Improvement of CCI compensation accuracy using feedback phase tracking in MIMO-OFDM systems

In MIMO-OFDM systems, a phase tracking scheme is affected by intercarrier interference (ICI) and cochannel interference (CCI) caused by residual frequency offset. In this paper, we propose a feedback phase tracking scheme to eliminate the effect of both ICI and CCI for MIMO-OFDM systems. The proposed scheme estimates the amount of residual frequency offset in the frequency domain, and compensates for it in the time domain. Thus, the effect of ICI can be reduced. Furthermore, we consider two ways for multiple channel estimation to eliminate the effect of CCI. First is the method that employs midambles. Second is the one that reuses a preamble. Thus, the channel estimation is carried out several times within the packet, and the effect of CCI can be reduced. Simulation results show the proposed scheme can compensate for residual frequency offset and CCI more accurately, and improve the PER performance.