Subcarrier adaptation for multiuser OFDM systems

Low complexity is very important for an adaptive loading algorithm used in OFDM systems in order to adapt the transmit power and the number of bits for each subcarrier within the coherence time of a wireless and mobile channel. An adaptive subcarrier allocation algorithm for a multiuser OFDM system is considered. To overcome the weakness of a conventional allocation scheme, a new adaptive allocation algorithm is proposed to reduce the complexity of the allocation algorithm. Consequently, it is shown that the proposed allocation algorithm has a lower computational complexity than the conventional one, while both algorithms have almost the same BER (bit error rate) performances in a Rayleigh fading environment.