When a sequence of data bits is to be transmitted, the sequence is precoded into data symbols and organized as data frames. For each data frame, a number of phase reference points at predetermined intervals within the data frame are required to allow a receiving device to sufficiently estimate channel effects on the transmitted data frame. If a data frame has a field where inclusion of pilot symbols is undesirable, and if a phase reference point is required within that field, a set of pilot symbols associated with that phase reference point is generated and inserted into the data frame prior to the beginning of the field. The values for each of the pilot symbols in the set are chosen so as to force the phase reference point to a desired phase state.