Research Of Inter Carrier Interference Cancellation In Wireless OFDM Mobile Communication System

Orthogonal Frequency Division Multiplexing (OFDM) is believed to be an important technique for future wireline and wireless communications. One of the major disadvantages of such a multi-carrier modulation is the sensitivity of the performance to a frequency offset. The frequency offset can result from a Doppler shift due to mobile movement as well as from a carrier frequency synchronization error. Such a frequency offset causes a loss of the carriers'orthogonality, and hence Inter Carrier Interference (ICI). A Self-Cancellation Scheme has been previously proposed as an ICI mitigation technique for OFDM system. This paper first studies the performance of the system when ICI is generated as a result of channel fading or carrier frequency offset (CFO) respectively, and then combines the ICI Self-Cancellation Scheme with a blind estimator, which uses correlation of the samples at the output of the Discrete Fourier Transform (DFT) to estimate the frequency offset. Simulation results demonstrated that the proposed scheme has the advantage of tolerating larger CFO than traditional Self-Cancellation Scheme, and the ICI can thus be significantly diminished.