Synchronization of DMT-based xDSL Systems

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The transmission of high-speed data over band-limited channels may be accomplished through the use of discrete multitone (DMT) modulation. Because of its high-speed data transmission, it is applied in xDSL such as ADSL (asymmetric digital subscriber line) systems and VDSL (very high-speed digital subscriber line) systems. The data cannot be recovered correctly if the synchronization of DMT system is not maintained because of the effect of ISI (intersymbol interference) and ICI (intercarrier interference). This thesis study the symbol synchronization and sample synchronization for VDSL systems. In symbol synchronization, we use near ML (maximum likelihood) approach to find correct symbol allocation. In sample synchronization, we use linear interpolator to detect the frequency offset. The simulations are also conducted under the standard channels and simulation results are compared with those obtained in terms of techniques proposed in existing literature. Since DMT system is almost similar to orthogonal frequency division multiplexed (OFDM) system, the technique developed in this thesis can be applied for the synchronization of OFDM system.