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工業技術研究院Industrial Technology Research Institute
DVBDVB--C2 technology overviewC2 technology overview
工業技術研究院資通所
侯信安
[email protected]年5月18日
Copyright © ITRI 工業技術研究院2
AgendaAgendaq Introduce to second generation DVB broadcast
standardsv History & evolution v New features in second generation DVB broadcast standards
q DVB-T2 technology overview v Commercial requirement v Key features to physical layerv Stream distribution method & Aid for network optimization v Possible applied scenarios v Comparison and conclusions
q DVB-C2 technology overviewv Commercial requirement v Key features to physical layerv Impact on current systemv Possible applied scenarios v Comparison and conclusions
Copyright © ITRI 工業技術研究院3
analogue remains while digital explodesanalogue remains while digital explodes
Source: Bart Brusse, “The DVB Project and DVB-C2 - An Introduction,” DVB-C2 Face-2-Face meeting, Denver, CO, 10 February 2010
Copyright © ITRI 工業技術研究院4
mid term capacity shortages in many mid term capacity shortages in many marketsmarkets
Source: Bart Brusse, “The DVB Project and DVB-C2 - An Introduction,” DVB-C2 Face-2-Face meeting, Denver, CO, 10 February 2010
Copyright © ITRI 工業技術研究院5
Commercial RequirementsCommercial Requirementsq Expected capacity shortage among several large
operators in 2011-2013 timeframeq DVB-CM-C2 process started September 2007v Definition of use cases for a new specificationv Extracting commercial requirements for specification
q Commercial requirements released early 2008v Optimize use of cable channels & use existing technologyv Increase capacity (min. 30%) & allow global implementation
modulation & FEC schemesv No backwards compatibility requirements, but no requirement for
changes in network architecture or channel characteristicsv Possibility to implement the new technology into EuroDOCSIS
Copyright © ITRI 工業技術研究院6
DVBDVB--C2 Overall Schedules and MilestonesC2 Overall Schedules and Milestones
DVB-TM
DVB-CM
DVB-TM
Industry
CfT Specification
Call for Techno-logies
ChannelModel
Approval
CommercialRequirements
StudyMission
Approval
Approval
ImplementationGuidelines
ETSIPublic Enquiry
Chip Design
ETSI
Industry
Q1 Q2 Q4
2008
Q3Q4
2007
Q3Q2Q1 Q1 Q2 Q4
2009
Q3
2010
Q1
CPE DesignIndustry
Copyright © ITRI 工業技術研究院7
DVBDVB--C2 documentsC2 documents
Copyright © ITRI 工業技術研究院8
C2 Frame structureC2 Frame structure
Copyright © ITRI 工業技術研究院9
C2 SystemC2 System
q Input pre-processor v Split TS/GS to PLPsv Extract common PLP from
TS/GS
q Input processing v Mode adaption v Stream adaption
Bit
Interleaved Coding &
Modulation
Data Slice + Frame Builder
OFDM
generation
TS or GSE inputs
Input
processing
C2 system DVB-C2 output
Copyright © ITRI 工業技術研究院10
C2 Frame structure for 6/8 MHz C2 Frame structure for 6/8 MHz
Copyright © ITRI 工業技術研究院11
Improving spectrum efficiencyImproving spectrum efficiency
DVB-CSingle carrier
DVB-C2Multiple Carrier
Loss due to guard band
Loss due to shaping filter
8 MHz
e.g.24 MHz
Φ(f)
Φ(f)
DVB-CSingle carrier
DVB-C2Multiple
Carrier
8 MHz
e.g.24 MHz
Φ(f)
Φ(f)
Interference:Narrow band: public service channelsBroadband: LTE (790-862)
Loss all 8 MHz BW
Loss interference BW only
Description Parameter Overhead
Single carrier Shaping filter
Roll-off factor. 0.15 for DVB-C
15 %
Guard interval 1/128 Preamble 1 symbol Pilot density 1/96
Multiple carrier (OFDM)1
Guard band 200 KHz
3.25 (+0.22) %
1 32 MHz bandwidth, e.g. 5 data slices of 6.4 MHz
Narrow Notch 25 KHz (current aircraft radio ) Overhead1
Single carrier
Forbid the whole occupied 8 MHz spectrum
25 %
Multiple carrier (OFDM)
Forbid only occupied spectr um 11 carrier s
≅1 %
1 32 MHz bandwidth, e.g. 5 data slices of 6.4 MHz
Copyright © ITRI 工業技術研究院12
Notch in C2 FramesNotch in C2 Frames
time
time
Boar
d Ba
nd F
requ
ency
Not
ch
Narrowband notches
Broadband notches
Definition BW≤ 105 KHz BW> 105 KHz 1/64GI 11/ 23/ 35/ 47
carriers 11 carrier2 Bandwidth
1/128GI 23/47 carriers 23 carriers2 Notch position within a Data Slice
Yes No
Signaled in L1 Yes Yes Receiver handling Notch corrected
by L1 FEC Notch not inside tuning bandwidth
1 47 carriers at 8 MHz channel 2 minimum bandwidth no maximum, but one preamble adjacent to a Broadband notch
Copyright © ITRI 工業技術研究院13
Tuner windowTuner window
q Preamble is mapped depending the center of the tuner window
q The tuner window does not contain any broadband notch to make the decoding of L1 part signaling successful
Data Slice 1
Data Slice 2
Data Slice 3
Data Slice 4
Data Slice 5
Data Slice 6
448
OFD
M S
ymbo
ls
Data Slice 1
Data Slice 2
Data Slice 3
Data Slice 4
Data Slice 5
Data Slice 6
448
OFD
M S
ymbo
ls Broadband N
otch
Copyright © ITRI 工業技術研究院14
Absolute OFDMAbsolute OFDM
q The first L1 part 2 signalling block begins at the absolute frequency of 0 MHz
q Further blocks are partitioned in steps of 7.61MHz towards higher frequencies
q The pilot sequences of the OFDM signal are different for all different frequencies
q To avoid unwanted repetitions in the frequency domain which may cause unwanted high peak values of the OFDM signal in time domain
L1 Block L1 Block L1 Block L1 Block L1 Block L1 Block L1 Block
0 MHz
Frequency [MHz]
7.61 MHz
Actual DVB-C2 Signal
… …
Not Transmitted (virtual) L1 Data L1 Block
L1 Block Transmitted L1 Data
Copyright © ITRI 工業技術研究院15
PLP bundlingPLP bundling
q If the data rate of a broadband PLP exceeds the capacity of a single Data Slice, it can be spread across different Data Slices
q A single PLP can therefore allocate arbitrary bandwidths up to the whole C2 system bandwidth
q Data Slice decoding on receiver side can be realized by v Multiple standard tuners (e.g. 8 MHz)v Broader tuner architectures
Copyright © ITRI 工業技術研究院16
PLP BundlingPLP Bundling
DVB-C2 channel
2 21 4
MasterHE
IP-Backbone
OFDMModu-lator
StreamAdap-tion.
Data SlicingTim+Freq-Interl.
L1Configuration
DVB-C2-Phy(CCM)
1024 QAMCR=9/10
1024 QAMCR=9/10
1024 QAMCR=9/10
HFC
Data SlicingTim+Freq-Interl.
Data SlicingTim+Freq-Interl.
L1 block
Buf-fer
Buf-fer
Buf-fer
200Mbit/sdata stream(Internet)
Application example for PLP bundling; transmission of a high data rate MPEG2 transport stream via several bundled Data Slices in a DVB-C2 channel
Copyright © ITRI 工業技術研究院17
Adaptive Coding and Modulation (ACM) Adaptive Coding and Modulation (ACM)
Low robustness, high efficiency(coding, modulation)
High robustness, low efficiency(coding, modulation)
100% high efficient Mod/Cod (CCM) (1024QAM, CR = 8/9)
100% robust Mod/Cod (CCM) (1024Q AM, CR = 3/4)
VCM/ACM with 50% robust Mod/Cod 50% high eff Mod/Cod
Data Rate (32 MHz C2 channel) 269.3 MBit/s 226.65Mbit/s 248 MBit/s
Copyright © ITRI 工業技術研究院18
MasterHeadend
IP-Backbone
OFDMModu-lator
L1 configurationDVB-C2-Modulator (using GSE)
Stream Adapt. 1024QAM, CR=3/4 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=3/4
Stream Adapt. 1024QAM, CR=3/4 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=3/4
Stream Adapt. 1024QAM, CR=3/4 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=8/9
Stream Adapt. 1024QAM, CR=8/9 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=8/9
Stream Adapt. 1024QAM, CR=8/9 Data Slicing, Time+Freq.- InterleavingStream Adapt. 1024QAM, CR=8/9
IPTV streams
For user outlets with CNR=29dB
For user outlets with CNR=32dB
ACM using Variable Coding and Modulation ACM using Variable Coding and Modulation (VCM) in the DVB(VCM) in the DVB--C2 Modulator C2 Modulator
Copyright © ITRI 工業技術研究院19
64 QAMDVB-C
256 QAMDVB-C
PALsystemlevel
-6dB
1024 QAMDVB-C2
-6dB
4096 QAMDVB-C2
noise and intermodulation floor
Backoff
-12dB0dB
16K QAMDVB-C2Rev. ?16%
(+13.2 Mbit/s)To 4096 QAM
6dB
64K QAMDVB-C2Rev. ? 33%
(+26.4 Mbit/s)To 4096 QAM
12dB
PALAM/VSB
AnalogueTV
Signal Level
q DVB-C allows lower signal levels, related to PAL system levelv Low contribution to the intermodulation interferencev With long amplifier cascades downstream capacity is limited to about 4
Gbit/s due to upcoming intermodulation noise q DVB-C2 will increase this capacity to 6 Gbit/s according to
calculationsv For enhanced HFC networks up to 8 GBit/s seem to be feasiblev Highest spectrum efficiency 16k-/64-QAM in enhanced HFC networks for
further use
DVBDVB--C2, System Load ConsiderationsC2, System Load Considerations
Copyright © ITRI 工業技術研究院20
OFDM parametersOFDM parametersParameter "6 MHz"
1/64 "6 MHz"
1/128 "8 MHz"
1/64 "8 MHz"
1/128 Number of OFDM carriers per L1 Block KL1 3 408 3 408 3 408 3 408
Bandwidth of L1 Signalling Block (see note) 5,71 MHz 5,71 MHz 7,61 MHz 7,61 MHz
Element Period T µs 7/48 7/48 7/64 7/64 Duration TU 4096T 4096T 4096T 4096T Duration TU µs (see note) 597,3 597,3 448 448 Carrier spacing 1/TU (Hz) (see note) 1 674 1 674 2 232 2 232 Guard Interval Duration ∆/Tu 64T 32T 64T 32T Guard Interval Duration ∆/Tu µs (see note) 9,33 4,66 7 3,5 Frame Duration TF ms (see note) 271.8 269.7 203.8 202.2 NOTE: Numerical values in italics are approximate values.
Ndata Symbols
Guard Interval
Ndata Duration (ms)
TI MODE Npreamble symbols
% preamble overhead
Nsymbols in Frame
Frame Duration (ms)
448 1/128 202.3 00, 01 1 (min.) 0.22 449 202.7 448 1/128 202.3 00, 01 7 (max.) 0.54 455 205.4 448 1/128 202.3 10 4 0.88 452 204.1 448 1/128 202.3 11 8 1.75 456 205.9 448 1/64 203.8 00, 01 1 (min.) 0.22 449 204.3 448 1/64 203.8 00, 01 7 (max.) 0.54 455 207.0 448 1/64 203.8 10 4 0.88 452 205.7 448 1/64 203.8 11 8 1.75 456 207.5
Frame duration in DVB-C2
Copyright © ITRI 工業技術研究院21
DVBDVB--C2 C2 v.sv.s. DVB. DVB--CCq DVB-C2 performance is close to the theoretical limitq Increased robustness:7 dBq Increase of spectral efficiency: 35 %q Gain of spectral efficiency in modern HFC networks: 60 %
DVB-C2 parameters: 32 MHz signal bandwidth, Guard Interval 1/128, pilot density 1/96
Copyright © ITRI 工業技術研究院22
Echo Echo
IEEE 802.14
Time delay (ns)
IEEE 802.14
Time delay (ns)
Length segment [m] 250 50 10 2
Frequency [MHz} 140 800 140 800 140 800 140 800
Reflection loss (2x) [dB] 36 20 36 20 36 20 36 20
Attenuation @ 3dB/100m (200MHz) [dB] 15 30 3 6 0,6 1,2 - -
Total Loss [dB] 51 50 39 26 37 21 36 20
Delay [ns] 2500 500 100 20
Copyright © ITRI 工業技術研究院23
q The intermodulation products can be distinguished in three types v Narrow band intermodulation products, the CSO and CTB cluster
beatsv Broadband, random noise-like intermodulation productsv Impulse noise
Nonlinear behaviour of components Nonlinear behaviour of components
CSO: Composite Second Order (2nd order component) CTB: Composite Triple Beat (3rd order component)
Copyright © ITRI 工業技術研究院24
The effect of DVBThe effect of DVB--C2 carrier levelC2 carrier level
Carrier signal level [dBµV]100 105 110 115 120
CIN
R/ M
ER [d
B] 55
50
40
45
CIN
R/ M
ER [d
B] 55
50
40
45
-9
-4
-5
-6
-8
-7
-9
-4
-5
-6
-8
-7
LOG
(BER
)
• random IM noise• impulse noise• cluster beats• thermal noise
• cluster beats• thermal noise
A C
BERAWGN
BERMeasured
(random IM noise) cluster beats
thermal noise
•••
B
Copyright © ITRI 工業技術研究院25
IntermodulationsIntermodulations
Output level (dB)0 10 20
Hybrid 2
CIN
R(d
B)
measurementsimulation
Output level (dB)0 10 20
Hybrid 1
CIN
R(d
B)
measurementsimulation
Output level (dB)0 10 200 10 20
Hybrid 2
CIN
R(d
B)
measurementsimulationmeasurementsimulation
Output level (dB)0 10 20
Hybrid 1
CIN
R(d
B)
measurementsimulation
Output level (dB)0 10 20
Hybrid 1
CIN
R(d
B)
measurementsimulation
Output level (dB)0 10 200 10 20
Hybrid 1
CIN
R(d
B)
measurementsimulationmeasurementsimulation
CTBCSO
CIN
R(d
B)
measurementsimulation
Output level [dBµV]
CIN
R(d
B)
measurementsimulation
Output level [dBµV]
Hybrid 2
Output level (dB)0 10 20 30
Output level (dB)0 10 20 30
Hybrid 2
CTBCSO
CIN
R(d
B)
measurementsimulation
Output level [dBµV]
CIN
R(d
B)
measurementsimulation
Output level [dBµV]
Hybrid 2
Output level (dB)0 10 20 30
Output level (dB)0 10 20 30
Hybrid 2
CIN
R(d
B)
measurementsimulationmeasurementsimulation
Output level [dBµV]
CIN
R(d
B)
measurementsimulation
Output level [dBµV]
CIN
R(d
B)
measurementsimulationmeasurementsimulation
Output level [dBµV]
Hybrid 2
Output level (dB)0 10 20 300 10 20 30
Output level (dB)0 10 20 300 10 20 30
Hybrid 2
f1: 119 MHz f2: 420 MHz f3: 855 MHz
96 digital carriers
42 unmodulated carriers
Copyright © ITRI 工業技術研究院26
The effect of DVBThe effect of DVB--C2 carrier levelC2 carrier levelq Network load
in this example:v 20 aTVv 30 QAM/DOCSISv 43 DVB-C2v 8 MHz grid
q Requirements:v 7 dB implementation marginv Analog TV does not exceed IEC quality requirements for noise and
intermodulationq Results:v DVB-C2 transmission of constellations up to 4096-QAM supported by cable
networks with a margin of some 5 to 6 dB in N+15 scenariosv All digital based on DVB-C2 (4096-QAM) may be critical in some networks
Source: Dirk Jaeger, “DVB-C2 system aspect,” CableLabs winter Conference, Denver CO, 19 February 2010
Copyright © ITRI 工業技術研究院27
Efficient signal conversion from satellite or Efficient signal conversion from satellite or terrestrial link to DVBterrestrial link to DVB--C2 C2
1
2
6
OFDMModu-lator
DVB-S2-Frontend
DVB-S2Frontend.
L1 Co nfiguration
PSI/SIStuffin g
PSI/SIStuffin g
DVB-C2-ModulatorMPEG2-TS-Processing
DVB-S2-Recei-ver
StreamAdapt.
DVB-S2-Frontend
Data SlicingTime+ Freq-Interleaving
PSI/SIStuffin g
1024QAMCR=9/10
StreamAdapt.
1024QAMCR=9/10
StreamAdapt.
1024QAMCR=9/10
2 31 54 6
Data SlicingTime+ Freq-Interleaving
Data SlicingTime+ Freq-Interleaving
HFC
Data Slice 1..4 42.66Mbit/sData Slice 6 49.39Mbit/s
Total 269.44Mbit/s
L1 block
1
2
6
OFDMModu-lator
DVB-S2-Frontend
DVB-S2Frontend.
L1 Co nfiguration
PSI/SIStuffin g
PSI/SIStuffin g
DVB-C2-ModulatorMPEG2-TS-Processing
DVB-S2-Recei-ver
StreamAdapt.
DVB-S2-Frontend
Data SlicingTime+ Freq-Interleaving
PSI/SIStuffin g
1024QAMCR=9/10
StreamAdapt.
1024QAMCR=9/10
StreamAdapt.
1024QAMCR=9/10
2 31 54 6
Data SlicingTime+ Freq-Interleaving
Data SlicingTime+ Freq-Interleaving
HFC
Data Slice 1..4 42.66Mbit/sData Slice 6 49.39Mbit/s
Total 269.44Mbit/s
L1 block
Satellite transponders DVB-C2 channel Transponders 6 Data Slices 6 Transponder bit rate 4*?42.66 2*49.39 Slice bit rate (Mbit/s) 4*42.66 2*49.39 Transponder bandwidth (MHz)
5?27 33 Total C2 channel bit rate (Mbit/s)
5?42*66 +1?49.39 = 269.44
Modulation 8PSK QPSK C2 channel bandwidth (MHz)
32
Code rate 2/3 9/10 Modulation (CCM) 1024QAM 1024QAM Symbol rate 22 27.5 Code rate 9/10 9/10
DVB-C2 channelBW=32 MHz
Copyright © ITRI 工業技術研究院28
Coding and modulation on Service Level Coding and modulation on Service Level ““Low Power ModeLow Power Mode”” in in CPEsCPEs
IP Back-bone
OFDMModu-lator
L1 configurationDVB-C2-Phy , (CCM/VCM)
HFCStream Adapt.
Stream Adapt.
1024QAM, CR= 9/10
16QAM, CR=3/4
Stream Adapt.
Stream Adapt.
1024QAM, CR= 9/10
1024QAM, CR= 9/10
Data SlicingTime+Freq-Interleaving
Data SlicingTime+Freq-Interleaving
SPTS streams(MPEG2-TS)
DVB-C2 channel
L1 blockDataSlice widthvariable(VBR)
Stuffing data Slice(s)for constant overall datarate
Stream Adapt. 16QAM, CR=3/4MPEG2-TS
Demux
PSI/SI-Generation
DVB-T/T2Frontends
IP-Gateway
DVB-S/S2Frontends
Aux FEC/ModAux Data
CPLP Slice
MPTS streams(MPEG2-TS)
Common PLP (CPLP)
CPLP SliceStuffing Slice
Copyright © ITRI 工業技術研究院29
Interactive service transmissionInteractive service transmission
DVB-C2Mod
DVB-C2Mod
DocsisModem
DOCSISModem
STBDocsis Core
CMTSDocsis Core
CMTS
GigEBackbone
(IPTV, VoIP,Internet)
IP/MPEG2-TS
Remux
MPEG2-TSVODTV (SDV)
STB
IP/GSE
HFC Downstream
HFC Down-Stream (IP)
HFC Upstream
HFC UpstreamIPTV, Internet, VoIP,Other IP services…
MasterHeadendMaster
Headend
VOD
Parameter Value Comment OFDM carrier spacing 1/448us Due to 8 MHz channel raster Dx 24 OFDM carriers Due to GI = 1/128 Number of OFDM carriers 14160 Within the 32 M Hz C2 channel Start fr equency [MHz] 306.16 MHz Multiple of OFDM carrier spacing and Dx raster Number of carriers, bandwidth Data slice 1 (8 PLPs) Data slice 2 (8 PLPs) Data slice 3 (8 PLPs) Data slice 4 (8 PLPs)
Carr. Number 2424(t1), 3384(t2) 3384(t1), 2904(t2) 2904(t1), 2904(t2) 3384(t1),2424(t2)
Bandwidth [MHz] 5.41(t1); 7.55(t2) 7.55(t1); 6.48(t2) 6.48(t1); 6.48(t2) 7.55(t1); 5.41(t2)
Data rates [Mbit/s] Video group 1: 46(t1); 64(t2) Video group 2: 64(t1); 55(t2) Video group 3: 55(t1); 55(t2) Video group 4: 64(t1); 46(t2)
Data slice 5 (2 PLPs) 2064(t1); 2592(t2) 4.61(t1); 5.79(t2) Data group: 40.3(t1); 49.3(t2) One high speed Internet Service
Data Slice tuning positions [MHz] Data Slice 1-4
309.32 ; 315.64 ; 321.96 ; 328.29; 334.61
Equidistant distribution within the C2 channel
8 MPEG4 AVC Videos in each Video Group (6 x HD 10Mbit/s and 2 x SD 2Mbit/s)
DOCSIS: Data Over Cable Service Interface SpecificationCMTS: cable modem termination system
Copyright © ITRI 工業技術研究院30
PLP BundlingPLP Bundling
DVB-C2 channel
2 21 4
MasterHE
IP-Backbone
OFDMModu-lator
StreamAdap-tion.
Data SlicingTim+Freq-Interl.
L1Configuration
DVB-C2-Phy(CCM)
1024 QAMCR=9/10
1024 QAMCR=9/10
1024 QAMCR=9/10
HFC
Data SlicingTim+Freq-Interl.
Data SlicingTim+Freq-Interl.
L1 block
Buf-fer
Buf-fer
Buf-fer
200Mbit/sdata stream(Internet)
Application example for PLP bundling; transmission of a high data rate MPEG2 transport stream via several bundled Data Slices in a DVB-C2 channel
Copyright © ITRI 工業技術研究院31
MasterHeadend
IP-Backbone
OFDMModu-lator
L1 configurationDVB-C2-Modulator (using GSE)
Stream Adapt. 1024QAM, CR=3/4 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=3/4
Stream Adapt. 1024QAM, CR=3/4 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=3/4
Stream Adapt. 1024QAM, CR=3/4 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=8/9
Stream Adapt. 1024QAM, CR=8/9 Data Slicing, Time+Freq.- Interleaving
Stream Adapt. 1024QAM, CR=8/9
Stream Adapt. 1024QAM, CR=8/9 Data Slicing, Time+Freq.- InterleavingStream Adapt. 1024QAM, CR=8/9
IPTV streams
For user outlets with CNR=29dB
For user outlets with CNR=32dB
ACM using Variable Coding and Modulation ACM using Variable Coding and Modulation (VCM) in the DVB(VCM) in the DVB--C2 Modulator C2 Modulator
Copyright © ITRI 工業技術研究院32
Physical parameter comparisons Physical parameter comparisons between DVBbetween DVB--CC and DVBand DVB--C2 C2
DVB-C DVB-C2 Bandwidth (MHz) 6, 8 8~450, 6~338
Mode Constant Coding & Modulation
Variable Coding & Modulation
Modulation Single Carrier Multiple Carrier (4K)
Constellation 16, 32, 64, 128, 256-QAM 41, 16, 64, 256, 1024, 4096-QAM
FEC RS LDPC + BCH
Code rate N. A. 1/2, 2/3, 3/4, 4/5, 5/6, 8/9, 9/10
Interleavers Time Bit, Time, Frequency
GI N. A. 1/128, 1/64 Pilot N. A. Scatter, Continual, Edge 1 For use in Modulation for FECFrame Header and Preamble Header
Copyright © ITRI 工業技術研究院33
Capacity comparisons of DVBCapacity comparisons of DVB--C & DVBC & DVB--C2C2
DVB-C DVB-C2 DVB-C2 64-QAM 256-QAM 1024-QAM 256-QAM Guard Interval NA 1/128 1/128 FEC RS 9/10 LDPC + BCH 5/6 LDPC + BCH Symbol rate 6.875 MBaud NA NA Bandwidth 8 MHz 8 MHz 8 MHz SNR 29,7 dB 29.5 dB 22 dB 2 Capacity 50.87 Mbit/s 66,14 Mbit/s 1 49.01 Mbit/s NOTE 1: The relative capacity gain is 30,5% at a SNR of 29,7 dB (required for 256-QAM DVB-C) NOTE 2: The relative robustness gain is 25,9 % at 50 Mbit/s payload (as provided by 256-QAM DVB-C)
DVB-C (256-QAM) DVB-C2 (4096-QAM) 8 MHz channel 50,9 Mbit/s 79,39 Mbit/s 16 MHz channel 50,9 Mbit/s 81,40 Mbit/s, 2,46%* 24 MHz channel 50,9 Mbit/s 82,08 Mbit/s, 3,41%* 32 MHz channel 50,9 Mbit/s 82,42 Mbit/s, 3,84%* 64 MHz channel 50,9 Mbit/s 82,93 Mbit/s, 4,49%* * relative gain with reference to 4096-QAM in 8 MHz bandwidth
Further improvements of spectrum efficiency due to increased transmitter bandwidth
Potential capacity or robustness increase of DVB-C2 in relation to 256-QAM DVB-C
Copyright © ITRI 工業技術研究院34
ConclusionsConclusionsq Better performance v Increased throughput: 30% gain at SNR=29 dB v Increased robustness: 7dB less SNR at 50 Mbps throughput v Spectrum efficiency is 10.4 bps/Hz at most Ø 4096-QAM, 9/10, GI=1/128, 1 preamble, single PLP and single DS
q Data Slices for increased flexibilityv Flexible Data Slices combined to overall bandwidthv PLP bundling for big data pipes
q Notching for efficient interference mitigationq Variable & Adaptive Coding and Modulation for
best possible spectrum deploymentq C2 opens a new era that needs a lot of
modification of regulationsv e.g. Frequency allocation
Copyright © ITRI 工業技術研究院35
References References q Bart Brusse, “The DVB Project and DVB-C2 - An Introduction,”
DVB-C2 Face-2-Face meeting, Denver, CO, 10 February 2010q Dirk Jaeger, “DVB-C2 system aspect,” CableLabs winter
Conference, Denver CO, 19 February 2010q http://dvb.org/technology/dvbt2/index.xml
工業技術研究院Industrial Technology Research Institute
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