A method for analyzing a wireless link (3) of a wireless node of a customer premises equipment (CPE) device (1) during operation of the CPE device comprises: performing an active test, during which a data transmission is forced through the wireless link, to obtain a first set of parameters, and performing before or after the active test a passive test, which is a monitoring mode during which a data transmission of the CPE device is monitored, to obtain a second set of parameters. In particular, based on the first set of parameters, it is determined whether and to which extent the wireless link is in an uncertainty zone, and based on the second set of parameters, the decision is made to assign an observed decrease in a measured data rate to physics effects or to interference effects.