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Distributed Simulation of Modern Communication Systems Using the Global Grid Exchange. Wireless is Big Business…. Over 1 Billion wireless phone subscribers worldwide. 205,829,280 in the US. About 200,000 cellular base stations (towers) in US. US Revenues of over $100 Billion per year.

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Distributed Simulation of Modern Communication Systems Using the Global Grid Exchange

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Distributed Simulation of Modern Communication Systems Using the Global Grid Exchange


Wireless is Big Business…

  • Over 1 Billion wireless phone subscribers worldwide.

  • 205,829,280 in the US.

  • About 200,000 cellular base stations (towers) in US.

  • US Revenues of over $100 Billion per year.

Grid Simulation of Communication Systems


Simulation of Communication Systems

  • Before any new system is fielded, it must be extensively tested.

  • Testing of proof-of-concept systems starts with computer simulation.

  • Example: Bit-level simulation of the 3-G wireless system UMTS/WCDMA.

Grid Simulation of Communication Systems


A Simple Simulation

  • Channel includes random effects of:

    • Noise (primarily).

    • Fading.

    • Interference.

  • During each trial:

    • A packet or random data is generated and passed through system.

    • Random noise is generated, usually according to Gaussian distribution

Error

Counter

Random

Data

Input

Estimated

Data

Modulator

Demodulator

Communication

Channel

Grid Simulation of Communication Systems


Raw Bit Error Rate of Several Modulations


A More Sophisticated Simulation

  • Channel code adds redundancy in the form of parity bits.

  • Redundancy is used to correct errors.

  • Decoder significantly increases computational complexity of the system.

Random

Data

Input

Error

Counter

Estimated

Data

Encoder

Decoder

Modulator

Demodulator

Communication

Channel

Grid Simulation of Communication Systems


Simulation of IEEE 802.11g


Simulation Run Times


Simulation Run Times


Coded Modulation Library

  • Coded Modulation Library (CML)

    • Developed at WVU.

    • Runs in matlab.

    • Free software (licensed under lesser GPL).

  • Features

    • Modulation: PSK, QAM, APSK, FSK.

    • Coding: convolutional, turbo, LDPC.

    • Information theoretic bounds (channel capacity; outage probability)

    • Standards:

      • Cellular: WCDMA, HSDPA, cdma2000

      • Wireless LAN/MAN: 802.11a/g, 802.16 (Wimax)

      • Satellite: DVB-RCS, DVB-S2

  • Download

    • Google keyword: “turbo codes”, 2nd hit.

    • http://www.csee.wvu.edu/~mvalenti/turbo

Grid Simulation of Communication Systems


  • Initiative of WVHTC Foundation

  • Only statewide public computing grid

  • Desktop access to 1000s of computers

  • WVU is one of the largest providers

Grid Simulation of Communication Systems


Frontier ServerFrontier Control Ctr

Frontier Compute Engine

Frontier SDKFrontier API

Operation

Launch and Listen

Local vs. Remote

Exception handling

Grid Simulation of Communication Systems


Frontier ServerFrontier Control Ctr

Frontier Compute Engine

Frontier SDKFrontier API

Operation

Java & native code

Checkpoint/restart

Prioritization

Grid Simulation of Communication Systems


Frontier ServerFrontier Control Ctr

Frontier Compute Engine

Frontier SDKFrontier API

Operation

Multi-platform

MatLab extensible Highly configurable

Grid Simulation of Communication Systems


Frontier Server

Firewall

Firewall

Frontier Compute Engine

Enterprise

Frontier SDKFrontier API

Configurations

Grid Simulation of Communication Systems


Frontier Server

Frontier Compute Engine

Frontier SDKFrontier API

Configurations

Internet

Grid Simulation of Communication Systems


Frontier Server

Frontier Compute Engine

Frontier SDKFrontier API

Configurations

Grid Simulation of Communication Systems


Frontier Server

Firewall

Frontier Compute Engine

Outsourced

Firewall

Frontier SDKFrontier API

Configurations

Grid Simulation of Communication Systems


MATLAB®

Architecture

CML

Grid Simulation of Communication Systems


Developing Grid Jobs in Matlab

  • Goals:

    • Work in matlab environment.

    • Use same calling syntax as stand-alone CML library.

    • Develop code in matlab, rather than java.

    • Don’t want to require a matlab license on each grid node.

  • Implementation:

    • Use matlab compiler to create stand-alone executables.

      • Considered to be “native code”.

    • Enable cluster to run native code.

    • One grid node used per simulation scenario.

    • Send the compiled code plus a data file to the grid node.

Grid Simulation of Communication Systems


System Requirements and Setup

  • End Computer

    • Java RE 5 and SDK

    • Matlab 7

      • Compiler needed if you want to make changes to the code.

    • CML 1.5 or above

      • http://www.iterativesolutions.com

    • Global Grid Exchange software and account:

      • http://www.globalgridexchange.com

  • Grid

    • Windows or linux.

    • Nodes must be on the Global Grid.

    • Must be set to allow native code.

    • Either matlab 7 or matlab runtime environment

Grid Simulation of Communication Systems


Job Controller


4

7 tasks ran in parallel on the grid

2 were slower than the local machine

5 were faster

After 150 minutes, the local computer executed

159,013 trials, while the grid executed 1,408,483,

nearly an order of magnitude improvement.

3.5

3

2.5

Computations relative to 1.2 GHz P3

2

1.5

1

Dotted black line shows performance of local laptop,

a 1.2 GHz PIII w/ 512 Mbytes RAM, which processes

64,140 simulation trials per hour.

0.5

0

0

0.5

1

1.5

2

2.5

Time in hours


14

11 tasks running in parallel

1 was faster than the local machine (gold line)

9 were slightly slower

1 was significantly slower (red line)

After 9.5 hours, the grid executed 6,019,410,

nearly an order of magnitude improvement

over running locally.

12

10

8

Computations relative to 1.2 GHz P3

6

4

Dotted black line shows performance of local laptop,

a 1.2 GHz PIII w/ 512 Mbytes RAM, which processes

64,140 simulation trials per hour.

2

0

0

1

2

3

4

5

6

7

8

9

10

Time in hours


40

11 tasks running in parallel

After 24 hours, the grid executed 16,630,510 trials

an order of magnitude improvement

over running locally.

35

30

25

Computations relative to 1.2 GHz P3

20

15

10

5

0

0

5

10

15

20

25

Time in hours


Monte Carlo Optimization

  • With the ability to run large numbers of simulations in parallel, it is possible to determine optimum system parameters via Monte Carlo simulation.

  • Example: FSK modulation.

    • Used in most military communication systems.

    • Also used in GSM cell phones and Bluetooth devices.

    • Several parameters to optimize:

      • Modulation order (number of frequencies)

        • h=0 to 1 in 0.01 increments

      • Modulation index (frequency spacing)

        • M=2, 4, 8,or 16

      • Code rate (amount of redundancy in error control code).

        • Rate is determined by h, M and amount of available bandwidth

Grid Simulation of Communication Systems


2

1.8

1.6

1.4

1.2

1

Rate

0.8

0.6

CM Capacity of 4-FSK h=0.5 in Fading

0.4

0.2

0

5

10

15

20

25

30

35

40

Eb/No in dB


Credits

  • WVU Graduate Student

    • Raja Katuri

  • Parabon Programmer/Engineer

    • Jim O’Connor

  • Parabon Systems Staff

    • Mario Bulhoes

    • Dabe Murphy

  • WVU/LCSEE Systems Staff

    • David Krovich

    • Marc Seery

  • The WVU portion of this project was accomplished without federal funding.

Grid Simulation of Communication Systems


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