Joint ITU-T/IEEE Workshop on
Next Generation Optical
Access Systems
Physical layer requirements for
smooth migration from the
current FTTH
Hiroaki Mukai,
Mitsubishi Electric
Geneva, 19-20 June 2008
International
Telecommunication
Union
PON provides FTTH economically
PON is a mainstream of FTTH
Saving the fiber cost, space and
power in comparison with P2P.
Subscribers
ONU
PON
20km
Splitter
Optical Subscriber Line
ONU
ONU
32 branches
Central Office
OLT
Saving the
fiber cost
Saving the
space, power
OLT
ONU
MC
P2P
Optical Subscriber Line
MC
MC
MC
MC
MC
Geneva, 19-20 June 2008
OLT: Optical Line Terminal
ONU: Optical International
Network Unit
Telecommunication
MC : Media Converter
Union
Triple play over PON
High speed internet access
Voice over IP
Video overlay
Apartment House
Central Office
Splitter
Optical Subscriber Line
OLT
Splitter
WDM
OLT
Individual House
Network
Ｖｉｄｅｏ
RG
Geneva, 19-20 June 2008
ONU
RG : Residential Gateway
OLT: Optical Line Terminal
International
ONU: Optical Network
Unit
Telecommunication
Union
Evolution of the transmission
rate of access network
Large capacity of PON (e.g. Next Generation
PON) will be in demand around 2010.
Next Generation
Transmission Rate（bps）
B-PON
G-PON
EPON
NG-PON
10G-EPON
（10G)
10G
Optical fiber
transmission
1G
（600M)
（1G)
（150M)
FTTH service
100M
（25M)
Metallic
transmission
10M
1M
1990
Geneva, 19-20 June 2008
（8M)
ADSL service
（1.5M)
ISDN service
（144K)
100K
1985
（50M)
1995
2000
Year
2005
2010International
Telecommunication
Union
Next Generation PON
Currently, Next Generation PON is
under discussion.
IEEE
Current PON
ITU-T
EPON (1.25G/1.25G)
G-PON (2.5G/1.25G)
Next Generation PON (NG-PON)
10G-EPON
Asymmetric 10G/1G
Symmetric 10G/10G
NG-PON1
Overlay G-PON (2.5G/1.25G) x m
XG-PON1 (10G/2.5G x n)
XG-PON2 (10G/10G)
NG-PON2
Higher rate TDM, DWDM, CDM etc.
Geneva, 19-20 June 2008
International
Telecommunication
Union
NG-PON Migration
New service will drive the NG-PON
migration.
There will be both of new
subscribers and service upgrade
subscribers.
ONU
OLT
ONU
ONU
New subscriber
NG-PON
ONU
NG-PON
ONU
Geneva, 19-20 June 2008
Legacy service
Service upgrade
NG-PON
OLT
New service
International
Telecommunication
Union
Requirements for NG-PON
PON is expected as a cost effective
solution.
1. Equipment cost is important.
2. Installation cost is also concerned.
Co-existence with G/E-PON in the same
ODN.
1. In the age of NG-PON, a large number
of G/E-PON system will be already
installed.
2. Number of new service subscribers will
increase gradually.
Geneva, 19-20 June 2008
International
Telecommunication
Union
Co-existence with current PON
OLT ADD scenario
Addition of NG-OLT to the same ODN as legacy PON.
OLT REPLACE scenario
Replace the OLT to backward compatible NG-OLT.
1. OLT ADD scenario
2. OLT REPLACE scenario
G-ONU
G-ONU
G-ONU
G-OLT
G-ONU
G-ONU
G-ONU
New subscriber
NG-ONU
Add
NG-ONU
G-ONU
NG-OLT
G-ONU
G-ONU
G-OLT
G-ONU
G-ONU
G-ONU
NG-ONU
NG-ONU
Service upgrade
Geneva, 19-20 June 2008
G-OLT
Replace
NG-OLT
(+ G-OLT)
Backward
compatible
Service upgrade
International
Telecommunication
Legacy
OLT/ONU
Union
G-OLT/ONU :
NG-OLT/ONU: NG-PON OLT/ONU
OLT ADD scenario
WDM approach
NG-ONU
NG-PON
MAC
Downstream:
WDM G-OLT/NG-OLT
Rx
Tx
WDM
G-ONU
PON
MAC
ADD
WDM
Tx
WDM
Rx
Splitter
Tx
BCDR
Tx
Rx
BCDR
NG-PON
MAC
G-ONU
PON
MAC
ADD
WDM
Rx
Splitter
Rx
Tx
Geneva, 19-20 June 2008
NG-OLT
WDM
Tx
Downstream:
WDM G-OLT/NG-OLT
Tx
WDM
PON
MAC
Synchronization
is required!
TDMA approach
NG-ONU
NG-PON
MAC
G-OLT
WDM
Upstream:
WDM G-ONU/NG-ONU
Rx
NG-OLT
WDM
Rx
BCDR
G-OLT
WDM
Upstream:
TDMA G-ONU/NG-ONU
NG-PON
MAC
Tx
Rx
BCDR
PON
MAC
G-OLT/ONU : Legacy
OLT/ONU
International
Telecommunication
NG-OLT/ONU: NG-PON
OLT/ONU
Union
BCDR
: Burst CDR
OLT REPLACE scenario
WDM approach
Rx
NG-ONU
NG-PON
MAC
WDM
Rx
WDM
PON
MAC
Splitter
Tx
NG-PON
MAC
G-ONU
PON
MAC
Tx
Rx
Tx
WDM
BCDR
Downstream:
WDM G-OLT/NG-OLT
Tx
WDM
BCDR
WDM
Tx
WDM
Rx
Splitter
Rx
Tx
Geneva, 19-20 June 2008
Rx
PON
MAC
Replace
NG-OLT
NG-PON
/PON
MAC
BCDR
G-OLT
WDM
Upstream:
TDMA G-ONU/NG-ONU
BCDR
PON
MAC
G-OLT
WDM
TDMA approach
NG-ONU
Rx
Upstream:
WDM G-ONU/NG-ONU
Rx
BCDR
NG-PON
MAC
Tx
Downstream:
WDM G-OLT/NG-OLT
Tx
G-ONU
NG-OLT
WDM
WDM
Tx
Tx
Rx
BCDR
PON
MAC
Replace
G-OLT/ONU : Legacy
OLT/ONU
International
Telecommunication
NG-OLT/ONU: NG-PON
OLT/ONU
Union
BCDR
: Burst CDR
Migration scenario comparison
Migration
OLT
ADD
Co-existence
Comments
Evaluation
WDM
WDM which combines and splits NGPON and legacy PON needs to be
equipped at day one.
Individual G-OLT and NG-OLT need
to be synchronized each other.
Technically difficult.
NG-OLT requires also Tx and Rx for
legacy PON.
More expensive than “OLT REPLACE
and TDMA approach”.
No technical problem.
OK!
TDMA
OLT
REPLACE
WDM
TDMA
Geneva, 19-20 June 2008
NG!
NG!
OK!
International
Telecommunication
Union
Requirements for physical layer
Wavelength allocation will be different
depending on the NG-PON migration
scenario.
With “OLT ADD & WDM approach”, only
C/L band are available for NG-PON
wavelength allocation.
With “OLT REPLACE & TDMA approach”,
O-band is also available for NG-PON
wavelength allocation. It helps the cost
reduction of optics.
Geneva, 19-20 June 2008
International
Telecommunication
Union
Wavelength allocation
OLT ADD and WDM approach
Enhancement band (option 1)
ITU-T
G.984.5 NGA
Enhancement band (option 2)
OLT REPLACE and TDMA approach
Upstream
Downstream
PR10/PR20
PR30
IEEE
10G-EPON
Downstream
Upstream
Video
Narrow
Reduced
Regular
G-PON
EPON
1260
1280
1300
1320
1340
O-band
Zero dispersion
Geneva, 19-20 June 2008
1360
1480
E-band
1500
1520
S-band
Attenuation band
1540
1560
C-band
1580
1600
L-band
International
Telecommunication
Union
Cost of optics is important
In the age of NG-PON, there still remains
the green field.
For green field, co-existence is not a
matter, reduction of the equipment cost is
important.
Brown field
G-ONU
G-ONU
NG-OLT
G-ONU
Add
Legacy service
NG-ONU
G-ONU
G-ONU
Replace
NG-OLT
G-ONU
NG-ONU
Green field
New service
NG-ONU
NG-ONU
Geneva, 19-20 June 2008
NG-OLT
International
Telecommunication
Union
Conclusion
NG-PON should be a cost efficient solution.
The cost related to physical layer is dominant in
PON system.
For cost reduction, “OLT REPLACE & TDMA”
approach has advantage. It enables the use of
O-band for upstream.
Common specification between ITU-T and
IEEE will encourage the cost reduction of
optics.
Geneva, 19-20 June 2008
International
Telecommunication
Union