Iterative receiver design with CFO, SFO, channel estimation and equalization for OFDM systems

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is a popular technique in modern wireless communications. There are many systems adopting the OFDM technique, such as IEEE 802.11 a/g/n, IEEE 802.16, Digital Video Broadcasting, etc. Since the subcarriers in an OFDM system are mutually orthogonal in the frequency domain, it is quite sensitive to synchronization errors. In wireless communications, sampling frequency offset (SFO) and carry frequency offset (CFO) will induce inter-carrier interference (ICI) and they are fatal to OFDM system. In this paper, we propose a scheme to deal with ICI. An iterative receiver design which joins SFO, CFO and channel estimation is presented. It can bear normalized CFO about ±0.25 from computer simulations, and the new receiver designs which can effectively combat the synchronizaton problem of OFDM is proved.