Cable Network Overview Presented by: Ma1 Schmi1 (CableLabs)
Contributors & Supporters Alphabe?cal by First Name Alberto Campos, CableLabs Edwin Malle1e, Bright House Networks Eugene Dai, Cox Communica?ons George Hart, Rogers Communica?ons Jack S. Burton, Cablevision Jeff Finkelstein, Cox Communica?ons Joe Solomon, Comcast John Bevilacqua, Comcast John Dickinson, Bright House Networks Jorge Salinger, Comcast Kevin Noll, Time Warner Cable Kirk Erichsen, Time Warner Cable Ma1 Schmi1, CableLabs Michel Allard, Cogeco Cable Mike Darling, Shaw Communica?ons Saif Raman, Comcast Volker Leisse, Cable Europe Labs 3/6/12 2
Introduc?on This slide deck is intended to provide an overview of the following: How cable networks have evolved over?me The components of an HFC network Main sources of impairments in HFC networks and their impact on opera?ons How the cable network s spectrum is divided up into different services, and how that may change over?me Please note that these slides are merely representa?ve, and do not necessarily depict actual cable systems 3/6/12 3
United States Cable Statistics 114 million households, 131.7 million housing units 129.3* million homes passed by cable video service (~98%) 124.3* million homes passed by cable high speed data service (~93%) Ubiquitous coverage of high speed data services * Sta?s?cs by NCTA June 2011 4
Cable Networks: Then and Now From Amplifier Headend Coax Trunk Cable Coax Feeder Cable Tap Tree and Branch Drop Cable To Hub Node Node Node 50-500 Homes Master Headend/ Data Center Node Ring- Star- Bus Node Node Hub Redundant Fiber Ring Hub Fiber Regional HUB Home Architecture Node Node Node Coax Trunk Amplifier Tap Drop Cable Coax Feeder 3/6/12 5
Node + N Generic Implementation Headend Opt. Tx/Rx Analog Tx over Fiber Fiber Fiber Fiber Node Rigid Coax Trunk Amp. Taps Rigid Coax CPE CPE Multi-port Amplifier CPE CPE Taps Amplifier CPE CPE CPE Bridger Amplifier CPE Line Extender Amplifier Drop Cable CPE Home Network 3/6/12 6
Op?cal Node Downstream Blue Upstream Red 3/6/12 7
Mul?port and Line Extender Amplifier Structure MulJport Amplifier Line Extender Amplifier 3/6/12 8
Distribu?on Tap Downstream DirecJon Drop Ports 3/6/12 9
Plant Impairments RETURN Diplexer DOWNSTREAM Provisioning and Management Headend Fiber CMTS Opt. Tx/ Rx Fiber Narrow-band interferers Laser Clipping Rigid Coax Fiber Node 5 42 50 550 Cable Modem Upstream Micro-reflection End-of-Line Issues Rigid Coax 4-6 Taps ANALOG Impulses CTB & CSO DIGITAL Cable Modem Downstream 870-1002 Primary Signal Reflected Signal Corroded connector (CPD) Isolation Coaxial Cable Tilt Cascading Amplifiers (GDD & roll-off) In-Line Equalizer (GDD & Tilt) Drop Cable CM In home issues Home Wiring 3/6/12 10
Impulse /Burst Noise Generated mostly from external sources entering via ingress Arise through cable defects in proximity of noise sources such as electric motors, appliances, thermostats, arc welders, light fixtures, power lines, sta?c from lightning etc. Typically last a few microseconds and covers a good por?on of spectrum Burst noise related to laser clipping and overdriving amplifiers can have dura?ons a long as a data burst.
Narrowband Interferers in Upstream Spectrum Narrowband interferers and wideband noise determines possible modulation efficiencies Carrier Level CNR 16QAM 64QAM 256QAM Noise 6 10 14 18 22 26 30 34 38 42 5 Frequency in MHz
Fiber Node Loss Comparison Coax Loss Tap Insertion Loss Attenuation (db) 30 25 20 15 10 5 0 Amplifier ES 1 1000 Feet 0.625 1000 Feet 0.500 300 Feet RG6 150 Feet RG6 0 300 600 900 1200 1500 Frequency - MHz 23 20 17 14 11 8 N Feet Tap to Tap Spacing Tap Coupling Loss Drop Cable Loss ES = End Sta?on or CPE ES 2 Decreasing tap values give each ES approximately same performance 3/6/12 13
Example Channel Spacing 5 MHz 750 MHz 42 MHz 54 MHz 130 MHz 550 MHz - 1 GHz Noisy (unused) STB OOB Data, Voice Analog Channels STB OOB Analog Channels Digital Channels VOD, SDV Data, Voice Lower Adjacent Channel Channel Tuned Upper Adjacent Channel One 256 QAM Downstream 6 MHz Digital Channel carries ~40 Mbps 1 GHz System contains ~ 158 6 MHz Downstream channels 54 MHz 60 MHz 66 MHz 72 MHz 6MHz One 64 QAM Upstream 6.4 MHz Digital Channel carries ~30 Mbps 3/6/12 14
2008 Example Frequency Alloca?on Example frequency alloca?on circa 2008; free channels typically do not exist today 1 Analog channel 10-12 SD Digital channels 2-3 HD Digital channels 10 SD VOD streams 2-3 HD VOD 1 DOCSIS Channel 1 Telephony Channel = or or or or or or 1 Control channel or 1 SDV channel Equivalent channel capacity 3/6/12 15
2008 Example Channel Alloca?on Figures 3/6/12 rounded up 16
Spectrum Usage Over Time (not to scale) Where are we going with spectrum? 750 MHz System Example HSD/Voice VOD HSD/Voice VOD Some IP Video HSD Voice IP Video Broadcast ADS HD SD Analog SDV SO ADS HD SD VOD ndvr SDV SO ADS HD HSD Voice VOD SDV SO ndvr ADS Narrowcast SD HD Past Analog Analog SD Today Soon Future 3/6/12 17
Addi?onal Notes/Informa?on STBs receive informa?on and communicate to the network in one of two ways Older STBs transmit on a proprietary channel, and receive guide data on a Forward Data Channel tunable up to 130 MHz (see SCTE 55 for details) Newer STBs support both SCTE 55 and the use of DOCSIS channels for signaling Most receivers (in STBs, TVs with QAM tuners, etc.) use wideband Automa?c Gain Control equipment As a result, they receive signals across the en?re spectrum, and may be sensi?ve to nearby high power transmissions 3/6/12 18
Ques?ons? 3/6/12 19
Background Material 3/6/12 20
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Node Topology Example 3/6/12 22