Splitterless multicarrier modem

Abstract

A modem for use in Digital Subscriber Line communications transmits and receives data over the local subscriber loop in common with voice information over the loop, while avoiding the need for voice/data splitters. The modem responds to disruptions associated with “disturbance events” such as on-hook to off-hook transitions and the like by rapidly switching between pre-stored channel parameter control sets defining communications over the loop under varying conditions. In addition to changing parameter control sets responsive to a disturbance event, the modem may also change transmission power levels and other system parameters such as frequency domain equalizer characteristics. Further, provisions are made for reduced bandwidth communications under selected conditions.

1 . (canceled)  
     
     
         2 . A method that switches between different communication 
 parameters that are stored on a modem upon the detection of an event, the different communication parameters comprising:    a first bit allocation table including a transmitter section and a receiver section, each section including a subchannel indicator including a corresponding bit allocation section and a gains section, the receiver section further including a frequency domain equalizer coefficient section, a time domain equalizer coefficient section and an echo canceller coefficient section;    a second bit allocation table including at least one second transmitter section and at least one second receiver section, each second section including a second subchannel indicator including a corresponding second bit allocation section and a second gains section, the second receiver section further including a second frequency domain equalizer coefficient section, a second time domain equalizer coefficient section and a second echo canceller coefficient section;    wherein the second sections are collectively a parameter set, and wherein there are a plurality of parameter sets associated with the second bit allocation table.    
     
     
         3 . The method of  claim 2 , wherein the modem is an xDSL modem.  
     
     
         4 . The method of  claim 2 , wherein the event is a disturbance event and communication switches from using the first bit allocation table to the second bit allocation table upon detection of the disturbance event.