The present invention relates to a communication device and an access node. The communication device comprises: a processor, and directional antennas; wherein the directional antennas are configured to receive a first signal S1 indicating a calibration request (CR) for an access node; wherein the processor is configured to generate directional beacon signals SDB in response to the calibration request (CR); wherein the directional antennas are further configured to transmit the directional beacon signals SDB towards the access node (300). The access node (300) comprises: a processor, and an antenna array; wherein the antenna array is configured to receive directional beacon signals SDB from at least one communication device; wherein the processor is configured to calibrate the antenna array based on the directional beacon signals SDB.