4096-OFDM Implementation on the HFC plant with Fiber Deep and Distributed Access Architecture. Maxwell Huang

Transcription

1 4096-OFDM Implementation on the HFC plant with Fiber Deep and Distributed Access Architecture Maxwell Huang

2 Study on 4096-OFDM Implementation on R-PHY + FD Architecture Remote PHY + Fiber Deep Architecture 4096-QAM =12 bit / symbol =58.4Mbps / 6MHz 42dB MER required Lower to 36dB by OFDM w/ LDPC 4096-OFDM implementation over entire HFC plant becomes feasible because CNR is improved significantly by R-PHY. Distortion and noise are significantly improved by FD. MER distribution becomes consistent over the entire plant by R-PHY+FD. Device MER (db) Room Temp. Over Temp. R-PHY Power Amplifier CPE EOL MER EOL MER Estimate

3 Study on PAPR Increase CCDF Comparison Probability All SC- QAM 6*4096-OFDM 10% % % % % % Peak PAPR and Compression OFDM suffers the more degradation in MER than QAM when power amplifier operates close to its maximum output power. Assume 2dB degradation in the MER caused by compression due to PAPR Device MER (db) Room Temp. Over Temp. R-PHY Power Compression CPE EOL MER (db) EOL MER Estimate May not support 4096-OFDM

4 Partial Band CFR _ A Solution Under Investigation Adaptive Baseband Proposed solution to PAPR reduction: Applying the Crest Factor Reduction (CFR) technique such as Adaptive Baseband on the partial band. e.g. ONLY for highest OFDM (channel A). Reasoning: Partial band CFR still effectively reduces PAPR but mitigating the trade-offs in performance and computational complexity. Apply the Adaptive Baseband on OFDM channel A

5 Study on Power Increase R-PHY + FD architecture could bring an unprecedented thermal challenges for the node because Roughly 25 watt of DC power increase results from enabling the super high output capability needed for fiber deep deployment. Roughly 20Watt DC power increase results from introducing R-PHY module in the node.

6 A proposed power saving solution The Dynamic Power Saving feature makes the bias current adjustable in field, so that node can smartly set the bias current according to the actual cable losses and the change in spectrum loading. APSIS Compliant Power saving associated with cable loss distribution Power saving associated with Spectrum Loading

7 Thank You!

8 The Capacity of Analog Optics in DOCSIS 3.1 HFC Networks Michael He John Skrobko, Wen Zhang, Qi Zhang

9 Measured Upstream NPR for Multiple Loads 12 db DR 12 db DR 24 db DR Note: 1. The US Rx optical input power is -13 dbm. The EIN of US analog Rx is 1.3pA/ Hz. 2. Typically the US optical link required min. NPR dynamic range (DR) is 12 db.

10 Thermal Noise Contributes more to CNR at Low OIP 9.5dB Constellation (QAM) Required CNR (db) US OFDMA US Min OIP (dbm) 5-85 MHz MHz (measured) dbm Note: 1. OMI (5%/6.4MHz) for this example is chosen for MHz loading. The EIN is 1.3pA/ Hz. 2. The US Min OIP results (in table) are in meeting the Required CNR with 12 db of dynamic range, and are extrapolated base on the measured NPR DR at -13 dbm

11 WDM Demux Link budget (db) Link Budget vs. Fiber Deep Requirements Probable Fiber Deep Optical Link Tx 1 Tx 2 Tx n WDM Mux Fiber link (40km) Rx 1 Rx 2 Rx n Downstream (up to 1218 MHz) Upstream (5-204 MHz) Loss (db) Total: 15 Analog (moderate order) Analog (high order) 10G Digital Note: 1. Assuming output power of analog Tx DS(US) is 10 dbm (3 dbm) for link budget calculation. 2. Assuming 10GE optical transmission link budgets is with the EML Tx minimum output of 0 dbm, and APD Rx receiving sensitivity of -21 dbm (w/ 2dB fiber dispersion penalty). 2K-qam 4K-qam R-phy 512-qam 1K-qam R-phy/EDR

12 Summary CNR of analog optical links is dominated by EIN of the optical Rx at low optical input power. Analog optical link is still workable for 4K-qam OFDM DS (up to 1218 MHz) at -2dBm OIP, while for 1K-qam OFDMA US (5-204MHz) at -13dBm OIP. Digital optics can support 4K/1K OFDM/OFDMA with 9 db and 5 db more link power budget than DS/US analog optics, respectively.

13 Thank You Michael He Cisco Systems

14 DOCSIS 3.1 Profile Management Application and Algorithms Greg White, Karthik Sundaresan (CableLabs)

15 D3.1 Profiles & Creation Problem N-Dimensional Vectors Modulation Profile: Vector of modulation orders CM MER: Vector of reported signal quality How to choose best profiles? CMTS supports up to 16 profiles per channel Profile A : lowest common denominator Dimensionality Problem N = 3800 or 7600 subcarriers possible profiles (8 bit - 14 bit Modulations) choose-15 = ~ possible 16-profile sets Simplifying assumptions don t help

16 D3.1 Profiles : Objective Function What function are we trying to maximize? GGGGGGGG JJ = channel capacity using set of profiles P channel capacity using only profile A JJ PP,AA = KK AA 1 Φxx xx PPKKxx Φ x = N x /N (fraction of users assigned to profile x) K x = sum of bit-loading values (all subcarriers) for profile X

17 Optimization Methods (1): PCA Profile Coalescation Algorithm

18 Optimization Methods (2): K-Means Clustering using K-Means

19 Optimization Methods (3): KCA K- Means PCA KCA Start with K-Means to quickly get initial clusters Use PCA to reduce to optimal set of profiles

20 Algorithm Comparison KCA : best choice for fast runtime Use PCA to reduce to profiles using K-Means

21 DOCSIS 3.1 Multicast Profile Management Mechanism Evan Sun Ph.D. Standard Engineer

22 Multicast Profile Management Multicast Profile (MP) Optimization Prerequisite CM joins or Leaves multicast group Internal Profile Management CM joins or leaves procedures External Profile Application Interfaces between the PMA and CMTS

23 MP Optimization Trigger Conditions CMTS Multicast Group One Multicast Group Two CM A CM B CM C CM D Client 1 Client 2 CM is working on DOCSIS 3.1 mode with OFDM downstream channel; First Client connected with CM wants to join the multicast group; Last Client connected with CM leaves the multicast group.

24 Internal Profile Management CM Joins Multicast Group CM Leaves Multicast Group PM Module CM supports the multicast profile Yes End Find a higher profile for the remaining group members can support PM Module Choose a lower common profile, and then test it using the OPT messages All CMs support the new profile Yes End All CMs support the new profile Yes Using the new profile Force to replicate the multicast on multiple profiles Using the current profile

25 External Profile Management PMA CMTS CM 1 CM 2 Multicast Profile Optimization Trigger Message Profile Optimization Testing Completed Multicast Profile Test REQ OFDM DS Profile Test RSP (CM1) OFDM DS Profile Test RSP (CM2) Multicast Profile Switchover Message OPT-REQ OPT-RSP OPT-ACK DBC-REQ DBC-RSP OPT-REQ OPT-RSP OPT-ACK DBC-REQ DBC-RSP DBC-ACK DBC-ACK Interfaces between CMTS and PMA 1. CM Joins/Leaves Descriptor 2. OFDM DS Multicast Profile Test Request Message 3. OFDM DS Multicast Profile Test Response Message 4. Multicast Group Information Request Message 5. Multicast Group Information Descriptor

26 HUAWEI To enrich life through communication

27 The World Is Flat Capacity Optimization in a Coaxial Network, Constrained by Total RF Power Karl Moerder PhD, Futurewei Technologies Inc. Fred Harris PhD, San Diego State University

28 The world is flat Capacity Optimization What do we think? What do we know? What can we prove? What does it mean?

29 What do we think? Modulation Constellation Density 256 QAM 256 QAM 256 QAM 256 QAM 256 QAM Input PSD f Frequenc y 800 MHz Output PSD 6dB 12dB 18dB 24dB 30dB f Frequenc y 800 MHz

30 What do we know? Modulation Constellation Density QAM 4096 QAM 1024 QAM 256 QAM 64 QAM 6dB Input PSD f Frequenc y MHz Output PSD 6dB f Frequenc y 800 MHz

31 What can we prove? 4000 Power vs Frequency Power (Arbitrary Scale) Frequency (MHz) 64-QAM 16-QAM 4-QAM

32 What does it mean? It means the closer we come to a flat power spectral density out of the amplifier and into the coax, the more efficiently we use our limited RF power. For the same total RF power, a nearly flat spectrum at the amplifier output significantly reduces the distortion from the amplifier. The above points become increasingly important as the total bandwidth gets wider. Pre-emphasis can be approximated with smaller constellations at higher frequency and boosting the gain for the smaller constellations.

33 Thank You Karl Moerder, Fred Harris,

34 Hi Ho, Hi Ho to a Gigabit We Go Positioning the HFC Network for the New Gigabit Era Phil Miguelez Comcast

35 What s driving the need for a new network architecture? Competition HSD growth D3.1 / R-Phy Future FDX Source

36 Architecture Migration Goals Continue to extend the life of the HFC network Provide expanded capacity needed to meet subscriber usage demands and fend off competitive challenges with D3.1 Reduce node serving area size to increase data capacity per HHP Improve OpEx and network reliability by eliminating RF actives Enable a passive coax access link to the home Provide a future migration path to an all IP / all fiber network Fiber Deep Distributed Access Architecture FTTH

37 Network Migration Options Description / Benefits Cost Pros Cons Drop-In BW Expansion Fiber Deep FTTH Maintain existing station locations and HHP Upgrade Amps and Node electronics to 85/1GHz or 1.2 GHz Enables 1 Gb DS / Mb US peak rates. Lower avg rates High HP per node limits HSD tier rate penetration Lower, $XX/HHP for avg system Large cost variations due to density and plant condition Rapid scalability Operationally familiar No long term network benefit Requires continued node splits Higher cost solution over time Eliminate all RF Amps and reduce serving area size to 128 HP per node max Upgrade Node to 85/1218 MHz Enables true 1 Gb DS / 200 Mb US delivered data rates Lower HP per node permits increased HSD tier rate penetration Modest, $XXX/HHP based on assumed 60/40 aerial / UG split Modular transition to R-PHY Migration path to FTTH Workforce training and scale Slower to ramp Replace HFC network with RFoG / PON overlay Enables 1 Gb DS and US symmetric data rates High, $XXXX/HHP Incremental $XXX to connect each subscriber Low OpEx cost Allows 2Gb to 10Gb HSD Cost prohibitive Slowest to scale Requires all new CPE

38 Fiber Deep N+0 Architecture Concept

39 Fiber Deep N+0 Design Challenges High output node level and tilt to allow maximum HP reach 64 dbmv analog ref output, Linear tilt extension from 1 GHz to 1.2 GHz N+0 node expansion ratio is typically 12:1 (Average: 70 HP, Max: 128 HP) Express cable used to reach additional taps 85 MHz Mid Split migration Legacy STB OOB agility issues means changing out older STB s Maintain existing plant power design Node power consumption design closely watched PS location and size remain unchanged to avoid permit issues Added coax power lines, Access Cable bridging Network design training, Construction training

40 Conclusions / Lessons Learned Gigabit over builders are an expanding threat to every MSO D3.1 plus Fiber Deep N+0 provides the data capacity to meet competitive challenges and deliver Gb per subscriber rates US BW change creates the largest challenge due to the wide array of deployed legacy STB s and requires the most planning Commercial customers determine the node cut in schedule Continual communication with the municipality and customer is key to a successful, pain free network migration plan

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