A computer algorithm (36) employing decision trees in order to assign wireless communication nodes (12-19,39-43) in a derived spatial arrangement. In a first embodiment, the algorithm (36) assigns nodes to an array of positions corresponding to the positions of luminaires (2-9) in a lighting array (1) to enable the lighting array (1) to be commissioned automatically. In a second embodiment, the algorithm (36) assigns nodes to control groups (49-51) such that the member nodes of a particular control group (49-51) may be controlled by a single switch or sensor (46-48). The use of decision trees allows the final assignment of nodes to be delayed until more information has been taken into account, thus, the algorithm (36) is able to select the best overall configuration.