A data receiver (200, 350, 570, 650), comprising a processing module (210, 360, 560, 660) and decoding module (220, 370, 570, 670), wherein: the processing module (210, 360, 560, 660) is configured to receive first receive data, acquire, according to a training sequence that is in the first receive data and for assisting in channel estimation or channel equalization, an indication signal that indicates a boundary position of the training sequence, and output second receive data obtained after the training sequence is removed from the first receive data and the indication signal to the decoding module (220, 370, 570, 670), wherein the first receive data is obtained by a data transmitter (100, 310, 510, 610) by inserting, according to a boundary position of a forward error correction, FEC, code word, the training sequence into FEC coded data; and the decoding module is configured to determine a boundary position of an FEC code word in the second receive data according to the indication signal and perform FEC decoding on the FEC code word according to the boundary position, wherein the decoding module (220, 370, 570, 670) comprises: a buffering unit, configured to buffer N continuous data blocks if training sequences of N cycles are inserted into one FEC code word, wherein data comprised in one data block is a part between positions indicated by adjacent indication signals in the second receive data; a decoding unit, configured to perform FEC decoding on the N continuous data blocks; a checking unit, configured to check whether a result obtained from the FEC decoding is correct; and a determining unit, configured to determine, if a check result obtained by the checking unit is correct, that a position indicated by a first indication signal corresponding to the N continuous data blocks is the boundary position of the FEC code word in the second receive data, wherein the N is an integer greater than 1. the processing module (210, 360, 560, 660) is configured to receive first receive data, acquire, according to a training sequence that is in the first receive data and for assisting in channel estimation or channel equalization, an indication signal that indicates a boundary position of the training sequence, and output second receive data obtained after the training sequence is removed from the first receive data and the indication signal to the decoding module (220, 370, 570, 670), wherein the first receive data is obtained by a data transmitter (100, 310, 510, 610) by inserting, according to a boundary position of a forward error correction, FEC, code word, the training sequence into FEC coded data; and the decoding module is configured to determine a boundary position of an FEC code word in the second receive data according to the indication signal and perform FEC decoding on the FEC code word according to the boundary position, wherein the decoding module (220, 370, 570, 670) comprises: a buffering unit, configured to buffer N continuous data blocks if training sequences of N cycles are inserted into one FEC code word, wherein data comprised in one data block is a part between positions indicated by adjacent indication signals in the second receive data; a decoding unit, configured to perform FEC decoding on the N continuous data blocks; a checking unit, configured to check whether a result obtained from the FEC decoding is correct; and a determining unit, configured to determine, if a check result obtained by the checking unit is correct, that a position indicated by a first indication signal corresponding to the N continuous data blocks is the boundary position of the FEC code word in the second receive data, wherein the N is an integer greater than 1. a buffering unit, configured to buffer N continuous data blocks if training sequences of N cycles are inserted into one FEC code word, wherein data comprised in one data block is a part between positions indicated by adjacent indication signals in the second receive data; a decoding unit, configured to perform FEC decoding on the N continuous data blocks; a checking unit, configured to check whether a result obtained from the FEC decoding is correct; and a determining unit, configured to determine, if a check result obtained by the checking unit is correct, that a position indicated by a first indication signal corresponding to the N continuous data blocks is the boundary position of the FEC code word in the second receive data, wherein the N is an integer greater than 1.