BER analysis of OFDM communication systems with intercarrier interference

For the orthogonal frequency division multiplexing communication systems (OFDM), the theoretical bit error rate (BER) is difficult to obtain when intercarrier interference (ICI) is taken into account. The ICI is a random process caused by channel frequency errors, its distribution function is unknown. This paper gives theoretical BER expressions of OFDM systems, by exploring ICI performance in comparison with conventional single carrier communication systems. First, the BER upper bound is obtained by assuming that the received signals suffer maximum ICI. Then, by using the sequence development BER calculation method, an accurate theoretical BER expression for OFDM systems is derived and validated by simulations. In addition, such a BER calculation method is applied to the "ICI self cancellation OFDM system", which is a system proposed for reducing system ICI signal level. It shows that BER of ICI self cancellation OFDM systems is rather robust to channel frequency errors, while the BER of normal OFDM systems increases rapidly with increasing frequency error.