Using time-divisioning to improve the performance of bit-loading algorithms

We show that significant performance improvements are obtained by introducing time-divisioning in the bit-loading algorithms for discrete multitone (DMT) systems. DMT modulation is used in both wired and wireless multiuser, multicarrier systems. Allocation of power among the different users and subchannels, so as to optimize the user data rates, is an important problem. Existing algorithms allow users to transmit together in a given subchannel even when the users are strongly coupled in that subchannel. We propose to use time-divisioning to separate the transmissions of users in subchannels in which they are heavily coupled, while allowing them to transmit together in subchannels where they are lightly coupled. We show that significant improvements in system performance are possible using the proposed scheme, especially at higher values of coupling coefficients.