Iranian Journal of Information Science and Technology

Vol 4, No 2, ISSN 1726-8125, 2006

COMPARISON OF SOME METHODS INCLUDING USE OF CODING FOR REDUCTION OF ICI IN OFDM CHANNELES

A. R. ZOLGHADR ASLI, Ph.D. , E. E. Dept., School of Engineering, Shiraz University, I. R. of Iran

B. AMIN SHAH, M.S. , E. E. Dept., School of Engineering, Shiraz University, I. R. of Iran

M. A. MASNADI SHIRAZI, Ph.D. , E. E. Dept., School of Engineering, Shiraz University, I. R. of Iran

M. H. GHAMAT, M.S. Student , E. E. Dept., School of Engineering, Shiraz University, I. R. of Iran

Abstract

One of the limitations of orthogonal frequency division Multiplexing (OFDM) in many applications is its sensitivity to frequency shifts, errors normally referred to as carrier frequency offset (CFO). Although, this small offset is negligible in conventional single carrier communication systems, it is a severe problem in the OFDM systems. Because, the carriers in OFDM are inherently closely spaced in frequency, the tolerable frequency offset becomes a very small fraction of the channel bandwidth. Besides, for OFDM communication systems, the frequency offset in mobile radio channels distorts the orthogonality between subcarriers, resulting in intercarrier interference (ICI). In this paper, we analyze and compare the performance of some already existing methods for reducing ICI with new ICI cancellation schemes by simulation. Also the advantage of using a coding scheme is shown.

Keywords - Intercarrier Interference, OFDM, BPSK Modulation, Extended Kalman Filter, Bit Error Rate, Self Cancellation, Modify Self Cancellation, Maximum Likelihood, Coding, AWGN, CFO, PICR

email: zolghadr@shirazu.ac.ir