Optical transport apparatus and optical-wavelength defragmenting method

1. An optical transport apparatus transporting an optical multiplexed signal accommodating a radio signal per optical wavelength, the optical transport apparatus comprising a processor configured to:

transport an optical multiplexed signal between the optical transport apparatus and a counterpart apparatus by using a plurality of communication units;

transmit an arbitrary optical wavelength from the optical multiplexed signal passing through ports by using a wavelength selective switch that has the ports respectively connected to the communication units;

control a radio unit in the counterpart apparatus so as to change a frequency of the radio signal in the specified optical wavelength;

change a transmission band of the port through which the optical wavelength passes, according to a change of the frequency of the radio signal; and

control an optical transmission unit of the counterpart apparatus so as to change a center wavelength of an optical wavelength passing through the port to a center wavelength of the changed transmission band of the port.

2. The optical transport apparatus according to claim 1 , wherein the processor is further configured to:

after a transmission band of the port of the specified optical wavelength is changed so as to extend a bandwidth of the optical wavelength by a portion of a free band in a changing direction, change the center wavelength of the optical wavelength passing through the transmission band obtained after an extension change to the center wavelength of the transmission band obtained after the extension change;

after changing the center wavelength of the optical wavelength, change a frequency of the radio signal in the optical wavelength obtained after the center wavelength change; and

after changing a frequency of the radio signal in the optical wavelength obtained after the center wavelength change, change the transmission band of the port through which the optical wavelength passes.

3. The optical transport apparatus according to claim 1 , wherein the processor is further configured to:

after a transmission band of a port of the specified optical wavelength is changed so as to extend a bandwidth of the optical wavelength by a portion of a free band in a changing direction, change a frequency of the radio signal in the optical wavelength passed through the transmission band obtained after the extension change;

after changing a frequency of the radio signal in the optical wavelength passed through the transmission band obtained after the extension change, change a center wavelength of the optical wavelength passing through the transmission band to a center wavelength of the transmission band obtained after the extension change; and

after changing a center wavelength of the optical wavelength, change a transmission band of the port through which the optical wavelength passes.

4. The optical transport apparatus according to claim 1 , wherein the processor is further configured to:

after change of a center wavelength per optical wavelength in the optical multiplexed signal is completed, assign the optical wavelength according to a group of the radio signals;

accommodate the radio signals of the group in the assigned optical wavelength;

change a transmission band of a port passing through the optical wavelength.

5. The optical transport apparatus according to claim 1 , wherein the processor is further configured to:

when a radio signal-free frequency is detected in the optical wavelength in the optical multiplexed signal, determine whether it is possible to change a center wavelength for each of the optical wavelengths, based on a reservation status of the radio signal-free frequency.

6. A defragmenting method of an optical wavelength of an optical transport apparatus including:

ports respectively connected to the communication units transporting an optical multiplexed signal between the optical transport apparatus and a counterpart apparatus, in order to transmit the optical multiplexed signal accommodating radio signals per optical wavelength; and

a wavelength selective switch that transmits an arbitrary optical wavelength from the optical multiplexed signal passing through the ports, the method comprising:

changing, by a processor of the optical transport apparatus, a frequency of the radio signal in the specified optical wavelength;

changing, by the processor, a transmission band of the port through which the optical wavelength passes, according to a change of the frequency of the radio signal; and

changing, by the processor, a center wavelength of an optical wavelength passing through the port to a center wavelength of the changed transmission band of the port.