Distributed control of power in multipoint-to-point orthogonal frequency division multiplexing communication

Abstract

A method for an orthogonal frequency division multiplexing multipoint-to-point communications system is provided. The method includes establishing communication between a first remote unit of a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point, multiple access configuration, transmitting up to a plurality of tones from the first remote unit, the up to a plurality of tones modulated with upstream information using orthogonal frequency division multiplexing, and receiving information from the host unit to adjust a carrier power for tones transmitted by the first of remote unit so that the tones are substantially orthogonal when received at the host unit.

1 . A method for an orthogonal frequency division multiplexing multipoint-to-point communications system, the method comprising: 
 establishing communication between a first remote unit of a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point, multiple access configuration;    transmitting up to a plurality of tones from the first remote unit, the up to a plurality of tones modulated with upstream information using orthogonal frequency division multiplexing; and    receiving information from the host unit to adjust a carrier power for tones transmitted by the first of remote unit so that the tones are substantially orthogonal when received at the host unit.    
     
     
         2 . The method of  claim 1 , wherein receiving information from the host unit to adjust the carrier frequency of tones transmitted by the first of remote unit further comprises: 
 receiving information from the host unit to adjust the carrier power of tones transmitted by the first remote unit such that when any tones are transmitted from the first remote unit and at least one other remote unit of the plurality of remote units, the tones are substantially orthogonal when received at the host unit.    
     
     
         3 . The method of  claim 1 , further comprising: 
 transmitting a reference signal to the host unit from the first remote unit;    receiving an amplitude adjustment command at the first remote unit, the amplitude adjustment command based on an estimate of a amplitude error in the reference signal.    
     
     
         4 . A method for an orthogonal frequency division multiplexing multipoint-to-point communications system, the method comprising: 
 receiving an orthogonal frequency division multiplexing waveform at a multipoint-to-point host unit, the orthogonal frequency division multiplexing waveform comprising a plurality of tones transmitted by the plurality of remote units;    sending an adjustment command from the multipoint-to-point host unit to a first remote unit of the plurality of remote units, the information directing the first remote units to adjust a carrier amplitude of tones transmitted by the first of remote unit so that the tones from each of the plurality of remote units are substantially orthogonal to each other when received at the multipoint-to-point host unit.    
     
     
         5 . The method of  claim 4 , wherein receiving the orthogonal frequency division multiplexing waveform at the multipoint-to-point host unit further comprises receiving a plurality of tones from more than one of the plurality of remote units.  
     
     
         6 . The method of  claim 4 , wherein receiving the orthogonal frequency division multiplexing waveform at the multipoint-to-point host unit further comprises receiving a plurality of tones from one of the plurality of remote units.  
     
     
         7 . The method of  claim 4 , further comprising adjusting each of the plurality of remote units to achieve carrier amplitude alignment within a predefined margin at the host unit of any upstream transmissions by the plurality of remote units.  
     
     
         8 . A method for an orthogonal frequency division multiplexing multipoint-to-point communications system, the method comprising: 
 receiving an orthogonal frequency division multiplexing waveform at a multipoint-to-point host unit, the orthogonal frequency division multiplexing waveform comprising a plurality of tones transmitted by a plurality of remote units; and    adjusting a carrier amplitude of tones transmitted from at least one of the plurality of remote units based on the orthogonal frequency division multiplexing waveform such that the tones from the at least one of the plurality of remote units are substantially orthogonal to any tones received from other of the plurality of remote units when received at the host unit.    
     
     
         9 . The method of  claim 8 , wherein adjusting the carrier amplitude of tones transmitted from at least one of the plurality of remote units further comprises adjusting the carrier amplitude of tones transmitted from at least one of the plurality of remote units so that the plurality of tones transmitted by the plurality of remote units are substantially orthogonal when received at the multipoint-to-point host unit.  
     
     
         10 . The method of  claim 8 , further comprising: 
 adjusting the carrier amplitude of tones transmitted from the at least one of the plurality of remote units such that when any tones are transmitted from the at least one of the plurality of remote units and at least one other remote unit of the plurality of remote units, the tones are substantially orthogonal when received at the multipoint-to-point host unit.    
     
     
         11 . The method of  claim 8 , wherein receiving the orthogonal frequency division multiplexing waveform at the multipoint-to-point host unit further comprises receiving a plurality of tones from more than one of the plurality of remote units.  
     
     
         12 . The method of  claim 8 , wherein receiving the orthogonal frequency division multiplexing waveform at the multipoint-to-point host unit further comprises receiving a plurality of tones from one of the plurality of remote units.  
     
     
         13 . The method of  claim 8 , further comprising adjusting each of the plurality of remote units to achieve alignment of carrier amplitudes within a predefined margin at the host unit of any upstream transmissions by the plurality of remote units.  
     
     
         14 . The method of  claim 8 , wherein receiving the orthogonal frequency division multiplexing waveform comprises receiving the waveform wirelessly.