simulink based adsl system
DESCRIPTION
Slides from the development of an ADSL system based on Simulink Software for the Master's Degree in Telecommunication Engineering subject "Implementation of Wrie-line and Satellite Communication Systems", University of Extremadura. Simulink files will be available soon in www.albertosernait.esTRANSCRIPT
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
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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.
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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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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.
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Alberto Serna MartínAndrea Urbano Cayuela
Thanks for your attention
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