An arrangement is described for adapting outer loop precoder phase combiner in a radio communication system having coordinated multipoint transmission. In the arrangement ACK/NACK-message received as a response to a transmitted data packet is used for adapting the phase. When a NACK-message is received the phase may be adapted or it may be further determined if the error was due to error in channel code or due to destructive inter-point signal combining. If the error was due to destructive combining the phase is adjusted.