An optical network unit (ONU) includes a transmitter and receiver to optically communicate with an optical line terminal (OLT) of a passive optical network. The ONU is configured to send an acknowledgment message to the OLT in response to a burst-profile message unicast by the OLT. The acknowledgement message indicates unsupported forward error correction (FEC) code in response to the burst-profile message identifying an FEC code for upstream transmission and the ONU not supporting the FEC code for upstream transmission to the OLT.

A framing method and apparatus in a passive optical network (PON) and a system, where the method includes generating a first transmission convergence (TC) frame and a second TC frame separately, wherein a sum of frame lengths of the first and the second TC frame is 125 microseconds (s), performing bit mapping on the second TC frame to generate a third TC frame, where the bit mapping refers to identifying each bit of the second TC frame using N bits, and sending the first and the second TC frame to an optical network unit (ONU). A line rate corresponding to the second TC frame is lower than 2.488 giga bits per second (Gbps) such that a rate of a receiver on a receiving side is decreased and a bandwidth of the receiver is narrowed, thereby decreasing an optical link loss and increasing an optical power budget.

An optical communication system includes a transmission unit that performs error correction encoding on information to be transmitted, and outputs a result of the error correction encoding as an optical signal, an optical coupler that branches the optical signal, and outputs a first and second optical signals, first and second error correction decoding units that each perform error correction decoding on an optical signal, and a communication disconnection detection unit that, upon detection of a disconnection of communication of the first optical signal, notifies, of the disconnection, the second error correction decoding unit. The second error correction decoding unit performs error correction decoding on the second optical signal when a notification of the disconnection has been received. The first error correction decoding unit performs the error correction decoding with a smaller number of iterations than the number of iterations used by the second error correction decoding unit.

Embodiments of the present invention provide a method and an apparatus for transmitting and receiving a client signal, and relate to the field of communications technologies. The method includes mapping the client signal into channels of a parallel transmission frame, where the parallel transmission frame includes at least two channels; adding an overhead for the channels of the parallel transmission frame after the mapping, to form transmission channels of the parallel transmission frame, where bit rates of the transmission channels of the parallel transmission frame are fixed; and modulating the transmission channels of the parallel transmission frame onto one or more optical carriers in a same optical fiber, and transmitting the optical carrier after the modulation.

A framing method and apparatus in a passive optical network (PON) and a system, where the method includes generating a first transmission convergence (TC) frame and a second TC frame separately, wherein a sum of frame lengths of the first and the second TC frame is 125 microseconds (s), performing bit mapping on the second TC frame to generate a third TC frame, where the bit mapping refers to identifying each bit of the second TC frame using N bits, and sending the first and the second TC frame to an optical network unit (ONU). A line rate corresponding to the second TC frame is lower than 2.488 giga bits per second (Gbps) such that a rate of a receiver on a receiving side is decreased and a bandwidth of the receiver is narrowed, thereby decreasing an optical link loss and increasing an optical power budget.

An optical network unit (ONU) includes a transmitter and receiver to optically communicate with an optical line terminal (OLT) of a passive optical network. The ONU is configured to send an acknowledgment message to the OLT in response to a burst-profile message unicast by the OLT. The acknowledgement message indicates unsupported forward error correction (FEC) code in response to the burst-profile message identifying an FEC code for upstream transmission and the ONU not supporting the FEC code for upstream transmission to the OLT.

Systems and techniques for conditional codeword decoding using packet headers are described herein. A data payload is received. Parity data is removed from the data payload to generate a codeword dataset. Frames are identified in the codeword dataset. Headers of the frames are evaluated to identify port identifiers for the frames. A conditional decoding map is generated based on the port identifiers. The decoding map is transmitted to a conditional decoder to decode codewords included in the conditional decoding map.

An optical communication system includes a transmission unit that performs error correction encoding on information to be transmitted, and outputs a result of the error correction encoding as an optical signal, an optical coupler that branches the optical signal, and outputs first and second optical signals, first and second error correction decoding units that each perform error correction decoding on an optical signal, and a communication disconnection detection unit that, upon detection of a disconnection of communication of the first optical signal, notifies, of the disconnection, the second error correction decoding unit. The second error correction decoding unit performs error correction decoding on the second optical signal when a notification of the disconnection has been received. The first error correction decoding unit performs the error correction decoding with a smaller number of iterations than the number of iterations used by the second error correction decoding unit.