Patent ID: 8054901

Claim:
A method for generating a signal to transmit data, the method comprising: selecting a first set of carrier frequencies that are integral multiples of a first frequency interval, the first set of carrier frequencies associated with a first symbol length that is the inverse of the first frequency interval; selecting a second set of carrier frequencies that are integral multiples of a second frequency interval, where the second frequency interval is an integral multiple of the first frequency interval and the second set is a subset of the first set, the second set of carrier frequencies associated with a second symbol length that is the inverse of the second frequency interval; and determining whether to generate a symbol waveform for transmitting the data based on the first symbol length or the second symbol length, where generating a symbol waveform based on the second symbol length includes, for each of one or more signal carrier frequencies in the second set, selecting a plurality of associated carrier frequencies in the first set including a peak carrier frequency that is substantially the same as the signal carrier frequency; and modulating waveform frequency components at each of the selected plurality of associated carrier frequencies according to a same data value.