server Third Party Supplied Metadata (optional)

Advanced Television Systems Committee

System Architecture with Advanced ATSC Mobile DTV

Studio Transmitter ATSC PSIP STL Generator IP MPEG-2 TS

Mobile IP IP Channel IP Switch Encoder(s) IP

Signaling Generator Products Key

Electronic Service Transmission Products Guide (optional) Networking Products NRT Content Partner Products Station Manager/Server Third Party Supplied Metadata (optional)

Advanced Television Systems Committee

System Architecture with Advanced ATSC Mobile DTV

Studio Transmitter ATSC PSIP STL Generator IP MPEG-2 TS

Mobile IP IP Channel IP Switch Encoder(s) IP

Signaling Generator Products Key

Electronic Service Transmission Products Guide (optional) Networking Products NRT Content Partner Products Station Manager/Server Third Party Supplied Metadata (optional)

Advanced Television Systems Committee

23 System Architecture with Advanced ATSC M/H & SFN

Studio Transmitter ATSC PSIP STL Generator IP MPEG-2 TS

ATSC M ain Synchronous M2X MPEG-2 TS Channel Mobile Network Exciter ATSC Adaptor Encoder(s) & Mobile Multiplexer w/ M/H Transmitter ATSC Time Generator Preprocessor Service Multiplexer Mobile Preprocessor SFN Processor M2X IP Mobile IP Exciter ATSC Channel IP Switch w/ M/H Transmitter Encoder(s) IP Preprocessor

Signaling Generator Products Key

Electronic Service Transmission Products Guide (optional) Networking Products NRT Content Partner Products Station Manager/Server Third Party Supplied Metadata (optional)

Advanced Television Systems Committee

System Architecture with Full ATSC M/H & SFN

Studio Transmitter ATSC PSIP STL Generator IP MPEG-2 TS

Service Signaling Generator Products Key Subscription Protection Electronic Service Manager Server/Encryptor Transmission Products Guide (optional) Networking Products (optional) NRT Content Partner Products Station Manager/Server Third Party Supplied Metadata (optional)

Advanced Television Systems Committee

ATSC Mobile DTV Encoder

• Function: Compresses and encodes audio/video program content into low bit rate IP packetized data streams for transmission to ATSC Mobile enabled receiving devices • Requirement: One encoder for each real time program stream that is to be transmitted over the ATSC Mobile DTV system. Redundancy should be considered at N:1 level • Detailed Specifications: – Video • Encoding format – MPEG4 h.264 base profile v1.3 • Resolution – 416 x 240 Progressive scanning • Aspect ratio – 16 x 9 (Wide Screen) • Source video – Could be 1080I, 720P, 480P (ws) or 480I (ws) – Recommended to start with 16 x 9 format or convert prior to encoding – Encoder should respond to AFD (Automatic Format Descriptor) • Closed captioning – CEA 708 format

Advanced Television Systems Committee

24 ATSC Mobile DTV Encoder

• Detailed Specifications cont’d: – Audio • Encoding format – HE AAC v2.0 (High Efficiency Advanced Audio Codec version 2.0) • Sampling Frequency – 16, 22.05, 24 KHz. with SBR & 32, 44.1, 48 KHz. w/o SBR SBR = Spectral Band Replication • Audio format – Mono or Stereo (capable of supporting parametric surround) • Source audio – AES digital – Discrete or imbedded – Output • Packetized IP over UDP (User Datagram Protocol) with RTP (Real- time Transport Protocol) • RTP supports: – Payload-type identification - Indication of what kind of content is being carried – Sequence numbering - PDU sequence number – Time stamping - allow synchronization and jitter calculations

Advanced Television Systems Committee

NetVX ATSC Mobile Encoder

NetVX platform incorporates modules for: • Mobile real-time stream encoding • Mobile IP encapsulation • Up to 4 encoders and encapsulator per frame • Video encoder includes 2 independent audio coders – enables additional audio only services • Also capable of ATSC encoding and multiplexing

Advanced Television Systems Committee

SynchronyMNA Synchronous Mobile Networking Adaptor

• Function: Multi function platform that supports preprocessing of the Mobile DTV data, multiplexing of the processed Mobile data into the ATSC transport stream, generation of FIC,TPC and Service ID signals, transmission of signaling tables, generation of ATSC system time and synchronization/timing adjustment of the ATSC transport for distributed transmission networking. The ATSC Mobile DTV processing and distributed transmission timing are each treated as an application . Three functional configurations are available: – ATSC Mobile Processing only – Distributed Transmission only – ATSC Mobile Processing with Distributed Transmission

The SynchronyMNA is a dedicated hardware platform using FPGA signal processing technology under the control of a microprocessor. It’s architecture allows for easy firmware and software updates.

Advanced Television Systems Committee

25 SynchronyMNA Synchronous Mobile Networking Adaptor

• Requirement: One system per station. Redundancy should be considered on a 1:1 level. Application options to be selected depending on system architecture • Detailed Specifications: – Inputs • SMPTE 310M/ASI (selectable) for ATSC Transport Input • Ethernet port for ESG, Signaling Generator, Content protection and NRT system • Ethernet ports for system configuration, monitoring and control • Internal GPS reference requiring an antenna – Outputs PC • SMPTE 310M/ASI selectable X 4

Advanced Television Systems Committee

APEX M2X ATSC Mobile Exciter

• Function: Generates ATSC 8VSB main service signal modulation while post-processing Mobile DTV content with RS coding, trellis coding, serial concantinated coding and training signals for enhanced Mobile DTV reception. • Requirement: One exciter per transmitter is required. Redundancy should be considered on a 1:1 level. • Detailed Specifications: – Inputs • SMPTE 310M or ASI Transport stream (selectable) • Internal GPS reference used for precise frequency, ATSC mobile and DTS (SFN) operation • External 10 MHz and 1 PPS reference (optional) • RF samples for RTAC adaptive correction • Ethernet for configuration, monitoring and control – Output PC • 8VSB modulated RF signal on assigned channel – .100 Watt maximum output power

Advanced Television Systems Committee

APEX M2X ATSC Mobile Exciter

Advanced Television Systems Committee

26 ATSC Mobile DTV Signaling, AtdBdAnnouncement and Beyond

Advanced Television Systems Committee

Service and Content Discovery

• Signaling – A/153 Part 3 – Fast Information Channel (embedded) – Service Signaling Channel (IP) – Essential information, required to • display services to the receiver user • play audio/video content • Announcement – A/153 Part 4 – Optional OMA BCAST Service Guide (IP) – Additional metadata for services and programs – Springboard for advanced services

Advanced Television Systems Committee

Signaling

Advanced Television Systems Committee

27 Service Signaling Channel

• Collection of binary tables – Transmitted as a well-known multicast UDP/IP stream – Different data is encapsulated in each ensemble • Service Map Table (SMT) MANDATORY – Describes services type, IP addresses, codecs … – May include current program information • Serv ice La be ling Ta ble (SLT) – Adds human-readable names to fast frequency scan • Guide Access Table (GAT) – How to acquire Service Guide, if present • Cell Info Table (CIT) – Supports service hand-off when roaming • Rating Region Table (RRT) – As in A/65

Advanced Television Systems Committee

Signaling - User Experience

• Media Plays! • Channel Info – Major, minor number – Short name – Service category (TV, Radio) – Typically scanned and cached • “What’s On Now” – Title – Genre, Rating, Duration – Available once tuned to ensemble • Others may not be populated or up to date

Advanced Television Systems Committee

Signaling Generator Integration

• System element responsible for constructing SSC tables – Tables (SMT) are dynamic with current program – Tables (SMT, SLT) must be sent once per M/H frame • A/153 does not standardize signaling to mux interface • Architectural choices for integration: – Monolithic integration with mobile mux/preprocessor – External IP stream generator - encapsulation in mux – External table loader - SSC carousel and scheduler in mux • E.g., approach used by Roundbox Broadcast Server and Harris SMNA

Advanced Television Systems Committee

28 Signaling Generator Functions

• Service Provisioning – Ensemble IDs – Service IDs and types – Component configuration • Metadata Collector – Program listings • TitanTV, Tribune, … • Program editor • Main channel PSIP ingest • PMCP integration • Table Generator – Creates tables and future schedule for upload to MNA – FIC built from data by MNA

Advanced Television Systems Committee

Announcement (Service Guide)

Advanced Television Systems Committee

Announcement

• OMA BCAST Service Guide (SG/ESG/EPG) • SG provides metadata for the broadcaster’s content that can be incorporated into a richer program guide • Basic features include – Delivery of channel icons – Complete program titles and descriptions , genre, ratings – Information for upcoming as well as current programs • Set of files delivered as FLUTE/UDP/IP streams • Signaled as a (hidden) non-A/V service – Discovery bootstrapped by FIC, GAT and SMT

Advanced Television Systems Committee

29 Announcement Relationship with Signaling

• Some overlap with Signaling layer: – IP multicast parameters – Title – Start time/duration – Genre category – Content advisory • When there’s conflictingg, info, receiver shall use Sig nalin g – Service Signaling Channel always takes precedence over Announcement • Signaling is mandatory, Announcement is optional • When used, it must be compliant with the following: – M/H Service Guide is compliant OMA BCAST Service Guide, as further constrained by A/153 Part 4 • More than one ESG is permitted – Receiver technology will support aggregation of guides

Advanced Television Systems Committee

Basic SG - User Experience

• Signaling experience enhanced • Richer channel info – Icon, URL, description • Richer program info – Description • “Wha t’s Com ing Up ” – Future programming for all channels on a broadcast • Amount may be tuned by broadcaster – Receiver aggregation • May be cached for all broadcasts

Advanced Television Systems Committee

Announcement Server Integration

• Element responsible for SG delivery • Architecture need not be as coupled to mux as signaling – External generation of FLUTE streams – IP streams encapsulated by mux • Common config and data with signaling generator – Service and component details – Program metadata • Typically shares hardware with signaling – E.g., Upgrade to Roundbox Server

Advanced Television Systems Committee

30 Announcement Server Functions

• Service Provisioning – Enhancement of signaling • SG Delivery Provisioning – FLUTE and IP parameters – Partitioning of guide data • Data type • Time window – Bitrate (per partition) – One or more SGs • Metadata Collector – Enhancement of signaling – Additional media delivery • Channel logos

Advanced Television Systems Committee

Broadcast Guide Configuration

• Strongly influenced by assumptions about receiver SG acquisition behavior • Acquisition of long-term guides (e.g., 7 days) – Second receiver? – Offline or manual scan and download? – Interaction channel? • Many receivers/apps have none of the above • Announcement server must be able to provide partitioned guide – Short-term to support “now and soon” programming – Long-term acquired during viewing (or scans, by more capable receivers)

Advanced Television Systems Committee

Additional Guide Scenarios

• A/153 supports signaling of SGs outside the current broadcast – Receiver can aggregate – Classical “time grid” views may only be realistic with market guide • SG from interactive channel – Likely the only common mechanism for market guide • SG from external broadcast – Requires multi-receiver or offline download device

Advanced Television Systems Committee

31 Advanced SG Features

• Richer information means the user spends more time in the guide or mobile TV application • Broadcaster opportunity for – Advertising and co-promotion – Interstitial content – Adjunct content delivery – Links to additional content – Interactivity • Broadcast SG can be a key enabler of additional content, if provided in a standardized way

Advanced Television Systems Committee

Mobile DTV Widgets

• Mobile DTV initial focus: Television services • Widgets add broadcast data services to the mix • Types: Global or Synchronized – Global: Not associated with a TV/radio service, e.g. news – Synchronized: Associated with and synchronized to TV channel/program, e .g . merchandising

Advanced Television Systems Committee

Non-Real-Time Content Delivery

• A familiar idea whose time has come? • Convergence of multiple factors: – Evolution of existing ATSC broadcast data standards – New classes of devices that are “DTVs” – Mobile DTV infrastructure relies on file delivery for SG – Similar efforts such as OMA DCD • ATSC NRT Standard – Applies to fixed and mobile ATSC – V1.0 in development in S13-1 AHG • Set of “modes” for push data • Extensible set of content types: media files, RSS, web bundles, … – Mobile: SG extensions to provide content guide – Standalone services - synchronized proposed in 2.0

Advanced Television Systems Committee

32 NRT Server Integration

• Element responsible for NRT Service Delivery • Service management – Service type, data source, Bandwidth configuration • Content ingest (e.g., RSS) – From local provisioning, broadcaster source or service bureau • Stream generati on – FLUTE/UDP/IP streams – Dynamic bandwidth management • Co-resident/co-located with Announcement Server

Advanced Television Systems Committee

Planning for ATSC Mobile DTV IlImplement ttiation

Advanced Television Systems Committee

Planning for Implementation

• Bandwidth Requirements

• Studio Facility Requirements

• Transmitter Requirements

• Optimizing Mobile Coverage

Advanced Television Systems Committee

33 Bandwidth Requirements

Main Channel Basics

• ATSC A/53 has 19.39 Mbps payload capability • The FCC requires all digital broadcasters to provide at a minimum 1 SD NTSC qqyuality free-to-air ppgrogram service • ATSC program guide (PSIP) requires about 0.5 Mbps

• Typical SD service in MPEG2 requires 2-4 Mbps

• Typical HD service in MPEG2 requires 10-14 Mbps

Advanced Television Systems Committee

Bandwidth Requirements

Mobile DTV Basics

• ATSC Mobile DTV channels are scaleable in number and level of robustness • Robustness is a function of coding level and it also drives payload efficiency – Half rate = 37% , Mixed rate = 26% , Quarter rate=17% • Streams with the same level of robustness (coding) can be assembled into an ensemble • Main channel contribution is made in increments – .917mbps, 1.83mbps, 2.750mbps, 3.667mbps, 4.584mbps 5.501mbps, 6.418mbps, 7.334mbps

Advanced Television Systems Committee

Bandwidth Requirements

Mobile DTV Basics

• Full details of bandwidth allocation for ATSC A/153 Mobile DTV can be found in the ATSC A/153 standards documents, Section 2 Page 63

• The following are some sample use cases that were detailed by OMVC members:

Advanced Television Systems Committee

34 ATSC Mobile Broadcast Scenarios

Assumptions

• VIDEO – Three Options High Quality Medium Quality Lower Quality 500 kbps 400 kbps 256 kbps

• AUDIO – Three Options

High Quality Medium Quality Lower Quality 32 kbps 24 kbps 16 kbps • CODING – Two Options

SCCC Outer Code SCCC Outer Code 1/4, 1/4, 1/4, 1/4 1/2, 1/4, 1/4, 1/4 Efficiency = 17.1% Efficiency = 26.4%

• Notes: – A range of 0 to 200 kbps is reserved for overhead (ESG, null bits, etc.), this value has been adjusted to try to optimize scenarios – The bit rate of still images is negligible for purposes of this document – NRT and other data delivery via M/H is not considered in this document – Refer to ATSC A/153 Section 2 Chart 6.1 for complete details

Advanced Television Systems Committee

Case 1 - One max-quality program

One max-quality program - 1/2, 1/4, 1/4, 1/4 Video bit rate 768 kbps Audio bitrate 24 kbps Overhead 176 kbps Total MH bandwidth 3.668 Mbps Remaining Legacy DTV Bandwidth 15.722 Mbps

One max-quality program - 1/4, 1/4, 1/4, 1/4 Video bit rate 768 kbps Audio bitrate 24 kbps Overhead 148 kbps Total MH bandwidth 5.502 Mbps Remaining Legacy DTV Bandwidth 13.888 Mbps

Advanced Television Systems Committee

Case 2 - One mid-quality program

One mid-quality program - 1/2, 1/4, 1/4, 1/4 Video bit rate 400 kbps Audio bitrate 24 kbps Overhead 60 kbps Total MH bandwidth 1.834 Mbps Remaining Legacy DTV Bandwidth 17.556 Mbps

One mid-quality program - 1/4, 1/4, 1/4, 1/4 Video bit rate 400 kbps Audio bitrate 24 kbps Overhead 46 kbps Total MH bandwidth 2.751 Mbps Remaining Legacy DTV Bandwidth 16.639 Mbps

Advanced Television Systems Committee

35 Case 3 - Two mid-quality programs

Two mid-quality programs - 1/2, 1/4, 1/4, 1/4 Video bit rate 800 kbps Audio bitrate 48 kbps Overhead 120 kbps Total MH bandwidth 3.668 Mbps Remaining Legacy DTV Bandwidth 15.722 Mbps

Two mid-quality programs - 1/4, 1/4, 1/4, 1/4 Video bit rate 800 kbps Audio bitrate 48 kbps Overhead 92 kbps Total MH bandwidth 5.502 Mbps Remaining Legacy DTV Bandwidth 13.888 Mbps

Advanced Television Systems Committee

Case 4 - Two high-quality programs

Two high-quality programs - 1/2, 1/4, 1/4, 1/4 Video bit rate 1100 kbps Audio bitrate 48 kbps Overhead 62 kbps Total MH bandwidth 4.585 Mbps Remaining Legacy DTV Bandwidth 14.805 Mbps

Two high-quality programs - 1/4, 1/4, 1/4, 1/4 Video bit rate 1100 kbps Audio bitrate 48 kbps Overhead 106 kbps Total MH bandwidth 7.336 Mbps Remaining Legacy DTV Bandwidth 12.054 Mbps

Advanced Television Systems Committee

Case 5 - Four mid-quality programs

Four mid-quality programs - 1/2, 1/4, 1/4, 1/4 Video bit rate 1600 kbps Audio bitrate 96 kbps Overhead 240 kbps Total MH bandwidth 7.336 Mbps Remaining Legacy DTV Bandwidth 12.054 Mbps

Four mid-quality programs - 1/4, 1/4, 1/4, 1/4 Video bit rate 1600 kbps Audio bitrate 96 kbps Overhead 185 kbps Total MH bandwidth 11.004 Mbps Remaining Legacy DTV Bandwidth 8.386 Mbps

Advanced Television Systems Committee

36 Case 6 - Two mid-quality programs + ten high & medium quality audio services

Two mid-quality programs and ten high-quality audio services - 1/2, 1/4, 1/4, 1/4 Video bit rate 800 kbps Audio bitrate of program 48 kbps Audio bitrate of audio services 320 kbps Overhead 284 kbps Total MH bandwidth 5.502 Mbps Remaining Legacy DTV Bandwidth 13.888 Mbps

Two mid-quality programs and ten high-quality audio services - 1/4, 1/4, 1/4, 1/4 Video bit rate 800 kbps Audio bitrate of program 48 kbps Audio bitrate of audio services 320 kbps Overhead 86 kbps Total MH bandwidth 7.336 Mbps Remaining Legacy DTV Bandwidth 12.054 Mbps

Advanced Television Systems Committee

Case 7 - High number of medium quality audio services

Reasonable upper limit of medium-quality audio services - 1/2, 1/4, 1/4, 1/4 = 155 Audio bitrate of audio services (32 kbps) 3720 kbps Overhead 153 kbps Total MH bandwidth 14.672 Mbps Remaining Legacy DTV Bandwidth 4.718 Mbps

Reasonable upper limit of medium-quality audio services - 1/4, 1/4, 1/4, 1/4 = 98 Audio bitrate of audio services (32 kbps) 2352 kbps Overhead 156 kbps Total MH bandwidth 14.672 Mbps Remaining Legacy DTV Bandwidth 4.718 Mbps

Advanced Television Systems Committee

Studio & Transmitter System Requirements

Advanced Television Systems Committee

37 Mobile System - Studio

• Equipment at Studio – NetVX Mobile Encoder System • 1 RU 3 Slot Frame or • 5 RU 17 Slot Frame

– Signaling Server • 1 RU Dell Server ChassisRoundBox ESG Server • Also support s ESG opti on

– IP Hub (Customer Supplied) RoundBox ESG Server

– SynchronyMNA Mobile Networking Adapter • 1 RU

Advanced Television Systems Committee

Signal I/O at Studio

• Transport Stream • RF – From ATSC main multiplexer to – GPS Antenna to SynchronyMNA SynchronyMNA input – Harris offers as option – could – From SynchronyMNA to STL be central antenna with DA input • IP Networks • SMPTE 310M preferred but will also support ASI – Mobile Program Content – Must be isolated network • Video • Encoder output(s) – SD Widescreen – Up to 5 per frame • SDI interface per mobile stream • Signaling Server output • IF HD – down convert to SD-WS • NRT Server (optional) • Audio • External IP delivered services – AES 48 KHz sample rate locked – Configuration & Control to video • IP port on each device – Discrete or imbedded • Preferred to support external access by permission

Advanced Television Systems Committee

Mobile DTV System Drawing

Advanced Television Systems Committee

38 Where in the transport stream

• The mobile system must be installed as the last item in the chain of equipment prior to the STL. – No additional multiplexing can be inserted after the mobile stream

• Common sources of problems are Nielsen NAVE encoders, rate shaping devices, transport processors (DTP), transport format converters (ASI to 310M) and some multichannel STL’s…if installed down stream of the mobile system

Advanced Television Systems Committee

STL Considerations

• Stable 19.39 Mbps STL link is essential • No drop or add of MPEG-2 packets allowed • SMPTE 310M interface is highly desirable between MNA output and exciter input • System has been tested over RF Microwave, Fiber and Copper links • Network to ASI or SMPTE 310M converters are known sources of stability problems • Some early digital RF link systems have known stability issues

Advanced Television Systems Committee

Mobile System - Transmitter

• Equipment at Transmitter – APEX M2X Exciter • Replaces existing ATSC exciter • Ideal configuration is transmitter with exciter change over system – Allows mobile installation without interrupting operations • 2 RU configuration is smaller than previous Harris ATSC exciters • Exciter requires external PC or lap top PC for configuration • Web GUI support remote configuration and monitoring (TBD)

Advanced Television Systems Committee

39 Signal I/O at Transmitter

• Transport Stream • IP Network – From STL or TS DA to exciter – Configuration & Control input • IP port on M2X • SMPTE 310M preferred but will • Preferred to support external also support ASI access by permission • RF • Local PC or Laptop to configure – GPS Antenna to M2X input • HiffHarris offers as op tion – could be central antenna with DA – RTAC RF Samples • Same as APEX • Sample ports to M2X inputs – 10 MHz Frequency Reference • Output available to support other plant requirements

Advanced Television Systems Committee

IP Management

• ATSC MDTV is a combination of transport stream, RF and IP technologies • Encoding, signaling, ESG, service protection, NRT delivery and multiplexing all require management of the IP domain • MAC and IP address management is essential and air critical • External access to Synchrony, Roundbox Data Server, NetVX and the M2X is very desirable and enables rapid troubleshooting and configuration – Access can be on a supervised basis

Advanced Television Systems Committee

Optimizing Mobile DTV Reception

Advanced Television Systems Committee

40 Understanding Mobile Coverage & Reception

• ATSC Mobile DTV reception is based on different planning factors than terrestrial DTV reception – Receive antenna height 45” vs. 30 ft. – Receive antenna gain -20db to -3db vs. 0db – System SNR 3.5 – 7.0db vs. 15db

• Field testing has shown that the “radio horizon” is the limit to reliable mobile/handheld coverage – Typically line of sight from TX antenna to receiver – Limitations typically are terrain and buildings – Flat terrain + tall towers + H&V pol + max power = 35 -45 mile coverage

Advanced Television Systems Committee

Targeted MDTV Coverage

• Broadcasters have indicated that they are most concerned with delivering coverage to: – Urban canyon areas – Interiors of large buildings – Urban areas that are terrain shielded

“Signal Saturation” vs “Coverage Contours” will become the principal criteria for successful performance

Advanced Television Systems Committee

Achieving Signal Saturation

• Circular polarization – Discussion to follow

• Maximized Power from main TX site – Achieved by low antenna gain and high transmitter power output

• Gap fillers and Repeaters – Synchronized or OTA

Advanced Television Systems Committee

41 Why Circular Polarization is Important

Polarization Mismatch Loss (Depolarization) Caused by misalignment between the transmit and receive antenna

3 PML dB

0 0 153045607590

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Why Circular Polarization is Important

Small scale fading occurs when multiple signals arrive at the receiver from nearby reflecting objects The vector addition of all multipath components create variations in the received signal strength Signal Power

Receiver Displacement

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CP results in improved signal availability

Signal Power dB Horizontal polarization 10

Mean 0

  18.7dB -10 98 % Service -20 0Receiver Displacement 180 360 20 Signal Pow Vertical polarization 10

Mean 0 e   19.7dB r dB -10

98 % Service -20 0Receiver Displacement 180 360 20

Signal Power dB Circular polarization 10

Mean 0   14.8dB -10 98 % Service -20 0Receiver Displacement 180 360

700 MHz

Advanced Television Systems Committee

42 Test Results Summary - UHF

8 O F S 6 W M F Circular Polarization O O I A 4 P O C L H E D E L O 2 N E U D B V S A U E Horizontal Polarization 0 E R A I H E R I -2 L A E C in Improvement (dB) D Vertical Polarization A I L -4 N E

Marg G -6

•On average, circular polarization offers 5 dB margin improvement over horizontal polarization •On average, circular polarization offers 7.5 dB margin improvement over vertical polarization

Advanced Television Systems Committee

Test Results Summary - UHF

Greatest Margin Occurs at 33% Vertical Component

6 Full CP

4 Optimum Range

vement (dB) 3 o

2 Horizontal Polarization Baseline

Margin Impr Margin 1 Vertical Polarization Baseline 0 0 102030405060708090100

% Vertical Polarization More than 4 dB of margin improvement with 20% < Vpol < 50%

Advanced Television Systems Committee

What about VHF?

Advanced Television Systems Committee

43 Results Summary - VHF

8 CPOL 6 O F S 4 W F M O O I A Circular Polarization P O C L 2 H E D E L VPOL O N E 0 U Horizontal Polarization D V Vertical Polarization B S -2 A E U E R A I H -4 E R L I in Improvement (dB) AED C -6 A I L

Marg N E -8 G -10

•On average, circular polarization offers 3.5 dB margin improvement over horizontal polarization •On average, circular polarization offers 4.5 dB margin improvement over vertical polarization

Frequency 210 MHz

130 Advanced Television Systems Committee

VHF Observations

• On a small handheld receiver, VHF provides: • Less polarization discrimination • Greater orientational immunity •“Omni Polarized” • On average circular polarization provided 3.5 dB of margin improvement over horizontal polarization

Great news for VHF….right?

Advanced Television Systems Committee

VHF Observations

Average Received Signal Strength UHF vs. VHF

Link Budget Differences Average Field Strength

VHF UHF UHF VHF Adjusted VHF

Antenna Gain ‐3.1 dB 0.0 dB Open ‐31.8 dBm ‐56.0 dBm ‐53.3 dBm

Tx Power ‐4.0 dB 0.0 dB Woods ‐38.2 dBm ‐55.7 dBm ‐53.0 dBm Tx Cable 3.6 dB 0.0 dB Office ‐45.2 dBm ‐72.0 dBm ‐69.3 dBm Rx Cable 0.5 dB 0.0 dB House ‐57.9 dBm ‐75.2 dBm ‐72.5 dBm Rx Ant. VSWR ‐9.5 dB 0.0 dB Vehicle ‐40.6 dBm ‐64.9 dBm ‐62.2 dBm Free space loss 9.8 dB 0.0 dB

Adjustment Factor ‐2.7 dB 0.0 dB Avg ‐42.7 dBm ‐64.8 dBm ‐62.1 dBm

VHF had 19.4 dB less average signal strength than UHF

Advanced Television Systems Committee

44 Small Receive Antennas

Harold Wheeler defined the fundamental limitations of electrically small antennas based on their size

~3” UHF Electrically small antenna – max dimension ≤ λ/2π ~8.5” VHF

3 Max power factor: P max = (ka)

a = antenna volume radius k = 2π/λ

Advanced Television Systems Committee

Wheeler Limit

Solve for the max power ratio difference between 210 MHz and 700 MHz

3  2    a  3         v  10log v    10log u    15dB  3     u   v  2      a  u  

Wheeler Limit dictates the best VHF/UHF receive ratio of an electrically small antenna will be -15 dB

Advanced Television Systems Committee

ATSC MDTV Repeater and Gap Filler Solutions

Repeater Applications

• On Channel rebroadcast of main station signal • Targeted coverage area is typically terrain isolated from main transmission point • Repeater coverage area is typically medium to large area • Signal source may be STL or “off air” depending on synchronization requirements

Advanced Television Systems Committee

45 ATSC MDTV Repeater and Gap Filler Solutions

Gap Filler Applications

• On Channel rebroadcast of main station signal • Targeted coverage area is typically terrain or structure isolated from main transmission point • Gap Fill er coverage area i s t ypi call y a small area and may be just the interior of a building or tunnel • Signal source is typically “off air”

Advanced Television Systems Committee

ATSC MDTV Repeaters

ATSC Repeater Solutions

Synchronized Non Synchronized Non Synchronized

SFN-Repeater Analog IF Gap Analog RF Transmitter Filler Gap Filler

MPEG-TS  RF1 RF1 Filter  RF1 RF1 IF-A  RF1

+ Performance 5 - Performance 1 - Performance 2 + Coverage 4 - Coverage 1 - Coverage 1 - Cost 5 + Cost 1 + Cost 2 + Error free output signal - Output limited by input SNR - Output limited by input SNR + Cascade/repeater possible - Requires very high I/O isolation - Requires very high I/O isolation + Same channel - Limited to very low power - Limited to very low power - Requires STL input - Adjacent channel issues - Adjacent channel issues - Coverage limited by interference + Good bit replication + Good bit replication from or to main TX

Advanced Television Systems Committee

ATSC MDTV Repeaters

ATSC RepeaterATSC Repeater Solutions Solutions - On Channel

Non Synchronized Non Synchronized Non Synchronized

Digital IF Gap Full Decode Gap Partial Decode Filler Filler Gap Filler

RF1IF-DAEC RF1 RF1MPEG-TS RF1 RF1Data RF1

Performance 3 + - Performance 1 + Performance 4 + + Coverage 3 - Coverage 2 + Coverage 3 Cost 3+ - Cost 4 - Cost 4 - Output limited by input SNR - Requires very high I/O isolation + Error free output signal + Able to run higher power - Limited to very low power + repeater chain possible + Good bit replication - Poor bit replication limits use for + Not SNR limited MDTV - Requires high I/O isolation + Not SNR limited -Limited to low power - Advanced Television Systems Committee

46 SFN Repeater Transmitter

RF1 out ATSC Up-Converter Modulator Amplifier

MDTV/SFN RF1 out ATSC Up-Converter Transmission Modulator Amplifier Adapter

Mode selection RS Coding 100% ATSC Compliant synchronization & Convolutional Error Free Signal Trellis state Coding

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Analog RF-Gap Filler

RF Level RF Level RF1 in RF1 out

RF Pre- RF RF Filtering Amplifier Amplifier

RF Pre-amplifacation Single Channel Post filter RF Filter RF Amplification

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Analog IF Gap Fill

IF Level IF Level RF1 in RF1 out

Down- Converter IF Unit Up-Converter Amplifier Filtering Amplifier

RF  IF Analog IF IF  RF conversion conversion Processing

Advanced Television Systems Committee

47 Digital IF Gap Filler

Digital IF Level Digital IF Level RF1 in RF1 out

Down- IF Unit Up-Converter Converter AEC Amplifier Filtering Amplifier

RF  IF Digital IF Adaptive Echo IF  RF Cancellation conversion conversion Processing

Advanced Television Systems Committee

Full Decode Gap Filler

MPEG-TS RF1 in RF1 out

ATSC A/53 ATSC Up-Converter Demodulator Modulator Amplifier

RF  IF  TS RS Coding ATSC Signal lacking Convolutional synchronization between Coding VSB & MH frames

Advanced Television Systems Committee

Partial Decode Gap Filler

MPEG-TS w/partial MH data RF1 in RF1 out

ATSC A/53 ATSC Up-Converter DdltDemodulator Modulator Amplifier w/ partial MH

RF  IF  TS RS Coding 100% ATSC Compliant Convolutional A/153 Error Free Signal Coding

Advanced Television Systems Committee

48 Adaptive Echo Cancellation

• Adaptive Echo Cancellation (AEC): Compensation of unwanted echos due to feedback paths

Antenna isolation

Gap-filler gain

Gain Margin = Difference between the Antenna isolation and the Gap-filler gain

Advanced Television Systems Committee

Off Air Fed Gap-Filler for ATSC MDTV

• Problem: Feedback from TX- to RX-Antenna

– System may become unstable

– Ddtifttil(MERhih)Degradation of output signal (MER high)

– Ripple in spectrum of output signal

Advanced Television Systems Committee

Definition of Gain Margin

Antenna decoupling

(Ad)

Echo Level

(PE)

Output Level

(PO) Input Level

(PI)

Amplification (a = PO -

Advanced Television SystemsPI )Committee

49 Definition of Gain Margin

Input Level (PI)

Echo Level (PE = PO – Ad) Output Level (PO = PI + a) Antenna decoupling

(Ad) Amplification (a = PO – PI )

Gain Margin = PI –PE

Gain Margin = PI –(PO –Ad)

Gain Margin = PI –(PI + a – Ad) = Ad -a

Advanced Television Systems Committee

Gain Margin Example

PO1 10W = 40 dBm Harris ATSC AEC PO2 40W = 46 dBm up to 0dB Gain Margin AD: 60-80dB vs. +20 dB w/o AEC PI: -40dBm nominal

10W Example best case Antenna decoupling: OK

Gain Margin = PI –(PO1 –AD) = -40dBm – (+40dBm – 80dB) = 0dB

40W Example best case Antenna decoupling: NO

Gain Margin = PI –(PO2 –AD) = -40dBm – (+46dBm – 80dB) = -6dB

Advanced Television Systems Committee

Gap Fillers

• High input to output isolation is required • Signal in non synchronous to main station •Interference can occur if signals overlap •Ideal for shielded building coverage using leaky coax for antenna Main Transmitter •Gap Filler TX is usually very low power…under 10 watts

Booster Transmitter

Interference Zone

Main Site Main Site Coverage Coverage Booster Site Coverage

Advanced Television Systems Committee

50 Don’t Forget Redundancy

Redundancy = Reliability

• Plan for system redundancy from the beginning of ATSC Mobile DTV operation

Why: ATSC M obil e DTV serv ice is tru ly a w ire less business. If you are off the air or limited in power, your mobile viewers will be lost. No cable TV distribution will support your wireless viewer base.

Advanced Television Systems Committee

ATSC Mobile DTV Station Implementation Jay Adrick, VP Broadcast Technology Harris Corporation Broadcast Communication Division Questions?

Advanced Television Systems Committee