Patent ID: 9374170
Filing Date: 2016-06-21
CPC Classification: H04B,H04L

Claim Text:
1. An optical receiving device, comprising: an adaptive equalizer that comprises: a position estimation unit configured to estimate, based on a first signal component and a second signal component of a reception signal generated by reception of a training sequence pattern transmitted from an optical transmitter, a symbol position of the reception signal, and generates an estimated symbol position, a delay unit configured to provide a delay difference between the first signal component and the second signal component, a control unit configured to set a plurality of symbol displacement amount candidates of displacement amounts for the estimated symbol position, causes the delay unit to generate a plurality of delay differences, and generates a channel estimation symbol position used for channel estimation, a channel estimation unit configured to perform, based on the channel estimation symbol position, channel estimation on a transmission path with the optical transmitter, using the first signal component and the second signal component between which the delay difference is provided by the delay unit, and generates parameters for realizing a characteristic opposite to a transmission path characteristic obtained by the channel estimation, an adaptive equalization unit in which the parameters generated by the channel estimation unit are set and that performs adaptive equalization on the first signal component and the second signal component between which the delay difference is provided by the delay unit, and restores a signal, and an error rate calculation unit configured to calculate an error rate of the signal restored by the adaptive equalization unit, wherein the control unit acquires, from the error rate calculation unit, an error rate for each of the plural delay differences with respect to each of the plural symbol displacement amount candidates, and obtains a final channel estimation symbol position so that the acquired error rate is less than or equal to a reference value and the delay difference provided between the first signal component and the second signal component by the delay unit becomes a maximum available value, and the channel estimation unit generates, based on the final channel estimation symbol position, parameters to be set in the adaptive equalization unit in a case where the delay difference provided by the delay unit is zero.