DVB-T2

Managing DVB-T2 Broadcast Managing DVB-T2 Broadcast Transmission Networks Transmission Networks

Nils Ahrens

Business Development Manager Broadcast

Asia / Pacific

AIBDMay 2011 | Manage DVB-T2 Transmission Networks | Nils Ahrens | 2

Agenda

l DVB-T and DVB-T2 Basics

l Comparison between DVB-T and DVB-T2

l DVB-T2 Configurations and Coverage

l DVB-T2 Measurements


DVB-T2: Benefits over DVB-TNew Modulation, FEC and Transmission modesl 30 - 60% More Bandwidth enables more HDTV, SDTV and IP services

Multiple Input streams (Physical Layer Pipes = PLPs)l Common (e.g. SI) Data and service specific (Video, audio) streams

l Independent and Flexible Operation with multiple service providers

Dynamically variable modulation and FECl Mobile (time/frequency sliced) and Fixed Services in same bandwidth

l Optimal bandwidth utilization for different service types

Direct Support for non-TS formats e.g. IPl No Transport Stream packetization overheadl Repeated (null packets) or common (SI) data need not always be sentl No conversion simplifies interoperability


DVB-T vs DVB-T2

DVB-T DVB-T2Modulation QPSK, 16QAM,64QAM QPSK, 16QAM, 64QAM,

256QAM

FEC Conv. Coding + RS

½,2/3,3/4,5/6,7/8

BCH + LDPC

½,3/5,2/3,3/4,5/6

Guard Interval ¼, 1/8, 1/16, 1/32 ¼, 19/256, 1/8, 19/128, 1/16, 1/32, 1/128

FFT Size 2k, 4k, 8k 1k, 2k, 4k, 8k, 16k, 32k

Scattered Pilots

8% of Total 1%, 2%, 4%, 8% of Total

Continual Pilots

2.6% of Total 0.35% of Total


DVB-T2 Capacity Improvements

DVB-T DVB-T2Modulation 64QAM 256QAM

FFT Size 2k 32k

Guard Interval 1/32 1/128

FEC 2/3 CC + RS(8%) 3/5 LDPC + BCH

Scattered Pilots 8% 1%

Continual Pilots 2.6 % 0.5%

P1/P2 Overheads 0% 0.5%

Bandwidth Standard Extended

Capacity 24Mbit/s 36.1 Mbit/s

4 MPEG-4 HDTV in one channel


DVB-T2: Physical Layer Frame

P1: 1K FFT Symbol Indicating Start of T2 Frame

P2: Indicate how (L1) and when (L2) PLPs are transmitted

Common PLP:l Contains data shared with multiple PLPs e.g. SI Tables

Type 1 PLP:l Sent in single “slice” once per T2-Frame

Type 2 PLP:l Sent in two or more “sub-slices” per T2-Frame

P1 P2

T2 frame

Common PLP‘s

Data PLP‘s type 1

Data PLP‘s type 2

Auxiliarydata

Dummy cells


DVB-T2: RF Enhancements

l Modulation 256 QAM

l Rotated & Q-Delayed Constellations

l Extended 32k carrier mode

I

Q

I

Q


Rotated and Q-delayed Constellations

Mod. QPSK 16QAM 64QAM 256QAM

Φ (degrees) 29.0 16.8 8.6 atan(1/16)

I

QQ

I


Basics of DVB-T Network

TS

out

Transmitter 1

1 pps 10 MHz

GPS

1 pps 10 MHz

GPS

Transmitter 3

1 pps 10 MHz

GPS

Transmitter 2

NetworkAdaptorSignal

Distribution

HD ENC

SD ENC

SD ENC

MUX

1 pps 10 MHz

GPS

SFN Adaptor

Headend

Modulation Parameter will be identical for all Programs

Example

•64 QAM, 2/3 FEC, 8k FFT, GI 1/4

SFN improves Frequency Efficency

SFN Adaptor provides „MIP“ for synchronising all Tx in a SFN

SI


Basics of DVB-T2 Network

TS

out

Transmitter 1

Transmitter 3

Transmitter 2

HD ENC

SD ENC

SD ENC

MUX T2- MI Gateway

Physical Layer Pipe

Headend

l Complete Transport Stream Mapped to one PLP (Physical Layer Pipe)

l Simple Structure with Constant Coding and Modulation for all programs


Basics of DVB-T2 Network

TS

out

Transmitter 1

Transmitter 3

Transmitter 2

HD ENC

SD ENC

SD ENC

MUX T2- MI Gateway

Physical Layer Pipes

l Services in Transport Stream Mapped to individual PLPs

l SI data on separate common PLP

l Variable Coding and Modulation for each PLP

PLP1,HD 256 QAM ¾

PLP2,SD 64 QAM 2/3

PLP3,SD 16 QAM 2/3

PLP0, Common SI Data

Headend


DVB-T2 recommended Configurations8MHz Channel, 32K FFT, 1/128GI, PP7

High Bitrate for 4 HDTV programs (MPEG4)

Good coverage for 2 HDTV programs (MPEG4)


Coverage I – DVB-TDVB-T , 64QAM, CR 2/3, Guardinterval ¼, Bitrate 19,9MBit/s

ERP: 30 kW – Reception Mode: Roof Top – Polarization: Horizontal

Antenna height: 245m – Vertical 8 stock bays


Coverage II – DVB-T2DVB-T2 , 256QAM, CR 3/5, 32k Ext, Guardinterval 1/128, Bitrate 36,1 MBit/s




Coverage Comparison DVB-T vs DVB-T2



Area

Almost identical

Bitrate

81% higher in DVB-T2


DVB-T2 Measurements I l DVB-T2 Measurements are more complex than DVB-T

PLP Cells before Time Interleaving

PLP Cells before De-Rotation

P1 Symbol

OFDM Cells before Frequency De-Interleaving

Examples


DVB-T2 Measurements IIl DVB-T2 Measurements are more complex than DVB-T

PLP Cells before Time Interleaving

PLP Cells before De-Rotation

P1 Symbol

OFDM Cells before Frequency De-Interleaving

Examples: BUT WHO CAN TELL WHICH ONE IS GOOD, ACCTEPTABLE OR BAD


Data Base

Network Management Centre Transmission Centre

Remote Client 1 Remote Client n

Signal Monitoring

MPEG Probe

MPEG ProbeMPEG ProbeMPEG Probe

MPEG Probe

Scheduling Statistics & LOGS

ReportGeneration


Simply Manage your Transmitter Network

Warning !Shoulder Attn

low

ALARM Tx1!MER low

MER = 25 dB


The added ValueHigh Availability of Transmitter Network by reducing Downtime

l Keep Network Availibility high l Verification of Service Level Agreements (SLA)l Keep and maintains the Quality of Service (QoS)

Immediate Action for Service Teams in case of Transmitter / Network Problems l Switching & Monitoring redundancy concepts (Headends,

Transmitters,Exciter or Power Amplifier Faults)l Maintain a SFN configurationl Easy Localization of Faults by ideal positioning of Monitoring Probes

Verifies and captures Quality of Service Data betweenl Content Provider l Broadcasterl Network Operator


Summaryl Modern Measurement & Monitoring Systems will:l Help to manage complex Networks & Technologies with a

wider flexibilityl Become smaller and have more processing powerl Have intuitive GUI (easy to use)l Cover a broad range of standards l Have new measurement features

l Engineers l Have to understand technologiesl Have to learn, understand and make correct interpretations from

measurement results l Have to understand system architectures

NO MEASUREMENT SYSTEM CAN TAKE OVER THIS JOB !


Thank you for your attention !

Nils AhrensManagerCustomer Solutionsfor Broadcast

Rohde & Schwarz InternationalOperations GmbHBusiness Development Asia/Pacific

P.O. Box 801460 • 81614 MunichMuehldorfstrasse 15 • 81671 MunichGermany

Phone: +49 89 4129-11468Fax: +49 89 4129-61468Mobile: +49 151 1455 3451

[email protected]

DVB-T2

Documents

Transcript of DVB-T2