Joint Iterative CCI and ICI Cancellation for STBC-OFDM System in Fast Fading Channel

Abstract

The performance analysis of Alamouti space time block code (STBC) based orthogonal frequency division multiplexing (OFDM) is often analyzed on the assumption that the channel is constant over Alamouti code period (two consecutive OFDM symbol block). But when the channel is fast fading, this assumption does not hold good and causes co-channel interference (CCI) and inter-carrier interference (ICI). In this paper, an iterative interference cancellation is proposed for STBC OFDM to suppress both the CCI and ICI effect jointly. The proposed scheme consists of two stage interference cancellation. In the first stage the CCI cancellation is performed based on Diagonalized Zero Forcing Detection (DZFD) method. In the latter stage a simplified parallel interference cancellation (PIC) scheme coupled with decision statistics combining (DSC) method is used to cancel the ICI effect and hence improves the system performance. The simulation results verify that the proposed scheme achieves good performance for STBC OFDM system in high mobility environment.