Comparison of error probability for OFDM and SC-FDE

The purpose of this paper is to quantify the effects of frequency and timing offsets in orthogonal frequency division multiplexing (OFDM) and single carrier systems and to compare their relative sensitivities. This is done in two ways. First, by simulation and second, by a numerical computation using a method first introduced by Beaulieu. We show that the standard approach, which is based on approximating the ICI (or ISI) term as a Gaussian random variable, is inadequate to characterize performance degradation. Our results show that the Gaussian approximation can be overly optimistic or overly pessimistic, depending upon the case. In contrast the numerical method is shown to agree closely with simulation in all cases. While the numerical method used here has been previously employed for calculation with OFDM, it has not been used in the comparison of single carrier and OFDM.