Methods for multiframe alignment

Abstract

Methods for multiframe alignment are provided. In one embodiment, a method comprises sharing upstream bandwidth capacity among a plurality of remote units in a manner that permits at least two of the remote units to transmit to a host at any one time using the upstream bandwidth capacity, the upstream bandwidth capacity provided by using orthogonal frequency division multiplexing with a plurality of tones; and causing at least one remote unit to adjust the timing of symbols transmitted on at least one of the plurality of tones in order to improve an alignment of multiframes received at the host.

1 . A method comprising:
 sharing upstream bandwidth capacity among a plurality of remote units in a manner that permits at least two of the remote units to transmit to a host at any one time using the upstream bandwidth capacity, the upstream bandwidth capacity provided by using orthogonal frequency division multiplexing with a plurality of tones; and   aligning multiframes received at the host by adjusting the timing of symbols transmitted on at least one of the plurality of tones by at least one remote unit.   
     
     
         2 . The method of  claim 1 , further comprising adjusting the timing of a first symbol of the multiframes. 
     
     
         3 . The method of  claim 1 , further comprising:
 generating information indicative of a transmission adjustment for the at least one remote unit;   communicating the information to the at least one remote unit; and   adjusting symbol transmissions based at least in part on the information in order to improve the alignment of the multiframes when received at the host.   
     
     
         4 . The method of  claim 1 , further comprising:
 generating information indicative of a transmission adjustment for the at least one remote unit;   communicating the information to the at least one remote unit; and   adjusting a phase of a superframe clock signal of the at least one remote unit based on the information.   
     
     
         5 . The method of  claim 1 , further comprising:
 generating information indicative of a transmission adjustment for the at least one remote unit; and   communicating the information to the at least one remote unit; and   adjusting symbol transmissions based at least in part on the information in order to improve the alignment of a predetermined grouping of symbols when received at the host.   
     
     
         6 . The method of  claim 1 , wherein aligning multiframes received at the host by adjusting the timing of symbols transmitted on at least one of the plurality of tones by at least one remote unit comprises:
 determining a phase shift associated with the receipt at the host of a first symbol of the multiframes; and   causing the at least one remote unit to add a delay to transmissions therefrom, wherein the delay is related to the phase shift.   
     
     
         7 . The method of  claim 1 , wherein aligning multiframes received at the host by adjusting the timing of symbols transmitted on at least one of the plurality of tones by at least one remote unit comprises communicating a command to the at least one remote unit, wherein the at least one remote unit adjusts the manner in which symbols are transmitted on the at least one of the plurality of tones in response to the command. 
     
     
         8 . The method of  claim 1 , further comprising adjusting at least one of a carrier amplitude and a carrier frequency. 
     
     
         9 . The method of  claim 1 , wherein sharing upstream bandwidth capacity among a plurality of remote units further comprises communicating via a wireless distribution network. 
     
     
         10 . A method comprising:
 receiving at a host a plurality of upstream symbols transmitted from a plurality of remote units on a plurality of tones using orthogonal frequency division multiplexing;   determining a timing error for at least one remote unit based on an alignment of a multiframe; and   causing the at least one remote unit to adjust the manner in which symbols are transmitted therefrom based on the timing error.   
     
     
         11 . The method of  claim 10 , wherein the multiframe includes the plurality of upstream symbols. 
     
     
         12 . The method of  claim 10 , wherein causing the at least one remote to adjust the manner in which symbols are transmitted therefrom comprises sending a timing adjustment command to the at least one remote unit, wherein the at least one remote adjusts the manner in which symbols are transmitted therefrom based on the command, wherein the timing adjustment command is related to the timing error. 
     
     
         13 . 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;   estimating a timing error for at least one remote unit, the timing error indicative of an alignment of a predetermined grouping of symbols received at the multipoint-to-point host unit; and   aligning the predetermined grouping of symbols as received at the multipoint-to-point host unit by adjusting a manner in which symbols are transmitted by the at least one remote unit based on the timing error.   
     
     
         14 . The method of  claim 13 , 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. 
     
     
         15 . The method of  claim 13 , 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. 
     
     
         16 . The method of  claim 13 , wherein aligning the predetermined grouping of symbols comprises adjusting each of the plurality of remote units to achieve alignment within a predefined margin at the host unit of multiframes received from the plurality of remote units. 
     
     
         17 . The method of  claim 13 , wherein receiving the orthogonal frequency division multiplexing waveform further comprises receiving a wireless orthogonal frequency division multiplexing waveform via a wireless distribution network.