Abstract: Techniques for establishing TTR indication in ADSL Annex C based communication systems are disclosed. The techniques enable, for example, hyperframe alignment and synchronized initialization procedures (e.g., G.hs).

Abstract: A systems and a method for a DMT-based DSL modem to detect time-varying noise dynamically during transmission and adapt to its rapid changes promptly by increasing or reducing data rate while maintaining the transmission and utilizing maximum channel capacity. A DMT-based modem reserves a first set of sub-channels to detect and measure the time-varying noise. The modem further provides reliable communications for control messages through a second set of sub-channels. The control messages are used to adjust communication to adapt to the new noise conditions over all sub-channels.

Abstract: A single ended line testing (SELT) method using a Frequency-Domain Reflectometry (FDR) that uses one or more echo signals originated by transmitting a periodic multi-tone sign, e.g., a REVERB signal, reflected from the hybrid and analyzes it in frequency domain. The REVERB signal is part of the ADSL modem training signal. Therefore the invention can be simply implemented as part of the DMT-based DSL modem because transmitting a multi-tone signal and capturing the frequency response of echo are readily available through the inverse fast Fourier transform/fast Fourier transform (IFFT/FFT) blocks that are used for modulation and demodulation.