How To Define Hfc Technology

Size: px

Start display at page:

Download "How To Define Hfc Technology"

Melina Byrd
3 years ago
Views:

1 Cable network topologies and implications for evolutionary approaches 33 rd International conference and Exhibition PIKE 2008, Zakopane, 14 October 2008 Bart Brusse, ReDeSign Project Manager

2 Pressure on bandwidth in HFC networks increases rapidly Competition increases rapidly HFC networks are amongst the most cost effective infrastructures, but competitors increasingly match service offering on cable Service offering increases equally rapidly New services emerge (VoD, UGC, PVR, HDTV..) Converging services create new integrated service concepts Value of bandwidth increases How to transport an existing advantage into an all-digital world Slide 2

3 Defining new HFC technology requires a good understanding of current variety HFC markets are highly competitive and differ from country to country Legacy technologies Commercial and regulatory environment Cable operators can choose from many options but can be obliged to deploy certain technologies As a result of purchasing differently designed networks As a result of regulatory circumstances As a result of market demand As a result of competitive forces Slide 3

4 Part 2 of the ReDeSign questionnaire for operators focused on network architecture Most commonly deployed type of network Fiber core topology Fiber node topology Coaxial network Current design principles for new-build networks Transmission technologies used in upstream and downstream Filtering and monitoring techniques Signal levels and noise characteristics for downstream and upstream parts of the network Slide 4

5 The questionnaire reached its 30% target and shows balanced response 62 Operators targeted, representing 68,6 M subscribers 21 Operators responding, representing almost 21 M subscribers > subscribers (39,8 M subs) > < subscribers 22,5 M subs) > < subscribers (6,3 M subs) > subscribers (10,90 M subs) > < subscribers 7,52 M subs) > < subscribers (2,56 M subs) Respondents operators total more than 1/3 of operators in Europe, representing more than 30% of subscribers Response shows good balance between operator categories, closely approaching actual situation Slide 5

6 Variation in network topologies increases towards the lower network levels Fiber core topology Fiber node topology Coaxial topology Number of operators with: Two-level fiber core Single level fiber core No fiber core network Number of operators with: BC & NC combined Separate BC & NC BC only Number of operators with: Hybrid topology Star topology Tree-and branch topology Distribution topology Clear preferences for specific types of fiber core and fiber node topologies but not for a coaxial topology Different type of topologies in either level of the cable network do not directly relate to the size (# subscribers) of the operator, or to a specific region or market Slide 6

7 Fiber core topologies: mainly single level but no relevant differences between parameters Two types of fiber core network topologies (single and dual level fiber core) Very little differentiation in the relevant parameters Singel level fiber core Dual level fiber core Parameter Value Remarks Topology Single fibre core Nr of fibres per ring 48 Amount of wavelengths per fibre 2 Max fibre length 100 km Topology Ring Broadcast and narrowcast combined Yes Fibre type 100% single mode Hub with Airco Yes Bidirectional network Yes Redundancy Yes / No Both cases will exist Slide 7

8 Fiber node topologies: two reference architectures emerge Generally speaking BC & NC combined on the same fiber Parameter Average value Remark Type of Fibre node - Not relevant for a the description of a typical fibre node architecture. Broadcast only fibre nodes are not considered in the reference designs. A. # of homes passed per fibre node 600 / 2000 homes One should consider 2 values for the amount of homes passed. Max # homes passed per fibre node 2000/4000 homes 2 values should be considered. Nr of coax branches per fibre node on 4 One typical value is enough to cover most cases. average Nr of fibre per fibre node 2 / 6 Some networks have limited amount of fibres available (covered by the 2), other networks have more fibres (covered by the 6) Max distance between the hub and the fibre node - Parameter should not impact the work, in case values are required the values of 20 km and 60 km should be taken. Topology of fibre nodes - Not relevant for the definition of a typical network. Nr of fibre nodes in physical ring (if there - Not relevant for the definition of a typical network. is a ring) Redundancy Yes / No A future network should support redundancy, but with small impact on the network. Use of WDM - Goes together with the availability of fibre, not relevant for the definition of a typical network. Group size of BC + NC 500 / 1000 / 2500 Most networks are covered by these 3 reference values Nr of fibre node returns combined into 1 / 2 Some combine it, others not. the same fibre Digitised return - Not relevant for the definition of a typical network. Return stacking - Not relevant for the definition of a typical network. Return redundancy - Not relevant for the definition of a typical network. Return group size 250 / 500 / 2000 BC + NC Return Slide 8

9 Reference architectures show most variation in the coaxial parts of the networks Optical node Distribution Trunks End amplifier Tree-and-branch Hybrid Star Type of coaxial network Tree & Branch Hybrid Star Down stream Frequency edge 550, 862 Homes Passed per fiber node 400/ /1000/ ON Output Signal level (dbmv) 100/ / /112 C/IM ratio 60 db Coaxial branches per fiber node 1,2,3 1,2,3 2,4 Number Cascaded distribution amplifiers 3/4 2/3 2/3 Distribution Amplifiers + return 100% Number branches per distribution amplifier 3 Amplifier Output Signal level 102/ /110 98/108 C/IM ratio 60 db Distribution branch length (km per amplifier) 0,3 0,5 Distribution 200 MHz per 100 m 3 db Distribution branch above ground 0/100% 0/100% 0/100% Number cascaded trunk amplifiers Trunk Amplifier + return 100% Number of branches per trunk amplifier 3 - Amplifier Output Signal level (dbmv) C/IM ratio 60 - Trunk Length (km per amplifier) 0,3-0,6 - Trunk 200 MHz (db) per 100 m 3 db - Trunk above Ground 0 /100% - number end amplifiers per end branch 4 2 End amplifiers with return 100% end branch length 0,2 0,4 km 200 MHz per 100 m 3 6 db Drop cable above ground 0 100% 0/100% 0/100% #HP per End Amplifier 20/40 Amplifier Output Signal Level C/IM ratio 60 Slide 9

10 Downstream transmission technologies show a bit more variation than upstream Downstream (digital TV) Upstream absolute weighed (basic subs) weighed (digital subs) % of operators using 64 QAM only % of operators using 64 QAM & 256 QAM % of operators using 256 QAM only 64 QAM still relatively common 256 QAM deployed as well Combined usage most common among larger operators DOCSIS downstream 256 QAM QPSK (%) QPSK & 16 QAM (%) 16 QAM (%) QPSK, 16 & 64 QAM (%) 64 QAM (%) 16 & 64 QAM (%) Only 25 30% of operators use complete band (5-65 MHz) Either 3-4 channels, or 8 channels 3,2 MHz most common bandwidth Slide 10

11 Limited variation with respect to signal levels and SNR in upstream and downstream Typical signal level at wall outlet at 60 dbµv Variation between 53 and 70 dbµv Worst case levels around 45 dbµv, sometimes up to 55 dbµv Typical cable modem output signal level dbµv Acceptable worst case levels between 112 and 118 dbµv Typical downstream SNR value around 36 db (64 QAM) Average worst case value around 32 db Relatively large spread with worst case values as low as 25 db More variation in upstream Typical values from 24 to 38 db averaging 30 db Spread typical and worst case values per operator can be large Slide 11

12 Six reference architectures describe most of the cable networks in Europe Singel level fiber core Large fiber nodes Smaller fiber nodes BC + NC Return BC + NC Return Tree-and-branch Hybrid Star Transmission technologies and signal level/noise characteristics are important but as such less relevant to distinct between architectures Slide 12

13 Initial evaluation of options to expand capacity in HFC networks Statistical multiplexing QAM sharing Switched Digital Video Better modulation codes Extensions beyond 1 GHz Extensions to 1 GHz Network segmentation Analogue switch-off Deeper fiber solutions relevant for almost all operator Design principles reveal slight trend towards smaller nodes Starting positions for migration towards a next generation HFC network can be quite different combinations with other solutions to increase capacity will have to generate tailored solutions Slide 13

14 Market developments may influence upgrading technology combinations as well Questionnaire results do not show significant connection between reference architectures and short mid term upgrade concepts Regional (market driven) differences may be more relevant Slide 14

15 Cable network reference architectures & evolutionary concepts: conclusions Cable networks shows considerable differences across Europe but can be described through 6 reference architectures Fiber node size & coaxial topology most relevant parameters Other aspects (e.g. transmission technologies) less relevant Further segmentation is mostly preferred by most operators Seconded by 5 technically less disruptive technologies Combinations with other concepts that do not directly affect the architecture are likely to be most effective No clear relationship between an operator s preference for technology-combinations and its network architecture, but Further research is expected to reveal these combinations Regional differences and differences in market development will most likely be a relevant element as well Slide 15

16 Thank you For further information:

Investor & Analyst Conference Technical Presentation. Jan Vorstermans

Investor & Analyst Conference Technical Presentation Jan Vorstermans Mechelen - May 13, 2008 Agenda The current network The challenge The actions Cable versus DSL Research & Standardization Capex Conclusion