1. A method, comprising: receiving symbols of a digitally modulated signal, which carries data that is encoded with an Error Correction Code (ECC); correcting the symbols of the received signal with an adaptive receiver loop; computing soft input metrics for the data of the corrected signal; decoding the ECC using a decoder, which estimates soft output metrics based on the soft input metrics, by operating the decoder in an alternating pattern of external iterations that update one or more of the soft input metrics based on one or more of the soft output metrics, and internal iterations that update the soft output metrics but not the soft input metrics; and adjusting the adaptive receiver loop, which corrects the symbols of the received signal, in a schedule that is defined relative to the pattern of the external and the internal iterations of the decoder.