الفهرس 
CHAPTER 2:: Overviiew off Diigiittall Subscriiber LiineOnly 14 pages are availabe for public view
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Abstract
The Discrete Multi-Tone (DMT) modulation/demodulation scheme is the standard physical-layer transmission technology in Asymmetric Digital Subscriber
Line (ADSL) system. At the DMT transceiver, channel equalization is carried out
through a Time-domain Equalizer (TEq) or a Frequency-domain Equalizer (FEq).
The TEq is introduced to shorten the channel response to a pre-defined length. On
contrary, the FEq is used to compensate for the magnitude and phase distortion
caused by channel.
In this thesis, the Discrete Sine Transform (DST), along with its inverse can be
used instead of the Discrete Fourier Transform (DFT) along with its inverse in the
DMT systems. The results indicate that the proposed DST-DMT system achieves an
improvement in Signal to Noise Ratio (SNR) in each sub-channel as compared to the
conventional DFT-DMT system.
With a Minimum Mean-Squared Error time domain equalizer designed using
the Unit-Tap Constraint (MMSE-UTC) over the eight standard Carrier Serving Area
(CSA). The major advantage of the DST-DMT system is the energy compaction
property of the DST. This property leaves most of the samples at the end of each
symbol close to zero, which reduces the Inter Symbol Interference (ISI),
dramatically, leading to a great performance enhancement.
The combined equalization approaches presented in this thesis yield higher
data rates than the decoupled approaches. So, the data rate can be maximized using
the DST with a combined equalization approach. Also using the Discrete Wavelet
DWT with a combined equalization approach. Simulation results have shown that the
proposed DST-DMT-TEq filter bank system provides a better performance than the
conventional DFT-DMT system. Also that the proposed DWT-DMT-TEq filter bank
system provides a better performance than the conventional DFT-DMT system For
low complexity implementation, the Multi-carrier Equalization by Restoration of
RedundancY (MERRY) algorithm performs blind adaptive channel shortening for a
multi-carrier signals with a Cyclic Prefix (CP). The MERRY algorithm with the DST
approach gives better performance than that of the DFT approach.