1. DSP2 Project ADSL Equalization Students: Dung Nguyen Quoc- Master Student Tudor Tesu- Erasmus Student Supervisor: Jan Vangorp

2. 4 December 20082 ADSL Equalization- General Topics Asymmetric Digital Subscriber Line (ADSL) is a form of DSL (Digital Subscriber Line), a data communication technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem. Broadband communications over telephone lines is summarized in the next table: A gateway is commonly used to make an ADSL connection; the application of ADSL is on GSTN (General Switched Telephone Network), FDM (Frequency Division Multiplexed) group-band and cellular radio. ADSL has several similarities to ISDN (Integrated Services Digital Network or Isolated Subscriber Digital Network). DSP2 Project

3. 3 ADSL Equalization- General Topics ADSL provides access to digital services at several Mb/s over the ordinary wire-pair connection between customers and the local telephone company central office. Available transmission band is divided in a certain number of subbands (sending data in interleaved bit streams), each one transmitting different substreams over different channels. DMT voiceband modems have been adopted for the Asymmetric Digital Subscriber Line (ADSL), which provides digital communication at several Mb/s from a telephone company central office to a subscriber, and a lower rate in the reverse direction, over a normal twisted pair of wires in the loop plant. DSP2 Project4 December 2008

4. DSP2 Project4 ADSL Equalization- General Topics General Trasmission Channel for ADSL- Block Diagram 4 December 2008

5. DSP2 Project5 ADSL Equalization- General Topics Power Spectrum for ADSL Transmission Channel 4 December 2008 Impulse Response of the Simulated Transmission Channel (Matlab)

6. 12 November 2008DSP2 Project6 ADSL Channel Without TEQ- Simulation Results Matlab Code for ADSL Channel without the TEQ Symbols at the Transmitter and at the Receiver when SNR=60dB and CP=15

7. 12 November 2008DSP2 Project7 ADSL Channel Without TEQ- Simulation Results Matlab Code for ADSL Channel without the TEQ Symbols at the Transmitter and at the Receiver when SNR=60dB and CP=7

8. 12 November 2008DSP2 Project8 ADSL Channel Without TEQ- Simulation Results Matlab Code for ADSL Channel without the TEQ Symbols at the Transmitter and at the Receiver when SNR=60dB and CP=2

9. 12 November 2008DSP2 Project9 ADSL Channel Without TEQ- Simulation Results Matlab Code for ADSL Channel without the TEQ Symbols at the Transmitter and at the Receiver when SNR=20dB and CP=2

10. ADSL Equalization - Why equalizing filters? Compensate for the unequal frequency response of some other signal processing circuit or system (e.g. improve the fidelity of sound, remove undesired noise) When the channel consists of telephone lines, the channel transfer function changes from call to call and the equalizing filter needs to be an adaptive filter Time Domain Equalizer restricts Inter Symbol Interference 8DSP2 Project4 December 2008

11. ADSL Equalization – Proposed TEQ 8DSP2 Project4 December 2008 Block Diagram of the Time Domain Equalizer Both the TIR coefficients b, and the TEQ coefficients w, can be obtained iteratively through steepest gradient methods such as Least Mean Square.

12. 12DSP2 Project4 December 2008 ADSL Equalization – TEQ Simulation Results Matlab Code for ADSL Channel with the TEQ Symbols at the Receiver (without TEQ and with TEQ when SNR=60dB and CP=7)

13. 13DSP2 Project4 December 2008 ADSL Equalization – TEQ Simulation Results Matlab Code for ADSL Channel with the TEQ Symbols at the Receiver (without TEQ and with TEQ when SNR=60dB and CP=2)

14. 14DSP2 Project4 December 2008 ADSL Equalization – TEQ Simulation Results Matlab Code for ADSL Channel with the TEQ Symbols at the Receiver (without TEQ and with TEQ when SNR=20dB and CP=2)

15. 15DSP2 Project4 December 2008 ADSL Equalization – TEQ Disadvantage Matlab Code for ADSL Channel with the TEQ Frequency Response of the Communication Channel

16. 12 November 2008DSP2 Project16 ADSL Channel -Simulink Demo http://www.mathworks.com Symbols without and with the Equalizer Filter at the Receiver SNR=60dB

17. 17 ADSL Equalization- Conclusions Conclusions: General transmission channel for ADSL using Matlab/ Simulink MCM Technique used in ADSL modems Equalization methods in time/ frequency domain Bibiliography John A.C Bingham- “Multicarrier Modulation for Data Transmission: An Idea Whose Time Has Come”, IEEE Communications Magazine, May 1990 Koen Vanbleu, Geert Ysebaert, Gert Cuypers and Marc Moonen- “On the relationship between time domain equalizers and PER Tone Equalizers for DMT Based Systems”, IEEE Benelux Signal Processing Symposium, April 2004 Prabin Pandey, Marc Moonen - ”Resource allocation in ADSL variable length per tone equalizers”, IEEE Transactions on Signal Processing, May 2008 http://www.mathworks.com V.S. AbHayawardhana, I.J. Wassell- ”Frequency Scalled Time Domain Equalization for OFDM in Wireless Communications”. K.S. Yap and J.V.McCanny- “Improved time domain equalizer initialization algorithm for ADSL Modems”. DSP2 Project4 December 2008