Methods and systems for selecting modulation in an orthogonal frequency
division multiplexing system are provided. In one embodiment, a method
for a remote unit of an OFDM multipoint-to-point communications system
comprises: establishing communication between a first remote unit and a
host unit, the first remote unit and a plurality of remote units
communicatively coupled to the host unit in a multipoint-to-point
configuration; transmitting a plurality of tones from the first remote
unit such that tones from the first remote unit and at least one other
remote unit are simultaneously received at the host unit, the plurality
of tones modulated with upstream information using OFDM; modulating up to
a plurality of tones using a first modulation scheme when transmitting a
first type of upstream information; and modulating up to a plurality of
tones using a second modulation scheme when transmitting a second type of
upstream information.