Conditional progressive encoding and decoding is discussed, in which a receiver receives a plurality of encoded message segments as a sequence of messages, and sequentially decodes each of the message segments in sequence, in which the decoding of the next encoded message segment is triggered only by successfully decoding the current encoded message segment. On the transmitter side, the transmitter breaks a message payload into a sequence of message segments, and then independently processes each message segment for generating error detection coding and encoding into multiple codeword segments. The transmitter multiplexes each codeword segment over the spectral space of subcarriers to transmit the message.