Methods including a method comprising: transmitting a plurality of optical subcarriers from a first node to a second node in a network; transmitting first control information from the first node to the second node; receiving the plurality of subcarriers and the first control information at the second node; outputting from the second node first data indicative of first information carried by a first group of the plurality of optical subcarriers based on the first control information; transmitting second control information from the first node to the second node; and outputting second data from the second node indicative of second information carried by a second group of the plurality of optical subcarriers based on the second control information.

In order to attain an example object of providing a technique to identify each node while suppressing power consumption even in a case where a plurality of nodes which are free space optical communication partners are located relatively far away, in a case where a pulse width of an optical signal is shorter than a sequence length of a code sequence, in an acquisition process, at least one processor included in a communication control apparatus acquires a first partial sequence which is a part of the code sequence and has been generated while the node is receiving one optical signal, acquires a second partial sequence which is a part of the code sequence and has been generated while the node is receiving another optical signal, and generates the code sequence by joining the second partial sequence to an end of the first partial sequence.