simulink based adsl system
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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.
Alberto Serna MartínAndrea Urbano Cayuela
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Introduction
Alberto Serna MartínAndrea Urbano Cayuela
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xDSL Technologies (I)
• Digital Subscriber Line.
• Voice, uplink and downlink.• Bandwidths and bitrates depends on X Technology.• NQAM channels.
Alberto Serna MartínAndrea Urbano Cayuela
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xDSL Technologies (II)
• Based on existing infrastructure.• Twisted pair.
• From User Access Point to the cabinet.
Alberto Serna MartínAndrea Urbano Cayuela
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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Alberto Serna MartínAndrea Urbano Cayuela
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.
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Initialization function
• Complete model configuration.• Carrier frequencies.• Twister pair parameters.• Etc…
• Let’s get a glimpse of it…
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Block diagram: Transmitter
Alberto Serna MartínAndrea Urbano Cayuela
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.
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Block diagram: Receiver (Cabinet)
• Amplification.• Inverse channel response FIR Filter.• Implementation defects.
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Block diagram: Receiver (Cabinet)
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Demonstration
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Alberto Serna MartínAndrea Urbano Cayuela
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.
Alberto Serna MartínAndrea Urbano Cayuela
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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.
Alberto Serna MartínAndrea Urbano Cayuela
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Alberto Serna MartínAndrea Urbano Cayuela
Future Improvements
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Future improvements
• Increase number of carriers.
• Implementation of ‘Error Detection and Correction’ blocks.
• Computational load reduction.• System optimization.
Alberto Serna MartínAndrea Urbano Cayuela
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Alberto Serna MartínAndrea Urbano Cayuela
Thanks for your attention
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