A base station receives (201) OFDMA messages from a plurality of end user platforms that share all used tones within at least one OFDMA symbol. By one approach this base station then uses (202) a fixed starting time to select contiguous samples from received aggregate multi-user signals wherein the fixed starting time is offset from a reference time that comprises a time at which the base station expects to be receiving the signals from all end users. In combination with the time offset approach noted above or in lieu thereof the base station can process (204) selected contiguous samples using fast Fourier transform and then provide (205) phase rotation with respect to those processed samples. When applying phase rotation, by one approach a phase rotation can be applied (401) to the aggregate multi-user signal and, in addition, individual phase rotation can be applied (402) as determined on a user-by-user basis.