Conveying device having at least one movable transport device, wherein - the conveying device has an optical free-beam communication system having at least two transmitting and receiving units (101, 102), which each comprise a transmitter, a receiver and a control unit and one of which is fastened to the movable transport device and the other of which is fastened to another section of the conveying device, and - the at least two transmitting and receiving units (101, 102) have an optical free-beam connection and make it possible to transmit payload data packets between one another in a predefined optical transmission channel, wherein - the data transmission capacity of the transmission channel is greater than the minimum data transmission capacity needed to transmit the payload data packets and the transmission channel therefore provides a free channel region, and - the control unit of at least one of the transmitting and receiving units (101, 102), preferably of both transmitting and receiving units, referred to as the first transmitting and receiving unit (101, 102) below, is suitable for determining the spatial distance between the two transmitting and receiving units (101, 102) using an item of information which is received in the free channel region from the respective other transmitting and receiving unit (101, 102), referred to as the second transmitting and receiving unit (101, 102) below, characterized in that - the information is a period of time which has elapsed or will elapse between the reception of a data packet transmitted by the first transmitting and receiving unit (101, 102) and received by the second transmitting and receiving unit (101, 102) and the subsequent transmission of a data packet from the second transmitting and receiving unit (101, 102) to the first transmitting and receiving unit (101, 102). wherein - the conveying device has an optical free-beam communication system having at least two transmitting and receiving units (101, 102), which each comprise a transmitter, a receiver and a control unit and one of which is fastened to the movable transport device and the other of which is fastened to another section of the conveying device, and - the at least two transmitting and receiving units (101, 102) have an optical free-beam connection and make it possible to transmit payload data packets between one another in a predefined optical transmission channel, - the conveying device has an optical free-beam communication system having at least two transmitting and receiving units (101, 102), which each comprise a transmitter, a receiver and a control unit and one of which is fastened to the movable transport device and the other of which is fastened to another section of the conveying device, and - the at least two transmitting and receiving units (101, 102) have an optical free-beam connection and make it possible to transmit payload data packets between one another in a predefined optical transmission channel, wherein - the data transmission capacity of the transmission channel is greater than the minimum data transmission capacity needed to transmit the payload data packets and the transmission channel therefore provides a free channel region, and - the control unit of at least one of the transmitting and receiving units (101, 102), preferably of both transmitting and receiving units, referred to as the first transmitting and receiving unit (101, 102) below, is suitable for determining the spatial distance between the two transmitting and receiving units (101, 102) using an item of information which is received in the free channel region from the respective other transmitting and receiving unit (101, 102), referred to as the second transmitting and receiving unit (101, 102) below, - the data transmission capacity of the transmission channel is greater than the minimum data transmission capacity needed to transmit the payload data packets and the transmission channel therefore provides a free channel region, and - the control unit of at least one of the transmitting and receiving units (101, 102), preferably of both transmitting and receiving units, referred to as the first transmitting and receiving unit (101, 102) below, is suitable for determining the spatial distance between the two transmitting and receiving units (101, 102) using an item of information which is received in the free channel region from the respective other transmitting and receiving unit (101, 102), referred to as the second transmitting and receiving unit (101, 102) below, characterized in that - the information is a period of time which has elapsed or will elapse between the reception of a data packet transmitted by the first transmitting and receiving unit (101, 102) and received by the second transmitting and receiving unit (101, 102) and the subsequent transmission of a data packet from the second transmitting and receiving unit (101, 102) to the first transmitting and receiving unit (101, 102). - the information is a period of time which has elapsed or will elapse between the reception of a data packet transmitted by the first transmitting and receiving unit (101, 102) and received by the second transmitting and receiving unit (101, 102) and the subsequent transmission of a data packet from the second transmitting and receiving unit (101, 102) to the first transmitting and receiving unit (101, 102).