a transmission device that transmits a signal along a link and method therefor that includes a forward error correction encoder unit to insert error correction information into the signal transmitted along a link and output a corresponding encoded signal . a modulation unit variably modulates the encoded signal and outputs a modulated signal , having a corresponding quadrature amplitude modulation index , to the receiving device . a control unit variably controls the inserted forward error correction information and the quadrature amplitude modulation index based on link quality information with respect to substantially the entire link to increase throughput during periods of reduced environmental degradation .