(i9) United States
(12) Patent Application Publication oo) Pub. No.: US 2007/0242597 Al
Geile et al. (43) Pub. Date: Oct. 18,2007
Systems and methods for scanning by remotes in multipoint to-point communication using orthogonal frequency division multiplexing are provided. In one embodiment, a system comprises a host unit; and a plurality of remote units using a multiple access scheme to communicate at the same time with the host unit using orthogonal frequency division multiplexing (OFDM); wherein at least one remote unit scans a band of frequencies for a downstream signal from the host unit; wherein the host unit sends an adjustment signal to the at least one remote unit instructing the at least one remote unit to adjust the timing of transmissions from the remote unit to improve orthogonality of an OFDM waveform received at the host unit; and wherein the host unit allocates orthogonal tones within the OFDM waveform to the plurality of remote units.