A system (1) is configured to obtain a target light level, determine a first set of light settings for one or more lights (13,14,24,25) and/or a first set of daylight blocker settings for one or more daylight blockers (21,22) based on the target light level, control these devices based on the first set(s) of settings, and receive from a user device (31) information indicating a quality of a light-modulated data signal received by the user device from the one or more lights, as determined by the user device. The system is further configured to determine a second set of light settings based on the first set of light settings and the determined signal quality and/or a second set of daylight blocker settings based on the first set of daylight blocker settings and the determined signal quality and control these devices based on the second set(s) of settings.