Satellite Communications B Spring Semester 2004-5 -Satellite Broadcasting- : Satellite Communications B Spring Semester 2004-5 -Satellite Broadcasting- -Professor Barry G Evans- EEM.scmB
Contents : Contents 1. Analogue TV Satellite Broadcasting
2. Digital Satellite Broadcasting (MPEG/DVB-S)
3. New DVB-S2 standard and IP Delivery
4. DMB
Analogue Satellite Broadcasting : Analogue Satellite Broadcasting F.M. Theory –S/NW versus C/N
DTH/Cable head systems
WARC Broadcasting Plan
MAC Systems
System model : System model
FDM/FM techniques : FDM/FM techniques
FM Transmission Formats : FM Transmission Formats
NB. FDM/FM being replaced . Digital IDR TDM/PSK/FDMA
Characteristics of Frequency Modulation (FM) : Characteristics of Frequency Modulation (FM)
FM Threshold Effect : FM Threshold Effect
FM Theory : FM Theory General
Quality objectives for television (CCIR Rec. 567-1 & 568) : Quality objectives for television (CCIR Rec. 567-1 & 568)
ITU-R Subjective Quality Service : ITU-R Subjective Quality Service Picture Quality Weighted S/N(dB)
5 (excellent) 46.6
4 (good) 42.3
3 (fair) 38.0
2 (poor) 33.6
1 (bad) 29.3
Base band signals television : Base band signals television
FM Theory : FM Theory Television
Analogue transmission techniques -SCPC/FM transmission of television- : Analogue transmission techniques -SCPC/FM transmission of television-
Analogue transmission techniques -pre and de-emphasis : Analogue transmission techniques -pre and de-emphasis Noise at the output of a FM demodulator has a parabolic power spectral density: higher frequency components get corrupted by more noise than the lower frequency components.
PREEMPHASIS increases the amplitude of high frequency components before frequency modulating the carrier.
DEEMPHASIS removes this ‘distortion’ at the receiver.
Communication techniques : Communication techniques
FM Theory : 15 KHz TEST-TONE APROACH For A 1v pk-pk Test Signal with fixed pattern Alternate Black-White lines, which is convenient
Test Signal – equivalent deviation 15KHz sinusoid T.T. FTPP (WP) is the combined weighting & pre-de-emphasis gain referred to the 15KHz point, which is different from the 0 cross-over value (see slide)
UNIFIED WEIGHTING
Note that a unified weighting defined over satellite. For S/N calc’s the noise is calculated
Is a top baseband of fm=5MHz. Then :
625 Line (WP) = 13.2 dB.
525 Line (WP) = 14.8 dB FM Theory Television
Video Weighting Factor : Video Weighting Factor Frequency characteristics of weighting networks for measuring continuous random noise
* Improvement by emphasis + weighting factor. (P+O) The CCIR specifies the identical S/N relating to the continuous random noise, for 525/60 and 625/50 systems. Namely, the S/N should be equal to or better than 53 dB for 99% of time and 45 dB for 99.9% of time (Recommendation 567). This Recommendation was adopted at the CCIR Plenary Assembly in 1978, and the former frequency characteristics of weighting networks which had been separately defined for different TV standards were replaced by a single set of characteristics to give unified S/N objectives. Figure below shows the unified curve as well as the former frequency characteristics of weighting networks.
TV via Satellite : TV via Satellite Example
Satellite TV – Over Deviation : Use BW narrower than Carson without excessive distortion
Inst. Frequency corresponding to PK-DVN is well outside the passband filters when the deviation is close to PK, the carrier is suppressed and a short burst of noise is generated –visible as spots.
BUT % time when carrier outside passband is small –but excessive O/D will cause deterioration Satellite TV – Over Deviation
Data sub-carrier : Data sub-carrier
TVRO Satellite TV : TVRO Satellite TV
Link Performance -Exercise : Link Performance -Exercise Fixed losses = 0.5dB
Antenna Pt.Loss = 1.4dB
System noise temp. (clear weather) = 22.3dB-K
Rain loss (99.5%) = 0.7dB
Rain temp. = 275k
Desired TV quality S/N = 42.3dB (CCIR Grade 4)
Video bandwidth = 5MHz
Pre-emp . weight gain = 13.2dB
Receiver bandwidth = 27MHz
Video deviation = 13.5 MHz (P-P)
Calculate the earth-station dish size required to obtain CCIR Grade 4 quality TV reception for 99.5% of the time.
TV TRANSMISSION : TV TRANSMISSION ATV link to TVRO from Astra
Calculate the C/No on the uplink. Is this significant?
Calculate the size of dish required to provide CCIR Grade 4 B/N=42.3dB assuming clear weather (make allowance for absorption, pointing loss, etc.) Video devn 13.5MHz p-p, W+P=13.2dB, fm=5MHz, B=26MHz
Produce a link budget table for the above
Produce another column in the link budget table to represent the case for 99.5% availability for which a fade of 0.84dB is derived form the CCIR model.
Model of a Broadcasting Satellite System : Model of a Broadcasting Satellite System
Broadcast Satellites: the WARC Plan Features : Broadcast Satellites: the WARC Plan Features Frequency Band 11.7 to 12.5GHz (Europe & Africa)
40 channels spaced at 19.18MHz
Orbital positions –generally a 60 spacing
Frequency modulation –deviation 13.5MHz/Volt, i.e. a bandwidth of about 27MHz
5 channels for each country
Circular polarisation
Sound –a single channel on a sub-carrier
Video –PAL or SECAM composite
BSS Planning in Europe (1/3) : BSS Planning in Europe (1/3)
BSS Planning in Europe (2/3) : BSS Planning in Europe (2/3)
BSS Planning in Europe (3/3) : BSS Planning in Europe (3/3)
ITU Region 1 Ku Band Frequency Plan : ITU Region 1 Ku Band Frequency Plan
The MAC/Packet innovation : The MAC/Packet innovation Time division multiplex components
MAC format options B-MAC, D-MAC, D2MAC : MAC format options B-MAC, D-MAC, D2MAC Time Division Multiplex (TDM) at baseband of time compressed TV signal analogue components and digital components (sound/data).
B-MAC: 4 level encoding of digital components
D-MAC & D2-MAC: duobinary (3 level) encoding of digital components. Rate divided by 2 with D2-MAC Chrominance
Luminance
Sound+data MOD MOD
TDM
RF TIME COMPRESSION TIME COMPRESSION TIME COMPRESSION
MAC format options C-MAC : MAC format options C-MAC Time Division Multiplex (TDM) at radiofrequency of time compressed TV signal analogue components and digital components (sound/data)
2. Digital Broadcasting : 2. Digital Broadcasting MPEG Compression Techniques
MPEG Packets
DVB-S Transmission
Topics to be covered : Topics to be covered Why compression?
MPEG-2 compression toolbox, including:
Temporal and spatial redundancy
Discrete Cosine Transform, DCT
DVB channel adaptation, including:
Forward error correction (FEC) encoding
Modulation and the effects of nonlinearity
Quality of service and picture impairments
Contribution and distribution
Why is compression necessary? : Why is compression necessary? ITU-R BT.601-5 specifies 27Msamples/s at 8bits/sample = 216Mbits/s.
MPEG-2 can deliver consumer quality video at ~1Mbits/s to 6Mbits/s.
Typical broadcast satellite transponders have 27-36MHz bandwidth, cost roughly £2-3m/year, and can carry 30-40Mbit/s OR one FM TV channel.
Transponder cost/channel is much lower for MPEG-2 compression than FM-TV.
Digital format allows many more applications.
Elements of a digital satellite broadcasting system : Elements of a digital satellite broadcasting system STUDIO Camera Tape Film File server Contribution Electronic Programme Guide (EPG) MPEG-2 Encoder Subscriber Management System Conditional Access System
Multiplexer
Modulator
MPEG-2 Encoder
MPEG-2 Video Compression : MPEG-2 Video Compression Toolbox for bit-rate reduction includes:
Removal of temporal redundancy: inter-frame compression
Removal of spatial redundancy (DCT): intra-frame compression
Quantisation of DCT coefficients
Variable length coding (VLC)
Temporal redundancy : Temporal redundancy Three classes of video frame:
I-frames, make no reference to other frames
P-frames, predicted from earlier I- or P-frames
B-frames, predicted from both past and future frames
Only P- and B-frames use temporal redundancy.
Temporal redundancy : Temporal redundancy Use motion estimation to predict the next frame.
Use DCT to encode the difference between predicted and actual. Intraframes Predicted frames
Spatial redundancy : Spatial redundancy Operates on blocks of 8x8 pixels.
Discrete Cosine Transform (DCT) converts spatial elements to frequency domain (lossless).
Scaling related to human vision’s perceptual sensitivity.
Quantisation controlled by feedback from rate buffer.
Spatial redundancy : Spatial redundancy Pixel values for
a block taken from
a typical picture Increasing horizontal frequency Values after
DCT processing Increasing vertical frequency
Spatial redundancy : Spatial redundancy Increasing horizontal frequency Increasing vertical frequency DCT values after quantisation and scaling:
Spatial redundancy : Spatial redundancy Conversion to serial data by zig-zag scanning: Run length coding removes long strings of zeros.
Variable length coding replaces common values with shorter symbols (c.f. Morse code).
Control of quantisation : Control of quantisation Buffer
occupancy Quantisation threshold Fixed rate Variable rate From DCT
process Data rate
control Quantisation of DCT coefficients Variable length coding Buffer store
MPEG audio : MPEG audio Uses a psychoacoustic algorithm based on the characteristics of the human hearing system.
Divides the audio spectrum into sub-bands.
The model determines the just-noticeable level of noise for each sub-band, and adjusts quantisation.
Loud sounds reduce the ability to hear quiet sounds at other frequencies, so the quiet sounds may not need to be transmitted.
MPEG system layer : MPEG system layer Elementary Stream: a stream of information that forms part of a programme, eg sound.
Programme Stream: a set of elementary streams having a common time base, that form a programme. A programme typically comprises video, associated sound channels, and data.
Transport Stream: a combination of one or more programme streams with one or more independent time bases, formed into a single stream. The transport stream is formed into packets of 188 bytes.
MPEG system layer : MPEG system layer Video encoder Audio encoder Data encoder Other programmes Other data Elementary
streams Programme
streams Transport
stream
Broadcast transmission - enter the DVB! : Broadcast transmission - enter the DVB! MPEG defines the Transport Stream but not how to carry it.
DVB defines framing structure, channel coding and modulation for satellite (DVB-S) in EN 300 421.
DVB is a European project, but DVB-S has been adopted around the world.
Channel adaptation : Channel adaptation Channel Adaptation: the processes involved in taking a Transport Stream and converting it to a form suitable for transmission on the satellite. Energy
dispersal Outer FEC
encoder Interleaver Inner FEC encoder Baseband shaping QPSK Modulation To RF channel Transport
stream
Energy dispersal : Energy dispersal Energy dispersal: intended to ensure that patterns in the data stream do not cause power spectral density peaks.
Achieved by exclusive-or with PRBS.
Outer FEC encoding : Outer FEC encoding Reed-Solomon (204,188) encoding adds 16 bytes to each MPEG packet.
Interleaver : Interleaver Interleaver: breaks up bursts of errors, so that the performance of the Reed-Solomon error corrector in the receiver is enhanced.
Achieved by changing the sequence of transmission of bytes, then performing the inverse function in the receiver.
Inner FEC encoder : Inner FEC encoder Provides a second layer of forward error correction.
Target BER in receiver after error correction is 10-11, corresponding to roughly one uncorrected error per hour.
Target BER can be achieved with channel BER<10-2.
Choice of code rates of 1/2, 2/3, 3/4, 5/6, 7/8 allows trading of bandwidth and error performance.
Modem performance : Modem performance DVB specifies modem performance in IF loop to achieve quasi error-free performance: Note: Eb/N0 = 10log(C/N0) - 10log(bit rate). The bit
rate referred to in this table is the useful bit rate before
RS encoding.
Modulation : Modulation Modulation cannot be AM because the satellite TWTA must operate at saturation to deliver maximum power.
Modulation must therefore be some form of phase shift keying (PSK).
Requirement for the smallest possible receiving antennas means that the modulation must be rugged, i.e. able to be demodulated at low C/N.
Must be spectrally efficient (bits/Hz) to maximise transponder payload.
Modulation : Modulation BPSK has largest inter-symbol distance.
QPSK has half BPSK’s symbol rate, so half the bandwidth. Inter-symbol distance is down 3dB relative to BPSK, but so is received noise power! I Q 0 1 I Q 0,0 1,1 0,1 1,0 BPSK constellation QPSK constellation
Baseband shaping : Baseband shaping Amplitude Nyquist
bandwidth Slow roll-off Medium roll-off Fast roll-off
Modulation performance : Modulation performance Typical receiver performance in a linear channel: Measured Theoretical Note: in this case
the bit rate used
to calculate Eb/N0
from C/N0 is the
channel rate.
Effects of nonlinearity : Effects of nonlinearity Modem performance is not significantly affected by TWTA nonlinearity, even at saturation, for a single carrier.
Note the effect of nonlinearity on the spectrum (next slide). It can have significant impact on the design of the uplink earth station, in order to meet adjacent channel interference (ACI) criteria.
Effect of TWTA on spectrum : Effect of TWTA on spectrum Spectrum of 11Mbits/s (gross rate) QPSK signal after passing
through a wideband TWTA at saturation.
Example payload calculation : Example payload calculation Q. 30MHz of bandwidth is available. If the inner code rate is 3/4, what is the bit-rate available to the MPEG stream?
A. The relationship between bandwidth at -20dB relative to mid-band and the symbol rate is
BW = 1.28 x symbol rate.
Therefore, symbol rate = 30 / 1.28 = 23.4Msym/s
QPSK has two bits per symbol, so the gross bit rate is 23.4 x 2 = 46.8Mbits/s.
Example payload calculation : Example payload calculation The rate after the inner layer of error correction is
46.8 x 3/4 = 35.1Mbits/s.
The rate after the outer (RS) layer of error correction is
35.1 x 188/204 = 32.3Mbit/s.
Quality of service : Quality of service The two concatenated error correcting codes give an abrupt failure as C/N degrades.
Above the failure point, picture quality is the same as that leaving the studio. Picture
Quality C/N FM Digital FM threshold Digital threshold
Picture impairments : Picture impairments Impairments are different from PAL (eg cross-colour).
Dependent on bit rate.
Dependent on picture content.
Rule of thumb: <2Mbits/s for talking heads at VHS quality, 6Mbits/s for high quality action sports.
Impairments are mainly due to detail being omitted, and in severe cases can lead to blocks becoming visible.
Broadcaster can trade picture quality with number of services.
Contribution and Distribution : Contribution and Distribution Broadcaster to broadcaster connections:
Programme exchange
Feeds to cable head-ends (primary distribution)
Digital Satellite News Gathering (DSNG)
DVB-DSNG (EN 301 210):
Specifies QPSK, same as DVB-S
Adds 8PSK and 16QAM
Links to IP delivery over MPEG/DVB-S & DVB-S-RCS : Links to IP delivery over MPEG/DVB-S & DVB-S-RCS Having a digital transport packet, PES, it is possible to load IP packets into these and thus deliver. IP over MPEG/DVB-S
As well as the forward channel MPEG/DVB-S a return channel –RCS –return channel via satellite- has been standardised –DVB-S-RCS.
These topics will be covered in an associated lecture (Dr Haitham Cruickshank)
DVB-DSNG Standard 1992 : DVB-DSNG Standard 1992 Upgrading DVB-S to satellite news gathering at contribution qualities
8PSK/16QAM with standard conv codes –spectrum eff. 3.2 bits/symbol
Allow smaller dish SNG to operate at higher C/N’s
3. New Standard DVB-S2 – 2003 : 3. New Standard DVB-S2 – 2003 Achieves 35-40% increase in throughput for same bandwidth
Greater than 20 combinations of modulation and coding schemes offer
Spectrum efficiency 0.54.5 bits/unit bandwidth
C/N from –216dB
Backward compatibility with DVB-S
Opens up range of new services and reduced costs
New Standard DVB-S2 – 2003 : New Standard DVB-S2 – 2003 Layered modulation
QPSK, 8 PSK, 16 APSK, 32 APSK
Low density parity check (LDPC)
Codes rates 1/4,1/3, ½, 3/5, 2/3, ¾, 4/5, 5/6, 8/9, 9/10
Concatenated scheme
Inner LDPC
Outer BCH
Modulation schemes DVB-S2 : Modulation schemes DVB-S2 The four possible DVB-S2 constellations before physical layer scrambling
Modulation schemes DVB-S2 : Modulation schemes DVB-S2 QPSK/8 APSK broadcast applications
16/32 APSK professional applications requiring higher C/N
Need pre-distortion in uplink to overcome non-linear.
Schemes better in non-linear channel cf. 16/32 QAM
Roll-off factors - =0.35, 0.25, 0.2
Modulation schemes DVB-S2 : Modulation schemes DVB-S2 Functional block diagram of the DVB-S2 system
Modulation schemes DVB-S2 : Modulation schemes DVB-S2 LDPC inner codes –simple block code (Gallager)
BCH outer coding removes the error floor (no interleavers)
FEC coded blocks (FEC frames) length 64800 or 16200 bits
Framing Structure: the system train : Framing Structure: the system train Pictorial representation of the physical layer framing structure
Framing Structure: the system train : Framing Structure: the system train Physical level: robust synch. and signalling
Physical train: sequences of periodic wagons (PL frames)
Within PL frame. M/C is homogeneous
With variable C/M –(VCM) –M/C changes in adjustment wagons
Framing Structure: the system train : Framing Structure: the system train PL frame =
Payload (64.800bits) – LDPC/BCH FEC + PL header (90 symbols) synch/sig. Mod. & coding type FEC rate, frame length, pilots, etc.
PL header –uses fixed /2 BPSK –7/64 block coded
Base band level
Configures Rx according to application
Single or multiple input streams, generic or transport stream
CCM (const. M/C)
ACM (adaptive M/C)
DVB-S2 Performance : DVB-S2 Performance Required C/N versus spectrum efficiency, obtained by computer simulations on the AWGN channel (idea demodulation) (C/N refers to average power)
Operates C/N’s –2.4dB with QPSK/1/4 to 16dB with 32APSK/9/10 (for PER of 10-7)
Note: 20-35% capacity increase over DVB-S
DVB-S2 Range of C and M : DVB-S2 Range of C and M Examples of useful bit rates Ru versus LDPC code rate per unit symbol rate Rs
Comparison DVB-S and S2 (CCM) : Comparison DVB-S and S2 (CCM)
New standard DVB-S2 – 2003 : New standard DVB-S2 – 2003 Standard optimised for range of satellite transponder characteristics and satellite channels
Variable coding and modulation allows change on frame to frame basis
Allows MPEG2, MPEG4, IP and ATM input streams
Adaptive M&C can be operated between forward/return (RCS) to secure 4-8dB added advantages
Using ACM for IP Unicast (1) : Using ACM for IP Unicast (1) Block diagram of a DVB-S2 ACM link
Rx means C/N+I and reports to G.W.
GW adapts M and C on frame basis
Ka-band needs ACM to compensate fades 0.5dB/s –leads to around 1dB accuracy corrections.
Using ACM for IP Unicast (2) : Using ACM for IP Unicast (2) Example of IP services using a DVB-S2 ACM link
Using ACM for IP Unicast (3) : Using ACM for IP Unicast (3) ACM routing manager –separates the IP pkts/user per required protection and per service level and can prioritise per service.
Single streams –ACM router and DVB-S2 mod independent and can implement any routing policy.
Multiple streams –ACM is active and selects and prioritises packets as well as delaying for prioritisation.
New standard DVB-S2 – 2003 : New standard DVB-S2 – 2003 Delivery HDTV and IP services
Combining DVB-S2 – MPEG4, ACM schemes get 25 video channels in 33MHz transponder
DVB-S2 and ACM with multispot Ka-band satellites and DVB-RCS
reduce IP delivery costs by factor 10
Compatible cable/fibre costs
DVB-S2 has backward compatibility but will take time to replace large number of home decoders
DMB – Digital Multimedia Broadcasting : DMB – Digital Multimedia Broadcasting DMB and multicasting to mobile terminals is a major new market.
Forecasts for MB market in 2008
90 million users worldwide
80 B € revenue
Satellite can play major role (SDMB,MBSAT) but terrestrial options. (DAB, DVB-H).
DMB: convergence of different worlds : DMB: convergence of different worlds
DMB services: real-time vs non real-time : DMB services: real-time vs non real-time RT: real-time broadcast/multicast to mobile terminal
Live TV
Live music
Information (news, traffic)
Advertising
Webcams
Multiplayer gaming
Emergency messages
NRT: non-real time, content stored on terminal and consumed later
Video on-demand
Music on-demand
Webcasting
Web-browsing
Personalised content
Video games
Content for Mobile TV : Content for Mobile TV Existing TV content cannot be directly transported to mobile terminals
“Mobile TV is not TV on the mobile”
Content adaptation strategies are necessary
Small screens
Detail-driven source coding
Content trasducers
New content produced for mobile TV
Short sequences (1 to 15 mins typical)
NAVSHP (Networked Audio Visual Systems and Home Platforms)
New media technology platform for EC IST FP7
Thomson, Alcatel, ST, Siemens, Nokia, Philips, Intel
New Media Council: next meeting Dec 2-3, 2004.
DMB systems : DMB systems Classification is difficult, due to large overlap
Criteria
Coverage: terrestrial/satellite
Terminals: handset/vehicular
Target service: audio/video/multimedia
World region of operation
Integration with cellular networks
In operation/planned
Standard/proprietary air interface
Examples
Digital Audio Broadcasting (e.g. DAB, XM radio, Sirius)
Digital Video Broadcasting (e.g. DVB-T, DVB-H)
MBSAT
IMT2000 (e.g., UMTS-MBMS, S-DMB)
…
DMB systems : DMB systems Classification is difficult, due to large overlap
Criteria
Coverage: terrestrial/satellite
Terminals: handset/vehicular
Target service: audio/video/multimedia
World region of operation
Integration with cellular networks
In operation/planned
Standard/proprietary air interface
Examples
Digital Audio Broadcasting (e.g. DAB, XM radio, Sirius)
Digital Video Broadcasting (e.g. DVB-T, DVB-H)
MBSAT
IMT2000 (e.g., UMTS-MBMS, S-DMB)
…
DAB : DAB Standardized by ETSI in 1995
Replacement for analog AM and FM
MPEG2 audio layer II
Enhanced data services
N x 24 ms Frames, DQPSK, OFDM
1/4 - rate Conv. Code, Interleaving, Puncturing
4-Modes of Operation
Deployed in >35 Cntrs. Around the world
DARS systems: XM radio : DARS systems: XM radio DARS = Digital Audio Radio Service
XM Satellite Radio (CONUS)
started in 2001
A $1,5 billions program targeting vehicular market
100 Thematic radio channels, FM+ quality
$10/month subscription
Receivers price starting today from $120
XM exceeded 1 million customers end of October 2003
Constellation
2 GEO satellites
Terrestrial repeaters (~1500)
Air interface
QPSK TDM
S-Band
DARS systems: Sirius : DARS systems: Sirius Sirius (CONUS)
Started 2002
120 Thematic radio channels, FM+ quality
$12.25/month subscription
400K users end of June 2004
Member of ASMS-TF
Constellation:
3 HEO sat
Terrestrial repeaters (~ 90)
Air interface:
Direct link: QPSK TDM
Terrestrial repeater link: QPSK COFDM
Coding: RS+Conv
Sat diversity
MBSAT : MBSAT MBSAT (Japan and Korea)
opening 2004
1 GEO sat, 12 m antenna
Gap fillers
25 MHz band at 2,6 GHz, 7 Mb/s capacity
Vehicular and pedestrian usage
10 TV and 50 Radio broadcast programs
Target 20 Million customers in 2010
400 to 600 $ receivers
3 to 20$/month subscription
System Cost ~800 M$
Tens of thousands of terrestrial repeaters
Partnership: Toshiba, NTV, NTT, SKT, Toyota, Mitsubishi, Samsung,...
Strong involvement of SKT in Korea to market the MBSAT system
Targeting video over cellphone with Samsung products
DVB standards: DVB-T/H : DVB standards: DVB-T/H DVB-T has been standardized in 1997 and now deployed worldwide
DVB-T adopts QAM-OFDM
DVB-H is the evolution of DVB-T for broadcasting to mobile handsets
Targeting 2005 commercial product availability
Regulatory allocation for DVB-H Network is a big concern
Will require tremendous lobbying effort to grant VHF/UHF before 2010
DVB-H System overview (1) : DVB-H System overview (1) Objectives
Broadcast transmission to mobile handheld terminals of datagrams (IP or other datagrams) pertaining to multimedia services, file downloading services, etc
Constraints
Limited power supply (small terminals)
Varying transmission conditions (mobile terminals)
Systems specification
DVB-H = DVB-T +
4K OFDM mode
Enhanced interleaving for native DVB-T 2K and 4K modes
Time slicing
Enhanced signalling
Packet coding: MPE-FEC
5MHz bandwidth
Reference documents
EN 300 744: Framing structure, channel coding and modulation for digital terrestrial television (DVB-T), Appendix G and H specific for DVB-H
EN 301 192: Link Layer
EN 300 468: Service Information
TS 101 191: Single Frequency Network
DVB-T/H System overview (2) : DVB-T/H System overview (2) 4 bandwidth modes: 5, 6, 7, and 8 MHz
3 OFDM modes: 2K, 4K, 8K
3 modulation formats:
4-QAM
16-QAM
64-QAM
Hierarchical and non-hierarchical transmission
Non-hierarchical: constant error protection
Hierarchical: higher protection for basic information, lower protection for additional information
Bit-wise and symbol-wise interleaving
Concatenated channel coding
Inner code: convolutional code with 4 coding rates: 1/2, 3/4, 5/6, and 7/8
Outer code: RS code
DVB-T/H network layout : DVB-T/H network layout 4 kinds of frequency networks can be deployed
Large area SFN (Single Frequency Network) :
Many high power repeaters with large transmitter space
large delays large guard time required
Challenging transmitter synchronization
Regional SFN:
Few high power repeaters with large transmitter space
Large delays large guard time required
Simpler transmitter synchronization
MFN (Multi Frequency Network) with dense SFN around each MFN transmitter:
Medium power SFM transmitter with medium transmitter spacing
SFN gap fillers
Low power SFN transmitter with small spacing to fill gaps in coverage
Small delays small guard time required
DVB-T/H: functional block diagram : DVB-T/H: functional block diagram
DVB-T/H: MPEG-2 : DVB-T/H: MPEG-2 MPEG-2 transport multiplex packet:
188 byte: 1 synch word + payload
DVB-T/H: RS outer coding : DVB-T/H: RS outer coding
DVB-T/H: outer interleaving : DVB-T/H: outer interleaving
DVB-T/H: inner convolutional coding : DVB-T/H: inner convolutional coding
Mobile TV: the DVB-T/H technology : Mobile TV: the DVB-T/H technology Mobile terrestrial broadcast (DVB-H) is an “add-on” to the standard terrestrial broadcast (DVB-T)
Reuse of high power DVB-T transmitter + deployment of dedicated on-channel and frequency conversion repeaters
Additional FEC protection and introduction of Time Division Multiplexing
New service delivery “IP based” for flexible aggregation of services
Trials in Helsinki (Q3/04), Berlin (Q4/04), commercial limited opening in 2006 (Finland)
Operation scenario 1, 2 or 3
Mobile Broadcasting will happen : Mobile Broadcasting will happen Mobile broadcasting is becoming a fact in different parts of the world using terrestrial or satellite infrastructure
Satellite: MBSAT for Japan and Korea (just launched), US with XM Radio
Terrestrial: T-DAB and DVB-T deployed/selected in significant parts of the world with mobility as target for home and vehicular usage(?). DVB-H/T-DMB initiative are natural complement for handsets.
3G Cellular: Reserved for unicast, potentially multicast with limited throughput but no real broadcast services could be offered
Broadcast services on Handset will be a mix of Live TV and on demand video
Open service platform is key in the success of those services, with a seamless delivery between broadcast and unicast/multicast services
Mobile Operators have to assess cooperation/competition issues between broadcast technologies and mobile network
Clear role distribution between Broadcaster and Mobile operators is key in the success of Mobile broadcast services
The convergence challenge : The convergence challenge Mobile operator and content editors/Broadcaster to find agreement on a long list of issues
Resources sharing
Access to customer
billing policy
Sharing revenues
Subsidizing of bi-mode terminal
Portal content policy
Service exclusivity
Mobile right issues
Infrastructure deployment and O&M, ...
Political/regulatory issues to shape the agreement framework
Several Mode of Operation can be envisaged
The SDMB architecture: a satellite overlay network for 3G and beyond 3G network : The SDMB architecture: a satellite overlay network for 3G and beyond 3G network 3G Mobile Network 3G Base
station Content providers Hub based
on 3G equipment Content
Network High power
Geo-stationary satellite 3G handset Interactive link in IMT2000 mobile terrestrial band MBMS Broadcast/Multicast Service Centre Example of umbrella cells coverage
over Europe Satellite distribution link in IMT2000 mobile satellite band 3G Air interface
S-DMB: key design principles : 2G/3G HANDSET with extended frequency agility in Satellite IMT2000 band 512 Mbytes
Memory card
with integrated DRM Terrestrial repeaters integrated in 3G base stations for dense urban area coverage STORE REPLAY PUSH SELECT S-DMB: key design principles Satellite IMT2000 FDD European allocation Terrestrial IMT2000 FDD European allocation Terrestrial IMT2000 TDD European allocation 1900 1980 2010 2170 2200 MHz 1920 2110 2025 Hybrid satellite/terrestrial architecture: Global coverage for Outdoor & Indoor usage
Low cost impact on 3G handheld terminal
Satellite frequencies are adjacent to IMT2000 terrestrial ones
Satellite waveform compliant to 3GPP UTRA FDD WCDMA standard
High reception margin, hence no form factor impact
Concurrent evolution with 3GPP architecture Return link: PPDR, safety
High power GEO satellite to accommodate 3G handheld terminal RF characteristics : High power GEO satellite to accommodate 3G handheld terminal RF characteristics Satellite & Payload characteristics
15 years Lifetime
Launch mass: up to 5900 Kg
P/L DC power consumption: 12 kW
Up to 6 beams per satellite
EIRP (EOC): up to 76 dBW/beam over 1° Example of 1° Beams Satellite flexibility
Coverage (beam selection and beam size)
Power sharing among active beams
Transparent architecture towards 3GPP air interface (e.g. W-CDMA & Beyond 3G waveform)
Terrestrial repeater : Terrestrial repeater Rx antenna dish
20-30 cm
Ka band RF filter Power
Amplifier * RF cable to Node B antenna
(Signal is 3GPP TS 25.106 compliant
in IMT2000 satellite band) Low Noise Block CellularModem Frequency conversion terrestrial repeater
Block architecture O&M controller Typical installation in tri-sectorised site Site sharing with
2G/3G base station site
* cost effective
* environment friendly:
- Antenna sharing with
NodeB possible.
- RF power ~ 10 W
S-DMB enabling features in 3G user equipment : S-DMB enabling features in 3G user equipment 3GPP & OMA features
HW: Local memory storage
SW
MBMS (including Power saving management)
Streaming service and related codecs
Digital Right Management
Mobile broadcast services (service discovery, service protection, electronic service guide, etc...)
SDMB specific
HW: Radio frequency agility extension to IMT2000 satellite band
SW
Reliable transport protocol (File FEC, Interleaving, Carrousel)
Dual operation mode: SDMB reception while attached to UMTS or GSM network
SDMB Service management
Conclusion : Conclusion S-DMB is designed as an open infrastructure providing efficient content delivery services to 3G mobile operators, to meet the Mobile Video challenge
Viable positioning compared to DVB-H in the following situations:
Coverage at low cost focusing on Mobile video business model rather than TV
Regulations or competitive environment blocking the Broadcasters/Mobile operators co-operation
Technological competition between DVB-H and UMTS
MAESTRO is the cornerstone to demonstrate the SDMB value proposition toward mobile industry
Need to implement appropriate regulatory framework for 3G satellite systems in Europe
Paving the way for appropriate regulation in other part of the world