Satellite Communications A - University of Surrey

Satellite Communications A - University of Surrey

EEM.scmB Satellite Communications B Spring Semester 2004-5 -Satellite Broadcasting-Professor Barry G Evans- Spring2005 University of Surrey SatComms B - General - B G Evans 1 Contents 1. Analogue TV Satellite Broadcasting 2. Digital Satellite Broadcasting (MPEG/DVB-S) 3. New DVB-S2 standard and IP Delivery 4. DMB Spring2005 University of Surrey SatComms B - General - B G Evans 2 1. Analogue Satellite Broadcasting F.M. Theory S/NW versus C/N DTH/Cable head systems

WARC Broadcasting Plan MAC Systems Spring2005 University of Surrey SatComms B - General - B G Evans 3 System model Spring2005 University of Surrey SatComms B - General - B G Evans 4 FDM/FM techniques Spring2005 University of Surrey SatComms B - General - B G Evans 5 FM Transmission Formats NB. FDM/FM being replaced . Digital IDR TDM/PSK/FDMA Spring2005 University of Surrey SatComms B - General - B G Evans

6 Characteristics of Frequency Modulation (FM) Spring2005 University of Surrey SatComms B - General - B G Evans 7 FM Threshold Effect TRADE OFF BETWEEN POWER AND BANDWIDTH F.M.EQN: S C 1 3 2 mo N NO fm 2 where Spring2005 University of Surrey mo f fm SatComms B - General - B G Evans

8 FM Theory 2 Signal kf General fU Noise N o f 2 df fL f 3 3 fU fL 2 S 3 f

C 3 N f U f L3 N o or 2 S 3 B f C 3 N f U f L3 N o note f is the rms deviation. fm peak deviation fPK 2 S 3Br f PK C N f U3 f L3 N o

r = pk-rms ration note that then S is the signal pk Spring2005 University of Surrey SatComms B - General - B G Evans 9 Quality objectives for television (CCIR Rec. 567-1 & 568) Spring2005 University of Surrey SatComms B - General - B G Evans 10 ITU-R Subjective Quality Service Picture Quality 5 (excellent) 4 (good) 3 (fair) 2 (poor) 1 (bad) Spring2005 University of Surrey Weighted S/N(dB) 46.6 99.9% ITU-R 42.3

VIDEO REC. QoS 38.0 33.6 29.3 SatComms B - General - B G Evans 11 Base band signals television Spring2005 University of Surrey SatComms B - General - B G Evans 12 FM Theory Television BASEBAND SIGNAL (FDM) = 6MHZ SIGNAL 1V pk-pk Test signal F.M. EQUATION, 2 S C 3B f N N f U3 f L3 For T.V. fL << fU

fL=0, fU=fm f = Fr (rms deviation of signal) S C 3BFr N N f m3 2 CCIR Definition S/No - pk-pk video voltage = S Fpp should be used Test-Tone for T.V. includes Synch tip. 0.7 x pk-pk volts = pk-pk video FTT2 2 2 FPP 0.7 FTT 2 S C 3B FTT * * N N 2 f m3 Spring2005 University of Surrey 2

SatComms B - General - B G Evans 13 Analogue transmission techniques -SCPC/FM transmission of television- Spring2005 University of Surrey SatComms B - General - B G Evans 14 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. Spring2005 University of Surrey SatComms B - General - B G Evans 15 Communication techniques

Spring2005 University of Surrey SatComms B - General - B G Evans 16 FM Theory Television 15 KHz TEST-TONE APROACH For A 1v pk-pk Test Signal with fixed pattern Alternate BlackWhite lines, which is convenient Test Signal equivalent deviation 15KHz sinusoid T.T. FTPP 2 S 3B C FTPP WP N 2 N f m3 (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 calcs the noise is calculated Is a top baseband of fm=5MHz. Then : 625 Line (WP) = 13.2 dB. 525 Line (WP) = 14.8 dB Spring2005 University of Surrey SatComms B - General - B G Evans

17 Video Weighting Factor 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. Frequency characteristics of weighting networks for measuring continuous random noise * Improvement by emphasis + weighting factor. (P+O) Spring2005 University of Surrey SatComms B - General - B G Evans 18 TV via Satellite Example INTELSAT : 625/50 Hz ASTRA DTH. FTPP = 15 MHz. fm= 6MHz fm = 5MHz S 3 FTPP N 2 fm

2 1 fm pw S N C N0 2 3 15 1 C .( pw). 2 5 5 N0 C 42.5dB N0 2

3 13.5 1 C .( pw). 2 5 5 N0 C 43.4 N0 DTM. S/N=42.3, C/No = 89.8 dB-H Bw = 13.5 + 2x6 = 25.5 MHz C/N 15 dB Allows Rain fade to threshold Aim for Fixed Link. S/N=45 dB. C/No=87.5 dB-MHz BW = 15 + 2x6 = 27 MHz Also TPDR. TV. 15.75 MHz BW. 2 x TV in 36MHz S/N = 29.5 + C/N = 45 C/N = 15.5 dB Spring2005 University of Surrey SatComms B - General - B G Evans 19 Satellite TV Over Deviation Use BW narrower than Carson without excessive distortion BC 2 FFP fm

625/50 TV FM occupy BW 18MHz 18 FFP 6 3MHz 2 INTELSAT actually use PK devn 10.5MHz Carson Called ' over deviation' 20log actual 20log 10.5 10.9dB Carson 3 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 Spring2005 University of Surrey SatComms B - General - B G Evans 20 Spring2005 University of Surrey SatComms B - General - B G Evans

21 Data sub-carrier 2 C C f sc 10 log 1 2 f sc N 0 dsc N 0 mc Eb C 2 N 0 data N 0 dsc Rb S

N mc 2 f p p 1 C 2 Q 3r f m f m N 0 mc r ratio pk - pk amp. of monochrome video to nominal amp. luminance f p p pk - pk deviation produced by sinusoidal signal at 15kHz f m top baseband of video (5 MHz) Q pre emphasis weighting advantage (13.2 dB) Spring2005 University of Surrey SatComms B - General - B G Evans 22 TVRO Satellite TV Transponder = +52 dBW Dish size TVRO = 60 cm LNB = 1.5 dB noise fig (120K) Transmit eirp Pointing loss Clear sky abs. Loss F.S.L (14.5 GHz) Satellite G/T (Land)

K +80 dBW 0.2 dB 0.5 dB 207.3 dB +7 dB/K -228.6 dBW/Hz/K UPLINK: DOWNLINK : OVERALL C/N0 107.6 dB-Hz Transponder eirp (saturation) F.S.L (12 GHz) Clear Sky absorption (12 GHz) TVRO ptg.loss TVRO G/T (elev. Sky) K C/N0D 52 dBW 205.5 dB 0.4 dB 0.3 dB

12 dB/K -228.6 dBW/Hz/K 86.4 dB-Hz C / (N0D+N0U) C / N(in 26 MHz) C / I(adj. Satellites + X path) C / (NTH + Nint) Deviation (FTPP) W+P S/N 86.4 dB-Hz 12.2 dB 28.0 dB 12.1 dB 16 MHz 13.2 dB 44.2 dB NB 2 dB better than CCIR-4 (Good) At C/N THRESHOLD = 0 dB gives 3.1 dB margin for propagation Spring2005 University of Surrey SatComms B - General - B G Evans 23

Link Performance -Exercise SATELLITE eirp=+40dBW TV FREE SPACE LOSS 250.6DB Diameter? =65% T=22.3dB-K RX DMD S/N=42.3dB 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. Spring2005 University of Surrey SatComms B - General - B G Evans 24 TV TRANSMISSION ASTRA eirp = +52dBW 11.5GHz 14.5G Hz C/I=28dB G/T=+7dB/k 205.5dB 207.3dB eirp

+80dBW TELEPOR T =0.6 ATV link to TVRO from Astra TVRO LNB 1.5dB noise Fig. 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. Spring2005 University of Surrey SatComms B - General - B G Evans 25 Model of a Broadcasting Satellite System

Spring2005 University of Surrey SatComms B - General - B G Evans 26 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 Spring2005 University of Surrey SatComms B - General - B G Evans 27

BSS Planning in Europe (1/3) Spring2005 University of Surrey SatComms B - General - B G Evans 28 BSS Planning in Europe (2/3) Spring2005 University of Surrey SatComms B - General - B G Evans 29 BSS Planning in Europe (3/3) Spring2005 University of Surrey SatComms B - General - B G Evans 30 ITU Region 1 Ku Band Frequency Plan Spring2005 University of Surrey SatComms B - General - B G Evans 31

The MAC/Packet innovation Time division multiplex components Spring2005 University of Surrey SatComms B - General - B G Evans 32 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 TIME COMPRESSION Luminance TIME COMPRESSION Sound+data TIME COMPRESSION

Spring2005 University of Surrey TDM SatComms B - General - B G Evans MOD RF MOD 33 MAC format options C-MAC Time Division Multiplex (TDM) at radiofrequency of time compressed TV signal analogue components and digital components (sound/data) Chrominance TIME COMPRESSION TDM Luminance TIME COMPRESSION MOD RF

TDM Sound+data Spring2005 University of Surrey TIME COMPRESSION SatComms B - General - B G Evans MOD 34 2. Digital Broadcasting MPEG Compression Techniques MPEG Packets DVB-S Transmission Spring2005 University of Surrey SatComms B - General - B G Evans 35 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 Spring2005 University of Surrey SatComms B - General - B G Evans 36 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 2736MHz bandwidth, cost roughly 2-3m/year, and can carry 30-40Mbit/s OR one FM TV channel. Transponder cost/channel is much lower for MPEG2 compression than FM-TV. Digital format allows many more applications. Spring2005 University of Surrey SatComms B - General - B G Evans 37 Elements of a digital satellite broadcasting system STUDIO Camera MPEG-2 Encoder

Tape Multiplexer Film File server Contribution Modulator MPEG-2 Encoder Electronic Programme Guide (EPG) Subscriber Management System Spring2005 University of Surrey Conditional Access System SatComms B - General - B G Evans 38 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) Spring2005 University of Surrey SatComms B - General - B G Evans 39 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. Spring2005 University of Surrey SatComms B - General - B G Evans 40 Temporal redundancy Predicted frames Intraframes Use motion estimation to predict the next frame. Use DCT to encode the difference between predicted and actual. Spring2005 University of Surrey SatComms B - General - B G Evans

41 Spatial redundancy Operates on blocks of 8x8 pixels. Discrete Cosine Transform (DCT) converts spatial elements to frequency domain (lossless). Scaling related to human visions perceptual sensitivity. Quantisation controlled by feedback from rate buffer. Spring2005 University of Surrey SatComms B - General - B G Evans 42 Spatial redundancy 176 176 176 176 176 176 176

176 171 171 171 171 171 171 171 171 185 185 185 185 185 185 185 185

203 203 203 203 203 203 203 203 206 206 206 206 206 206 206 206

203 203 203 203 203 203 203 203 193 193 193 193 193 193 193 193 178

178 178 178 178 178 178 178 Pixel values for a block taken from a typical picture Increasing horizontal frequency Increasing vertical frequency Values after DCT processing Spring2005 University of Surrey 1106 12

-22 12 4 6 2 0 145 -15 -16 10 3 7 1 0 98 -4 -20

4 5 1 1 -1 52 -15 -8 1 -1 2 -2 0 18 -10 -1

-1 -1 1 -2 0 9 -4 -3 -2 1 -1 0 0 -4 2 -4 1

-3 2 1 0 -13 1 0 0 -1 1 1 2 SatComms B - General - B G Evans 43 Spatial redundancy DCT values after quantisation and scaling: Increasing horizontal frequency

Increasing vertical frequency Spring2005 University of Surrey 138 1 -1 0 0 0 0 0 8 -1 -1 0 0 0

0 0 5 0 0 0 0 0 0 0 2 -1 0 0 0 0

0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 SatComms B - General - B G Evans 44 Spatial redundancy Conversion to serial data by zig-zag scanning: 138 1 -1 0 0 0 0 0 8 -1 -1 0 0

0 0 0 5 0 0 0 0 0 0 0 2 -1 0 0 0

0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 Run length coding removes long strings of zeros. Variable length coding replaces common values with shorter symbols (c.f. Morse code). Spring2005 University of Surrey SatComms B - General - B G Evans 45 Control of quantisation Quantisation threshold From DCT process Quantisation of DCT coefficients Data rate control Variable length coding Buffer occupancy Buffer

store Variable rate Spring2005 University of Surrey SatComms B - General - B G Evans Fixed rate 46 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. Spring2005 University of Surrey SatComms B - General - B G Evans 47 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. Spring2005 University of Surrey SatComms B - General - B G Evans 48 MPEG system layer Elementary Programme streams streams Video encoder Transport stream Audio encoder Data encoder Other programmes Other data Spring2005 University of Surrey SatComms B - General - B G Evans

49 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. Spring2005 University of Surrey SatComms B - General - B G Evans 50 Channel adaptation Channel Adaptation: the processes involved in taking a Transport Stream and converting it to a form suitable for transmission on the satellite. Transport stream Energy dispersal Outer FEC encoder Inner FEC encoder

Spring2005 University of Surrey Interleaver Baseband shaping SatComms B - General - B G Evans QPSK Modulation To RF channel 51 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. Spring2005 University of Surrey SatComms B - General - B G Evans 52 Outer FEC encoding Reed-Solomon (204,188) encoding adds 16 bytes to each MPEG packet. 204 bytes

204 bytes 188 bytes 188 bytes 16 bytes RS Spring2005 University of Surrey SatComms B - General - B G Evans 16 bytes RS 53 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. Spring2005 University of Surrey SatComms B - General - B G Evans 54 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. Spring2005 University of Surrey SatComms B - General - B G Evans 55 Modem performance DVB specifies modem performance in IF loop to achieve quasi error-free performance: Inner code rate 1/2 2/3 3/4 5/6 7/8 Eb/No (dB) 4.5 5.0 5.5 6.0 6.4 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. Spring2005 University of Surrey SatComms B - General - B G Evans

56 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. Spring2005 University of Surrey SatComms B - General - B G Evans 57 Modulation BPSK has largest inter-symbol distance. QPSK has half BPSKs symbol rate, so half the bandwidth. Inter-symbol distance is down 3dB relative to BPSK, but so is received noise power! Q Q 0 1,0 I

I 1 1,1 BPSK constellation Spring2005 University of Surrey 0,0 0,1 QPSK constellation SatComms B - General - B G Evans 58 Baseband shaping Amplitude Slow roll-off Spring2005 University of Surrey Nyquist bandwidth Medium roll-off SatComms B - General - B G Evans

Fast roll-off 59 Modulation performance Typical receiver performance in a linear channel: Note: in this case the bit rate used to calculate Eb/N0 from C/N0 is the channel rate. Measured Theoretical Spring2005 University of Surrey SatComms B - General - B G Evans 60 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. Spring2005 University of Surrey

SatComms B - General - B G Evans 61 Effect of TWTA on spectrum Spectrum of 11Mbits/s (gross rate) QPSK signal after passing through a wideband TWTA at saturation. Spring2005 University of Surrey SatComms B - General - B G Evans 62 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.

Spring2005 University of Surrey SatComms B - General - B G Evans 63 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. 46.8Mbits/s From demodulator 35.1Mbits/s Convolutional decoding (3/4) (Inner code) Spring2005 University of Surrey 32.3Mbits/s RS (204,188) decoding MPEG stream to decoder (Outer code)

SatComms B - General - B G Evans 64 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. FM Picture Quality Digital FM threshold Digital threshold C/N Spring2005 University of Surrey SatComms B - General - B G Evans 65 Picture impairments Impairments are different from PAL (eg crosscolour). 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. Spring2005 University of Surrey SatComms B - General - B G Evans 66 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 Spring2005 University of Surrey SatComms B - General - B G Evans 67 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-SRCS. These topics will be covered in an associated

lecture (Dr Haitham Cruickshank) Spring2005 University of Surrey SatComms B - General - B G Evans 68 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/Ns Spring2005 University of Surrey SatComms B - General - B G Evans 69 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 Spring2005 University of Surrey

SatComms B - General - B G Evans 70 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, , 3/5, 2/3, , 4/5, 5/6, 8/9, 9/10 Concatenated scheme Inner LDPC Outer BCH Spring2005 University of Surrey SatComms B - General - B G Evans 71 Modulation schemes DVB-S2 Q I=MSB 10 100 110

00 Q Q=LSB 000 I I 010 001 11 011 01 101 111 Q 01101

11101 1010 1000 LSB R1 1100 11001 00101 R3 MSB 0000 R2 1110 01001 01100 0010 0110

Q 0100 11100 11110 00100 10100 00001 00000 R2 10101 R1 01000 10000 10001 11000 I text 0111

1111 I text 1101 10110 0101 10111 10010 10011 01110 00010 00110 0011 11010 0001 00111 11111

1011 1001 01111 00011 01011 01010 11011 The four possible DVB-S2 constellations before physical layer scrambling Spring2005 University of Surrey SatComms B - General - B G Evans 72 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 nonlinear. Schemes better in non-linear channel cf. 16/32 QAM Roll-off factors - =0.35, 0.25, 0.2 Spring2005 University of Surrey

SatComms B - General - B G Evans 73 Modulation schemes DVB-S2 Single Input Stream DATA ACM COMMAND Input interface & adaptation tools #1 Merger Slicer Input interface & CRC-8 adaptation Encodertools #n Multiple Input Streams 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9, 9/10 BB Signalling

STREAM ADAPTER BCH outer LDPC inner PL Signalling Pilot symbols QPSK, 8PSK, 16APSK, 32APSK constellations MODE & STREAM FEC ENCODING MAPPING ADAPTATION BBFRAME LP stream for BC modes SCRAM BLER =0,35, 0,25, 0,20 BB Filter & Quadrature Modulation

Dummy FRAME PL FRAMING MODULATION PLFRAME to the RF satellite channel Functional block diagram of the DVB-S2 system Spring2005 University of Surrey SatComms B - General - B G Evans 74 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 Spring2005 University of Surrey

SatComms B - General - B G Evans 75 Framing Structure: the system train FEC redundancy Useful data Type of channel coding and modulation adopted in the wagon PL FRAME H FEC FRAME 8PSK 5/6 H FEC FRAME QPSK 2/3 H FEC FRAME 16APSK 3/4

Pictorial representation of the physical layer framing structure Spring2005 University of Surrey SatComms B - General - B G Evans 76 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 Spring2005 University of Surrey SatComms B - General - B G Evans 77 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) Spring2005 University of Surrey SatComms B - General - B G Evans 78 DVB-S2 Performance Spectrum efficiency versus required C/N on AWGN channel 4,5 32APSK Ru [bit/s] per unit Symbol Rate 4,0 Dotted lines= modulation constrained Shannon limit 16APSK 3,5 3,0 2,5 8PSK DVB-DSNG 2,0 QPSK

1,5 DVB-S 1,0 0,5 0,0 -3 -2 -1 0 1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 C/N [dB] in Rs Required C/N versus spectrum efficiency, obtained by computer simulations on the AWGN channel (idea demodulation) (C/N refers to average power) Operates C/Ns 2.4dB with QPSK/1/4 to 16dB with 32APSK/9/10 (for PER of 107) Note: 20-35% capacity increase over DVB-S Spring2005 University of Surrey SatComms B - General - B G Evans 79 DVB-S2 Range of C and M Examples of useful bit rates Ru versus LDPC code rate per unit symbol rate

Rs Spring2005 University of Surrey SatComms B - General - B G Evans 80 Comparison DVB-S and S2 (CCM) Example comparison between DVB-S and DVB-S2 for TV broadcasting Satellite EIRP (dBW) 51 53.7 System DVB-S DVB-S2 DVB-S DVB-S2 Modulation & coding QPSK 2/3 QPSK 3/4 QPSK 7/8 8PSK 2/3 Symbol-rate (Mbaud) 27.5 (=0.35) 30.9 (=0.20) 27.5 (=0.35) 29.7 (=0.25) C/N (in 27.5 MHz) (dB) 5.1 5.1 7.8 7.8 Useful bit-rate (Mbit/s) 33.8 46 (gain=36%) 44.4

58.8 (gain=32%) Number of SDTV 7 MPEG-2 10 MPEG-2 10 MPEG-2 13 MPEG-2 programmes 15 AVC 21 AVC 20 AVC 26 AVC Spring2005 University of Surrey SatComms B - General - B G Evans 81 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 Spring2005 University of Surrey SatComms B - General - B G Evans

82 Using ACM for IP Unicast (1) UP-LINK STATION ACM DVB-S2 MODULATOR ACM command: Modulation & coding selection High bit-rate forward-link ACM Gateway C/N+I signalling Info SOURCE(s) User bit-rate control Return channel Satellite Terminal C/N+I measurement 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. Spring2005 University of Surrey SatComms B - General - B G Evans 83 Using ACM for IP Unicast (2) ACM DVB-S2 SYSTEM BUF Info Response Info Provider BUF ACM Command BUF High bit-rate forward-link Info Response C/N+I signalling

Info Response Internet ACM routing manager Buffers per: Protection level user service level level M1 ACM Router ACM Satellite Gateway Router Interaction channel GW Server Return channel Satellite

Terminal Info Request Example of IP services using a DVB-S2 ACM link Spring2005 University of Surrey SatComms B - General - B G Evans 84 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. Spring2005 University of Surrey SatComms B - General - B G Evans 85 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 Spring2005 University of Surrey SatComms B - General - B G Evans 86 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). Spring2005 University of Surrey SatComms B - General - B G Evans 87 DMB: convergence of different worlds BROADCASTING

Webaccess Driven DMB Gamin g Driven PC WORLD INTERNET Live TV Driven Tecnholog y Driven MOBILE TELECOMs Spring2005 University of Surrey SatComms B - General - B G Evans 88 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 Spring2005 University of Surrey SatComms B - General - B G Evans 89 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. Spring2005 University of Surrey SatComms B - General - B G Evans 90 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) Spring2005 University of Surrey SatComms B - General - B G Evans 91 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) Spring2005 University of Surrey SatComms B - General - B G Evans 92

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 Spring2005 University of Surrey SatComms B - General - B G Evans 93 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 Spring2005 University of Surrey SatComms B - General - B G Evans 94 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 Remote Constellation: Uplink Site 3 HEO sat Terrestrial repeaters (~ 90) TDM TDM Ground Repeaters OFDM TDM Mobile

Receiver OFDM TDM 12.5 MHz National Broadcast Studio Air interface: VSAT Satellite SIRIUS Satellite Direct link: QPSK TDM Terrestrial repeater link: QPSK COFDM Coding: RS+Conv Sat diversity Spring2005 University of Surrey SatComms B - General - B G Evans 95 MBSAT

MBSAT (Japan and Korea) System Cost ~800 M$ 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 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 Spring2005 University of Surrey SatComms B - General - B G Evans 96 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 Spring2005 University of Surrey SatComms B - General - B G Evans 97 DVB-H System overview (1) Objectives Constraints Broadcast transmission to mobile handheld terminals of datagrams (IP or other datagrams)

pertaining to multimedia services, file downloading services, etc 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 Spring2005 University of Surrey SatComms B - General - B G Evans 98 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 Spring2005 University of Surrey SatComms B - General - B G Evans 99 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 Spring2005 University of Surrey SatComms B - General - B G Evans 100

DVB-T/H: functional block diagram Spring2005 University of Surrey SatComms B - General - B G Evans 101 DVB-T/H: MPEG-2 MPEG-2 MPEG-2transport transportmultiplex multiplexpacket: packet: 188 188byte: byte:11synch synchword word++payload payload Sync 1 byte Spring2005 University of Surrey MPEG-2 transport MUX data 187 bytes SatComms B - General - B G Evans 102

DVB-T/H: RS outer coding RS RS(204, (204,188, 188,t=8) t=8) Spring2005 University of Surrey SatComms B - General - B G Evans 103 DVB-T/H: outer interleaving Convolutional interleaving (Forney approach) INTERLEAVING DEPTH = 12 BYTES Spring2005 University of Surrey SatComms B - General - B G Evans 104 DVB-T/H: inner convolutional coding Convolutional Convolutionalcodes: codes:

Mother Mothercode coderate rate1/2, 1/2,64 64states states 171oct, G2=133oct G G1= 1= 171oct, G2=133oct Punctured Puncturedcodes codesatatrates rates 2/3 2/3 3/4 3/4 5/6 5/6 7/8 7/8 This Thisisisthe thesame samecode codeused usedby byDVB-S DVB-S Spring2005 University of Surrey

SatComms B - General - B G Evans 105 Mobile TV: the DVB-T/H technology MPEG-2 over IP over DVB-T DVB-H 24 Mbps Source Nokia 2003 128-400 3 Mbps 4-6 TV programs for large screen > 5 to 10 Mbps kbps 50-80 video streams for small screen

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 SatComms B - General - B G Evans 106 Spring2005 University of Surrey 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 Spring2005 University of Surrey SatComms B - General - B G Evans 107 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 Spring2005 University of Surrey SatComms B - General - B G Evans 108 The SDMB architecture: a satellite overlay network for 3G and beyond 3G network High power Geo-stationary satellite 3G handset Example of umbrella cells coverage over Europe Satellite distribution link in IMT2000 mobile satellite band 3G Air interface Interactive link in IMT2000 mobile

terrestrial band 3G Base station Spring2005 University of Surrey 3G Mobile Network Hub based on 3G equipment Content Network Content provide rs MBMS Broadcast/Multicast Service Centre SatComms B - General - B G Evans 109 S-DMB: key design principles 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 19001920 1980 20102025 Return link: PPDR, safety 2110 21702200 MHz Satellite IMT2000 FDD European allocation Terrestrial IMT2000 FDD European allocation Terrestrial IMT2000 TDD European allocation 2G/3G HANDSET with extended frequency agility in Satellite IMT2000 band Spring2005 University of Surrey

PUSH Terrestrial repeaters integrated in 3G base stations for dense urban area coverage SELEC T STORE REPL AY SatComms B - General - B G Evans 512 Mbytes Memory card with integrated DRM 110 High power GEO satellite to accommodate 3G handheld terminal RF characteristics Ka band RX Antenna < 1.2 m IMT2000 Satellite band TX/RX Antenna 12 m Ka band

TX Antenna < 1.5 m Mirror or subreflector Example of 1 Beams Satellite & Payload characteristics Satellite flexibility 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 Spring2005 University of Surrey Coverage (beam selection and beam size) Power sharing among active beams Transparent architecture towards 3GPP air interface (e.g. W-CDMA & Beyond 3G waveform) SatComms B - General - B G Evans 111

Terrestrial repeater Low Noise Block Rx antenna dish 20-30 cm Ka band Power Amplifier RF filter O&M controlle r * RF cable to Node B antenna (Signal is 3GPP TS 25.106 compliant in IMT2000 satellite band) Cellula rMode m Frequency conversion terrestrial repeater Block architecture Site sharing with

2G/3G base station site * cost effective * environment friendly: Rx Antenna Tx antenna Repeater Tx antenna On the rooftop - Antenna sharing with NodeB possible. - RF power ~ 10 W Typical installation in tri-sectorised site Spring2005 University of Surrey SatComms B - General - B G Evans 112 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 19001920 1980 20102025 2110 21702200 MHz Reliable transport protocol (File FEC, Interleaving, Carrousel) Dual operation mode: SDMB reception while attached to UMTS or GSM network SDMB Service management Spring2005 University of Surrey SatComms B - General - B G Evans 113 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 Spring2005 University of Surrey SatComms B - General - B G Evans 114

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