Methods for bit allocation and power tuning for optimizing a setup time in a multi-channel communication system. In one aspect, a bit allocation method includes measuring a signal-to-noise ratio (SNR) of each subchannel of a channel, determining a greatest allocable bit number of each subchannel using the measured SNR of the subchannels, determining a sum of the greatest allocable bit numbers of the subchannels, and determining a difference between the sum of the greatest allocable bit numbers of the subchannels and a target bit number. The currently allocated bit numbers of one or more subchannels is adjusted until a sum of the currently allocated bit numbers is equal to the target bit number.