Digital subscriber line (DSL) technologies can provide a large bandwidth for digital communications over exiting subscriber lines. When transmitting data over subscriber lines, some DSL technologies use a discrete multi-tone (DMT) line code that allocates a plurality of bits for each sub-carrier or tone in each symbol. The DMT may be adjusted to various channel conditions that may occur at each end of a subscriber line. Typically, a plurality of power management (PM) states may be used in DSL technologies. For example, in the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Recommendation G.992.3 entitled “Asymmetric Digital Subscriber Line Transceivers 2 (ADSL2)” and Recommendation G.992.5 entitled “Asymmetric Digital Subscriber Line Transceivers 2—Extended Bandwidth (ADSL2 plus or ADSL2+)”, which are incorporated herein by reference, three PM or link states are defined. The three PM states comprise a link state for full on mode (denoted as L0), a link state for low power mode (denoted as L2), and a link state for idle mode (denoted as L3). The term state and mode may be used interchangeably herein. For example, a low power mode (LPM) may also be referred to as a low power state.
USPTO Backgrounds
USPTO Backgrounds