Measuring Digital and DOCSIS Performance .


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Measuring Digital and DOCSIS Performance. Randy Francis JDSU. Today’s Agenda. Definitions / Background Digital Signals / QAM DOCSIS 1, 1.1, 2.0. 3.0 (Data Over Cable Service Interface Spec.) VoIP Digital Testing/Troubleshooting MER, BER, QAM Ingress, Equalizer Stress,
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Measuring Digital and DOCSIS Performance Randy Francis JDSU

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Today\'s Agenda Definitions/Background Digital Signals/QAM DOCSIS 1, 1.1, 2.0. 3.0 (Data Over Cable Service Interface Spec.) VoIP Digital Testing/Troubleshooting MER, BER, QAM Ingress, Equalizer Stress, C/N versus BER versus MER Constellations/Symbols and Digital Bits, Phase Noise DOCSIS & IP Testing Packet Loss, Throughput VoIP Testing Voice Quality Measurements, E-Model, Delay, Packet Loss, Jitter VoIPCheck Testing, PacketCable Testing Return Path Why screen it? RF Trending Results Ingress & Leakage Q and A Quiz Time

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Acronyms & Terms QAM -Quadrature Amplitude Modulation Symbols -Collection of Bits Symbol Rate -Transmission Speed I & Q -Components of QAM information Constellation -Graph of QAM Data MER -Modulation Error Ratio BER -Bit Error Rate FEC -Forward Error Correction

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A Typical Home Installation a common home establishment TAP House TV Drop Cable High Pass Filter TV GROUND BLOCK 3-Way 2-Way Splitter TV CABLE MODEM

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Why Go Digital? Effectiveness Source signs are advanced Standard and High Definition TV (SDTV, HDTV) High Speed Data and Digital Video is more proficient than simple Transmit likeness 6 to 10 simple channels (VCR quality) more than one 6 MHz transfer speed Quality Better Picture and Sound Quality Less Susceptible to commotion Error identification and amendment is conceivable Flexibility Data effortlessly multiplexed into computerized flag Higher Data Security

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01 00 10 11 What is Digital? Source and Destination is advanced information Assign one of a kind examples of 1\'s and 0\'s Transmission way is by means of a simple bearer Choice of regulation is the one that enhances transfer speed (information versus recurrence \'space\') and flexibility to commotion Generate Digital Receive Digital Transmit Analog

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The Carrier, incidentally, is ANALOG Modulation Analog Content – Analog Carrier Digital Content – Analog Carrier

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Good Digital TV, DOCSIS, Digital Voice all utilization SAME sort of RF Modulation – QAM Same estimations apply Signal level, Modulation Error Ratio, Bit Error Rate, in-band recurrence reaction, are all comparable, if not indistinguishable. Terrible Each administration has distinctive edge of weaknesses What is observable in Digital voice may not be noticeable in DOCSIS, what is troublesome in DOCSIS is unique in relation to advanced video. Some uplifting news… and some awful news

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QAM and CATV 16 QAM is a piece of the DOCSIS ® 1.0/1.1 upstream particulars 64 QAM and 256 QAM is utilized for both advanced video and DOCSIS downstream , permitting more computerized information transmission utilizing a similar 6 MHz transfer speed Transmit likeness 6 to 10 simple stations (VCR quality) more than one 6 MHz transfer speed DOCSIS is the Standard for information over Cable frameworks give higher flag to commotion proportions than over-the-air transmission. A very much outlined and kept up link plant meets these QAM flag to clamor prerequisites.

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QAM Data Capacity (Annex B) QAM 256 permits ~ 2 more channels versus QAM 64 No Real Cost Advantages Why not go all QAM 256?

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DOCSIS® What is it? What contrasts among renditions?

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DOCSIS Defined? DOCSIS Definition CableLabs® Certified Cable Modem Project Data Over Cable Service Interface Specification Not required yet profoundly clung to standard – permits interoperability Data over an advanced QAM flag Digital flag Downstream typically 64 or 256 QAM Upstream normally QPSK or 16 QAM Uses Data Packets Information broken into lumps Asymmetrical correspondence More Info Downstream Less Info Upstream Digital "sheaf"

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DOCSIS ® Versions at a Glance DOCSIS 1.0 (High Speed Internet Access) 23 million items transported worldwide as of YE2002 228 CM Certified, 29 CMTS Qualified DOCSIS 1.1 (Voice, Gaming, Streaming) Interoperable and in reverse perfect with DOCSIS 1.0 "Nature of Service" and element benefits, a MUST for PacketCable™ In the field NOW - 64 CM Certified, 22 CMTS Qualified DOCSIS 2.0 (Capacity for Symmetric Services) Interoperable and in reverse perfect with DOCSIS 1.x More upstream limit than DOCSIS 1.0 (x6) & DOCSIS 1.1 (x3) Improved heartiness against impedance (A-TDMA and S-CDMA) Available NOW – Number of CM & CMTS Qualified developing DOCSIS 3.0 (Channel Bonding) Interoperable and in reverse perfect with DOCSIS 1.x & 2.0 Specification discharged not long ago – Devices not yet accessible Good Resource Site: www.cablelabs.org

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DOCSIS 1.1 Overview Interoperable with DOCSIS 1.0, or more… Enhanced "Nature of Service" (QoS) Guarantees and additionally restrains for information rates (ex. Gold, Silver administration levels) Guarantees for inertness Improved security - intended to diminish plausibility of "burglary of administration, give secure programming downloading." – BPI+ (Baseline Privacy Plus) Interoperability - DOCSIS 1.0 and DOCSIS 1.1 link modems and CMTSs on a similar plant. Better operation and OSS highlights Transmit Equalization - more strong transmission Max Modulation 256 QAM Downstream (~40Mbps) 16 QAM Upstream @ 3.2MHz (~10Mbps)

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DOCSIS 2.0 Overview – Key Upstream Advances Symmetrical administrations are empowered by DOCSIS 2.0 1.5x more noteworthy productivity works at 64 QAM 2x more extensive stations new 6.4 MHz wide station 3x preferable upstream execution over V1.1 6x preferred upstream execution over V1.0 DOCSIS 2.0 enlarges the pipe for IP activity, permitting link suppliers to make progressively and better administrations for voice, video, and information It does this by utilizing upgraded regulation and enhanced mistake revision Superior entrance and motivation clamor execution 100% in reverse good with DOCSIS 1.0/1.1

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DOCSIS 3.0 Overview Specification before the end of last year DOCSIS 3.0 Interface Specifications (Released December 2006) CPE hardware being developed stages Downstream information rates of 160 Mbps or higher Channel Bonding at least 4 channels Upstream information rates of 120 Mbps or higher Channel Bonding at least 4 channels Internet Protocol rendition 6 (IPv6) Current System (IPv4) is constrained to 4.3B numbers IPv6 extraordinarily grows the quantity of IP locations Expands IP address measure from 32 bits to 128 bits IPv6 bolsters 3.4×10 38 addresses; Colon-Hexadecimal Format 100% in reverse perfect with DOCSIS 1.0/1.1/2.0 256QAM => ~40Mbps 4 x 256QAM => ~160 Mbps 64QAM => ~30Mbps 4 x 64QAM => ~120 Mbps 4923:2A1C:0DB8:04F3:AEB5:96F0:E08C:FFEC

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DOCSIS 3.0 – Channel Bonding Individual QAM 256 DOCSIS channel Versions 1.0/1.1/2.0 utilized just a single channel for upstream and one channel for downstream interchanges 256QAM => ~40Mbps 4 Bonded QAM 256 DOCSIS channels DOCSIS v3.0 Spec obliges gadgets to have the capacity to security at least 4 upstream channels into one and 4 downstream channels into one for 4 times expanded throughput in both bearings The MSO does not need to utilize every one of the 4 channels, but rather the gadgets which are 3.0 consistent must be able to security at least 4 diverts in both headings 4 x 256QAM: 4 x 40Mbps = 160 Mbps

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Digital Testing and Troubleshooting How? What does it mean?

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QAM Digital Measurements Spectrum & Digital Average Power Level MER QAM Pre/Post FEC BER Constellation Display Advanced Tests QAM Ingress Under The Carrier Group Delay In-Channel Frequency Response Equalizer Stress (Adaptive Equalization)

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QAM Digital Measurements Measuring the nature of QAM computerized transporters is altogether not quite the same as measuring simple bearers. Estimation of advanced bearers is imperative to decide how shut the transporter is to coming up short (how much edge) since there might be no quality corruption.

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Digital Average Power Level Measurements Digital Average Power Measurements and Measurement Bandwidth The range analyzer view is a brilliant device to see cautious RF-bearers. Alert is required when seeing computerized adjusted signs (sheaf). The flag\'s level estimation is gotten from the chose estimation data transfer capacity (determination transmission capacity). At a RBW of 300 kHz, a 64QAM - 6 MHz wide advanced flag peruses in the range analyzer follow 3 dB too low. The Average Power standard takes little cuts from the incorporated RF-vitality, summing them together to one aggregate power perusing in the LEVEL-mode. Simple and advanced (communicate) QAM flag. The suggested delta in level ought to be 6 to 10 dB.

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Measuring the Digital "Sheaf" Non measured range in view of 280 kHz step estimate inside 6 MHz add up to Bandwidth Digital transporter under test (6 MHz BW) IF Measurement Bandwidth = 280 kHz Summing cuts of the aggregate coordinated vitality 0 Frequency - 2.5 MHz +2.5 MHz +/ - 140 kHz

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Measuring the Digital "Pile" Measuring the Average Level of the Digital Haystack Measuring the Peak Level of the Digital Haystack 6 MHz Bandwidth control 280 kHz Bandwidth control

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Digital – more than simply dB\'s MER and Pre and Post BER estimations are critical to guaranteeing Digital Quality

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Modulation Error Ratio (MER) Analogous to S/N A measure of how images (I versus Q) are really set, contrasted with perfect position MER(dB) = 20 x log RMS blunder size normal image greatness Good MER 64 QAM: 28 dB MER 256 QAM: 32 dB MER Average image extent RMS mistake size

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More MER Modulation Error Ratio (MER) in advanced frameworks is like S/N or C/N utilized as a part of simple frameworks MER decides how much edge the framework has before disappointment Analog frameworks that have a poor C/N appear as a "frigid" picture A poor MER is not perceptible on the photo straight up to the point of framework disappointment - "Bluff Effect" Can\'t utilize the TV as a bit of test gear any longer

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Digital TV Waterfall Graph

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No FEC C/N versus BER versus MER

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" MER" is to Digital, what flag to commotion is for simple MER is influenced by high clamor, low sign

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