FM system modes for HD radio

A method for transmitting data over a frequency modulation (FM) radio channel, the FM radio channel having a center frequency and a sideband, the FM radio channel including digital data in a plurality of partitions, each partition being broadcast at a specified frequency within the sideband, the method comprising:

• receiving, with processing circuitry, input bits for transmitting;
• encoding, with the processing circuitry, the input bits using forward error correction encoding to form encoded bits;
• distributing, with the processing circuitry, the encoded bits between an in-band encoded component and a cross-band encoded component, the encoded bits in the in-band encoded component being desynchronized by a specified duration with respect to the encoded bits in the cross-band encoded component;
• allocating, with the processing circuitry, the encoded bits of the in-band encoded component into a first group of partitions of the sideband, the first group corresponding to partitions in a sideband of a legacy service mode;
• allocating, with the processing circuitry, the encoded bits of the cross-band encoded component into a second group of partitions of the sideband, the second group corresponding to partitions that are absent from the legacy service mode;
• modulating, with the processing circuitry, the encoded bits for transmitting;
• and
• directing, with the processing circuitry, the modulated encoded bits to transmitting circuitry for broadcasting in the sideband of the FM radio channel.