A method for operating a communication arrangement, said communication arrangement comprising a plurality of PLC modem devices (10, 20, 21, 22), comprising: monitoring for each of said PLC modem devices (10, 20, 21, 22) a presence of interferences caused by at least one of operating other PLC modem devices, a communication line used for own power line communication and operating radio services, wherein the process of monitoring comprises: generating a pre-defined reference signal by at least one PLC modem device (10, PLC) and transmitting it via at least one communication channel (31, 32, CC) available for own power line communication to at least one possible communication partner device (20, CP), wherein the at least one available communication channel (31, 32, CC) is defined by a specific frequency band and/or a specific time slot, measuring said pre-defined reference signal on channels other than said available communication channels and analyzing the respective measurement data by the at least one possible communication partner device (20, CP) of the at least one PLC modem device (10, PLC), and selecting, based on said measurements, a communication spectrum and/or a communication channel (31, 32, CC) for power line communication between the at least one PLC modem device (10, PLC) and its at least one possible communication partner device (20, CP), to avoid and de-allocate at least one of communication spectra and communication channels associated with at least one of said operating radio services or said other PLC modem devices; and wherein a transmission gain and/or transmission power are raised in order to increase a possible quality of service value or QoS value for quality of service data streams or QoS streams; - wherein information and/or signal components which need a higher QoS value are assigned and mapped to certain carriers; and wherein said certain carriers are given an increased amplitude and/or transmission power in the power line communication process. monitoring for each of said PLC modem devices (10, 20, 21, 22) a presence of interferences caused by at least one of operating other PLC modem devices, a communication line used for own power line communication and operating radio services, wherein the process of monitoring comprises: generating a pre-defined reference signal by at least one PLC modem device (10, PLC) and transmitting it via at least one communication channel (31, 32, CC) available for own power line communication to at least one possible communication partner device (20, CP), wherein the at least one available communication channel (31, 32, CC) is defined by a specific frequency band and/or a specific time slot, measuring said pre-defined reference signal on channels other than said available communication channels and analyzing the respective measurement data by the at least one possible communication partner device (20, CP) of the at least one PLC modem device (10, PLC), and selecting, based on said measurements, a communication spectrum and/or a communication channel (31, 32, CC) for power line communication between the at least one PLC modem device (10, PLC) and its at least one possible communication partner device (20, CP), generating a pre-defined reference signal by at least one PLC modem device (10, PLC) and transmitting it via at least one communication channel (31, 32, CC) available for own power line communication to at least one possible communication partner device (20, CP), wherein the at least one available communication channel (31, 32, CC) is defined by a specific frequency band and/or a specific time slot, measuring said pre-defined reference signal on channels other than said available communication channels and analyzing the respective measurement data by the at least one possible communication partner device (20, CP) of the at least one PLC modem device (10, PLC), and selecting, based on said measurements, a communication spectrum and/or a communication channel (31, 32, CC) for power line communication between the at least one PLC modem device (10, PLC) and its at least one possible communication partner device (20, CP), to avoid and de-allocate at least one of communication spectra and communication channels associated with at least one of said operating radio services or said other PLC modem devices; and wherein a transmission gain and/or transmission power are raised in order to increase a possible quality of service value or QoS value for quality of service data streams or QoS streams; - wherein information and/or signal components which need a higher QoS value are assigned and mapped to certain carriers; and wherein said certain carriers are given an increased amplitude and/or transmission power in the power line communication process. - wherein information and/or signal components which need a higher QoS value are assigned and mapped to certain carriers; and wherein said certain carriers are given an increased amplitude and/or transmission power in the power line communication process.