Methods and stations for transmission delay measurements are disclosed. The method includes controlling, by a first station, an optical path selector to work in a first state, and selecting, by the first station, a first fiber to send a first OSC signal to a second station, where the first OSC signal includes a first time stamp. The method further includes controlling, by the first station, the optical path selector to work in a second state, and selecting, by the first station, the first fiber to receive a second OSC signal from the second station at a second receiving moment, where the second OSC signal includes a second time stamp. The method further includes calculating, by the first station, a unidirectional transmission delay between the first station and the second station based on a first sending moment, a first receiving moment, a second sending moment, and the second receiving moment.

Commission devices (1) comprise first transmitters (11) for transmitting activation signals to load devices (2-6), and second transmitters (12) for transmitting numbers of challenge signals to activated load devices (2) that respond by sending back a response signal per challenge signal to the commission devices (1). The commission devices (1) further comprise first receivers (13) for receiving the response signals and controllers (14) for determining time-intervals present between transmissions of the challenge signals and receptions of the response signals. The controllers (14) derive absolute or relative positions of the load devices (2-6) from analyzes such as statistical analyzes of the time-intervals. Load devices (2-6) comprise second receivers (21) for receiving the activation signals and third receivers (22) for receiving the number of challenge signals and third transmitters (23) for sending back the response signals to the commission devices (1). The load devices (2-6) may further comprise loads (26).

Commission devices (1) comprise first transmitters (11) for transmitting activation signals to load devices (2-6), and second transmitters (12) for transmitting numbers of challenge signals to activated load devices (2) that respond by sending back a response signal per challenge signal to the commission devices (1). The commission devices (1) further comprise first receivers (13) for receiving the response signals and controllers (14) for determining time-intervals present between transmissions of the challenge signals and receptions of the response signals. The controllers (14) derive absolute or relative positions of the load devices (2-6) from analyses such as statistical analyses of the time-intervals. Load devices (2-6) comprise second receivers (21) for receiving the activation signals and third receivers (22) for receiving the number of challenge signals and third transmitters (23) for sending back the response signals to the commission devices (1). The load devices (2-6) may further comprise loads (26).