MIT Lincoln LaboratorySlides - 1(HPEC)

11Aug10 NBL

Nancy List, Ryan Shoup, Tommy Royster

HPEC 2010

16 September 2010

Evaluating the Performance of DVB-S2 Over Asymmetric

Heterogeneous Optical to Radio Frequency Satellite Links

Using the LLGrid

MIT Lincoln LaboratorySlides - 2(HPEC)

11Aug10 NBL

InformationBits

Decode

Demodulate

System Model

Optical Telescope Radio Frequency Receiver

Heterogeneous Optical / RF Satellite Communications System

InformationBits

FadingChannel

Encode

Interleave

Frame

Modulate

De-interleave

De-frame

Demodulate

AWGN

Encode

Interleave

Frame

Modulate

AWGN

Decode

De-frame

De-interleave

MIT Lincoln LaboratorySlides - 3(HPEC)

11Aug10 NBL

System Parameter Space

End-to-End Decoding Payload Decoding

QPSK

8PSK

16-APSK QPSK

8PSK

16-APSK RF Modulation

Format

Major SystemArchitectural

Trade

1/2

DVB-S2CodeRates

3/52/3

3/4

9/10 1/2

3/52/3

3/4

9/10

1/2

3/52/3

3/4

9/10

1/2

3/52/3

3/4

9/10 1/2

3/52/3

3/4

9/10

1/2

3/52/3

3/4

9/10

Soft vs Hard Decision DecodingSoft Hard Soft Hard Soft Hard Soft Hard

UL Photons per Bit

6 dB 7 dB 8 dB 9 dB 10 dB 11 dB 12 dB 13 dB DL Es/No

6 dB 7 dB 8 dB 9 dB 10 dB 11 dB 12 dB 13 dB

2x

3x

5X

2x

8x

8x

2 x 3 x 5 x 2 x 8 x 8 = 3840 Simulation Data Points to Run!

MIT Lincoln LaboratorySlides - 4(HPEC)

11Aug10 NBL

Computational Approaches Using LLGrid

2.5 3 43.5

100

10-2

10-4

10-6

Err

or

Rat

e

Photons per Symbol (dB)

Best

Point 1:Node 1, 2,..., 7

Point 2:Node 1, 2,..., 7

Point 3:Node 1, 2,..., 7

Point 5:Node 1, 2,..., 7

Point 4:Node 1, 2,..., 7

Point 6:Node 1, 2,..., 7

Point 7:Node 1, 2,..., 7

Good

2.5 3 4

Photons per Symbol (dB)

Node 2

Node 6

Node 7

Node 5

Node 3

Node 1

Node 4

3.5

100

10-4

10-6

Better

Curve 1, Node 1

Curve 3, Node 3

Curve 2, Node 2

Curve 7,Node 7

Curve 6, Node 6

Curve 5, Node 5

Curve 4, Node 4

2.5 3 43.5

100

10-2

10-4

10-6

Err

or

Rat

e

Photons per Symbol (dB)

• Approach: Pass each data point to a separate node

• Short-coming: Some data points will run faster than others. When node finishes data point, it is idle

• Approach: Have each node compute a fixed fraction of each data point

• Short-coming: Some nodes inevitably run faster than others and will sit idle while slower nodes are finishing

• Approach: Have each node tackle each data point until the data point is complete

• Overcomes shortcomings: Slow nodes do not slow down overall simulation, and nodes do not sit idle

• SmartGrid code manages overall simulation

End2End BER

10-2

Err

or

Rat

e

End2End BER