Patent ID: 8275258

Claim:
An optical communication base station which receives an upstream optical signal having an upstream bit rate specific to each one of a plurality of lower order communication units from a corresponding one of said plurality of lower order communication units, and which transmits a downstream optical signal having a downstream bit rate specific to each one of said plurality of lower order communication units to a designated one of said plurality of lower order communication units, said optical communication base station comprising: a first optical signal conversion unit which changes the bit rate of said upstream optical signal and thereby converts said upstream optical signal into a fixed bit-rate inter-station optical signal to be received by a receiving correspondent station, including: an optical-to-electrical conversion unit which converts said upstream optical signal into an electrical signal; a code decision unit which makes code decisions on said electrical signal at a provisional decision clock frequency corresponding to a bit rate equal to an integral multiple of the highest of said upstream bit rates; a storage unit which temporarily stores a code sequence obtained as a provisional code sequence by said code decisions; and a code correction unit which regenerates an original code sequence by correcting code sequence length of said provisional code sequence temporarily stored in said storage unit; a second optical signal conversion unit which converts said inter-station optical signal received from a transmitting correspondent station into said downstream optical signal by changing the bit rate of said inter-station optical signal according to said designated lower order communication unit; and a bit rate detection unit which detects said upstream bit rate based on a length of a receiving period of the provisional code sequence generated from a fixed bit length preamble of said upstream optical signal, wherein using said upstream bit rate, said code correction unit corrects the code sequence length of said provisional code sequence temporarily stored in said storage unit.