An indirect optical free-space communications system provides broadband transmission of high-speed data in transportation vehicles such as aircraft. The system includes a transmitter with a light source that can be modulated and a receiver with a photo detector, adapted to receive light that is emitted from the transmitter and to convert it into an electric signal. The transmitter and the receiver are directed onto at least one common surface, which reflects the light emitted from the transmitter before it reaches the receiver. The free space communications system is cellular and includes several cells, each of which has a transmitter and at least one corresponding receiver. The cells are configured in such a way that crosstalk with a respective adjoining cell is prevented. The cells are thus independent of one another.