Bit loading for OFDM with Quasi-constant transmission power

This work addresses the problem of adaptive bit loading typically employed for approaching the capacity of a fading channel. Multi-carrier transmission over frequency-selective fading is employed. In particular, this work is concerned with the question of obtaining an adaptation technique that will keep the transmitted power as constant as possible over all subcarriers, i.e. quasi-constant transmission power, assuming a general, un-constrained set of coded-modulation schemes. A computationally efficient algorithm is described for solving this so-called minimum-deviation problem. The proposed solution is shown to be optimum under a given set of constraints. It is also demonstrated, via simulations, to provide throughput comparable to other known methods whose aim is to optimize system throughput.