Robust power allocation for minimum BER in a SISO-OFDM system

In this paper we address the problem of the design of a power allocation strategy for an orthogonal frequency division multiplexing (OFDM) system. We assume no spatial diversity at the transmitter and receiver, that is, a single-input-single-output (SISO) channel is considered. The goal is to allocate all the available power at the transmitter among the different carriers according to a minimum mean bit error rate (BER) criterion. When designing this strategy, we assume that channel state information (CSI) is available at the transmitter. Two different approaches are taken. The first one considers that the channel estimates are perfect, whereas the second approach assumes that there is some estimation error, and therefore, this approach is robust in nature. Finally, we propose an efficient algorithm for computing the power allocated to the carriers for both approaches, and show some simulation results in order to compare them.