FOLLOW-UP SYNCHRONIZATION TO MAINTAIN SYNCHRONIZATION THROUGHOUT TRANSMISSION
Method for an orthogonal frequency division multiplexing multipoint-to-point communications system are provided. In one embodiment, 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 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 adjusting the up to a plurality of tones transmitted from the first remote unit to maintain the up to a plurality of tones substantially orthogonal with respect to any tones transmitted from at least one other remote unit of the plurality of remote units as 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 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
adjusting the up to a plurality of tones transmitted from the first remote unit to maintain the up to a plurality of tones substantially orthogonal with respect to any tones transmitted from at least one other remote unit of the plurality of remote units as received at the host unit.
2 . The method of claim 1 , further comprising:
transmitting a reference signal to the host unit from the first remote unit;
receiving an adjustment command at the first remote unit, the adjustment command based on an estimate of an error in the reference signal.
3 . The method of claim 1 , wherein adjusting the up to a plurality of tones comprises adjusting at least one of a carrier frequency, a carrier amplitude, and a phase.
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 a plurality of remote units;
communicating between a first remote unit of the plurality of remote units and the multipoint-to-point host unit, the plurality of remote units communicatively coupled to the multipoint-to-point host unit in a multipoint-to-point configuration; and
adjusting one or more of the plurality of tones from the first remote unit based on the orthogonal frequency division multiplexing waveform to maintain the plurality of tones transmitted by the plurality of remote units substantially orthogonal as received at the multipoint-to-point host unit.
5 . The method of claim 4 further comprising:
adjusting one or more of the plurality of tones as transmitted from the first remote unit to maintain the one or more of the plurality of tones substantially orthogonal with respect to any tones transmitted from at least one other remote unit of the plurality of remote units as received at the host unit.
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 more than one of the plurality of remote units.
7 . 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.
8 . The method of claim 4 , wherein adjusting the up to a plurality of tones comprises adjusting at least one of a carrier frequency, a carrier amplitude, and a phase.
9 . 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
updating a transmission characteristic of at least one of the plurality of tones based on the received orthogonal frequency division multiplexing waveform to maintain the plurality of tones substantially orthogonal when received at the host unit.
10 . The method of claim 9 , 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.
11 . The method of claim 9 , 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.