Linear OFDM precoder design for multiuser wireless communications using cutoff rate optimization

Multiuser wireless communications based on orthogonal frequency division multiplexing (OFDM) technique have two pronouncing advantages. First of all, the equalizer design at the receiver is facilitated by converting the frequency selective fading channel into parallel flat fading channels. Moreover, by providing each user with a non-intersecting fraction of the available number of subcarriers, multiple-access interference (MAI) can be mitigated. However, a serious drawback in this communication scheme is that some subcarriers may be subject to deep fading in the frequency domain. In this paper, a linear precoding technique is proposed in order to solve this problem. The design of our linear precoder is based on the cutoff rate criterion and, in contrast to other existing precoding techniques, only the knowledge of the average relative power and the multipath delays is required at the transmitter.