Simulink Based ADSL System

Simulink Based ADSL System

Alberto Serna MartínAndrea Urbano Cayuela

Master’s Degree in Telecommunication Engineering

Implementation of Wire-line and Satellite Communication Systems

Index

• Introduction.• xDSL Technologies.• ADSL.

• Designed system.• Simplifications and Initialization function.• Block diagram.

• Demonstration.• Conclusions.• Possible future improvements.


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Introduction


3

xDSL Technologies (I)

• Digital Subscriber Line.

• Voice, uplink and downlink.• Bandwidths and bitrates depends on X Technology.• NQAM channels.


4

xDSL Technologies (II)

• Based on existing infrastructure.• Twisted pair.

• From User Access Point to the cabinet.


Technologies

Asymmetric Symmetric

ADSL SDSL

UDSL HDSL

VDSL SHDSL

RADSL IDSL5

ADSL

• Asymmetric DSL.• Uplink: From 25KHz to 131KHz.• Downlink: From 131KHz to 1,1MHz.

• Basic version bitrate up to 2Mbps.• New ADSL technologies and Extended spectrum.• Up to 1Gbps (In development by Huawei).


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Designed System

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Simplifications

• Causes:• High computational load.• Configuration complexity.• Simulink limitations.

• Applied simplifications:• From 256 carriers to 4 carriers.• Error Detection and correction blocks were omitted.• One-way channel.


8

Initialization function

• Complete model configuration.• Carrier frequencies.• Twister pair parameters.• Etc…

• Let’s get a glimpse of it…


9

Block diagram: Transmitter


Block diagram: NQAM modulator

• NQAM demodulator Inverse process.10

Block diagram: Channel (I)

• Channel response.• From twisted pair equations.

• Modeled by an arbitrary magnitude FIR filter block.


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Block diagram: Channel (II)

• Dead bands (Set in the Initialization function).• Ideal channel response equal to -∞dB.• Random or fixed number and bandwidth.


12

Block diagram: Receiver (Cabinet)

• Amplification.• Inverse channel response FIR Filter.• Implementation defects.


13

Block diagram: Receiver (Cabinet)


14

Demonstration


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Conclusions

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Conclusions

• ADSL still is a highly competitive technology.

• Our system is completely functional.• Even taking into account the applied simplifications.

• Due to the Initialization Function many different scenarios can be simulated.• It can be adapted to other xDSL technologies.


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Conclusions

• Simulink is a great tool for system modeling.• Though, it has important limitations.• High computational requirements for fast simulations.• The configuration of systems is really constrained.

• The methodology in which this homework is based on is useful to develop skills highly valued in a typical engineer profile.


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Future Improvements

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Future improvements

• Increase number of carriers.

• Implementation of ‘Error Detection and Correction’ blocks.

• Computational load reduction.• System optimization.


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Thanks for your attention

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