docsis 3 0 us planning bandwidth management l.
Skip this Video
Loading SlideShow in 5 Seconds..
DOCSIS 3.0 US Planning & Bandwidth Management PowerPoint Presentation
Download Presentation
DOCSIS 3.0 US Planning & Bandwidth Management

Loading in 2 Seconds...

play fullscreen
1 / 19

DOCSIS 3.0 US Planning & Bandwidth Management - PowerPoint PPT Presentation

  • Uploaded on

DOCSIS 3.0 US Planning & Bandwidth Management. John Downey, Consulting Network Engineer – CMTS BU . Co-Sponsor – CCI Systems. Cisco Gold Partner End-to-end network services Network and headend engineering Network mapping Network construction (cable/fiber) Network maintenance NOC services.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'DOCSIS 3.0 US Planning & Bandwidth Management' - Sophia

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
docsis 3 0 us planning bandwidth management

DOCSIS 3.0 US Planning & Bandwidth Management

John Downey, Consulting Network Engineer – CMTS BU

co sponsor cci systems
Co-Sponsor – CCI Systems
  • Cisco Gold Partner
  • End-to-end network services
    • Network and headend engineering
    • Network mapping
    • Network construction (cable/fiber)
    • Network maintenance
    • NOC services
co sponsor todd gingrass cci systems
Co-Sponsor – Todd Gingrass, CCI Systems
  • Vice President of Network Technology
  • 14 years at CCI Systems. 
  • Bachelor of Electrical Engineering degree from Michigan Technical University 
  • Certifications include Cisco Certified Network Associate Routing & Switching (CCNA), Cisco Certified Design Associate (CCDA), and Cisco Certified Internetwork Professional (CCIP) 
  • A member of the Society of Cable and Television Engineers (SCTE) and Institute of Electrical and Electronics Engineers (IEEE)
presenter john downey cisco
Presenter – John Downey, Cisco
  • 20 years in the data/telecommunications/ networking industry
  • BS in Electrical Engineering from Penn State University.
  • Nine years with Cisco as a Broadband Network Engineer presently with the Cable Modem Termination System (CMTS) Business Unit.
  • Certifications include CCNA and CCCS. 
  • An SCTE member since ’96.
  • Frequency Stacking Levels
    • What is CM max US output with four channels stacked and do channels have to be contiguous?
  • Power/Hz & laser clipping
  • Diplex Filter Expansion to 85 MHz?
    • Amplifier upgrades occurring now; Best to make 1 truck roll
    • Think about diplex filters, line EQs, step attenuators, taps, etc.
business objectives
Business Objectives
  • Allow more BW for DOCSIS 1.x & 2.0 CMs
  • Limit/reduce more node splits
  • Introduce new HSD service of 50 to 100 Mbps
  • Allow migration of existing customers to higher tier and DOCSIS 3.0 capability
    • Better Stat Muxing
atdma general deployment recommendations
ATDMA General Deployment Recommendations
  • After increasing CW to 6.4 MHz, measure & document unequalized US MER at multiple test points in the plant
    • Use PathTrak Return Path Monitoring System linecard
    • Or Sunrise Telecom Upstream Characterization toolkit
  • 25 dB or higher Unequalized MER is recommended
    • Less than 25 dB reduces operating margin
    • Check US MER as well as per-CM MER
  • Pick freq < 30 MHz away from diplex filter group delay
  • Make sure latest IOS version is running on CMTS
  • Turn on Pre-Equalization
us mer snr issues
US MER(SNR) Issues
  • Increasing ch width from 3.2 to 6.4 keeps same average power for single carrier
    • SNR drops by 3 dB or more
  • Keeping same power/Hz could cause max Tx level from CMs and/or laser clipping/overload
  • Equalized vs unequalized MER readings
  • Modulation profile choices
    • QPSK for maintenance, 64-QAM for Data, 16-QAM for VoIP?
    • Max output for 64-QAM is 54 dBmV
      • Cab up n power-adjust continue 6
  • Pre-EQ affect
    • Great feature in 1.1 & > CMs, but could mask issues
d3 0 us issues
D3.0 US Issues
  • Frequency Stacking Levels
    • What is the max output with multiple channels stacked
    • Is it pwr/Hz & could it cause laser clipping?
  • Diplex Filter Expansion to 85 MHz
    • If amplifier upgrades are planned for 1 GHz, then pluggable diplex filters may be warranted to expand to 85 MHz on the US
    • Still must address existing CPE equipment in the field and potential overload
    • RFoG could be perfect scenario (maybe even 200 MHz split)
  • CM must be w-online (requires 1.1 cm file) for US bonding
  • Monitoring, Testing, & Troubleshooting
    • Just like DOCSIS 2.0, now test equipment needs to have D3.0 capabilities
us frequency and level issues
US Frequency and Level Issues
  • Freq assignments
    • 5 to 42, 55, 65, 85 MHz ?
      • Diplex filters, line EQs, step attenuators, CPE overload
  • Max Tx for D2.0 64-QAM for 1 ch is 54 dBmV
  • D3.0 US ch max power
    • Tx for D3.0 TDMA
      • 17 - 57 dBmV (32 & 64-QAM)
      • 58 dBmV (8 & 16-QAM)
      • 61 dBmV (QPSK)
    • Tx for D3.0 S-CDMA
      • 17 - 56 dBmV (all modulations)
  • Max Tx per ch for 4 freqs stacked at 64-QAM ATDMA is only 51 dBmV & 53 for S-CDMA
total power
Total Power
  • Was only one US channel present, now up to four US chs transmitting at same time
    • Possibly 6.4 MHz each; nearly 26 MHz US channel loading
  • Lots of power hitting return path fiber optic transmitter
  • Probability of laser clipping is increased, especially if using legacy Fabry-Perot (FP) lasers
    • Good idea to upgrade to Distributed Feedback (DFB) lasers, which have significantly more dynamic range
  • Use return path monitoring system capable of looking above 42 MHz to see second and third order harmonics
  • Any burst noise above diplex filter (i.e. 42 MHz) coming out of return path receiver is usually indicative of laser clipping
laser clipping
Laser Clipping
  • Blue trace shows case of strong laser clipping
  • Green line represents flat US laser noise floor with no clipping
  • Note that this US has four US bonded channels
channel placement
Channel Placement
  • Each US channel used for bonding is individual channel
  • Transmitters (channels) are separate
    • Don't have to be contiguous and can have different physical layer attributes like; modulation, channel width, tdma or scdma, etc.
  • Frequencies can be anywhere in US passband and do not need to be contiguous
  • It may be wise to keep relatively close so plant problems like attenuation and tilt don’t cause issues
  • CM will have some dynamic range to allow specific channels to be a few dB different vs. other channels
new architectures
New Architectures
  • New conundrum raised when fiber run deeper into network
    • RF over Glass (RFoG)
    • DOCSIS Passive Optical Networks (DPON)
  • May incorporate 32-way optical splitter/combiners. Having a laser Tx in your house combined with 32 other houses feeding 1 Rx in the HE is addressed with lasers timed with the actual traffic from the house; unlike how it is done today where the US laser is on all the time
  • US bonding and/or load balancing presents potential issue where an US laser could be transmitting same time as another US laser
  • May be acceptable with multiple lasers transmitting same instant in time, if they are carrying different frequencies,
  • Will S-CDMA pose same problems? This multiplexing scheme allows multiple CMs to transmit same instant in time
us load balance isolation example

Fiber Optic

Rx 1



@ 24 MHz



@ 31 MHz

Fiber Optic

Rx 2



@ 24 MHz


US Load Balance & Isolation Example
  • Attempting to “share” one US port across two other US ports
    • Can cause isolation issues
    • Load balance issues (ambiguous grouping)
system levels reverse

17 dB at 5 MHz & 32 dB at 1 GHz

    • Eliminates max transmit CMs
    • Eliminates high DS tilt to TV

CS(CEQ) tap

FEQ w/ US pad










1.5 dB

Step Attenuator or EQ tap




43 dBmV







level @ the tap

PIII .5” cable

.40 dB @ 30 MHz

System Levels Reverse

A total design variation of ~14 dB!

transmit level possibilities
Transmit Level Possibilities
  • Running D3.0 CM in low modulation scheme allows higher power
  • Use D3.0 CM in 2.0 mode
    • Single frequency on D3.0 CM offers 3 dB higher power
  • Using SCDMA with more codes may also allow higher Tx power, but depends on implementation
  • Minimum level of 17 dBmV (24?) could cause issues in lab environment or HE test CM
    • Pmin = +17 dBmV, 1280 ksym/s
    • Pmin = +20 dBmV, 2560 ksym/s
    • Pmin = +23 dBmV, 5120 ksym/s
  • Cost effective and faster time to market
    • Decrease costs today – deploy DOCSIS 3.0 later with no additional CMTS investment!
  • Targeted insertion of D3.0
    • Leverage existing US chs while adding more US capacity
    • Load balance 1.x/2.0 and enable D3.0 when needed
    • Minimizes capex & opex
  • Leverage D3.0 bonding for D2.0 tiers & services
    • Better stat-mux efficiency
    • Improved consumer experience
summary cont
Summary (cont)
  • Long term D3.0 service planning
    • Insure optimized frequency allocation
    • Enable seamless upgrade to higher D3.0 tiers
    • Wire once
    • Add QAM chs as tiers or service take-rates go up
  • End-to-end solution minimizes risk
    • CMTS, QAM, and CPE
  • Account for physical connectivity, not just channel capacity
    • May not be advantageous to combine noise to satisfy connectivity