ICI cancellation in OFDM by phase rotated data transmission

Abstract

The Frequency offset is one of the main issue of Orthogonal frequency division multiplexing (OFDM) communication systems, distort the orthogonal property of subcarriers out coming in inter-carrier-interference (ICI) which in turn degrades the system performance. Self-cancellation schemes which have been developed to combat the impact of frequency offset on OFDM systems by data symbol repetition on two adjacent subcarriers is a simple and efficient scheme but does not provide any solution to phase error problem caused by frequency offset. Further, for other adjacent data allocation scheme proposed to overcome the problem of phase error, the CIR performance is not much improved. In order to improve it CIR performance, a phase rotated symmetric data symbol transmission scheme to overcome the ICI effect has been suggested in this paper. The system performance is analyzed in terms of carrier to interference ratio (CIR) and bit error rate (BER). Through a detailed analysis and simulation, it is shown that OFDM systems using the proposed ICI self-cancellation scheme performs much better at both low and high frequencies offset situations.