network economics of optical transport networks with sd fec technology

1 | Infinera Confidential & Proprietary

Network Economics of Optical Transport Networks with SD-FEC Technology Anuj Malik*, Marco Sosa, Onur Turkcu, Vinayak Dangui, Steve Hand, Matthew Mitchell, Serge Melle

IEEE ANTS 2013


Introduction to Hard and Soft Decision FEC

log (BER) (Lower is better)

Optical Signal to Noise Ratio (OSNR) (Lower OSNR is easier to achieve)

Impact of better FEC is to drive down OSNR for a given BER

No FEC

1

Without FEC, a high OSNR is needed to ensure a low Bit Error Rate (BER) 1

HD-FEC

2

HD-FEC recovers bit errors, and allows lower OSNR for a given BER 2

SD-FEC

3

SD-FEC recovers higher levels of bit errors, allowing even lower OSNR for a given BER

3


Gen 1: G.709, Generic Hard Decision FEC • 6.7% OH for 6dB Net Coding Gain

• Interoperable between vendors

Gen 2: Enhanced Hard Decision FEC • 6-10% overhead, up to 9.5dB NCG

• Non-interoperable between vendors

• Higher OH FEC in submarine

Gen 3: Soft Decision FEC • 15-35% overhead, >11dB NCG

• Non-interoperable between vendors

OTN FEC Evolution

Increasing ASIC

Processing Power


The Impact of Overhead on NCG

Increase FEC OH

Q at FEC limit

Transmission Q Value

Lower OH FEC Higher OH FEC

Transmission Q penalty due to the increase in FEC overhead

Y =

Improvement in Q because of stronger FEC

X =

QdB = OSNR + 10*log10

BO

BC Q is proportional to OSNR, but includes this term describing optical noise level and receiver sensitivity

NCG

NCG NCG = X - Y


Network Components for Case Study

PIC Enabled Line Modules 500G Per Slot ULH Reach

• HD-FEC: 9.2dB Coding Gain, 7% Overhead • SD-FEC: 11dB Coding Gain, 15% Overhead

500G Tx PIC

500G Rx PIC

Integrated OTN + DWDM Transport 5T Integrated OTN Switching EDFA and Hybrid Amplifiers

Less Power Less Space More efficient and Scalable


15596km fiber network

11 total add/drop nodes • 211 OLA Sites

The traffic between data-center sites generated according to market data available [www.datacentermap.com]

Total traffic at Year i (Ti) is only the growth over the initial seed

• 𝑇𝑖 = 3.6 × 1 + 0.50 𝑖 − 3.6

Long Haul Datacenter/Express Network Network Topology Details

Topology Details

# Links 11 Average Node Degree 2 Max Node Degree 2 Average Link Distance 1418 Km

Traffic Volume (Tbit/s)

Year 1 Year 2 Year 3 Year 4 Year 5 1.8 4.5 8.5 14.6 23.7


Results – Number of Line Modules

0

50

100

150

200

250

300

350

400

0

50

100

150

200

250

300

350

400

Y1 Y2 Y3 Y4 Y5

SD-FEC Line Modules

HD-FEC Line Modules

Scenario 1: Only HD-FEC Line Modules Deployed Scenario 2: Mix of HD-FEC and SD-FEC Line Modules Deployed

Up to 14% reduction in Line Modules with SD-FEC Technology


Results – Regeneration Sites and Line system Amplifiers

0

1

2

3

4

HD-FEC HD-FEC and SD-FEC

Number of Regenerator Sites

66% reduction in Regenerator Sites

0

100

200

300

400

HD-FEC HD-FEC and SD-FEC

EDFA Hybrid(RAMAN + EDFA)

Line System Amplifiers Deployed

Raman Sites dropped from 42% to 26%

Simplifies network deployment and minimizes network cost


SD-FEC Benefits

Enables increase in optical performance and extends the optical reach

Terrestrial Subsea

Enhanced Optical Performance

Can Close ULH Links > 10,000 KM

Fewer Regen Sites

Lower Network Costs

Benefits


Conclusion

SD-FEC offers better optical performance and longer reach than HD-FEC Technology

SD-FEC reduces TCO by reducing total number of line modules and regenerator sites

SD-FEC simplifies the line system design by reducing number of RAMAN Amplifiers


Thank You


Technology Comparisons

500G Tx PIC

500G Rx PIC

AOLM-500

HD-FEC based 500G Super-Channel Line Module

9.2dB Coding Gain 7% Overhead

500G Tx PIC

500G Rx PIC

AOLM2-500

SD-FEC based 500G Super-Channel Line Module

11dB Coding Gain 15% Overhead