In this paper

an efficient table look-up method is proposed by using the relationship among bit-error-rate

bits and signal-to-noise.Considering the aggregate spectral density of all the channel impairments

the channel attenuation and the constraint of power spectral density to the maximum bit rates of subchannels

a bit loading and power allocation algorithm is proposed for DMT-based multicarrier communication system.During initialization

the proposed algorithm enables the system with optimal power allocation and bit loading within all constraints.The proposed algorithm converges faster to the optimal solution than some of the existing techniques because of more efficient computation.The system performance margin is improved by the constraint of power spectral density to the maximum bit rates of subchannels.For tracking scenarios

the proposed algorithm makes the system with ability of fast adaptive bit swap without additional system hardware.