A radiation source generates extreme ultraviolet radiation for a lithographic apparatus as a chamber that is provided with a low pressure hydrogen environment. In some embodiments, measuring the optical error involves taking one or more wavefront measurements. At least a first portion of the wireless data and a second portion of the wireless backhaul data is communicated via Spatial Division Multiple Access, and the first portion of the wireless data utilizes at least some same time-frequency resources as the second portion of the wireless backhaul data. Various measures are taken to make transmission from the subscriber nodes robust.