Post on 02-Jun-2020
transcript
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NG PON and 5G
Ed Harstead, Bill Powell – NokiaEd Walter – AT&T
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The road to PON success: leveraging technologies matured in other domains
50 Gb/s
B/E/GPON 10G PON
2000s 2010s
622 Mb/s, 2.5 Gb/s 10 Gb/s
2015 2020 2025
25G PON
25 Gb/s
Metro
Long haulData center
The old paradigm The new paradigm
First mass deployments:
40 Gb/s Per channel:
50G PON
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The 25G PON ecosystem: closer look
Q: What do we get from the 25G/100G Ethernet ecosystem?
A:
• 25G O-band DML
• 25G O-band EML
• 25G APD
• 25G TIA
• 25G SERDES
25G ecosystem
Source: LightCounting, “High-speed Ethernet Optics, 9th Edition”, March 2019.
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The PON “lag”: Each time, 3 technical challenges to overcome
TRx TRx
Point-to-point link
PON: point-to-multipoint link
OLT
ONU 1
ONU Npower splitter
Lower cost target
Larger power budget
Burst mode
1:N
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IEEE
• IEEE has standardized 25G EPON in P802.3ca
• Stable draft D3.1
• Standard to be published later this year.
ITU-T
• ITU-T SG15/Q2 started a project for >10G PON: G.hsp.
• G.hsp includes 50G PON, but overlooks 25G PON: a mistake.
• A critical mass of ITU-T operators and vendors are proposing a new project to support 25G PON.
• Like with XGS-PON, it is desirable to have common 25G PON PMD requirements for IEEE and ITU-T PONs
25G PON: standardization status
Operators1. AT&T
2. KT
3. SKT
4. TI
5. Telus
6. BT
7. NBN
Government research organizations
1. ETRI
Vendors1. Nokia Corp2. Nokia USA3. Broadcom4. Intel5. Tibit6. Oki7. Corning 8. Sumitomo
9. Mitsubishi10. Ericsson
18 co-signers for 25G PON, ITU-T plenary, 5 February 2020
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25G PON For Business
OR
• IEEE P802.3ca allows for Co-Existence of GPON with 25G PON or XGS with 25G PON. The figure above illustrates the latter.
• Co-Existence is not a prerequisite for 25G PON but would allow for reuse of fiber plant (and splitters).
• The separation of Consumer to XGS and Business to 25G PON allows for a cost-effective, higher end service development for Business without impacting the Consumer customer.
Fiber Cross ConnectFiber Serving Terminal
Distribution
Fiber (F2)
BusinessConsumer
25G PONXGS PONXGS PON XGS PON
Mixed Use
(Business/Consumer)
XGS PON for Consumer
25G PON for Business
OLT
OLT
25G PON
XGS PON
Fiber Frame
Feeder Fiber (F1)
1
n
Split
ter
1
n
Split
ter
Co-Existence
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5G transport over PON: value proposition
Transport
dominates
small cell
capex
• PON transport has been technically feasible for LTE
macrocells. But few PONs were deployed.
• But transport costs need to be solved for the dense 5G business case.
Source: Mobile Experts, “5G Millimeter Wave 2019: Radio Architecture and Outlook”, March 2019.
• PON transport will make sense for 5G when operators evolve to 5G densification.
• In particular, when leveraging an FTTH network for 5G, PON can
- speed time-to-market,
- save capex and facilitate the dense 5G business case.
WDM,
PTP fiberPON
Low density High density
FTTHLTE macrocells 5G small cells?
Currency units Removed due to IEEE rules
RelatitiveCost1.4
1.2
1.0
0.80
0.60
0.40
0.20
0.00
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5G transport requirements CU : Central Unit (may be virtualized)DU : Distributed UnitRU : Radio Unit
5G New Core Antenna
Fx/eCPRI
C-RAN
Fronthaul
S1
D-RAN
Backhaul
F1
Cloud-RAN
(vRAN)
“Midhaul”
1x 5x
<0.250ms<8ms>20 ms
Data rate
Latency
Symmetry
1x
CU DU RU
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Outside of China, midhaul is forecasted to be required for >50% of all radio sites.
Midhaul segment of the 5G market
“DU with RU” = midhaul transport
Source: Ovum, “Mobile operators can move beyond dark-fiber 5G transport”, July 2019.
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Cloud-RAN (vRAN) architectures: midhaul F1 transport over 25G PON
vCU servers
ABIL DU
DU+RUs
OLT
ONU
RUsF1 over 25G PON
ONU
#RUs/ONU, small cell examples1: building façade2: lamp post in middle of street3: traditional area coverage (macro)4: at street intersection; rooftop
÷ =25G PON minimum support: 8-44 ONUs
Typ. configurations 25G PON capacity
Sub-6 GHz, 100MHz, 8 layer MIMO
≥33 RUs per PON
mmWave, 400MHz, 2 layer MIMO
≥44 RUs per PON
D071, Q2, Dusseldorf, Oct/19 - Transport dimensioning for the F1 interface (aka midhaul), T. Pheiffer
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Alternative: WDM PON redux
• Low latency
• Optimized for non-stat-muxable traffic
• Requires relatively exotic and expensive optics
Fronthaul transport challenges
TDM PON:
• Stat muxing of eCPRI traffic: doable in principle, not yetquantifiable.
• How to support stat muxing and low latency simultaneously?
Solution: - Cooperative DBA: being standardized in ORAN and ITU-T as “CTI”.- CTI addresses the stat muxing challenge as well as the PON
ranging window
OLTDUCU
RUs
Fx eCPRI over PON
ONU
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TDM and WDM PON architectures primer: WDM PON is strictly a fronthaul play
Attribute TDM PON WDM PON
Architecture
Physical architecture point-to-multipoint point-to-multipoint
Logical architecture point-to-multipoint point-to-point
Branching elements one power splitter two DWDM muxes
OLT ports per ODN one one for each ONU
Transmitter wavelength fixed OLT: fixed, ONU: tunable
Wavelength tolerances relaxed DWDM
ONU
OLT ONU
ONUOLT
OLTONU
ONU
ONUOLT
These will have a significant impact on cost
Can co-exist with legacy PONs over existing ODNs
Will not co-exist with legacy PONs, will require new ODNs
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• 25G PON can leverage the data center ecosystem for mature low-cost optics and electronics.
• 25G PON is an ideal solution for 5G midhaul/backhaul especially in an FTTH footprint
• 5G fronthaul poses a larger challenge for TDM PONs. WDM PON is an interesting alternative but not without its own challenges.
Conclusions
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