Joint ITU-T/IEEE Workshop on
Next Generation Optical
Access Systems
Introduction to 10G-EPON PMDs
Marek Hajduczenia
Nokia Siemens Networks
marek.hajduczenia@nsn.com
International
Telecommunication
Union
PMD definitions [1]
Some definitions used in Clause 91 802.3av:
• Channel Insertion Loss (ChIL) – total attenuation introduced by
the optical channel (fibre, splitter/s/, splices etc.), excluding
penalties
• Power budget – total difference between minimum AVP launch
power and Rx sensitivity = ChIL + penalties, including:
• PRX type – asymmetric, backward compatible with EPON
• PRX10 – ChIL ≤ 20 dB, compatible with PX10
• PRX20 – ChIL ≤ 24 dB, compatible with PX20
• PRX30 – ChIL ≤ 29 dB, no EPON PMD for compatibility
• PR type – symmetric
• PR10 – ChIL ≤ 20 dB, compatible with PX10
• PR20 – ChIL ≤ 24 dB, compatible with PX20
• PR30 – ChIL ≤ 29 dB, no EPON PMD for compatibility
• Power budget class – comprises PMDs with the same ChIL,
represented by a symmetric (PR) and asymmetric (PRX) PMD
International
e.g. low power budget with PR10 and PRX10 power budgets
Telecommunication
Geneva, 19-20 June 2008 page 2
Union
PR-type PMD in IEEE stack
OLT
ONU
MACC MACC MACC
OAM
OAM
OAM
MPMC (Clause 93)
MAC
MAC
MAC
MAC
RS (Clause 92)
MACC
OAM
MPMC (Clause 93)
MAC
RS (Clause 92)
MACC
OAM
XGMII
XGMII
PCS (Clause 92)
PMA (Clause 92)
PMD (Clause 91)
Tx: 1590 / 1577 nm
Rx: 1260 – 1280 nm
PCS (Clause 92)
PMA (Clause 92)
PMD (Clause 91)
MDI
MDI
Tx: 1270 nm
Rx: 1574 - 1600 nm
PSC
10.3125 GBd →
Notes:
• OAM is optional
• Green layers in scope of 802.3av
Geneva, 19-20 June 2008 page 3
← 10.3125 GBd
Layers:
MACC – MAC Client
OAM – Operation And Maintenance
MPMC – Multipoint MAC Control
MAC – Media Access Control
Layers:
RS – Reconciliation Sublayer
PCS – Physical Coding Sublayer
PMA – Physical Medium
Attachment
International
PMD – Physical Medium
Dependent
Telecommunication
Union
MDI – Medium Dependent Interface
PRX-type PMD in IEEE stack
OLT
ONU
MACC MACC MACC
OAM
OAM
OAM
MPMC (Clause 93)
MAC
MAC
MAC
MAC
RS (Clause 92)
MACC
OAM
MPMC (Clause 93)
MAC
RS (Clause 92)
MACC
OAM
XGMII (Tx)
GMII (Rx)
PCS (Clause 92)
PMA (Clause 92)
PMD (Clause 91)
Tx: 1590 / 1577 nm
Rx: 1260 – 1360 nm
XGMII (Rx)
GMII (Tx)
PCS (Clause 92)
PMA (Clause 92)
PMD (Clause 91)
MDI
MDI
Tx: 1310 nm
Rx: 1574 - 1600 nm
PSC
10.3125 GBd →
← 1.25 GBd
Notes:
• OAM is optional
Layers:
• Green layers in scope of 802.3av
MACC – MAC Client
• XGMII and GMII interfaces are
OAM – Operation And Maintenance
used in single direction only e.g. Tx
MPMC – Multipoint MAC Control
path in XGMII in OLT
MAC – Media Access Control
Geneva, 19-20 June 2008 page 4
Layers:
RS – Reconciliation Sublayer
PCS – Physical Coding Sublayer
PMA – Physical Medium
Attachment
International
PMD – Physical Medium
Dependent
Telecommunication
Union
MDI – Medium Dependent Interface
Power budgets in Clause 91
Power budgets defined in 802.3av 10G-EPON (symmetric and asymmetric)
Description
Low power budget
PRX10
Medium power budget
PR10
PRX20
Downstream rate
Upstream rate
PR20
High power budget
PRX30
PR30
10.3125
1.25
10.3125
1.25
Unit
GBd
10.3125
1.25
10.3125
GBd
Downstream wavelength
1590
1577
nm
Downstream wavelength band
20
6
nm
Upstream wavelength
1310
1270
1310
1270
1310
1270
nm
Upstream wavelength band
100
20
100
20
100
20
nm
Nominal maximum reach (min)
10
20
20
km
Nominal split
1:16
1:16
1:32
-
Maximum ChIL
20
24
29
dB
Minimum ChIL
5
10
15
dB
Note:
• Nominal maximum reach is informative – PMDs may support longer
reach and remain standard compliant;
• PRX30 uses 1 Gb/s link parameters which were not included in
802.3ah specifications (29 ChIL)
International
Geneva, 19-20 June 2008 page 5
Telecommunication
Union
Mapping of PMDs to Power Budgets
PMD – power budget mapping for asymmetric PRX–type power budgets
OLT PMD
PRX-type power budgets
ONU PMD
10/1GBASE-PRX-D1
10/1GBASE-PRX-D2
10/1GBASE-PRX-D3
10/1GBASE-PRX-U1
PRX10
N/A
N/A
10/1GBASE-PRX-U2
N/A
PRX20
N/A
10/1GBASE-PRX-U3
N/A
N/A
PRX30
PMD – power budget mapping for symmetric PR–type power budgets
OLT PMD
PR-type power budgets
ONU PMD
10GBASE-PR-D1
10GBASE-PR-D2
10GBASE-PR-D3
10GBASE-PR-U1
PR10
PR20
N/A
10GBASE-PR-U3
N/A
N/A
PR30
Note:
• number of PMDs < number of power budgets
• one of ONU PMDs (10GBASE-PR-U1) is used in two power budgets:
• 10GBASE-PR-D1 uses PIN Rx and 10GBASE-PR-D2 usesInternational
APD Rx
Geneva, 19-20 June 2008 page 6
Telecommunication
Union
PR10/PR20/PR30 (10G/10G)
TxAVP: 1 (4) dBm
Rx: -24 dBm
10GBASE-PR-D1
[2] OLT [3]
TxAVP: -1 (4) dBm
Rx: -20.5 dBm
Geneva, 19-20 June 2008 page 7
Rx:
[1] PIN
[2] PIN + FEC
[3] APD
[4] APD + FEC
PSC, 1:32
29dB
drop
10GBASE-PR-U1
[2] ONU [1]
10GBASE-PR-D3
[4] OLT [3]
Trunk, 20 klm
24dB
TxAVP: 2 (5) dBm
Rx: –28 dBm
10G DS, 10G US
TxAVP: -1 (4) dBm
Rx: -20.5 dBm
PSC, 1:16
drop
drop
10GBASE-PR-U1
[2] ONU [1]
Trunk, 20 km
20dB
10GBASE-PR-D2
[4] OLT [4]
10G DS, 10G US
Trunk, 10 km
10G DS, 10G US
PSC, 1:16
TxAVP: 5 (9) dBm
Rx: -28 dBm
10GBASE-PR-U3
[4] ONU [2]
TxAVP: 4 (9) dBm
Rx: -28.5 dBm
Tx:
[1] DML
[2] HP DML
[3] EML
[4] EML + AMP
International
Telecommunication
Union
PRX10/PRX20/PRX30 (10G/1G)
TxAVP: 1 (4) dBm
Rx: -24 dBm
TxAVP: 5 (9) dBm
Rx: -27 dBm
TxAVP: 2 (5) dBm
Rx: -29.78 dBm
10/1GBASE-PRX-D1
[1]
[3]
OLT
10/1GBASE-PRX-D2
[3]
[4]
OLT
10/1GBASE-PRX-D3
[2/4] OLT
[3]
Trunk, 20 klm
PSC, 1:16
10G DS, 1G US
Trunk, 20 km
10G DS, 1G US
Trunk, 10 km
10G DS, 1G US
PSC, 1:16
Rx:
[1] PIN
[2] PIN + FEC
[3] APD
[4] APD + FEC
PSC, 1:32
10/1GBASE-PRX-U1
ONU
[2]
[1]
10/1GBASE-PRX-U2
ONU
[2]
[1]
10/1GBASE-PRX-U3
ONU
[4]
[1]
TxAVP: -1 (4) dBm
Rx: -20.5 dBm
TxAVP: -1 (4) dBm TxAVP: 0.6 (5.6) dBm
Rx: -20.5 dBm
Rx: -28.5 dBm
Geneva, 19-20 June 2008 page 8
drop
29dB
drop
24dB
drop
20dB
Tx:
[1] DML
[2] HP DML
[3] EML
[4] EML + AMP
International
Telecommunication
Union
OMAmin
ER=∞
Motivation for Tx relaxation:
• Tx is simpler to manufacture
• lower ER can be traded-off
with higher AVP
Regular Tx • OLT Tx can use:
ER=9dB
• DML: lower ER, higher
AVP, constant OMAmin
• EML: higher ER, lower
AVP, constant OMAmin
OMA
ER=9dB
ER=6dB
Relaxed Tx
ER=6dB
AVPmin
AVPmax
Transmitter relaxation for 10G OLT
Impact on PMD specs:
• OMAmin calculated for ER=9dB and AVPmin
• OLT Tx is required to meet OMAmin, AVPmin and ER=6dB
Geneva, 19-20 June 2008 page 9
International
Telecommunication
Union
AVPmin
ER=∞
AVPmax
ER=9dB
Regular Tx
ER=6dB
ER=6dB
Transmitter relaxation for 10G ONU
Relaxed Tx
ER=9dB
AVP’min
OMAmin
Geneva, 19-20 June 2008 page 10
OMA
Motivation for Tx relaxation:
• currently High Power DML is
assumed to be used in ONU
• high TDP of 3dB
• TDP can be relaxed if EML is
employed
• smaller TDP means that
AVP can be relaxed
• ONU Tx can use:
• DML: lower ER, higher
AVP, constant OMAmin
• EML: higher ER, lower
AVP, constant OMAmin
International
Telecommunication
Union
Wavelength allocation plan
for 10G-EPON
US for
PX10/20
DS for
PX10/20
Analog
video
1560
1540
1500
1480
1360
1600
1580
1574
1560
1540
1360
1280
1260
US for
PRX10/20/30
DS2 for
PR(X)10/20
VID
US
US
802.3av D1.802
DS1 for
PR(X)30
Analog
video
Geneva, 19-20 June 2008 page 11
VID
DS
US
1260
802.3ah
US for
PR10/20/30
Wavelength
[nm]
Wavelength
[nm]
International
Telecommunication
Union
Dual-rate, burst-mode OLT Rx [1]
MAC 10/1
MAC 1/1
MAC 10/10
XGMII
GMII
Notes:
RxTx
10G TIA&LA
to 10G
PMA
1:2
RS
LLID mapping
RxTx
10G Rx
from PON
1260 – 1360 nm
AMP
(optional)
optical
splitter
1G Rx
1G TIA&LA
to 1G
PMA
• signal split in optical domain, +3dB loss in 1:2 splitter
• acceptable in PR(X)10 and PR(X)20 power budgets
10b/8b decoder
66b/64b decoder
Descrambler
Descrambler
PCS
PCS
FEC decoder
FEC decoder
1.25 GHz sync
10.3125 GHz sync
PMA
PMA
PMD
• technically challenging in PR(X)30 power budgets
• two dedicated Rx circuits, optimum sensitivity to 10G / 1G signals
• optional AMP may compensate additional loss of 1:2 splitter
10G LA
from PON
1260 – 1360 nm
to 10G
PMA
10/1G TIA
1:2
10/1G Rx
Notes:
to 1G
PMA
electrical
splitter
1G LA
802.3ah sublayers
• one one PD and TIA is required – need to cope with fast switching
between optimum 10G/1G gain
802.3av sublayers
• with no adjustable gain, sensitivity penalty will be observed
Geneva, 19-20 June 2008 page 12
International
Telecommunication
• several ways to adjust PD and TIA gain exist (see next
slide)
Union
Dual-rate, burst-mode OLT Rx [2]
Notes for (a):
Options for dual-rate OLT Rx
• PD parametric values are fixed;
• Rx sensitivity has 2 dB penalty – can be
divided evenly into 10G and 1G path;
Notes for (b):
• APD bias is fixed, TIA transimpedance is
switched depending on target data rate;
• Rx sensitivity has 1 dB penalty – can be
divided evenly into 10G and 1G path;
Notes for (c):
• APD bias and TIA transimpedance are
switched depending on target data rate;
• Rx sensitivity has no penalty (ideally);
• design is complex and expensive in
terms of control circutry;
International
Geneva, 19-20 June 2008 page 13
Telecommunication
Union
Dual-rate EPON stack
MAC 1/1
MAC 10/1
MAC 10/10
MAC
RS
GMII
10/1G DS 10/1G US OLT
802.3av
XGMII
PCS
PMA
PMD
1270 nm
1577 nm
1590 nm
1310 nm
1490 nm
PMD
PMA
PCS
GMII
GMII
XGMII
XGMII
RS
MAC
1/1G ONU
802.3ah
Geneva, 19-20 June 2008 page 14
10/1G ONU
802.3av
10/10G ONU
802.3av
International
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Coexistence of EPON and 10G-EPON
• 1/10G downstream using WDM (coexistence with 802.3ah)
• 1/10G upstream using TDMA (dual rate, burst mode
transmission, with coexistence with 802.3ah)
• supported configurations:
• [1/10G DS, 1G US]; [1/10G DS, 1/10G US];
• [10G DS, 1G US]; [10G DS, 1/10G US]; [10G DS, 10G US];
Geneva, 19-20 June 2008 page 15
International
Telecommunication
Union
Conclusions
•
Clause 91 PMDs support symmetric and asymmetric operation:
• WDM separation for downstream
• dual-rate, burst-mode transmission for upstream
•
Three power budget classes defined: 20, 24 and 29 dB ChIL
• RS (255,223) FEC is always enabled
• some PMDs may have to use optical post/preamplifier
•
Backward compatible with existing 802.3ah equipment
• evolutionary system upgrade supported
• 802.3ah ONUs do not need to be replaced
Geneva, 19-20 June 2008 page 16
International
Telecommunication
Union