Inter Carrier Interference Cancellation in OFDM Systems

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is an emerging multi-carrier modulation scheme, which has been adopted for several wireless standards such as IEEE 802.11a and HiperLAN2. A well-known problem of OFDM is its sensitivity to frequency offset between the transmitted and received carrier frequencies. This frequency offset introduces inter-carrier interference (ICI) in the OFDM symbol. This project investigates two methods for combating the effects of ICI: ICI self-cancellation (SC), and extended Kalman filter (EKF) method. These two methods are compared in terms of bit error rate performance, bandwidth efficiency, and computational complexity. Through simulations, it is shown that the two techniques are effective in mitigating the effects of ICI. For high values of the frequency offset and for higher order modulation schemes, EKF method performs better than the SC method.