As a next-generation PON technology, TWDM-PON provides the anchor for a comprehensive GPON technology roadmap. Compared to alternative solutions, TWDM-PON is less risky, less disruptive, and offers the best price-performance. Within a span of few short years, through the collaboration of key industry partners, a number of key technical challenges were solved as illustrated in Figure 15, further demonstrating the value of a mature GPON ecosystem.
OLT module v1 4 XFP+EDFA+Mux/Demux
+ +
4 XFP Modules AmplifierOptical
Mux/Demux Tunable filter Tunable laser ONU Module v2： 10G SFP+ with Tunable Rx/Tx ONU Module v1： TF+TL
World’s first 4- in-1 OLT integrated module
World’s first 10G SFP+ ONU module for
TWDM -PON
Integration into BOSAIntegrated
Technical Challenges:
Small Size tunable BOSA(SFP+)
Low cost tunable transmitter and tunable receiver Wavelength calibration and alignment
OLT Module v2
Technical Challenges:
Limited space to accommodate Tx, Rx, Mux/Demux , optical amplifier Burst mode optical amplification ASE noise impact on ONU registration Crosstalk of four channels
Figure 15 Key Technical Challenges Resolved in TWDM-PON
The mixed residential and business application of PON network as illustrated in Figure 16 is an important part of network planning strategy to maximize ROI. Despite increase in upstream traffic, service evolution driven by consumer behavior continues to demand higher downstream bandwidth. Support for asymmetric bandwidth is a market requirement supported by the entire ecosystem, which translates to higher cost for symmetric PON solutions. Symmetric bandwidth is an important part of business service offering but with typical service tiers ranging from 50Mbps to 200Mbps, a relatively small percentage of business subscribers can easily be covered by multi-gigabit asymmetric PON solutions.
A single TWDM-PON OLT port provides 40Gbps DS and 10Gbps US bandwidth over a single ODN. In a mature FTTx deployment, each ODN is expected to connect directly to both residential and business subscribers, as well as a number of cell backhaul and FTTN locations. For the vast majority of FTTN applications serving less than a couple of hundred subscribers per node, this level of uplink capacity is sufficient to support bandwidth demand growth well into the next decade. With commercial launch anticipated in 2016, TWDM-PON positions GPON network for future growth and solidifies GPON as the technology of choice for many operators.
7 Summary
As demonstrated by the modeling result, HFC bandwidth demand for the next 7 years can be met with a combination of node split, mid-split upgrade and DOCSIS 3.1 upgrade. Most would agree these migration steps can be carried out with either centralized or distributed solutions depending on prevailing conditions. Less obvious is the macro trend of an accelerating transition toward a distributed architecture in the access network.
HFC coaxial plants each consisting of hundreds or more modular node facilities are ready to be optimized. However, industry continues to focus on improving the efficiency of hub facilities to maintain flexibility of a physical layer outside plant. This least disruptive approach appears to be perfectly rational. But a closer examination of the competitive landscape presents a different view.
Within many node facilities, digital fibers are being installed by competing wireline and wireless operators offering services to the same pool of potential subscribers. The exponential growth in bandwidth demand is being addressed with innovations in both DOCSIS and FTTx solutions. Economies of scale continue to drive better performance, reliability, and pricing for the FTTx Ethernet Node solutions, most of which are tailored for service delivery over other access media today.
With the introduction of OFDM, DOCSIS 3.1 represents the first major step toward the convergence of cable access and other telecommunications networks. Adoption of Ethernet Node is another step down this convergence path toward better economies of scale. There is little debate about fiber being the future-proof access medium. Newly validated business cases are accelerating FTTx network build-out and continue to tip the balance in favor of the larger scale. Now is the opportune time for MSOs to plan for the coming convergence of HFC node facility and packet digital optical network. The value of Ethernet Node as one of the emerging HFC migration tools is underscored by the strategic implication it would bring to the HFC network.
8 References
[1] Howald, Dr. Robert L, ARRIS. Breathing New Lifespan into HFC: Tools, Techniques, and Optimizations, Cable Show Spring Technical Forum
[2] http://advanced-television.com/2012/04/19/research-mpeg-4-drives-operator-investment/
[3]http://www.cnet.com/news/broadcom-chip-ushers-in-h-265-and-ultrahd-video/
[4] Virtualizing CCAP: Developing a Distributed Access Architecture, a Light Reading Webinar
[5]http://www.prnewswire.com/news-releases/mobile-experts-latest-small-cell-market-forecast-predicts-carrie
r-grade-small-cells-will-outnumber-consumer-femtocells-in-2016-200211811.html
[6] PON, FTTH, and DSL Aggregation Equipment and Subscribers Market Share, Size, and Forecasts: 4Q13 / CY13 Edition, Infonetics Research
[7] http://www.ieee802.org/3/ad_hoc/ngepon/email/msg00012.html
[8] C. Ranaweera, M.G.C. Resender, K.C. Reichmann, P.P. Iannone, P.S. Henry, B-J. Kim, P.D. Magill, K.N. Oikonomou, R.K. Sinha, and S.L. Woodward. Design and Optimization of Fiber-Optic Small-Cell Backhaul Based on an Existing Fiber-to-the-Node Residential Access Network
9 Abbreviations and Acronyms
ADC Analog-to-Digital Converter AES Advanced Encryption Standard AFE Analog Front-endAM Amplitude Modulated
ASE Amplified Spontaneous Emission ASIC Application-specific Integrated Circuit ATDMA Advanced Time Division Multiple Access AVC Advanced Video Coding
BOSA Bi-directional Optical Sub-assembly CAGR Compounded Annual Growth Rate CBR Constant Bit-rate
CCAP Converged Cable Access Platform C-DOCSIS China DOCSIS
CM Cable Modem
CMC Coax Media Converter CNR Carrier-to-Noise Ratio
CPE Customer Premises Equipment DAC Digital-to-Analog Converter
DOCSIS Data over Cable Service Interface Specifications DSL Digital Subscriber Line
DTA Digital Terminal Adaptor
DVB-C Digital Video Broadcasting - Cable DVR Digital Video Recorder
E/O Electrical-to-Optical EOC Ethernet over Coax
EPON Ethernet Passive Optical Network FEC Forward Error Correction
FPGA Field-programmable Gate Array FTTdp Fiber-to-the-Distribution Point FTTH Fiber-to-the-Home
FTTLA Fiber-to-the-Last-Amplifier FTTN Fiber-to-the-Node
FTTx Fiber-to-Anything
GEM Gigabit-capable Passive Optical Network Encapsulation Method GPON Gigabit-capable Passive Optical Networks
HD High Definition
HDTV High Definition Television HEVC High Efficiency Video Coding HFC Hybrid Fiber Coaxial
HHP Household Passed HSI High-speed Internet I-CCAP Integrated CCAP IP Internet Protocol
IPTV Internet Protocol Television LDPC Low Density Parity Code MAC Media Access Control
M-CMTS Modular Cable Modem Termination System MDU Multiple Dwelling Unit
MxU Multiple-Any-media-Unit MPEG Motion Picture Experts Group MSO Multiple-system Operator NG-EPON Next-generation EPON
NG-PON2 40-Gigabit-capable Passive Optical Network NRZ Non-return-to-zero
NTSC National Television Standards Committee ODN Optical Distribution Network
O/E Optical to Electrical
OMCI Optical network termination Management and Control Interface ONU Optical Network Unit
OOB Out-of-Band OPEX Operating Expenses OSP Outside Plant P2P Point-to-Point PAL Phase Alternate Line PHY Physical Layer
PLOAM Physical Layer Operations, Administration and Maintenance PNM Proactive Network Maintenance
PON Passive Optical Network
QAM Quadrature Amplitude Modulation RF Radio Frequency
ROI Return on Investment RS Reed-Solomon
SARFT State Administration of Radio Film and Television SC-QAM Single Carrier QAM
SDTV Standard Definition Television SDV Switched Digital Video SFP Small Form-factor Pluggable SFU Single Family Unit
SNR Signal-to-Noise Ratio STB Set-top Box
T-CONT Transmission Container TDMA Time Division Multiple Access TF Tunable Filter
TL Tunable Laser
TWDM-PON Time and Wavelength Division Multiplex Passive Optical Networks UEQAM Universal Edge QAM
UHDTV Ultra High Definition Television UPS Uninterruptable Power Supplies VOD Video on Demand
VoIP Voice over Internet Protocol
XFP 10 Gigabit Small Form Factor Pluggable XG-PON1 10-Gigabit-capable Passive Optical Network