Modified orthogonal pilot scheme for Carrier Frequency Offset estimation in 2×2 MIMO system

The emerging of OFDM technique applied on MIMO systems to improve signal quality and capacity has recently gained a lot of attention. The Carrier Frequency Offset (CFO) due to time-varying fading channel is the main cause of the loss of orthogonality among OFDM subcarriers which is linked to inter-carrier interference (ICI). Hence, it is necessary to precisely estimate and compensate the CFO. Especially for data-aid transmission, CFO also has to be correctly estimated in order to track the channel and frequency synchronization. In this paper, we present the new pilot scheme which reduces the effect of data-interference to pilot tone by modifying the orthogonal pilot pattern. The results show that our proposed scheme provides better system performance by reducing the variance of CFO error.