Allocation of different signal-to-noise margins to different carriers in a multi-carrier system is described. A preferred embodiment comprises assigning signal-to-noise ratio (SNR) margins to carriers in a multi-carrier system, comprises assigning a first SNR margin to a first data service based upon a first service characteristic, assigning a second SNR margin to a second data service based upon a second service characteristic, transmitting data associated with the first data service using the first signal-to-noise margin, and transmitting data associated with the second data service using the second signal-to-noise margin.