Spectral Compensation for Multicarrier Communication

Spectral compensation is an information-processing technique applied in the transmitter to improve the spectral efficiency of multicarrier modulation under a given power spectral density constraint. A set of carefully chosen tones, the so-called information tones, carries data. The remaining tones, referred to as compensation tones, are modulated with a linear combination of the data, such that the spectral characteristic of the transmit signal and thus the throughput are improved. This paper investigates strategies to find the set of compensation tones and presents the optimal solution for the linear combination of the data given the tone-set split. The optimality criterion is maximization of throughput for a time-dispersive Gaussian channel known to the transmitter. Furthermore, a suboptimal design is proposed, which has low runtime-complexity and achieves near-optimal performance.