Computational reduction during idle transmission in DSL modems

This document describes two methods for reducing computational requirements during idle transmission in remote access systems incorporating digital subscriber line (DSL) modems, including asymmetrical DSL (ADSL) systems. These methods save processing power during idle transmission by generating an idle signal using low-complexity techniques. The generated idle signal is made spectrally compatible with xDSL systems and a nondisruptive signaling scheme is used to indicate to the far-end receiver the transition between idle to active or active to idle status. A technique is presented that modulates the phase of the pilot tone to signal status transitions to the remote receiver. The computational complexity at the receiver is reduced because full demodulation and decoding is not required to determine that an idle signal is being transmitted.