Abstract: A method comprising: at an importer of an IBOC digital radio broadcasting system: establishing a data link to an audio client configured to buffer audio from an audio source over a buffering duration, to produce buffered audio; receiving, from the audio client, an indication of the buffering duration; identifying a logical channel of an IBOC waveform assigned to the audio client and configured to transmit PDUs of the audio at a PDU rate; computing a quantized number of PDUs that is greater than one into which the buffered audio is to be divided at the audio client based on the buffering duration and the PDU rate; sending, to the audio client, an indication of the quantized number of the PDUs; and upon sending importer data requests to the audio client over the data link, receiving, from the audio client, client data responses each including the quantized number of the PDUs.

Abstract: A method performed by at an importer-exporter of an in-band on-channel (IBOC) digital radio broadcasting system comprises: receiving, from a first audio client, first protocol data units (PDUs) (first PDUs) of encoded main audio and that include first sequence numbers that progress in a first order; sending the first PDUs for transmission over a logical channel of an IBOC waveform; receiving, from a second audio client, second PDUs of encoded non-main audio and that include second sequence numbers; aligning the second PDUs to the first PDUs by aligning the second sequence numbers to the first sequence numbers, to produce aligned second PDUs; and switching to sending the aligned second PDUs for transmission over the logical channel in place of the first PDUs such that the second sequence numbers of the aligned second PDUs after switching maintain the first order of the first sequence numbers as established prior to switching.