Mixed-tone normalised orthogonal gradient adaptive per-tone DMT equalisation

A mixed-tone normalised orthogonal gradient adaptive algorithm is introduced for per-tone equalisation in discrete multitone systems. We describe briefly about the normalised orthogonal gradient adaptive algorithm that is formulated from the filtered gradient adaptive algorithm by introducing an orthogonal constraint between the direction vectors. By means of the mixed-tone cost function, the sum of weight-estimated errors is minimised in order to achieve the solutions for different per-tone equalisers. Simulation results reveal that bit rate performance can be improved in comparison with the existing recursive least squares algorithm.