Patent ID: 8705974

Claim:
An optical transmission system including a transmitter which transmits to a transmission line an optical signal of multi-level modulation capable of transmitting a plurality of bits in one symbol time, and a receiver which receives the optical signal through the transmission line, the transmitter comprising: a frame divider to rearrange a data string stored in a specified frame into a plurality of logical lanes, and to assign a lane ID, which specifies in what logical lane out of the plurality of logical lanes a start of the data string of the frame is arranged after the data string is rearranged, to a non-scrambled area in an overhead portion of the frame; and an optical transmitter module to multiplex the data string rearranged into the plurality of logical lanes by the frame divider according to the multi-level modulation, and to generate the optical signal of the multi-level modulation by modulating a light in accordance with the multiplexed data signal to transmit the generated optical signal to the transmission line, wherein the lane ID corresponding to one of the plurality of logical lanes is different from the lane IDs corresponding to the other remaining logical lanes, and the receiver comprising: an optical receiver module to recover data from the optical signal and to rearrange a bit string of the data into a same number of physical lanes as that of the plurality of logical lanes; and a frame recovery to detect each of the lane IDs contained in the data string of the physical lanes according to a majority method, to detect an inversion of bits and a swapping of lanes for each of the physical lanes according to the detection result of the lane ID to compensate for the inversion of bits and the swapping of lanes such that the data string of the physical lanes is in a same state as that of the data string of the logical lanes, to rearrange the compensated data string of the logical lanes so as to regenerate the frame, and to remove the lane ID from the non-scrambled area.