Abstract-In this paper we compare the performance of OFDM with a cyclic prefix (CP) and isotropic orthogonal transform algorithm (IOTA) OFDM without cyclic prefix under typical system imperfections such as channel estimation errors and frequency offset. The IOTA-OFDM system is based on offset quadrature amplitude modulation (OQAM) and promises an increased immunity to both inter-carrier interference (ICI) and inter-symbol interference (lSI). Moreover, IOTA-OFDM does not require a CP which makes it spectrally more efficient. Our simulation results show that compared to CP-OFDM, IOTA-OFDM is spectrally efficient and more tolerant to interference and frequency offset. Imperfect channel estimation may reduce the gains of IOTA-OFDM but considerable throughput advantages are still obtained for a fixed HER.